WO2022145067A1 - Steel material - Google Patents
Steel material Download PDFInfo
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- WO2022145067A1 WO2022145067A1 PCT/JP2021/014779 JP2021014779W WO2022145067A1 WO 2022145067 A1 WO2022145067 A1 WO 2022145067A1 JP 2021014779 W JP2021014779 W JP 2021014779W WO 2022145067 A1 WO2022145067 A1 WO 2022145067A1
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- steel material
- steel
- phosphide
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 145
- 239000010959 steel Substances 0.000 title claims abstract description 145
- 239000000463 material Substances 0.000 title claims abstract description 96
- 239000002245 particle Substances 0.000 claims abstract description 45
- 238000000034 method Methods 0.000 claims abstract description 37
- 239000000203 mixture Substances 0.000 claims abstract description 19
- 239000000126 substance Substances 0.000 claims abstract description 19
- 238000000605 extraction Methods 0.000 claims abstract description 13
- 150000001875 compounds Chemical class 0.000 claims abstract description 6
- 229910052684 Cerium Inorganic materials 0.000 claims description 11
- 229910052692 Dysprosium Inorganic materials 0.000 claims description 11
- 229910052693 Europium Inorganic materials 0.000 claims description 11
- 229910052689 Holmium Inorganic materials 0.000 claims description 11
- 229910052765 Lutetium Inorganic materials 0.000 claims description 11
- 229910052779 Neodymium Inorganic materials 0.000 claims description 11
- 229910052772 Samarium Inorganic materials 0.000 claims description 11
- 229910052771 Terbium Inorganic materials 0.000 claims description 11
- 229910052746 lanthanum Inorganic materials 0.000 claims description 11
- 229910052706 scandium Inorganic materials 0.000 claims description 11
- 229910052691 Erbium Inorganic materials 0.000 claims description 10
- 229910052688 Gadolinium Inorganic materials 0.000 claims description 10
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 10
- 229910052775 Thulium Inorganic materials 0.000 claims description 10
- 229910052769 Ytterbium Inorganic materials 0.000 claims description 10
- 229910052698 phosphorus Inorganic materials 0.000 claims description 10
- 239000011574 phosphorus Substances 0.000 claims description 10
- 229910052727 yttrium Inorganic materials 0.000 claims description 10
- 239000012535 impurity Substances 0.000 claims description 6
- 229910052787 antimony Inorganic materials 0.000 claims description 3
- 229910052745 lead Inorganic materials 0.000 claims description 3
- 229910052709 silver Inorganic materials 0.000 claims description 3
- 230000000694 effects Effects 0.000 description 58
- 229910052751 metal Inorganic materials 0.000 description 32
- 239000002184 metal Substances 0.000 description 32
- 238000005096 rolling process Methods 0.000 description 25
- 238000005098 hot rolling Methods 0.000 description 23
- 238000004519 manufacturing process Methods 0.000 description 23
- 230000007423 decrease Effects 0.000 description 21
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 20
- 239000011651 chromium Substances 0.000 description 19
- ABLZXFCXXLZCGV-UHFFFAOYSA-N Phosphorous acid Chemical compound OP(O)=O ABLZXFCXXLZCGV-UHFFFAOYSA-N 0.000 description 18
- 229910001566 austenite Inorganic materials 0.000 description 18
- 239000010936 titanium Substances 0.000 description 17
- 238000001953 recrystallisation Methods 0.000 description 16
- 239000010949 copper Substances 0.000 description 15
- 239000010955 niobium Substances 0.000 description 15
- 239000011777 magnesium Substances 0.000 description 14
- 239000011669 selenium Substances 0.000 description 14
- 150000003568 thioethers Chemical class 0.000 description 14
- 239000011575 calcium Substances 0.000 description 13
- 239000002244 precipitate Substances 0.000 description 13
- 238000001556 precipitation Methods 0.000 description 13
- 229910052717 sulfur Inorganic materials 0.000 description 13
- 229910052757 nitrogen Inorganic materials 0.000 description 12
- 229910052760 oxygen Inorganic materials 0.000 description 12
- 229920006395 saturated elastomer Polymers 0.000 description 12
- 239000011572 manganese Substances 0.000 description 11
- 238000007670 refining Methods 0.000 description 11
- 150000004767 nitrides Chemical class 0.000 description 10
- 230000007797 corrosion Effects 0.000 description 9
- 238000005260 corrosion Methods 0.000 description 9
- 230000006872 improvement Effects 0.000 description 9
- 238000010438 heat treatment Methods 0.000 description 8
- 229910045601 alloy Inorganic materials 0.000 description 7
- 239000000956 alloy Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 238000001816 cooling Methods 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 229910052777 Praseodymium Inorganic materials 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 5
- 229910052799 carbon Inorganic materials 0.000 description 5
- 238000005266 casting Methods 0.000 description 5
- 239000013078 crystal Substances 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 229910000975 Carbon steel Inorganic materials 0.000 description 4
- 229910019142 PO4 Inorganic materials 0.000 description 4
- 239000010962 carbon steel Substances 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 235000021317 phosphate Nutrition 0.000 description 4
- 229910052761 rare earth metal Inorganic materials 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 230000000087 stabilizing effect Effects 0.000 description 4
- 238000005728 strengthening Methods 0.000 description 4
- 229910000859 α-Fe Inorganic materials 0.000 description 4
- VPIDXLJVGVBFOW-UHFFFAOYSA-N C=1C=[C-]PC=1 Chemical class C=1C=[C-]PC=1 VPIDXLJVGVBFOW-UHFFFAOYSA-N 0.000 description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 229910052791 calcium Inorganic materials 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 150000001247 metal acetylides Chemical class 0.000 description 3
- 229910052750 molybdenum Inorganic materials 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- -1 oxides Chemical class 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 3
- 239000010452 phosphate Substances 0.000 description 3
- 229910052711 selenium Inorganic materials 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- 229910001111 Fine metal Inorganic materials 0.000 description 2
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 2
- 229910052785 arsenic Inorganic materials 0.000 description 2
- 229910052790 beryllium Inorganic materials 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 229910052797 bismuth Inorganic materials 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 210000001787 dendrite Anatomy 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000005868 electrolysis reaction Methods 0.000 description 2
- 238000000866 electrolytic etching Methods 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 229910052735 hafnium Inorganic materials 0.000 description 2
- 238000009616 inductively coupled plasma Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- OHSVLFRHMCKCQY-UHFFFAOYSA-N lutetium atom Chemical compound [Lu] OHSVLFRHMCKCQY-UHFFFAOYSA-N 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- YLRAQZINGDSCCK-UHFFFAOYSA-M methanol;tetramethylazanium;chloride Chemical compound [Cl-].OC.C[N+](C)(C)C YLRAQZINGDSCCK-UHFFFAOYSA-M 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000005204 segregation Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 229910052715 tantalum Inorganic materials 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229910052773 Promethium Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 239000006061 abrasive grain Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 description 1
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 description 1
- 229910001651 emery Inorganic materials 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- OGPBJKLSAFTDLK-UHFFFAOYSA-N europium atom Chemical compound [Eu] OGPBJKLSAFTDLK-UHFFFAOYSA-N 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 description 1
- KJZYNXUDTRRSPN-UHFFFAOYSA-N holmium atom Chemical compound [Ho] KJZYNXUDTRRSPN-UHFFFAOYSA-N 0.000 description 1
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- VQMWBBYLQSCNPO-UHFFFAOYSA-N promethium atom Chemical compound [Pm] VQMWBBYLQSCNPO-UHFFFAOYSA-N 0.000 description 1
- 235000019633 pungent taste Nutrition 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 238000003303 reheating Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- KZUNJOHGWZRPMI-UHFFFAOYSA-N samarium atom Chemical compound [Sm] KZUNJOHGWZRPMI-UHFFFAOYSA-N 0.000 description 1
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 description 1
- VSZWPYCFIRKVQL-UHFFFAOYSA-N selanylidenegallium;selenium Chemical compound [Se].[Se]=[Ga].[Se]=[Ga] VSZWPYCFIRKVQL-UHFFFAOYSA-N 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- 229910052714 tellurium Inorganic materials 0.000 description 1
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- GZCRRIHWUXGPOV-UHFFFAOYSA-N terbium atom Chemical compound [Tb] GZCRRIHWUXGPOV-UHFFFAOYSA-N 0.000 description 1
- 239000011573 trace mineral Substances 0.000 description 1
- 235000013619 trace mineral Nutrition 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C19/00—Alloys based on nickel or cobalt
- C22C19/03—Alloys based on nickel or cobalt based on nickel
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C19/00—Alloys based on nickel or cobalt
- C22C19/03—Alloys based on nickel or cobalt based on nickel
- C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/10—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of nickel or cobalt or alloys based thereon
Definitions
- the present invention relates to steel materials.
- phosphorus (P) may be concentrated at specific points in the steel, for example, between dendrite trees and grain boundaries, and may reduce the toughness, ductility, corrosion resistance and weldability of the steel material. ing.
- P phosphorus
- Patent Document 1 describes a carbon steel slab containing REM and capable of improving toughness by refining the produced phosphide. Further, in Patent Document 1, the steel containing Te, which is a surface active element, has a fine solidified structure, a small amount of P supplied between the dendrite resins, a fine phosphide, and carbon steel slabs. It is taught that the deterioration of toughness of steel is suppressed.
- Patent Document 2 high-purity ferritic stainless steel with improved secondary processing brittleness that is manifested by heat treatment after deep drawing without excessive reduction of P and alloying of trace elements, Si, Mo, etc. Steel plates are listed. Further, in Patent Document 2, in order to improve the secondary processing brittleness, it is effective to precipitate P as a compound in advance to reduce the solid melt P in the steel and delay the grain boundary segregation of P. It is taught that even when the fine phospholides are deposited at the grain boundaries, the effect of delaying the segregation of the grain boundaries of P is greater than the action as the starting point of cracking.
- Patent Document 3 describes a stainless steel in which P remains, positively precipitates as a coarse Ti-based precipitate, detoxifies P, and has improved properties such as workability and yield strength. Further, in Patent Document 3, Ti-based carbides and Ti-based phosphates are coarsened to detoxify solid-dissolved C and solid-dissolved P, and the pinning effect of Ti-based precipitates is used to coarsen the crystal grains of the steel plate. It is taught to control and improve ductility, rigging, and anisotropy of mechanical properties.
- the fine particles present in the steel may be used as pinning particles that suppress the grain growth of the metal structure.
- pinning particles for refining the metal structure of the weld heat-affected zone, but a carbon steel slab utilizing REM phosphate as pinning particles is proposed. (See, for example, Patent Document 4,).
- Patent Document 4 describes a carbon steel slab containing REM, which can improve the toughness of the weld heat-affected zone by utilizing inclusions as pinning particles. Further, in order to utilize inclusions as pinning particles, it is necessary to generate a large amount of particles on the order of submicrons, and ZrS is generated in molten steel to generate slabs after solidification. It is taught that REM phosphide is deposited with ZrS as a precipitation nucleus by reducing the pressure using the temperature difference between the surface layer portion and the central portion.
- the present inventors have secured a certain amount or more of a specific element, and the phosphide obtained by reacting the specific element with phosphorus is used as a pinning particle. We have found that it is possible to suppress the grain growth of a metal structure by using it, and completed the present invention.
- the steel materials that have achieved the above objectives are as follows. (1) By mass%, C: 0.001 to 1.000%, Si: 0.01-3.00%, Mn: 0.10 to 4.50%, P: 0.0005 to 0.300%, S: 0.0300% or less, Al: 0.001-5.000%, N: 0.2000% or less, O: 0.0100% or less, Pr: 0 to 0.8000%, Sm: 0 to 0.8000%, Eu: 0 to 0.8000%, Gd: 0 to 0.8000%, Tb: 0 to 0.8000%, Dy: 0 to 0 .8000%, Ho: 0 to 0.8000%, Er: 0 to 0.8000%, Tm: 0 to 0.8000%, Yb: 0 to 0.8000%, Lu: 0 to 0.8000%, and Sc: At least one X element selected from the group consisting of 0 to 0.8000%, Nb: 0-3.000%, Ti: 0 to 0.500%, Ta: 0 to 0.500%, V: 0 to
- the phosphorus contained in the phosphide containing the X element, the amount of P contained in the phosphide measured by the extraction residue method is 0.0003 atomic% or more with respect to the steel material, and the phosphorus is measured by the TEM replica method.
- Nb 0.003 to 3.000%, Ti: 0.005 to 0.500%, Ta: 0.001 to 0.500%, V: 0.001 to 1.00%, Cu: 0.001 to 3.00%, Ni: 0.001 to 60.00%, Cr: 0.001 to 30.00%, Mo: 0.001 to 5.00%, W: 0.001 to 2.00%, B: 0.0001-0.0200%, Co: 0.001 to 3.00%, Be: 0.0003 to 0.050%, Ag: 0.001 to 0.500%, Zr: 0.0001 to 0.5000%, Hf: 0.0001 to 0.5000%, Ca: 0.0001-0.0500%, Mg: 0.0001-0.0500%, At least one of La, Ce, Nd, Pm and Y: 0.0001 to 0.5000% in total, Sn: 0.001 to 0.300%, Sb: 0.001 to 0.300%, Te: 0.001 to 0.100%, Se: 0.001 to 0.100%, As: 0.001 to 0.050%, Bi:
- the steel material according to the embodiment of the present invention is based on mass%.
- the phosphorus contained in the phosphide containing the X element, the amount of P contained in the phosphide measured by the extraction residue method is 0.0003 atomic% or more with respect to the steel material, and the phosphorus is measured by the TEM replica method. It is characterized in that the average particle size of the compound is less than 100 nm. 0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] +0.
- the metallographic structure it is generally important to miniaturize the metallographic structure in order to improve the material properties required for steel materials, for example, low temperature toughness and / or to achieve both high strength and low temperature toughness.
- the recrystallization of austenite crystal grains is suppressed by controlling the end temperature at the time of hot rolling, more specifically, finish rolling of the steel material to a low temperature. Due to the suppression of recrystallization, the driving force of ferrite transformation is increased to generate more new crystals.
- the texture tends to develop in a specific direction by rolling, so that a metal structure showing high anisotropy can be obtained. Therefore, it may not be suitable for applications that require an isotropic metal structure, for example, applications that require high hole expandability such as undercarriage parts of automobiles.
- Recrystallization means that after plastic working by hot rolling or the like, the strain energy accumulated by the plastic working when held at a high temperature is released by diffusion accompanied by rearrangement of atomic positions, and new crystal grains are generated. It is a phenomenon that occurs. Therefore, the metal structure refined by recrystallization generally has less anisotropy and becomes an isotropic structure. Therefore, in applications where an isotropic metallographic structure is preferred, miniaturization by recrystallization is very advantageous.
- the use and control of pinned particles may be effective in suppressing the formation of coarse tissue.
- the present inventors have studied elements in steel that can be used as pinning particles for suppressing grain growth of a metal structure.
- the present inventors refer to the amounts of the elements of Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc (hereinafter, also referred to as "X element") thereof.
- X element also referred to as "X element”
- the effective amount of the element X is 0.0003% or more), and the specific element is reacted with P in the steel to form a relatively large and fine phosphate (that is, measured by the extraction residue method).
- the amount of P in the phosphonic acid is 0.0003 atomic% or more with respect to the steel material, and the average particle size measured by the TEM replica method is less than 100 nm). It has been found that the particles can be effectively functioned as pinning particles, and as a result, the grain growth of the metal structure can be remarkably suppressed.
- the above element X has the property of easily forming inclusions composed of oxides, nitrides and sulfides in combination with O (oxygen), N (nitrogen) and S (sulfur) existing in steel.
- O oxygen
- N nitrogen
- S sulfur
- the amount of the X element that can contribute to the reaction with P in the steel decreases, and a phosphide as a pinning particle is sufficiently formed. You will not be able to.
- the amount of the X element in consideration of such inclusions is calculated as the effective amount of the X element by the above formula 1 which will be described in detail later, and the effective amount is a certain amount or more, that is, 0.0003.
- the element X can be reacted with P in the steel to form a sufficient amount of phospholides to effectively function as pinning particles.
- the amount and size of such a phosphide are as described in detail later, and the amount of P in the phosphide measured by the extraction residue method is 0. It has been found that a higher pinning effect can be achieved by keeping the average particle size in the range of 0003 atomic% or more and the average particle size measured by the TEM replica method within the range of less than 100 nm. According to the present invention, such a pinning effect can be effectively applied regardless of whether or not the miniaturization of the metal structure is due to recrystallization.
- the micronization of the metal structure is due to recrystallization, specifically, the X element present in the recrystallized austenite during hot rolling reacts with P to become fine.
- the phosphite is precipitated, and the pinning effect of the phosphite suppresses the growth of recrystallized austenite grains.
- a steel material having an austenite metal structure has fine crystal grains, and a steel material having a martensite metal structure has fine so-called old austenite grains.
- the fine recrystallized austenite grains transform into a fine ferrite structure in the process of lowering the temperature after the completion of hot rolling, the metal structure containing an isotropic and fine ferrite structure is stably maintained. It becomes possible.
- the element X in the present invention easily combines with O, N and S to form inclusions as described above, and therefore it is generally difficult to secure a predetermined effective amount in steel. Under these circumstances, the pinning effect of the phosphide containing the X element has not been known so far. However, recent advances in refining technology have made it possible to reduce the content of elements such as O, N, and S, which are generally present in steel as impurities, to extremely low levels. It was possible to realize an effective amount of the X element within a predetermined range. Therefore, the pinning effect of the phosphide containing the X element was first clarified by the present inventors, and is extremely surprising and surprising.
- Carbon (C) is an element necessary for stabilizing hardness and / or ensuring strength. In order to sufficiently obtain these effects, the C content is 0.001% or more. The C content may be 0.005% or more, 0.010% or more, or 0.020% or more. On the other hand, if C is excessively contained, toughness, bendability and / or weldability may decrease. Therefore, the C content is 1.000% or less. The C content may be 0.800% or less, 0.600% or less, or 0.500% or less.
- Si is a deoxidizing element and is an element that also contributes to the improvement of strength. In order to sufficiently obtain these effects, the Si content is 0.01% or more. The Si content may be 0.05% or more, 0.10% or more, or 0.30% or more. On the other hand, if Si is excessively contained, the toughness may be lowered or surface quality defects called scale defects may occur. Therefore, the Si content is 3.00% or less. The Si content may be 2.00% or less, 1.00% or less, or 0.60% or less.
- Manganese (Mn) is an element effective for improving hardenability and / or strength, and is also an effective austenite stabilizing element. In order to sufficiently obtain these effects, the Mn content is 0.10% or more. The Mn content may be 0.50% or more, 0.70% or more, or 1.00% or more. On the other hand, if Mn is excessively contained, MnS harmful to toughness may be generated or the oxidation resistance may be lowered. Therefore, the Mn content is 4.50% or less. The Mn content may be 4.00% or less, 3.50% or less, or 3.00% or less.
- Phosphorus (P) is an element that is generally mixed in the manufacturing process, but in the embodiment of the present invention, it effectively functions as an element constituting a phosphide, which is a pinning particle, in suppressing grain growth.
- the P content is 0.0005% or more.
- the P content may be 0.001% or more, 0.002% or more, 0.003% or more, 0.005% or more, or 0.007% or more.
- the P content is 0.300% or less.
- the P content may be 0.100% or less, 0.050% or less, or 0.030% or less.
- S 0.0300% or less
- Sulfur (S) is an element mixed in the manufacturing process, and is preferable from the viewpoint of reducing inclusions formed with the X element according to the embodiment of the present invention, so that the S content is 0%. There may be. However, in order to reduce the S content to less than 0.0001%, it takes time for refining, which leads to a decrease in productivity. Therefore, the S content may be 0.0001% or more, 0.0005% or more, or 0.0010% or more. On the other hand, if S is excessively contained, the effective amount of the X element may decrease and the toughness may decrease. Therefore, the S content is 0.0300% or less.
- the S content is preferably 0.0100% or less, more preferably 0.0050% or less, and most preferably 0.0030% or less.
- Aluminum (Al) is a deoxidizing element and is also an effective element for improving corrosion resistance and / or heat resistance.
- the Al content is 0.001% or more.
- the Al content may be 0.010% or more, 0.100% or more, or 0.200% or more.
- the Al content may be 1.000% or more, 2.000% or more, or 3.000% or more.
- the Al content is 5.000% or less.
- the Al content may be 4.500% or less, 4000% or less, or 3.500% or less.
- the Al content may be 1.500% or less, 1.000% or less, or 0.300% or less.
- N Nitrogen (N) is an element mixed in the manufacturing process, and is preferable from the viewpoint of reducing inclusions formed with the X element according to the embodiment of the present invention, so that the N content is 0%. There may be. However, in order to reduce the N content to less than 0.0001%, it takes time for refining, which leads to a decrease in productivity. Therefore, the N content may be 0.0001% or more, 0.0005% or more, or 0.0010% or more. On the other hand, N is also an element effective for stabilizing austenite, and may be intentionally contained if necessary. In this case, the N content is preferably 0.0100% or more, and may be 0.0200% or more and 0.0500% or more.
- the N content is 0.2000% or less.
- the N content may be 0.1500% or less, 0.1000% or less, or 0.0800% or less.
- Oxygen (O) is an element mixed in the manufacturing process, and is preferable from the viewpoint of reducing inclusions formed with the X element according to the embodiment of the present invention, so that the O content is 0%. There may be. However, in order to reduce the O content to less than 0.0001%, it takes time for refining, which leads to a decrease in productivity. Therefore, the O content may be 0.0001% or more, 0.0005% or more, or 0.0010% or more. On the other hand, if O is excessively contained, coarse inclusions may be formed, the effective amount of the X element may be lowered, and the formability and / or toughness of the steel material may be lowered. Therefore, the O content is 0.0100% or less. The O content may be 0.0080% or less, 0.0060% or less, or 0.0040% or less.
- the X element may be used alone or in any specific combination of two or more of the above elements. Further, the element X may be present in an amount satisfying Equation 1, which will be described in detail later, and the lower limit thereof is not particularly limited. However, for example, the content of each X element or the total content may be 0.0010% or more, preferably 0.0050% or more, more preferably 0.0150% or more, and even more. It is preferably 0.0300% or more, and most preferably 0.0500% or more. On the other hand, even if the X element is excessively contained, the effect is saturated, and therefore, if the X element is contained in the steel material more than necessary, the manufacturing cost may increase.
- each X element is 0.8000% or less, for example, 0.7000% or less, 0.6000% or less, 0.5000% or less, 0.4000% or less, or 0.3000% or less. May be good.
- the total content of element X is 9.6000% or less, for example, 6.00% or less, 5.0000% or less, 4.00% or less, 2.0000% or less, 1.0000% or less or 0. It may be 5000% or less.
- the steel material may contain one or more of the following optional elements, if necessary.
- the steel material has Nb: 0 to 3.000%, Ti: 0 to 0.500%, Ta: 0 to 0.500%, V: 0 to 1.00%, Cu: 0 to 3.00%, Ni: 0 to 60.00%, Cr: 0 to 30.00%, Mo: 0 to 5.00%, W: 0 to 2.00%, B: 0 to 0.0200%, Co: 0 to 3 It may contain one or more of 0.00%, Be: 0 to 0.050%, and Ag: 0 to 0.500%.
- the steel materials include Zr: 0 to 0.5000%, Hf: 0 to 0.5000%, Ca: 0 to 0.0500%, Mg: 0 to 0.0500%, and La, Ce, Nd, Pm and At least one of Y: One or more of 0 to 0.5000% in total may be contained. Further, the steel material may contain one or two of Sn: 0 to 0.300% and Sb: 0 to 0.300%. The steel materials are Te: 0 to 0.100%, Se: 0 to 0.100%, As: 0 to 0.050%, Bi: 0 to 0.500%, and Pb: 0 to 0.500%. One or more of them may be contained. Hereinafter, these optional elements will be described in detail.
- Niobium (Nb) is an element that contributes to strengthening precipitation and suppressing recrystallization.
- the Nb content may be 0%, but in order to obtain these effects, the Nb content is preferably 0.003% or more.
- the Nb content may be 0.005% or more or 0.010% or more.
- the Nb content may be 1.000% or more or 1.500% or more from the viewpoint of sufficiently strengthening precipitation.
- the Nb content is 3.000% or less.
- the Nb content may be 2.800% or less, 2.500% or less, or 2.000% or less.
- the Nb content is preferably 0.100% or less, 0.080% or less, 0.050% or less, or 0.030. It may be less than or equal to%.
- Titanium (Ti) is an element that contributes to improving the strength of steel materials by strengthening precipitation.
- the Ti content may be 0%, but in order to obtain such an effect, the Ti content is preferably 0.005% or more.
- the Ti content may be 0.010% or more, 0.050% or more, or 0.080% or more.
- the Ti content is 0.500% or less.
- the Ti content may be 0.300% or less, 0.200% or less, or 0.100% or less.
- Tantalum (Ta) is an element effective in controlling the morphology of carbides and increasing their strength.
- the Ta content may be 0%, but in order to obtain these effects, the Ta content is preferably 0.001% or more.
- the Ta content may be 0.005% or more, 0.010% or more, or 0.050% or more.
- the Ta content is 0.500% or less.
- the Ta content may be 0.300% or less, 0.100% or less, or 0.080% or less.
- Vanadium (V) is an element that contributes to improving the strength of steel materials by strengthening precipitation.
- the V content may be 0%, but in order to obtain such an effect, the V content is preferably 0.001% or more.
- the V content may be 0.01% or more, 0.02% or more, 0.05% or more, or 0.10% or more.
- the V content is 1.00% or less.
- the V content may be 0.80% or less, 0.60% or less, or 0.50% or less.
- Copper (Cu) is an element that contributes to the improvement of strength and / or corrosion resistance.
- the Cu content may be 0%, but in order to obtain these effects, the Cu content is preferably 0.001% or more.
- the Cu content may be 0.01% or more, 0.10% or more, 0.15% or more, 0.20% or more, or 0.30% or more.
- the Cu content is 3.00% or less.
- the Cu content may be 2.00% or less, 1.50% or less, 1.00% or less, or 0.50% or less.
- Nickel (Ni) is an element that contributes to the improvement of strength and / or heat resistance, and is also an effective austenite stabilizing element.
- the Ni content may be 0%, but in order to obtain these effects, the Ni content is preferably 0.001% or more.
- the Ni content may be 0.01% or more, 0.10% or more, 0.50% or more, 0.70% or more, 1.00% or more, or 3.00% or more.
- the Ni content may be 30.00% or more, 35.00% or more, or 40.00% or more.
- the deformation resistance during hot working increases in addition to the increase in alloy cost, which may increase the equipment load.
- the Ni content is 60.00% or less.
- the Ni content may be 55.00% or less or 50.00% or less.
- the Ni content is 15.00% or less, 10.00% or less, 6.00% or less, or 4.00% or less. You may.
- Chromium (Cr) is an element that contributes to the improvement of strength and / or corrosion resistance.
- the Cr content may be 0%, but in order to obtain these effects, the Cr content is preferably 0.001% or more.
- the Cr content may be 0.01% or more, 0.05% or more, 0.10% or more, or 0.50% or more.
- the Cr content may be 10.00% or more, 12.00% or more, or 15.00% or more.
- the Cr content is 30.00% or less.
- the Cr content may be 28.00% or less, 25.00% or less, or 20.00% or less.
- the Cr content may be 10.00% or less, 9.00% or less, or 7.50% or less.
- Molybdenum is an element that enhances the hardenability of steel and contributes to the improvement of strength, and is also an element that contributes to the improvement of corrosion resistance.
- the Mo content may be 0%, but in order to obtain these effects, the Mo content is preferably 0.001% or more.
- the Mo content may be 0.01% or more, 0.02% or more, 0.50% or more, or 1.00% or more.
- Mo content is 5.00% or less.
- the Mo content may be 4.50% or less, 4.00% or less, 3.00 or less, or 1.50% or less.
- Tungsten is an element that enhances the hardenability of steel and contributes to the improvement of strength.
- the W content may be 0%, but in order to obtain such an effect, the W content is preferably 0.001% or more.
- the W content may be 0.01% or more, 0.02% or more, 0.05% or more, 0.10% or more, or 0.50% or more.
- the W content is 2.00% or less.
- the W content may be 1.80% or less, 1.50% or less, or 1.00% or less.
- B is an element that contributes to the improvement of strength.
- the B content may be 0%, but in order to obtain such an effect, the B content is preferably 0.0001% or more.
- the B content may be 0.0003% or more, 0.0005% or more, or 0.0007% or more.
- the B content is 0.0200% or less.
- the B content may be 0.0100% or less, 0.0050% or less, 0.0030% or less, or 0.0020% or less.
- Co is an element that contributes to the improvement of hardenability and / or heat resistance.
- the Co content may be 0%, but in order to obtain these effects, the Co content is preferably 0.001% or more.
- the Co content may be 0.01% or more, 0.02% or more, 0.05% or more, 0.10% or more, or 0.50% or more.
- the Co content is 3.00% or less.
- the Co content may be 2.50% or less, 2.00% or less, 1.50% or less, or 0.80% or less.
- Beryllium (Be) is an element effective for increasing the strength of the base metal and refining the structure.
- the Be content may be 0%, but in order to obtain such an effect, the Be content is preferably 0.0003% or more.
- the Be content may be 0.0005% or more, 0.001% or more, or 0.010% or more.
- the Be content is 0.050% or less.
- the Be content may be 0.040% or less, 0.030% or less, or 0.020% or less.
- Silver (Ag) is an element effective for increasing the strength of the base material and refining the structure.
- the Ag content may be 0%, but in order to obtain such an effect, the Ag content is preferably 0.001% or more.
- the Ag content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more.
- the Ag content is 0.500% or less.
- the Ag content may be 0.400% or less, 0.300% or less, or 0.200% or less.
- Zirconium (Zr) is an element that can control the morphology of sulfides.
- the Zr content may be 0%, but in order to obtain such an effect, the Zr content is preferably 0.0001% or more.
- the Zr content is 0.5000% or less.
- Hafnium (Hf) is an element that can control the morphology of sulfides.
- the Hf content may be 0%, but in order to obtain such an effect, the Hf content is preferably 0.0001% or more.
- the Hf content is 0.5000% or less.
- Ca 0-0.0500%
- Ca is an element that can control the morphology of sulfides.
- the Ca content may be 0%, but in order to obtain such an effect, the Ca content is preferably 0.0001% or more.
- the Ca content is 0.0500% or less.
- Magnesium (Mg) is an element that can control the morphology of sulfides.
- the Mg content may be 0%, but in order to obtain such an effect, the Mg content is preferably 0.0001% or more.
- the Mg content may be greater than 0.0015%, greater than 0.0016%, greater than or equal to 0.0018% or greater than or equal to 0.0020%.
- the Mg content is 0.0500% or less.
- the Mg content may be 0.0400% or less, 0.0300% or less, or 0.0200% or less.
- La, Ce, Nd, Pm and Y 0 to 0.5000% in total
- Lanthanum (La), cerium (Ce), neodymium (Nd), promethium (Pm) and yttrium (Y) are elements that can control the morphology of sulfides, similar to Ca and Mg.
- the total content of at least one of La, Ce, Nd, Pm and Y may be 0%, but is preferably 0.0001% or more in order to obtain such an effect.
- the total content of at least one of La, Ce, Nd, Pm and Y may be 0.0002% or more, 0.0003% or more or 0.0004% or more.
- the total content of at least one of La, Ce, Nd, Pm and Y is 0.5000% or less, even if it is 0.4000% or less, 0.3000% or less or 0.2000% or less. good.
- Tin (Sn) is an element effective for improving corrosion resistance.
- the Sn content may be 0%, but in order to obtain such an effect, the Sn content is preferably 0.001% or more.
- the Sn content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more.
- the Sn content is 0.300% or less.
- the Sn content may be 0.250% or less, 0.200% or less, or 0.150% or less.
- Antimony (Sb) is an element effective for improving corrosion resistance like Sn, and the effect can be increased by including it in combination with Sn.
- the Sb content may be 0%, but in order to obtain the effect of improving the corrosion resistance, the Sb content is preferably 0.001% or more.
- the Sb content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more.
- excessive content of Sb may lead to a decrease in toughness, particularly low temperature toughness. Therefore, the Sb content is 0.300% or less.
- the Sb content may be 0.250% or less, 0.200% or less, or 0.150% or less.
- Tellurium is an element effective for improving the machinability of steel because it forms a low melting point compound with Mn, S and the like to enhance the lubricating effect.
- the Te content may be 0%, but in order to obtain such an effect, the Te content is preferably 0.001% or more.
- the Te content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.040% or more.
- the Te content is 0.100% or less.
- the Te content may be 0.090% or less, 0.080% or less, or 0.070% or less.
- Selenium (Se) is an effective element for improving the machinability of steel because the selenium produced in the steel changes the shear-plastic deformation of the work material and the chips are easily crushed. ..
- the Se content may be 0%, but in order to obtain such an effect, the Se content is preferably 0.001% or more.
- the Se content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.040% or more.
- the Se content is 0.100% or less.
- the Se content may be 0.090% or less, 0.080% or less, or 0.070% or less.
- Arsenic (As) is an element effective in improving the machinability of steel.
