FI124993B - Austeniittinen ruostumaton teräs - Google Patents
Austeniittinen ruostumaton teräs Download PDFInfo
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- FI124993B FI124993B FI20120319A FI20120319A FI124993B FI 124993 B FI124993 B FI 124993B FI 20120319 A FI20120319 A FI 20120319A FI 20120319 A FI20120319 A FI 20120319A FI 124993 B FI124993 B FI 124993B
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- 229910000963 austenitic stainless steel Inorganic materials 0.000 title claims description 46
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 50
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 38
- 229910000831 Steel Inorganic materials 0.000 claims description 31
- 239000010959 steel Substances 0.000 claims description 31
- 229910052759 nickel Inorganic materials 0.000 claims description 24
- 239000011651 chromium Substances 0.000 claims description 22
- 229910052757 nitrogen Inorganic materials 0.000 claims description 21
- 229910052804 chromium Inorganic materials 0.000 claims description 19
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 17
- 239000010949 copper Substances 0.000 claims description 16
- 239000011572 manganese Substances 0.000 claims description 15
- 229910052750 molybdenum Inorganic materials 0.000 claims description 15
- 229910052799 carbon Inorganic materials 0.000 claims description 14
- 238000005260 corrosion Methods 0.000 claims description 14
- 230000007797 corrosion Effects 0.000 claims description 14
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 13
- 229910052748 manganese Inorganic materials 0.000 claims description 13
- 239000011733 molybdenum Substances 0.000 claims description 13
- 229910052802 copper Inorganic materials 0.000 claims description 12
- 229910052710 silicon Inorganic materials 0.000 claims description 12
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 11
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 11
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 10
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 10
- 229910052796 boron Inorganic materials 0.000 claims description 10
- 239000010703 silicon Substances 0.000 claims description 10
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 9
- 239000010941 cobalt Substances 0.000 claims description 9
- 229910017052 cobalt Inorganic materials 0.000 claims description 9
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 9
- 239000012535 impurity Substances 0.000 claims description 6
- 229910001566 austenite Inorganic materials 0.000 description 15
- 229910001220 stainless steel Inorganic materials 0.000 description 8
- 229910000859 α-Fe Inorganic materials 0.000 description 8
- 229910000734 martensite Inorganic materials 0.000 description 7
- 238000005275 alloying Methods 0.000 description 6
- 239000003381 stabilizer Substances 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000012925 reference material Substances 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 238000007792 addition Methods 0.000 description 2
- 230000001627 detrimental effect Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229910052692 Dysprosium Inorganic materials 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000002939 deleterious effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000003467 diminishing effect Effects 0.000 description 1
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 description 1
- 238000007373 indentation Methods 0.000 description 1
- 239000000155 melt 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
- 150000004767 nitrides Chemical class 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
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- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
-
- 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
- C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
-
- 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
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- 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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- 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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/52—Ferrous alloys, e.g. steel alloys containing chromium with nickel with cobalt
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Description
AUSTENITIC STAINLESS STEEL
This invention relates to an austenitic stainless steel which has improved pitting corrosion resistance and improved strength with lower manufacturing costs than the standardized 316L /1.4404 type austenitic stainless steel.
The standardized 316L / 1.4404 austenitic stainless steel typically contains in weight % 0,01-0,03 % carbon, 0,25-0,75 % silicon, 1-2 % manganese, 16,8-17,8 % chromium, 10-10,5 % nickel, 2,0-2,3 % molybdenum, 0,2-0,64 % copper, 0,10-0,40 % cobalt, 0,03-0,07 % nitrogen and 0,002-0,0035 % boron, the rest being iron and inevitable impurities. The proof strength Rpo,2 for the standardized 316L / 1.4404 austenitic stainless steel is typically 220-230 MPa and respectively Rpi,o 260-270 MPa, while the tensile strength Rm is 520-530 MPa. Typical values for coil and sheet products having a 2B finish surface are RPo,2 290 MPa, Rp1i0 330 MPa and Rm 600 MPa. Because nickel and molybdenum are expensive elements and at least the price of nickel is volatile the manufacturing costs for the 316L /1.4404 type austenitic stainless steel are high.
