KR20220055271A - High strength galva-annealed steel sheet and method of manufacturing the same - Google Patents
High strength galva-annealed steel sheet and method of manufacturing the same Download PDFInfo
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- rolled steel
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 86
- 239000010959 steel Substances 0.000 title claims abstract description 86
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 35
- 229910000859 α-Fe Inorganic materials 0.000 claims abstract description 43
- 239000011572 manganese Substances 0.000 claims abstract description 41
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 34
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 32
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 31
- 229910000734 martensite Inorganic materials 0.000 claims abstract description 30
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000010703 silicon Substances 0.000 claims abstract description 28
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 28
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 23
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 23
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims abstract description 21
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 21
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims abstract description 20
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 20
- 239000011574 phosphorus Substances 0.000 claims abstract description 20
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 17
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 17
- 239000011593 sulfur Substances 0.000 claims abstract description 17
- 239000012535 impurity Substances 0.000 claims abstract description 16
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910001335 Galvanized steel Inorganic materials 0.000 claims description 53
- 239000008397 galvanized steel Substances 0.000 claims description 53
- 238000001816 cooling Methods 0.000 claims description 43
- 239000010960 cold rolled steel Substances 0.000 claims description 37
- 238000000034 method Methods 0.000 claims description 24
- 238000010438 heat treatment Methods 0.000 claims description 21
- 238000005246 galvanizing Methods 0.000 claims description 19
- 238000005275 alloying Methods 0.000 claims description 18
- 238000000137 annealing Methods 0.000 claims description 17
- 239000000463 material Substances 0.000 claims description 14
- 238000005097 cold rolling Methods 0.000 claims description 11
- 238000005096 rolling process Methods 0.000 claims description 9
- 238000003303 reheating Methods 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 5
- 229910045601 alloy Inorganic materials 0.000 claims description 3
- 239000000956 alloy Substances 0.000 claims description 3
- 238000004804 winding Methods 0.000 claims description 3
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 abstract description 3
- 239000011701 zinc Substances 0.000 abstract description 3
- 229910052725 zinc Inorganic materials 0.000 abstract description 3
- 230000000052 comparative effect Effects 0.000 description 23
- 238000007747 plating Methods 0.000 description 11
- 230000007547 defect Effects 0.000 description 10
- 230000000694 effects Effects 0.000 description 10
- 229910001566 austenite Inorganic materials 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 7
- 238000005728 strengthening Methods 0.000 description 7
- 230000009466 transformation Effects 0.000 description 6
- 230000002159 abnormal effect Effects 0.000 description 5
- 229910001562 pearlite Inorganic materials 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 5
- 230000009467 reduction Effects 0.000 description 5
- 229910000677 High-carbon steel Inorganic materials 0.000 description 4
- 229910001563 bainite Inorganic materials 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000005098 hot rolling Methods 0.000 description 4
- 239000010410 layer Substances 0.000 description 4
- 239000010955 niobium Substances 0.000 description 4
- 230000002829 reductive effect Effects 0.000 description 4
- 230000033228 biological regulation Effects 0.000 description 3
- 229910052758 niobium Inorganic materials 0.000 description 3
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 230000000087 stabilizing effect Effects 0.000 description 3
- 238000005452 bending Methods 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 238000010583 slow cooling Methods 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910001035 Soft ferrite Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- -1 and in this section Inorganic materials 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000016507 interphase Effects 0.000 description 1
- 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 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
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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
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- 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
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
- C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
- C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
- C21D8/0426—Hot rolling
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- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
- C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
- C21D8/0436—Cold rolling
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- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
- C21D8/0447—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment
- C21D8/0457—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment with diffusion of elements, e.g. decarburising, nitriding
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- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/06—Zinc or cadmium or alloys based thereon
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- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
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- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
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- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
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- 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
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Abstract
Description
본 발명의 기술적 사상은 강재에 관한 것으로서, 보다 상세하게는 높은 연신율과 홀확장성 및 우수한 표면 특성, 및 플랜지성을 가지는 고강도 합금화 용융아연도금 강판 및 그 제조방법에 관한 것이다.The technical idea of the present invention relates to a steel material, and more particularly, to a high-strength alloyed hot-dip galvanized steel sheet having high elongation, hole expandability, excellent surface properties, and flangeability, and a method for manufacturing the same.
최근 자동차용 강판은 각종 환경 규제 및 에너지 사용 규제에 의해 연비향상이나 내구성 향상을 위하여 강도가 더욱 높은 강판이 요구되고 있다. 특히, 자동차의 충격 안정성 규제가 확산되면서 차체의 내충격성 향상을 위해 멤버(Member), 시트레일(seat rail) 및 필라(pillar) 등의 구조 부재에 고강도강이 사용되고 있다. 그러나 일반적으로 강판의 강도가 증가할수록 연신율이 감소하게 됨으로써, 성형가공성이 저하되는 문제점이 발생하므로, 이를 보완할 수 있는 재료의 개발이 요구되고 있는 실정이다.Recently, steel sheets for automobiles have been required to have higher strength in order to improve fuel efficiency and durability due to various environmental regulations and energy use regulations. In particular, high-strength steel is being used for structural members such as members, seat rails, and pillars in order to improve the impact resistance of the vehicle body as the impact stability regulation of automobiles spreads. However, in general, as the strength of the steel sheet increases, the elongation decreases, which leads to a problem in that the formability is deteriorated. Therefore, the development of a material that can compensate for this is required.
590MPa급 이상의 강도를 확보하기 위하여, 석출강화 및 변태강화를 활용하여 고강도강을 제조한다. 석출강화의 경우 니오븀(Nb), 티타늄(Ti), 또는 바나듐(V)을 첨가하여 탄질화물을 석출하여 미세석출에 의한 결정립 성장억제를 통해 결정립을 미세화 시켜 강도를 확보 한다. 다만, 석출강화의 경우 열연 권취온도에 따른 석출물 사이즈 및 분포가 달라질 수 있어 냉연제품에서 길이방향 재질편차를 발생시킬 수 있는 문제점이 있으므로, 780MPa급 이상의 고강도강을 제조하는데 어려움이 있다.In order to secure a strength of 590 MPa or higher, high strength steel is manufactured using precipitation strengthening and transformation strengthening. In the case of precipitation strengthening, carbonitride is precipitated by adding niobium (Nb), titanium (Ti), or vanadium (V), and the strength is secured by refining crystal grains by inhibiting grain growth by fine precipitation. However, in the case of precipitation strengthening, there is a problem in that the size and distribution of precipitates may vary according to the hot-rolling temperature, which may cause material deviation in the longitudinal direction in cold-rolled products.
변태강화강의 경우 이상조직강, 복합조직강, 변태유기소성상, 마르텐사이트강, 핫스탬핑강 등 여러 가지 기술이 개발되어 왔다. 특히, 이상조직강은 연질의 페라이트 기지에 경질의 마르텐사이트가 분포하는 강으로 강도와 연신율의 밸런스가 우수하여 590~980MPa급 냉연강판의 개발이 이루어졌고, 상기 자동차용 부품으로 많이 사용되고 있다. 다만 일반적인 이상조직강의 경우 페라이트와 마르텐사이트 상간의 경도차가 크고, 부품 성형 시 두 상의 계면에 응력이 집중되어 굽힘 특성이나 플랜징 특성을 요구하는 부품에 적용 시 가공크랙이 발생하기 쉬운 문제점이 있다. 이러한 특성을 개선하고자 페라이트와 마르텐사이트 이상 간의 경도차를 줄이기 위해 중간상인 베이나이트를 포함하는 복합조직강(Complex Phase)강이 개발되어 있으나 연신율이 저하되는 문제점이 있어 이상조직강에 비해 부품에 적용되는 범용성이 불리하다. In the case of transformation-reinforced steel, various technologies have been developed, such as abnormal-structured steel, composite-structured steel, transformation-induced plasticity, martensitic steel, and hot stamping steel. In particular, the ideal structure steel is a steel in which hard martensite is distributed in a soft ferrite matrix, and has excellent balance between strength and elongation, so a 590-980 MPa grade cold-rolled steel sheet has been developed, and it is widely used as parts for automobiles. However, in the case of general abnormal structure steel, there is a problem that the hardness difference between the ferrite and martensite phases is large, and the stress is concentrated at the interface of the two phases during part molding, so that when applied to parts requiring bending or flanging characteristics, there is a problem that processing cracks are easy to occur. In order to improve these characteristics, a complex phase steel containing bainite, an intermediate phase, has been developed to reduce the difference in hardness between ferrite and martensite, but it has a problem in that elongation is lowered, so it is applied to parts compared to ideal steel Its versatility is disadvantageous.