- the As content may be 0%, but in order to obtain such an effect, the As content is preferably 0.001% or more.
- the As content may be 0.005% or more or 0.010% or more.
- the As content is 0.050% or less.
- the As content may be 0.040% or less, 0.030% or less, or 0.020% or less.
- Bismuth (Bi) is an element effective in improving the machinability of steel.
- the Bi content may be 0%, but in order to obtain such an effect, the Bi content is preferably 0.001% or more.
- the Bi content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more.
- the Bi content is 0.500% or less.
- the Bi content may be 0.400% or less, 0.300% or less, or 0.200% or less.
- Pb 0 to 0.500%
- Lead (Pb) is an element effective for improving the machinability of steel because it melts when the temperature rises due to cutting and promotes the growth of cracks.
- the Pb content may be 0%, but in order to obtain such an effect, the Pb content is preferably 0.001% or more.
- the Pb content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more.
- the Pb content is 0.500% or less.
- the Pb content may be 0.400% or less, 0.300% or less, or 0.200% or less.
- the balance other than the above elements consists of Fe and impurities.
- Impurities are components that are mixed in by various factors in the manufacturing process, including raw materials such as ore and scrap, when steel materials are industrially manufactured.
- the effective amount of the X element consisting of Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc can be determined by the left side of the following formula 1. , And its value shall satisfy the following equation 1. 0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] +0.
- the effective amount of the X element By making the effective amount of the X element satisfy the above formula 1, it is possible to react the X element existing in austenite with P in the steel to form a phosphide, and such a phosphide can be formed. It is possible to suppress the grain growth of the metal structure due to the formation of the metal structure. More specifically, these X elements (hereinafter, also simply referred to as “X”) are combined with O (oxygen), N (nitrogen) and S (sulfur) present in the steel to form an oxide (X 2 O). 3 ), tend to form inclusions consisting of nitrides (XN) and sulfides (XS). Once the inclusions are formed, at least the X element in these inclusions cannot contribute to the reaction with P. Therefore, in order to promote the reaction with P and form a phosphide, which is a pinning particle, it is necessary to increase the amount of element X that can form a phosphide in austenite without forming inclusions
- the amount of element X that can form a phosphide is the amount of element X contained in the steel minus the maximum amount that can be consumed to form inclusions (oxides, nitrides and sulfides). It is possible to estimate by. Therefore, in the embodiment of the present invention, the amount of X element effective for forming the phosphide estimated in this way (that is, "effective amount of X element") is specifically determined by the following formula A. Defined.
- Effective amount of X [atomic%] ⁇ (M [Fe] / M [X] ) ⁇ [X]-(M [Fe] / M [O] ) ⁇ [O] ⁇ 2 / 3- (M [Fe ] ] / M [N] ) x [N]-(M [Fe] / M [S] ) x [S] ... Equation A
- X represents each X element of Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc
- M [X] is the atomic weight of the X element, M [Fe].
- M [O] is the atomic weight of O
- M [N] is the atomic weight of N
- M [S] is the atomic weight of S
- [X], [O], [N] and [S] are.
- Each is the content [mass%] of the corresponding element, and is 0 when the element is not contained.
- the steel material according to the embodiment of the present invention contains various alloying elements, the steel material as a whole is almost composed of Fe or is an optional element.
- the steel material is almost composed of Ni and / or Cr in addition to Fe. Is.
- the atomic weights of Ni and Cr are equivalent to the atomic weights of Fe.
- each X element of Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc.
- the atomic% of is obtained by multiplying the content [mass%] of each X element by the ratio of the atomic weight of Fe to the atomic weight of each X element, that is, (M [Fe] / M [X] ) ⁇ . It can be calculated by [X].
- Effective amount of X [atomic%] ⁇ (M [Fe] / M [X] ) ⁇ [X]-(M [Fe] / M [O] ) ⁇ [O] ⁇ 2 / 3- (M [Fe ] ] / M [N] ) x [N]-(M [Fe] / M [S] ) x [S] ... Equation A
- the atomic weights of Fe, O, N and S and each X element are Fe: 55.845, O: 15.9994, N: 14.0069, S: 32.068, Pr: 140.908, Sm, respectively. : 150.36, Eu: 151.964, Gd: 157.25, Tb: 158.925, Dy: 162.500, Ho: 164.930, Er: 167.259, Tm: 168.934, Yb: 173 .045, Lu: 174.967, Sc: 44.9559. Therefore, by substituting the atomic weight of each element into the above formula A and arranging it, the effective amount of the element X in terms of atomic% can be approximately expressed by the following formula B.
- Effective amount 0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] ] +0.33 [Tm] +0.32 [Yb] +0.32 [Lu] +1.24 [Sc] -2.33 [O] -3.99 [N] -1.74 [S] ... B
- [O], [N], and [S] are the content [mass%] of each element, and are 0 when the element is not contained.
- the effective amount of the X element determined by the above formula B is 0.0003% or more, that is, at least satisfy the following formula 1. 0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] +0. 33 [Tm] +0.32 [Yb] +0.32 [Lu] +1.24 [Sc] -2.33 [O] -3.99 [N] -1.74 [S] ⁇ 0.0003 ...
- the effective amount of the X element may be, for example, 0.0005% or more or 0.0007% or more, preferably 0.0010% or more, more preferably 0.0015% or more, still more preferably 0.0030%.
- the above is most preferably 0.0050% or more or 0.0100% or more.
- the upper limit of the effective amount of the X element is not particularly limited, but even if the effective amount of the X element is excessively increased, the effect is saturated and the manufacturing cost increases (alloy cost due to the increase in the content of the X element).
- the effective amount of element X is preferably 2.000% or less, for example, 1.8000% or less, 1.5000% or less, 1.2000% or less, 1.000% or less, or 0.8000% or less. You may.
- the amount of P contained in the phosphide measured by the extraction residue method is 0.0003 atomic% or more with respect to the steel material
- element X needs to react with P to form a phosphide and be present in the steel in an amount capable of the phosphide effectively functioning as pinning particles.
- a phosphonic acid substance containing an element X is present in the steel, and the amount of P contained in the phosphor compound measured by the extraction residue method is required to be 0.0003 atomic% or more with respect to the steel material.
- the phosphonic acid product effectively functions as a pinning particle, and the grain growth of the metal structure can be remarkably suppressed.
- the above amount of P is preferably 0.0005 atom% or more, more preferably 0.0010 atom% or more, still more preferably 0.0030 atom% or more, most preferably 0.0050 atom% or more or 0.0100 atom. % Or more.
- the upper limit of the P amount is not particularly limited, but even if the P amount is excessively increased, the effect is saturated and the production cost is increased (the alloy cost due to the increase in the content of the X element for forming the phosphite). It is not always preferable because it causes an increase and / or an increase in the refining cost for O, N and S).
- the amount of P is preferably 0.5000 atom% or less, for example, 0.4000 atom% or less, 0.3000 atom% or less, 0.2000 atom% or less, 0.1500 atom% or less, or 0.1000 atom. It may be less than or equal to%.
- the amount of P contained in the phosphide is determined as follows by the extraction residue method. First, a sample containing a depth of 0.5 mm from the surface of the steel material collected from the steel material is electrolyzed with 1 g or more of the steel material by constant current electrolysis, and then filtered using a membrane filter having a pore size of 0.2 ⁇ m to form a precipitate (phosphide). Is separated. Next, the separated precipitate was decomposed with a solution such as nitrate (HNO 3 ), and then the obtained residue was measured by ICP-MS (inductively coupled plasma mass spectrometer). The amount of P present as is obtained. Finally, the ratio (atomic%) of the amount of P contained in the phosphide to the whole steel material is determined from the amount of P and the specific amount of the electrolyzed steel material.
- the average particle size of the phosphide is preferably 90 nm or less, more preferably 80 nm or less, even more preferably 60 nm or less, and most preferably 50 nm or less or 40 nm or less.
- the lower limit of the average particle size of the phosphide is not particularly limited, but may be, for example, 5 nm or more, and may be 8 nm or more, 10 nm or more, 15 nm or more, 20 nm or more, or 25 nm or more.
- the average particle size of the phosphide is determined by the TEM replica method as follows. First, a test piece for observing precipitates is collected from the steel material, the cross section is polished parallel to the rolling direction and at a depth of 0.5 mm from the surface of the steel material, and then etching is performed by the SPEED method (selective constant potential electrolytic etching method). Then, the precipitate is extracted into a carbon film by the blank replica method and held on the Cu mesh.
- the prepared carbon extraction replica sample was analyzed by EDS (energy dispersion type X-ray spectroscope) to identify the phosphonic acid, and TEM (transmission electron microscope, acceleration voltage 200 kV) was applied to the phosphonic acid.
- EDS energy dispersion type X-ray spectroscope
- TEM transmission electron microscope, acceleration voltage 200 kV
- the steel material according to the embodiment of the present invention may be any steel material on which a phosphide containing an element X is formed, and is not particularly limited.
- the steel material according to the embodiment of the present invention includes, for example, thick steel plates and thin steel plates which are steel materials after hot rolling, as well as steel bars, wire rods, shaped steels, steel pipes, and the like.
- the steel material according to the embodiment of the present invention can be manufactured by any suitable method known to those skilled in the art, depending on the form of the final product and the like.
- the manufacturing method includes a step generally applied when manufacturing the thick steel plate, for example, a step of casting a slab having the chemical composition described above, and casting. It includes a step of hot rolling the slab and a step of cooling the obtained rolled material, and may further include heat treatment such as a quenching step and a tempering step, if necessary.
- the steel material manufacturing process according to the embodiment of the present invention may be a thermal processing control process (TMCP) that combines controlled rolling and accelerated cooling.
- TMCP thermal processing control process
- the manufacturing method includes a step generally applied when manufacturing the thin steel plate, for example, a step of casting a slab having the chemical composition described above, and casting. It may further include a step of hot rolling the slab, a step of cooling and winding the obtained rolled material, a cold rolling step, a baking step and the like, if necessary.
- a method for manufacturing steel bars and other steel materials also includes a process generally applied when manufacturing steel bars and other steel materials, for example, a steelmaking process for forming molten steel having the chemical composition described above. It includes a step of casting slabs, billets, blooms, etc.
- the thermal history in the hot rolling process is important for the formation of phosphide.
- the temperature and time range (phosphorization nose) at which the phosphite of each X element is precipitated is determined in advance, and the hotness is determined.
- the thermal history of the rolling process may be guided within this temperature and time range (ie, within the precipitation nose of the phosphite). It will be described in more detail below with reference to the drawings.
- FIG. 1 is a schematic diagram showing a precipitation nose of a phosphide containing element X.
- FIG. 1 is a schematic diagram as described above, and the curve of the precipitation nose actually changes depending on the X element or the like specifically used.
- the precipitation nose of the phosphide shifts to the short-time side.
- the thermal history in the hot rolling process passes through the precipitation nose, element X and P in the steel can be reacted to form a phosphide.
- strain is applied at a high temperature of 1100 ° C.
- the mixture is held in the range of 950 to 1100 ° C. for a short time of about 10 seconds and then cooled.
- the heat history in the hot rolling process does not pass through the precipitation nose and phosphide cannot be formed.
- retention includes a case where the temperature gradually decreases due to cooling, air cooling, or the like within the above temperature range.
- the hot rolling process is a process from heating the slab, billet, and bloom to the end of rough rolling and / or finish rolling.
- the specific thermal history in this step is not particularly limited because it changes depending on the type of element X and the like, but the thermal history is, for example, during rough rolling and / or finish rolling, or during rough rolling and / or rough rolling and /. Alternatively, it includes holding for 30 seconds or more in a temperature range of 900 to 1100 ° C., preferably 950 to 1100 ° C. after finish rolling. Alternatively, the thermal history may include holding at 950 to 1100 ° C., preferably 980 to 1020 ° C. for 1000 seconds or longer before adding strain in hot rolling.
- phosphide is formed before strain is applied by hot rolling.
- the upper limit of the holding time is not particularly limited, but may be, for example, 15,000 seconds or less or 12,000 seconds or less.
- the thermal history during rough rolling and / or finish rolling, or after rough rolling and / or finish rolling.
- the Ac3 point is the temperature at which the transformation from ferrite to austenite is completed during heating.
- the austenite particle size when the test piece is heated to 950 ° C. at a heating rate of 20 ° C./sec and held for 10 seconds is D1
- the test piece is heated to 1050 ° C. at a heating rate of 20 ° C./sec.
- the austenite particle size when held for 10 seconds was defined as D2.
- Table 2 below also shows the chemical composition obtained by analyzing the sample collected from each of the obtained steel materials, the amount of P contained in the phosphide in each steel material (precipitated P amount), and the average particle size of the phosphide.
- the amount of P contained in the phosphide and the average particle size of the phosphide were measured by the following methods.
- the amount of P contained in the phosphide was determined as follows by the extraction residue method. First, a sample containing a depth of 0.5 mm from the surface of the steel material collected from the steel material is subjected to constant current electrolysis under the conditions of 10% acetylacetone-1% tetramethylammonium chloride-methanol solution at 500 mmA and 2 hours or more to obtain 1 g or more of the steel material. Was electrolyzed and then filtered using a membrane filter having a pore size of 0.2 ⁇ m to separate precipitates (phosphide).
- the separated precipitate was decomposed with a solution in which nitric acid (HNO 3 ) and perchloric acid (HClO 4 ) were mixed at a ratio of 2: 1 and the obtained residue was then subjected to ICP-MS (inductively coupled plasma mass spectrometer). ) was used to obtain the amount of P present as a phosphate precipitated in the steel material. Finally, the ratio (atomic%) of the amount of P contained in the phosphide to the whole steel material was determined from the amount of P and the specific amount of the electrolyzed steel material.
- the average particle size of the phosphide was determined by the TEM replica method as follows. First, a test piece for observing precipitates is collected from the steel material, and the cross section parallel to the rolling direction and at a depth of 0.5 mm from the steel material surface is polished (mirror-polished with emery paper or diamond paste, and then the polished surface is polished. Finish polishing with alumina abrasive grains), then etching by SPEED method (selective constant potential electrolytic etching method) (electropolishing solution: 10% acetylacetone-1% tetramethylammonium chloride-methanol, electrolytic polishing conditions: -100 mV vs.
- SPEED method selective constant potential electrolytic etching method
- Comparative Examples 84 to 91 the effective amount of the X element composed of Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc was low, so that the steel material was used. The P inside could not be precipitated as a phospholide, and as a result, the grain growth of the metal structure could not be suppressed.
- Comparative Example 92 the effective amount of the X element was higher than 0.0003%, and therefore satisfied Equation 1, but the thermal history in the hot rolling step was not appropriate, so that phosphorus was used. The phosphide could not be precipitated, and as a result, the grain growth of the metal structure could not be suppressed.
- the effective amount of element X is 0.0003% or more, and the amount of P contained in the phosphide and the average particle size of the phosphide are appropriate. By doing so, the grain growth of the metal structure could be sufficiently suppressed.
- the steel material according to the embodiment of the present invention includes steel materials after hot rolling in which a phosphonic acid containing an element X is formed, for example, thick steel plates used for bridges, construction, shipbuilding, pressure vessels, and the like, automobiles, and the like. It includes thin steel plates used for applications such as home appliances, as well as steel bars, wire rods, shaped steels, steel pipes, and the like.
- the steel material according to the embodiment of the present invention is applied to these materials, the grain growth of the metal structure is suppressed, and therefore the fine metal structure is stably maintained. Therefore, for example, high strength and low temperature toughness. It is possible to achieve both of the contradictory characteristics of.
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Abstract
Provided is a steel material with a predetermined chemical composition satisfying 0.40[Pr] + 0.37[Sm] + 0.37[Eu] + 0.36[Gd] + 0.35[Tb] + 0.34[Dy] + 0.34[Ho] + 0.33[Er] + 0.33[Tm] + 0.32[Yb] + 0.32[Lu] + 1.24[Sc] - 2.33[O] - 3.99[N] - 1.74[S] ≥ 0.0003 (in the formula, [Pr], [Sm], [Eu], [Gd], [Tb], [Dy], [Ho], [Er], [Tm], [Yb], [Lu], [Sc], [O], [N], and [S] represent the content [mass%] of each element), in which the amount of P included in phosphide compounds as measured by an extraction residue method is 0.0003 at% or more with respect to the steel material and the average particle size of phosphides as measured by the TEM replica method is less than 100 nm.
Description
本発明は、鋼材に関する。
The present invention relates to steel materials.
リン（Ｐ）は、鋼中の特定の箇所、例えば、デンドライト樹間、結晶粒界に濃化して、鋼材の靭性、延性、耐食性及び溶接性などの特性を低下させる場合があることが知られている。鋼材の特性を向上させるためには、鋼中の固溶Ｐ量を低減することが重要であるが、Ｐ含有量を極端に低減させるには製造コストの上昇が避けられない。そのため、鋼中にリン化物を生成させてＰを無害化する方法が提案されている（例えば、特許文献１～特許文献３、参照）。
It is known that phosphorus (P) may be concentrated at specific points in the steel, for example, between dendrite trees and grain boundaries, and may reduce the toughness, ductility, corrosion resistance and weldability of the steel material. ing. In order to improve the characteristics of the steel material, it is important to reduce the amount of solid solution P in the steel, but in order to extremely reduce the P content, an increase in manufacturing cost is unavoidable. Therefore, a method of forming a phosphide in steel to detoxify P has been proposed (see, for example, Patent Documents 1 to 3).
特許文献１では、ＲＥＭを含有し、生成されるリン化物を微細化することにより、靭性を向上させることが可能な炭素鋼鋳片が記載されている。また、特許文献１では、界面活性元素であるＴｅを含有する鋼は、凝固組織が微細になり、デンドライト樹脂間に供給されるＰ量が少なくなり、リン化物が微細化され、炭素鋼鋳片の靭性劣化が抑制されることが教示されている。
Patent Document 1 describes a carbon steel slab containing REM and capable of improving toughness by refining the produced phosphide. Further, in Patent Document 1, the steel containing Te, which is a surface active element, has a fine solidified structure, a small amount of P supplied between the dendrite resins, a fine phosphide, and carbon steel slabs. It is taught that the deterioration of toughness of steel is suppressed.
特許文献２では、過度なＰの低下、微量元素やＳｉ、Ｍｏ等の合金化によらず、深絞り加工後に熱処理が施されて顕在化する二次加工脆性を改善した、高純度フェライト系ステンレス鋼板が記載されている。また、特許文献２では、二次加工脆性を改善するには、予めＰを化合物として析出させて鋼中の固溶Ｐを低減して、Ｐの粒界偏析を遅延させることが有効であること、微細なリン化物は結晶粒界に析出した場合でも、割れの起点としての作用よりもＰの粒界偏析を遅延させる効果が大きいことが教示されている。
In Patent Document 2, high-purity ferritic stainless steel with improved secondary processing brittleness that is manifested by heat treatment after deep drawing without excessive reduction of P and alloying of trace elements, Si, Mo, etc. Steel plates are listed. Further, in Patent Document 2, in order to improve the secondary processing brittleness, it is effective to precipitate P as a compound in advance to reduce the solid melt P in the steel and delay the grain boundary segregation of P. It is taught that even when the fine phospholides are deposited at the grain boundaries, the effect of delaying the segregation of the grain boundaries of P is greater than the action as the starting point of cracking.
特許文献３では、Ｐを残存させ、積極的に粗大なＴｉ系析出物として析出させ、Ｐを無害化し、加工性、降伏強度などの特性を改善したステンレス鋼が記載されている。また、特許文献３では、Ｔｉ系炭化物やＴｉ系リン化物を粗大化させて固溶Ｃや固溶Ｐを無害化し、Ｔｉ系析出物のピンニング効果を利用して鋼板の結晶粒の粗大化を制御し、延性、リジング、機械特性の異方性を改善することが教示されている。
Patent Document 3 describes a stainless steel in which P remains, positively precipitates as a coarse Ti-based precipitate, detoxifies P, and has improved properties such as workability and yield strength. Further, in Patent Document 3, Ti-based carbides and Ti-based phosphates are coarsened to detoxify solid-dissolved C and solid-dissolved P, and the pinning effect of Ti-based precipitates is used to coarsen the crystal grains of the steel plate. It is taught to control and improve ductility, rigging, and anisotropy of mechanical properties.
鋼中に存在する微細な粒子は、金属組織の粒成長を抑制するピン止め粒子として利用されることがある。一般に、溶接熱影響部の金属組織を微細化するピン止め粒子として、窒化物、酸化物、硫化物などが知られているが、ＲＥＭリン化物をピン止め粒子として活用した炭素鋼鋳片が提案されている（例えば、特許文献４、参照）。
The fine particles present in the steel may be used as pinning particles that suppress the grain growth of the metal structure. Generally, nitrides, oxides, sulfides, etc. are known as pinning particles for refining the metal structure of the weld heat-affected zone, but a carbon steel slab utilizing REM phosphate as pinning particles is proposed. (See, for example, Patent Document 4,).
特許文献４では、ＲＥＭを含有する炭素鋼鋳片において、介在物をピン止め粒子として活用することにより、溶接熱影響部の靭性を向上させることが可能な炭素鋼鋳片が記載されている。また、特許文献４では、介在物をピン止め粒子として活用するためには、サブミクロンオーダーの粒子を多量に生成させることが必要であること、溶鋼中でＺｒＳを生成させて、凝固後に鋳片表層部と中心部との温度差を利用して圧下することにより、ＺｒＳを析出核としてＲＥＭリン化物が析出することが教示されている。
Patent Document 4 describes a carbon steel slab containing REM, which can improve the toughness of the weld heat-affected zone by utilizing inclusions as pinning particles. Further, in Patent Document 4, in order to utilize inclusions as pinning particles, it is necessary to generate a large amount of particles on the order of submicrons, and ZrS is generated in molten steel to generate slabs after solidification. It is taught that REM phosphide is deposited with ZrS as a precipitation nucleus by reducing the pressure using the temperature difference between the surface layer portion and the central portion.
上記のように、従来技術では、鋼材の特性を低下させる場合があるＰをリン化物として析出させて無害化したり、またこのようなリン化物をピン止め粒子として活用したりすることが提案されている。しかしながら、従来、リン化物を金属組織の粒成長抑制に利用することは容易ではなく、実際、特許文献４に記載の発明においても、ピン止め粒子として利用するリン化物を析出させるためにＺｒＳ析出核の生成を必要としている。本発明は、このような実情に鑑みてなされたものであり、その目的とするところは、新規な構成により、金属組織の粒成長を抑制可能な鋼材を提供することにある。
As described above, in the prior art, it has been proposed to precipitate P as a phosphide, which may deteriorate the properties of steel materials, to make it harmless, or to utilize such a phosphide as pinning particles. There is. However, conventionally, it is not easy to use a phosphide to suppress grain growth of a metal structure, and in fact, even in the invention described in Patent Document 4, a ZrS precipitation nucleus is used to precipitate a phosphide to be used as a pinning particle. Needs to be generated. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a steel material capable of suppressing grain growth of a metal structure by a novel configuration.
本発明者らは、上記目的を達成するために検討を行った結果、特定元素の量を一定量以上確保するとともに、当該特定元素をリンと反応させて得られたリン化物をピン止め粒子として利用することで金属組織の粒成長を抑制することができることを見出し、本発明を完成させた。
As a result of studies to achieve the above object, the present inventors have secured a certain amount or more of a specific element, and the phosphide obtained by reacting the specific element with phosphorus is used as a pinning particle. We have found that it is possible to suppress the grain growth of a metal structure by using it, and completed the present invention.
上記目的を達成し得た鋼材は、以下のとおりである。
（１）質量％で、
Ｃ：０．００１～１．０００％、
Ｓｉ：０．０１～３．００％、
Ｍｎ：０．１０～４．５０％、
Ｐ：０．０００５～０．３００％、
Ｓ：０．０３００％以下、
Ａｌ：０．００１～５．０００％、
Ｎ：０．２０００％以下、
Ｏ：０．０１００％以下、
Ｐｒ：０～０．８０００％、Ｓｍ：０～０．８０００％、Ｅｕ：０～０．８０００％、Ｇｄ：０～０．８０００％、Ｔｂ：０～０．８０００％、Ｄｙ：０～０．８０００％、Ｈｏ：０～０．８０００％、Ｅｒ：０～０．８０００％、Ｔｍ：０～０．８０００％、Ｙｂ：０～０．８０００％、Ｌｕ：０～０．８０００％、及びＳｃ：０～０．８０００％からなる群より選択される少なくとも１種のＸ元素、
Ｎｂ：０～３．０００％、
Ｔｉ：０～０．５００％、
Ｔａ：０～０．５００％、
Ｖ：０～１．００％、
Ｃｕ：０～３．００％、
Ｎｉ：０～６０．００％、
Ｃｒ：０～３０．００％、
Ｍｏ：０～５．００％、
Ｗ：０～２．００％、
Ｂ：０～０．０２００％、
Ｃｏ：０～３．００％、
Ｂｅ：０～０．０５０％、
Ａｇ：０～０．５００％、
Ｚｒ：０～０．５０００％、
Ｈｆ：０～０．５０００％、
Ｃａ：０～０．０５００％、
Ｍｇ：０～０．０５００％、
Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種：合計で０～０．５０００％、
Ｓｎ：０～０．３００％、
Ｓｂ：０～０．３００％、
Ｔｅ：０～０．１００％、
Ｓｅ：０～０．１００％、
Ａｓ：０～０．０５０％、
Ｂｉ：０～０．５００％、
Ｐｂ：０～０．５００％、並びに
残部：Ｆｅ及び不純物からなり、
下記式１を満たす化学組成を有し、
前記Ｘ元素を含有するリン化物を含み、抽出残渣法によって測定される前記リン化物に含まれるＰ量が鋼材に対して０．０００３原子％以上であり、かつＴＥＭレプリカ法によって測定される前記リン化物の平均粒径が１００ｎｍ未満である、鋼材。
０．４０［Ｐｒ］＋０．３７［Ｓｍ］＋０．３７［Ｅｕ］＋０．３６［Ｇｄ］＋０．３５［Ｔｂ］＋０．３４［Ｄｙ］＋０．３４［Ｈｏ］＋０．３３［Ｅｒ］＋０．３３［Ｔｍ］＋０．３２［Ｙｂ］＋０．３２［Ｌｕ］＋１．２４［Ｓｃ］－２．３３［Ｏ］－３．９９［Ｎ］－１．７４［Ｓ］ ≧ ０．０００３ ・・・式１
ここで、［Ｐｒ］、［Ｓｍ］、［Ｅｕ］、［Ｇｄ］、［Ｔｂ］、［Ｄｙ］、［Ｈｏ］、［Ｅｒ］、［Ｔｍ］、［Ｙｂ］、［Ｌｕ］、［Ｓｃ］、［Ｏ］、［Ｎ］、及び［Ｓ］は、各元素の含有量［質量％］であり、元素を含有しない場合は０である。
（２）前記化学組成が、質量％で、
Ｎｂ：０．００３～３．０００％、
Ｔｉ：０．００５～０．５００％、
Ｔａ：０．００１～０．５００％、
Ｖ：０．００１～１．００％、
Ｃｕ：０．００１～３．００％、
Ｎｉ：０．００１～６０．００％、
Ｃｒ：０．００１～３０．００％、
Ｍｏ：０．００１～５．００％、
Ｗ：０．００１～２．００％、
Ｂ：０．０００１～０．０２００％、
Ｃｏ：０．００１～３．００％、
Ｂｅ：０．０００３～０．０５０％、
Ａｇ：０．００１～０．５００％、
Ｚｒ：０．０００１～０．５０００％、
Ｈｆ：０．０００１～０．５０００％、
Ｃａ：０．０００１～０．０５００％、
Ｍｇ：０．０００１～０．０５００％、
Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種：合計で０．０００１～０．５０００％、
Ｓｎ：０．００１～０．３００％、
Ｓｂ：０．００１～０．３００％、
Ｔｅ：０．００１～０．１００％、
Ｓｅ：０．００１～０．１００％、
Ａｓ：０．００１～０．０５０％、
Ｂｉ：０．００１～０．５００％、並びに
Ｐｂ：０．００１～０．５００％
のうち１種又は２種以上を含む、上記（１）に記載の鋼材。 The steel materials that have achieved the above objectives are as follows.
(1) By mass%,
C: 0.001 to 1.000%,
Si: 0.01-3.00%,
Mn: 0.10 to 4.50%,
P: 0.0005 to 0.300%,
S: 0.0300% or less,
Al: 0.001-5.000%,
N: 0.2000% or less,
O: 0.0100% or less,
Pr: 0 to 0.8000%, Sm: 0 to 0.8000%, Eu: 0 to 0.8000%, Gd: 0 to 0.8000%, Tb: 0 to 0.8000%, Dy: 0 to 0 .8000%, Ho: 0 to 0.8000%, Er: 0 to 0.8000%, Tm: 0 to 0.8000%, Yb: 0 to 0.8000%, Lu: 0 to 0.8000%, and Sc: At least one X element selected from the group consisting of 0 to 0.8000%,
Nb: 0-3.000%,
Ti: 0 to 0.500%,
Ta: 0 to 0.500%,
V: 0 to 1.00%,
Cu: 0 to 3.00%,
Ni: 0-60.00%,
Cr: 0 to 30.00%,
Mo: 0 to 5.00%,
W: 0 to 2.00%,
B: 0-0.0200%,
Co: 0 to 3.00%,
Be: 0 to 0.050%,
Ag: 0 to 0.500%,
Zr: 0 to 0.5000%,
Hf: 0 to 0.5000%,
Ca: 0-0.0500%,
Mg: 0-0.0500%,
At least one of La, Ce, Nd, Pm and Y: 0 to 0.5000% in total,
Sn: 0 to 0.300%,
Sb: 0 to 0.300%,
Te: 0 to 0.100%,
Se: 0 to 0.100%,
As: 0 to 0.050%,
Bi: 0 to 0.500%,
Pb: 0 to 0.500%, and the balance: Fe and impurities.
It has a chemical composition that satisfies the followingformula 1 and has a chemical composition.
The phosphorus contained in the phosphide containing the X element, the amount of P contained in the phosphide measured by the extraction residue method is 0.0003 atomic% or more with respect to the steel material, and the phosphorus is measured by the TEM replica method. A steel material having an average particle size of a compound of less than 100 nm.
0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] +0. 33 [Tm] +0.32 [Yb] +0.32 [Lu] +1.24 [Sc] -2.33 [O] -3.99 [N] -1.74 [S] ≧ 0.0003 ...Equation 1
Here, [Pr], [Sm], [Eu], [Gd], [Tb], [Dy], [Ho], [Er], [Tm], [Yb], [Lu], [Sc]. , [O], [N], and [S] are the content [mass%] of each element, and are 0 when the element is not contained.
(2) The chemical composition is mass%.
Nb: 0.003 to 3.000%,
Ti: 0.005 to 0.500%,
Ta: 0.001 to 0.500%,
V: 0.001 to 1.00%,
Cu: 0.001 to 3.00%,
Ni: 0.001 to 60.00%,
Cr: 0.001 to 30.00%,
Mo: 0.001 to 5.00%,
W: 0.001 to 2.00%,
B: 0.0001-0.0200%,
Co: 0.001 to 3.00%,
Be: 0.0003 to 0.050%,
Ag: 0.001 to 0.500%,
Zr: 0.0001 to 0.5000%,
Hf: 0.0001 to 0.5000%,
Ca: 0.0001-0.0500%,
Mg: 0.0001-0.0500%,
At least one of La, Ce, Nd, Pm and Y: 0.0001 to 0.5000% in total,
Sn: 0.001 to 0.300%,
Sb: 0.001 to 0.300%,
Te: 0.001 to 0.100%,
Se: 0.001 to 0.100%,
As: 0.001 to 0.050%,
Bi: 0.001 to 0.500%, and Pb: 0.001 to 0.500%
The steel material according to (1) above, which comprises one or more of the above.