It is known from the CN patent application 101724789 an austenitic stainless steel which contains in weight % less than 0,04 % carbon, 0,3-0,9 % silicon, 1-2 % manganese, 16-22 % chromium, 8-14 % nickel, less than 4 % molybdenum, 0,04-0,3 % nitrogen, 0,001-0,003 % boron and less than 0,3 % one or more of rare earth elements cerium (Ce), dysprosium (Dy), yttrium (Y) and neodymium (Nd), the rest being iron and inevitable impurities. The alloy of this CN patent application 101724789 is compared with 316L saying that the alloy has good mould toughness and improved yield strength, while plasticity and the pitting corrosion maintaining at the same level. However, the CN patent application 101724789 does not say anything about the manufacturing costs.
The JP patent application 2006-291296 relates to an austenitic stainless steel which contains in weight % less than 0,03 % carbon, less than 1,0 % silicon, less than 5 % manganese, 15-20 % chromium, 5-15 % nickel, less than 3 % molybdenum, less than 0,03 % nitrogen, 0,0001-0,01 % boron, and satisfies the Md30 temperature being between -60 °C and -10 °C and the SFI (Stacking-fault difficulty index) value > 30, which values are calculated using the formulas for Md30 = 551 -462(C+N)-9,2Si-8,1 Mn-29(Ni+Cu)-13,7Cr-18,5Mo and for SFI = 2,2Ni+6Cu-1,1Cr-13Si-1,2Mn+32. The JP patent application 2006-291296 mentions nickel as an expensive element, the maximum content being preferably 13 weight %.
The WO publication 2009/082501 describes an austenitic stainless steel which contains in weight % up to 0,08 % C, 3,0-6,0 % Mn, up to 2,0 % Si, 17,0-23,0 % Cr, 5,0-7,0 % Ni, 0,5-3,0 % Mo, up to 1,0 % Cu, 0,14-0.35 % N, up to 4,0 % W, up to 0,008 % B, up to 1,0 & Co, the rest being iron and incidental impurities. The WO publication 2011/053460 relates to a similar austenitic stainles steel containing in weight % up to 0,20 % C, 2,0 to 9,0 % Mn, up to 2,0 % Si, 15,0 to 23,0 % Cr, 1,0 to 9,5 % Ni, up to 3,0 % Mo, up to 3,0 % Cu, 0,05 to 0,35 % N, (7,5(% C) < (% Nb + % Ti + % V + % Ta + % Zr) < 1,5, the rest being iron and incidental impurities. These austenitic stainless steels contain manganese more than 2 weight % which is not typical for austentic stainless steels of the 300 series. This high manganese content also causes problems in the circulation of steel scrap because the circulated steel having high manganese content does not maintain the value in the pricing of raw material.
The object of the present invention is to eliminate some drawbacks of the prior art and to achieve an improved austenitic stainless steel which manufacturing costs are cheaper because high price elements are partly substituted by low price elements without diminishing and more like improving the properties, such as pitting corrosion resistance and strength. The essential features of the present invention are enlisted in the appended claims.
The present invention relates to an austenitic stainless steel which contains in weight % less than 0,03 % carbon (C), 0,2 - 0,6 % silicon (Si), 1,0 - 2,0 % manganese (Μη), 19,0 - 21,0 % chromium (Cr), 7,5 - 9,5 % nickel (Ni), 0,4 - 1,4 % molybdenum (Mo), less than 1,0 % copper (Cu), 0,10 - 0,25 % nitrogen (N), optionally less than 1,0 % cobalt, optionally less than 0,006 % boron (B), and the rest being iron (Fe) and inevitable impurities.
