JP2024500152A - Wire rods and parts with improved delayed fracture resistance and their manufacturing method - Google Patents
Wire rods and parts with improved delayed fracture resistance and their manufacturing method Download PDFInfo
- Publication number
- JP2024500152A JP2024500152A JP2023537438A JP2023537438A JP2024500152A JP 2024500152 A JP2024500152 A JP 2024500152A JP 2023537438 A JP2023537438 A JP 2023537438A JP 2023537438 A JP2023537438 A JP 2023537438A JP 2024500152 A JP2024500152 A JP 2024500152A
- Authority
- JP
- Japan
- Prior art keywords
- relational expression
- delayed fracture
- fracture resistance
- content
- less
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000003111 delayed effect Effects 0.000 title claims abstract description 68
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 16
- 230000014509 gene expression Effects 0.000 claims abstract description 46
- 238000000034 method Methods 0.000 claims abstract description 13
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 12
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 12
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 12
- 239000012535 impurity Substances 0.000 claims abstract description 11
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 11
- 229910052796 boron Inorganic materials 0.000 claims abstract description 10
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 10
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 8
- 229910000831 Steel Inorganic materials 0.000 claims description 27
- 239000010959 steel Substances 0.000 claims description 27
- 229910001566 austenite Inorganic materials 0.000 claims description 24
- 238000010438 heat treatment Methods 0.000 claims description 22
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 13
- 230000000717 retained effect Effects 0.000 claims description 12
- 229910000734 martensite Inorganic materials 0.000 claims description 10
- 238000010791 quenching Methods 0.000 claims description 10
- 230000000171 quenching effect Effects 0.000 claims description 10
- 238000005096 rolling process Methods 0.000 claims description 8
- 238000005496 tempering Methods 0.000 claims description 8
- 229910052799 carbon Inorganic materials 0.000 claims description 5
- 229910052742 iron Inorganic materials 0.000 claims description 5
- 238000004804 winding Methods 0.000 claims description 3
- 238000010586 diagram Methods 0.000 abstract 1
- 239000011572 manganese Substances 0.000 description 29
- 239000010936 titanium Substances 0.000 description 28
- 238000005728 strengthening Methods 0.000 description 19
- 230000000052 comparative effect Effects 0.000 description 17
- 230000000694 effects Effects 0.000 description 15
- 239000006104 solid solution Substances 0.000 description 15
- 239000013078 crystal Substances 0.000 description 14
- 239000000047 product Substances 0.000 description 12
- 229910045601 alloy Inorganic materials 0.000 description 7
- 239000000956 alloy Substances 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 7
- 239000000203 mixture Substances 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 238000000465 moulding Methods 0.000 description 4
- 239000002244 precipitate Substances 0.000 description 4
- 229910000859 α-Fe Inorganic materials 0.000 description 4
- 230000006866 deterioration Effects 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 239000003507 refrigerant Substances 0.000 description 2
- 238000005482 strain hardening Methods 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- KZEVSDGEBAJOTK-UHFFFAOYSA-N 1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-2-[5-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]-1,3,4-oxadiazol-2-yl]ethanone Chemical compound N1N=NC=2CN(CCC=21)C(CC=1OC(=NN=1)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)=O KZEVSDGEBAJOTK-UHFFFAOYSA-N 0.000 description 1
- YJLUBHOZZTYQIP-UHFFFAOYSA-N 2-[5-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]-1,3,4-oxadiazol-2-yl]-1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethanone Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C1=NN=C(O1)CC(=O)N1CC2=C(CC1)NN=N2 YJLUBHOZZTYQIP-UHFFFAOYSA-N 0.000 description 1
- APLNAFMUEHKRLM-UHFFFAOYSA-N 2-[5-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]-1,3,4-oxadiazol-2-yl]-1-(3,4,6,7-tetrahydroimidazo[4,5-c]pyridin-5-yl)ethanone Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C1=NN=C(O1)CC(=O)N1CC2=C(CC1)N=CN2 APLNAFMUEHKRLM-UHFFFAOYSA-N 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 229910001182 Mo alloy Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000013100 final test Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 230000002706 hydrostatic effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000011159 matrix material Substances 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
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910001562 pearlite Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000005491 wire drawing Methods 0.000 description 1
Images
Classifications
-
- 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
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/25—Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten")
-
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
- C21D1/32—Soft annealing, e.g. spheroidising
-
- 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
- C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
- C21D8/065—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires of ferrous alloys
-
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0093—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for screws; for bolts
-
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
-
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
- C21D9/525—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length for wire, for rods
-
- 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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- 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
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
-
- 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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/001—Austenite
-
- 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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
Abstract
【課題】本発明の目的は、遅れ破壊抵抗性が向上した線材、部品およびその製造方法を提供することである。【解決手段】本発明による遅れ破壊抵抗性が向上した線材は、重量％で、Ｃ：０．１５～０．３０％、Ｓｉ：０．１５～０．２５％、Ｍｎ：０．９５～１．３５％、Ｐ：０．０３０％以下、Ｓ：０．０３０％以下、Ｔｉ：０．０１５～０．０３０％、Ｂ：０．００１０～０．００４０％、Ｎ：０．００１０～０．００８０％を含み、残部がＦｅおよび不可避な不純物からなり、下記関係式１を満たすことを特徴とする。［関係式１］２．０≦５．５×［Ｓｉ］＋［Ｍｎ］≦２．４（関係式１中、［Ｓｉ］および［Ｍｎ］それぞれは、当該元素の含有量（重量％）を意味する）【選択図】図１An object of the present invention is to provide a wire rod, a component, and a method for manufacturing the same, which have improved delayed fracture resistance. [Solution] The wire rod with improved delayed fracture resistance according to the present invention has C: 0.15 to 0.30%, Si: 0.15 to 0.25%, and Mn: 0.95 to 1 in weight percent. .35%, P: 0.030% or less, S: 0.030% or less, Ti: 0.015-0.030%, B: 0.0010-0.0040%, N: 0.0010-0. 0080%, the remainder being Fe and unavoidable impurities, and satisfying the following relational expression 1. [Relational Expression 1] 2.0≦5.5×[Si]+[Mn]≦2.4 (In Relational Expression 1, [Si] and [Mn] each represent the content (wt%) of the element concerned. Meaning) [Selection diagram] Figure 1
Description
本発明は、遅れ破壊抵抗性が向上した線材、部品およびその製造方法に係り、より詳細には、多様な応力および腐食環境に露出する自動車、構造物の締結用ボルトなどに使用できる線材、部品およびその製造方法に関する。 The present invention relates to wire rods and parts with improved delayed fracture resistance, and a method for manufacturing the same, and more particularly, the present invention relates to wire rods and parts that can be used for fastening bolts of automobiles and structures exposed to various stress and corrosive environments. and its manufacturing method.
自動車、構造物の締結用ボルトなどの素材に使用される線材は、自動車の軽量化および構造物の小型化に伴い、高強度化が要求されている。一般的に、鋼材の強度増加のためには、金属の強化機構である冷間加工、結晶粒微細化、マルテンサイト強化および析出強化などを活用する。 Wire rods used as materials for fastening bolts for automobiles and structures are required to have higher strength as automobiles become lighter and structures become smaller. Generally, to increase the strength of steel materials, metal strengthening mechanisms such as cold working, grain refinement, martensitic strengthening, and precipitation strengthening are utilized.
しかしながら、このような強化機構として活用された冷間加工、結晶粒界、マルテンサイトラス（ｌａｔｈ）境界および微細析出物境界などは、鋼材内水素のトラップ部として作用し、また、遅れ破壊を劣化させる原因として作用する。このような理由で、引張強度１ＧＰａ以上の高強度ボルトでは、遅れ破壊が劣化する問題がある。 However, cold working, grain boundaries, martensite lath boundaries, fine precipitate boundaries, etc. that are utilized as such strengthening mechanisms act as traps for hydrogen within the steel material, and also deteriorate delayed fracture. Act as a cause. For this reason, high-strength bolts with a tensile strength of 1 GPa or more have a problem of delayed fracture.