（１）質量％で、
Ｃ：０．００１～１．０００％、
Ｓｉ：０．０１～３．００％、
Ｍｎ：０．１０～４．５０％、
Ｐ：０．０００５～０．３００％、
Ｓ：０．０３００％以下、
Ａｌ：０．００１～５．０００％、
Ｎ：０．２０００％以下、
Ｏ：０．０１００％以下、
Ｐｒ：０～０．８０００％、Ｓｍ：０～０．８０００％、Ｅｕ：０～０．８０００％、Ｇｄ：０～０．８０００％、Ｔｂ：０～０．８０００％、Ｄｙ：０～０．８０００％、Ｈｏ：０～０．８０００％、Ｅｒ：０～０．８０００％、Ｔｍ：０～０．８０００％、Ｙｂ：０～０．８０００％、Ｌｕ：０～０．８０００％、及びＳｃ：０～０．８０００％からなる群より選択される少なくとも１種のＸ元素、
Ｎｂ：０～３．０００％、
Ｔｉ：０～０．５００％、
Ｔａ：０～０．５００％、
Ｖ：０～１．００％、
Ｃｕ：０～３．００％、
Ｎｉ：０～６０．００％、
Ｃｒ：０～３０．００％、
Ｍｏ：０～５．００％、
Ｗ：０～２．００％、
Ｂ：０～０．０２００％、
Ｃｏ：０～３．００％、
Ｂｅ：０～０．０５０％、
Ａｇ：０～０．５００％、
Ｚｒ：０～０．５０００％、
Ｈｆ：０～０．５０００％、
Ｃａ：０～０．０５００％、
Ｍｇ：０～０．０５００％、
Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種：合計で０～０．５０００％、
Ｓｎ：０～０．３００％、
Ｓｂ：０～０．３００％、
Ｔｅ：０～０．１００％、
Ｓｅ：０～０．１００％、
Ａｓ：０～０．０５０％、
Ｂｉ：０～０．５００％、
Ｐｂ：０～０．５００％、並びに
残部：Ｆｅ及び不純物からなり、
下記式１を満たす化学組成を有し、
前記Ｘ元素を含有するリン化物を含み、抽出残渣法によって測定される前記リン化物に含まれるＰ量が鋼材に対して０．０００３原子％以上であり、かつＴＥＭレプリカ法によって測定される前記リン化物の平均粒径が１００ｎｍ未満である、鋼材。
０．４０［Ｐｒ］＋０．３７［Ｓｍ］＋０．３７［Ｅｕ］＋０．３６［Ｇｄ］＋０．３５［Ｔｂ］＋０．３４［Ｄｙ］＋０．３４［Ｈｏ］＋０．３３［Ｅｒ］＋０．３３［Ｔｍ］＋０．３２［Ｙｂ］＋０．３２［Ｌｕ］＋１．２４［Ｓｃ］－２．３３［Ｏ］－３．９９［Ｎ］－１．７４［Ｓ］ ≧ ０．０００３ ・・・式１
ここで、［Ｐｒ］、［Ｓｍ］、［Ｅｕ］、［Ｇｄ］、［Ｔｂ］、［Ｄｙ］、［Ｈｏ］、［Ｅｒ］、［Ｔｍ］、［Ｙｂ］、［Ｌｕ］、［Ｓｃ］、［Ｏ］、［Ｎ］、及び［Ｓ］は、各元素の含有量［質量％］であり、元素を含有しない場合は０である。
（２）前記化学組成が、質量％で、
Ｎｂ：０．００３～３．０００％、
Ｔｉ：０．００５～０．５００％、
Ｔａ：０．００１～０．５００％、
Ｖ：０．００１～１．００％、
Ｃｕ：０．００１～３．００％、
Ｎｉ：０．００１～６０．００％、
Ｃｒ：０．００１～３０．００％、
Ｍｏ：０．００１～５．００％、
Ｗ：０．００１～２．００％、
Ｂ：０．０００１～０．０２００％、
Ｃｏ：０．００１～３．００％、
Ｂｅ：０．０００３～０．０５０％、
Ａｇ：０．００１～０．５００％、
Ｚｒ：０．０００１～０．５０００％、
Ｈｆ：０．０００１～０．５０００％、
Ｃａ：０．０００１～０．０５００％、
Ｍｇ：０．０００１～０．０５００％、
Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種：合計で０．０００１～０．５０００％、
Ｓｎ：０．００１～０．３００％、
Ｓｂ：０．００１～０．３００％、
Ｔｅ：０．００１～０．１００％、
Ｓｅ：０．００１～０．１００％、
Ａｓ：０．００１～０．０５０％、
Ｂｉ：０．００１～０．５００％、並びに
Ｐｂ：０．００１～０．５００％
のうち１種又は２種以上を含む、上記（１）に記載の鋼材。 The steel materials that have achieved the above objectives are as follows.
(1) By mass%,
C: 0.001 to 1.000%,
Si: 0.01-3.00%,
Mn: 0.10 to 4.50%,
P: 0.0005 to 0.300%,
S: 0.0300% or less,
Al: 0.001-5.000%,
N: 0.2000% or less,
O: 0.0100% or less,
Pr: 0 to 0.8000%, Sm: 0 to 0.8000%, Eu: 0 to 0.8000%, Gd: 0 to 0.8000%, Tb: 0 to 0.8000%, Dy: 0 to 0 .8000%, Ho: 0 to 0.8000%, Er: 0 to 0.8000%, Tm: 0 to 0.8000%, Yb: 0 to 0.8000%, Lu: 0 to 0.8000%, and Sc: At least one X element selected from the group consisting of 0 to 0.8000%,
Nb: 0-3.000%,
Ti: 0 to 0.500%,
Ta: 0 to 0.500%,
V: 0 to 1.00%,
Cu: 0 to 3.00%,
Ni: 0-60.00%,
Cr: 0 to 30.00%,
Mo: 0 to 5.00%,
W: 0 to 2.00%,
B: 0-0.0200%,
Co: 0 to 3.00%,
Be: 0 to 0.050%,
Ag: 0 to 0.500%,
Zr: 0 to 0.5000%,
Hf: 0 to 0.5000%,
Ca: 0-0.0500%,
Mg: 0-0.0500%,
At least one of La, Ce, Nd, Pm and Y: 0 to 0.5000% in total,
Sn: 0 to 0.300%,
Sb: 0 to 0.300%,
Te: 0 to 0.100%,
Se: 0 to 0.100%,
As: 0 to 0.050%,
Bi: 0 to 0.500%,
Pb: 0 to 0.500%, and the balance: Fe and impurities.
It has a chemical composition that satisfies the following
The phosphorus contained in the phosphide containing the X element, the amount of P contained in the phosphide measured by the extraction residue method is 0.0003 atomic% or more with respect to the steel material, and the phosphorus is measured by the TEM replica method. A steel material having an average particle size of a compound of less than 100 nm.
0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] +0. 33 [Tm] +0.32 [Yb] +0.32 [Lu] +1.24 [Sc] -2.33 [O] -3.99 [N] -1.74 [S] ≧ 0.0003 ...
Here, [Pr], [Sm], [Eu], [Gd], [Tb], [Dy], [Ho], [Er], [Tm], [Yb], [Lu], [Sc]. , [O], [N], and [S] are the content [mass%] of each element, and are 0 when the element is not contained.
(2) The chemical composition is mass%.
Nb: 0.003 to 3.000%,
Ti: 0.005 to 0.500%,
Ta: 0.001 to 0.500%,
V: 0.001 to 1.00%,
Cu: 0.001 to 3.00%,
Ni: 0.001 to 60.00%,
Cr: 0.001 to 30.00%,
Mo: 0.001 to 5.00%,
W: 0.001 to 2.00%,
B: 0.0001-0.0200%,
Co: 0.001 to 3.00%,
Be: 0.0003 to 0.050%,
Ag: 0.001 to 0.500%,
Zr: 0.0001 to 0.5000%,
Hf: 0.0001 to 0.5000%,
Ca: 0.0001-0.0500%,
Mg: 0.0001-0.0500%,
At least one of La, Ce, Nd, Pm and Y: 0.0001 to 0.5000% in total,
Sn: 0.001 to 0.300%,
Sb: 0.001 to 0.300%,
Te: 0.001 to 0.100%,
Se: 0.001 to 0.100%,
As: 0.001 to 0.050%,
Bi: 0.001 to 0.500%, and Pb: 0.001 to 0.500%
The steel material according to (1) above, which comprises one or more of the above.
本発明によれば、金属組織の粒成長を抑制可能な鋼材を提供することができる。
According to the present invention, it is possible to provide a steel material capable of suppressing grain growth of a metal structure.
＜鋼材＞
本発明の実施形態に係る鋼材は、質量％で、
Ｃ：０．００１～１．０００％、
Ｓｉ：０．０１～３．００％、
Ｍｎ：０．１０～４．５０％、
Ｐ：０．０００５～０．３００％、
Ｓ：０．０３００％以下、
Ａｌ：０．００１～５．０００％、
Ｎ：０．２０００％以下、
Ｏ：０．０１００％以下、
Ｐｒ：０～０．８０００％、Ｓｍ：０～０．８０００％、Ｅｕ：０～０．８０００％、Ｇｄ：０～０．８０００％、Ｔｂ：０～０．８０００％、Ｄｙ：０～０．８０００％、Ｈｏ：０～０．８０００％、Ｅｒ：０～０．８０００％、Ｔｍ：０～０．８０００％、Ｙｂ：０～０．８０００％、Ｌｕ：０～０．８０００％、及びＳｃ：０～０．８０００％からなる群より選択される少なくとも１種のＸ元素、
Ｎｂ：０～３．０００％、
Ｔｉ：０～０．５００％、
Ｔａ：０～０．５００％、
Ｖ：０～１．００％、
Ｃｕ：０～３．００％、
Ｎｉ：０～６０．００％、
Ｃｒ：０～３０．００％、
Ｍｏ：０～５．００％、
Ｗ：０～２．００％、
Ｂ：０～０．０２００％、
Ｃｏ：０～３．００％、
Ｂｅ：０～０．０５０％、
Ａｇ：０～０．５００％、
Ｚｒ：０～０．５０００％、
Ｈｆ：０～０．５０００％、
Ｃａ：０～０．０５００％、
Ｍｇ：０～０．０５００％、
Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種：合計で０～０．５０００％、
Ｓｎ：０～０．３００％、
Ｓｂ：０～０．３００％、
Ｔｅ：０～０．１００％、
Ｓｅ：０～０．１００％、
Ａｓ：０～０．０５０％、
Ｂｉ：０～０．５００％、
Ｐｂ：０～０．５００％、並びに
残部：Ｆｅ及び不純物からなり、
下記式１を満たす化学組成を有し、
前記Ｘ元素を含有するリン化物を含み、抽出残渣法によって測定される前記リン化物に含まれるＰ量が鋼材に対して０．０００３原子％以上であり、かつＴＥＭレプリカ法によって測定される前記リン化物の平均粒径が１００ｎｍ未満であることを特徴としている。
０．４０［Ｐｒ］＋０．３７［Ｓｍ］＋０．３７［Ｅｕ］＋０．３６［Ｇｄ］＋０．３５［Ｔｂ］＋０．３４［Ｄｙ］＋０．３４［Ｈｏ］＋０．３３［Ｅｒ］＋０．３３［Ｔｍ］＋０．３２［Ｙｂ］＋０．３２［Ｌｕ］＋１．２４［Ｓｃ］－２．３３［Ｏ］－３．９９［Ｎ］－１．７４［Ｓ］ ≧ ０．０００３ ・・・式１
ここで、［Ｐｒ］、［Ｓｍ］、［Ｅｕ］、［Ｇｄ］、［Ｔｂ］、［Ｄｙ］、［Ｈｏ］、［Ｅｒ］、［Ｔｍ］、［Ｙｂ］、［Ｌｕ］、［Ｓｃ］、［Ｏ］、［Ｎ］、及び［Ｓ］は、各元素の含有量［質量％］であり、元素を含有しない場合は０である。 <Steel material>
The steel material according to the embodiment of the present invention is based on mass%.
C: 0.001 to 1.000%,
Si: 0.01-3.00%,
Mn: 0.10 to 4.50%,
P: 0.0005 to 0.300%,
S: 0.0300% or less,
Al: 0.001-5.000%,
N: 0.2000% or less,
O: 0.0100% or less,
Pr: 0 to 0.8000%, Sm: 0 to 0.8000%, Eu: 0 to 0.8000%, Gd: 0 to 0.8000%, Tb: 0 to 0.8000%, Dy: 0 to 0 .8000%, Ho: 0 to 0.8000%, Er: 0 to 0.8000%, Tm: 0 to 0.8000%, Yb: 0 to 0.8000%, Lu: 0 to 0.8000%, and Sc: At least one X element selected from the group consisting of 0 to 0.8000%,
Nb: 0-3.000%,
Ti: 0 to 0.500%,
Ta: 0 to 0.500%,
V: 0 to 1.00%,
Cu: 0 to 3.00%,
Ni: 0-60.00%,
Cr: 0 to 30.00%,
Mo: 0 to 5.00%,
W: 0 to 2.00%,
B: 0-0.0200%,
Co: 0 to 3.00%,
Be: 0 to 0.050%,
Ag: 0 to 0.500%,
Zr: 0 to 0.5000%,
Hf: 0 to 0.5000%,
Ca: 0-0.0500%,
Mg: 0-0.0500%,
At least one of La, Ce, Nd, Pm and Y: 0 to 0.5000% in total,
Sn: 0 to 0.300%,
Sb: 0 to 0.300%,
Te: 0 to 0.100%,
Se: 0 to 0.100%,
As: 0 to 0.050%,
Bi: 0 to 0.500%,
Pb: 0 to 0.500%, and the balance: Fe and impurities.
It has a chemical composition that satisfies the followingformula 1 and has a chemical composition.
The phosphorus contained in the phosphide containing the X element, the amount of P contained in the phosphide measured by the extraction residue method is 0.0003 atomic% or more with respect to the steel material, and the phosphorus is measured by the TEM replica method. It is characterized in that the average particle size of the compound is less than 100 nm.
0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] +0. 33 [Tm] +0.32 [Yb] +0.32 [Lu] +1.24 [Sc] -2.33 [O] -3.99 [N] -1.74 [S] ≧ 0.0003 ...Equation 1
Here, [Pr], [Sm], [Eu], [Gd], [Tb], [Dy], [Ho], [Er], [Tm], [Yb], [Lu], [Sc]. , [O], [N], and [S] are the content [mass%] of each element, and are 0 when the element is not contained.
本発明の実施形態に係る鋼材は、質量％で、
Ｃ：０．００１～１．０００％、
Ｓｉ：０．０１～３．００％、
Ｍｎ：０．１０～４．５０％、
Ｐ：０．０００５～０．３００％、
Ｓ：０．０３００％以下、
Ａｌ：０．００１～５．０００％、
Ｎ：０．２０００％以下、
Ｏ：０．０１００％以下、
Ｐｒ：０～０．８０００％、Ｓｍ：０～０．８０００％、Ｅｕ：０～０．８０００％、Ｇｄ：０～０．８０００％、Ｔｂ：０～０．８０００％、Ｄｙ：０～０．８０００％、Ｈｏ：０～０．８０００％、Ｅｒ：０～０．８０００％、Ｔｍ：０～０．８０００％、Ｙｂ：０～０．８０００％、Ｌｕ：０～０．８０００％、及びＳｃ：０～０．８０００％からなる群より選択される少なくとも１種のＸ元素、
Ｎｂ：０～３．０００％、
Ｔｉ：０～０．５００％、
Ｔａ：０～０．５００％、
Ｖ：０～１．００％、
Ｃｕ：０～３．００％、
Ｎｉ：０～６０．００％、
Ｃｒ：０～３０．００％、
Ｍｏ：０～５．００％、
Ｗ：０～２．００％、
Ｂ：０～０．０２００％、
Ｃｏ：０～３．００％、
Ｂｅ：０～０．０５０％、
Ａｇ：０～０．５００％、
Ｚｒ：０～０．５０００％、
Ｈｆ：０～０．５０００％、
Ｃａ：０～０．０５００％、
Ｍｇ：０～０．０５００％、
Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種：合計で０～０．５０００％、
Ｓｎ：０～０．３００％、
Ｓｂ：０～０．３００％、
Ｔｅ：０～０．１００％、
Ｓｅ：０～０．１００％、
Ａｓ：０～０．０５０％、
Ｂｉ：０～０．５００％、
Ｐｂ：０～０．５００％、並びに
残部：Ｆｅ及び不純物からなり、
下記式１を満たす化学組成を有し、
前記Ｘ元素を含有するリン化物を含み、抽出残渣法によって測定される前記リン化物に含まれるＰ量が鋼材に対して０．０００３原子％以上であり、かつＴＥＭレプリカ法によって測定される前記リン化物の平均粒径が１００ｎｍ未満であることを特徴としている。
０．４０［Ｐｒ］＋０．３７［Ｓｍ］＋０．３７［Ｅｕ］＋０．３６［Ｇｄ］＋０．３５［Ｔｂ］＋０．３４［Ｄｙ］＋０．３４［Ｈｏ］＋０．３３［Ｅｒ］＋０．３３［Ｔｍ］＋０．３２［Ｙｂ］＋０．３２［Ｌｕ］＋１．２４［Ｓｃ］－２．３３［Ｏ］－３．９９［Ｎ］－１．７４［Ｓ］ ≧ ０．０００３ ・・・式１
ここで、［Ｐｒ］、［Ｓｍ］、［Ｅｕ］、［Ｇｄ］、［Ｔｂ］、［Ｄｙ］、［Ｈｏ］、［Ｅｒ］、［Ｔｍ］、［Ｙｂ］、［Ｌｕ］、［Ｓｃ］、［Ｏ］、［Ｎ］、及び［Ｓ］は、各元素の含有量［質量％］であり、元素を含有しない場合は０である。 <Steel material>
The steel material according to the embodiment of the present invention is based on mass%.
C: 0.001 to 1.000%,
Si: 0.01-3.00%,
Mn: 0.10 to 4.50%,
P: 0.0005 to 0.300%,
S: 0.0300% or less,
Al: 0.001-5.000%,
N: 0.2000% or less,
O: 0.0100% or less,
Pr: 0 to 0.8000%, Sm: 0 to 0.8000%, Eu: 0 to 0.8000%, Gd: 0 to 0.8000%, Tb: 0 to 0.8000%, Dy: 0 to 0 .8000%, Ho: 0 to 0.8000%, Er: 0 to 0.8000%, Tm: 0 to 0.8000%, Yb: 0 to 0.8000%, Lu: 0 to 0.8000%, and Sc: At least one X element selected from the group consisting of 0 to 0.8000%,
Nb: 0-3.000%,
Ti: 0 to 0.500%,
Ta: 0 to 0.500%,
V: 0 to 1.00%,
Cu: 0 to 3.00%,
Ni: 0-60.00%,
Cr: 0 to 30.00%,
Mo: 0 to 5.00%,
W: 0 to 2.00%,
B: 0-0.0200%,
Co: 0 to 3.00%,
Be: 0 to 0.050%,
Ag: 0 to 0.500%,
Zr: 0 to 0.5000%,
Hf: 0 to 0.5000%,
Ca: 0-0.0500%,
Mg: 0-0.0500%,
At least one of La, Ce, Nd, Pm and Y: 0 to 0.5000% in total,
Sn: 0 to 0.300%,
Sb: 0 to 0.300%,
Te: 0 to 0.100%,
Se: 0 to 0.100%,
As: 0 to 0.050%,
Bi: 0 to 0.500%,
Pb: 0 to 0.500%, and the balance: Fe and impurities.
It has a chemical composition that satisfies the following
The phosphorus contained in the phosphide containing the X element, the amount of P contained in the phosphide measured by the extraction residue method is 0.0003 atomic% or more with respect to the steel material, and the phosphorus is measured by the TEM replica method. It is characterized in that the average particle size of the compound is less than 100 nm.
0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] +0. 33 [Tm] +0.32 [Yb] +0.32 [Lu] +1.24 [Sc] -2.33 [O] -3.99 [N] -1.74 [S] ≧ 0.0003 ...
Here, [Pr], [Sm], [Eu], [Gd], [Tb], [Dy], [Ho], [Er], [Tm], [Yb], [Lu], [Sc]. , [O], [N], and [S] are the content [mass%] of each element, and are 0 when the element is not contained.
鋼材に求められる材料特性、例えば低温靭性を向上させ及び／又は高強度と低温靭性の両立を図るためには、金属組織を微細化することが一般に重要である。従来、金属組織を微細化するために、例えば、鋼材を熱間圧延、より具体的には仕上げ圧延する際の終了温度を低温に制御することでオーステナイト結晶粒の再結晶を抑制し、このような再結晶の抑制に起因してフェライト変態の駆動力を高めてより多くの新しい結晶を生成させることが行われている。しかしながら、このような金属組織の微細化では、一般的に圧延によって特定の方向に集合組織が発達する傾向があるため、高い異方性を示す金属組織が得られることになる。したがって、等方的な金属組織であることが求められる用途、例えば、自動車の足廻り部品等の高い穴広げ性が要求される用途に適用するには適切でない場合がある。
It is generally important to miniaturize the metallographic structure in order to improve the material properties required for steel materials, for example, low temperature toughness and / or to achieve both high strength and low temperature toughness. Conventionally, in order to make the metal structure finer, for example, the recrystallization of austenite crystal grains is suppressed by controlling the end temperature at the time of hot rolling, more specifically, finish rolling of the steel material to a low temperature. Due to the suppression of recrystallization, the driving force of ferrite transformation is increased to generate more new crystals. However, in such miniaturization of the metal structure, generally, the texture tends to develop in a specific direction by rolling, so that a metal structure showing high anisotropy can be obtained. Therefore, it may not be suitable for applications that require an isotropic metal structure, for example, applications that require high hole expandability such as undercarriage parts of automobiles.
一方で、熱間圧延過程において再結晶域圧延、例えば粗圧延を活用することで、鋼材の金属組織を再結晶により微細化することも従来行われている。再結晶とは、熱間圧延等により塑性加工を与えた後、高温で保持したときに当該塑性加工によって蓄積された歪みエネルギーが原子位置の再配列を伴う拡散により解放され、新しい結晶粒が生成する現象である。このため、再結晶により微細化された金属組織は、一般的に異方性が少なく等方的な組織となる。したがって、等方的な金属組織が好まれる用途においては、再結晶による微細化は非常に有利である。しかしながら、再結晶による微細化の場合、鋼材中に蓄積された歪みエネルギーが再結晶によって消費された後、再結晶粒間の粒界エネルギーを駆動力として粒成長が起こる。このような現象は、再結晶域圧延後の温度が高い状態で特に顕著であるため、再結晶による微細化の場合であっても、微細な金属組織を安定的に維持することは一般に困難である。
On the other hand, it has been conventionally practiced to miniaturize the metal structure of a steel material by recrystallization by utilizing recrystallization region rolling, for example, rough rolling in the hot rolling process. Recrystallization means that after plastic working by hot rolling or the like, the strain energy accumulated by the plastic working when held at a high temperature is released by diffusion accompanied by rearrangement of atomic positions, and new crystal grains are generated. It is a phenomenon that occurs. Therefore, the metal structure refined by recrystallization generally has less anisotropy and becomes an isotropic structure. Therefore, in applications where an isotropic metallographic structure is preferred, miniaturization by recrystallization is very advantageous. However, in the case of miniaturization by recrystallization, after the strain energy accumulated in the steel material is consumed by the recrystallization, grain growth occurs by using the grain boundary energy between the recrystallized grains as a driving force. Since such a phenomenon is particularly remarkable when the temperature after rolling in the recrystallization region is high, it is generally difficult to stably maintain a fine metal structure even in the case of miniaturization by recrystallization. be.
これに関連して、粗大な組織の形成を抑制するためにピン止め粒子の利用及び制御が有効な場合があることが知られている。このような観点から、本発明者らは、金属組織の粒成長を抑制するためのピン止め粒子として利用し得る鋼中の元素について検討を行った。その結果、本発明者らは、Ｐｒ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ、及びＳｃの元素（以下、「Ｘ元素」ともいう）の量をそれらの元素が鋼中で形成する介在物、より具体的にはこれらの元素の酸化物、窒化物及び硫化物との関係を考慮しつつ一定量以上確保し（すなわち、式１の左辺に対応する当該Ｘ元素の有効量を０．０００３％以上とし）、さらに当該特定元素を鋼中のＰと反応させて、比較的多くかつ微細なリン化物を形成することにより（すなわち、抽出残渣法によって測定されるリン化物中のＰ量が鋼材に対して０．０００３原子％以上であり、かつＴＥＭレプリカ法によって測定される平均粒径が１００ｎｍ未満であるリン化物を形成することにより）、当該リン化物をピン止め粒子として有効に機能させることができ、その結果として金属組織の粒成長を顕著に抑制することができることを見出した。
In this regard, it is known that the use and control of pinned particles may be effective in suppressing the formation of coarse tissue. From this point of view, the present inventors have studied elements in steel that can be used as pinning particles for suppressing grain growth of a metal structure. As a result, the present inventors refer to the amounts of the elements of Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc (hereinafter, also referred to as "X element") thereof. A certain amount or more is secured while considering the relationship between the inclusions formed by the elements in the steel, more specifically, the oxides, nitrides and sulfides of these elements (that is, the said corresponding to the left side of the formula 1). The effective amount of the element X is 0.0003% or more), and the specific element is reacted with P in the steel to form a relatively large and fine phosphate (that is, measured by the extraction residue method). The amount of P in the phosphonic acid is 0.0003 atomic% or more with respect to the steel material, and the average particle size measured by the TEM replica method is less than 100 nm). It has been found that the particles can be effectively functioned as pinning particles, and as a result, the grain growth of the metal structure can be remarkably suppressed.
上記のＸ元素は、鋼中に存在するＯ（酸素）、Ｎ（窒素）及びＳ（硫黄）と結びついて、酸化物、窒化物及び硫化物からなる介在物を形成しやすいという性質を有する。Ｘ元素が鋼中でこのような介在物を形成してしまうと、鋼中のＰとの反応に寄与することができるＸ元素の量が少なくなり、ピン止め粒子としてのリン化物を十分に形成することができなくなる。本発明においては、このような介在物を考慮したＸ元素の量を、後で詳しく説明する上記式１によって当該Ｘ元素の有効量として算出しそして当該有効量を一定量以上、すなわち０．０００３％以上確保することで、当該Ｘ元素を鋼中のＰと反応させ、ピン止め粒子として有効に機能させるのに十分な量のリン化物を形成することができる。本発明者らの検討の結果、このようなリン化物の量及びサイズを、同様に後で詳しく説明するように、抽出残渣法によって測定されるリン化物中のＰ量が鋼材に対して０．０００３原子％以上でかつＴＥＭレプリカ法によって測定される平均粒径が１００ｎｍ未満の範囲内とすることで、より高いピン止め効果を達成できることが見出された。本発明によれば、このようなピン止め効果は、金属組織の微細化が再結晶によるものか否かにかかわらず有効に作用することができる。例えば、金属組織の微細化が再結晶によるものである場合には、具体的には、まず熱間圧延の際に再結晶したオーステナイト中に存在しているＸ元素がＰと反応して微細なリン化物が析出し、当該リン化物のピン止め効果により再結晶オーステナイト粒の成長が抑制される。金属組織がオーステナイトである鋼材は、結晶粒が微細になり、金属組織がマルテンサイトである鋼材は、いわゆる旧オーステナイト粒が微細になる。次いで熱間圧延終了後、温度が下がる過程で微細な再結晶オーステナイト粒が微細なフェライト組織へと変態する場合には、等方的でかつ微細なフェライト組織を含む金属組織を安定的に維持することが可能となる。一方、金属組織の微細化が再結晶によるものでない場合、例えばオーステナイトの再結晶を伴わない熱間圧延終了後の再加熱時においてもリン化物のピン止め効果によりオーステナイト粒の成長は抑制される。
The above element X has the property of easily forming inclusions composed of oxides, nitrides and sulfides in combination with O (oxygen), N (nitrogen) and S (sulfur) existing in steel. When the X element forms such inclusions in the steel, the amount of the X element that can contribute to the reaction with P in the steel decreases, and a phosphide as a pinning particle is sufficiently formed. You will not be able to. In the present invention, the amount of the X element in consideration of such inclusions is calculated as the effective amount of the X element by the above formula 1 which will be described in detail later, and the effective amount is a certain amount or more, that is, 0.0003. By securing% or more, the element X can be reacted with P in the steel to form a sufficient amount of phospholides to effectively function as pinning particles. As a result of the studies by the present inventors, the amount and size of such a phosphide are as described in detail later, and the amount of P in the phosphide measured by the extraction residue method is 0. It has been found that a higher pinning effect can be achieved by keeping the average particle size in the range of 0003 atomic% or more and the average particle size measured by the TEM replica method within the range of less than 100 nm. According to the present invention, such a pinning effect can be effectively applied regardless of whether or not the miniaturization of the metal structure is due to recrystallization. For example, when the micronization of the metal structure is due to recrystallization, specifically, the X element present in the recrystallized austenite during hot rolling reacts with P to become fine. The phosphite is precipitated, and the pinning effect of the phosphite suppresses the growth of recrystallized austenite grains. A steel material having an austenite metal structure has fine crystal grains, and a steel material having a martensite metal structure has fine so-called old austenite grains. Next, when the fine recrystallized austenite grains transform into a fine ferrite structure in the process of lowering the temperature after the completion of hot rolling, the metal structure containing an isotropic and fine ferrite structure is stably maintained. It becomes possible. On the other hand, when the miniaturization of the metal structure is not due to recrystallization, for example, the growth of austenite grains is suppressed by the pinning effect of the phosphide even at the time of reheating after the completion of hot rolling without recrystallization of austenite.
本発明におけるＸ元素は、上記のとおりＯ、Ｎ及びＳと結びついて介在物を形成しやすく、それゆえ鋼中で所定の有効量を確保することは一般に困難である。このような事情から、上記Ｘ元素を含有するリン化物によるピン止め効果は従来知られていなかった。しかしながら、近年の精錬技術の進歩により、一般に不純物として鋼中に存在するＯ、Ｎ及びＳなどの元素の含有量を非常に低いレベルにまで低減することが可能となったこともあり、今回、上記Ｘ元素の所定範囲内における有効量を実現することができた。したがって、上記Ｘ元素を含有するリン化物のピン止め効果は、今回、本発明者らによって初めて明らかにされたことであり、極めて意外であり、また驚くべきことである。
The element X in the present invention easily combines with O, N and S to form inclusions as described above, and therefore it is generally difficult to secure a predetermined effective amount in steel. Under these circumstances, the pinning effect of the phosphide containing the X element has not been known so far. However, recent advances in refining technology have made it possible to reduce the content of elements such as O, N, and S, which are generally present in steel as impurities, to extremely low levels. It was possible to realize an effective amount of the X element within a predetermined range. Therefore, the pinning effect of the phosphide containing the X element was first clarified by the present inventors, and is extremely surprising and surprising.
以下、本発明の実施形態に係る鋼材についてより詳しく説明する。以下の説明において、各元素の含有量の単位である「％」は、特に断りがない限り「質量％」を意味するものである。また、本明細書において、数値範囲を示す「～」とは、特に断りがない場合、その前後に記載される数値を下限値及び上限値として含む意味で使用される。
Hereinafter, the steel material according to the embodiment of the present invention will be described in more detail. In the following description, "%", which is a unit of the content of each element, means "mass%" unless otherwise specified. Further, in the present specification, "-" indicating a numerical range is used to mean that the numerical values described before and after the numerical range are included as the lower limit value and the upper limit value unless otherwise specified.
［Ｃ：０．００１～１．０００％］
炭素（Ｃ）は、硬さの安定化及び／又は強度の確保に必要な元素である。これらの効果を十分に得るために、Ｃ含有量は０．００１％以上である。Ｃ含有量は０．００５％以上、０．０１０％以上又は０．０２０％以上であってもよい。一方で、Ｃを過度に含有すると、靭性、曲げ性及び／又は溶接性が低下する場合がある。したがって、Ｃ含有量は１．０００％以下である。Ｃ含有量は０．８００％以下、０．６００％以下又は０．５００％以下であってもよい。 [C: 0.001 to 1.000%]
Carbon (C) is an element necessary for stabilizing hardness and / or ensuring strength. In order to sufficiently obtain these effects, the C content is 0.001% or more. The C content may be 0.005% or more, 0.010% or more, or 0.020% or more. On the other hand, if C is excessively contained, toughness, bendability and / or weldability may decrease. Therefore, the C content is 1.000% or less. The C content may be 0.800% or less, 0.600% or less, or 0.500% or less.
炭素（Ｃ）は、硬さの安定化及び／又は強度の確保に必要な元素である。これらの効果を十分に得るために、Ｃ含有量は０．００１％以上である。Ｃ含有量は０．００５％以上、０．０１０％以上又は０．０２０％以上であってもよい。一方で、Ｃを過度に含有すると、靭性、曲げ性及び／又は溶接性が低下する場合がある。したがって、Ｃ含有量は１．０００％以下である。Ｃ含有量は０．８００％以下、０．６００％以下又は０．５００％以下であってもよい。 [C: 0.001 to 1.000%]
Carbon (C) is an element necessary for stabilizing hardness and / or ensuring strength. In order to sufficiently obtain these effects, the C content is 0.001% or more. The C content may be 0.005% or more, 0.010% or more, or 0.020% or more. On the other hand, if C is excessively contained, toughness, bendability and / or weldability may decrease. Therefore, the C content is 1.000% or less. The C content may be 0.800% or less, 0.600% or less, or 0.500% or less.
［Ｓｉ：０．０１～３．００％］
ケイ素（Ｓｉ）は脱酸元素であり、強度の向上にも寄与する元素である。これらの効果を十分に得るために、Ｓｉ含有量は０．０１％以上である。Ｓｉ含有量は０．０５％以上、０．１０％以上又は０．３０％以上であってもよい。一方で、Ｓｉを過度に含有すると、靭性が低下したり、スケール疵と呼ばれる表面品質不良を発生したりする場合がある。したがって、Ｓｉ含有量は３．００％以下である。Ｓｉ含有量は２．００％以下、１．００％以下又は０．６０％以下であってもよい。 [Si: 0.01 to 3.00%]
Silicon (Si) is a deoxidizing element and is an element that also contributes to the improvement of strength. In order to sufficiently obtain these effects, the Si content is 0.01% or more. The Si content may be 0.05% or more, 0.10% or more, or 0.30% or more. On the other hand, if Si is excessively contained, the toughness may be lowered or surface quality defects called scale defects may occur. Therefore, the Si content is 3.00% or less. The Si content may be 2.00% or less, 1.00% or less, or 0.60% or less.