When comparing the austenitic stainless steel of the invention with the 316L / 1.4404 type austenitic stainless steel, the chromium content according to the invention is higher at least partly substituting molybdenum as well as the nitrogen content is higher at least partly substituting molybdenum as well as nickel. In spite of these substitutions the Creq/Nieq ratio between the chromium equivalent and the nickel equivalent is kept essentially at the similar or lower level when compared to the Creq/Nieq ratio in the reference 316L / 1.4404 type austenitic stainless steel. The delta ferrite (δ-ferrite) content is kept between 2 -9 % after high temperature annealing and fast cooling as well as in a solidification structure after welding. This feature diminishes problems related to hot working and welding i.e. hot cracking. The proof strength Rp0,2 for the austenitic stainless steel in accordance with the invention is typically 320 - 450 MPa and respectively Rpi,o370 - 500 MPa, while the tensile strength Rm is 630 -800 MPa. Thus the strength values are about 70 - 170 MPa higher than the strength of the 316L / 1.4404 type austenitic stainless steel. Further, the austenitic stainless steel of the invention has the PREN value greater than 24, and the Creq/Nieq ratio in the steel is less than 1,60 as well as the steel has Md3o value less than -80 °C.
The effects and the contents in weight % of the elements for the austenitic stainless steel of the invention are described in the following:
Carbon (C) is a valuable austenite forming and austenite stabilizing element. Carbon can be added up to 0,03 % but higher levels have detrimental influence on corrosion resistance. The carbon content shall not be less than 0,01 %. Limiting the carbon content to low levels carbon also increases the need for other expensive austenite formers and austenite stabilizers.
Silicon (Si) is added to stainless steels for deoxidizing purposes in the melt shop and should not be below 0,2 % preferably at least 0,25 %. Silicon is a ferrite forming element, but silicon has a stronger stabilizing effect on austenite stability against martensite formation. The silicon content must be limited below 0,6 %, preferably below 0,55 %.
Manganese (Mn) is an important additive to ensure the stable austenitic crystal structure, also against martensite deformation. Manganese also increases the solubility of nitrogen to the steel. However, too high manganese contents will reduce the corrosion resistance and hot workability. Therefore, the manganese content shall be at the range of 1,0-2,0 %, preferably 1,6 - 2,0 %.
Chromium (Cr) is responsible of ensuring corrosion resistance of the stainless steel. Chromium is a ferrite forming element, but chromium is also the main addition to create a proper phase balance between austenite and ferrite. Increasing the chromium content increases the need for expensive austenite formers nickel, manganese or necessitates impractically high carbon and nitrogen contents. Higher chromium content also increases beneficial nitrogen solubility to austenitic phase. Therefore, the chromium content shall be in the range 19-21 %, preferably 19,5 - 20,5 %.
Nickel (Ni) is a strong austenite stabilizer and enhances formability and toughness. However, nickel is an expensive element, and therefore, in order to maintain cost-efficiency of the invented steel the upper limit for the nickel alloying shall be 9,5 %, preferably 9,0 %. Having a large influence on austenite stability against martensite formation nickel has to be present in a narrow range. The lower limit for the nickel content is thus 7,5 %, preferably 8,0 %.
Copper (Cu) can be used as a cheaper substitute for nickel as austenite former and austenite stabilizer. Copper is a weak stabilizer of the austenite phase but has a strong effect on the resistance to martensite formation. Copper improves formability by reducing stacking fault energy and improves corrosion resistance in certain environments. If copper content is higher than 3,0% it reduces hot workability. In this invention the copper content range is 0,2 - 1,0 %, preferably 0,3 - 0,6 %.
Cobalt (Co) stabilizes austenite and is a substitute for nickel. Cobalt also increases the strength. Cobalt is very expensive and therefore its use is limited. If cobalt is added, the maximum limit is 1,0 %, preferably less than 0,4 %, and the range is preferably 0,1 - 0,3 %, when cobalt naturally comes from recycled scrap and/or with nickel alloying.