본 발명의 기술적 사상이 이루고자 하는 기술적 과제는, 높은 연신율과 홀확장성 및 우수한 표면 특성, 및 플랜지성을 가지는 고강도 합금화 용융아연도금 강판 및 그 제조방법을 제공하는 것이다.The technical problem to be achieved by the technical idea of the present invention is to provide a high-strength alloyed hot-dip galvanized steel sheet having high elongation, hole expandability, excellent surface properties, and flangeability, and a method for manufacturing the same.
그러나 이러한 과제는 예시적인 것으로, 본 발명의 기술적 사상은 이에 한정되는 것은 아니다.However, these tasks are exemplary, and the technical spirit of the present invention is not limited thereto.
본 발명의 일 관점에 의하면, 높은 연신율과 홀확장성 및 우수한 표면 특성, 및 플랜지성을 가지는 고강도 합금화 용융아연도금 강판 및 그 제조방법이 제공된다.According to one aspect of the present invention, a high-strength alloyed hot-dip galvanized steel sheet having high elongation, hole expandability, excellent surface properties, and flangeability, and a method for manufacturing the same are provided.
본 발명의 일 실시예에 의하면, 상기 고강도 합금화 용융아연도금 강판은, 중량%로, 탄소(C): 0.01% ~ 0.08% 미만, 실리콘(Si): 0.4% ~ 1.0%, 망간(Mn): 2.0% ~ 2.8%, 알루미늄(Al): 0.2% ~ 0.5%, 인(P): 0001% ~ 0.015%, 황(S): 0% 초과 ~ 0.003%, 질소(N):0% 초과 ~ 0.01%, 및 잔부는 철(Fe)과 기타 불가피한 불순물을 포함하고, 항복강도(YP): 270 MPa 이상, 인장강도(TP): 560 MPa 이상, 연신율(El): 30% 이상, 및 홀확장성(HER): 45% 이상을 만족하고, 페라이트와 마르텐사이트가 혼합된 혼합 조직을 포함할 수 있다.According to an embodiment of the present invention, the high-strength alloyed hot-dip galvanized steel sheet, by weight, carbon (C): 0.01% to less than 0.08%, silicon (Si): 0.4% to 1.0%, manganese (Mn): 2.0% to 2.8%, aluminum (Al): 0.2% to 0.5%, phosphorus (P): 0001% to 0.015%, sulfur (S): more than 0% to 0.003%, nitrogen (N): more than 0% to 0.01 %, and the balance includes iron (Fe) and other unavoidable impurities, yield strength (YP): 270 MPa or more, tensile strength (TP): 560 MPa or more, elongation (El): 30% or more, and hole expandability (HER): satisfies 45% or more, and may include a mixed structure in which ferrite and martensite are mixed.
본 발명의 일 실시예에 의하면, 상기 고강도 합금화 용융아연도금 강판은, 중량%로, 탄소(C): 0.08% ~ 0.11%, 실리콘(Si): 0.4% ~ 1.0%, 망간(Mn): 2.0% ~ 2.8%, 알루미늄(Al): 0.2% ~ 0.5%, 인(P): 0.001% ~ 0.015%, 황(S): 0% 초과 ~ 0.003%, 질소(N):0% 초과 ~ 0.01%, 및 잔부는 철(Fe)과 기타 불가피한 불순물을 포함하고, 항복강도(YP): 350 MPa 이상, 인장강도(TP): 780 MPa 이상, 연신율(El): 20% 이상, 및 홀확장성(HER): 25% 이상을 만족하고, 페라이트와 마르텐사이트가 혼합된 혼합 조직을 포함할 수 있다.According to an embodiment of the present invention, the high-strength alloyed hot-dip galvanized steel sheet is, by weight, carbon (C): 0.08% to 0.11%, silicon (Si): 0.4% to 1.0%, manganese (Mn): 2.0 % to 2.8%, aluminum (Al): 0.2% to 0.5%, phosphorus (P): 0.001% to 0.015%, sulfur (S): more than 0% to 0.003%, nitrogen (N): more than 0% to 0.01% , and the remainder contains iron (Fe) and other unavoidable impurities, yield strength (YP): 350 MPa or more, tensile strength (TP): 780 MPa or more, elongation (El): 20% or more, and hole expandability ( HER): satisfies 25% or more, and may include a mixed structure in which ferrite and martensite are mixed.
본 발명의 일 실시예에 의하면, 상기 고강도 합금화 용융아연도금 강판에서, Si/(Al + Mn) 는 0.10 ~ 0.25 범위일 수 있다.According to an embodiment of the present invention, in the high-strength alloyed hot-dip galvanized steel sheet, Si/(Al + Mn) may be in the range of 0.10 to 0.25.
본 발명의 일 실시예에 의하면, 상기 페라이트의 분율은 70% ~ 90% 범위이고, 상기 마르텐사이트의 분율은 10% ~ 30% 범위일 수 있다.According to an embodiment of the present invention, the fraction of ferrite may be in the range of 70% to 90%, and the fraction of martensite may be in the range of 10% to 30%.
본 발명의 일 실시예에 의하면, 상기 고강도 합금화 용융아연도금 강판의 제조방법은, (a) 중량%로, 중량%로, 탄소(C): 0.01% ~ 0.08% 미만, 실리콘(Si): 0.4% ~ 1.0%, 망간(Mn): 2.0% ~ 2.8%, 알루미늄(Al): 0.2% ~ 0.5%, 인(P): 0001% ~ 0.015%, 황(S): 0% 초과 ~ 0.003%, 질소(N):0% 초과 ~ 0.01%, 및 잔부는 철(Fe)과 기타 불가피한 불순물을 포함하는 열연강판을 제조하는 단계; (b) 상기 열연강판을 냉간압연하여 냉연강판을 제조하는 단계; (c) 상기 냉연강판을 770℃ ~ 820℃ 범위의 온도에서 소둔 열처리하는 단계; 및 (d) 상기 냉연강판을 다단 냉각하는 단계;를 포함할 수 있다.According to an embodiment of the present invention, the method for manufacturing the high-strength alloyed hot-dip galvanized steel sheet comprises: (a) in weight %, in weight %, carbon (C): 0.01% to less than 0.08%, silicon (Si): 0.4 % ~ 1.0%, Manganese (Mn): 2.0% ~ 2.8%, Aluminum (Al): 0.2% ~ 0.5%, Phosphorus (P): 0001% ~ 0.015%, Sulfur (S): More than 0% ~ 0.003%, Nitrogen (N): preparing a hot-rolled steel sheet containing more than 0% ~ 0.01%, and the remainder iron (Fe) and other unavoidable impurities; (b) cold-rolling the hot-rolled steel sheet to manufacture a cold-rolled steel sheet; (c) annealing the cold-rolled steel sheet at a temperature in the range of 770° C. to 820° C.; and (d) cooling the cold-rolled steel sheet in multiple stages.
본 발명의 일 실시예에 의하면, 상기 고강도 합금화 용융아연도금 강판의 제조방법은, (a) 중량%로, 탄소(C): 0.08% ~ 0.11%, 실리콘(Si): 0.4% ~ 1.0%, 망간(Mn): 2.0% ~ 2.8%, 알루미늄(Al): 0.2% ~ 0.5%, 인(P): 0.001% ~ 0.015%, 황(S): 0% 초과 ~ 0.003%, 질소(N):0% 초과 ~ 0.01%, 및 잔부는 철(Fe)과 기타 불가피한 불순물을 포함하는 열연강판을 제조하는 단계; (b) 상기 열연강판을 냉간압연하여 냉연강판을 제조하는 단계; (c) 상기 냉연강판을 770℃ ~ 820℃ 범위의 온도에서 소둔 열처리하는 단계; 및 (d) 상기 냉연강판을 다단 냉각하는 단계;를 포함할 수 있다.According to an embodiment of the present invention, the method for manufacturing the high-strength alloyed hot-dip galvanized steel sheet comprises: (a) by weight, carbon (C): 0.08% to 0.11%, silicon (Si): 0.4% to 1.0%, Manganese (Mn): 2.0% to 2.8%, Aluminum (Al): 0.2% to 0.5%, Phosphorus (P): 0.001% to 0.015%, Sulfur (S): >0% to 0.003%, Nitrogen (N): manufacturing a hot-rolled steel sheet containing more than 0% to 0.01%, and the remainder being iron (Fe) and other unavoidable impurities; (b) cold-rolling the hot-rolled steel sheet to manufacture a cold-rolled steel sheet; (c) annealing the cold-rolled steel sheet at a temperature in the range of 770° C. to 820° C.; and (d) cooling the cold-rolled steel sheet in multiple stages.