ケイ素（Ｓｉ）は脱酸元素であり、強度の向上にも寄与する元素である。これらの効果を十分に得るために、Ｓｉ含有量は０．０１％以上である。Ｓｉ含有量は０．０５％以上、０．１０％以上又は０．３０％以上であってもよい。一方で、Ｓｉを過度に含有すると、靭性が低下したり、スケール疵と呼ばれる表面品質不良を発生したりする場合がある。したがって、Ｓｉ含有量は３．００％以下である。Ｓｉ含有量は２．００％以下、１．００％以下又は０．６０％以下であってもよい。 [Si: 0.01 to 3.00%]
Silicon (Si) is a deoxidizing element and is an element that also contributes to the improvement of strength. In order to sufficiently obtain these effects, the Si content is 0.01% or more. The Si content may be 0.05% or more, 0.10% or more, or 0.30% or more. On the other hand, if Si is excessively contained, the toughness may be lowered or surface quality defects called scale defects may occur. Therefore, the Si content is 3.00% or less. The Si content may be 2.00% or less, 1.00% or less, or 0.60% or less.
［Ｍｎ：０．１０～４．５０％］
マンガン（Ｍｎ）は、焼入れ性及び／又は強度の向上に有効な元素であり、有効なオーステナイト安定化元素でもある。これらの効果を十分に得るために、Ｍｎ含有量は０．１０％以上である。Ｍｎ含有量は０．５０％以上、０．７０％以上又は１．００％以上であってもよい。一方で、Ｍｎを過度に含有すると、靭性に有害なＭｎＳが生成したり、耐酸化性を低下させたりする場合がある。したがって、Ｍｎ含有量は４．５０％以下である。Ｍｎ含有量は４．００％以下、３．５０％以下又は３．００％以下であってもよい。 [Mn: 0.10 to 4.50%]
Manganese (Mn) is an element effective for improving hardenability and / or strength, and is also an effective austenite stabilizing element. In order to sufficiently obtain these effects, the Mn content is 0.10% or more. The Mn content may be 0.50% or more, 0.70% or more, or 1.00% or more. On the other hand, if Mn is excessively contained, MnS harmful to toughness may be generated or the oxidation resistance may be lowered. Therefore, the Mn content is 4.50% or less. The Mn content may be 4.00% or less, 3.50% or less, or 3.00% or less.
マンガン（Ｍｎ）は、焼入れ性及び／又は強度の向上に有効な元素であり、有効なオーステナイト安定化元素でもある。これらの効果を十分に得るために、Ｍｎ含有量は０．１０％以上である。Ｍｎ含有量は０．５０％以上、０．７０％以上又は１．００％以上であってもよい。一方で、Ｍｎを過度に含有すると、靭性に有害なＭｎＳが生成したり、耐酸化性を低下させたりする場合がある。したがって、Ｍｎ含有量は４．５０％以下である。Ｍｎ含有量は４．００％以下、３．５０％以下又は３．００％以下であってもよい。 [Mn: 0.10 to 4.50%]
Manganese (Mn) is an element effective for improving hardenability and / or strength, and is also an effective austenite stabilizing element. In order to sufficiently obtain these effects, the Mn content is 0.10% or more. The Mn content may be 0.50% or more, 0.70% or more, or 1.00% or more. On the other hand, if Mn is excessively contained, MnS harmful to toughness may be generated or the oxidation resistance may be lowered. Therefore, the Mn content is 4.50% or less. The Mn content may be 4.00% or less, 3.50% or less, or 3.00% or less.
［Ｐ：０．０００５～０．３００％］
リン（Ｐ）は一般的に製造工程で混入する元素であるが、本発明の実施形態においてはピン止め粒子であるリン化物を構成する元素として粒成長の抑制に有効に機能する。このような効果を十分に得るために、Ｐ含有量は０．０００５％以上である。Ｐ含有量は０．００１％以上、０．００２％以上、０．００３％以上、０．００５％以上、又は、０．００７％以上であってもよい。一方で、Ｐを過度に含有すると、鋼材の加工性及び／又は靭性が低下する場合がある。したがって、Ｐ含有量は０．３００％以下である。Ｐ含有量は０．１００％以下、０．０５０％以下又は０．０３０％以下であってもよい。 [P: 0.0005 to 0.300%]
Phosphorus (P) is an element that is generally mixed in the manufacturing process, but in the embodiment of the present invention, it effectively functions as an element constituting a phosphide, which is a pinning particle, in suppressing grain growth. In order to sufficiently obtain such an effect, the P content is 0.0005% or more. The P content may be 0.001% or more, 0.002% or more, 0.003% or more, 0.005% or more, or 0.007% or more. On the other hand, if P is excessively contained, the workability and / or toughness of the steel material may decrease. Therefore, the P content is 0.300% or less. The P content may be 0.100% or less, 0.050% or less, or 0.030% or less.
リン（Ｐ）は一般的に製造工程で混入する元素であるが、本発明の実施形態においてはピン止め粒子であるリン化物を構成する元素として粒成長の抑制に有効に機能する。このような効果を十分に得るために、Ｐ含有量は０．０００５％以上である。Ｐ含有量は０．００１％以上、０．００２％以上、０．００３％以上、０．００５％以上、又は、０．００７％以上であってもよい。一方で、Ｐを過度に含有すると、鋼材の加工性及び／又は靭性が低下する場合がある。したがって、Ｐ含有量は０．３００％以下である。Ｐ含有量は０．１００％以下、０．０５０％以下又は０．０３０％以下であってもよい。 [P: 0.0005 to 0.300%]
Phosphorus (P) is an element that is generally mixed in the manufacturing process, but in the embodiment of the present invention, it effectively functions as an element constituting a phosphide, which is a pinning particle, in suppressing grain growth. In order to sufficiently obtain such an effect, the P content is 0.0005% or more. The P content may be 0.001% or more, 0.002% or more, 0.003% or more, 0.005% or more, or 0.007% or more. On the other hand, if P is excessively contained, the workability and / or toughness of the steel material may decrease. Therefore, the P content is 0.300% or less. The P content may be 0.100% or less, 0.050% or less, or 0.030% or less.
［Ｓ：０．０３００％以下］
硫黄（Ｓ）は製造工程で混入する元素であり、本発明の実施形態に係るＸ元素との間で形成される介在物を低減する観点からは少ないほど好ましく、よってＳ含有量は０％であってもよい。しかしながら、Ｓ含有量を０．０００１％未満に低減するためには精錬に時間を要し、生産性の低下を招く。したがって、Ｓ含有量は０．０００１％以上、０．０００５％以上又は０．００１０％以上であってもよい。一方で、Ｓを過度に含有すると、Ｘ元素の有効量が低下するとともに、靭性が低下する場合がある。したがって、Ｓ含有量は０．０３００％以下である。Ｓ含有量は好ましくは０．０１００％以下、より好ましくは０．００５０％以下、最も好ましくは０．００３０％以下である。 [S: 0.0300% or less]
Sulfur (S) is an element mixed in the manufacturing process, and is preferable from the viewpoint of reducing inclusions formed with the X element according to the embodiment of the present invention, so that the S content is 0%. There may be. However, in order to reduce the S content to less than 0.0001%, it takes time for refining, which leads to a decrease in productivity. Therefore, the S content may be 0.0001% or more, 0.0005% or more, or 0.0010% or more. On the other hand, if S is excessively contained, the effective amount of the X element may decrease and the toughness may decrease. Therefore, the S content is 0.0300% or less. The S content is preferably 0.0100% or less, more preferably 0.0050% or less, and most preferably 0.0030% or less.
硫黄（Ｓ）は製造工程で混入する元素であり、本発明の実施形態に係るＸ元素との間で形成される介在物を低減する観点からは少ないほど好ましく、よってＳ含有量は０％であってもよい。しかしながら、Ｓ含有量を０．０００１％未満に低減するためには精錬に時間を要し、生産性の低下を招く。したがって、Ｓ含有量は０．０００１％以上、０．０００５％以上又は０．００１０％以上であってもよい。一方で、Ｓを過度に含有すると、Ｘ元素の有効量が低下するとともに、靭性が低下する場合がある。したがって、Ｓ含有量は０．０３００％以下である。Ｓ含有量は好ましくは０．０１００％以下、より好ましくは０．００５０％以下、最も好ましくは０．００３０％以下である。 [S: 0.0300% or less]
Sulfur (S) is an element mixed in the manufacturing process, and is preferable from the viewpoint of reducing inclusions formed with the X element according to the embodiment of the present invention, so that the S content is 0%. There may be. However, in order to reduce the S content to less than 0.0001%, it takes time for refining, which leads to a decrease in productivity. Therefore, the S content may be 0.0001% or more, 0.0005% or more, or 0.0010% or more. On the other hand, if S is excessively contained, the effective amount of the X element may decrease and the toughness may decrease. Therefore, the S content is 0.0300% or less. The S content is preferably 0.0100% or less, more preferably 0.0050% or less, and most preferably 0.0030% or less.
［Ａｌ：０．００１～５．０００％］
アルミニウム（Ａｌ）は、脱酸元素であり、耐食性及び／又は耐熱性を向上させるのに有効な元素でもある。これらの効果を得るために、Ａｌ含有量は０．００１％以上である。Ａｌ含有量は０．０１０％以上、０．１００％以上又は０．２００％以上であってもよい。とりわけ、耐熱性を十分に向上させる観点からは、Ａｌ含有量は１．０００％以上、２．０００％以上又は３．０００％以上であってもよい。一方で、Ａｌを過度に含有すると、粗大な介在物が生成して靭性を低下させたり、製造過程で割れなどのトラブルが発生したり、及び／又は耐疲労特性を低下させたりする場合がある。したがって、Ａｌ含有量は５．０００％以下である。Ａｌ含有量は４．５００％以下、４．０００％以下又は３．５００％以下であってもよい。とりわけ、靭性の低下を抑制するという観点からは、Ａｌ含有量は１．５００％以下、１．０００％以下又は０．３００％以下であってもよい。 [Al: 0.001-5.000%]
Aluminum (Al) is a deoxidizing element and is also an effective element for improving corrosion resistance and / or heat resistance. In order to obtain these effects, the Al content is 0.001% or more. The Al content may be 0.010% or more, 0.100% or more, or 0.200% or more. In particular, from the viewpoint of sufficiently improving the heat resistance, the Al content may be 1.000% or more, 2.000% or more, or 3.000% or more. On the other hand, if Al is excessively contained, coarse inclusions may be generated to reduce toughness, troubles such as cracking may occur in the manufacturing process, and / or fatigue resistance may be deteriorated. .. Therefore, the Al content is 5.000% or less. The Al content may be 4.500% or less, 4000% or less, or 3.500% or less. In particular, from the viewpoint of suppressing the decrease in toughness, the Al content may be 1.500% or less, 1.000% or less, or 0.300% or less.
アルミニウム（Ａｌ）は、脱酸元素であり、耐食性及び／又は耐熱性を向上させるのに有効な元素でもある。これらの効果を得るために、Ａｌ含有量は０．００１％以上である。Ａｌ含有量は０．０１０％以上、０．１００％以上又は０．２００％以上であってもよい。とりわけ、耐熱性を十分に向上させる観点からは、Ａｌ含有量は１．０００％以上、２．０００％以上又は３．０００％以上であってもよい。一方で、Ａｌを過度に含有すると、粗大な介在物が生成して靭性を低下させたり、製造過程で割れなどのトラブルが発生したり、及び／又は耐疲労特性を低下させたりする場合がある。したがって、Ａｌ含有量は５．０００％以下である。Ａｌ含有量は４．５００％以下、４．０００％以下又は３．５００％以下であってもよい。とりわけ、靭性の低下を抑制するという観点からは、Ａｌ含有量は１．５００％以下、１．０００％以下又は０．３００％以下であってもよい。 [Al: 0.001-5.000%]
Aluminum (Al) is a deoxidizing element and is also an effective element for improving corrosion resistance and / or heat resistance. In order to obtain these effects, the Al content is 0.001% or more. The Al content may be 0.010% or more, 0.100% or more, or 0.200% or more. In particular, from the viewpoint of sufficiently improving the heat resistance, the Al content may be 1.000% or more, 2.000% or more, or 3.000% or more. On the other hand, if Al is excessively contained, coarse inclusions may be generated to reduce toughness, troubles such as cracking may occur in the manufacturing process, and / or fatigue resistance may be deteriorated. .. Therefore, the Al content is 5.000% or less. The Al content may be 4.500% or less, 4000% or less, or 3.500% or less. In particular, from the viewpoint of suppressing the decrease in toughness, the Al content may be 1.500% or less, 1.000% or less, or 0.300% or less.
［Ｎ：０．２０００％以下］
窒素（Ｎ）は製造工程で混入する元素であり、本発明の実施形態に係るＸ元素との間で形成される介在物を低減する観点からは少ないほど好ましく、よってＮ含有量は０％であってもよい。しかしながら、Ｎ含有量を０．０００１％未満に低減するためには精錬に時間を要し、生産性の低下を招く。したがって、Ｎ含有量は０．０００１％以上、０．０００５％以上又は０．００１０％以上であってもよい。一方で、Ｎはオーステナイトの安定化に有効な元素でもあり、必要に応じて意図的に含有させてもよい。この場合には、Ｎ含有量は０．０１００％以上であることが好ましく、０．０２００％以上、０．０５００％以上であってもよい。しかしながら、Ｎを過度に含有すると、Ｘ元素の有効量が低下するとともに、靭性が低下する場合がある。したがって、Ｎ含有量は０．２０００％以下である。Ｎ含有量は０．１５００％以下、０．１０００％以下又は０．０８００％以下であってもよい。 [N: 0.2000% or less]
Nitrogen (N) is an element mixed in the manufacturing process, and is preferable from the viewpoint of reducing inclusions formed with the X element according to the embodiment of the present invention, so that the N content is 0%. There may be. However, in order to reduce the N content to less than 0.0001%, it takes time for refining, which leads to a decrease in productivity. Therefore, the N content may be 0.0001% or more, 0.0005% or more, or 0.0010% or more. On the other hand, N is also an element effective for stabilizing austenite, and may be intentionally contained if necessary. In this case, the N content is preferably 0.0100% or more, and may be 0.0200% or more and 0.0500% or more. However, if N is excessively contained, the effective amount of the X element may decrease and the toughness may decrease. Therefore, the N content is 0.2000% or less. The N content may be 0.1500% or less, 0.1000% or less, or 0.0800% or less.
窒素（Ｎ）は製造工程で混入する元素であり、本発明の実施形態に係るＸ元素との間で形成される介在物を低減する観点からは少ないほど好ましく、よってＮ含有量は０％であってもよい。しかしながら、Ｎ含有量を０．０００１％未満に低減するためには精錬に時間を要し、生産性の低下を招く。したがって、Ｎ含有量は０．０００１％以上、０．０００５％以上又は０．００１０％以上であってもよい。一方で、Ｎはオーステナイトの安定化に有効な元素でもあり、必要に応じて意図的に含有させてもよい。この場合には、Ｎ含有量は０．０１００％以上であることが好ましく、０．０２００％以上、０．０５００％以上であってもよい。しかしながら、Ｎを過度に含有すると、Ｘ元素の有効量が低下するとともに、靭性が低下する場合がある。したがって、Ｎ含有量は０．２０００％以下である。Ｎ含有量は０．１５００％以下、０．１０００％以下又は０．０８００％以下であってもよい。 [N: 0.2000% or less]
Nitrogen (N) is an element mixed in the manufacturing process, and is preferable from the viewpoint of reducing inclusions formed with the X element according to the embodiment of the present invention, so that the N content is 0%. There may be. However, in order to reduce the N content to less than 0.0001%, it takes time for refining, which leads to a decrease in productivity. Therefore, the N content may be 0.0001% or more, 0.0005% or more, or 0.0010% or more. On the other hand, N is also an element effective for stabilizing austenite, and may be intentionally contained if necessary. In this case, the N content is preferably 0.0100% or more, and may be 0.0200% or more and 0.0500% or more. However, if N is excessively contained, the effective amount of the X element may decrease and the toughness may decrease. Therefore, the N content is 0.2000% or less. The N content may be 0.1500% or less, 0.1000% or less, or 0.0800% or less.
［Ｏ：０．０１００％以下］
酸素（Ｏ）は製造工程で混入する元素であり、本発明の実施形態に係るＸ元素との間で形成される介在物を低減する観点からは少ないほど好ましく、よってＯ含有量は０％であってもよい。しかしながら、Ｏ含有量を０．０００１％未満に低減するためには精錬に時間を要し、生産性の低下を招く。したがって、Ｏ含有量は０．０００１％以上、０．０００５％以上又は０．００１０％以上であってもよい。一方で、Ｏを過度に含有すると、粗大な介在物が形成され、Ｘ元素の有効量が低下するとともに、鋼材の成形性及び／又は靭性が低下する場合がある。したがって、Ｏ含有量は０．０１００％以下である。Ｏ含有量は０．００８０％以下、０．００６０％以下又は０．００４０％以下であってもよい。 [O: 0.0100% or less]
Oxygen (O) is an element mixed in the manufacturing process, and is preferable from the viewpoint of reducing inclusions formed with the X element according to the embodiment of the present invention, so that the O content is 0%. There may be. However, in order to reduce the O content to less than 0.0001%, it takes time for refining, which leads to a decrease in productivity. Therefore, the O content may be 0.0001% or more, 0.0005% or more, or 0.0010% or more. On the other hand, if O is excessively contained, coarse inclusions may be formed, the effective amount of the X element may be lowered, and the formability and / or toughness of the steel material may be lowered. Therefore, the O content is 0.0100% or less. The O content may be 0.0080% or less, 0.0060% or less, or 0.0040% or less.
酸素（Ｏ）は製造工程で混入する元素であり、本発明の実施形態に係るＸ元素との間で形成される介在物を低減する観点からは少ないほど好ましく、よってＯ含有量は０％であってもよい。しかしながら、Ｏ含有量を０．０００１％未満に低減するためには精錬に時間を要し、生産性の低下を招く。したがって、Ｏ含有量は０．０００１％以上、０．０００５％以上又は０．００１０％以上であってもよい。一方で、Ｏを過度に含有すると、粗大な介在物が形成され、Ｘ元素の有効量が低下するとともに、鋼材の成形性及び／又は靭性が低下する場合がある。したがって、Ｏ含有量は０．０１００％以下である。Ｏ含有量は０．００８０％以下、０．００６０％以下又は０．００４０％以下であってもよい。 [O: 0.0100% or less]
Oxygen (O) is an element mixed in the manufacturing process, and is preferable from the viewpoint of reducing inclusions formed with the X element according to the embodiment of the present invention, so that the O content is 0%. There may be. However, in order to reduce the O content to less than 0.0001%, it takes time for refining, which leads to a decrease in productivity. Therefore, the O content may be 0.0001% or more, 0.0005% or more, or 0.0010% or more. On the other hand, if O is excessively contained, coarse inclusions may be formed, the effective amount of the X element may be lowered, and the formability and / or toughness of the steel material may be lowered. Therefore, the O content is 0.0100% or less. The O content may be 0.0080% or less, 0.0060% or less, or 0.0040% or less.
［Ｐｒ：０～０．８０００％、Ｓｍ：０～０．８０００％、Ｅｕ：０～０．８０００％、Ｇｄ：０～０．８０００％、Ｔｂ：０～０．８０００％、Ｄｙ：０～０．８０００％、Ｈｏ：０～０．８０００％、Ｅｒ：０～０．８０００％、Ｔｍ：０～０．８０００％、Ｙｂ：０～０．８０００％、Ｌｕ：０～０．８０００％、及びＳｃ：０～０．８０００％からなる群より選択される少なくとも１種のＸ元素］
本発明の実施形態に係るＸ元素は、Ｐｒ：０～０．８０００％、Ｓｍ：０～０．８０００％、Ｅｕ：０～０．８０００％、Ｇｄ：０～０．８０００％、Ｔｂ：０～０．８０００％、Ｄｙ：０～０．８０００％、Ｈｏ：０～０．８０００％、Ｅｒ：０～０．８０００％、Ｔｍ：０～０．８０００％、Ｙｂ：０～０．８０００％、Ｌｕ：０～０．８０００％、及びＳｃ：０～０．８０００％であり、プラセオジム（Ｐｒ）、サマリウム（Ｓｍ）、ユウロピウム（Ｅｕ）、ガドリニウム（Ｇｄ）、テルビウム（Ｔｂ）、ジスプロシウム（Ｄｙ）、ホルミウム（Ｈｏ）、エルビウム（Ｅｒ）、ツリウム（Ｔｍ）、イッテルビウム（Ｙｂ）、ルテチウム（Ｌｕ）、及びスカンジウム（Ｓｃ）はリン化物の形成に基づくピン止め効果を発現することができる。当該ピン止め効果を発現することで、金属組織の粒成長を顕著に抑制することが可能となる。 [Pr: 0 to 0.8000%, Sm: 0 to 0.8000%, Eu: 0 to 0.8000%, Gd: 0 to 0.8000%, Tb: 0 to 0.8000%, Dy: 0 to 0.8000%, Ho: 0 to 0.8000%, Er: 0 to 0.8000%, Tm: 0 to 0.8000%, Yb: 0 to 0.8000%, Lu: 0 to 0.8000%, And Sc: at least one X element selected from the group consisting of 0 to 0.8000%]
The element X according to the embodiment of the present invention is Pr: 0 to 0.8000%, Sm: 0 to 0.8000%, Eu: 0 to 0.8000%, Gd: 0 to 0.8000%, Tb: 0. ~ 0.8000%, Dy: 0 to 0.8000%, Ho: 0 to 0.8000%, Er: 0 to 0.8000%, Tm: 0 to 0.8000%, Yb: 0 to 0.8000% , Lu: 0 to 0.8000%, and Sc: 0 to 0.8000%, and are placeodim (Pr), samarium (Sm), europium (Eu), lutetium (Gd), terbium (Tb), dysprosium (Dy). ), Holmium (Ho), Elbium (Er), Thurium (Tm), Itterbium (Yb), Lutetium (Lu), and Scandium (Sc) can exhibit a pinning effect based on the formation of phosphonic acid. By exhibiting the pinning effect, it becomes possible to remarkably suppress the grain growth of the metal structure.
本発明の実施形態に係るＸ元素は、Ｐｒ：０～０．８０００％、Ｓｍ：０～０．８０００％、Ｅｕ：０～０．８０００％、Ｇｄ：０～０．８０００％、Ｔｂ：０～０．８０００％、Ｄｙ：０～０．８０００％、Ｈｏ：０～０．８０００％、Ｅｒ：０～０．８０００％、Ｔｍ：０～０．８０００％、Ｙｂ：０～０．８０００％、Ｌｕ：０～０．８０００％、及びＳｃ：０～０．８０００％であり、プラセオジム（Ｐｒ）、サマリウム（Ｓｍ）、ユウロピウム（Ｅｕ）、ガドリニウム（Ｇｄ）、テルビウム（Ｔｂ）、ジスプロシウム（Ｄｙ）、ホルミウム（Ｈｏ）、エルビウム（Ｅｒ）、ツリウム（Ｔｍ）、イッテルビウム（Ｙｂ）、ルテチウム（Ｌｕ）、及びスカンジウム（Ｓｃ）はリン化物の形成に基づくピン止め効果を発現することができる。当該ピン止め効果を発現することで、金属組織の粒成長を顕著に抑制することが可能となる。 [Pr: 0 to 0.8000%, Sm: 0 to 0.8000%, Eu: 0 to 0.8000%, Gd: 0 to 0.8000%, Tb: 0 to 0.8000%, Dy: 0 to 0.8000%, Ho: 0 to 0.8000%, Er: 0 to 0.8000%, Tm: 0 to 0.8000%, Yb: 0 to 0.8000%, Lu: 0 to 0.8000%, And Sc: at least one X element selected from the group consisting of 0 to 0.8000%]
The element X according to the embodiment of the present invention is Pr: 0 to 0.8000%, Sm: 0 to 0.8000%, Eu: 0 to 0.8000%, Gd: 0 to 0.8000%, Tb: 0. ~ 0.8000%, Dy: 0 to 0.8000%, Ho: 0 to 0.8000%, Er: 0 to 0.8000%, Tm: 0 to 0.8000%, Yb: 0 to 0.8000% , Lu: 0 to 0.8000%, and Sc: 0 to 0.8000%, and are placeodim (Pr), samarium (Sm), europium (Eu), lutetium (Gd), terbium (Tb), dysprosium (Dy). ), Holmium (Ho), Elbium (Er), Thurium (Tm), Itterbium (Yb), Lutetium (Lu), and Scandium (Sc) can exhibit a pinning effect based on the formation of phosphonic acid. By exhibiting the pinning effect, it becomes possible to remarkably suppress the grain growth of the metal structure.
上記Ｘ元素は、いずれか１つの元素を単独で使用してもよいし、又は上記元素のうち２種以上のあらゆる特定の組み合わせにおいて使用してもよい。また、当該Ｘ元素は、後で詳しく説明する式１を満たす量において存在すればよく、その下限値は特に限定されない。しかしながら、例えば、各Ｘ元素の含有量又は合計の含有量は０．００１０％以上であってもよく、好ましくは０．００５０％以上であり、より好ましくは０．０１５０％以上であり、さらにより好ましくは０．０３００％以上であり、最も好ましくは０．０５００％以上である。一方で、Ｘ元素を過度に含有しても効果が飽和し、それゆえ当該Ｘ元素を必要以上に鋼材中に含有させることは製造コストの上昇を招く虞がある。したがって、各Ｘ元素の含有量は０．８０００％以下であり、例えば０．７０００％以下、０．６０００％以下、０．５０００％以下、０．４０００％以下又は０．３０００％以下であってもよい。また、Ｘ元素の含有量の合計は９．６０００％以下であり、例えば６．００００％以下、５．００００％以下、４．００００％以下、２．００００％以下、１．００００％以下又は０．５０００％以下であってもよい。
The X element may be used alone or in any specific combination of two or more of the above elements. Further, the element X may be present in an amount satisfying Equation 1, which will be described in detail later, and the lower limit thereof is not particularly limited. However, for example, the content of each X element or the total content may be 0.0010% or more, preferably 0.0050% or more, more preferably 0.0150% or more, and even more. It is preferably 0.0300% or more, and most preferably 0.0500% or more. On the other hand, even if the X element is excessively contained, the effect is saturated, and therefore, if the X element is contained in the steel material more than necessary, the manufacturing cost may increase. Therefore, the content of each X element is 0.8000% or less, for example, 0.7000% or less, 0.6000% or less, 0.5000% or less, 0.4000% or less, or 0.3000% or less. May be good. The total content of element X is 9.6000% or less, for example, 6.00% or less, 5.0000% or less, 4.00% or less, 2.0000% or less, 1.0000% or less or 0. It may be 5000% or less.
本発明の実施形態に係る鋼材の基本化学組成は上記のとおりである。さらに、当該鋼材は、必要に応じて以下の任意選択元素のうち１種又は２種以上を含有してもよい。例えば、鋼材は、Ｎｂ：０～３．０００％、Ｔｉ：０～０．５００％、Ｔａ：０～０．５００％、Ｖ：０～１．００％、Ｃｕ：０～３．００％、Ｎｉ：０～６０．００％、Ｃｒ：０～３０．００％、Ｍｏ：０～５．００％、Ｗ：０～２．００％、Ｂ：０～０．０２００％、Ｃｏ：０～３．００％、Ｂｅ：０～０．０５０％、及びＡｇ：０～０．５００％のうち１種又は２種以上を含有してもよい。また、鋼材は、Ｚｒ：０～０．５０００％、Ｈｆ：０～０．５０００％、Ｃａ：０～０．０５００％、Ｍｇ：０～０．０５００％、並びにＬａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種：合計で０～０．５０００％のうち１種又は２種以上を含有してもよい。また、鋼材は、Ｓｎ：０～０．３００％、及びＳｂ：０～０．３００％のうち１種又は２種を含有してもよい。また、鋼材は、Ｔｅ：０～０．１００％、Ｓｅ：０～０．１００％、Ａｓ：０～０．０５０％、Ｂｉ：０～０．５００％、及びＰｂ：０～０．５００％のうち１種又は２種以上を含有してもよい。以下、これらの任意選択元素について詳しく説明する。
The basic chemical composition of the steel material according to the embodiment of the present invention is as described above. Further, the steel material may contain one or more of the following optional elements, if necessary. For example, the steel material has Nb: 0 to 3.000%, Ti: 0 to 0.500%, Ta: 0 to 0.500%, V: 0 to 1.00%, Cu: 0 to 3.00%, Ni: 0 to 60.00%, Cr: 0 to 30.00%, Mo: 0 to 5.00%, W: 0 to 2.00%, B: 0 to 0.0200%, Co: 0 to 3 It may contain one or more of 0.00%, Be: 0 to 0.050%, and Ag: 0 to 0.500%. The steel materials include Zr: 0 to 0.5000%, Hf: 0 to 0.5000%, Ca: 0 to 0.0500%, Mg: 0 to 0.0500%, and La, Ce, Nd, Pm and At least one of Y: One or more of 0 to 0.5000% in total may be contained. Further, the steel material may contain one or two of Sn: 0 to 0.300% and Sb: 0 to 0.300%. The steel materials are Te: 0 to 0.100%, Se: 0 to 0.100%, As: 0 to 0.050%, Bi: 0 to 0.500%, and Pb: 0 to 0.500%. One or more of them may be contained. Hereinafter, these optional elements will be described in detail.
［Ｎｂ：０～３．０００％］
ニオブ（Ｎｂ）は、析出強化及び再結晶の抑制等に寄与する元素である。Ｎｂ含有量は０％であってもよいが、これらの効果を得るためには、Ｎｂ含有量は０．００３％以上であることが好ましい。例えば、Ｎｂ含有量は０．００５％以上又は０．０１０％以上であってもよい。とりわけ、析出強化を十分に図る観点からは、Ｎｂ含有量は１．０００％以上又は１．５００％以上であってもよい。一方で、Ｎｂを過度に含有すると、効果が飽和し、加工性及び／又は靭性を低下させる場合がある。したがって、Ｎｂ含有量は３．０００％以下である。Ｎｂ含有量は２．８００％以下、２．５００％以下又は２．０００％以下であってもよい。とりわけ、溶接熱影響部（ＨＡＺ）の靭性低下を抑制するという観点からは、Ｎｂ含有量は０．１００％以下であることが好ましく、０．０８０％以下、０．０５０％以下又は０．０３０％以下であってもよい。 [Nb: 0-3.000%]
Niobium (Nb) is an element that contributes to strengthening precipitation and suppressing recrystallization. The Nb content may be 0%, but in order to obtain these effects, the Nb content is preferably 0.003% or more. For example, the Nb content may be 0.005% or more or 0.010% or more. In particular, the Nb content may be 1.000% or more or 1.500% or more from the viewpoint of sufficiently strengthening precipitation. On the other hand, if Nb is excessively contained, the effect may be saturated and the processability and / or toughness may be lowered. Therefore, the Nb content is 3.000% or less. The Nb content may be 2.800% or less, 2.500% or less, or 2.000% or less. In particular, from the viewpoint of suppressing the decrease in toughness of the weld heat affected zone (HAZ), the Nb content is preferably 0.100% or less, 0.080% or less, 0.050% or less, or 0.030. It may be less than or equal to%.
ニオブ（Ｎｂ）は、析出強化及び再結晶の抑制等に寄与する元素である。Ｎｂ含有量は０％であってもよいが、これらの効果を得るためには、Ｎｂ含有量は０．００３％以上であることが好ましい。例えば、Ｎｂ含有量は０．００５％以上又は０．０１０％以上であってもよい。とりわけ、析出強化を十分に図る観点からは、Ｎｂ含有量は１．０００％以上又は１．５００％以上であってもよい。一方で、Ｎｂを過度に含有すると、効果が飽和し、加工性及び／又は靭性を低下させる場合がある。したがって、Ｎｂ含有量は３．０００％以下である。Ｎｂ含有量は２．８００％以下、２．５００％以下又は２．０００％以下であってもよい。とりわけ、溶接熱影響部（ＨＡＺ）の靭性低下を抑制するという観点からは、Ｎｂ含有量は０．１００％以下であることが好ましく、０．０８０％以下、０．０５０％以下又は０．０３０％以下であってもよい。 [Nb: 0-3.000%]
Niobium (Nb) is an element that contributes to strengthening precipitation and suppressing recrystallization. The Nb content may be 0%, but in order to obtain these effects, the Nb content is preferably 0.003% or more. For example, the Nb content may be 0.005% or more or 0.010% or more. In particular, the Nb content may be 1.000% or more or 1.500% or more from the viewpoint of sufficiently strengthening precipitation. On the other hand, if Nb is excessively contained, the effect may be saturated and the processability and / or toughness may be lowered. Therefore, the Nb content is 3.000% or less. The Nb content may be 2.800% or less, 2.500% or less, or 2.000% or less. In particular, from the viewpoint of suppressing the decrease in toughness of the weld heat affected zone (HAZ), the Nb content is preferably 0.100% or less, 0.080% or less, 0.050% or less, or 0.030. It may be less than or equal to%.