Nitrogen (N) is a strong austenite former and stabilizer. Therefore, nitrogen alloying improves the cost efficiency of the invented steel by enabling lower use of nickel, copper and manganese. Nitrogen improves pitting corrosion resistance very effectively, especially when alloyed together with molybdenum. In order to ensure reasonably low use of the above-mentioned alloying elements, nitrogen content shall be at least 0,1 %. High nitrogen contents increase the strength of the steel and thus make forming operations more difficult. Furthermore, risk of nitride precipitation increases with increasing nitrogen content. For these reasons, the nitrogen content shall not exceed 0,25 %, and the content is preferably at the range of 0,13 - 0,20 %.
Molybdenum (Mo) is an element, which improves the corrosion resistance of the steel by modifying the passive film. Molybdenum increases the resistance to martensite formation. Lower molybdenum content decreases the likelihood of intermetallic phases such as sigma to form when steel is exposed to high temperatures. High Mo levels (> 3,0 %) decrease the hot workability and can increase delta ferrite (δ-ferrite) solidification to detrimental level. However, due to the high cost, the Mo content of the steel shall be at the range of 0,4 - 1,4 % preferably 0,5 - 1,0 %.
Boron (B) can be used for improved hot workability and better surface quality. The boron additions of more than 0,01 % can be deleterious for workability and corrosion resistance of the steel. The austenitic stainless steel presented in this invention has boron optionally less than 0,006 %, preferably less than 0,004 %.
The properties of the austenitic stainless steel in accordance with the invention were tested with the chemical compositions of the table 1 for alloys A, B, C, D, E, F, G, H and I. The table 1 also contains the chemical composition of the 316L / 1.4404 (316L) type austenitic stainless steel which was used as a reference.
For the chemical compositions A, B, C, D, E, F, G, H, I and 316L of the table 1 the chromium equivalent (Creq) and the nickel equivalent (Nieq) were calculated using the following formulas (1) and (2):
The predicted Md3o temperature (Md3o) for the each steel of the table 1 was calculated using Nohara expression (3)
established for austenitic stainless steels when annealed at the temperature of 1050 °C. The Md30-temperature is defined as the temperature at which 0,3 true strain yields 50% transformation of the austenite to martensite.
The pitting resistance equivalent number (PREN) is calculated using the formula (4):
The results for the chromium equivalent (Creq), the nickel equivalent (Nieq), the ratio Creq/Nieq, the Md3o temperature (Md30) and the pitting resistance equivalent number (PREN) are presented in the table 2.
The results of the table 2 show that the pitting resistance equivalent number (PREN) is higher, at the range of 27,0 - 29,5, for the austenitic stainless steel of the invention than for the reference stainless steel 316L (25,1). The ratio Creq/Nieq at the range of 1,20 - 1,45 is lesser for steels A - I of the invention than for the reference stainless steel 316L (1,50), indicating that the coefficient of nitrogen in nickel equivalent has strong effect on phase balance and can therefore be very useful for affordable alloying. The Md30 temperature is lower than -100,1 °C for each austenitic stainless steel of the invention in the table 2 and also lower than the Md3o temperature for the reference steel 316L and thus austenite stability against martensite transformation in the austenitic stainless steel of the invention is improved.
The measured ferrite contents in the cold rolled and annealed condition for the steel A - I are presented in table 3 which shows that the steel of the invention and the reference 316L austenitic stainless steel have essentially the equal amount of ferrite in the final microstructure.
Table 3 * minimum detection limit for measuring device was 0,10 %
The proof strengths Rp0,2 and Rp1i0 as well as the tensile strength Rm for the austenitic stainless steels A - I according to the invention were determined and are presented in the table 4 with the respective values of the standardized 316L austenitic stainless steel as a reference.