このような問題を解決するために、従来、焼き戻しマルテンサイト（Ｔｅｍｐｅｒｅｄ Ｍａｒｔｅｎｓｉｔｅ）組織を有する１ＧＰａ以上のボルト用鋼材は、Ｍｏを添加したＣｒ－Ｍｏ合金鋼を使用していたが、ボルト製造工程技術の発展によるコスト低減ニーズに対応するためにＣｒ－Ｍｏ鋼をＣｒ－Ｂ鋼に置き換えようとする試みがあった。その結果、安全に大きな影響がない構造物に使用されるボルトからＣｒ－Ｂ鋼を活用してコスト低減を具現し、その安全性を確認した後、自動車の一部締結用ボルトにもＣｒ－Ｂ鋼が適用されている。 In order to solve these problems, conventionally, Cr-Mo alloy steel with Mo added was used for bolt steel materials with a tempered martensite structure of 1 GPa or higher, but the bolt manufacturing process There have been attempts to replace Cr--Mo steel with Cr--B steel in order to meet the need for cost reduction due to technological development. As a result, we realized cost reduction by using Cr-B steel for bolts used in structures that do not have a major impact on safety, and after confirming its safety, we also used Cr-B steel for some fastening bolts in automobiles. B steel is used.
ひいては、自動車業界では、極限までのコスト低減のためにＣｒ－Ｂ鋼よりさらにコスト低減が可能なボルト用素材を開発するためのニーズがある。このようなニーズに対応するために、最近では、Ｃｒに比べて安価なＭｎを活用するＭｎ－Ｂ鋼を１ＧＰａ以上の高強度ボルト用素材に適用するための技術開発が行われている。 Furthermore, in the automobile industry, there is a need to develop a material for bolts that can be even more cost-reduced than Cr-B steel in order to reduce costs to the utmost. In order to meet such needs, technology has recently been developed to apply Mn-B steel, which utilizes Mn, which is cheaper than Cr, as a material for high-strength bolts of 1 GPa or more.
しかしながら、Ｍｎは、Ｃｒに比べてフェライト基地内に高い固溶強化を誘発するので、Ｍｎ－Ｂの鋼は、ボルトの製造時にボルトのねじ部にクラックが発生することがある。したがって、１ＧＰａ以上の高強度ボルトを製造するために添加されるＭｎの含有量が高い鋼は、ボルトねじ部のクラックによって遅れ破壊が発生しうる短所があり、高強度ボルトに適用するのには問題がある。 However, since Mn induces higher solid solution strengthening in the ferrite base than Cr, cracks may occur in the threaded portion of the bolt when Mn-B steel is manufactured. Therefore, steel with a high content of Mn, which is added to produce high-strength bolts of 1 GPa or more, has the disadvantage of causing delayed fracture due to cracks in the bolt threads, and is therefore not suitable for use in high-strength bolts. There's a problem.
本発明の目的とするところは、合金元素の制御を通じて、Ｍｎ－Ｂ鋼の固溶強化効果を最適化し、成形性を向上させることによって、遅れ破壊抵抗性が向上した高強度ボルト用線材、ボルトおよびその製造方法を提供しようとするものである。 The purpose of the present invention is to optimize the solid solution strengthening effect of Mn-B steel through control of alloying elements and improve formability, thereby providing wire rods for high-strength bolts with improved delayed fracture resistance. and its manufacturing method.
本発明の遅れ破壊抵抗性が向上した線材は、重量％で、Ｃ：０．１５～０．３０％、Ｓｉ：０．１５～０．２５％、Ｍｎ：０．９５～１．３５％、Ｐ：０．０３０％以下、Ｓ：０．０３０％以下、Ｔｉ：０．０１５～０．０３０％、Ｂ：０．００１０～０．００４０％、Ｎ：０．００１０～０．００８０％を含み、残部がＦｅおよび不可避な不純物からなり、下記関係式１を満たすことを特徴とする。
［関係式１］２．０≦５．５×［Ｓｉ］＋［Ｍｎ］≦２．４
（関係式１中、［Ｓｉ］および［Ｍｎ］それぞれは、当該元素の含有量（重量％）を意味する）
The wire rod with improved delayed fracture resistance of the present invention has, in weight percent, C: 0.15 to 0.30%, Si: 0.15 to 0.25%, Mn: 0.95 to 1.35%, Contains P: 0.030% or less, S: 0.030% or less, Ti: 0.015 to 0.030%, B: 0.0010 to 0.0040%, N: 0.0010 to 0.0080%. , the remainder consists of Fe and unavoidable impurities, and the following
[Relational expression 1] 2.0≦5.5×[Si]+[Mn]≦2.4
(In
また、下記関係式２を満たすことができる。
［関係式２］１．０＜［Ｔｉ］／３．４２［Ｎ］＜２．０
（関係式２中、［Ｔｉ］および［Ｎ］それぞれは、当該元素の含有量（重量％）を意味する）
Moreover, the following relational expression 2 can be satisfied.
[Relational expression 2] 1.0<[Ti]/3.42[N]<2.0
(In relational expression 2, [Ti] and [N] each mean the content (wt%) of the element)
また、本発明の一ＴｉＮ介在物のサイズは、１５μｍ以下であってもよい。 Moreover, the size of one TiN inclusion of the present invention may be 15 μm or less.
本発明の遅れ破壊抵抗性が向上した線材の製造方法は、重量％で、Ｃ：０．１５～０．３０％、Ｓｉ：０．１５～０．２５％、Ｍｎ：０．９５～１．３５％、Ｐ：０．０３０％以下、Ｓ：０．０３０％以下、Ｔｉ：０．０１５～０．０３０％、Ｂ：０．００１０～０．００４０％、Ｎ：０．００１０～０．００８０％を含み、残部がＦｅおよび不可避な不純物からなり、下記関係式１を満たす鋼材を８８０～９８０℃で仕上げ圧延する段階と、
８３０～９３０℃で巻き取る段階とを含むことを特徴とする。
［関係式１］２．０≦５．５×［Ｓｉ］＋［Ｍｎ］≦２．４
（関係式１中、［Ｓｉ］および［Ｍｎ］それぞれは、当該元素の含有量（重量％）を意味する）
The method for manufacturing a wire rod with improved delayed fracture resistance according to the present invention is as follows: C: 0.15-0.30%, Si: 0.15-0.25%, Mn: 0.95-1. 35%, P: 0.030% or less, S: 0.030% or less, Ti: 0.015 to 0.030%, B: 0.0010 to 0.0040%, N: 0.0010 to 0.0080 %, the remainder consists of Fe and unavoidable impurities, and the step of finish rolling a steel material that satisfies the following
The method is characterized in that it includes a step of winding at 830 to 930°C.
[Relational expression 1] 2.0≦5.5×[Si]+[Mn]≦2.4
(In
また、本発明の、鋼材は、下記関係式２を満たすことができる。
［関係式２］１．０＜［Ｔｉ］／３．４２［Ｎ］＜２．０
（関係式２中、［Ｔｉ］および［Ｎ］それぞれは、当該元素の含有量（重量％）を意味する）
Moreover, the steel material of the present invention can satisfy the following relational expression 2.
[Relational expression 2] 1.0<[Ti]/3.42[N]<2.0
(In relational expression 2, [Ti] and [N] each mean the content (wt%) of the element)
本発明の遅れ破壊抵抗性が向上した部品の製造方法は、本発明によって製造した線材を伸線する段階と、伸線した線材を７４５～７７０℃で球状化熱処理する段階と、球状化熱処理した線材を８７０～９４０℃の温度範囲で加熱する段階と、球状化熱処理した線材を５０～８０℃の温度範囲で焼入する段階と、焼入した部品を４００～６００℃の温度範囲で焼き戻しする段階とを含むことを特徴とする。 The method of manufacturing a component with improved delayed fracture resistance of the present invention includes the steps of drawing the wire produced according to the present invention, subjecting the drawn wire to spheroidizing heat treatment at 745 to 770°C, and spheroidizing the wire rod. A step of heating the wire rod in a temperature range of 870 to 940 degrees Celsius, a step of quenching the spheroidized wire rod in a temperature range of 50 to 80 degrees Celsius, and a step of tempering the quenched parts in a temperature range of 400 to 600 degrees Celsius. The method is characterized by including the step of:
本発明の遅れ破壊抵抗性が向上した部品は、重量％で、Ｃ：０．１５～０．３０％、Ｓｉ：０．１５～０．２５％、Ｍｎ：０．９５～１．３５％、Ｐ：０．０３０％以下、Ｓ：０．０３０％以下、Ｔｉ：０．０１５～０．０３０％、Ｂ：０．００１０～０．００４０％、Ｎ：０．００１０～０．００８０％を含み、残部がＦｅおよび不可避な不純物からなり、下記関係式１を満たすことを特徴とする。
［関係式１］２．０≦５．５×［Ｓｉ］＋［Ｍｎ］≦２．４
（関係式１中、［Ｓｉ］および［Ｍｎ］それぞれは、当該元素の含有量（重量％）を意味する）
The parts with improved delayed fracture resistance of the present invention include, in weight percent, C: 0.15 to 0.30%, Si: 0.15 to 0.25%, Mn: 0.95 to 1.35%, Contains P: 0.030% or less, S: 0.030% or less, Ti: 0.015 to 0.030%, B: 0.0010 to 0.0040%, N: 0.0010 to 0.0080%. , the remainder consists of Fe and unavoidable impurities, and the following
[Relational expression 1] 2.0≦5.5×[Si]+[Mn]≦2.4
(In
また、本発明の部品は、下記関係式２を満たす。
［関係式２］１．０＜［Ｔｉ］／３．４２［Ｎ］＜２．０
（関係式２中、［Ｔｉ］および［Ｎ］それぞれは、当該元素の含有量（重量％）を意味する）
Further, the component of the present invention satisfies the following relational expression 2.