본 발명의 일 실시예에 의하면, 상기 (a) 단계는, (a-1) 상기 합금 조성을 갖는 강재를 준비하는 단계; (a-2) 상기 강재를 1,180℃ ~ 1,220℃ 범위에서 재가열하는 단계; (a-3) 상기 재가열된 강재를 880℃ ~ 950℃ 범위의 마무리압연 종료온도에서 열간 마무리 압연하여 열연강판을 제조하는 단계; 및 (a-4) 상기 열연강판을 400℃ ~ 700℃ 범위에서 권취하는 단계를 포함할 수 있다.According to an embodiment of the present invention, the step (a) comprises the steps of: (a-1) preparing a steel material having the alloy composition; (a-2) reheating the steel in the range of 1,180°C to 1,220°C; (a-3) preparing a hot-rolled steel sheet by hot finish rolling the reheated steel at a finish rolling end temperature in the range of 880°C to 950°C; and (a-4) winding the hot-rolled steel sheet in the range of 400°C to 700°C.
본 발명의 일 실시예에 의하면, 상기 (d) 단계는, (d-1) 상기 소둔 열처리한 냉연강판을 1℃/초 ~ 10℃/초 범위의 냉각속도로 600℃ ~ 700℃ 까지 1차 냉각하는 단계; 및 (d-2) 상기 1차 냉각한 냉연강판을 10℃/초 초과 ~ 50℃/초 미만 범위의 냉각속도로 460℃ ~ 500℃ 까지 2차 냉각하는 단계;를 포함할 수 있다.According to an embodiment of the present invention, in the step (d), (d-1) the cold-rolled steel sheet subjected to the annealing heat treatment is first heated to 600° C. to 700° C. at a cooling rate in the range of 1° C./sec to 10° C./sec. cooling; and (d-2) secondary cooling of the firstly cooled cold-rolled steel sheet to 460° C. to 500° C. at a cooling rate in the range of more than 10° C./sec to less than 50° C./sec.
본 발명의 일 실시예에 의하면, 상기 (d) 단계를 수행한 후에, (e) 상기 냉연강판을 용융아연 도금욕에 침지하여 460℃ ~ 500℃의 온도에서 용융아연도금을 수행하는 단계;를 더 포함할 수 있다.According to an embodiment of the present invention, after performing step (d), (e) immersing the cold-rolled steel sheet in a hot-dip galvanizing bath to perform hot-dip galvanizing at a temperature of 460°C to 500°C; may include more.
본 발명의 일 실시예에 의하면, 상기 (e) 단계를 수행한 후에, (f) 상기 용융아연 도금된 냉연강판을 490℃ ~ 530℃의 범위의 온도에서 합금화 열처리를 수행하는 단계;를 더 포함할 수 있다.According to an embodiment of the present invention, after performing step (e), (f) performing an alloying heat treatment on the hot-dip galvanized cold-rolled steel sheet at a temperature in the range of 490°C to 530°C; further comprising can do.
본 발명의 기술적 사상에 의할 경우, 고강도 합금화 용융아연도금 강판은 590 MPa급에서 30% 이상의 연신율과 45% 이상의 홀확장성을 확보할 수 있고, 780 MPa급에서 연신율 20% 이상의 연신율과, 25% 이상의 홀확장성을 확보할 수 있고, 또한 우수한 표면특성을 가진 도금강판을 제공할 수 있다. 따라서, 종래의 이상조직강에 비하여 성형성이 향상되어 복잡한 형상의 부품에 적용할 수 있다.According to the technical concept of the present invention, the high-strength alloyed hot-dip galvanized steel sheet can secure an elongation of 30% or more and a hole expandability of 45% or more at a 590 MPa class, an elongation of 20% or more at a 780 MPa class, and 25 % or more can be secured, and a plated steel sheet having excellent surface properties can be provided. Therefore, the formability is improved compared to the conventional abnormal-structured steel, and thus it can be applied to parts having a complex shape.
상술한 본 발명의 효과들은 예시적으로 기재되었고, 이러한 효과들에 의해 본 발명의 범위가 한정되는 것은 아니다.The above-described effects of the present invention have been described by way of example, and the scope of the present invention is not limited by these effects.
도 1은 본 발명의 실시예에 따른 고강도 합금화 용융아연도금 강판의 제조방법을 개략적으로 나타낸 공정 순서도이다.
도 2는 본 발명의 실시예에 따른 고강도 합금화 용융아연도금 강판의 표면 결함을 설명하는 사진들이다.1 is a process flowchart schematically illustrating a method of manufacturing a high-strength alloyed hot-dip galvanized steel sheet according to an embodiment of the present invention.
2 is a photograph illustrating surface defects of a high-strength alloyed hot-dip galvanized steel sheet according to an embodiment of the present invention.
이하, 첨부된 도면을 참조하여 본 발명의 바람직한 실시예를 상세히 설명하기로 한다. 본 발명의 실시예들은 당해 기술 분야에서 통상의 지식을 가진 자에게 본 발명의 기술적 사상을 더욱 완전하게 설명하기 위하여 제공되는 것이며, 하기 실시예는 여러 가지 다른 형태로 변형될 수 있으며, 본 발명의 기술적 사상의 범위가 하기 실시예에 한정되는 것은 아니다. 오히려, 이들 실시예는 본 개시를 더욱 충실하고 완전하게 하고, 당업자에게 본 발명의 기술적 사상을 완전하게 전달하기 위하여 제공되는 것이다. 본 명세서에서 동일한 부호는 시종 동일한 요소를 의미한다. 나아가, 도면에서의 다양한 요소와 영역은 개략적으로 그려진 것이다. 따라서, 본 발명의 기술적 사상은 첨부한 도면에 그려진 상대적인 크기나 간격에 의해 제한되지 않는다. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments of the present invention are provided to more completely explain the technical idea of the present invention to those of ordinary skill in the art, and the following examples may be modified in various other forms, The scope of the technical idea is not limited to the following examples. Rather, these embodiments are provided so as to more fully and complete the present disclosure, and to fully convey the technical spirit of the present invention to those skilled in the art. In this specification, the same reference numerals refer to the same elements throughout. Furthermore, various elements and regions in the drawings are schematically drawn. Accordingly, the technical spirit of the present invention is not limited by the relative size or spacing drawn in the accompanying drawings.
본 발명은 높은 연신율과 홀확장성 및 우수한 표면 특성, 및 플랜지성을 가지는 고강도 합금화 용융아연도금 강판 및 그 제조방법을 제공하는 것이다.An object of the present invention is to provide a high-strength hot-dip galvanized steel sheet having high elongation, hole expansion, excellent surface properties, and flangeability, and a method for manufacturing the same.
본 발명의 기술적 사상에 따르면, 일반적인 이상조직강의 특성에 비해 향상된 연신율과 플랜지성을 확보하기 위하여, 페라이트의 분율을 확보하면서 동시에 페라이트 경도를 상향시켜 마르텐사이트 상과의 경도차를 감소시킨다. 이를 위하여, 실리콘(Si)을 첨가하여 페라이트 내부의 탄소를 결정립계로 이동시켜 청정한 페라이트를 확보하여 연신율을 상향시키고, 또한 페라이트 내의 고용강화 효과를 발생시켜 페라이트의 경도를 상향시킬 수 있다. 이에 따라, 페라이트와 마르텐사이트 사이의 상간 경도차를 감소시켜 연신율 증가 및 플랜지성 향상을 제공할 수 있다.According to the technical idea of the present invention, in order to secure an improved elongation and flangeability compared to the characteristics of general abnormal structure steel, the hardness difference with the martensite phase is reduced by increasing the ferrite hardness while securing the fraction of ferrite. To this end, silicon (Si) is added to move carbon inside the ferrite to the grain boundary to secure clean ferrite to increase the elongation, and also to increase the hardness of the ferrite by generating a solid solution strengthening effect in the ferrite. Accordingly, it is possible to provide an increase in elongation and improvement in flangeability by reducing the difference in hardness between the phases of ferrite and martensite.