As shown in the table 4 the determined strengths for the austenitic stainless steel of the invention are about 70 - 170 MPa higher than the respective strengths for the reference 316L austenitic stainless steel. Further, the austenitic stainless steel in accordance with the invention is essentially easily rolled in temper rolling conditions.
Austenitic stainless steel presented in this invention has same level of formability as reference material 316L even though the strength is notably higher. Formability test results are presented in table 5 and there is LDR (Limiting Drawing Ratio) and Erichsen Index. The limiting drawing ratio is defined as a ratio of the maximum blank diameter that can be safely drawn into a cup without flange to the punch diameter. LDR is determined with 50 mm flat head punch and 25 kN holding force. The Erichsen cupping test is a ductility test, which is employed to evaluate the ability of metallic sheets and strips to undergo plastic deformation in stretch forming. The test consists of forming an indentation by pressing a punch with a spherical end against a test piece clamped between a blank holder and a die, until a through crack appears. The depth of the cup is measured. Erichsen Index is an average value of 5 tests.
Nitrogen alloying with high chromium content and lowered molybdenum content in austenitic stainless steel presented in this invention yields remarkably higher pitting corrosion resistance when compared to reference material 316L. Results are presented in table 6. The pitting corrosion tests were done to ground specimen surface with Avesta cell in 1M NaCI solution at 35 °C temperature.
The results in the table 6 show that the breakdown potential i.e. the lowest potential when pitting corrosion occurs, is much higher for the austenitic stainless steel (Steels A -1) of the invention than for reference material 316L.
Claims (13)
1. Austeniittinen ruostumaton teräs, jolla on parannettu pistekorroosiokestävyys ja parannettu lujuus, tunnettu siitä, että teräs sisältää paino-%:na vähemmän kuin 0,03 % hiiltä (C), 0,2 - 0,6 % piitä (Si), 1,0 - 2,0 % mangaania (Mn), 19,0 - 21,0 % kromia (Cr), 7,5 - 9,5 % nikkeliä (Ni), 0,4 - 1,4 % molybdeeniä (Mo), vähemmän kuin 1,0 % kuparia (Cu), 0,10 - 0,25 % typpeä (N), valinnaisesti vähemmän kuin 1,0 % kobolttia (Co), valinnaisesti vähemmän kuin 0,006 % booria (B), lopun ollessa rautaa (Fe) ja väistämättömiä epäpuhtauksia, ja että myötölujuus Rp0,2 on 320 - 450 MPa ja myötölujuus Rpi,0 370 - 500 MPa, ja murtolujuus Rm on 630 - 800 MPa.
2. Patenttivaatimuksen 1 mukainen austeniittinen ruostumaton teräs, tunnettu siitä, että teräs sisältää 0,25 - 0,55 paino-% piitä.
3. Patenttivaatimuksen 1 tai 2 mukainen austeniittinen ruostumaton teräs, tunnettu siitä, että teräs sisältää 1,6 - 2,0 paino-% mangaania.
4. Jonkin edellä olevan patenttivaatimuksen mukainen austeniittinen ruostumaton teräs, tunnettu siitä, että teräs sisältää 19,5 - 20,5 paino-% kromia.
5. Jonkin edellä olevan patenttivaatimuksen mukainen austeniittinen ruostumaton teräs, tunnettu siitä, että teräs sisältää 8,0 - 9,0 paino-% nikkeliä.
6. Jonkin edellä olevan patenttivaatimuksen mukainen austeniittinen ruostumaton teräs, tunnettu siitä, että teräs sisältää 0,5 - 1,0 paino-% molybdeeniä.
7. Jonkin edellä olevan patenttivaatimuksen mukainen austeniittinen ruostumaton teräs, tunnettu siitä, että teräs sisältää 0,3 - 0,6 paino-% kuparia.
8. Jonkin edellä olevan patenttivaatimuksen mukainen austeniittinen ruostumaton teräs, tunnettu siitä, että teräs sisältää 0,13 - 0,20 paino-% typpeä.