[Relational expression 2] 1.0<[Ti]/3.42[N]<2.0
(In relational expression 2, [Ti] and [N] each mean the content (wt%) of the element)
また、本発明の部品は、体積分率で、残留オーステナイトを０．３～２％および残余の焼き戻しマルテンサイト組織を含む。 The parts of the invention also contain, by volume fraction, 0.3 to 2% retained austenite and a residual tempered martensitic structure.
本発明によれば、遅れ破壊抵抗性が向上した高強度ボルト用部品は、Ｍｎ－Ｂ鋼のボルトねじ部の加工時の成形性を向上させることによって、ボルトねじ部のクラックを発生させないので、１Ｇｐａ級高強度ボルトで遅れ破壊を抑制することができる。 According to the present invention, the high-strength bolt parts with improved delayed fracture resistance do not cause cracks in the bolt thread part by improving the formability during machining of the Mn-B steel bolt thread part. Delayed fracture can be suppressed with 1 Gpa class high strength bolts.
本明細書が実施例のすべての要素を説明するものではなく、本発明の属する技術分野において一般的な内容または実施例の間に重複する内容は省略する。 This specification does not describe all elements of the embodiments, and content that is common in the technical field to which the present invention pertains or content that overlaps between the embodiments is omitted.
また、任意の部分が或る構成要素を「含む」というとき、これは、特に反対になる記載がない限り、他の構成要素を除くものではなく、他の構成要素をさらに含むことができることを意味する。 Furthermore, when we say that any part "contains" a certain component, this does not mean that it excludes other components, unless there is a statement to the contrary, but it does not mean that it excludes other components, and that it can further include other components. means.
単数の表現は、文脈上、明白に例外がない限り、複数の表現を含む。 References to the singular include the plural unless the context clearly dictates otherwise.
以下、本発明を詳細に説明する。
以下の実施形態は、本発明の属する技術分野における通常の知識を有する者に本発明の思想を十分に伝達するために提示するものである。本発明は、ここで提示した実施例のみに限定されず、他の形態で具体化することもできる。
The present invention will be explained in detail below.
The following embodiments are provided so that the spirit of the invention will be fully conveyed to those skilled in the art to which the invention pertains. The invention is not limited only to the embodiments presented here, but can also be embodied in other forms.
本発明の発明者らは、ＳｉおよびＭｎの含有量を制御する場合、固溶強化効果を最適化して強度を確保しながらも、成形性を向上させることができ、ねじ部の成形劣化によるクラック発生を抑制し、遅れ破壊抵抗性を向上させることができることを知見した。 The inventors of the present invention have found that when controlling the content of Si and Mn, it is possible to optimize the solid solution strengthening effect and ensure strength while improving formability and preventing cracks due to deterioration in forming of threaded parts. We found that it is possible to suppress the occurrence of cracking and improve delayed fracture resistance.
また、ＴｉおよびＮの含有量を制御し、ＴｉＮ介在物のサイズを制御することによって、結晶粒を微細化することができ、これによって、成形性が向上し、遅れ破壊抵抗性を確保することができることを知見し、本発明を完成するに至った。 In addition, by controlling the content of Ti and N and the size of TiN inclusions, it is possible to refine the crystal grains, thereby improving formability and ensuring delayed fracture resistance. The present invention was completed based on the discovery that this can be done.
本発明の一実施形態による遅れ破壊抵抗性が向上した線材は、重量％で、Ｃ：０．１５～０．３０％、Ｓｉ：０．１５～０．２５％、Ｍｎ：０．９５～１．３５％、Ｐ：０．０３０％以下、Ｓ：０．０３０％以下、Ｔｉ：０．０１５～０．０３０％、Ｂ：０．００１０～０．００４０％、Ｎ：０．００１０～０．００８０％を含み、残部がＦｅおよび不可避な不純物からなる。 The wire rod with improved delayed fracture resistance according to an embodiment of the present invention has C: 0.15 to 0.30%, Si: 0.15 to 0.25%, Mn: 0.95 to 1 in weight percent. .35%, P: 0.030% or less, S: 0.030% or less, Ti: 0.015-0.030%, B: 0.0010-0.0040%, N: 0.0010-0. The remainder consists of Fe and unavoidable impurities.
以下、本発明の実施形態における合金成分元素含有量の数値限定理由について説明する。以下では、特段の言及がない限り、単位は、重量％である。 Hereinafter, the reason for numerically limiting the content of alloy component elements in the embodiment of the present invention will be explained. In the following, units are % by weight, unless otherwise stated.
炭素（Ｃ）の含有量は、０．１５～０．３０％である。
Ｃは、製品の強度を確保するために添加される元素である。炭素含有量が０．１５％未満の場合、本発明において目標とする強度を確保することが難しく、０．３０％を超過する場合、焼入（Ｑｕｅｎｃｈｉｎｇ）の際に、ラスマルテンサイト（ｌａｔｈ Ｍａｒｔｅｎｓｉｔｅ）境界で静水圧により形成される機械的安定性（ｍｅｃｈａｎｉｃａｌ ｓｔａｂｉｌｉｚａｔｉｏｎ）に優れた残留オーステナイト形成を妨害し、遅れ破壊抵抗性が劣化することができる。したがって、本発明では、Ｃの含有量を０．１５～０．３０％に制限する。
The carbon (C) content is 0.15 to 0.30%.
C is an element added to ensure the strength of the product. When the carbon content is less than 0.15%, it is difficult to secure the target strength in the present invention, and when it exceeds 0.30%, lath martensite (lath martensite) is formed during quenching. ) The formation of retained austenite with excellent mechanical stability formed by hydrostatic pressure at the boundary can be hindered, and the delayed fracture resistance can be deteriorated. Therefore, in the present invention, the C content is limited to 0.15 to 0.30%.
シリコン（Ｓｉ）の含有量は、０．１５～０．２５％である。
Ｓｉは、鋼の脱酸のために有用であるだけでなく、固溶強化を通した強度確保にも効果的な元素である。Ｓｉの含有量が０．１５％未満の場合、鋼の脱酸および固溶強化を通した強度確保が不十分であり、０．２５％を超過する場合には、固溶強化による成形性および衝撃特性が劣化することができる。したがって、本発明では、Ｓｉの含有量を０．１５～０．２５％に制限する。
The content of silicon (Si) is 0.15 to 0.25%.
Si is an element that is not only useful for deoxidizing steel, but also effective for ensuring strength through solid solution strengthening. If the Si content is less than 0.15%, the strength obtained through deoxidation and solid solution strengthening of the steel will be insufficient, and if it exceeds 0.25%, the formability and formability due to solid solution strengthening will be insufficient. Impact properties may deteriorate. Therefore, in the present invention, the Si content is limited to 0.15 to 0.25%.
マンガン（Ｍｎ）の含有量は、０．９５～１．３５％である。
Ｍｎは、硬化能を向上させる元素であり、基地組織内に置換型固溶体を形成し、固溶強化効果を奏する非常に有用な元素である。Ｍｎの含有量が０．９５％未満の場合、前述した固溶強化効果と硬化能が不十分で、本発明において目標とする強度確保が難しく、１．３５％を超過する場合には、固溶強化効果によって成形性が劣化することができる。したがって、本発明では、Ｍｎの含有量を０．９５～１．３５％に制限する。
The content of manganese (Mn) is 0.95 to 1.35%.
Mn is an element that improves hardenability, and is a very useful element that forms a substitutional solid solution within the matrix structure and has a solid solution strengthening effect. If the Mn content is less than 0.95%, the above-mentioned solid solution strengthening effect and hardening ability will be insufficient, making it difficult to secure the target strength in the present invention, and if it exceeds 1.35%, Formability can deteriorate due to the melt strengthening effect. Therefore, in the present invention, the Mn content is limited to 0.95 to 1.35%.
リン（Ｐ）の含有量は、０．０３０％以下である（０％は除外）。
Ｐは、結晶粒界に偏析して靭性を低下させ、遅れ破壊抵抗性を減少させる元素である。したがって、本発明では、Ｐの上限を０．０３０％に制限する。
The content of phosphorus (P) is 0.030% or less (0% is excluded).