［Ｔｉ：０～０．５００％］
チタン（Ｔｉ）は、析出強化等により鋼材の強度向上に寄与する元素である。Ｔｉ含有量は０％であってもよいが、このような効果を得るためには、Ｔｉ含有量は０．００５％以上であることが好ましい。Ｔｉ含有量は０．０１０％以上、０．０５０％以上又は０．０８０％以上であってもよい。一方で、Ｔｉを過度に含有すると、多量の析出物が生成して靭性を低下させる場合がある。したがって、Ｔｉ含有量は０．５００％以下である。Ｔｉ含有量は０．３００％以下、０．２００％以下又は０．１００％以下であってもよい。 [Ti: 0 to 0.500%]
Titanium (Ti) is an element that contributes to improving the strength of steel materials by strengthening precipitation. The Ti content may be 0%, but in order to obtain such an effect, the Ti content is preferably 0.005% or more. The Ti content may be 0.010% or more, 0.050% or more, or 0.080% or more. On the other hand, if Ti is excessively contained, a large amount of precipitates may be formed and the toughness may be lowered. Therefore, the Ti content is 0.500% or less. The Ti content may be 0.300% or less, 0.200% or less, or 0.100% or less.
チタン（Ｔｉ）は、析出強化等により鋼材の強度向上に寄与する元素である。Ｔｉ含有量は０％であってもよいが、このような効果を得るためには、Ｔｉ含有量は０．００５％以上であることが好ましい。Ｔｉ含有量は０．０１０％以上、０．０５０％以上又は０．０８０％以上であってもよい。一方で、Ｔｉを過度に含有すると、多量の析出物が生成して靭性を低下させる場合がある。したがって、Ｔｉ含有量は０．５００％以下である。Ｔｉ含有量は０．３００％以下、０．２００％以下又は０．１００％以下であってもよい。 [Ti: 0 to 0.500%]
Titanium (Ti) is an element that contributes to improving the strength of steel materials by strengthening precipitation. The Ti content may be 0%, but in order to obtain such an effect, the Ti content is preferably 0.005% or more. The Ti content may be 0.010% or more, 0.050% or more, or 0.080% or more. On the other hand, if Ti is excessively contained, a large amount of precipitates may be formed and the toughness may be lowered. Therefore, the Ti content is 0.500% or less. The Ti content may be 0.300% or less, 0.200% or less, or 0.100% or less.
［Ｔａ：０～０．５００％］
タンタル（Ｔａ）は、炭化物の形態制御と強度の増加に有効な元素である。Ｔａ含有量は０％であってもよいが、これらの効果を得るためには、Ｔａ含有量は０．００１％以上であることが好ましい。Ｔａ含有量は０．００５％以上、０．０１０％以上又は０．０５０％以上であってもよい。一方で、Ｔａを過度に含有すると、微細なＴａ炭化物が多数析出し、鋼材の過度な強度上昇を招き、結果として延性の低下及び冷間加工性を低下させる場合がある。したがって、Ｔａ含有量は０．５００％以下である。Ｔａ含有量は、０．３００％以下、０．１００％以下又は０．０８０％以下であってもよい。 [Ta: 0 to 0.500%]
Tantalum (Ta) is an element effective in controlling the morphology of carbides and increasing their strength. The Ta content may be 0%, but in order to obtain these effects, the Ta content is preferably 0.001% or more. The Ta content may be 0.005% or more, 0.010% or more, or 0.050% or more. On the other hand, if Ta is excessively contained, a large amount of fine Ta carbides may be deposited, which may lead to an excessive increase in strength of the steel material, resulting in a decrease in ductility and a decrease in cold workability. Therefore, the Ta content is 0.500% or less. The Ta content may be 0.300% or less, 0.100% or less, or 0.080% or less.
タンタル（Ｔａ）は、炭化物の形態制御と強度の増加に有効な元素である。Ｔａ含有量は０％であってもよいが、これらの効果を得るためには、Ｔａ含有量は０．００１％以上であることが好ましい。Ｔａ含有量は０．００５％以上、０．０１０％以上又は０．０５０％以上であってもよい。一方で、Ｔａを過度に含有すると、微細なＴａ炭化物が多数析出し、鋼材の過度な強度上昇を招き、結果として延性の低下及び冷間加工性を低下させる場合がある。したがって、Ｔａ含有量は０．５００％以下である。Ｔａ含有量は、０．３００％以下、０．１００％以下又は０．０８０％以下であってもよい。 [Ta: 0 to 0.500%]
Tantalum (Ta) is an element effective in controlling the morphology of carbides and increasing their strength. The Ta content may be 0%, but in order to obtain these effects, the Ta content is preferably 0.001% or more. The Ta content may be 0.005% or more, 0.010% or more, or 0.050% or more. On the other hand, if Ta is excessively contained, a large amount of fine Ta carbides may be deposited, which may lead to an excessive increase in strength of the steel material, resulting in a decrease in ductility and a decrease in cold workability. Therefore, the Ta content is 0.500% or less. The Ta content may be 0.300% or less, 0.100% or less, or 0.080% or less.
［Ｖ：０～１．００％］
バナジウム（Ｖ）は、析出強化等により鋼材の強度向上に寄与する元素である。Ｖ含有量は０％であってもよいが、このような効果を得るためには、Ｖ含有量は０．００１％以上であることが好ましい。Ｖ含有量は０．０１％以上、０．０２％以上、０．０５％以上又は０．１０％以上であってもよい。一方で、Ｖを過度に含有すると、多量の析出物が生成して靭性を低下させる場合がある。したがって、Ｖ含有量は１．００％以下である。Ｖ含有量は０．８０％以下、０．６０％以下又は０．５０％以下であってもよい。 [V: 0 to 1.00%]
Vanadium (V) is an element that contributes to improving the strength of steel materials by strengthening precipitation. The V content may be 0%, but in order to obtain such an effect, the V content is preferably 0.001% or more. The V content may be 0.01% or more, 0.02% or more, 0.05% or more, or 0.10% or more. On the other hand, if V is excessively contained, a large amount of precipitates may be formed and the toughness may be lowered. Therefore, the V content is 1.00% or less. The V content may be 0.80% or less, 0.60% or less, or 0.50% or less.
バナジウム（Ｖ）は、析出強化等により鋼材の強度向上に寄与する元素である。Ｖ含有量は０％であってもよいが、このような効果を得るためには、Ｖ含有量は０．００１％以上であることが好ましい。Ｖ含有量は０．０１％以上、０．０２％以上、０．０５％以上又は０．１０％以上であってもよい。一方で、Ｖを過度に含有すると、多量の析出物が生成して靭性を低下させる場合がある。したがって、Ｖ含有量は１．００％以下である。Ｖ含有量は０．８０％以下、０．６０％以下又は０．５０％以下であってもよい。 [V: 0 to 1.00%]
Vanadium (V) is an element that contributes to improving the strength of steel materials by strengthening precipitation. The V content may be 0%, but in order to obtain such an effect, the V content is preferably 0.001% or more. The V content may be 0.01% or more, 0.02% or more, 0.05% or more, or 0.10% or more. On the other hand, if V is excessively contained, a large amount of precipitates may be formed and the toughness may be lowered. Therefore, the V content is 1.00% or less. The V content may be 0.80% or less, 0.60% or less, or 0.50% or less.
［Ｃｕ：０～３．００％］
銅（Ｃｕ）は強度及び／又は耐食性の向上に寄与する元素である。Ｃｕ含有量は０％であってもよいが、これらの効果を得るためには、Ｃｕ含有量は０．００１％以上であることが好ましい。Ｃｕ含有量は０．０１％以上、０．１０％以上、０．１５％以上、０．２０％以上又は０．３０％以上であってもよい。一方で、Ｃｕを過度に含有すると、靭性や溶接性の劣化を招く場合がある。したがって、Ｃｕ含有量は３．００％以下である。Ｃｕ含有量は２．００％以下、１．５０％以下、１．００％以下又は０．５０％以下であってもよい。 [Cu: 0 to 3.00%]
Copper (Cu) is an element that contributes to the improvement of strength and / or corrosion resistance. The Cu content may be 0%, but in order to obtain these effects, the Cu content is preferably 0.001% or more. The Cu content may be 0.01% or more, 0.10% or more, 0.15% or more, 0.20% or more, or 0.30% or more. On the other hand, if Cu is excessively contained, the toughness and weldability may be deteriorated. Therefore, the Cu content is 3.00% or less. The Cu content may be 2.00% or less, 1.50% or less, 1.00% or less, or 0.50% or less.
銅（Ｃｕ）は強度及び／又は耐食性の向上に寄与する元素である。Ｃｕ含有量は０％であってもよいが、これらの効果を得るためには、Ｃｕ含有量は０．００１％以上であることが好ましい。Ｃｕ含有量は０．０１％以上、０．１０％以上、０．１５％以上、０．２０％以上又は０．３０％以上であってもよい。一方で、Ｃｕを過度に含有すると、靭性や溶接性の劣化を招く場合がある。したがって、Ｃｕ含有量は３．００％以下である。Ｃｕ含有量は２．００％以下、１．５０％以下、１．００％以下又は０．５０％以下であってもよい。 [Cu: 0 to 3.00%]
Copper (Cu) is an element that contributes to the improvement of strength and / or corrosion resistance. The Cu content may be 0%, but in order to obtain these effects, the Cu content is preferably 0.001% or more. The Cu content may be 0.01% or more, 0.10% or more, 0.15% or more, 0.20% or more, or 0.30% or more. On the other hand, if Cu is excessively contained, the toughness and weldability may be deteriorated. Therefore, the Cu content is 3.00% or less. The Cu content may be 2.00% or less, 1.50% or less, 1.00% or less, or 0.50% or less.
［Ｎｉ：０～６０．００％］
ニッケル（Ｎｉ）は強度及び／又は耐熱性の向上に寄与する元素であり、有効なオーステナイト安定化元素でもある。Ｎｉ含有量は０％であってもよいが、これらの効果を得るためには、Ｎｉ含有量は０．００１％以上であることが好ましい。Ｎｉ含有量は０．０１％以上、０．１０％以上、０．５０％以上、０．７０％以上、１．００％以上又は３．００％以上であってもよい。とりわけ、耐熱性を十分に向上させる観点からは、Ｎｉ含有量は３０．００％以上、３５．００％以上又は４０．００％以上であってもよい。一方で、Ｎｉを過度に含有すると、合金コストの増加に加えて熱間加工時の変形抵抗が増大し、設備負荷が大きくなる場合がある。したがって、Ｎｉ含有量は６０．００％以下である。Ｎｉ含有量は５５．００％以下又は５０．００％以下であってもよい。とりわけ、経済性の観点及び／又は溶接性の低下を抑制するという観点からは、Ｎｉ含有量は１５．００％以下、１０．００％以下、６．００％以下又は４．００％以下であってもよい。 [Ni: 0-60.00%]
Nickel (Ni) is an element that contributes to the improvement of strength and / or heat resistance, and is also an effective austenite stabilizing element. The Ni content may be 0%, but in order to obtain these effects, the Ni content is preferably 0.001% or more. The Ni content may be 0.01% or more, 0.10% or more, 0.50% or more, 0.70% or more, 1.00% or more, or 3.00% or more. In particular, from the viewpoint of sufficiently improving the heat resistance, the Ni content may be 30.00% or more, 35.00% or more, or 40.00% or more. On the other hand, if Ni is excessively contained, the deformation resistance during hot working increases in addition to the increase in alloy cost, which may increase the equipment load. Therefore, the Ni content is 60.00% or less. The Ni content may be 55.00% or less or 50.00% or less. In particular, from the viewpoint of economic efficiency and / or from the viewpoint of suppressing deterioration of weldability, the Ni content is 15.00% or less, 10.00% or less, 6.00% or less, or 4.00% or less. You may.
ニッケル（Ｎｉ）は強度及び／又は耐熱性の向上に寄与する元素であり、有効なオーステナイト安定化元素でもある。Ｎｉ含有量は０％であってもよいが、これらの効果を得るためには、Ｎｉ含有量は０．００１％以上であることが好ましい。Ｎｉ含有量は０．０１％以上、０．１０％以上、０．５０％以上、０．７０％以上、１．００％以上又は３．００％以上であってもよい。とりわけ、耐熱性を十分に向上させる観点からは、Ｎｉ含有量は３０．００％以上、３５．００％以上又は４０．００％以上であってもよい。一方で、Ｎｉを過度に含有すると、合金コストの増加に加えて熱間加工時の変形抵抗が増大し、設備負荷が大きくなる場合がある。したがって、Ｎｉ含有量は６０．００％以下である。Ｎｉ含有量は５５．００％以下又は５０．００％以下であってもよい。とりわけ、経済性の観点及び／又は溶接性の低下を抑制するという観点からは、Ｎｉ含有量は１５．００％以下、１０．００％以下、６．００％以下又は４．００％以下であってもよい。 [Ni: 0-60.00%]
Nickel (Ni) is an element that contributes to the improvement of strength and / or heat resistance, and is also an effective austenite stabilizing element. The Ni content may be 0%, but in order to obtain these effects, the Ni content is preferably 0.001% or more. The Ni content may be 0.01% or more, 0.10% or more, 0.50% or more, 0.70% or more, 1.00% or more, or 3.00% or more. In particular, from the viewpoint of sufficiently improving the heat resistance, the Ni content may be 30.00% or more, 35.00% or more, or 40.00% or more. On the other hand, if Ni is excessively contained, the deformation resistance during hot working increases in addition to the increase in alloy cost, which may increase the equipment load. Therefore, the Ni content is 60.00% or less. The Ni content may be 55.00% or less or 50.00% or less. In particular, from the viewpoint of economic efficiency and / or from the viewpoint of suppressing deterioration of weldability, the Ni content is 15.00% or less, 10.00% or less, 6.00% or less, or 4.00% or less. You may.
［Ｃｒ：０～３０．００％］
クロム（Ｃｒ）は強度及び／又は耐食性の向上に寄与する元素である。Ｃｒ含有量は０％であってもよいが、これらの効果を得るためには、Ｃｒ含有量は０．００１％以上であることが好ましい。Ｃｒ含有量は０．０１％以上、０．０５％以上、０．１０％以上又は０．５０％以上であってもよい。とりわけ、耐食性を十分に向上させる観点からは、Ｃｒ含有量は１０．００％以上、１２．００％以上又は１５．００％以上であってもよい。一方で、Ｃｒを過度に含有すると、合金コストの増加に加えて靭性が低下する場合がある。したがって、Ｃｒ含有量は３０．００％以下である。Ｃｒ含有量は２８．００％以下、２５．００％以下又は２０．００％以下であってもよい。とりわけ、溶接性及び／又は加工性の低下を抑制するという観点からは、Ｃｒ含有量は１０．００％以下、９．００％以下又は７．５０％以下であってもよい。 [Cr: 0 to 30.00%]
Chromium (Cr) is an element that contributes to the improvement of strength and / or corrosion resistance. The Cr content may be 0%, but in order to obtain these effects, the Cr content is preferably 0.001% or more. The Cr content may be 0.01% or more, 0.05% or more, 0.10% or more, or 0.50% or more. In particular, from the viewpoint of sufficiently improving the corrosion resistance, the Cr content may be 10.00% or more, 12.00% or more, or 15.00% or more. On the other hand, if Cr is excessively contained, the toughness may decrease in addition to the increase in alloy cost. Therefore, the Cr content is 30.00% or less. The Cr content may be 28.00% or less, 25.00% or less, or 20.00% or less. In particular, from the viewpoint of suppressing deterioration of weldability and / or processability, the Cr content may be 10.00% or less, 9.00% or less, or 7.50% or less.
クロム（Ｃｒ）は強度及び／又は耐食性の向上に寄与する元素である。Ｃｒ含有量は０％であってもよいが、これらの効果を得るためには、Ｃｒ含有量は０．００１％以上であることが好ましい。Ｃｒ含有量は０．０１％以上、０．０５％以上、０．１０％以上又は０．５０％以上であってもよい。とりわけ、耐食性を十分に向上させる観点からは、Ｃｒ含有量は１０．００％以上、１２．００％以上又は１５．００％以上であってもよい。一方で、Ｃｒを過度に含有すると、合金コストの増加に加えて靭性が低下する場合がある。したがって、Ｃｒ含有量は３０．００％以下である。Ｃｒ含有量は２８．００％以下、２５．００％以下又は２０．００％以下であってもよい。とりわけ、溶接性及び／又は加工性の低下を抑制するという観点からは、Ｃｒ含有量は１０．００％以下、９．００％以下又は７．５０％以下であってもよい。 [Cr: 0 to 30.00%]
Chromium (Cr) is an element that contributes to the improvement of strength and / or corrosion resistance. The Cr content may be 0%, but in order to obtain these effects, the Cr content is preferably 0.001% or more. The Cr content may be 0.01% or more, 0.05% or more, 0.10% or more, or 0.50% or more. In particular, from the viewpoint of sufficiently improving the corrosion resistance, the Cr content may be 10.00% or more, 12.00% or more, or 15.00% or more. On the other hand, if Cr is excessively contained, the toughness may decrease in addition to the increase in alloy cost. Therefore, the Cr content is 30.00% or less. The Cr content may be 28.00% or less, 25.00% or less, or 20.00% or less. In particular, from the viewpoint of suppressing deterioration of weldability and / or processability, the Cr content may be 10.00% or less, 9.00% or less, or 7.50% or less.
［Ｍｏ：０～５．００％］
モリブデン（Ｍｏ）は鋼の焼入れ性を高め、強度の向上に寄与する元素であり、耐食性の向上にも寄与する元素である。Ｍｏ含有量は０％であってもよいが、これらの効果を得るためには、Ｍｏ含有量は０．００１％以上であることが好ましい。Ｍｏ含有量は０．０１％以上、０．０２％以上、０．５０％以上又は１．００％以上であってもよい。一方で、Ｍｏを過度に含有すると、熱間加工時の変形抵抗が増大し、設備負荷が大きくなる場合がある。したがって、Ｍｏ含有量は５．００％以下である。Ｍｏ含有量は４．５０％以下、４．００％以下、３．００以下又は１．５０％以下であってもよい。 [Mo: 0 to 5.00%]
Molybdenum (Mo) is an element that enhances the hardenability of steel and contributes to the improvement of strength, and is also an element that contributes to the improvement of corrosion resistance. The Mo content may be 0%, but in order to obtain these effects, the Mo content is preferably 0.001% or more. The Mo content may be 0.01% or more, 0.02% or more, 0.50% or more, or 1.00% or more. On the other hand, if Mo is excessively contained, the deformation resistance during hot working increases, and the equipment load may increase. Therefore, the Mo content is 5.00% or less. The Mo content may be 4.50% or less, 4.00% or less, 3.00 or less, or 1.50% or less.
モリブデン（Ｍｏ）は鋼の焼入れ性を高め、強度の向上に寄与する元素であり、耐食性の向上にも寄与する元素である。Ｍｏ含有量は０％であってもよいが、これらの効果を得るためには、Ｍｏ含有量は０．００１％以上であることが好ましい。Ｍｏ含有量は０．０１％以上、０．０２％以上、０．５０％以上又は１．００％以上であってもよい。一方で、Ｍｏを過度に含有すると、熱間加工時の変形抵抗が増大し、設備負荷が大きくなる場合がある。したがって、Ｍｏ含有量は５．００％以下である。Ｍｏ含有量は４．５０％以下、４．００％以下、３．００以下又は１．５０％以下であってもよい。 [Mo: 0 to 5.00%]
Molybdenum (Mo) is an element that enhances the hardenability of steel and contributes to the improvement of strength, and is also an element that contributes to the improvement of corrosion resistance. The Mo content may be 0%, but in order to obtain these effects, the Mo content is preferably 0.001% or more. The Mo content may be 0.01% or more, 0.02% or more, 0.50% or more, or 1.00% or more. On the other hand, if Mo is excessively contained, the deformation resistance during hot working increases, and the equipment load may increase. Therefore, the Mo content is 5.00% or less. The Mo content may be 4.50% or less, 4.00% or less, 3.00 or less, or 1.50% or less.
［Ｗ：０～２．００％］
タングステン（Ｗ）は鋼の焼入れ性を高め、強度の向上に寄与する元素である。Ｗ含有量は０％であってもよいが、このような効果を得るためには、Ｗ含有量は０．００１％以上であることが好ましい。Ｗ含有量は０．０１％以上、０．０２％以上、０．０５％以上、０．１０％以上又は０．５０％以上であってもよい。一方で、Ｗを過度に含有すると、延性や溶接性が低下する場合がある。したがって、Ｗ含有量は２．００％以下である。Ｗ含有量は１．８０％以下、１．５０％以下又は１．００％以下であってもよい。 [W: 0 to 2.00%]
Tungsten (W) is an element that enhances the hardenability of steel and contributes to the improvement of strength. The W content may be 0%, but in order to obtain such an effect, the W content is preferably 0.001% or more. The W content may be 0.01% or more, 0.02% or more, 0.05% or more, 0.10% or more, or 0.50% or more. On the other hand, if W is excessively contained, ductility and weldability may decrease. Therefore, the W content is 2.00% or less. The W content may be 1.80% or less, 1.50% or less, or 1.00% or less.
タングステン（Ｗ）は鋼の焼入れ性を高め、強度の向上に寄与する元素である。Ｗ含有量は０％であってもよいが、このような効果を得るためには、Ｗ含有量は０．００１％以上であることが好ましい。Ｗ含有量は０．０１％以上、０．０２％以上、０．０５％以上、０．１０％以上又は０．５０％以上であってもよい。一方で、Ｗを過度に含有すると、延性や溶接性が低下する場合がある。したがって、Ｗ含有量は２．００％以下である。Ｗ含有量は１．８０％以下、１．５０％以下又は１．００％以下であってもよい。 [W: 0 to 2.00%]
Tungsten (W) is an element that enhances the hardenability of steel and contributes to the improvement of strength. The W content may be 0%, but in order to obtain such an effect, the W content is preferably 0.001% or more. The W content may be 0.01% or more, 0.02% or more, 0.05% or more, 0.10% or more, or 0.50% or more. On the other hand, if W is excessively contained, ductility and weldability may decrease. Therefore, the W content is 2.00% or less. The W content may be 1.80% or less, 1.50% or less, or 1.00% or less.
［Ｂ：０～０．０２００％］
ホウ素（Ｂ）は強度の向上に寄与する元素である。Ｂ含有量は０％であってもよいが、このような効果を得るためには、Ｂ含有量は０．０００１％以上であることが好ましい。Ｂ含有量は０．０００３％以上、０．０００５％以上又は０．０００７％以上であってもよい。一方で、Ｂを過度に含有すると、靭性及び／又は溶接性が低下する場合がある。したがって、Ｂ含有量は０．０２００％以下である。Ｂ含有量は０．０１００％以下、０．００５０％以下、０．００３０％以下又は０．００２０％以下であってもよい。 [B: 0 to 0.0200%]
Boron (B) is an element that contributes to the improvement of strength. The B content may be 0%, but in order to obtain such an effect, the B content is preferably 0.0001% or more. The B content may be 0.0003% or more, 0.0005% or more, or 0.0007% or more. On the other hand, if B is excessively contained, toughness and / or weldability may decrease. Therefore, the B content is 0.0200% or less. The B content may be 0.0100% or less, 0.0050% or less, 0.0030% or less, or 0.0020% or less.
ホウ素（Ｂ）は強度の向上に寄与する元素である。Ｂ含有量は０％であってもよいが、このような効果を得るためには、Ｂ含有量は０．０００１％以上であることが好ましい。Ｂ含有量は０．０００３％以上、０．０００５％以上又は０．０００７％以上であってもよい。一方で、Ｂを過度に含有すると、靭性及び／又は溶接性が低下する場合がある。したがって、Ｂ含有量は０．０２００％以下である。Ｂ含有量は０．０１００％以下、０．００５０％以下、０．００３０％以下又は０．００２０％以下であってもよい。 [B: 0 to 0.0200%]
Boron (B) is an element that contributes to the improvement of strength. The B content may be 0%, but in order to obtain such an effect, the B content is preferably 0.0001% or more. The B content may be 0.0003% or more, 0.0005% or more, or 0.0007% or more. On the other hand, if B is excessively contained, toughness and / or weldability may decrease. Therefore, the B content is 0.0200% or less. The B content may be 0.0100% or less, 0.0050% or less, 0.0030% or less, or 0.0020% or less.
［Ｃｏ：０～３．００％］
コバルト（Ｃｏ）は焼入れ性及び／又は耐熱性の向上に寄与する元素である。Ｃｏ含有量は０％であってもよいが、これらの効果を得るためには、Ｃｏ含有量は０．００１％以上であることが好ましい。Ｃｏ含有量は０．０１％以上、０．０２％以上、０．０５％以上、０．１０％以上又は０．５０％以上であってもよい。一方で、Ｃｏを過度に含有すると、熱間加工性が低下する場合があり、原料コストの増加にも繋がる。したがって、Ｃｏ含有量は３．００％以下である。Ｃｏ含有量は２．５０％以下、２．００％以下、１．５０％以下又は０．８０％以下であってもよい。 [Co: 0 to 3.00%]
Cobalt (Co) is an element that contributes to the improvement of hardenability and / or heat resistance. The Co content may be 0%, but in order to obtain these effects, the Co content is preferably 0.001% or more. The Co content may be 0.01% or more, 0.02% or more, 0.05% or more, 0.10% or more, or 0.50% or more. On the other hand, if Co is excessively contained, the hot workability may be lowered, which leads to an increase in raw material cost. Therefore, the Co content is 3.00% or less. The Co content may be 2.50% or less, 2.00% or less, 1.50% or less, or 0.80% or less.
コバルト（Ｃｏ）は焼入れ性及び／又は耐熱性の向上に寄与する元素である。Ｃｏ含有量は０％であってもよいが、これらの効果を得るためには、Ｃｏ含有量は０．００１％以上であることが好ましい。Ｃｏ含有量は０．０１％以上、０．０２％以上、０．０５％以上、０．１０％以上又は０．５０％以上であってもよい。一方で、Ｃｏを過度に含有すると、熱間加工性が低下する場合があり、原料コストの増加にも繋がる。したがって、Ｃｏ含有量は３．００％以下である。Ｃｏ含有量は２．５０％以下、２．００％以下、１．５０％以下又は０．８０％以下であってもよい。 [Co: 0 to 3.00%]
Cobalt (Co) is an element that contributes to the improvement of hardenability and / or heat resistance. The Co content may be 0%, but in order to obtain these effects, the Co content is preferably 0.001% or more. The Co content may be 0.01% or more, 0.02% or more, 0.05% or more, 0.10% or more, or 0.50% or more. On the other hand, if Co is excessively contained, the hot workability may be lowered, which leads to an increase in raw material cost. Therefore, the Co content is 3.00% or less. The Co content may be 2.50% or less, 2.00% or less, 1.50% or less, or 0.80% or less.
［Ｂｅ：０～０．０５０％］
ベリリウム（Ｂｅ）は、母材の強度の上昇及び組織の微細化に有効な元素である。Ｂｅ含有量は０％であってもよいが、このような効果を得るためには、Ｂｅ含有量は０．０００３％以上であることが好ましい。Ｂｅ含有量は０．０００５％以上、０．００１％以上又は０．０１０％以上であってもよい。一方で、Ｂｅを過度に含有すると、成形性が低下する場合がある。したがって、Ｂｅ含有量は０．０５０％以下である。Ｂｅ含有量は０．０４０％以下、０．０３０％以下又は０．０２０％以下であってもよい。 [Be: 0 to 0.050%]
Beryllium (Be) is an element effective for increasing the strength of the base metal and refining the structure. The Be content may be 0%, but in order to obtain such an effect, the Be content is preferably 0.0003% or more. The Be content may be 0.0005% or more, 0.001% or more, or 0.010% or more. On the other hand, if Be is excessively contained, the moldability may be deteriorated. Therefore, the Be content is 0.050% or less. The Be content may be 0.040% or less, 0.030% or less, or 0.020% or less.
ベリリウム（Ｂｅ）は、母材の強度の上昇及び組織の微細化に有効な元素である。Ｂｅ含有量は０％であってもよいが、このような効果を得るためには、Ｂｅ含有量は０．０００３％以上であることが好ましい。Ｂｅ含有量は０．０００５％以上、０．００１％以上又は０．０１０％以上であってもよい。一方で、Ｂｅを過度に含有すると、成形性が低下する場合がある。したがって、Ｂｅ含有量は０．０５０％以下である。Ｂｅ含有量は０．０４０％以下、０．０３０％以下又は０．０２０％以下であってもよい。 [Be: 0 to 0.050%]
Beryllium (Be) is an element effective for increasing the strength of the base metal and refining the structure. The Be content may be 0%, but in order to obtain such an effect, the Be content is preferably 0.0003% or more. The Be content may be 0.0005% or more, 0.001% or more, or 0.010% or more. On the other hand, if Be is excessively contained, the moldability may be deteriorated. Therefore, the Be content is 0.050% or less. The Be content may be 0.040% or less, 0.030% or less, or 0.020% or less.
［Ａｇ：０～０．５００％］
銀（Ａｇ）は、母材の強度の上昇及び組織の微細化に有効な元素である。Ａｇ含有量は０％であってもよいが、このような効果を得るためには、Ａｇ含有量は０．００１％以上であることが好ましい。Ａｇ含有量は０．０１０％以上、０．０２０％以上、０．０３０％以上又は０．０５０％以上であってもよい。一方で、Ａｇを過度に含有すると、成形性が低下する場合がある。したがって、Ａｇ含有量は０．５００％以下である。Ａｇ含有量は０．４００％以下、０．３００％以下又は０．２００％以下であってもよい。 [Ag: 0 to 0.500%]
Silver (Ag) is an element effective for increasing the strength of the base material and refining the structure. The Ag content may be 0%, but in order to obtain such an effect, the Ag content is preferably 0.001% or more. The Ag content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more. On the other hand, if Ag is excessively contained, the moldability may be deteriorated. Therefore, the Ag content is 0.500% or less. The Ag content may be 0.400% or less, 0.300% or less, or 0.200% or less.
銀（Ａｇ）は、母材の強度の上昇及び組織の微細化に有効な元素である。Ａｇ含有量は０％であってもよいが、このような効果を得るためには、Ａｇ含有量は０．００１％以上であることが好ましい。Ａｇ含有量は０．０１０％以上、０．０２０％以上、０．０３０％以上又は０．０５０％以上であってもよい。一方で、Ａｇを過度に含有すると、成形性が低下する場合がある。したがって、Ａｇ含有量は０．５００％以下である。Ａｇ含有量は０．４００％以下、０．３００％以下又は０．２００％以下であってもよい。 [Ag: 0 to 0.500%]
Silver (Ag) is an element effective for increasing the strength of the base material and refining the structure. The Ag content may be 0%, but in order to obtain such an effect, the Ag content is preferably 0.001% or more. The Ag content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more. On the other hand, if Ag is excessively contained, the moldability may be deteriorated. Therefore, the Ag content is 0.500% or less. The Ag content may be 0.400% or less, 0.300% or less, or 0.200% or less.
［Ｚｒ：０～０．５０００％］
ジルコニウム（Ｚｒ）は、硫化物の形態を制御できる元素である。Ｚｒ含有量は０％であってもよいが、このような効果を得るためには、Ｚｒ含有量は０．０００１％以上であることが好ましい。一方で、Ｚｒを過度に含有しても効果が飽和し、それゆえＺｒを必要以上に鋼材中に含有させることは製造コストの上昇を招く虞がある。したがって、Ｚｒ含有量は０．５０００％以下である。 [Zr: 0 to 0.5000%]
Zirconium (Zr) is an element that can control the morphology of sulfides. The Zr content may be 0%, but in order to obtain such an effect, the Zr content is preferably 0.0001% or more. On the other hand, even if Zr is excessively contained, the effect is saturated, and therefore, if Zr is contained in the steel material more than necessary, the manufacturing cost may increase. Therefore, the Zr content is 0.5000% or less.
ジルコニウム（Ｚｒ）は、硫化物の形態を制御できる元素である。Ｚｒ含有量は０％であってもよいが、このような効果を得るためには、Ｚｒ含有量は０．０００１％以上であることが好ましい。一方で、Ｚｒを過度に含有しても効果が飽和し、それゆえＺｒを必要以上に鋼材中に含有させることは製造コストの上昇を招く虞がある。したがって、Ｚｒ含有量は０．５０００％以下である。 [Zr: 0 to 0.5000%]
Zirconium (Zr) is an element that can control the morphology of sulfides. The Zr content may be 0%, but in order to obtain such an effect, the Zr content is preferably 0.0001% or more. On the other hand, even if Zr is excessively contained, the effect is saturated, and therefore, if Zr is contained in the steel material more than necessary, the manufacturing cost may increase. Therefore, the Zr content is 0.5000% or less.
［Ｈｆ：０～０．５０００％］
ハフニウム（Ｈｆ）は、硫化物の形態を制御できる元素である。Ｈｆ含有量は０％であってもよいが、このような効果を得るためには、Ｈｆ含有量は０．０００１％以上であることが好ましい。一方で、Ｈｆを過度に含有しても効果が飽和し、それゆえＨｆを必要以上に鋼材中に含有させることは製造コストの上昇を招く虞がある。したがって、Ｈｆ含有量は０．５０００％以下である。 [Hf: 0 to 0.5000%]
Hafnium (Hf) is an element that can control the morphology of sulfides. The Hf content may be 0%, but in order to obtain such an effect, the Hf content is preferably 0.0001% or more. On the other hand, even if Hf is excessively contained, the effect is saturated, and therefore, if Hf is contained in the steel material more than necessary, the manufacturing cost may increase. Therefore, the Hf content is 0.5000% or less.