9. Jonkin edellä olevan patenttivaatimuksen mukainen austeniittinen ruostumaton teräs, tunnettu siitä, että teräs sisältää vähemmän kuin 0,4 painoko kobolttia.
10. Jonkin edellä olevan patenttivaatimuksen mukainen austeniittinen ruostumaton teräs, tunnettu siitä, että teräs sisältää vähemmän kuin 0,004 paino-% booria.
11. Jonkin edellä olevan patenttivaatimuksen mukainen austeniittinen ruostumaton teräs, tunnettu siitä, että teräksen PREN-arvo on suurempi kuin 24.
12. Jonkin edellä olevan patenttivaatimuksen mukainen austeniittinen ruostumaton teräs, tunnettu siitä, että teräksen Creq/Nieq -suhde on vähemmän kuin 1,60.
13. Jonkin edellä olevan patenttivaatimuksen mukainen austeniittinen ruostumaton teräs, tunnettu siitä, että teräksen Md3o -arvo on vähemmän kuin -80 °C.
Priority Applications (18)
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| FI20120319A FI124993B (fi) | 2012-09-27 | 2012-09-27 | Austeniittinen ruostumaton teräs |
| BR112015006759-0A BR112015006759B1 (pt) | 2012-09-27 | 2013-09-26 | Aço inoxidável austenítico |
| MYPI2015700949A MY174110A (en) | 2012-09-27 | 2013-09-26 | Austenitic stainless steel |
| PCT/FI2013/050940 WO2014049209A1 (en) | 2012-09-27 | 2013-09-26 | Austenitic stainless steel |
| SI201330602A SI2900840T1 (sl) | 2012-09-27 | 2013-09-26 | Austenitno nerjavno jeklo |
| KR1020157010432A KR20150055073A (ko) | 2012-09-27 | 2013-09-26 | 오스테나이트 스테인레스 스틸 |
| EP13842730.7A EP2900840B1 (en) | 2012-09-27 | 2013-09-26 | Austenitic stainless steel |
| CN201380056592.2A CN105247091A (zh) | 2012-09-27 | 2013-09-26 | 奥氏体不锈钢 |
| ES13842730.7T ES2627264T3 (es) | 2012-09-27 | 2013-09-26 | Acero inoxidable austenítico |
| JP2015533650A JP6096907B2 (ja) | 2012-09-27 | 2013-09-26 | オーステナイト系ステンレス鋼 |
| KR1020157030840A KR101735991B1 (ko) | 2012-09-27 | 2013-09-26 | 오스테나이트 스테인레스 스틸 |
| AU2013322512A AU2013322512B2 (en) | 2012-09-27 | 2013-09-26 | Austenitic stainless steel |
| EA201590434A EA028895B1 (ru) | 2012-09-27 | 2013-09-26 | Аустенитная нержавеющая сталь |
| US14/431,048 US9771641B2 (en) | 2012-09-27 | 2013-09-26 | Austenitic stainless steel |
| CA2885705A CA2885705C (en) | 2012-09-27 | 2013-09-26 | Austenitic stainless steel |
| MX2015003848A MX366986B (es) | 2012-09-27 | 2013-09-26 | Acero inoxidable austenitico. |
| CN201910070342.3A CN109913747A (zh) | 2012-09-27 | 2013-09-26 | 奥氏体不锈钢 |
| TW102135270A TWI628296B (zh) | 2012-09-27 | 2013-09-27 | 沃斯田鐵系不鏽鋼 |
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| FI20120319 | 2012-09-27 | ||