다만, 실리콘을 다량 첨가하면, 냉연 열처리 공정에서 실리콘 리치(Si-Rich) 산화막이 강판 표면에 전체적으로 치밀하게 형성되어 도금 공정과 합금화 공정에 나쁜 영향을 끼치게 되어, 결과적으로 미도금 또는 미합금 등의 결함을 유발할 수 있다. 이러한 문제점을 해결하기 위하여, 페라이트 안정화 원소이며 실리콘에 비하여 산화성이 강한 알루미늄을 더 첨가함으로써 실리콘 과잉 산화막 형성을 억제하여, 표면에 망간 리치(Mn-Rich) 산화막을 형성하여, 이에 따라 연신율 감소를 최소화하고 동시에 강판의 표면 특성이 향상된 강판을 제공할 수 있다.However, if a large amount of silicon is added, a silicon-rich (Si-Rich) oxide film is densely formed on the entire surface of the steel sheet in the cold rolling heat treatment process, adversely affecting the plating process and the alloying process. may cause defects. In order to solve this problem, a manganese-rich (Mn-Rich) oxide film is formed on the surface by adding more aluminum, which is a ferrite stabilizing element and has stronger oxidation properties than silicon, to suppress the formation of an excessive silicon oxide film, thereby minimizing the reduction in elongation. and at the same time, it is possible to provide a steel sheet having improved surface properties of the steel sheet.
이하에서는 본 발명의 기술적 사상에 따른 고강도 합금화 용융아연도금 강판에 대하여 설명하기로 한다.Hereinafter, a high-strength alloyed hot-dip galvanized steel sheet according to the technical spirit of the present invention will be described.
본 발명에 따른 고강도 합금화 용융아연도금 강판에 포함되는 각 성분의 역할 및 그 함량에 대하여 설명하면 다음과 같다. 이때, 성분 원소의 함유량은 모두 강판 전체에 대한 중량%를 의미한다.The role and content of each component included in the high-strength alloyed hot-dip galvanized steel sheet according to the present invention will be described as follows. At this time, the content of the component elements all mean weight % with respect to the entire steel sheet.
탄소(C): 0.01% ~ 0.11%Carbon (C): 0.01% to 0.11%
탄소는 강도에 기여하는 원소로, 오스테나이트에 고용되어 최종 냉각후 마르텐사이트의 강도 상승을 유발하여 재질 강도 증가에 효과가 있다. 탄소의 함량이 0.01% 미만인 경우에는, 강도 상승효과가 부족하게 된다. 탄소의 함량이 0.11%를 초과하는 경우에는, 마르텐사이트 강도를 상승하며 페라이트 및 마르텐사이트간 상간 경도차를 증가시켜 홀확장성의 저하를 일으키고, 탄소 당량을 증가하여 점용접성이 저하될 수 있다. 따라서, 탄소의 함량을 강판 전체 중량의 0.01% ~ 0.11%로 첨가하는 것이 바람직하다.Carbon is an element that contributes to strength. It is dissolved in austenite and causes an increase in the strength of martensite after final cooling, which is effective in increasing material strength. When the carbon content is less than 0.01%, the strength-increasing effect is insufficient. When the content of carbon exceeds 0.11%, the martensite strength is increased and the hardness difference between the ferrite and martensite phases is increased to cause a decrease in hole expandability, and the carbon equivalent can be increased to lower the spot weldability. Therefore, it is preferable to add the carbon content in an amount of 0.01% to 0.11% of the total weight of the steel sheet.
실리콘(Si): 0.4% ~ 1.0%Silicon (Si): 0.4% to 1.0%
실리콘은 페라이트 안정화 원소이며, 페라이트 내에 고용 되어 페라이트 강도를 증가시키고, 페라이트 내 전위 밀도를 증가시켜 가공경화지수를 증가시킬 수 있다. 실리콘의 함량이 0.4% 미만인 경우에는, 강도와 연신율이 저하될 수 있다. 실리콘의 함량이 1.0%를 초과하는 경우에는, 강판 표면에 실리콘계 산화물을 형성하여 표면 특성과 도금 특성이 저하될 수 있다. 따라서, 실리콘의 함량을 강판 전체 중량의 0.4% ~ 1.0%로 첨가하는 것이 바람직하다.Silicon is a ferrite stabilizing element, and it is dissolved in ferrite to increase ferrite strength and increase dislocation density in ferrite to increase work hardening index. When the content of silicon is less than 0.4%, strength and elongation may be reduced. When the content of silicon exceeds 1.0%, a silicon-based oxide is formed on the surface of the steel sheet, and surface properties and plating properties may be deteriorated. Therefore, it is preferable to add the content of silicon in an amount of 0.4% to 1.0% of the total weight of the steel sheet.
망간(Mn): 2.0% ~ 2.8%Manganese (Mn): 2.0% to 2.8%
망간은 소입성 원소로써 냉각 중 오스테나이트 안정화함으로써 펄라이트 및 베이나이트의 제3상이 형성되는 것을 억제함으로써, 낮은 냉각속도에서도 페라이트와 마르텐사이트의 이상 분리를 용이하게 한다. 망간의 함량이 2.0% 미만인 경우에는, 제3상의 형성에 따라 강도가 저하될 수 있다. 망간의 함량이 2.8%를 초과하는 경우에는, 아주 낮은 냉각속도에서도 제3상의 형성을 억제함으로써 열연재의 강도를 극대화하여, 냉간압연시 압연 부하를 발생시킬 수 있다. 또한 망간이 농화된 밴드조직을 형성함으로써 굽힘성의 저하 요인이 될 수 있다. 따라서, 망간의 함량을 강판 전체 중량의 2.0% ~ 2.8%로 첨가하는 것이 바람직하다.Manganese as a hardenable element suppresses the formation of the third phase of pearlite and bainite by stabilizing austenite during cooling, thereby facilitating the ideal separation of ferrite and martensite even at a low cooling rate. When the manganese content is less than 2.0%, the strength may be reduced due to the formation of the third phase. When the manganese content exceeds 2.8%, the strength of the hot-rolled material is maximized by suppressing the formation of the third phase even at a very low cooling rate, thereby generating a rolling load during cold rolling. In addition, by forming a band structure in which manganese is concentrated, it may be a factor of deterioration of bendability. Therefore, it is preferable to add the manganese content in an amount of 2.0% to 2.8% of the total weight of the steel sheet.
알루미늄(Al): 0.2% ~ 0.5%Aluminum (Al): 0.2% to 0.5%
알루미늄은 페라이트 청정화 원소이며, 페라이트 내 탄화물 석출을 억제하여 페라이트의 연성을 향상시킬 수 있다. 도금재의 경우에는, 산화력이 강하여 강판 내부에서 알루미늄이 먼저 산화되어, 표층부의 실리콘계 산화물 형성을 억제하게 되어, 도금 특성을 향상시킬 수 있다. 알루미늄의 함량이 0.2% 미만인 경우에는, 도금 특성 및 연신율 향상에 대한 효과가 부족할 수 있다. 알루미늄의 함량이 0.5% 를 초과하는 경우에는, A1, A3 변태점을 상승시켜, 소둔역 초기 오스테나이트 분율 확보를 위하여 고온 소둔을 수행해야 될 수 있다. 따라서, 알루미늄의 함량을 강판 전체 중량의 0.2% ~ 0.5%로 첨가하는 것이 바람직하다.Aluminum is a ferrite cleaning element, and can improve ductility of ferrite by suppressing carbide precipitation in ferrite. In the case of the plating material, aluminum is first oxidized inside the steel sheet due to strong oxidizing power, thereby suppressing the formation of silicon-based oxide in the surface layer portion, thereby improving plating properties. When the content of aluminum is less than 0.2%, the effect on improving plating properties and elongation may be insufficient. When the content of aluminum exceeds 0.5%, it may be necessary to perform high-temperature annealing in order to increase the A1 and A3 transformation points to secure the initial austenite fraction in the annealing region. Therefore, it is preferable to add the content of aluminum in an amount of 0.2% to 0.5% of the total weight of the steel sheet.
인(P): 0.001% ~ 0.015%Phosphorus (P): 0.001% to 0.015%
인은 고용강화 효과가 큰 원소로 소재 강도를 향상시킬 수 있다. 인의 함량이 0.001% 미만인 경우에는, 강도 증가 효과가 적고 탈인을 위한 공정 비용 증가가 크게 될 수 있다. 인의 함량이 0.015% 를 초과하는 경우에는, 인이 입계에 편석하여 강의 인성 및 용접성을 저하시킬 수 있다. 따라서, 인의 함량을 강판 전체 중량의 0.001% 초과 ~ 0.015%로 제한하는 것이 바람직하다.Phosphorus is an element with a large solid solution strengthening effect and can improve material strength. When the phosphorus content is less than 0.001%, the effect of increasing the strength is small and the process cost for dephosphorization may be increased significantly. When the content of phosphorus exceeds 0.015%, phosphorus may segregate at grain boundaries to deteriorate the toughness and weldability of steel. Therefore, it is preferable to limit the phosphorus content to more than 0.001% to 0.015% of the total weight of the steel sheet.