P is an element that segregates at grain boundaries and reduces toughness and delayed fracture resistance. Therefore, in the present invention, the upper limit of P is limited to 0.030%.
硫黄（Ｓ）の含有量は、０．０３０％以下である（０％は除外）。
Ｓは、Ｐと同様に、結晶粒界に偏析して靭性を低下させるだけでなく、低融点硫化物を形成させて熱間圧延を阻害する元素である。したがって、本発明では、Ｓの上限を０．０３０％に制限する。
The content of sulfur (S) is 0.030% or less (0% is excluded).
Like P, S is an element that not only segregates at grain boundaries and reduces toughness, but also forms low melting point sulfides and inhibits hot rolling. Therefore, in the present invention, the upper limit of S is limited to 0.030%.
チタン（Ｔｉ）の含有量は、０．０１５～０．０３０％である。
Ｔｉは、鋼中内に流入するＮと結合し、チタン炭窒化物（ＴｉＮ）を形成する元素である。本発明においてＴｉＮは、結晶粒を微細化することによって、部品成形時に成形劣化によるクラック発生を抑制し、遅れ破壊抵抗性を向上させることができる。また、Ｔｉは、ＴｉＮを形成するので、ｆｒｅｅ－Ｎ（自由Ｎ）がＢと結合するのを防止し、成形性を劣化させるＢＮ形成を抑制させることもできる。Ｔｉの含有量が０．０１５％未満の場合、前述したように、十分なＴｉＮが形成されず、自由ＮがＢＮを形成するので、Ｂの硬化能効果を活用しにくく、０．０３％を超過する場合には、粗大な炭窒化物が形成され、遅れ破壊抵抗性が劣化することができる。したがって、本発明では、Ｔｉの含有量を０．０１５～０．０３％に制限する。
The content of titanium (Ti) is 0.015 to 0.030%.
Ti is an element that combines with N flowing into the steel to form titanium carbonitride (TiN). In the present invention, TiN can suppress the occurrence of cracks due to molding deterioration during component molding by making the crystal grains finer, and can improve delayed fracture resistance. Furthermore, since Ti forms TiN, it is possible to prevent free-N from bonding with B, thereby suppressing the formation of BN which deteriorates formability. If the Ti content is less than 0.015%, as described above, sufficient TiN will not be formed and free N will form BN, making it difficult to utilize the hardenability effect of B. If it exceeds, coarse carbonitrides may be formed and delayed fracture resistance may deteriorate. Therefore, in the present invention, the Ti content is limited to 0.015 to 0.03%.
ボロン（Ｂ）の含有量は、０．００１０～０．００４０％である。
Ｂは、硬化能を向上させる元素である。Ｂの含有量が０．００１０％未満の場合、前述した硬化能向上効果を期待しにくく、０．００４０％を超過する場合には、結晶粒界にＦｅ２３（ＣＢ）６炭化物を形成させてオーステナイト結晶粒界の脆性を誘発し、ＢＮを形成して成形性を劣化させることによって、遅れ破壊抵抗性を劣化させる。したがって、本発明では、Ｂ含有量を０．００１０～０．００４０％に制限する。
The content of boron (B) is 0.0010 to 0.0040%.
B is an element that improves hardenability. If the B content is less than 0.0010%, it is difficult to expect the above-mentioned hardenability improvement effect, and if it exceeds 0.0040%, Fe 23 (CB) 6 carbide is formed at the grain boundaries. Delayed fracture resistance is deteriorated by inducing brittleness of austenite grain boundaries, forming BN and deteriorating formability. Therefore, in the present invention, the B content is limited to 0.0010 to 0.0040%.
窒素（Ｎ）の含有量は、０．００１０～０．００８０％である。
Ｎは、炭窒化物を形成する元素である。Ｎの含有量が０．００１０％未満の場合、結晶粒を微細化するＴｉＮ析出物を十分に形成できず、０．００８０％を超過する場合、固溶窒素量が増加し、鋼の靭性および軟性が劣化することができ、ｆｒｅｅ－Ｎ（自由Ｎ）がＢと結合し、成形性を劣化させるＢＮを形成することができる。したがって、本発明では、Ｎの含有量を０．００１０～０．００８０％に制限する。
The nitrogen (N) content is 0.0010 to 0.0080%.
N is an element that forms carbonitrides. If the N content is less than 0.0010%, TiN precipitates that refine grains cannot be sufficiently formed, and if it exceeds 0.0080%, the amount of solid solute nitrogen increases, which deteriorates the toughness of the steel. Softness can deteriorate, and free-N can combine with B to form BN, which deteriorates formability. Therefore, in the present invention, the N content is limited to 0.0010 to 0.0080%.
合金組成以外の残部は、鉄（Ｆｅ）である。本発明の遅れ破壊抵抗性が向上した線材は、通常、鋼の工業的生産過程で含まれ得るその他の不純物を含んでもよい。このような不純物は、本発明の属する技術分野における通常の知識を有する者なら誰でも知ることができる内容であるから、本発明において特にその種類と含有量を制限しない。 The remainder other than the alloy composition is iron (Fe). The wire rod with improved delayed fracture resistance of the present invention may contain other impurities that may normally be included in the industrial production process of steel. Since such impurities are known to anyone with ordinary knowledge in the technical field to which the present invention pertains, the present invention does not particularly limit the type and content thereof.
本発明の一実施形態による遅れ破壊抵抗性が向上した線材は、下記関係式１を満たす。
［関係式１］２．０≦５．５×［Ｓｉ］＋［Ｍｎ］≦２．４
A wire rod with improved delayed fracture resistance according to an embodiment of the present invention satisfies the following
[Relational expression 1] 2.0≦5.5×[Si]+[Mn]≦2.4
関係式１中、［Ｓｉ］および［Ｍｎ］それぞれは、当該元素の含有量（重量％）を意味する。
In
本発明では、ＳｉおよびＭｎの含有量を制御して固溶強化効果を通じて強度を確保しながらも、過度な固溶強化効果を抑制して線材の成形性を向上させ、遅れ破壊抵抗性を向上させようとした。これによって、導き出された関係式１は、固溶強化効果を最適化するための数式である。関係式１の５．５×［Ｓｉ］＋［Ｍｎ］の値が２．０未満の場合、本発明において目標とする強度を確保できず、５．５×［Ｓｉ］＋［Ｍｎ］の値が２．４を超過する場合、過度な固溶強化効果によって、高強度部品の成形の際に成形劣化によるクラックが発生し、遅れ破壊を誘発することができる。したがって、本発明では、遅れ破壊抵抗性を向上させるために、５．５×［Ｓｉ］＋［Ｍｎ］の値を２．０～２．４に制限する。
In the present invention, the content of Si and Mn is controlled to ensure strength through the solid solution strengthening effect, while suppressing excessive solid solution strengthening effect to improve the formability of the wire rod and improve delayed fracture resistance. I tried to make it happen. Accordingly, the derived
また、本発明の一実施形態による遅れ破壊抵抗性が向上した線材は、下記関係式２を満たす。 Further, the wire rod with improved delayed fracture resistance according to an embodiment of the present invention satisfies the following relational expression 2.
［関係式２］１．０＜［Ｔｉ］／３．４２［Ｎ］＜２．０ [Relational expression 2] 1.0<[Ti]/3.42[N]<2.0
関係式２中、［Ｔｉ］および［Ｎ］それぞれは、当該元素の含有量（重量％）を意味する。 In relational formula 2, [Ti] and [N] each mean the content (weight %) of the element.
本発明では、結晶粒を微細化し、成形性を向上させることによって、線材の遅れ破壊抵抗性を向上させようとした。本発明の発明者らは、研究を重ねたところ、ＴｉＮ介在物を形成し、そのサイズを制御して結晶粒を微細化し、ＢＮを抑制することによって、成形性および遅れ破壊抵抗性を確保することができた。これによって、導き出された関係式２は、ＴｉＮ介在物のサイズを制御し、ＢＮの形成を抑制するための数式である。関係式２の［Ｔｉ］／３．４２［Ｎ］値が１．０以下の場合、Ｔｉと結合しないｆｒｅｅ－Ｎにより形成されるＢＮなどによって成形性が劣化することができ、［Ｔｉ］／３．４２［Ｎ］値が２．０以上の場合、超過Ｔｉ（ｅｘｃｅｓｓ Ｔｉ）によってＴｉＮが粗大化し、結晶粒微細化効果を発揮することができない。したがって、本発明では、［Ｔｉ］／３．４２［Ｎ］値を１．０超過～２．０未満に制限する。 In the present invention, an attempt was made to improve the delayed fracture resistance of the wire by making the crystal grains finer and improving the formability. After repeated research, the inventors of the present invention have found that formability and delayed fracture resistance are ensured by forming TiN inclusions, controlling their size to refine crystal grains, and suppressing BN. I was able to do that. Accordingly, the derived relational expression 2 is a mathematical expression for controlling the size of TiN inclusions and suppressing the formation of BN. When the [Ti]/3.42 [N] value in relational expression 2 is 1.0 or less, the formability may be deteriorated by BN formed by free-N that does not combine with Ti, and the [Ti]/ 3.42 When the [N] value is 2.0 or more, TiN becomes coarse due to excess Ti, and the crystal grain refining effect cannot be exhibited. Therefore, in the present invention, the [Ti]/3.42[N] value is limited to more than 1.0 and less than 2.0.