| FI20120319A FI124993B (fi) | 2012-09-27 | 2012-09-27 | Austeniittinen ruostumaton teräs |
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| FI20120319A7 FI20120319A7 (fi) | 2014-03-28 |
| FI124993B true FI124993B (fi) | 2015-04-15 |
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| FI20120319A FI124993B (fi) | 2012-09-27 | 2012-09-27 | Austeniittinen ruostumaton teräs |
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| EP (1) | EP2900840B1 (fi) |
| JP (1) | JP6096907B2 (fi) |
| KR (2) | KR101735991B1 (fi) |
| CN (2) | CN109913747A (fi) |
| AU (1) | AU2013322512B2 (fi) |
| BR (1) | BR112015006759B1 (fi) |
| CA (1) | CA2885705C (fi) |
| EA (1) | EA028895B1 (fi) |
| ES (1) | ES2627264T3 (fi) |
| FI (1) | FI124993B (fi) |
| MX (1) | MX366986B (fi) |
| MY (1) | MY174110A (fi) |
| SI (1) | SI2900840T1 (fi) |
| TW (1) | TWI628296B (fi) |
| WO (1) | WO2014049209A1 (fi) |
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| KR101773603B1 (ko) * | 2016-01-08 | 2017-08-31 | (주)부경대학교 기술지주회사 | 스테인레스 스틸과 알루미늄 또는 그 합금을 포함하는 경량 복합재료의 제조방법 및 이에 의해 제조된 경량 복합재료 |
| CN106011677A (zh) * | 2016-06-13 | 2016-10-12 | 苏州双金实业有限公司 | 一种能够有效防止冲击的钢 |
| KR101952808B1 (ko) * | 2017-08-22 | 2019-02-28 | 주식회사포스코 | 열간가공성 및 내수소취성이 우수한 저Ni 오스테나이트계 스테인리스강 |
| US11339461B2 (en) * | 2017-10-03 | 2022-05-24 | Nippon Steel Corporation | Austenitic stainless steel |
| CA3078322A1 (en) * | 2017-10-03 | 2019-04-11 | Nippon Steel Corporation | Austenitic stainless steel weld metal and welded structure |
| CN108396223B (zh) * | 2018-03-29 | 2020-09-29 | 东北大学 | 一种超级奥氏体不锈钢及其合金成分优化设计方法 |
| ES2938462T3 (es) * | 2018-09-04 | 2023-04-11 | Ford Global Tech Llc | Disco de freno y procedimiento para producir el mismo |
| CN109504827A (zh) * | 2018-12-22 | 2019-03-22 | 中南大学 | 一种含铜钽钴高耐蚀不锈钢及其加工与热处理方法 |
| CN109504832A (zh) * | 2018-12-22 | 2019-03-22 | 中南大学 | 一种铜锆抗蚀增强奥氏体不锈钢及其制备方法 |
| CN109504830A (zh) * | 2018-12-22 | 2019-03-22 | 中南大学 | 一种铜铌抗蚀奥氏体不锈钢及其制备方法 |
| CN109355469A (zh) * | 2018-12-22 | 2019-02-19 | 中南大学 | 一种铜钒钴抗蚀奥氏体不锈钢及其加工与热处理方法 |
| CN109355594B (zh) * | 2018-12-22 | 2022-04-01 | 佛山培根细胞新材料有限公司 | 一种铜钒钴改性不锈钢及其加工与热处理方法 |
| CN110000389B (zh) * | 2019-03-14 | 2020-07-31 | 全亿大科技（佛山）有限公司 | 不锈钢的制备方法 |
| KR102463015B1 (ko) * | 2020-11-23 | 2022-11-03 | 주식회사 포스코 | 열간가공성이 우수한 고강도 오스테나이트계 스테인리스강 |
| JP7765692B2 (ja) * | 2020-12-14 | 2025-11-07 | 日本製鉄株式会社 | オーステナイト系ステンレス鋼及び耐食性部材 |
| KR102570524B1 (ko) * | 2020-12-21 | 2023-08-24 | 주식회사 포스코 | 내식성과 절삭성이 향상된 오스테나이트계 스테인리스강 및 그 제조방법 |
| CN112553533B (zh) * | 2020-12-25 | 2022-05-10 | 宝钢德盛不锈钢有限公司 | 一种经济性高强度奥氏体不锈钢 |