ハフニウム（Ｈｆ）は、硫化物の形態を制御できる元素である。Ｈｆ含有量は０％であってもよいが、このような効果を得るためには、Ｈｆ含有量は０．０００１％以上であることが好ましい。一方で、Ｈｆを過度に含有しても効果が飽和し、それゆえＨｆを必要以上に鋼材中に含有させることは製造コストの上昇を招く虞がある。したがって、Ｈｆ含有量は０．５０００％以下である。 [Hf: 0 to 0.5000%]
Hafnium (Hf) is an element that can control the morphology of sulfides. The Hf content may be 0%, but in order to obtain such an effect, the Hf content is preferably 0.0001% or more. On the other hand, even if Hf is excessively contained, the effect is saturated, and therefore, if Hf is contained in the steel material more than necessary, the manufacturing cost may increase. Therefore, the Hf content is 0.5000% or less.
［Ｃａ：０～０．０５００％］
カルシウム（Ｃａ）は、硫化物の形態を制御できる元素である。Ｃａ含有量は０％であってもよいが、このような効果を得るためには、Ｃａ含有量は０．０００１％以上であることが好ましい。一方で、Ｃａを過度に含有しても効果が飽和し、それゆえＣａを必要以上に鋼材中に含有させることは製造コストの上昇を招く虞がある。したがって、Ｃａ含有量は０．０５００％以下である。 [Ca: 0-0.0500%]
Calcium (Ca) is an element that can control the morphology of sulfides. The Ca content may be 0%, but in order to obtain such an effect, the Ca content is preferably 0.0001% or more. On the other hand, even if Ca is excessively contained, the effect is saturated, and therefore, if Ca is contained in the steel material more than necessary, the manufacturing cost may increase. Therefore, the Ca content is 0.0500% or less.
カルシウム（Ｃａ）は、硫化物の形態を制御できる元素である。Ｃａ含有量は０％であってもよいが、このような効果を得るためには、Ｃａ含有量は０．０００１％以上であることが好ましい。一方で、Ｃａを過度に含有しても効果が飽和し、それゆえＣａを必要以上に鋼材中に含有させることは製造コストの上昇を招く虞がある。したがって、Ｃａ含有量は０．０５００％以下である。 [Ca: 0-0.0500%]
Calcium (Ca) is an element that can control the morphology of sulfides. The Ca content may be 0%, but in order to obtain such an effect, the Ca content is preferably 0.0001% or more. On the other hand, even if Ca is excessively contained, the effect is saturated, and therefore, if Ca is contained in the steel material more than necessary, the manufacturing cost may increase. Therefore, the Ca content is 0.0500% or less.
［Ｍｇ：０～０．０５００％］
マグネシウム（Ｍｇ）は、硫化物の形態を制御できる元素である。Ｍｇ含有量は０％であってもよいが、このような効果を得るためには、Ｍｇ含有量は０．０００１％以上であることが好ましい。Ｍｇ含有量は０．００１５％超、０．００１６％以上、０．００１８％以上又は０．００２０％以上であってもよい。一方で、Ｍｇを過度に含有しても効果が飽和し、粗大な介在物の形成に起因して冷間成形性及び／又は靭性が低下する場合がある。したがって、Ｍｇ含有量は０．０５００％以下である。Ｍｇ含有量は０．０４００％以下、０．０３００％以下又は０．０２００％以下であってもよい。 [Mg: 0 to 0.0500%]
Magnesium (Mg) is an element that can control the morphology of sulfides. The Mg content may be 0%, but in order to obtain such an effect, the Mg content is preferably 0.0001% or more. The Mg content may be greater than 0.0015%, greater than 0.0016%, greater than or equal to 0.0018% or greater than or equal to 0.0020%. On the other hand, even if Mg is excessively contained, the effect is saturated, and cold formability and / or toughness may decrease due to the formation of coarse inclusions. Therefore, the Mg content is 0.0500% or less. The Mg content may be 0.0400% or less, 0.0300% or less, or 0.0200% or less.
マグネシウム（Ｍｇ）は、硫化物の形態を制御できる元素である。Ｍｇ含有量は０％であってもよいが、このような効果を得るためには、Ｍｇ含有量は０．０００１％以上であることが好ましい。Ｍｇ含有量は０．００１５％超、０．００１６％以上、０．００１８％以上又は０．００２０％以上であってもよい。一方で、Ｍｇを過度に含有しても効果が飽和し、粗大な介在物の形成に起因して冷間成形性及び／又は靭性が低下する場合がある。したがって、Ｍｇ含有量は０．０５００％以下である。Ｍｇ含有量は０．０４００％以下、０．０３００％以下又は０．０２００％以下であってもよい。 [Mg: 0 to 0.0500%]
Magnesium (Mg) is an element that can control the morphology of sulfides. The Mg content may be 0%, but in order to obtain such an effect, the Mg content is preferably 0.0001% or more. The Mg content may be greater than 0.0015%, greater than 0.0016%, greater than or equal to 0.0018% or greater than or equal to 0.0020%. On the other hand, even if Mg is excessively contained, the effect is saturated, and cold formability and / or toughness may decrease due to the formation of coarse inclusions. Therefore, the Mg content is 0.0500% or less. The Mg content may be 0.0400% or less, 0.0300% or less, or 0.0200% or less.
［Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種：合計で０～０．５０００％］
ランタン（Ｌａ）、セリウム（Ｃｅ）、ネオジム（Ｎｄ）、プロメチウム（Ｐｍ）及びイットリウム（Ｙ）は、Ｃａ及びＭｇと同様に硫化物の形態を制御できる元素である。Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種の含有量の合計は０％であってもよいが、このような効果を得るためには０．０００１％以上であることが好ましい。Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種の含有量の合計は０．０００２％以上、０．０００３％以上又は０．０００４％以上であってもよい。一方で、これらの元素を過度に含有しても効果が飽和し、粗大な酸化物等が形成して冷間成形性が低下する場合がある。したがって、Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種の含有量の合計は０．５０００％以下であり、０．４０００％以下、０．３０００％以下又は０．２０００％以下であってもよい。 [At least one of La, Ce, Nd, Pm and Y: 0 to 0.5000% in total]
Lanthanum (La), cerium (Ce), neodymium (Nd), promethium (Pm) and yttrium (Y) are elements that can control the morphology of sulfides, similar to Ca and Mg. The total content of at least one of La, Ce, Nd, Pm and Y may be 0%, but is preferably 0.0001% or more in order to obtain such an effect. The total content of at least one of La, Ce, Nd, Pm and Y may be 0.0002% or more, 0.0003% or more or 0.0004% or more. On the other hand, even if these elements are excessively contained, the effect may be saturated and coarse oxides or the like may be formed to reduce the cold formability. Therefore, the total content of at least one of La, Ce, Nd, Pm and Y is 0.5000% or less, even if it is 0.4000% or less, 0.3000% or less or 0.2000% or less. good.
ランタン（Ｌａ）、セリウム（Ｃｅ）、ネオジム（Ｎｄ）、プロメチウム（Ｐｍ）及びイットリウム（Ｙ）は、Ｃａ及びＭｇと同様に硫化物の形態を制御できる元素である。Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種の含有量の合計は０％であってもよいが、このような効果を得るためには０．０００１％以上であることが好ましい。Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種の含有量の合計は０．０００２％以上、０．０００３％以上又は０．０００４％以上であってもよい。一方で、これらの元素を過度に含有しても効果が飽和し、粗大な酸化物等が形成して冷間成形性が低下する場合がある。したがって、Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種の含有量の合計は０．５０００％以下であり、０．４０００％以下、０．３０００％以下又は０．２０００％以下であってもよい。 [At least one of La, Ce, Nd, Pm and Y: 0 to 0.5000% in total]
Lanthanum (La), cerium (Ce), neodymium (Nd), promethium (Pm) and yttrium (Y) are elements that can control the morphology of sulfides, similar to Ca and Mg. The total content of at least one of La, Ce, Nd, Pm and Y may be 0%, but is preferably 0.0001% or more in order to obtain such an effect. The total content of at least one of La, Ce, Nd, Pm and Y may be 0.0002% or more, 0.0003% or more or 0.0004% or more. On the other hand, even if these elements are excessively contained, the effect may be saturated and coarse oxides or the like may be formed to reduce the cold formability. Therefore, the total content of at least one of La, Ce, Nd, Pm and Y is 0.5000% or less, even if it is 0.4000% or less, 0.3000% or less or 0.2000% or less. good.
［Ｓｎ：０～０．３００％］
錫（Ｓｎ）は耐食性の向上に有効な元素である。Ｓｎ含有量は０％であってもよいが、このような効果を得るためには、Ｓｎ含有量は０．００１％以上であることが好ましい。Ｓｎ含有量は０．０１０％以上、０．０２０％以上、０．０３０％以上又は０．０５０％以上であってもよい。一方で、Ｓｎを過度に含有すると、靭性、特には低温靭性の低下を招く場合がある。したがって、Ｓｎ含有量は０．３００％以下である。Ｓｎ含有量は０．２５０％以下、０．２００％以下又は０．１５０％以下であってもよい。 [Sn: 0 to 0.300%]
Tin (Sn) is an element effective for improving corrosion resistance. The Sn content may be 0%, but in order to obtain such an effect, the Sn content is preferably 0.001% or more. The Sn content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more. On the other hand, excessive inclusion of Sn may lead to a decrease in toughness, particularly low temperature toughness. Therefore, the Sn content is 0.300% or less. The Sn content may be 0.250% or less, 0.200% or less, or 0.150% or less.
錫（Ｓｎ）は耐食性の向上に有効な元素である。Ｓｎ含有量は０％であってもよいが、このような効果を得るためには、Ｓｎ含有量は０．００１％以上であることが好ましい。Ｓｎ含有量は０．０１０％以上、０．０２０％以上、０．０３０％以上又は０．０５０％以上であってもよい。一方で、Ｓｎを過度に含有すると、靭性、特には低温靭性の低下を招く場合がある。したがって、Ｓｎ含有量は０．３００％以下である。Ｓｎ含有量は０．２５０％以下、０．２００％以下又は０．１５０％以下であってもよい。 [Sn: 0 to 0.300%]
Tin (Sn) is an element effective for improving corrosion resistance. The Sn content may be 0%, but in order to obtain such an effect, the Sn content is preferably 0.001% or more. The Sn content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more. On the other hand, excessive inclusion of Sn may lead to a decrease in toughness, particularly low temperature toughness. Therefore, the Sn content is 0.300% or less. The Sn content may be 0.250% or less, 0.200% or less, or 0.150% or less.
［Ｓｂ：０～０．３００％］
アンチモン（Ｓｂ）は、Ｓｎと同様に耐食性の向上に有効な元素であり、特にＳｎと複合して含有させることにより効果を増大させることができる。Ｓｂ含有量は０％であってもよいが、耐食性向上の効果を得るためには、Ｓｂ含有量は０．００１％以上であることが好ましい。Ｓｂ含有量は０．０１０％以上、０．０２０％以上、０．０３０％以上又は０．０５０％以上であってもよい。一方で、Ｓｂを過度に含有すると、靭性、特には低温靭性の低下を招く場合がある。したがって、Ｓｂ含有量は０．３００％以下である。Ｓｂ含有量は０．２５０％以下、０．２００％以下又は０．１５０％以下であってもよい。 [Sb: 0 to 0.300%]
Antimony (Sb) is an element effective for improving corrosion resistance like Sn, and the effect can be increased by including it in combination with Sn. The Sb content may be 0%, but in order to obtain the effect of improving the corrosion resistance, the Sb content is preferably 0.001% or more. The Sb content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more. On the other hand, excessive content of Sb may lead to a decrease in toughness, particularly low temperature toughness. Therefore, the Sb content is 0.300% or less. The Sb content may be 0.250% or less, 0.200% or less, or 0.150% or less.
アンチモン（Ｓｂ）は、Ｓｎと同様に耐食性の向上に有効な元素であり、特にＳｎと複合して含有させることにより効果を増大させることができる。Ｓｂ含有量は０％であってもよいが、耐食性向上の効果を得るためには、Ｓｂ含有量は０．００１％以上であることが好ましい。Ｓｂ含有量は０．０１０％以上、０．０２０％以上、０．０３０％以上又は０．０５０％以上であってもよい。一方で、Ｓｂを過度に含有すると、靭性、特には低温靭性の低下を招く場合がある。したがって、Ｓｂ含有量は０．３００％以下である。Ｓｂ含有量は０．２５０％以下、０．２００％以下又は０．１５０％以下であってもよい。 [Sb: 0 to 0.300%]
Antimony (Sb) is an element effective for improving corrosion resistance like Sn, and the effect can be increased by including it in combination with Sn. The Sb content may be 0%, but in order to obtain the effect of improving the corrosion resistance, the Sb content is preferably 0.001% or more. The Sb content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more. On the other hand, excessive content of Sb may lead to a decrease in toughness, particularly low temperature toughness. Therefore, the Sb content is 0.300% or less. The Sb content may be 0.250% or less, 0.200% or less, or 0.150% or less.
［Ｔｅ：０～０．１００％］
テルル（Ｔｅ）は、ＭｎやＳなどと低融点化合物を形成して潤滑効果を高めるため、鋼の被削性を改善するのに有効な元素である。Ｔｅ含有量は０％であってもよいが、このような効果を得るためには、Ｔｅ含有量は０．００１％以上であることが好ましい。Ｔｅ含有量は０．０１０％以上、０．０２０％以上、０．０３０％以上又は０．０４０％以上であってもよい。一方で、Ｔｅを過度に含有しても効果が飽和し、合金コストの増加を招く。したがって、Ｔｅ含有量は０．１００％以下である。Ｔｅ含有量は０．０９０％以下、０．０８０％以下又は０．０７０％以下であってもよい。 [Te: 0 to 0.100%]
Tellurium (Te) is an element effective for improving the machinability of steel because it forms a low melting point compound with Mn, S and the like to enhance the lubricating effect. The Te content may be 0%, but in order to obtain such an effect, the Te content is preferably 0.001% or more. The Te content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.040% or more. On the other hand, even if Te is excessively contained, the effect is saturated and the alloy cost increases. Therefore, the Te content is 0.100% or less. The Te content may be 0.090% or less, 0.080% or less, or 0.070% or less.
テルル（Ｔｅ）は、ＭｎやＳなどと低融点化合物を形成して潤滑効果を高めるため、鋼の被削性を改善するのに有効な元素である。Ｔｅ含有量は０％であってもよいが、このような効果を得るためには、Ｔｅ含有量は０．００１％以上であることが好ましい。Ｔｅ含有量は０．０１０％以上、０．０２０％以上、０．０３０％以上又は０．０４０％以上であってもよい。一方で、Ｔｅを過度に含有しても効果が飽和し、合金コストの増加を招く。したがって、Ｔｅ含有量は０．１００％以下である。Ｔｅ含有量は０．０９０％以下、０．０８０％以下又は０．０７０％以下であってもよい。 [Te: 0 to 0.100%]
Tellurium (Te) is an element effective for improving the machinability of steel because it forms a low melting point compound with Mn, S and the like to enhance the lubricating effect. The Te content may be 0%, but in order to obtain such an effect, the Te content is preferably 0.001% or more. The Te content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.040% or more. On the other hand, even if Te is excessively contained, the effect is saturated and the alloy cost increases. Therefore, the Te content is 0.100% or less. The Te content may be 0.090% or less, 0.080% or less, or 0.070% or less.
［Ｓｅ：０～０．１００％］
セレン（Ｓｅ）は、鋼中に生成するセレン化物が被削材のせん断塑性変形に変化を与え、切りくずが破砕されやすくなるため、鋼の被削性を改善するのに有効な元素である。Ｓｅ含有量は０％であってもよいが、このような効果を得るためには、Ｓｅ含有量は０．００１％以上であることが好ましい。Ｓｅ含有量は０．０１０％以上、０．０２０％以上、０．０３０％以上又は０．０４０％以上であってもよい。一方で、Ｓｅを過度に含有しても効果が飽和し、合金コストの増加を招く。したがって、Ｓｅ含有量は０．１００％以下である。Ｓｅ含有量は０．０９０％以下、０．０８０％以下又は０．０７０％以下であってもよい。 [Se: 0 to 0.100%]
Selenium (Se) is an effective element for improving the machinability of steel because the selenium produced in the steel changes the shear-plastic deformation of the work material and the chips are easily crushed. .. The Se content may be 0%, but in order to obtain such an effect, the Se content is preferably 0.001% or more. The Se content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.040% or more. On the other hand, even if Se is excessively contained, the effect is saturated and the alloy cost increases. Therefore, the Se content is 0.100% or less. The Se content may be 0.090% or less, 0.080% or less, or 0.070% or less.
セレン（Ｓｅ）は、鋼中に生成するセレン化物が被削材のせん断塑性変形に変化を与え、切りくずが破砕されやすくなるため、鋼の被削性を改善するのに有効な元素である。Ｓｅ含有量は０％であってもよいが、このような効果を得るためには、Ｓｅ含有量は０．００１％以上であることが好ましい。Ｓｅ含有量は０．０１０％以上、０．０２０％以上、０．０３０％以上又は０．０４０％以上であってもよい。一方で、Ｓｅを過度に含有しても効果が飽和し、合金コストの増加を招く。したがって、Ｓｅ含有量は０．１００％以下である。Ｓｅ含有量は０．０９０％以下、０．０８０％以下又は０．０７０％以下であってもよい。 [Se: 0 to 0.100%]
Selenium (Se) is an effective element for improving the machinability of steel because the selenium produced in the steel changes the shear-plastic deformation of the work material and the chips are easily crushed. .. The Se content may be 0%, but in order to obtain such an effect, the Se content is preferably 0.001% or more. The Se content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.040% or more. On the other hand, even if Se is excessively contained, the effect is saturated and the alloy cost increases. Therefore, the Se content is 0.100% or less. The Se content may be 0.090% or less, 0.080% or less, or 0.070% or less.
［Ａｓ：０～０．０５０％］
ヒ素（Ａｓ）は、鋼の被削性を改善するのに有効な元素である。Ａｓ含有量は０％であってもよいが、このような効果を得るためには、Ａｓ含有量は０．００１％以上であることが好ましい。Ａｓ含有量は０．００５％以上又は０．０１０％以上であってもよい。一方で、Ａｓを過度に含有すると、熱間加工性が低下する場合がある。したがって、Ａｓ含有量は０．０５０％以下である。Ａｓ含有量は０．０４０％以下、０．０３０％以下又は０．０２０％以下であってもよい。 [As: 0 to 0.050%]
Arsenic (As) is an element effective in improving the machinability of steel. The As content may be 0%, but in order to obtain such an effect, the As content is preferably 0.001% or more. The As content may be 0.005% or more or 0.010% or more. On the other hand, if As is excessively contained, the hot workability may be deteriorated. Therefore, the As content is 0.050% or less. The As content may be 0.040% or less, 0.030% or less, or 0.020% or less.
ヒ素（Ａｓ）は、鋼の被削性を改善するのに有効な元素である。Ａｓ含有量は０％であってもよいが、このような効果を得るためには、Ａｓ含有量は０．００１％以上であることが好ましい。Ａｓ含有量は０．００５％以上又は０．０１０％以上であってもよい。一方で、Ａｓを過度に含有すると、熱間加工性が低下する場合がある。したがって、Ａｓ含有量は０．０５０％以下である。Ａｓ含有量は０．０４０％以下、０．０３０％以下又は０．０２０％以下であってもよい。 [As: 0 to 0.050%]
Arsenic (As) is an element effective in improving the machinability of steel. The As content may be 0%, but in order to obtain such an effect, the As content is preferably 0.001% or more. The As content may be 0.005% or more or 0.010% or more. On the other hand, if As is excessively contained, the hot workability may be deteriorated. Therefore, the As content is 0.050% or less. The As content may be 0.040% or less, 0.030% or less, or 0.020% or less.
［Ｂｉ：０～０．５００％］
ビスマス（Ｂｉ）は、鋼の被削性を改善するのに有効な元素である。Ｂｉ含有量は０％であってもよいが、このような効果を得るためには、Ｂｉ含有量は０．００１％以上であることが好ましい。Ｂｉ含有量は０．０１０％以上、０．０２０％以上、０．０３０％以上又は０．０５０％以上であってもよい。一方で、Ｂｉを過度に含有しても効果が飽和し、合金コストの増加を招く。したがって、Ｂｉ含有量は０．５００％以下である。Ｂｉ含有量は０．４００％以下、０．３００％以下又は０．２００％以下であってもよい。 [Bi: 0 to 0.500%]
Bismuth (Bi) is an element effective in improving the machinability of steel. The Bi content may be 0%, but in order to obtain such an effect, the Bi content is preferably 0.001% or more. The Bi content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more. On the other hand, even if Bi is excessively contained, the effect is saturated and the alloy cost increases. Therefore, the Bi content is 0.500% or less. The Bi content may be 0.400% or less, 0.300% or less, or 0.200% or less.
ビスマス（Ｂｉ）は、鋼の被削性を改善するのに有効な元素である。Ｂｉ含有量は０％であってもよいが、このような効果を得るためには、Ｂｉ含有量は０．００１％以上であることが好ましい。Ｂｉ含有量は０．０１０％以上、０．０２０％以上、０．０３０％以上又は０．０５０％以上であってもよい。一方で、Ｂｉを過度に含有しても効果が飽和し、合金コストの増加を招く。したがって、Ｂｉ含有量は０．５００％以下である。Ｂｉ含有量は０．４００％以下、０．３００％以下又は０．２００％以下であってもよい。 [Bi: 0 to 0.500%]
Bismuth (Bi) is an element effective in improving the machinability of steel. The Bi content may be 0%, but in order to obtain such an effect, the Bi content is preferably 0.001% or more. The Bi content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more. On the other hand, even if Bi is excessively contained, the effect is saturated and the alloy cost increases. Therefore, the Bi content is 0.500% or less. The Bi content may be 0.400% or less, 0.300% or less, or 0.200% or less.
［Ｐｂ：０～０．５００％］
鉛（Ｐｂ）は、切削による温度上昇で溶融してクラックの進展を促進するため、鋼の被削性を改善するのに有効な元素である。Ｐｂ含有量は０％であってもよいが、このような効果を得るためには、Ｐｂ含有量は０．００１％以上であることが好ましい。Ｐｂ含有量は０．０１０％以上、０．０２０％以上、０．０３０％以上又は０．０５０％以上であってもよい。一方で、Ｐｂを過度に含有すると、熱間加工性が低下する場合がある。したがって、Ｐｂ含有量は０．５００％以下である。Ｐｂ含有量は０．４００％以下、０．３００％以下又は０．２００％以下であってもよい。 [Pb: 0 to 0.500%]
Lead (Pb) is an element effective for improving the machinability of steel because it melts when the temperature rises due to cutting and promotes the growth of cracks. The Pb content may be 0%, but in order to obtain such an effect, the Pb content is preferably 0.001% or more. The Pb content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more. On the other hand, if Pb is excessively contained, the hot workability may be deteriorated. Therefore, the Pb content is 0.500% or less. The Pb content may be 0.400% or less, 0.300% or less, or 0.200% or less.
鉛（Ｐｂ）は、切削による温度上昇で溶融してクラックの進展を促進するため、鋼の被削性を改善するのに有効な元素である。Ｐｂ含有量は０％であってもよいが、このような効果を得るためには、Ｐｂ含有量は０．００１％以上であることが好ましい。Ｐｂ含有量は０．０１０％以上、０．０２０％以上、０．０３０％以上又は０．０５０％以上であってもよい。一方で、Ｐｂを過度に含有すると、熱間加工性が低下する場合がある。したがって、Ｐｂ含有量は０．５００％以下である。Ｐｂ含有量は０．４００％以下、０．３００％以下又は０．２００％以下であってもよい。 [Pb: 0 to 0.500%]
Lead (Pb) is an element effective for improving the machinability of steel because it melts when the temperature rises due to cutting and promotes the growth of cracks. The Pb content may be 0%, but in order to obtain such an effect, the Pb content is preferably 0.001% or more. The Pb content may be 0.010% or more, 0.020% or more, 0.030% or more, or 0.050% or more. On the other hand, if Pb is excessively contained, the hot workability may be deteriorated. Therefore, the Pb content is 0.500% or less. The Pb content may be 0.400% or less, 0.300% or less, or 0.200% or less.
本発明の実施形態に係る鋼材において、上記の元素以外の残部は、Ｆｅ及び不純物からなる。不純物とは、鋼材を工業的に製造する際に、鉱石やスクラップ等のような原料を始めとして、製造工程の種々の要因によって混入する成分等である。
In the steel material according to the embodiment of the present invention, the balance other than the above elements consists of Fe and impurities. Impurities are components that are mixed in by various factors in the manufacturing process, including raw materials such as ore and scrap, when steel materials are industrially manufactured.
［Ｘ元素の有効量］
本発明の実施形態によれば、Ｐｒ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ、及びＳｃからなるＸ元素の有効量は、下記式１の左辺によって求められ、そしてその値は下記式１を満たすようにする。
０．４０［Ｐｒ］＋０．３７［Ｓｍ］＋０．３７［Ｅｕ］＋０．３６［Ｇｄ］＋０．３５［Ｔｂ］＋０．３４［Ｄｙ］＋０．３４［Ｈｏ］＋０．３３［Ｅｒ］＋０．３３［Ｔｍ］＋０．３２［Ｙｂ］＋０．３２［Ｌｕ］＋１．２４［Ｓｃ］－２．３３［Ｏ］－３．９９［Ｎ］－１．７４［Ｓ］ ≧ ０．０００３ ・・・式１
ここで、［Ｐｒ］、［Ｓｍ］、［Ｅｕ］、［Ｇｄ］、［Ｔｂ］、［Ｄｙ］、［Ｈｏ］、［Ｅｒ］、［Ｔｍ］、［Ｙｂ］、［Ｌｕ］、［Ｓｃ］、［Ｏ］、［Ｎ］、及び［Ｓ］は、各元素の含有量［質量％］であり、元素を含有しない場合は０である。 [Effective amount of element X]
According to the embodiment of the present invention, the effective amount of the X element consisting of Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc can be determined by the left side of the followingformula 1. , And its value shall satisfy the following equation 1.
0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] +0. 33 [Tm] +0.32 [Yb] +0.32 [Lu] +1.24 [Sc] -2.33 [O] -3.99 [N] -1.74 [S] ≧ 0.0003 ...Equation 1
Here, [Pr], [Sm], [Eu], [Gd], [Tb], [Dy], [Ho], [Er], [Tm], [Yb], [Lu], [Sc]. , [O], [N], and [S] are the content [mass%] of each element, and are 0 when the element is not contained.
本発明の実施形態によれば、Ｐｒ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ、及びＳｃからなるＸ元素の有効量は、下記式１の左辺によって求められ、そしてその値は下記式１を満たすようにする。
０．４０［Ｐｒ］＋０．３７［Ｓｍ］＋０．３７［Ｅｕ］＋０．３６［Ｇｄ］＋０．３５［Ｔｂ］＋０．３４［Ｄｙ］＋０．３４［Ｈｏ］＋０．３３［Ｅｒ］＋０．３３［Ｔｍ］＋０．３２［Ｙｂ］＋０．３２［Ｌｕ］＋１．２４［Ｓｃ］－２．３３［Ｏ］－３．９９［Ｎ］－１．７４［Ｓ］ ≧ ０．０００３ ・・・式１
ここで、［Ｐｒ］、［Ｓｍ］、［Ｅｕ］、［Ｇｄ］、［Ｔｂ］、［Ｄｙ］、［Ｈｏ］、［Ｅｒ］、［Ｔｍ］、［Ｙｂ］、［Ｌｕ］、［Ｓｃ］、［Ｏ］、［Ｎ］、及び［Ｓ］は、各元素の含有量［質量％］であり、元素を含有しない場合は０である。 [Effective amount of element X]
According to the embodiment of the present invention, the effective amount of the X element consisting of Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc can be determined by the left side of the following
0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] +0. 33 [Tm] +0.32 [Yb] +0.32 [Lu] +1.24 [Sc] -2.33 [O] -3.99 [N] -1.74 [S] ≧ 0.0003 ...
Here, [Pr], [Sm], [Eu], [Gd], [Tb], [Dy], [Ho], [Er], [Tm], [Yb], [Lu], [Sc]. , [O], [N], and [S] are the content [mass%] of each element, and are 0 when the element is not contained.
上記Ｘ元素の有効量を上記式１を満たすようにすることで、オーステナイト中に存在しているＸ元素と鋼中のＰを反応させてリン化物を形成することができ、このようなリン化物の形成に起因して金属組織の粒成長を抑制することが可能となる。より詳しく説明すると、これらのＸ元素（以下、単に「Ｘ」ともいう）は、鋼中に存在するＯ（酸素）、Ｎ（窒素）及びＳ（硫黄）と結びついて、酸化物（Ｘ2Ｏ3）、窒化物（ＸＮ）及び硫化物（ＸＳ）からなる介在物を形成する傾向がある。当該介在物を形成してしまうと、少なくともこれらの介在物中のＸ元素はＰとの反応に寄与することはできない。したがって、Ｐとの反応を促進してピン止め粒子であるリン化物を形成するためには、介在物を形成せずにオーステナイト中でリン化物を形成し得るＸ元素の量を増加させる必要がある。
By making the effective amount of the X element satisfy the above formula 1, it is possible to react the X element existing in austenite with P in the steel to form a phosphide, and such a phosphide can be formed. It is possible to suppress the grain growth of the metal structure due to the formation of the metal structure. More specifically, these X elements (hereinafter, also simply referred to as “X”) are combined with O (oxygen), N (nitrogen) and S (sulfur) present in the steel to form an oxide (X 2 O). 3 ), tend to form inclusions consisting of nitrides (XN) and sulfides (XS). Once the inclusions are formed, at least the X element in these inclusions cannot contribute to the reaction with P. Therefore, in order to promote the reaction with P and form a phosphide, which is a pinning particle, it is necessary to increase the amount of element X that can form a phosphide in austenite without forming inclusions. ..
ここで、リン化物を形成し得るＸ元素の量は、鋼中に含まれるＸ元素の量から介在物（酸化物、窒化物及び硫化物）を形成するのに消費され得る最大量を差し引くことによって概算することが可能である。そこで、本発明の実施形態においては、このようにして概算されるリン化物を形成するのに有効なＸ元素の量（すなわち「Ｘ元素の有効量」）は、具体的には下記式Ａによって定義される。
Ｘの有効量［原子％］＝Σ（Ｍ[Fe]／Ｍ[X]）×［Ｘ］－（Ｍ[Fe]／Ｍ[O]）×［Ｏ］×２／３－（Ｍ[Fe]／Ｍ[N]）×［Ｎ］－（Ｍ[Fe]／Ｍ[S]）×［Ｓ］ ・・・式Ａ
ここで、ＸはＰｒ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ、及びＳｃの各Ｘ元素を表し、Ｍ[X]はＸ元素の原子量、Ｍ[Fe]はＦｅの原子量、Ｍ[O]はＯの原子量、Ｍ[N]はＮの原子量、Ｍ[S]はＳの原子量を表し、［Ｘ］、［Ｏ］、［Ｎ］及び［Ｓ］は、それぞれ対応する元素の含有量［質量％］であり、元素を含有しない場合は０である。 Here, the amount of element X that can form a phosphide is the amount of element X contained in the steel minus the maximum amount that can be consumed to form inclusions (oxides, nitrides and sulfides). It is possible to estimate by. Therefore, in the embodiment of the present invention, the amount of X element effective for forming the phosphide estimated in this way (that is, "effective amount of X element") is specifically determined by the following formula A. Defined.
Effective amount of X [atomic%] = Σ (M [Fe] / M [X] ) × [X]-(M [Fe] / M [O] ) × [O] × 2 / 3- (M [Fe ] ] / M [N] ) x [N]-(M [Fe] / M [S] ) x [S] ... Equation A
Here, X represents each X element of Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc, and M [X] is the atomic weight of the X element, M [Fe]. Is the atomic weight of Fe, M [O] is the atomic weight of O, M [N] is the atomic weight of N, M [S] is the atomic weight of S, and [X], [O], [N] and [S] are. , Each is the content [mass%] of the corresponding element, and is 0 when the element is not contained.
Ｘの有効量［原子％］＝Σ（Ｍ[Fe]／Ｍ[X]）×［Ｘ］－（Ｍ[Fe]／Ｍ[O]）×［Ｏ］×２／３－（Ｍ[Fe]／Ｍ[N]）×［Ｎ］－（Ｍ[Fe]／Ｍ[S]）×［Ｓ］ ・・・式Ａ
ここで、ＸはＰｒ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ、及びＳｃの各Ｘ元素を表し、Ｍ[X]はＸ元素の原子量、Ｍ[Fe]はＦｅの原子量、Ｍ[O]はＯの原子量、Ｍ[N]はＮの原子量、Ｍ[S]はＳの原子量を表し、［Ｘ］、［Ｏ］、［Ｎ］及び［Ｓ］は、それぞれ対応する元素の含有量［質量％］であり、元素を含有しない場合は０である。 Here, the amount of element X that can form a phosphide is the amount of element X contained in the steel minus the maximum amount that can be consumed to form inclusions (oxides, nitrides and sulfides). It is possible to estimate by. Therefore, in the embodiment of the present invention, the amount of X element effective for forming the phosphide estimated in this way (that is, "effective amount of X element") is specifically determined by the following formula A. Defined.