황(S): 0% 초과 ~ 0.003%Sulfur (S): >0% to 0.003%
황은 강의 제조 시 불가피하게 함유되는 원소로서, 망간과 결합하여 MnS 개재물을 형성하여 굽힘 등 부품 성형성을 저해할 수 있다. 따라서, 황의 함량을 강판 전체 중량의 0% 초과 ~ 0.003%로 제한하는 것이 바람직하다.Sulfur is an element that is inevitably contained in the manufacture of steel, and may be combined with manganese to form MnS inclusions, thereby inhibiting part formability such as bending. Therefore, it is preferable to limit the sulfur content to more than 0% to 0.003% of the total weight of the steel sheet.
질소(N): 0% 초과 ~ 0.01%Nitrogen (N): >0% to 0.01%
질소는 AlN 형성 등을 통한 연주 시 크랙이 발생할 위험성이 크게 증가될 수 있다. 따라서, 질소의 함량을 강판 전체 중량의 0% 초과 ~ 0.01%로 제한하는 것이 바람직하다.Nitrogen may greatly increase the risk of cracking when playing through AlN formation. Therefore, it is preferable to limit the nitrogen content to more than 0% to 0.01% of the total weight of the steel sheet.
상기 고강도 합금화 용융아연도금 강판의 나머지 성분은 철(Fe)이다. 다만, 통상의 제강 과정에서는 원료 또는 주위 환경으로부터 의도되지 않은 불순물들이 불가피하게 혼입될 수 있으므로, 이를 배제할 수는 없다. 이들 불순물들은 통상의 제조과정의 기술자라면 누구라도 알 수 있는 것이기 때문에 그 모든 내용을 본 명세서에서 특별히 언급하지는 않는다.The remaining component of the high-strength alloyed hot-dip galvanized steel sheet is iron (Fe). However, since unintended impurities from raw materials or the surrounding environment may inevitably be mixed in the normal steelmaking process, it cannot be excluded. Since these impurities are known to any person skilled in the art of manufacturing processes, all details thereof are not specifically mentioned in the present specification.
본 발명의 일실시예에 따른 고강도 합금화 용융아연도금 강판은, 0.01% ~ 0.08% 미만의 탄소 함량을 가지는 강판으로서, 중량%로, 탄소(C): 0.01% ~ 0.08% 미만, 실리콘(Si): 0.4% ~ 1.0%, 망간(Mn): 2.0% ~ 2.8%, 알루미늄(Al): 0.2% ~ 0.5%, 인(P): 0001% ~ 0.015%, 황(S): 0% 초과 ~ 0.003%, 질소(N):0% 초과 ~ 0.01%, 및 잔부는 철(Fe)과 기타 불가피한 불순물을 포함한다.The high-strength alloyed hot-dip galvanized steel sheet according to an embodiment of the present invention is a steel sheet having a carbon content of 0.01% to less than 0.08%, by weight, carbon (C): 0.01% to less than 0.08%, silicon (Si) : 0.4% to 1.0%, Manganese (Mn): 2.0% to 2.8%, Aluminum (Al): 0.2% to 0.5%, Phosphorus (P): 0001% to 0.015%, Sulfur (S): More than 0% to 0.003 %, nitrogen (N): more than 0% to 0.01%, and the balance includes iron (Fe) and other unavoidable impurities.
이때, 상기 고강도 합금화 용융아연도금 강판에서, Si/(Al + Mn) 는 0.10 ~ 0.25 범위일 수 있다. 상기 범위에서 상기 고강도 합금화 용융아연도금 강판의 연신율, 성형성, 표면 특성이 우수하게 나타나게 된다. In this case, in the high-strength alloyed hot-dip galvanized steel sheet, Si/(Al + Mn) may be in the range of 0.10 to 0.25. Within the above range, the elongation, formability, and surface properties of the high-strength alloyed hot-dip galvanized steel sheet are excellent.
상기 고강도 합금화 용융아연도금 강판은, 0.01% ~ 0.08% 미만의 탄소 함량을 가지는 강판으로서, 항복강도(YP): 270 MPa 이상, 인장강도(TP): 560 MPa 이상, 연신율(El): 30% 이상, 및 홀확장성(HER): 45% 이상을 만족할 수 있다. 상기 고강도 합금화 용융아연도금 강판은, 항복강도(YP): 270 MPa ~ 370 MPa, 인장강도(TP): 560 MPa ~ 650 MPa, 연신율(El): 30% ~ 40%, 및 홀확장성(HER): 45% ~ 60%를 만족할 수 있다.The high-strength alloyed hot-dip galvanized steel sheet is a steel sheet having a carbon content of 0.01% to less than 0.08%, yield strength (YP): 270 MPa or more, tensile strength (TP): 560 MPa or more, elongation (El): 30% or more, and hole expandability (HER): 45% or more may be satisfied. The high-strength alloyed hot-dip galvanized steel sheet has, yield strength (YP): 270 MPa to 370 MPa, tensile strength (TP): 560 MPa to 650 MPa, elongation (El): 30% to 40%, and hole expandability (HER) ): 45% to 60% can be satisfied.
또한, 본 발명의 일실시예에 따른 고강도 합금화 용융아연도금 강판은, 0.08% ~ 0.11%의 탄소 함량을 가지는 고탄소 강판으로서, 중량%로, 탄소(C): 0.08% ~ 0.11%, 실리콘(Si): 0.4% ~ 1.0%, 망간(Mn): 2.0% ~ 2.8%, 알루미늄(Al): 0.2% ~ 0.5%, 인(P): 0.001% ~ 0.015%, 황(S): 0% 초과 ~ 0.003%, 질소(N):0% 초과 ~ 0.01%, 및 잔부는 철(Fe)과 기타 불가피한 불순물을 포함한다.In addition, the high-strength alloyed hot-dip galvanized steel sheet according to an embodiment of the present invention is a high-carbon steel sheet having a carbon content of 0.08% to 0.11%, in weight%, carbon (C): 0.08% to 0.11%, silicon ( Si): 0.4% to 1.0%, Manganese (Mn): 2.0% to 2.8%, Aluminum (Al): 0.2% to 0.5%, Phosphorus (P): 0.001% to 0.015%, Sulfur (S): More than 0% ~ 0.003%, nitrogen (N): more than 0% ~ 0.01%, and the balance contains iron (Fe) and other unavoidable impurities.
이때, 상기 고강도 합금화 용융아연도금 강판에서, Si/(Al + Mn) 비율은 0.10 ~ 0.25 일 수 있다. 상기 범위에서 상기 고강도 합금화 용융아연도금 강판의 연신율, 성형성, 표면 특성이 우수하게 나타나게 된다. 이와 같은, 비율에 의하여, 연신율 및 성형성이 향상되고, 표면 특성이 향상될 수 있다.In this case, in the high-strength alloyed hot-dip galvanized steel sheet, the Si/(Al + Mn) ratio may be 0.10 to 0.25. Within the above range, the elongation, formability, and surface properties of the high-strength alloyed hot-dip galvanized steel sheet are excellent. By such a ratio, elongation and moldability may be improved, and surface properties may be improved.
상기 고강도 합금화 용융아연도금 강판은, 0.08% ~ 0.11%의 탄소 함량을 가지는 고탄소 강판으로서, 항복강도(YP): 350 MPa 이상, 인장강도(TP): 780 MPa 이상, 연신율(El): 20% 이상, 및 홀확장성(HER): 25% 이상을 만족할 수 있다. 상기 고강도 합금화 용융아연도금 강판은, 항복강도(YP): 350 MPa ~ 450 MPa, 인장강도(TP): 780 MPa ~ 880 MPa, 연신율(El): 20% ~ 25%, 및 홀확장성(HER): 25% ~ 35%를 만족할 수 있다.The high-strength alloyed hot-dip galvanized steel sheet is a high-carbon steel sheet having a carbon content of 0.08% to 0.11%, yield strength (YP): 350 MPa or more, tensile strength (TP): 780 MPa or more, elongation (El): 20 % or more, and hole expandability (HER): 25% or more. The high-strength alloyed hot-dip galvanized steel sheet has, yield strength (YP): 350 MPa to 450 MPa, tensile strength (TP): 780 MPa to 880 MPa, elongation (El): 20% to 25%, and hole expandability (HER) ): 25% to 35% can be satisfied.