| JP2022181633A (ja) * | 2021-05-26 | 2022-12-08 | 日鉄ステンレス株式会社 | オーステナイト系ステンレス鋼材及びその製造方法、並びに加工製品 |
| CN114318144A (zh) * | 2021-12-24 | 2022-04-12 | 浦项(张家港)不锈钢股份有限公司 | 一种螺旋焊管用途的奥氏体不锈钢、制造工艺及用途 |
| CN115821153A (zh) * | 2022-06-27 | 2023-03-21 | 浙江吉森金属科技有限公司 | 一种温度传感器外壳用不锈钢及其制造方法 |
| KR102556317B1 (ko) * | 2022-08-12 | 2023-07-18 | 주식회사 에이티에스 | 플라즈마 에칭 장비용 합금 및 이를 포함하는 체결기구 |
| CN118086795A (zh) * | 2024-03-13 | 2024-05-28 | 浙江巨创不锈钢制品科技有限公司 | 用于低温环境的耐腐蚀超软不锈钢及制备方法 |
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- 2013-09-26 EA EA201590434A patent/EA028895B1/ru not_active IP Right Cessation
- 2013-09-26 EP EP13842730.7A patent/EP2900840B1/en active Active
- 2013-09-26 BR BR112015006759-0A patent/BR112015006759B1/pt active IP Right Grant
- 2013-09-26 US US14/431,048 patent/US9771641B2/en active Active
- 2013-09-26 WO PCT/FI2013/050940 patent/WO2014049209A1/en not_active Ceased
- 2013-09-26 MY MYPI2015700949A patent/MY174110A/en unknown
- 2013-09-26 AU AU2013322512A patent/AU2013322512B2/en active Active
- 2013-09-26 CN CN201910070342.3A patent/CN109913747A/zh active Pending
- 2013-09-26 SI SI201330602A patent/SI2900840T1/sl unknown
- 2013-09-26 ES ES13842730.7T patent/ES2627264T3/es active Active
- 2013-09-26 KR KR1020157030840A patent/KR101735991B1/ko active Active
- 2013-09-26 JP JP2015533650A patent/JP6096907B2/ja active Active
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Also Published As
| Publication number | Publication date |
|---|---|
| CN109913747A (zh) | 2019-06-21 |
| CN105247091A (zh) | 2016-01-13 |
| MY174110A (en) | 2020-03-10 |
| SI2900840T1 (sl) | 2017-05-31 |
| EP2900840B1 (en) | 2017-03-01 |
| TW201420775A (zh) | 2014-06-01 |
| CA2885705C (en) | 2021-06-01 |
| BR112015006759B1 (pt) | 2019-07-02 |
| KR20150125733A (ko) | 2015-11-09 |
| MX366986B (es) | 2019-08-01 |
| KR101735991B1 (ko) | 2017-05-15 |
| EA201590434A1 (ru) | 2015-09-30 |
| AU2013322512A1 (en) | 2015-04-09 |
| ES2627264T3 (es) | 2017-07-27 |
| MX2015003848A (es) | 2015-07-17 |
| KR20150055073A (ko) | 2015-05-20 |
| EP2900840A4 (en) | 2016-04-06 |
| JP6096907B2 (ja) | 2017-03-15 |
| TWI628296B (zh) | 2018-07-01 |
| WO2014049209A1 (en) | 2014-04-03 |
| JP2015532364A (ja) | 2015-11-09 |
| CA2885705A1 (en) | 2014-04-03 |
| US20150247228A1 (en) | 2015-09-03 |
| EP2900840A1 (en) | 2015-08-05 |
| US9771641B2 (en) | 2017-09-26 |
| EA028895B1 (ru) | 2018-01-31 |
| FI20120319A7 (fi) | 2014-03-28 |
| BR112015006759A2 (pt) | 2017-07-04 |
| AU2013322512B2 (en) | 2017-12-07 |
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