Effective amount of X [atomic%] = Σ (M [Fe] / M [X] ) × [X]-(M [Fe] / M [O] ) × [O] × 2 / 3- (M [Fe ] ] / M [N] ) x [N]-(M [Fe] / M [S] ) x [S] ... Equation A
Here, X represents each X element of Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc, and M [X] is the atomic weight of the X element, M [Fe]. Is the atomic weight of Fe, M [O] is the atomic weight of O, M [N] is the atomic weight of N, M [S] is the atomic weight of S, and [X], [O], [N] and [S] are. , Each is the content [mass%] of the corresponding element, and is 0 when the element is not contained.
上記式Ａについて以下に詳しく説明すると、まず、本発明の実施形態に係る鋼材には種々の合金元素が含有されているものの、鋼材全体としてはほぼＦｅによって構成されているか、あるいは任意選択元素であるＮｉ及び／又はＣｒを比較的多く含む場合（それぞれの最大含有量は６０．００％及び３０．００％）には、Ｆｅに加えてＮｉ及び／又はＣｒによってほぼ構成されていることが明らかである。一方で、Ｎｉ及びＣｒの原子量はＦｅの原子量と同等であることが周知である。このため、たとえ鋼材がＮｉ及び／又はＣｒを比較的多く含む場合であっても、Ｐｒ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ、及びＳｃの各Ｘ元素の原子％は、近似的には各Ｘ元素の含有量［質量％］にＦｅの原子量と当該各Ｘ元素の原子量の比を掛け算すること、すなわち（Ｍ[Fe]／Ｍ[X]）×［Ｘ］によって算出することができる。したがって、（Ｍ[Fe]／Ｍ[X]）×［Ｘ］によって算出される各Ｘ元素の量を合計することで（すなわちΣ（Ｍ[Fe]／Ｍ[X]）×［Ｘ］を計算することで）、Ｘ元素全体の原子％を算出することができる。
The above formula A will be described in detail below. First, although the steel material according to the embodiment of the present invention contains various alloying elements, the steel material as a whole is almost composed of Fe or is an optional element. When a certain Ni and / or Cr is contained in a relatively large amount (the maximum contents are 60.00% and 30.00%, respectively), it is clear that it is almost composed of Ni and / or Cr in addition to Fe. Is. On the other hand, it is well known that the atomic weights of Ni and Cr are equivalent to the atomic weights of Fe. Therefore, even if the steel material contains a relatively large amount of Ni and / or Cr, each X element of Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc. Approximately, the atomic% of is obtained by multiplying the content [mass%] of each X element by the ratio of the atomic weight of Fe to the atomic weight of each X element, that is, (M [Fe] / M [X] ) ×. It can be calculated by [X]. Therefore, by summing up the amounts of each X element calculated by (M [ Fe ] / M [X ] ) × [X] (that is, Σ (M [Fe] / M [X] ) × [X]. By calculation), the atomic% of the entire X element can be calculated.
次に、Ｘ元素全体の原子％のうち、酸化物（Ｘ2Ｏ3）、窒化物（ＸＮ）及び硫化物（ＸＳ）を形成するのに消費され得る最大量（原子％）を差し引くことで、リン化物を形成するのに有効に作用し得る鋼中のＸ元素の量を算出することができる。ここで、酸化物（Ｘ2Ｏ3）、窒化物（ＸＮ）及び硫化物（ＸＳ）を形成するのに消費され得るＸ元素の最大量（原子％）は、上で説明したのと同様の理由から近似的には鋼中のＦｅ、Ｏ、Ｎ及びＳの原子量並びにＯ、Ｎ及びＳの含有量を用いて、それぞれ（Ｍ[Fe]／Ｍ[O]）×［Ｏ］×２／３、（Ｍ[Fe]／Ｍ[N]）×［Ｎ］、及び（Ｍ[Fe]／Ｍ[S]）×［Ｓ］として算出することが可能である。したがって、リン化物を形成するためのＸ元素の有効量は、下記式Ａによって定義することができる。
Ｘの有効量［原子％］＝Σ（Ｍ[Fe]／Ｍ[X]）×［Ｘ］－（Ｍ[Fe]／Ｍ[O]）×［Ｏ］×２／３－（Ｍ[Fe]／Ｍ[N]）×［Ｎ］－（Ｍ[Fe]／Ｍ[S]）×［Ｓ］ ・・・式Ａ Next, by subtracting the maximum amount (atomic%) that can be consumed to form oxides (X 2 O 3 ), nitrides (XN) and sulfides (XS) from the atomic% of the total element X. , The amount of element X in steel that can effectively act to form phosphide can be calculated. Here, the maximum amount (atomic%) of element X that can be consumed to form oxides (X 2 O 3 ), nitrides (XN) and sulfides (XS) is the same as described above. Approximately for the reason, using the atomic weights of Fe, O, N and S and the contents of O, N and S in the steel, (M [Fe] / M [O] ) × [O] × 2 /, respectively. 3. It can be calculated as (M [Fe] / M [N] ) × [N] and (M [Fe] / M [S] ) × [S]. Therefore, the effective amount of element X for forming a phosphide can be defined by the following formula A.
Effective amount of X [atomic%] = Σ (M [Fe] / M [X] ) × [X]-(M [Fe] / M [O] ) × [O] × 2 / 3- (M [Fe ] ] / M [N] ) x [N]-(M [Fe] / M [S] ) x [S] ... Equation A
Ｘの有効量［原子％］＝Σ（Ｍ[Fe]／Ｍ[X]）×［Ｘ］－（Ｍ[Fe]／Ｍ[O]）×［Ｏ］×２／３－（Ｍ[Fe]／Ｍ[N]）×［Ｎ］－（Ｍ[Fe]／Ｍ[S]）×［Ｓ］ ・・・式Ａ Next, by subtracting the maximum amount (atomic%) that can be consumed to form oxides (X 2 O 3 ), nitrides (XN) and sulfides (XS) from the atomic% of the total element X. , The amount of element X in steel that can effectively act to form phosphide can be calculated. Here, the maximum amount (atomic%) of element X that can be consumed to form oxides (X 2 O 3 ), nitrides (XN) and sulfides (XS) is the same as described above. Approximately for the reason, using the atomic weights of Fe, O, N and S and the contents of O, N and S in the steel, (M [Fe] / M [O] ) × [O] × 2 /, respectively. 3. It can be calculated as (M [Fe] / M [N] ) × [N] and (M [Fe] / M [S] ) × [S]. Therefore, the effective amount of element X for forming a phosphide can be defined by the following formula A.
Effective amount of X [atomic%] = Σ (M [Fe] / M [X] ) × [X]-(M [Fe] / M [O] ) × [O] × 2 / 3- (M [Fe ] ] / M [N] ) x [N]-(M [Fe] / M [S] ) x [S] ... Equation A
ここで、Ｆｅ、Ｏ、Ｎ及びＳ並びに各Ｘ元素の原子量は、それぞれＦｅ：５５．８４５、Ｏ：１５．９９９４、Ｎ：１４．００６９、Ｓ：３２．０６８、Ｐｒ：１４０．９０８、Ｓｍ：１５０．３６、Ｅｕ：１５１．９６４、Ｇｄ：１５７．２５、Ｔｂ：１５８．９２５、Ｄｙ：１６２．５００、Ｈｏ：１６４．９３０、Ｅｒ：１６７．２５９、Ｔｍ：１６８．９３４、Ｙｂ：１７３．０４５、Ｌｕ：１７４．９６７、Ｓｃ：４４．９５５９である。したがって、上記式Ａに各元素の原子量を代入して整理すると、Ｘ元素の原子％による有効量は近似的には下記式Ｂによって表すことが可能となる。
有効量＝０．４０［Ｐｒ］＋０．３７［Ｓｍ］＋０．３７［Ｅｕ］＋０．３６［Ｇｄ］＋０．３５［Ｔｂ］＋０．３４［Ｄｙ］＋０．３４［Ｈｏ］＋０．３３［Ｅｒ］＋０．３３［Ｔｍ］＋０．３２［Ｙｂ］＋０．３２［Ｌｕ］＋１．２４［Ｓｃ］－２．３３［Ｏ］－３．９９［Ｎ］－１．７４［Ｓ］ ・・・式Ｂ
ここで、［Ｐｒ］、［Ｓｍ］、［Ｅｕ］、［Ｇｄ］、［Ｔｂ］、［Ｄｙ］、［Ｈｏ］、［Ｅｒ］、［Ｔｍ］、［Ｙｂ］、［Ｌｕ］、［Ｓｃ］、［Ｏ］、［Ｎ］、及び［Ｓ］は、各元素の含有量［質量％］であり、元素を含有しない場合は０である。 Here, the atomic weights of Fe, O, N and S and each X element are Fe: 55.845, O: 15.9994, N: 14.0069, S: 32.068, Pr: 140.908, Sm, respectively. : 150.36, Eu: 151.964, Gd: 157.25, Tb: 158.925, Dy: 162.500, Ho: 164.930, Er: 167.259, Tm: 168.934, Yb: 173 .045, Lu: 174.967, Sc: 44.9559. Therefore, by substituting the atomic weight of each element into the above formula A and arranging it, the effective amount of the element X in terms of atomic% can be approximately expressed by the following formula B.
Effective amount = 0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] ] +0.33 [Tm] +0.32 [Yb] +0.32 [Lu] +1.24 [Sc] -2.33 [O] -3.99 [N] -1.74 [S] ... B
Here, [Pr], [Sm], [Eu], [Gd], [Tb], [Dy], [Ho], [Er], [Tm], [Yb], [Lu], [Sc]. , [O], [N], and [S] are the content [mass%] of each element, and are 0 when the element is not contained.
有効量＝０．４０［Ｐｒ］＋０．３７［Ｓｍ］＋０．３７［Ｅｕ］＋０．３６［Ｇｄ］＋０．３５［Ｔｂ］＋０．３４［Ｄｙ］＋０．３４［Ｈｏ］＋０．３３［Ｅｒ］＋０．３３［Ｔｍ］＋０．３２［Ｙｂ］＋０．３２［Ｌｕ］＋１．２４［Ｓｃ］－２．３３［Ｏ］－３．９９［Ｎ］－１．７４［Ｓ］ ・・・式Ｂ
ここで、［Ｐｒ］、［Ｓｍ］、［Ｅｕ］、［Ｇｄ］、［Ｔｂ］、［Ｄｙ］、［Ｈｏ］、［Ｅｒ］、［Ｔｍ］、［Ｙｂ］、［Ｌｕ］、［Ｓｃ］、［Ｏ］、［Ｎ］、及び［Ｓ］は、各元素の含有量［質量％］であり、元素を含有しない場合は０である。 Here, the atomic weights of Fe, O, N and S and each X element are Fe: 55.845, O: 15.9994, N: 14.0069, S: 32.068, Pr: 140.908, Sm, respectively. : 150.36, Eu: 151.964, Gd: 157.25, Tb: 158.925, Dy: 162.500, Ho: 164.930, Er: 167.259, Tm: 168.934, Yb: 173 .045, Lu: 174.967, Sc: 44.9559. Therefore, by substituting the atomic weight of each element into the above formula A and arranging it, the effective amount of the element X in terms of atomic% can be approximately expressed by the following formula B.
Effective amount = 0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] ] +0.33 [Tm] +0.32 [Yb] +0.32 [Lu] +1.24 [Sc] -2.33 [O] -3.99 [N] -1.74 [S] ... B
Here, [Pr], [Sm], [Eu], [Gd], [Tb], [Dy], [Ho], [Er], [Tm], [Yb], [Lu], [Sc]. , [O], [N], and [S] are the content [mass%] of each element, and are 0 when the element is not contained.
本発明の実施形態においては、リン化物を形成するためには、上記式Ｂによって求められるＸ元素の有効量は０．０００３％以上、すなわち下記式１を満たすことが少なくとも必要である。
０．４０［Ｐｒ］＋０．３７［Ｓｍ］＋０．３７［Ｅｕ］＋０．３６［Ｇｄ］＋０．３５［Ｔｂ］＋０．３４［Ｄｙ］＋０．３４［Ｈｏ］＋０．３３［Ｅｒ］＋０．３３［Ｔｍ］＋０．３２［Ｙｂ］＋０．３２［Ｌｕ］＋１．２４［Ｓｃ］－２．３３［Ｏ］－３．９９［Ｎ］－１．７４［Ｓ］ ≧ ０．０００３ ・・・式１
Ｘ元素の有効量は、例えば０．０００５％以上又は０．０００７％以上であってもよく、好ましくは０．００１０％以上、より好ましくは０．００１５％以上、さらにより好ましくは０．００３０％以上、最も好ましくは０．００５０％以上又は０．０１００％以上である。また、上記式１からも明らかなように、当該有効量を安定的に確保するためには、鋼中のＯ、Ｎ及びＳの含有量を極力低減することが好ましい。ここで、Ｘ元素の有効量の上限は特に限定されないが、当該Ｘ元素の有効量を過度に増加させても効果が飽和するとともに、製造コストの上昇（Ｘ元素の含有量増加に伴う合金コストの上昇及び／又はＯ、Ｎ及びＳに関する精錬コストの上昇）を招くことになり必ずしも好ましくない。したがって、Ｘ元素の有効量は好ましくは２．００００％以下であり、例えば１．８０００％以下、１．５０００％以下、１．２０００％以下、１．００００％以下又は０．８０００％以下であってもよい。 In the embodiment of the present invention, in order to form a phosphide, it is necessary that the effective amount of the X element determined by the above formula B is 0.0003% or more, that is, at least satisfy the followingformula 1.
0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] +0. 33 [Tm] +0.32 [Yb] +0.32 [Lu] +1.24 [Sc] -2.33 [O] -3.99 [N] -1.74 [S] ≧ 0.0003 ...Equation 1
The effective amount of the X element may be, for example, 0.0005% or more or 0.0007% or more, preferably 0.0010% or more, more preferably 0.0015% or more, still more preferably 0.0030%. The above is most preferably 0.0050% or more or 0.0100% or more. Further, as is clear from theabove formula 1, in order to stably secure the effective amount, it is preferable to reduce the contents of O, N and S in the steel as much as possible. Here, the upper limit of the effective amount of the X element is not particularly limited, but even if the effective amount of the X element is excessively increased, the effect is saturated and the manufacturing cost increases (alloy cost due to the increase in the content of the X element). And / or an increase in refining cost for O, N and S), which is not always preferable. Therefore, the effective amount of element X is preferably 2.000% or less, for example, 1.8000% or less, 1.5000% or less, 1.2000% or less, 1.000% or less, or 0.8000% or less. You may.
０．４０［Ｐｒ］＋０．３７［Ｓｍ］＋０．３７［Ｅｕ］＋０．３６［Ｇｄ］＋０．３５［Ｔｂ］＋０．３４［Ｄｙ］＋０．３４［Ｈｏ］＋０．３３［Ｅｒ］＋０．３３［Ｔｍ］＋０．３２［Ｙｂ］＋０．３２［Ｌｕ］＋１．２４［Ｓｃ］－２．３３［Ｏ］－３．９９［Ｎ］－１．７４［Ｓ］ ≧ ０．０００３ ・・・式１
Ｘ元素の有効量は、例えば０．０００５％以上又は０．０００７％以上であってもよく、好ましくは０．００１０％以上、より好ましくは０．００１５％以上、さらにより好ましくは０．００３０％以上、最も好ましくは０．００５０％以上又は０．０１００％以上である。また、上記式１からも明らかなように、当該有効量を安定的に確保するためには、鋼中のＯ、Ｎ及びＳの含有量を極力低減することが好ましい。ここで、Ｘ元素の有効量の上限は特に限定されないが、当該Ｘ元素の有効量を過度に増加させても効果が飽和するとともに、製造コストの上昇（Ｘ元素の含有量増加に伴う合金コストの上昇及び／又はＯ、Ｎ及びＳに関する精錬コストの上昇）を招くことになり必ずしも好ましくない。したがって、Ｘ元素の有効量は好ましくは２．００００％以下であり、例えば１．８０００％以下、１．５０００％以下、１．２０００％以下、１．００００％以下又は０．８０００％以下であってもよい。 In the embodiment of the present invention, in order to form a phosphide, it is necessary that the effective amount of the X element determined by the above formula B is 0.0003% or more, that is, at least satisfy the following
0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] +0. 33 [Tm] +0.32 [Yb] +0.32 [Lu] +1.24 [Sc] -2.33 [O] -3.99 [N] -1.74 [S] ≧ 0.0003 ...
The effective amount of the X element may be, for example, 0.0005% or more or 0.0007% or more, preferably 0.0010% or more, more preferably 0.0015% or more, still more preferably 0.0030%. The above is most preferably 0.0050% or more or 0.0100% or more. Further, as is clear from the
［抽出残渣法によって測定されるリン化物に含まれるＰ量が鋼材に対して０．０００３原子％以上］
本発明の実施形態においては、Ｘ元素がＰと反応してリン化物を形成し、当該リン化物がピン止め粒子として有効に機能することができる量において鋼中に存在する必要がある。本発明の実施形態においては、Ｘ元素を含有するリン化物が鋼中に存在し、抽出残渣法によって測定される当該リン化物に含まれるＰ量が鋼材に対して０．０００３原子％以上の要件を満たす場合には、当該リン化物がピン止め粒子として有効に機能し、金属組織の粒成長を顕著に抑制することが可能となる。上記のＰ量は、好ましくは０．０００５原子％以上、より好ましくは０．００１０原子％以上、さらにより好ましくは０．００３０原子％以上、最も好ましくは０．００５０原子％以上又は０．０１００原子％以上である。当該Ｐ量の上限は特に限定されないが、当該Ｐ量を過度に増加させても効果が飽和するとともに、製造コストの上昇（リン化物を形成するためのＸ元素の含有量増加に伴う合金コストの上昇及び／又はＯ、Ｎ及びＳに関する精錬コストの上昇）を招くことになり必ずしも好ましくない。したがって、当該Ｐ量は好ましくは０．５０００原子％以下であり、例えば０．４０００原子％以下、０．３０００原子％以下、０．２０００原子％以下、０．１５００原子％以下又は０．１０００原子％以下であってもよい。 [The amount of P contained in the phosphide measured by the extraction residue method is 0.0003 atomic% or more with respect to the steel material]
In an embodiment of the invention, element X needs to react with P to form a phosphide and be present in the steel in an amount capable of the phosphide effectively functioning as pinning particles. In the embodiment of the present invention, a phosphonic acid substance containing an element X is present in the steel, and the amount of P contained in the phosphor compound measured by the extraction residue method is required to be 0.0003 atomic% or more with respect to the steel material. When the condition is satisfied, the phosphonic acid product effectively functions as a pinning particle, and the grain growth of the metal structure can be remarkably suppressed. The above amount of P is preferably 0.0005 atom% or more, more preferably 0.0010 atom% or more, still more preferably 0.0030 atom% or more, most preferably 0.0050 atom% or more or 0.0100 atom. % Or more. The upper limit of the P amount is not particularly limited, but even if the P amount is excessively increased, the effect is saturated and the production cost is increased (the alloy cost due to the increase in the content of the X element for forming the phosphite). It is not always preferable because it causes an increase and / or an increase in the refining cost for O, N and S). Therefore, the amount of P is preferably 0.5000 atom% or less, for example, 0.4000 atom% or less, 0.3000 atom% or less, 0.2000 atom% or less, 0.1500 atom% or less, or 0.1000 atom. It may be less than or equal to%.
本発明の実施形態においては、Ｘ元素がＰと反応してリン化物を形成し、当該リン化物がピン止め粒子として有効に機能することができる量において鋼中に存在する必要がある。本発明の実施形態においては、Ｘ元素を含有するリン化物が鋼中に存在し、抽出残渣法によって測定される当該リン化物に含まれるＰ量が鋼材に対して０．０００３原子％以上の要件を満たす場合には、当該リン化物がピン止め粒子として有効に機能し、金属組織の粒成長を顕著に抑制することが可能となる。上記のＰ量は、好ましくは０．０００５原子％以上、より好ましくは０．００１０原子％以上、さらにより好ましくは０．００３０原子％以上、最も好ましくは０．００５０原子％以上又は０．０１００原子％以上である。当該Ｐ量の上限は特に限定されないが、当該Ｐ量を過度に増加させても効果が飽和するとともに、製造コストの上昇（リン化物を形成するためのＸ元素の含有量増加に伴う合金コストの上昇及び／又はＯ、Ｎ及びＳに関する精錬コストの上昇）を招くことになり必ずしも好ましくない。したがって、当該Ｐ量は好ましくは０．５０００原子％以下であり、例えば０．４０００原子％以下、０．３０００原子％以下、０．２０００原子％以下、０．１５００原子％以下又は０．１０００原子％以下であってもよい。 [The amount of P contained in the phosphide measured by the extraction residue method is 0.0003 atomic% or more with respect to the steel material]
In an embodiment of the invention, element X needs to react with P to form a phosphide and be present in the steel in an amount capable of the phosphide effectively functioning as pinning particles. In the embodiment of the present invention, a phosphonic acid substance containing an element X is present in the steel, and the amount of P contained in the phosphor compound measured by the extraction residue method is required to be 0.0003 atomic% or more with respect to the steel material. When the condition is satisfied, the phosphonic acid product effectively functions as a pinning particle, and the grain growth of the metal structure can be remarkably suppressed. The above amount of P is preferably 0.0005 atom% or more, more preferably 0.0010 atom% or more, still more preferably 0.0030 atom% or more, most preferably 0.0050 atom% or more or 0.0100 atom. % Or more. The upper limit of the P amount is not particularly limited, but even if the P amount is excessively increased, the effect is saturated and the production cost is increased (the alloy cost due to the increase in the content of the X element for forming the phosphite). It is not always preferable because it causes an increase and / or an increase in the refining cost for O, N and S). Therefore, the amount of P is preferably 0.5000 atom% or less, for example, 0.4000 atom% or less, 0.3000 atom% or less, 0.2000 atom% or less, 0.1500 atom% or less, or 0.1000 atom. It may be less than or equal to%.
［抽出残渣法によるＰ量の測定］
リン化物に含まれるＰ量は抽出残渣法によって以下のように決定される。まず、鋼材から採取した鋼材表面から０．５ｍｍ深さ位置を含む試料を定電流電解によって鋼材１ｇ以上を電解し、次いで孔径０．２μｍのメンブレンフィルタを用いて濾過し、析出物（リン化物）が分離される。次に、分離した析出物を硝酸（ＨＮＯ3）等の溶液にて分解し、次いで得られた残渣をＩＣＰ－ＭＳ（誘導結合プラズマ質量分析計）で測定することにより鋼材中に析出したリン化物として存在しているＰ量が得られる。最後に、当該Ｐ量と電解した鋼材の具体的な量からリン化物に含まれるＰ量の鋼材全体に対する割合（原子％）が決定される。 [Measurement of P amount by extraction residue method]
The amount of P contained in the phosphide is determined as follows by the extraction residue method. First, a sample containing a depth of 0.5 mm from the surface of the steel material collected from the steel material is electrolyzed with 1 g or more of the steel material by constant current electrolysis, and then filtered using a membrane filter having a pore size of 0.2 μm to form a precipitate (phosphide). Is separated. Next, the separated precipitate was decomposed with a solution such as nitrate (HNO 3 ), and then the obtained residue was measured by ICP-MS (inductively coupled plasma mass spectrometer). The amount of P present as is obtained. Finally, the ratio (atomic%) of the amount of P contained in the phosphide to the whole steel material is determined from the amount of P and the specific amount of the electrolyzed steel material.
リン化物に含まれるＰ量は抽出残渣法によって以下のように決定される。まず、鋼材から採取した鋼材表面から０．５ｍｍ深さ位置を含む試料を定電流電解によって鋼材１ｇ以上を電解し、次いで孔径０．２μｍのメンブレンフィルタを用いて濾過し、析出物（リン化物）が分離される。次に、分離した析出物を硝酸（ＨＮＯ3）等の溶液にて分解し、次いで得られた残渣をＩＣＰ－ＭＳ（誘導結合プラズマ質量分析計）で測定することにより鋼材中に析出したリン化物として存在しているＰ量が得られる。最後に、当該Ｐ量と電解した鋼材の具体的な量からリン化物に含まれるＰ量の鋼材全体に対する割合（原子％）が決定される。 [Measurement of P amount by extraction residue method]
The amount of P contained in the phosphide is determined as follows by the extraction residue method. First, a sample containing a depth of 0.5 mm from the surface of the steel material collected from the steel material is electrolyzed with 1 g or more of the steel material by constant current electrolysis, and then filtered using a membrane filter having a pore size of 0.2 μm to form a precipitate (phosphide). Is separated. Next, the separated precipitate was decomposed with a solution such as nitrate (HNO 3 ), and then the obtained residue was measured by ICP-MS (inductively coupled plasma mass spectrometer). The amount of P present as is obtained. Finally, the ratio (atomic%) of the amount of P contained in the phosphide to the whole steel material is determined from the amount of P and the specific amount of the electrolyzed steel material.
［ＴＥＭレプリカ法によって測定されるリン化物の平均粒径が１００ｎｍ未満］
ピン止め粒子としては、微細な粒子が比較的多く存在することが一般的に有効である。本発明の実施形態においては、リン化物を平均粒径が１００ｎｍ未満の微細なリン化物として存在させることで、当該リン化物により金属組織の粒成長を確実に抑制することが可能となる。リン化物の平均粒径は、好ましくは９０ｎｍ以下、より好ましくは８０ｎｍ以下、さらにより好ましくは６０ｎｍ以下、最も好ましくは５０ｎｍ以下又は４０ｎｍ以下である。リン化物の平均粒径の下限は特に限定されないが、例えば５ｎｍ以上であり、８ｎｍ以上、１０ｎｍ以上、１５ｎｍ以上、２０ｎｍ以上又は２５ｎｍ以上であってもよい。 [Average particle size of phosphide measured by TEM replica method is less than 100 nm]
As the pinning particles, it is generally effective that a relatively large number of fine particles are present. In the embodiment of the present invention, by allowing the phosphide to exist as a fine phosphide having an average particle size of less than 100 nm, the phosphide can surely suppress the grain growth of the metal structure. The average particle size of the phosphide is preferably 90 nm or less, more preferably 80 nm or less, even more preferably 60 nm or less, and most preferably 50 nm or less or 40 nm or less. The lower limit of the average particle size of the phosphide is not particularly limited, but may be, for example, 5 nm or more, and may be 8 nm or more, 10 nm or more, 15 nm or more, 20 nm or more, or 25 nm or more.
ピン止め粒子としては、微細な粒子が比較的多く存在することが一般的に有効である。本発明の実施形態においては、リン化物を平均粒径が１００ｎｍ未満の微細なリン化物として存在させることで、当該リン化物により金属組織の粒成長を確実に抑制することが可能となる。リン化物の平均粒径は、好ましくは９０ｎｍ以下、より好ましくは８０ｎｍ以下、さらにより好ましくは６０ｎｍ以下、最も好ましくは５０ｎｍ以下又は４０ｎｍ以下である。リン化物の平均粒径の下限は特に限定されないが、例えば５ｎｍ以上であり、８ｎｍ以上、１０ｎｍ以上、１５ｎｍ以上、２０ｎｍ以上又は２５ｎｍ以上であってもよい。 [Average particle size of phosphide measured by TEM replica method is less than 100 nm]
As the pinning particles, it is generally effective that a relatively large number of fine particles are present. In the embodiment of the present invention, by allowing the phosphide to exist as a fine phosphide having an average particle size of less than 100 nm, the phosphide can surely suppress the grain growth of the metal structure. The average particle size of the phosphide is preferably 90 nm or less, more preferably 80 nm or less, even more preferably 60 nm or less, and most preferably 50 nm or less or 40 nm or less. The lower limit of the average particle size of the phosphide is not particularly limited, but may be, for example, 5 nm or more, and may be 8 nm or more, 10 nm or more, 15 nm or more, 20 nm or more, or 25 nm or more.
［ＴＥＭレプリカ法による平均粒径の測定］
リン化物の平均粒径はＴＥＭレプリカ法によって以下のように決定される。まず、鋼材から析出物観察用試験片を採取し、圧延方向に平行でかつ鋼材表面から０．５ｍｍ深さ位置における断面を研磨し、次いでＳＰＥＥＤ法（選択的定電位電解エッチング法）によりエッチングを行い、析出物をブランクレプリカ法によりカーボン膜に抽出してＣｕメッシュ上に保持する。次に、作製したカーボン抽出レプリカ試料を用いてＥＤＳ（エネルギー分散型Ｘ線分光器）による分析を行い、リン化物を同定するとともに、当該リン化物をＴＥＭ（透過型電子顕微鏡、加速電圧２００ｋＶ）を用いて、倍率２００００倍で５０μｍ2の視野を１０視野観察し、個々のリン化物の粒径を円相当直径として算出し、算出された全ての円相当直径の平均値をリン化物の平均粒径として決定する。 [Measurement of average particle size by TEM replica method]
The average particle size of the phosphide is determined by the TEM replica method as follows. First, a test piece for observing precipitates is collected from the steel material, the cross section is polished parallel to the rolling direction and at a depth of 0.5 mm from the surface of the steel material, and then etching is performed by the SPEED method (selective constant potential electrolytic etching method). Then, the precipitate is extracted into a carbon film by the blank replica method and held on the Cu mesh. Next, the prepared carbon extraction replica sample was analyzed by EDS (energy dispersion type X-ray spectroscope) to identify the phosphonic acid, and TEM (transmission electron microscope, acceleration voltage 200 kV) was applied to the phosphonic acid. Using this, 10 visual fields of 50 μm 2 were observed at a magnification of 20000 times, the particle size of each phosphonic acid was calculated as the diameter equivalent to a circle, and the average value of all the calculated diameters equivalent to the circle was the average particle size of the phosphonic acid. To be determined as.
リン化物の平均粒径はＴＥＭレプリカ法によって以下のように決定される。まず、鋼材から析出物観察用試験片を採取し、圧延方向に平行でかつ鋼材表面から０．５ｍｍ深さ位置における断面を研磨し、次いでＳＰＥＥＤ法（選択的定電位電解エッチング法）によりエッチングを行い、析出物をブランクレプリカ法によりカーボン膜に抽出してＣｕメッシュ上に保持する。次に、作製したカーボン抽出レプリカ試料を用いてＥＤＳ（エネルギー分散型Ｘ線分光器）による分析を行い、リン化物を同定するとともに、当該リン化物をＴＥＭ（透過型電子顕微鏡、加速電圧２００ｋＶ）を用いて、倍率２００００倍で５０μｍ2の視野を１０視野観察し、個々のリン化物の粒径を円相当直径として算出し、算出された全ての円相当直径の平均値をリン化物の平均粒径として決定する。 [Measurement of average particle size by TEM replica method]
The average particle size of the phosphide is determined by the TEM replica method as follows. First, a test piece for observing precipitates is collected from the steel material, the cross section is polished parallel to the rolling direction and at a depth of 0.5 mm from the surface of the steel material, and then etching is performed by the SPEED method (selective constant potential electrolytic etching method). Then, the precipitate is extracted into a carbon film by the blank replica method and held on the Cu mesh. Next, the prepared carbon extraction replica sample was analyzed by EDS (energy dispersion type X-ray spectroscope) to identify the phosphonic acid, and TEM (transmission electron microscope, acceleration voltage 200 kV) was applied to the phosphonic acid. Using this, 10 visual fields of 50 μm 2 were observed at a magnification of 20000 times, the particle size of each phosphonic acid was calculated as the diameter equivalent to a circle, and the average value of all the calculated diameters equivalent to the circle was the average particle size of the phosphonic acid. To be determined as.
本発明の実施形態に係る鋼材は、Ｘ元素を含有するリン化物が形成された任意の鋼材であってよく、特に限定されない。本発明の実施形態に係る鋼材は、例えば、熱間圧延後の鋼材である厚鋼板、薄鋼板、さらには棒鋼、線材、形鋼、及び鋼管等をも包含するものである。
The steel material according to the embodiment of the present invention may be any steel material on which a phosphide containing an element X is formed, and is not particularly limited. The steel material according to the embodiment of the present invention includes, for example, thick steel plates and thin steel plates which are steel materials after hot rolling, as well as steel bars, wire rods, shaped steels, steel pipes, and the like.
本発明の実施形態に係る鋼材は、最終的な製品の形態等に応じて、当業者に公知の任意の適切な方法によって製造することが可能である。例えば、鋼材が厚鋼板の場合には、その製造方法は、一般に厚鋼板を製造する際に適用される工程を含み、例えば、上で説明した化学組成を有するスラブを鋳造する工程、鋳造されたスラブを熱間圧延する工程、及び得られた圧延材を冷却する工程を含み、必要に応じて焼入れ工程及び焼戻し工程等の熱処理をさらに含んでいてもよい。本発明の実施形態に係る鋼材の製造工程は、制御圧延と加速冷却を組み合わせた熱加工制御プロセス（ＴＭＣＰ）であってもよい。
The steel material according to the embodiment of the present invention can be manufactured by any suitable method known to those skilled in the art, depending on the form of the final product and the like. For example, when the steel material is a thick steel plate, the manufacturing method includes a step generally applied when manufacturing the thick steel plate, for example, a step of casting a slab having the chemical composition described above, and casting. It includes a step of hot rolling the slab and a step of cooling the obtained rolled material, and may further include heat treatment such as a quenching step and a tempering step, if necessary. The steel material manufacturing process according to the embodiment of the present invention may be a thermal processing control process (TMCP) that combines controlled rolling and accelerated cooling.