상기 고강도 합금화 용융아연도금 강판은, 페라이트와 마르텐사이트가 혼합된 혼합 조직을 가질 수 있다. 상기 페라이트의 분율은, 예를 들어 70% ~ 90% 범위일 수 있다. 상기 마르텐사이트의 분율은, 예를 들어 10% ~ 30% 범위일 수 있다. 상기 분율은 강판의 미세조직 사진을 이미지 분석기를 통하여 도출한 면적비율을 의미한다. 이와 같은, 상기 페라이트와 상기 마르텐사이트의 분율을 가지는 조직을 가짐으로써, 저항복 및 고연성을 확보하여 우수한 프레스 성형성을 확보할 수 있다.The high-strength alloyed hot-dip galvanized steel sheet may have a mixed structure in which ferrite and martensite are mixed. The fraction of ferrite may be, for example, in the range of 70% to 90%. The fraction of martensite may be, for example, in the range of 10% to 30%. The fraction means an area ratio derived from a microstructure photograph of a steel sheet through an image analyzer. As such, by having a structure having a fraction of the ferrite and the martensite, it is possible to secure a resistive wear and a high ductility to ensure excellent press formability.
이하, 첨부된 도면을 참조하여 본 발명에 따른 고강도 합금화 용융아연도금 강판의 제조방법에 관하여 설명한다.Hereinafter, a method for manufacturing a high-strength alloyed hot-dip galvanized steel sheet according to the present invention will be described with reference to the accompanying drawings.
고강도 합금화 용융아연도금 강판의 제조방법Manufacturing method of high-strength alloyed hot-dip galvanized steel sheet
도 1은 본 발명의 실시예에 따른 고강도 합금화 용융아연도금 강판의 제조방법을 개략적으로 나타낸 공정 순서도이다.1 is a process flowchart schematically illustrating a method of manufacturing a high-strength alloyed hot-dip galvanized steel sheet according to an embodiment of the present invention.
도 1을 참조하면, 본 발명의 실시예에 따른 고강도 합금화 용융아연도금 강판의 제조방법은, 상기 조성의 강재를 이용하여 열연강판을 제조하는 단계(S110), 상기 열연강판을 냉간 압연하여 냉연강판을 제조하는 단계(S120); 상기 냉연강판을 소둔 열처리하는 단계(S130); 및 상기 냉연강판을 다단 냉각하는 단계(S140);를 포함한다.Referring to FIG. 1 , the method for manufacturing a high-strength alloyed hot-dip galvanized steel sheet according to an embodiment of the present invention includes manufacturing a hot-rolled steel sheet using the steel of the composition (S110), and cold-rolling the hot-rolled steel sheet to obtain a cold-rolled steel sheet. manufacturing (S120); annealing the cold-rolled steel sheet (S130); and cooling the cold-rolled steel sheet in multiple stages (S140).
또한, 상기 고강도 합금화 용융아연도금 강판의 제조방법은, 상기 냉연강판을 용융아연 도금하는 단계(S150)를 더 포함할 수 있다.In addition, the method for manufacturing the high-strength alloyed hot-dip galvanized steel sheet may further include hot-dip galvanizing the cold-rolled steel sheet (S150).
또한, 상기 고강도 합금화 용융아연도금 강판의 제조방법은, 상기 용융아연 도금하는 단계를 수행한 후에 상기 용융아연 도금된 냉연강판을 합금화 열처리하는 단계(S160)를 더 포함할 수 있다. In addition, the method for manufacturing the high-strength alloyed hot-dip galvanized steel sheet may further include an alloying heat treatment step (S160) of the hot-dip galvanized cold-rolled steel sheet after performing the hot-dip galvanizing step.
열연강판 제조단계(S110)Hot-rolled steel sheet manufacturing step (S110)
상기 합금 조성을 갖는 강괴 또는 강 슬라브와 같은 강재를 준비한다. 상기 강재는, 중량%로, 탄소(C): 0.01% ~ 0.08% 미만, 실리콘(Si): 0.4% ~ 1.0%, 망간(Mn): 2.0% ~ 2.8%, 알루미늄(Al): 0.2% ~ 0.5%, 인(P): 0001% ~ 0.015%, 황(S): 0% 초과 ~ 0.003%, 질소(N):0% 초과 ~ 0.01%, 및 잔부는 철(Fe)과 기타 불가피한 불순물을 포함할 수 있다. 또는, 상기 강재는, 중량%로, 탄소(C): 0.08% ~ 0.11%, 실리콘(Si): 0.4% ~ 1.0%, 망간(Mn): 2.0% ~ 2.8%, 알루미늄(Al): 0.2% ~ 0.5%, 인(P): 0.001% ~ 0.015%, 황(S): 0% 초과 ~ 0.003%, 질소(N):0% 초과 ~ 0.01%, 및 잔부는 철(Fe)과 기타 불가피한 불순물을 포함할 수 있다.A steel material such as a steel ingot or steel slab having the above alloy composition is prepared. The steel is, by weight, carbon (C): 0.01% to less than 0.08%, silicon (Si): 0.4% to 1.0%, manganese (Mn): 2.0% to 2.8%, aluminum (Al): 0.2% to 0.5%, phosphorus (P): 0001% to 0.015%, sulfur (S): more than 0% to 0.003%, nitrogen (N): more than 0% to 0.01%, and the balance is iron (Fe) and other unavoidable impurities may include Alternatively, the steel material, in weight%, carbon (C): 0.08% to 0.11%, silicon (Si): 0.4% to 1.0%, manganese (Mn): 2.0% to 2.8%, aluminum (Al): 0.2% to 0.5%, phosphorus (P): 0.001% to 0.015%, sulfur (S): more than 0% to 0.003%, nitrogen (N): more than 0% to 0.01%, and the balance being iron (Fe) and other unavoidable impurities may include
상기 강재를, 예를 들어 1,180℃ ~ 1,220℃ 범위의 재가열 온도(Slab Reheating Temperature, SRT)에서 재가열한다. 이러한 재가열을 통해, 주조 조직을 파괴하여 오스테나이징 처리를 실시하며 이때 주조 시 편석된 성분의 재고용 및 석출물의 재고용이 발생할 수 있다. 상기 재가열 온도가 1,180℃ 미만인 경우에는, 열간압연하중이 급격히 증가하는 문제가 발생할 수 있다. 상기 재가열 온도가 1,220℃를 초과하는 경우에는, 표면 스케일량이 증가하여 재료의 손실로 이어질 수 있고, 에너지가 낭비될 수 있다.The steel is reheated, for example, at a reheating temperature (Slab Reheating Temperature, SRT) in the range of 1,180°C to 1,220°C. Through such reheating, the austenizing treatment is performed by destroying the cast structure, and at this time, re-dissolution of segregated components and re-dissolution of precipitates may occur during casting. When the reheating temperature is less than 1,180°C, a problem in which the hot rolling load is rapidly increased may occur. When the reheating temperature exceeds 1,220°C, the amount of surface scale may increase, leading to loss of material, and energy may be wasted.
상기 재가열 후 통상의 방법으로 열간압연을 행하고, 예를 들어 880℃ ~ 950℃ 범위의 마무리압연 종료온도(finish delivery temperature, FDT)에서 열간 마무리 압연을 수행하여 열연강판을 제조할 수 있다. 상기 마무리 압연 종료온도가 880℃ 미만인 경우에는, 페라이트와 펄라이트의 밴드상 조직(band structure)이 생성될 수 있다. 상기 마무리 압연 종료온도가 950℃를 초과할 경우에는, 스케일 생성의 증가되고, 결정 입경이 조대화되어, 조직의 미세 균일화가 어려울 수 있다.After the reheating, hot rolling is performed in a conventional manner, and, for example, hot finish rolling is performed at a finish delivery temperature (FDT) in the range of 880° C. to 950° C. to manufacture a hot-rolled steel sheet. When the finish rolling end temperature is less than 880° C., a band structure of ferrite and pearlite may be formed. When the finish rolling end temperature exceeds 950° C., scale generation is increased, and the grain size is coarsened, so that it may be difficult to finely homogenize the structure.
이어서, 상기 열연강판을, 예를 들어 400℃ ~ 700℃ 범위의 권취온도까지 냉각한다. 상기 냉각은 공냉 또는 수냉 모두 가능하며, 예를 들어 5℃/초 ~ 150℃/초의 냉각속도로 냉각할 수 있다. 상기 냉각은 공랭 또는 수냉으로 수행될 수 있다. 상기 냉각은 권취 온도까지 냉각하는 것이 바람직하다.Then, the hot-rolled steel sheet is cooled to a coiling temperature in the range of, for example, 400°C to 700°C. The cooling may be either air cooling or water cooling, for example, cooling at a cooling rate of 5° C./sec to 150° C./sec. The cooling may be performed by air cooling or water cooling. Preferably, the cooling is performed to a coiling temperature.