本発明において結晶粒を微細化するためのＴｉＮ介在物のサイズは、１５μｍ以下であってもよい。前述したように、ＴｉＮ介在物の最大サイズが１５μｍを超過する場合、結晶粒微細化による遅れ破壊抵抗性を確保しにくい。 In the present invention, the size of TiN inclusions for refining crystal grains may be 15 μm or less. As described above, when the maximum size of TiN inclusions exceeds 15 μm, it is difficult to ensure delayed fracture resistance due to grain refinement.
また、本発明による線材により製造した遅れ破壊抵抗性が向上した部品は、体積分率で、残留オーステナイトを０．３～２％および残余の焼き戻しマルテンサイト組織を含む。残留オーステナイト組織分率が０．３％未満の場合、遅れ破壊抵抗性を劣化させる水素拡散を遅延させる障害物の役割を期待しにくく、２％を超過する場合、残留オーステナイトがラス境界だけでなく、オーステナイト結晶粒界などに厚く形成され、水素拡散を遅延させにくく、これによって、遅れ破壊抵抗性の改善効果を低減することができる。 In addition, the parts with improved delayed fracture resistance produced by the wire according to the present invention contain a volume fraction of 0.3 to 2% retained austenite and a residual tempered martensitic structure. If the retained austenite structure fraction is less than 0.3%, it is difficult to expect that it will play a role as an obstacle that retards hydrogen diffusion, which deteriorates delayed fracture resistance, and if it exceeds 2%, retained austenite will not only form at lath boundaries , is formed thickly at austenite grain boundaries, etc., and is difficult to delay hydrogen diffusion, thereby reducing the effect of improving delayed fracture resistance.
次に、本発明の一実施形態による遅れ破壊抵抗性が向上した線材および部品の製造方法について説明する。 Next, a method for manufacturing wire rods and components with improved delayed fracture resistance according to an embodiment of the present invention will be described.
本発明による遅れ破壊抵抗性が向上した線材および部品は、多様な方法で製造することができ、その製造方法は特に制限されない。ただし、一実施形態として次のような方法によって製造することができる。 The wire rod and component with improved delayed fracture resistance according to the present invention can be manufactured by various methods, and the manufacturing method is not particularly limited. However, as one embodiment, it can be manufactured by the following method.
本発明による遅れ破壊抵抗性が向上した線材は、重量％で、Ｃ：０．１５～０．３０％、Ｓｉ：０．１５～０．２５％、Ｍｎ：０．９５～１．３５％、Ｐ：０．０３０％以下、Ｓ：０．０３０％以下、Ｔｉ：０．０１５～０．０３０％、Ｂ：０．００１０～０．００４０％、Ｎ：０．００１０～０．００８０％を含み、残部がＦｅおよび不可避な不純物からなる鋼材を８８０～９８０℃で仕上げ圧延する段階と、８３０～９３０℃で巻き取る段階とを含む。 The wire rod with improved delayed fracture resistance according to the present invention has, in weight percent, C: 0.15 to 0.30%, Si: 0.15 to 0.25%, Mn: 0.95 to 1.35%, Contains P: 0.030% or less, S: 0.030% or less, Ti: 0.015 to 0.030%, B: 0.0010 to 0.0040%, N: 0.0010 to 0.0080%. , a step of finish rolling a steel material with the balance consisting of Fe and unavoidable impurities at 880 to 980°C, and a step of winding it at 830 to 930°C.
まず、前述した合金組成を満たす鋼材を用意し、８８０～９８０℃で仕上げ線材圧延する。その後、圧延した線材を８３０～９３０℃でコイル形状に巻き取る。 First, a steel material satisfying the alloy composition described above is prepared and finished wire rod rolled at 880 to 980°C. Thereafter, the rolled wire is wound into a coil shape at 830 to 930°C.
この際、線材圧延温度が８８０℃未満または巻取温度が８３０℃未満の場合、表面層が準二相域であるから、相変態による表面フェライト脱炭層を形成することができ、ボルトの熱処理時にも表面にフェライト脱炭層が形成され、遅れ破壊抵抗性を劣化させることができる。また、ボルト製品の旧オーステナイト結晶粒径が微細になり、残留オーステナイト分率が高まって、遅れ破壊抵抗性を劣化さることができる。なお、線材仕上げ圧延温度が９８０℃を超過したり、巻取温度が９３０℃を超過したりする場合、拡散によって脱炭が加速化し、表面にフェライト脱炭層を形成することができ、旧オーステナイト結晶粒径が粗大になり、遅れ破壊抵抗性を劣化することができる。 At this time, if the wire rolling temperature is less than 880°C or the coiling temperature is less than 830°C, the surface layer is in a quasi-two-phase region, so a surface ferrite decarburized layer can be formed due to phase transformation, and even during heat treatment of the bolt. A ferrite decarburized layer is formed on the surface, which can deteriorate delayed fracture resistance. In addition, the prior austenite crystal grain size of the bolt product becomes fine, the retained austenite fraction increases, and the delayed fracture resistance can be deteriorated. In addition, when the wire finish rolling temperature exceeds 980°C or the coiling temperature exceeds 930°C, decarburization is accelerated due to diffusion, and a ferrite decarburized layer can be formed on the surface, and prior austenite crystals The grain size becomes coarse and delayed fracture resistance can deteriorate.
次に、巻き取られた線材は、目的に合うように、伸線－球状化熱処理－皮膜処理－ボルト成形－オーステナイト化（ａｕｓｔｅｎｉｔｉｚｉｎｇ）－焼入－焼き戻しを行うことによって、最終ボルト用部品に製造することができる。ただし、一実施形態として次のような方法によって製造することができる。 The wound wire rod is then subjected to wire drawing, spheroidization heat treatment, film treatment, bolt forming, austenitizing, quenching, and tempering to form the final bolt part. can be manufactured. However, as one embodiment, it can be manufactured by the following method.
本発明の一実施形態によるボルト用部品の製造方法は、本発明によって製造した線材を伸線する段階と、伸線した線材を７４５～７７０℃で球状化熱処理する段階と、球状化熱処理した線材を８７０～９４０℃で加熱する段階と、球状化熱処理した線材を５０～８０℃で焼入する段階と、４００～６００℃で焼き戻しする段階とを含む。 A method for manufacturing bolt parts according to an embodiment of the present invention includes the steps of drawing a wire rod manufactured according to the present invention, a step of subjecting the drawn wire rod to a spheroidizing heat treatment at 745 to 770°C, and a step of spheroidizing the wire rod subjected to the spheroidizing heat treatment. The steps include heating the wire at 870 to 940°C, quenching the spheroidized wire at 50 to 80°C, and tempering it at 400 to 600°C.
この際、球状化熱処理は、７４５～７７０℃で行われ得る。熱処理温度が７４５℃未満であるか、７７０℃を超過する場合、球状化率が低くなるにつれて、球状化熱処理材の硬度が高まり、ボルト成形後、ねじ部の加工時に成形性が劣化し、そのため、ねじ部クラックを誘発することができる。 At this time, the spheroidization heat treatment may be performed at 745 to 770°C. When the heat treatment temperature is less than 745℃ or exceeds 770℃, the hardness of the spheroidization heat-treated material increases as the spheroidization rate decreases, and the formability deteriorates when processing the threaded part after bolt formation. , can induce thread cracks.
オーステナイト化熱処理は、８７０～９４０℃で行われ得る。熱処理温度が８７０℃未満の場合、オーステナイト逆変態が十分に起こらないので、焼入後、マルテンサイト組織が不均一に形成され、靭性が劣化することができる。なお、熱処理温度が９４０℃を超過する場合には、旧オーステナイト結晶粒度が粗大になり、遅れ破壊抵抗性が劣化することができる。 The austenitizing heat treatment may be performed at 870-940°C. When the heat treatment temperature is less than 870° C., austenite reverse transformation does not occur sufficiently, so that after quenching, a martensitic structure is formed non-uniformly, and the toughness may deteriorate. Note that if the heat treatment temperature exceeds 940° C., the prior austenite crystal grain size becomes coarse and delayed fracture resistance may deteriorate.