また、鋼材が薄鋼板の場合には、その製造方法は、一般に薄鋼板を製造する際に適用される工程を含み、例えば、上で説明した化学組成を有するスラブを鋳造する工程、鋳造されたスラブを熱間圧延する工程、及び得られた圧延材を冷却して巻き取る工程、必要に応じて冷間圧延工程、焼鈍工程等をさらに含んでいてもよい。棒鋼や他の鋼材の製造方法においても同様に、一般に棒鋼や他の鋼材を製造する際に適用される工程を含み、例えば、上で説明した化学組成を有する溶鋼を形成する製鋼工程、形成された溶鋼からスラブ、ビレット、ブルーム等を鋳造する工程、鋳造されたスラブ、ビレット、ブルーム等を熱間圧延する工程、及び得られた圧延材を冷却する工程を含み、他の工程は、それらの鋼材を製造するのに当業者に公知の適切な工程を適宜選択し、実施することができる。
Further, when the steel material is a thin steel plate, the manufacturing method includes a step generally applied when manufacturing the thin steel plate, for example, a step of casting a slab having the chemical composition described above, and casting. It may further include a step of hot rolling the slab, a step of cooling and winding the obtained rolled material, a cold rolling step, a baking step and the like, if necessary. Similarly, a method for manufacturing steel bars and other steel materials also includes a process generally applied when manufacturing steel bars and other steel materials, for example, a steelmaking process for forming molten steel having the chemical composition described above. It includes a step of casting slabs, billets, blooms, etc. from molten steel, a step of hot rolling the cast slabs, billets, blooms, etc., and a step of cooling the obtained rolled material, and other steps include those steps. Appropriate steps known to those skilled in the art for producing steel materials can be appropriately selected and carried out.
熱間圧延工程での熱履歴はリン化物の生成のために重要である。例えば、熱間圧延工程の加熱温度、付加される歪みの影響も考慮し、各Ｘ元素のリン化物が析出する温度と時間の範囲（リン化物の析出ノーズ）を予め定めておき、当該熱間圧延工程での熱履歴をこの温度と時間の範囲内（すなわちリン化物の析出ノーズ内）に導くようにすればよい。図面を参照して以下により詳しく説明する。図１は、Ｘ元素を含有するリン化物の析出ノーズを示す模式図である。図１は上記のとおり模式図であり、実際には具体的に用いられるＸ元素等に応じて析出ノーズの曲線は変化する。図１を参照すると、熱間圧延による加工がある場合には、リン化物の析出ノーズ（図１中の実線）が短時間側にシフトする。例えば、９５０～１１００℃の範囲で歪みを付加した後、この温度範囲で約３０秒以上（より低い温度の場合には約７０秒以上）の比較的短い時間保持し、次いで冷却することで、熱間圧延工程での熱履歴が析出ノーズ内を通るため、Ｘ元素と鋼中のＰを反応させてリン化物を形成することができる。一方で、熱間圧延による加工がある場合であっても、例えば、１１００℃以上の高温下で歪みを付加し、９５０～１１００℃の範囲で約１０秒程度の短い時間保持した後に冷却した場合には、熱間圧延工程での熱履歴が析出ノーズ内を通らず、リン化物を形成することができない場合がある。「保持」とは、上記の温度範囲内で放冷又は空冷等により徐々に温度が低下する場合を包含するものである。
The thermal history in the hot rolling process is important for the formation of phosphide. For example, in consideration of the heating temperature of the hot rolling process and the influence of the added strain, the temperature and time range (phosphorization nose) at which the phosphite of each X element is precipitated is determined in advance, and the hotness is determined. The thermal history of the rolling process may be guided within this temperature and time range (ie, within the precipitation nose of the phosphite). It will be described in more detail below with reference to the drawings. FIG. 1 is a schematic diagram showing a precipitation nose of a phosphide containing element X. FIG. 1 is a schematic diagram as described above, and the curve of the precipitation nose actually changes depending on the X element or the like specifically used. Referring to FIG. 1, when there is processing by hot rolling, the precipitation nose of the phosphide (solid line in FIG. 1) shifts to the short-time side. For example, after applying strain in the range of 950 to 1100 ° C., it is held in this temperature range for a relatively short time of about 30 seconds or more (about 70 seconds or more in the case of a lower temperature), and then cooled. Since the thermal history in the hot rolling process passes through the precipitation nose, element X and P in the steel can be reacted to form a phosphide. On the other hand, even when processing by hot rolling is performed, for example, when strain is applied at a high temperature of 1100 ° C. or higher, and the mixture is held in the range of 950 to 1100 ° C. for a short time of about 10 seconds and then cooled. In some cases, the heat history in the hot rolling process does not pass through the precipitation nose and phosphide cannot be formed. The term "retention" includes a case where the temperature gradually decreases due to cooling, air cooling, or the like within the above temperature range.
熱間圧延工程はスラブ、ビレット、ブルームの加熱後、粗圧延及び／又は仕上げ圧延の終了までの工程である。この工程での具体的な熱履歴は、Ｘ元素の種類等によっても変化するため、特に限定されないが、例えば、当該熱履歴は、粗圧延及び／又は仕上げ圧延の途中、あるいは、粗圧延及び／又は仕上げ圧延後、９００～１１００℃、好ましくは９５０～１１００℃の温度範囲において３０秒以上保持することを含むものである。あるいはまた、熱履歴は、熱間圧延で歪みを付加する前に９５０～１１００℃、好ましくは９８０～１０２０℃で１０００秒以上保持することを含むものであってもよい。この場合には、熱間圧延で歪みを付加する前にリン化物が形成される。保持時間の上限は、特に限定されないが、例えば１５０００秒以下又は１２０００秒以下であってよい。熱間圧延工程にこのような熱履歴を含めることで、オーステナイト中に存在しているＸ元素を鋼中のＰと確実に反応させてリン化物を形成することができるため、ピン止め効果により金属組織の粒成長を顕著に抑制することができる。その結果として、例えば、得られる鋼材の低温靭性を向上させ及び／又は高強度と低温靭性の両立を図ることが可能となる。リン化物の微細化の観点から、当該熱履歴は、粗圧延及び／又は仕上げ圧延の途中、あるいは、粗圧延及び／又は仕上げ圧延後に含めることが好ましい。また、本発明の実施形態に係る鋼材の製造では、Ｐとリン化物を形成するためのＸ元素の有効量を確保することも重要であり、そのためにはＸ元素と鋼中で介在物を形成し得るＯ、Ｎ及びＳの含有量を精錬工程において十分に低減しておくことが極めて重要である。
The hot rolling process is a process from heating the slab, billet, and bloom to the end of rough rolling and / or finish rolling. The specific thermal history in this step is not particularly limited because it changes depending on the type of element X and the like, but the thermal history is, for example, during rough rolling and / or finish rolling, or during rough rolling and / or rough rolling and /. Alternatively, it includes holding for 30 seconds or more in a temperature range of 900 to 1100 ° C., preferably 950 to 1100 ° C. after finish rolling. Alternatively, the thermal history may include holding at 950 to 1100 ° C., preferably 980 to 1020 ° C. for 1000 seconds or longer before adding strain in hot rolling. In this case, phosphide is formed before strain is applied by hot rolling. The upper limit of the holding time is not particularly limited, but may be, for example, 15,000 seconds or less or 12,000 seconds or less. By including such a thermal history in the hot rolling process, the X element present in austenite can be reliably reacted with P in the steel to form a phosphide, so that the metal can be pinned by the pinning effect. The grain growth of the tissue can be remarkably suppressed. As a result, for example, it is possible to improve the low temperature toughness of the obtained steel material and / or achieve both high strength and low temperature toughness. From the viewpoint of miniaturization of the phosphide, it is preferable to include the thermal history during rough rolling and / or finish rolling, or after rough rolling and / or finish rolling. Further, in the production of the steel material according to the embodiment of the present invention, it is also important to secure an effective amount of X element for forming P and a phospho compound, and for that purpose, inclusions are formed in the X element and the steel. It is extremely important to sufficiently reduce the possible O, N and S contents in the refining process.
以下、実施例によって本発明をより詳細に説明するが、本発明はこれらの実施例に何ら限定されるものではない。
Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.
本例では、まず、種々の化学組成を有するスラブを鋳造し、次いで下表１に示す製造条件Ａ～Ｄ（熱間圧延工程における熱履歴）にて、加熱、粗圧延及び仕上げ圧延（粗圧延と仕上げ圧延の合計圧下率：５０％以上）を実施して鋼材を製造した。
In this example, first, slabs having various chemical compositions are cast, and then heating, rough rolling and finish rolling (rough rolling) are performed under the manufacturing conditions A to D (heat history in the hot rolling process) shown in Table 1 below. And the total rolling reduction of the finish rolling: 50% or more) was carried out to manufacture the steel material.
次いで、鋼材から試験片を採取し、当該試験片をＡｃ３点以上に加熱した際のオーステナイト粒径をＪＩＳ Ｇ ０５５１：２０１３に準拠した切断法により測定することで金属組織の粒成長抑制効果を評価した。Ａｃ３点は、加熱時にフェライトからオーステナイトへの変態が完了する温度である。具体的には、試験片を昇温速度２０℃／秒で９５０℃まで加熱し１０秒保持した場合のオーステナイト粒径をＤ１、同様に試験片を昇温速度２０℃／秒で１０５０℃まで加熱し１０秒保持した場合のオーステナイト粒径をＤ２とした。微細なリン化物が多く形成されている場合には、ピン止め効果により高温下での粒成長が抑制される。したがって、リン化物によるピン止め効果が有効に機能している場合には、Ｄ２はＤ１に近づいていき、すなわちＤ２／Ｄ１は１に近づいていくことになる。したがって、Ｄ２／Ｄ１を算出することにより、その鋼材が有する粒成長抑制効果を評価することが可能である。本実施例では、Ｄ２／Ｄ１が１．５０以下の場合に、金属組織の粒成長が抑制されているものとして評価した。その結果を下表２に示す。加えて、得られた各鋼材から採取した試料を分析した化学組成、各鋼材中のリン化物に含まれるＰ量（析出Ｐ量）及び当該リン化物の平均粒径についても下表２に示す。リン化物に含まれるＰ量及び当該リン化物の平均粒径は以下の方法によって測定した。
Next, a test piece was collected from the steel material, and the austenite particle size when the test piece was heated to Ac3 or higher was measured by a cutting method based on JIS G0551: 2013 to evaluate the effect of suppressing grain growth of the metal structure. did. The Ac3 point is the temperature at which the transformation from ferrite to austenite is completed during heating. Specifically, the austenite particle size when the test piece is heated to 950 ° C. at a heating rate of 20 ° C./sec and held for 10 seconds is D1, and similarly, the test piece is heated to 1050 ° C. at a heating rate of 20 ° C./sec. The austenite particle size when held for 10 seconds was defined as D2. When a large amount of fine phosphide is formed, grain growth at high temperature is suppressed by the pinning effect. Therefore, when the pinning effect of the phosphide is functioning effectively, D2 approaches D1, that is, D2 / D1 approaches 1. Therefore, by calculating D2 / D1, it is possible to evaluate the grain growth suppressing effect of the steel material. In this example, when D2 / D1 was 1.50 or less, it was evaluated as having suppressed grain growth of the metal structure. The results are shown in Table 2 below. In addition, Table 2 below also shows the chemical composition obtained by analyzing the sample collected from each of the obtained steel materials, the amount of P contained in the phosphide in each steel material (precipitated P amount), and the average particle size of the phosphide. The amount of P contained in the phosphide and the average particle size of the phosphide were measured by the following methods.
［リン化物に含まれるＰ量の測定］
リン化物に含まれるＰ量は抽出残渣法によって以下のように決定した。まず、鋼材から採取した鋼材表面から０．５ｍｍ深さ位置を含む試料を１０％アセチルアセトン－１％テトラメチルアンモニウムクロライド－メタノール溶液中５００ｍｍＡ及び２時間以上の条件下での定電流電解によって鋼材１ｇ以上を電解し、次いで孔径０．２μｍのメンブレンフィルタを用いて濾過し、析出物（リン化物）を分離した。次に、分離した析出物を硝酸（ＨＮＯ3）と過塩素酸（ＨＣｌＯ4）を２：１で混合した溶液にて分解し、次いで得られた残渣をＩＣＰ－ＭＳ（誘導結合プラズマ質量分析計）で測定することにより鋼材中に析出したリン化物として存在しているＰ量を得た。最後に、当該Ｐ量と電解した鋼材の具体的な量からリン化物に含まれるＰ量の鋼材全体に対する割合（原子％）を決定した。 [Measurement of P contained in phosphide]
The amount of P contained in the phosphide was determined as follows by the extraction residue method. First, a sample containing a depth of 0.5 mm from the surface of the steel material collected from the steel material is subjected to constant current electrolysis under the conditions of 10% acetylacetone-1% tetramethylammonium chloride-methanol solution at 500 mmA and 2 hours or more to obtain 1 g or more of the steel material. Was electrolyzed and then filtered using a membrane filter having a pore size of 0.2 μm to separate precipitates (phosphide). Next, the separated precipitate was decomposed with a solution in which nitric acid (HNO 3 ) and perchloric acid (HClO 4 ) were mixed at a ratio of 2: 1 and the obtained residue was then subjected to ICP-MS (inductively coupled plasma mass spectrometer). ) Was used to obtain the amount of P present as a phosphate precipitated in the steel material. Finally, the ratio (atomic%) of the amount of P contained in the phosphide to the whole steel material was determined from the amount of P and the specific amount of the electrolyzed steel material.
リン化物に含まれるＰ量は抽出残渣法によって以下のように決定した。まず、鋼材から採取した鋼材表面から０．５ｍｍ深さ位置を含む試料を１０％アセチルアセトン－１％テトラメチルアンモニウムクロライド－メタノール溶液中５００ｍｍＡ及び２時間以上の条件下での定電流電解によって鋼材１ｇ以上を電解し、次いで孔径０．２μｍのメンブレンフィルタを用いて濾過し、析出物（リン化物）を分離した。次に、分離した析出物を硝酸（ＨＮＯ3）と過塩素酸（ＨＣｌＯ4）を２：１で混合した溶液にて分解し、次いで得られた残渣をＩＣＰ－ＭＳ（誘導結合プラズマ質量分析計）で測定することにより鋼材中に析出したリン化物として存在しているＰ量を得た。最後に、当該Ｐ量と電解した鋼材の具体的な量からリン化物に含まれるＰ量の鋼材全体に対する割合（原子％）を決定した。 [Measurement of P contained in phosphide]
The amount of P contained in the phosphide was determined as follows by the extraction residue method. First, a sample containing a depth of 0.5 mm from the surface of the steel material collected from the steel material is subjected to constant current electrolysis under the conditions of 10% acetylacetone-1% tetramethylammonium chloride-methanol solution at 500 mmA and 2 hours or more to obtain 1 g or more of the steel material. Was electrolyzed and then filtered using a membrane filter having a pore size of 0.2 μm to separate precipitates (phosphide). Next, the separated precipitate was decomposed with a solution in which nitric acid (HNO 3 ) and perchloric acid (HClO 4 ) were mixed at a ratio of 2: 1 and the obtained residue was then subjected to ICP-MS (inductively coupled plasma mass spectrometer). ) Was used to obtain the amount of P present as a phosphate precipitated in the steel material. Finally, the ratio (atomic%) of the amount of P contained in the phosphide to the whole steel material was determined from the amount of P and the specific amount of the electrolyzed steel material.
［リン化物の平均粒径の測定］
リン化物の平均粒径はＴＥＭレプリカ法によって以下のように決定した。まず、鋼材から析出物観察用試験片を採取し、圧延方向に平行でかつ鋼材表面から０．５ｍｍ深さ位置における断面を研磨し（エメリー紙、ダイアモンドペーストにて鏡面研磨し、次いで研磨面をアルミナ砥粒にて仕上げ研磨）、次いでＳＰＥＥＤ法（選択的定電位電解エッチング法）によりエッチングを行い（電解研磨液：１０％アセチルアセトン－１％テトラメチルアンモニウムクロライド－メタノール、電解研磨条件：－１００ｍＶ ｖｓ ＳＣＥ、１０クーロン／ｃｍ2）、析出物をブランクレプリカ法によりカーボン膜に抽出してＣｕメッシュ上に保持した。次に、作製したカーボン抽出レプリカ試料を用いてＥＤＳ（エネルギー分散型Ｘ線分光器）による分析を行い、リン化物を同定するとともに、当該リン化物をＴＥＭ（透過型電子顕微鏡、加速電圧２００ｋＶ）を用いて、倍率２００００倍で５０μｍ2の視野を１０視野観察し、個々のリン化物の粒径を円相当直径として算出し、算出された全ての円相当直径の平均値をリン化物の平均粒径として決定した。 [Measurement of average particle size of phosphide]
The average particle size of the phosphide was determined by the TEM replica method as follows. First, a test piece for observing precipitates is collected from the steel material, and the cross section parallel to the rolling direction and at a depth of 0.5 mm from the steel material surface is polished (mirror-polished with emery paper or diamond paste, and then the polished surface is polished. Finish polishing with alumina abrasive grains), then etching by SPEED method (selective constant potential electrolytic etching method) (electropolishing solution: 10% acetylacetone-1% tetramethylammonium chloride-methanol, electrolytic polishing conditions: -100 mV vs. SCE, 10 Coulomb / cm 2 ), and the precipitate were extracted into a carbon film by a blank replica method and held on a Cu mesh. Next, the prepared carbon extraction replica sample was analyzed by EDS (energy dispersion type X-ray spectroscope) to identify the phosphonic acid, and TEM (transmission electron microscope, acceleration voltage 200 kV) was applied to the phosphonic acid. Using this, 10 visual fields of 50 μm 2 were observed at a magnification of 20000 times, the particle size of each phosphonic acid was calculated as the diameter equivalent to a circle, and the average value of all the calculated diameters equivalent to the circle was the average particle size of the phosphonic acid. Was decided as.
リン化物の平均粒径はＴＥＭレプリカ法によって以下のように決定した。まず、鋼材から析出物観察用試験片を採取し、圧延方向に平行でかつ鋼材表面から０．５ｍｍ深さ位置における断面を研磨し（エメリー紙、ダイアモンドペーストにて鏡面研磨し、次いで研磨面をアルミナ砥粒にて仕上げ研磨）、次いでＳＰＥＥＤ法（選択的定電位電解エッチング法）によりエッチングを行い（電解研磨液：１０％アセチルアセトン－１％テトラメチルアンモニウムクロライド－メタノール、電解研磨条件：－１００ｍＶ ｖｓ ＳＣＥ、１０クーロン／ｃｍ2）、析出物をブランクレプリカ法によりカーボン膜に抽出してＣｕメッシュ上に保持した。次に、作製したカーボン抽出レプリカ試料を用いてＥＤＳ（エネルギー分散型Ｘ線分光器）による分析を行い、リン化物を同定するとともに、当該リン化物をＴＥＭ（透過型電子顕微鏡、加速電圧２００ｋＶ）を用いて、倍率２００００倍で５０μｍ2の視野を１０視野観察し、個々のリン化物の粒径を円相当直径として算出し、算出された全ての円相当直径の平均値をリン化物の平均粒径として決定した。 [Measurement of average particle size of phosphide]
The average particle size of the phosphide was determined by the TEM replica method as follows. First, a test piece for observing precipitates is collected from the steel material, and the cross section parallel to the rolling direction and at a depth of 0.5 mm from the steel material surface is polished (mirror-polished with emery paper or diamond paste, and then the polished surface is polished. Finish polishing with alumina abrasive grains), then etching by SPEED method (selective constant potential electrolytic etching method) (electropolishing solution: 10% acetylacetone-1% tetramethylammonium chloride-methanol, electrolytic polishing conditions: -100 mV vs. SCE, 10 Coulomb / cm 2 ), and the precipitate were extracted into a carbon film by a blank replica method and held on a Cu mesh. Next, the prepared carbon extraction replica sample was analyzed by EDS (energy dispersion type X-ray spectroscope) to identify the phosphonic acid, and TEM (transmission electron microscope, acceleration voltage 200 kV) was applied to the phosphonic acid. Using this, 10 visual fields of 50 μm 2 were observed at a magnification of 20000 times, the particle size of each phosphonic acid was calculated as the diameter equivalent to a circle, and the average value of all the calculated diameters equivalent to the circle was the average particle size of the phosphonic acid. Was decided as.
表２を参照すると、比較例８４～９１では、Ｐｒ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ、及びＳｃからなるＸ元素の有効量が低かったために、鋼材中のＰをリン化物として析出させることができず、結果として金属組織の粒成長を抑制することができなかった。一方、比較例９２では、Ｘ元素の有効量は０．０００３％よりも高く、それゆえ式１を満足するものであったが、熱間圧延工程での熱履歴が適切でなかったために、リン化物を析出させることができず、結果として金属組織の粒成長を抑制することができなかった。これとは対照的に、本発明に係る全ての実施例において、Ｘ元素の有効量を０．０００３％以上とし、さらにはリン化物に含まれるＰ量及び当該リン化物の平均粒径を適切なものとすることで、金属組織の粒成長を十分に抑制することができた。
Referring to Table 2, in Comparative Examples 84 to 91, the effective amount of the X element composed of Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc was low, so that the steel material was used. The P inside could not be precipitated as a phospholide, and as a result, the grain growth of the metal structure could not be suppressed. On the other hand, in Comparative Example 92, the effective amount of the X element was higher than 0.0003%, and therefore satisfied Equation 1, but the thermal history in the hot rolling step was not appropriate, so that phosphorus was used. The phosphide could not be precipitated, and as a result, the grain growth of the metal structure could not be suppressed. In contrast, in all the embodiments of the present invention, the effective amount of element X is 0.0003% or more, and the amount of P contained in the phosphide and the average particle size of the phosphide are appropriate. By doing so, the grain growth of the metal structure could be sufficiently suppressed.
本発明の実施形態に係る鋼材は、Ｘ元素を含有するリン化物が形成された熱間圧延後の鋼材、例えば、橋梁、建築、造船及び圧力容器等の用途に使用される厚鋼板、自動車及び家電等の用途に使用される薄鋼板、さらには棒鋼、線材、形鋼、及び鋼管等をも包含するものである。これらの材料において本発明の実施形態に係る鋼材を適用した場合には、金属組織の粒成長が抑制され、それゆえ微細な金属組織が安定的に維持されているため、例えば高強度と低温靭性の相反する特性を両立することが可能である。
The steel material according to the embodiment of the present invention includes steel materials after hot rolling in which a phosphonic acid containing an element X is formed, for example, thick steel plates used for bridges, construction, shipbuilding, pressure vessels, and the like, automobiles, and the like. It includes thin steel plates used for applications such as home appliances, as well as steel bars, wire rods, shaped steels, steel pipes, and the like. When the steel material according to the embodiment of the present invention is applied to these materials, the grain growth of the metal structure is suppressed, and therefore the fine metal structure is stably maintained. Therefore, for example, high strength and low temperature toughness. It is possible to achieve both of the contradictory characteristics of.
Claims (5)
- 質量％で、
Ｃ：０．００１～１．０００％、
Ｓｉ：０．０１～３．００％、
Ｍｎ：０．１０～４．５０％、
Ｐ：０．０００５～０．３００％、
Ｓ：０．０３００％以下、
Ａｌ：０．００１～５．０００％、
Ｎ：０．２０００％以下、
Ｏ：０．０１００％以下、
Ｐｒ：０～０．８０００％、Ｓｍ：０～０．８０００％、Ｅｕ：０～０．８０００％、Ｇｄ：０～０．８０００％、Ｔｂ：０～０．８０００％、Ｄｙ：０～０．８０００％、Ｈｏ：０～０．８０００％、Ｅｒ：０～０．８０００％、Ｔｍ：０～０．８０００％、Ｙｂ：０～０．８０００％、Ｌｕ：０～０．８０００％、及びＳｃ：０～０．８０００％からなる群より選択される少なくとも１種のＸ元素、
Ｎｂ：０～３．０００％、
Ｔｉ：０～０．５００％、
Ｔａ：０～０．５００％、
Ｖ：０～１．００％、
Ｃｕ：０～３．００％、
Ｎｉ：０～６０．００％、
Ｃｒ：０～３０．００％、
Ｍｏ：０～５．００％、
Ｗ：０～２．００％、
Ｂ：０～０．０２００％、
Ｃｏ：０～３．００％、
Ｂｅ：０～０．０５０％、
Ａｇ：０～０．５００％、
Ｚｒ：０～０．５０００％、
Ｈｆ：０～０．５０００％、
Ｃａ：０～０．０５００％、
Ｍｇ：０～０．０５００％、
Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種：合計で０～０．５０００％、
Ｓｎ：０～０．３００％、
Ｓｂ：０～０．３００％、
Ｔｅ：０～０．１００％、
Ｓｅ：０～０．１００％、
Ａｓ：０～０．０５０％、
Ｂｉ：０～０．５００％、
Ｐｂ：０～０．５００％、並びに
残部：Ｆｅ及び不純物からなり、
下記式１を満たす化学組成を有し、
前記Ｘ元素を含有するリン化物を含み、抽出残渣法によって測定される前記リン化物に含まれるＰ量が鋼材に対して０．０００３原子％以上であり、かつＴＥＭレプリカ法によって測定される前記リン化物の平均粒径が１００ｎｍ未満である、鋼材。
０．４０［Ｐｒ］＋０．３７［Ｓｍ］＋０．３７［Ｅｕ］＋０．３６［Ｇｄ］＋０．３５［Ｔｂ］＋０．３４［Ｄｙ］＋０．３４［Ｈｏ］＋０．３３［Ｅｒ］＋０．３３［Ｔｍ］＋０．３２［Ｙｂ］＋０．３２［Ｌｕ］＋１．２４［Ｓｃ］－２．３３［Ｏ］－３．９９［Ｎ］－１．７４［Ｓ］ ≧ ０．０００３ ・・・式１
ここで、［Ｐｒ］、［Ｓｍ］、［Ｅｕ］、［Ｇｄ］、［Ｔｂ］、［Ｄｙ］、［Ｈｏ］、［Ｅｒ］、［Ｔｍ］、［Ｙｂ］、［Ｌｕ］、［Ｓｃ］、［Ｏ］、［Ｎ］、及び［Ｓ］は、各元素の含有量［質量％］であり、元素を含有しない場合は０である。 By mass%,
C: 0.001 to 1.000%,
Si: 0.01-3.00%,
Mn: 0.10 to 4.50%,
P: 0.0005 to 0.300%,
S: 0.0300% or less,
Al: 0.001-5.000%,
N: 0.2000% or less,
O: 0.0100% or less,
Pr: 0 to 0.8000%, Sm: 0 to 0.8000%, Eu: 0 to 0.8000%, Gd: 0 to 0.8000%, Tb: 0 to 0.8000%, Dy: 0 to 0 .8000%, Ho: 0 to 0.8000%, Er: 0 to 0.8000%, Tm: 0 to 0.8000%, Yb: 0 to 0.8000%, Lu: 0 to 0.8000%, and Sc: At least one X element selected from the group consisting of 0 to 0.8000%,
Nb: 0-3.000%,
Ti: 0 to 0.500%,
Ta: 0 to 0.500%,
V: 0 to 1.00%,
Cu: 0 to 3.00%,
Ni: 0-60.00%,
Cr: 0 to 30.00%,
Mo: 0 to 5.00%,
W: 0 to 2.00%,
B: 0-0.0200%,
Co: 0 to 3.00%,
Be: 0 to 0.050%,
Ag: 0 to 0.500%,
Zr: 0 to 0.5000%,
Hf: 0 to 0.5000%,
Ca: 0-0.0500%,
Mg: 0-0.0500%,
At least one of La, Ce, Nd, Pm and Y: 0 to 0.5000% in total,
Sn: 0 to 0.300%,
Sb: 0 to 0.300%,
Te: 0 to 0.100%,
Se: 0 to 0.100%,
As: 0 to 0.050%,
Bi: 0 to 0.500%,
Pb: 0 to 0.500%, and the balance: Fe and impurities.
It has a chemical composition that satisfies the following formula 1 and has a chemical composition.
The phosphorus contained in the phosphide containing the X element, the amount of P contained in the phosphide measured by the extraction residue method is 0.0003 atomic% or more with respect to the steel material, and the phosphorus is measured by the TEM replica method. A steel material having an average particle size of a compound of less than 100 nm.
0.40 [Pr] +0.37 [Sm] +0.37 [Eu] +0.36 [Gd] +0.35 [Tb] +0.34 [Dy] +0.34 [Ho] +0.33 [Er] +0. 33 [Tm] +0.32 [Yb] +0.32 [Lu] +1.24 [Sc] -2.33 [O] -3.99 [N] -1.74 [S] ≧ 0.0003 ... Equation 1
Here, [Pr], [Sm], [Eu], [Gd], [Tb], [Dy], [Ho], [Er], [Tm], [Yb], [Lu], [Sc]. , [O], [N], and [S] are the content [mass%] of each element, and are 0 when the element is not contained. - 前記化学組成が、質量％で、
Ｎｂ：０．００３～３．０００％、
Ｔｉ：０．００５～０．５００％、
Ｔａ：０．００１～０．５００％、
Ｖ：０．００１～１．００％、
Ｃｕ：０．００１～３．００％、
Ｎｉ：０．００１～６０．００％、
Ｃｒ：０．００１～３０．００％、
Ｍｏ：０．００１～５．００％、
Ｗ：０．００１～２．００％、
Ｂ：０．０００１～０．０２００％、
Ｃｏ：０．００１～３．００％、
Ｂｅ：０．０００３～０．０５０％、及び
Ａｇ：０．００１～０．５００％
のうち１種又は２種以上を含む、請求項１に記載の鋼材。 The chemical composition is by mass%.
Nb: 0.003 to 3.000%,
Ti: 0.005 to 0.500%,
Ta: 0.001 to 0.500%,
V: 0.001 to 1.00%,
Cu: 0.001 to 3.00%,
Ni: 0.001 to 60.00%,
Cr: 0.001 to 30.00%,
Mo: 0.001 to 5.00%,
W: 0.001 to 2.00%,
B: 0.0001-0.0200%,
Co: 0.001 to 3.00%,
Be: 0.0003 to 0.050%, and Ag: 0.001 to 0.500%
The steel material according to claim 1, which comprises one or more of the above. - 前記化学組成が、質量％で、
Ｚｒ：０．０００１～０．５０００％、
Ｈｆ：０．０００１～０．５０００％、
Ｃａ：０．０００１～０．０５００％、
Ｍｇ：０．０００１～０．０５００％、並びに
Ｌａ、Ｃｅ、Ｎｄ、Ｐｍ及びＹの少なくとも１種：合計で０．０００１～０．５０００％
のうち１種又は２種以上を含む、請求項１又は２に記載の鋼材。 The chemical composition is by mass%.
Zr: 0.0001 to 0.5000%,
Hf: 0.0001 to 0.5000%,
Ca: 0.0001-0.0500%,
Mg: 0.0001 to 0.0500%, and at least one of La, Ce, Nd, Pm and Y: 0.0001 to 0.5000% in total.
The steel material according to claim 1 or 2, which comprises one or more of the above. - 前記化学組成が、質量％で、
Ｓｎ：０．００１～０．３００％、及び
Ｓｂ：０．００１～０．３００％
のうち１種又は２種を含む、請求項１～３のいずれか１項に記載の鋼材。 The chemical composition is by mass%.
Sn: 0.001 to 0.300%, and Sb: 0.001 to 0.300%
The steel material according to any one of claims 1 to 3, which comprises one or two of the above. - 前記化学組成が、質量％で、
Ｔｅ：０．００１～０．１００％、
Ｓｅ：０．００１～０．１００％、
Ａｓ：０．００１～０．０５０％、
Ｂｉ：０．００１～０．５００％、及び
Ｐｂ：０．００１～０．５００％
のうち１種又は２種以上を含む、請求項１～４のいずれか１項に記載の鋼材。 The chemical composition is by mass%.
Te: 0.001 to 0.100%,
Se: 0.001 to 0.100%,
As: 0.001 to 0.050%,
Bi: 0.001 to 0.500%, and Pb: 0.001 to 0.500%
The steel material according to any one of claims 1 to 4, which comprises one or more of the two or more.
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| JP2014173141A (en) * | 2013-03-08 | 2014-09-22 | Kobe Steel Ltd | High strength copper alloy |
| JP2018521221A (en) * | 2015-06-05 | 2018-08-02 | ポスコＰｏｓｃｏ | High-strength thin steel sheet with excellent drawability and bake hardenability, and method for producing the same |
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| WO2023053827A1 (en) * | 2021-09-28 | 2023-04-06 | 日本製鉄株式会社 | Steel plate |
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