이어서, 상기 열연강판을, 예를 들어 400℃ ~ 700℃ 범위의 권취온도(coiling temperature, CT)에서 권취한다. 상기 귄취온도의 범위는 냉간 압연성, 표면 성상의 관점에서 선택할 수 있다. 상기 권취온도가 400℃ 미만인 경우에는, 마르텐사이트 등의 경질상이 과도하게 생성되어 열연강판의 재질이 과도하게 증가하여 냉간압연 시 압연 부하가 현저하게 증가 할 수 있다. 상기 권취 온도가 700℃를 초과할 경우에는, 페라이트-펄라이트 밴드구조가 심해져 최종 제품의 미세조직의 불균일성을 초래할 수 있다. 상기 권취된 열연강판은 페라이트, 펄라이트 및 마르텐사이트가 홍합된 혼합조직을 가질 수 있다.Then, the hot-rolled steel sheet is wound at a coiling temperature (CT) in the range of, for example, 400°C to 700°C. The range of the winding temperature may be selected from the viewpoint of cold rolling properties and surface properties. When the coiling temperature is less than 400 ° C., a hard phase such as martensite is excessively generated, and the material of the hot-rolled steel sheet is excessively increased, so that the rolling load during cold rolling can be significantly increased. When the coiling temperature exceeds 700° C., the ferrite-pearlite band structure becomes severe and may result in non-uniformity of the microstructure of the final product. The wound hot-rolled steel sheet may have a mixed structure in which ferrite, pearlite and martensite are musseled.
냉연강판 제조단계(S120)Cold-rolled steel sheet manufacturing step (S120)
상기 열연강판을 산으로 세정하는 산세 처리를 수행한다. 이어서, 상기 산세 처리된 열연강판을, 예를 들어 40% ~ 80%의 평균 압하율로 냉간압연을 실시하여 냉연강판을 형성한다. 상기 평균 압하율이 높을수록, 조직 미세화 효과로 인한 성형성이 상승되는 효과가 있다. 상기 평균 압하율 40% 미만인 경우에는, 균일한 미세조직을 얻기 어렵다. 상기 평균 압하율이 70%를 초과하는 경우에는, 롤 힘이 증가되어 공정부하가 증가된다.A pickling treatment of washing the hot-rolled steel sheet with acid is performed. Next, the pickling-treated hot-rolled steel sheet is subjected to cold rolling at an average reduction ratio of 40% to 80%, for example, to form a cold-rolled steel sheet. As the average reduction ratio is higher, there is an effect of increasing the formability due to the effect of refining the tissue. When the average reduction ratio is less than 40%, it is difficult to obtain a uniform microstructure. When the average reduction ratio exceeds 70%, the roll force is increased to increase the process load.
소둔 열처리 단계(S130)Annealing heat treatment step (S130)
상기 냉연강판을 통상의 서냉각 구간이 있는 연속 소둔로에서 소둔 열처리한다. 상기 소둔 열처리는, 예를 들어 770℃ ~ 820℃의 범위의 온도에서 수행된다. 상기 소둔 열처리는 초기 오스테나이트 분율을 50% 이상 확보하기 위하여 수행된다. 상기 소둔 열처리 온도가 770℃ 미만인 경우에는, 초기 오스테나이트 분율이 확보되지 않아 강도가 확보되지 않을 수 있다. 상기 소둔 열처리 온도가 820℃를 초과하는 경우에는, 초기 오스테나이트 분율이 너무 높아져 냉각 중 펄라이트 및 베이나이트 등과 같은 제3상의 변태 제어가 어려울 수 있다.The cold-rolled steel sheet is annealed and heat treated in a continuous annealing furnace having a normal slow cooling section. The annealing heat treatment is performed, for example, at a temperature in the range of 770°C to 820°C. The annealing heat treatment is performed to secure an initial austenite fraction of 50% or more. When the annealing heat treatment temperature is less than 770° C., the initial austenite fraction may not be secured, and thus strength may not be secured. When the annealing heat treatment temperature exceeds 820° C., it may be difficult to control the transformation of a third phase such as pearlite and bainite during cooling because the initial austenite fraction is too high.
다단 냉각 단계(S140)Multi-stage cooling step (S140)
상기 소둔 열처리한 냉연강판을 다단 냉각한다. 상기 냉각하는 단계는 하기의 두 단계로 수행될 수 있다.The cold-rolled steel sheet subjected to the annealing heat treatment is cooled in multiple stages. The cooling step may be performed in the following two steps.
먼저, 상기 소둔 열처리한 냉연강판을, 예를 들어 1℃/초 ~ 10℃/초 범위의 냉각속도로, 예를 들어 600℃ ~ 700℃까지 1차 냉각한다. 상기 1차 냉각은 상대적으로 서냉 단계로 지칭될 수 있다. 상기 1차 냉각의 종료온도가 600℃ 미만인 경우에는, 원하지 않는 베이나이트의 변태가 발생할 수 있다. 상기 1차 냉각의 종료온도가 700℃를 초과하는 경우에는, 페라이트의 변태가 많이 발생하여 강도 확보가 용이하지 않을 수 있다.First, the cold-rolled steel sheet subjected to the annealing heat treatment is first cooled, for example, at a cooling rate in the range of 1°C/sec to 10°C/sec, to 600°C to 700°C. The primary cooling may be referred to as a relatively slow cooling step. When the end temperature of the primary cooling is less than 600° C., undesirable transformation of bainite may occur. When the end temperature of the primary cooling exceeds 700° C., a lot of transformation of ferrite may occur, so that it may not be easy to secure strength.
이이서, 상기 1차 냉각된 냉연강판을, 예를 들어 10℃/초 초과 ~ 50℃/초 미만의 범위의 냉각속도로, 예를 들어 460℃ ~ 500℃까지 2차 냉각한다. 상기 2차 냉각은 상대적으로 급랭 단계로 지칭될 수 있다. 상기 2차 냉각의 종료온도가 460℃ 미만인 경우에는, 강판의 온도가 낮아져서, 이후 도금 시 아연 도금욕 내에 드로스가 발생할 수 있다. 상기 2차 냉각의 종료온도가 500℃를 초과하는 경우에는, 이후 도금 시 강판의 온도가 아연 도금욕의 온도보다 높으므로, 아연 도금욕의 온도가 상승하여, 아연 증기 과잉 발생 또는 화재 등의 공정 사고가 발생할 수 있다.Then, the primary cooled cold-rolled steel sheet, for example, at a cooling rate in the range of more than 10 ℃ / sec to less than 50 ℃ / sec, for example, secondary cooling to 460 ℃ ~ 500 ℃. The secondary cooling may be referred to as a relatively quenching step. When the end temperature of the secondary cooling is less than 460° C., the temperature of the steel sheet is lowered, and dross may be generated in the galvanizing bath during subsequent plating. When the end temperature of the secondary cooling exceeds 500° C., the temperature of the steel sheet during subsequent plating is higher than the temperature of the galvanizing bath, so the temperature of the galvanizing bath increases, resulting in excessive zinc vapor generation or fire. Accidents may occur.
이후 과시효 대에서는, 안정된 페라이트와 오스테나이트가 분리된 구조가 유지되고, 이후 아연 도금 이후 최종 냉각 시 오스테나이트가 마르텐사이트로 변태하게 되어, 최종 조직은 페라이트와 마르텐사이트가 혼합된 혼합 조직을 형성할 수 있다.After that, in the over-aging zone, a stable structure in which ferrite and austenite are separated is maintained, and after galvanizing, austenite is transformed into martensite during final cooling after galvanizing, and the final structure forms a mixed structure of ferrite and martensite can do.
상기 강판의 표면품질은 일반적으로 로내 이슬점(Dew Point)이 -30℃ ~ -50℃ 수준으로 유지되고, 이 구간에서 알루미늄 첨가 효과로 용융아연 도금단계를 수행하기 전에 상기 강판의 표면에 실리콘-리치(Si-Rich) 산화물 형성을 억제하게 되고, 또한 합금화 단계를 수행할 때 부하를 줄일 수 있으며, 미려한 표면 품질을 확보할 수 있다.As for the surface quality of the steel sheet, the dew point in the furnace is generally maintained at a level of -30°C to -50°C, and in this section, silicon-rich on the surface of the steel sheet before performing the hot-dip galvanizing step due to the effect of adding aluminum. (Si-Rich) oxide formation is suppressed, the load can be reduced when performing the alloying step, and beautiful surface quality can be secured.