また、焼入は、５０～８０℃の温度範囲で行われ得る。焼入冷媒の温度が５０℃未満の場合、ボルトのねじ山で熱変形による微細な焼入割れ（Ｑｕｅｎｃｈｉｎｇ Ｃｒａｃｋ）が発生することがあり、遅れ破壊を誘発することができ、８０℃を超過する場合、十分な焼入が行われず、ラスに機械的安定残留オーステナイトの他に、旧オーステナイト結晶粒界に残留オーステナイトが形成され、かえって水素の捕捉部として作用し、遅れ破壊を誘発することができる。 Also, quenching can be performed at a temperature range of 50-80°C. If the temperature of the quenching refrigerant is less than 50℃, fine quenching cracks may occur due to thermal deformation on the bolt threads, which can induce delayed fracture, and if the temperature exceeds 80℃. In this case, sufficient quenching is not performed, and in addition to the mechanically stable retained austenite in the lath, retained austenite is formed at the grain boundaries of prior austenite, which acts as a hydrogen trap and can induce delayed fracture. .
また、焼き戻しは、４００～６００℃の温度範囲で行われ得、最終製品の用途および目的に合うように、強度および靭性を付与することができる。焼き戻し温度が４００℃未満の場合、焼き戻しによる脆性を誘発することができ、６００℃を超過する場合、本発明において意図する強度を具現し難い。 Tempering can also be carried out at temperatures ranging from 400 to 600° C. to impart strength and toughness to suit the application and purpose of the final product. If the tempering temperature is less than 400°C, brittleness may occur due to tempering, and if it exceeds 600°C, it is difficult to achieve the strength intended in the present invention.
本発明によって製造した遅れ破壊抵抗性が向上した部品は、体積分率で、残留オーステナイトを０．３～２％および残余の焼き戻しマルテンサイト組織を含む。 Parts with improved delayed fracture resistance produced according to the present invention contain, by volume fraction, 0.3 to 2% retained austenite and a residual tempered martensitic structure.
以下、実施例に基づいて本発明をより具体的に説明する。ただし、下記の実施例は、本発明を例示してより詳細に説明するためのものであり、本発明の権利範囲を限定するためのものではないという点に留意すべきである。本発明の権利範囲は、特許請求範囲に記載された事項とこれから合理的に類推される事項によって決定されるものであるからである。 Hereinafter, the present invention will be explained more specifically based on Examples. However, it should be noted that the following examples are intended to illustrate and explain the present invention in more detail, and are not intended to limit the scope of the present invention. This is because the scope of rights in the present invention is determined by the matters stated in the claims and matters reasonably inferred from these matters.
実施例
下記表１の合金組成を満たす発明例１～６、比較例１～５の線材を本発明による製造条件で製造し、最終試験用ボルトを得た。具体的には、下記表１の合金組成を満たす鋼片を８８０～９８０℃で仕上げ線材圧延し、８３０～９３０℃でコイル形状に巻き取った後、巻き取られた線材を最大温度７４５～７７０℃で球状化熱処理した。次に、球状化熱処理した線材をボルトに成形し、８７０～９４０℃でオーステナイト化した後、５０～８０℃の冷媒に焼入し、その後、１０５０±１６ＭＰａの引張強度を確保するために、４００～６００℃の温度で焼き戻しを行い、最終ボルト製品を得た。
Examples Wire rods of Invention Examples 1 to 6 and Comparative Examples 1 to 5 satisfying the alloy compositions shown in Table 1 below were manufactured under the manufacturing conditions of the present invention to obtain bolts for final testing. Specifically, a steel billet satisfying the alloy composition shown in Table 1 below is finished wire-rolled at 880 to 980°C, wound into a coil shape at 830 to 930°C, and then the wound wire is heated to a maximum temperature of 745 to 770°C. Spheroidization heat treatment was carried out at ℃. Next, the spheroidized wire rod is formed into a bolt, austenitized at 870-940℃, quenched in a refrigerant at 50-80℃, and then heated to 400℃ to ensure a tensile strength of 1050±16MPa. Tempering was carried out at a temperature of ~600°C to obtain the final bolt product.
次に、発明例１～６、比較例１～５のボルト製品について、ＴｉＮ析出物の最大サイズ、遅れ破壊クラックの有無を評価し、関係式１および関係式２の値と共に表２に示した。ＴｉＮ析出物の最大サイズは、ボルト製品をＬ断面（Ｌｏｎｇｉｔｕｄｉｎａｌ ｄｉｒｅｃｔｉｏｎ）に切開し、１６０ｍｍ２面積を３０ｆｉｅｌｄ観察し、極値解析（ｅｘｔｒｅｍｅ ｖａｌｕｅ ａｎａｌｙｓｉｓ）を通じて測定される介在物のサイズを最大介在物のサイズと定義し、その値を下記表２に示した。
Next, the bolt products of Invention Examples 1 to 6 and Comparative Examples 1 to 5 were evaluated for the maximum size of TiN precipitates and the presence or absence of delayed fracture cracks, and the results are shown in Table 2 along with the values of
遅れ破壊抵抗性は、ボルト製品を降伏強度の締結力で構造物に締結した後、５％塩酸＋９５％蒸留水溶液に１０分間浸漬し、応力集中部であるねじ山にクラック有無を観察する遅れ破壊シミュレーションで進めた。クラックが発生しない場合は、Ｘ、クラックが発生した場合は、○で示した。 Delayed fracture resistance is measured by fastening a bolt product to a structure with a fastening force of yield strength, then immersing it in a solution of 5% hydrochloric acid + 95% distilled water for 10 minutes, and observing the presence or absence of cracks in the threads, which are stress concentration areas. Proceeded through simulation. If no cracks occurred, it was marked with an X, and if cracks did occur, it was marked with an O.
表２から確認できるように、本発明において提案する合金組成、関係式およびＴｉＮサイズを満たす発明例１～６は、遅れ破壊抵抗性の評価前後にボルト製品のねじ部で遅れ破壊クラックが発生しなかった。一方、比較例１は、［Ｔｉ］／３．４２［Ｎ］値が２．５０６であり、本発明において提案する上限値である２．０を超過し、粗大なＴｉＮが形成され、そのため、遅れ破壊クラックが発生した。 As can be confirmed from Table 2, in Invention Examples 1 to 6 that satisfy the alloy composition, relational expression, and TiN size proposed in the present invention, delayed fracture cracks occurred in the threaded part of the bolt product before and after evaluating delayed fracture resistance. There wasn't. On the other hand, in Comparative Example 1, the [Ti]/3.42[N] value was 2.506, which exceeded the upper limit of 2.0 proposed in the present invention, and coarse TiN was formed. Delayed fracture cracks occurred.
比較例２は、［Ｔｉ］／３．４２［Ｎ］値が３．０７０であり、本発明において提案する上限値である２．０を超過し、粗大なＴｉＮが形成され、そのため、遅れ破壊クラックが発生した。 In Comparative Example 2, the [Ti]/3.42[N] value was 3.070, which exceeded the upper limit of 2.0 proposed in the present invention, and coarse TiN was formed, resulting in delayed fracture. A crack occurred.
比較例３は、Ｓｉの含有量が０．２６％であり、本発明において提案する上限値である０．２５％を超過し、５．５×［Ｓｉ］＋［Ｍｎ］値が２．５８であり、本発明において提案する上限値である２．４を超過し、過度な固溶強化効果によって球状化熱処理後にボルトねじ部の成形性が劣化し、遅れ破壊クラックが発生した。図１は、遅れ破壊抵抗性の評価前の比較例３のねじ部を観察した写真である。図１を参照すると、比較例３は、本発明において提案する条件を満たしていないので、遅れ破壊クラックが発生し、遅れ破壊抵抗性を確保しなかったことを確認することができる。 In Comparative Example 3, the Si content was 0.26%, which exceeded the upper limit of 0.25% proposed in the present invention, and the 5.5×[Si]+[Mn] value was 2.58. This exceeded the upper limit of 2.4 proposed in the present invention, and due to the excessive solid solution strengthening effect, the formability of the bolt thread portion deteriorated after the spheroidization heat treatment, and delayed fracture cracks occurred. FIG. 1 is a photograph of the threaded portion of Comparative Example 3 before evaluation of delayed fracture resistance. Referring to FIG. 1, it can be confirmed that Comparative Example 3 did not meet the conditions proposed in the present invention, so delayed fracture cracks occurred and delayed fracture resistance was not ensured.
比較例４は、Ｍｎの含有量が１．４５％であり、本発明において提案する上限値である１．３５％を超過し、５．５×［Ｓｉ］＋［Ｍｎ］値が２．６１であり、本発明において提案する上限値である２．４を超過し、過度な固溶強化効果によって球状化熱処理後にボルトねじ部の成形性が劣化し、遅れ破壊クラックが発生した。 In Comparative Example 4, the Mn content was 1.45%, which exceeded the upper limit of 1.35% proposed in the present invention, and the 5.5×[Si]+[Mn] value was 2.61. This exceeded the upper limit of 2.4 proposed in the present invention, and due to the excessive solid solution strengthening effect, the formability of the bolt thread portion deteriorated after the spheroidization heat treatment, and delayed fracture cracks occurred.
比較例５は、Ｃの含有量が０．３３％であり、本発明において提案する上限値である０．３０％を超過し、機械的安定性に優れた残留オーステナイト組織の形成が抑制され、遅れ破壊クラックが発生した。 Comparative Example 5 has a C content of 0.33%, which exceeds the upper limit of 0.30% proposed in the present invention, and the formation of a retained austenite structure with excellent mechanical stability is suppressed. Delayed fracture cracks occurred.
次に、本発明による前記表１の発明例３の合金組成を満たす発明例３、比較例６－１～６－６を下記表３のような製造条件で製造し、最終ボルト製品を得た。 Next, Invention Example 3 and Comparative Examples 6-1 to 6-6 satisfying the alloy composition of Invention Example 3 in Table 1 according to the present invention were manufactured under the manufacturing conditions shown in Table 3 below to obtain final bolt products. .
本発明による仕上げ圧延温度、巻取温度、球状化熱処理温度およびオーステナイト化温度を満たす発明例３は、遅れ破壊クラックが発生しなかった。一方、比較例６－１は、圧延温度が９９０℃であり、本発明において提案する上限である９８０℃を超過し、巻取温度も９４０℃であり、本発明において提案する上限である９３０℃を超過し、線材において旧オーステナイト結晶粒径が粗大になり、ボルト製品の旧オーステナイト結晶粒径も粗大になるにつれて、遅れ破壊クラックが発生した。 In Invention Example 3, which satisfied the finish rolling temperature, coiling temperature, spheroidizing heat treatment temperature, and austenitizing temperature according to the present invention, delayed fracture cracks did not occur. On the other hand, in Comparative Example 6-1, the rolling temperature is 990°C, which exceeds the upper limit of 980°C proposed in the present invention, and the coiling temperature is 940°C, which is 930°C, which is the upper limit proposed in the present invention. was exceeded, the prior austenite crystal grain size in the wire became coarse, and as the prior austenite crystal grain size of the bolt product also became coarse, delayed fracture cracks occurred.
比較例６－２は、圧延温度が８７０℃であり、本発明において提案する下限である８８０℃に達せず、巻取温度も８２０℃であり、本発明において提案する下限である８３０℃に達せず、線材において旧オーステナイト結晶粒径が微細になり、ボルト製品の旧オーステナイト結晶粒径も微細になるにつれて、残留オーステナイト分率が高まり、遅れ破壊クラックが発生した。 In Comparative Example 6-2, the rolling temperature was 870°C, which did not reach the lower limit of 880°C proposed in the present invention, and the coiling temperature was 820°C, which did not reach the lower limit of 830°C proposed in the present invention. First, as the prior austenite crystal grain size in the wire became finer and the prior austenite crystal grain size in the bolt product also became finer, the retained austenite fraction increased and delayed fracture cracks occurred.
比較例６－３は、オーステナイト化熱処理温度が９５０℃であり、本発明において提案する上限である９４０℃を超過し、ボルト製品の旧オーステナイト結晶粒径が粗大になるにつれて、遅れ破壊クラックが発生した。 In Comparative Example 6-3, the austenitizing heat treatment temperature was 950°C, which exceeded the upper limit of 940°C proposed in the present invention, and delayed fracture cracks occurred as the prior austenite crystal grain size of the bolt product became coarser. did.
比較例６－４は、オーステナイト化熱処理温度が８６０℃であり、本発明において提案する下限である８７０℃に達せず、ボルト製品が十分にオーステナイト化しない状態でＱＴ熱処理が行われ、未固溶のパーライトが形成され、これによって、遅れ破壊クラックが発生した。 In Comparative Example 6-4, the austenitizing heat treatment temperature was 860°C, which did not reach the lower limit of 870°C proposed in the present invention, and the QT heat treatment was performed in a state where the bolt product was not sufficiently austenitized. pearlite was formed, which caused delayed fracture cracks.
比較例６－５は、球状化温度が７４０℃であり、本発明において提案する下限である７４５℃に達せず、比較例６－６は、球状化温度が７７５℃であり、本発明において提案する上限である７７０℃を超過し、球状化率が低く、熱処理が十分に行われず、成形性が劣化し、遅れ破壊クラックが発生した。 Comparative Example 6-5 has a spheroidization temperature of 740°C, which does not reach the lower limit of 745°C proposed in the present invention, and Comparative Example 6-6 has a spheroidization temperature of 775°C, which does not reach the lower limit of 745°C proposed in the present invention. The upper limit of 770° C. was exceeded, the spheroidization rate was low, heat treatment was not performed sufficiently, formability deteriorated, and delayed fracture cracks occurred.
以上、本発明の例示的な実施例を説明したが、本発明は、これに限定されず、当該技術分野における通常の知識を有する者なら、本明細書に記載する請求範囲の概念と範囲を逸脱しない範囲内で多様な変更および変形が可能であることを理解することができる。
Although the exemplary embodiments of the present invention have been described above, the present invention is not limited thereto, and a person having ordinary knowledge in the technical field will understand the concept and scope of the claims described in this specification. It can be understood that various changes and modifications can be made without departing from the scope.
Claims (9)
下記関係式１を満たすことを特徴とする、遅れ破壊抵抗性が向上した線材。
［関係式１］２．０≦５．５×［Ｓｉ］＋［Ｍｎ］≦２．４
（関係式１中、［Ｓｉ］および［Ｍｎ］それぞれは、当該元素の含有量（重量％）を意味する） In weight%, C: 0.15 to 0.30%, Si: 0.15 to 0.25%, Mn: 0.95 to 1.35%, P: 0.030% or less, S: 0.030 % or less, Ti: 0.015 to 0.030%, B: 0.0010 to 0.0040%, N: 0.0010 to 0.0080%, the remainder consisting of Fe and inevitable impurities,
A wire rod with improved delayed fracture resistance, characterized by satisfying the following relational expression 1.
[Relational expression 1] 2.0≦5.5×[Si]+[Mn]≦2.4
(In relational formula 1, [Si] and [Mn] each mean the content (wt%) of the element)
［関係式２］１．０＜［Ｔｉ］／３．４２［Ｎ］＜２．０
（関係式２中、［Ｔｉ］および［Ｎ］それぞれは、当該元素の含有量（重量％）を意味する） The wire rod with improved delayed fracture resistance according to claim 1, which satisfies the following relational expression 2.
[Relational expression 2] 1.0<[Ti]/3.42[N]<2.0
(In relational expression 2, [Ti] and [N] each mean the content (wt%) of the element)
８３０～９３０℃で巻き取る段階と、を含むことを特徴とする遅れ破壊抵抗性が向上した、線材の製造方法。
［関係式１］２．０≦５．５×［Ｓｉ］＋［Ｍｎ］≦２．４
（関係式１中、［Ｓｉ］および［Ｍｎ］それぞれは、当該元素の含有量（重量％）を意味する） In weight%, C: 0.15 to 0.30%, Si: 0.15 to 0.25%, Mn: 0.95 to 1.35%, P: 0.030% or less, S: 0.030 % or less, including Ti: 0.015 to 0.030%, B: 0.0010 to 0.0040%, N: 0.0010 to 0.0080%, the remainder consisting of Fe and unavoidable impurities, and the following relationship Finish rolling a steel material satisfying formula 1 at 880 to 980°C;
A method for producing a wire with improved delayed fracture resistance, the method comprising the step of winding at 830 to 930°C.
[Relational expression 1] 2.0≦5.5×[Si]+[Mn]≦2.4
(In relational formula 1, [Si] and [Mn] each mean the content (wt%) of the element)
［関係式２］１．０＜［Ｔｉ］／３．４２［Ｎ］＜２．０
（関係式２中、［Ｔｉ］および［Ｎ］それぞれは、当該元素の含有量（重量％）を意味する） 5. The method for manufacturing a wire rod according to claim 4, wherein the steel material satisfies the following relational expression 2.
[Relational expression 2] 1.0<[Ti]/3.42[N]<2.0
(In relational expression 2, [Ti] and [N] each mean the content (wt%) of the element)
前記伸線した線材を７４５～７７０℃で球状化熱処理する段階と、
前記球状化熱処理した線材を８７０～９４０℃の温度範囲で加熱する段階と、
前記球状化熱処理した線材を５０～８０℃の温度範囲で焼入する段階と、
前記焼入した部品を４００～６００℃の温度範囲で焼き戻しする段階と、を含むことを特徴とする遅れ破壊抵抗性が向上した部品の製造方法。 drawing the wire produced according to claim 4 or claim 5;
heat-treating the drawn wire rod at 745 to 770°C to spheroidize it;
heating the wire rod subjected to the spheroidization heat treatment in a temperature range of 870 to 940°C;
Quenching the spheroidized wire at a temperature range of 50 to 80°C;
A method for manufacturing a component with improved delayed fracture resistance, comprising the step of tempering the quenched component at a temperature range of 400 to 600°C.
［関係式１］２．０≦５．５×［Ｓｉ］＋［Ｍｎ］≦２．４
（関係式１中、［Ｓｉ］および［Ｍｎ］それぞれは、当該元素の含有量（重量％）を意味する） In weight%, C: 0.15 to 0.30%, Si: 0.15 to 0.25%, Mn: 0.95 to 1.35%, P: 0.030% or less, S: 0.030 % or less, including Ti: 0.015 to 0.030%, B: 0.0010 to 0.0040%, N: 0.0010 to 0.0080%, the remainder consisting of Fe and unavoidable impurities, and the following relationship A component with improved delayed fracture resistance, characterized by satisfying Formula 1.
[Relational expression 1] 2.0≦5.5×[Si]+[Mn]≦2.4
(In relational formula 1, [Si] and [Mn] each mean the content (wt%) of the element)
［関係式２］１．０＜［Ｔｉ］／３．４２［Ｎ］＜２．０
（関係式２中、［Ｔｉ］および［Ｎ］それぞれは、当該元素の含有量（重量％）を意味する） The component according to claim 7, characterized in that the following relational expression 2 is satisfied.
[Relational expression 2] 1.0<[Ti]/3.42[N]<2.0
(In relational expression 2, [Ti] and [N] each mean the content (wt%) of the element)
8. Part according to claim 7, characterized in that it comprises, by volume fraction, 0.3 to 2% retained austenite and a residual tempered martensitic structure.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020200178274A KR102492644B1 (en) | 2020-12-18 | 2020-12-18 | Wire rod and parts with improved delayed fracture resisitance and method for manufacturing the same |
| KR10-2020-0178274 | 2020-12-18 | ||
| PCT/KR2021/018977 WO2022131752A1 (en) | 2020-12-18 | 2021-12-14 | Wire rod and parts with improved delayed fracture resistance, and methods for manufacturing same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2024500152A true JP2024500152A (en) | 2024-01-04 |
Family
ID=82059247
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2023537438A Pending JP2024500152A (en) | 2020-12-18 | 2021-12-14 | Wire rods and parts with improved delayed fracture resistance and their manufacturing method |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US20240060162A1 (en) |
| EP (1) | EP4265766A1 (en) |
| JP (1) | JP2024500152A (en) |
| KR (1) | KR102492644B1 (en) |
| CN (1) | CN116783316A (en) |
| WO (1) | WO2022131752A1 (en) |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3966493B2 (en) | 1999-05-26 | 2007-08-29 | 新日本製鐵株式会社 | Cold forging wire and method for producing the same |
| KR101033752B1 (en) * | 2005-02-16 | 2011-05-09 | 신닛뽄세이테쯔 카부시키카이샤 | Hot rolled wire material excellent in cold forging property after spheroidizing treatment, spheroidizing-annealed steel wire having excellent cold forging property, and method for production thereof |
| KR101091446B1 (en) * | 2008-12-26 | 2011-12-07 | 주식회사 포스코 | High Strength Steel Plate with Excellent Resistance of Cyclic Pressure for Low-Temperature Pressure Vessel, Manufacturing Method Thereof and Manufacturing Method of Deep Drawing Article |
| CN102741441B (en) * | 2010-03-02 | 2013-09-11 | 新日铁住金株式会社 | Steel wire with excellent cold forging characteristics and manufacturing process thereof |
| JP6034632B2 (en) * | 2012-03-26 | 2016-11-30 | 株式会社神戸製鋼所 | Boron-added steel for high strength bolts and high strength bolts with excellent delayed fracture resistance |
| JP5776623B2 (en) * | 2012-05-08 | 2015-09-09 | 新日鐵住金株式会社 | Steel wire rods / bars with excellent cold workability and manufacturing method thereof |
| KR101665886B1 (en) | 2015-09-04 | 2016-10-13 | 주식회사 포스코 | Non-quenched and tempered steel having excellent cold workability and impact toughness and method for manufacturing same |
| CN107815594A (en) * | 2017-11-12 | 2018-03-20 | 湖南华菱湘潭钢铁有限公司 | A kind of production method of cold extrusion gear wire rod |
-
2020
- 2020-12-18 KR KR1020200178274A patent/KR102492644B1/en active IP Right Grant
-
2021
- 2021-12-14 CN CN202180090890.8A patent/CN116783316A/en active Pending
- 2021-12-14 US US18/268,061 patent/US20240060162A1/en active Pending
- 2021-12-14 EP EP21907056.2A patent/EP4265766A1/en active Pending
- 2021-12-14 JP JP2023537438A patent/JP2024500152A/en active Pending
- 2021-12-14 WO PCT/KR2021/018977 patent/WO2022131752A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| KR102492644B1 (en) | 2023-01-30 |
| KR20220087847A (en) | 2022-06-27 |
| EP4265766A1 (en) | 2023-10-25 |
| WO2022131752A1 (en) | 2022-06-23 |
| US20240060162A1 (en) | 2024-02-22 |
| CN116783316A (en) | 2023-09-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10577671B2 (en) | High-hardness hot-rolled steel product, and a method of manufacturing the same | |
| CA2962472C (en) | High-toughness hot-rolled high-strength steel with yield strength of grade 800 mpa and preparation method thereof | |
| US20120037283A1 (en) | High-Strength, High-Toughness Steel Wire Rod, and Method for Manufacturing Same | |
| JPH0441616A (en) | Production of low-hardness water-resistant steel excellent in wear resistance and bendability | |
| JPH11236644A (en) | Steel for induction hardening excellent in high strength characteristic and low heat treating strain characteristic and its production | |
| JP2024060017A (en) | Ultra-high strength spring wire rod, steel wire and manufacturing method thereof | |
| CN113966404B (en) | Non-heat-treated wire rod having excellent drawability and impact toughness and method for manufacturing the same | |
| KR101300158B1 (en) | High carbon steel sheet superior in tensile strength and toughness and method for manufacturing the same | |
| JPH1180903A (en) | High strength steel member excellent in delayed fracture characteristic, and its production | |
| JPH039168B2 (en) | ||
| JP3422864B2 (en) | Stainless steel with excellent workability and method for producing the same | |
| JP3422865B2 (en) | Method for producing high-strength martensitic stainless steel member | |
| JP2007513259A (en) | Steel wire for cold heading having excellent low temperature impact characteristics and method for producing the same | |
| JP6390685B2 (en) | Non-tempered steel and method for producing the same | |
| JP2024500152A (en) | Wire rods and parts with improved delayed fracture resistance and their manufacturing method | |
| JPH0526850B2 (en) | ||
| KR20210077505A (en) | Wire rod for high strength cold head quality steel with excellent resistance to hydrogen embrittlement, and method for manufacturing thereof | |
| JP3327065B2 (en) | Method for producing tempered high-strength steel sheet excellent in brittle crack propagation arrestability | |
| JP7427764B2 (en) | High-strength spring wire rod and steel wire and manufacturing method thereof | |
| KR102492631B1 (en) | Wire rod and parts for fastening with improved delayed fracture resisitance and method for manufacturing the same | |
| JPS6156268A (en) | High toughness and high tensile steel and its manufacture | |
| KR101696097B1 (en) | Non heat treated wire rod having excellent high strength and impact toughness and method for manafacturing the same | |
| JP2023542952A (en) | Steel for automobile leaf springs and method for manufacturing the spring plates | |
| KR20240018573A (en) | Hot forming steel parts and manufacturing methods | |
| KR20230049370A (en) | Non-quenched and tempered steel having excellent impact toughness, method for manufacturing the same, and steel part therof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20230810 |