또한, 상기 고강도 합금화 용융아연도금 강판은 냉연강판 외에도, 용융아연 도금강판 및 합금화 용융아연 도금강판으로 제조될 수 있다.In addition, the high-strength alloyed hot-dip galvanized steel sheet may be manufactured as a hot-dip galvanized steel sheet and an alloyed hot-dip galvanized steel sheet in addition to the cold-rolled steel sheet.
용융아연 도금단계(S150)Hot-dip galvanizing step (S150)
용융아연 도금단계(S150)에서, 상기 냉각된 냉연강판을 용융아연 도금욕에 침지하여, 상기 냉연강판 표면에 용융아연 도금층이 형성되어 용융아연 도금강판을 형성할 수 있다. 상기 냉연강판을, 예를 들어 460℃ ~ 500℃의 범위의 온도에서 30초 ~ 100초 범위의 시간 동안 유지하여 용융아연 도금을 수행한다. 이어서, 1℃/초 ~ 100℃/초의 냉각속도로 상온으로 냉각시켜 용융아연 도금강판을 제조할 수 있다.In the hot-dip galvanizing step (S150), the cooled cold-rolled steel sheet is immersed in a hot-dip galvanizing bath to form a hot-dip galvanized layer on the surface of the cold-rolled steel sheet to form a hot-dip galvanized steel sheet. Hot-dip galvanizing is performed by maintaining the cold-rolled steel sheet, for example, at a temperature in the range of 460° C. to 500° C. for a time in the range of 30 seconds to 100 seconds. Then, the hot-dip galvanized steel sheet can be manufactured by cooling to room temperature at a cooling rate of 1° C./sec to 100° C./sec.
합금화 열처리단계(S160)alloying heat treatment step (S160)
합금화 열처리 단계(S160)에서, 상기 용융아연 도금된 냉연강판을, 예를 들어 460℃ ~ 500℃의 범위의 온도에서 합금화 열처리를 실시될 수 있다. 합금화 열처리 단계(S160)는 이전의 용융아연 도금 단계를 수행한 후에 냉각하지 않고 연속하여 수행할 수 있다. 상기 조건으로 합금화 열처리시 용융아연 도금층이 안정적으로 성장되면서, 도금층의 밀착성이 우수할 수 있다. 상기 합금화 열처리 온도가 460℃ 미만인 경우에는, 합금화가 충분히 진행되지 못해 용융아연 도금층의 건전성이 저하될 수 있다. 상기 합금화 열처리 온도가 500℃를 초과하는 경우에는, 이상역 온도 구간으로 넘어가게 되면서 재질의 변화가 발생할 수 있다. 이어서, 상온으로 냉각시켜 합금화 용융아연 도금강판을 제조할 수 있다.In the alloying heat treatment step (S160), the hot-dip galvanized cold-rolled steel sheet may be subjected to an alloying heat treatment at a temperature in the range of, for example, 460°C to 500°C. The alloying heat treatment step (S160) may be performed continuously without cooling after performing the previous hot-dip galvanizing step. Under the above conditions, while the hot-dip galvanized layer is stably grown during the alloying heat treatment, the adhesion of the plating layer may be excellent. When the alloying heat treatment temperature is less than 460° C., the soundness of the hot-dip galvanizing layer may be deteriorated because alloying may not proceed sufficiently. When the alloying heat treatment temperature exceeds 500° C., the material may be changed while passing to an abnormal temperature range. Then, by cooling to room temperature, an alloyed hot-dip galvanized steel sheet can be manufactured.
실험예Experimental example
이하, 본 발명의 이해를 돕기 위해 바람직한 실험예를 제시한다. 다만, 하기의 실험예는 본 발명의 이해를 돕기 위한 것일 뿐, 본 발명이 하기의 실험예에 의해 한정되는 것은 아니다.Hereinafter, preferred experimental examples are presented to help the understanding of the present invention. However, the following experimental examples are only for helping understanding of the present invention, and the present invention is not limited by the following experimental examples.
하기 표 1의 조성(단위: 중량%)을 갖는 강을 준비하고, 상술한 바와 같은 소정의 열연 및 냉연 공정을 거쳐 실시예들과 비교예들에 따른 강판을 준비하였다. 또한, 필요한 경우, 용융아연 도금 및 합금화 열처리를 수행하였다. 표 1에서 잔부는 철(Fe) 및 기타 불가피한 불순물이다.Steel having the composition (unit: weight %) shown in Table 1 below was prepared, and steel sheets according to Examples and Comparative Examples were prepared through predetermined hot rolling and cold rolling processes as described above. In addition, if necessary, hot-dip galvanizing and alloying heat treatment were performed. The remainder in Table 1 is iron (Fe) and other unavoidable impurities.
표 1을 참조하면, 실시예들과 비교예들은 인, 황, 및 질소는 상술한 범위 내에 제한되어 있다. 실시예1, 실시예2, 비교예 1 및 비교예2는 탄소 함량이 0.01% ~ 0.08% 미만인 경우이고, 실시예3, 실시예4, 실시예5, 비교예3 및 비교예4는 0.08% ~ 0.11%인 경우이다. 또한, 비교예1 내지 비교예3은 알루미늄 함량이 0.2% ~ 0.5%에 비하여 낮은 경우이다. 비교예4는 탄소, 실리콘, 망간, 알루미늄을 본 발명의 실시예의 범위로서 가지고 있으나, 니오븀을 더 포함하는 경우이다.Referring to Table 1, in Examples and Comparative Examples, phosphorus, sulfur, and nitrogen are limited within the above-described ranges. Example 1, Example 2, Comparative Example 1 and Comparative Example 2 is a case where the carbon content is 0.01% to less than 0.08%, and Example 3, Example 4, Example 5, Comparative Example 3 and Comparative Example 4 is 0.08% It is the case of ~0.11%. In addition, in Comparative Examples 1 to 3, the aluminum content is low compared to 0.2% to 0.5%. Comparative Example 4 has carbon, silicon, manganese, and aluminum as the scope of the embodiment of the present invention, but further includes niobium.
표 2는 본 발명의 일실시예에 따른 고강도 합금화 용융아연도금 강판의 특성을 나타내는 표이다. Table 2 is a table showing the characteristics of the high-strength alloyed hot-dip galvanized steel sheet according to an embodiment of the present invention.
(MPa)yield strength
(MPa)
(MPa)The tensile strength
(MPa)
(%)elongation
(%)
(%)Hall expandability
(%)
표 2를 참조하면, 모든 실시예들은 항복강도 및 인장강도를 목표 범위로 달성하였고, 표면 상태에서도 미도금 또는 합금화 불량의 결함이 나타나지 않았다. 실시예1 내지 실시예3은 0.01% ~ 0.08% 미만의 탄소 함량을 가지는 강판으로서, 목표 범위인 30% 이상의 연신율과 45% 이상의 홀확장성을 만족하였다. 실시예4 및 실시예5는 0.08% ~ 0.11%의 탄소 함량을 가지는 고탄소 강판으로서, 목표 범위인 20% 이상의 연신율과 25% 이상의 홀확장성을 만족하였다.Referring to Table 2, all examples achieved yield strength and tensile strength within the target range, and defects of non-plating or alloying defects did not appear even in the surface state. Examples 1 to 3 were steel sheets having a carbon content of 0.01% to less than 0.08%, and satisfies the target range of elongation of 30% or more and hole expandability of 45% or more. Examples 4 and 5 were high-carbon steel sheets having a carbon content of 0.08% to 0.11%, and satisfies the target range of elongation of 20% or more and hole expandability of 25% or more.
비교예1은 0.01% ~ 0.08% 미만의 탄소 함량을 가지는 강판으로서, 목표 범위인 30% 이상의 연신율과 45% 이상의 홀확장성을 나타내지 못하였다. 비교예2는 0.01% ~ 0.08% 미만의 탄소 함량을 가지는 강판으로서, 표면 상태에서 미도금 및 합금화 불량 현상이 나타났다. 비교예3 및 비교예4는 0.08% ~ 0.11%의 탄소 함량을 가지는 고탄소 강판으로서, 목표 범위인 20% 이상의 연신율과 25% 이상의 홀확장성을 나타내지 못하였다. 비교에4의 경우에는, 니오븀 첨가에 의하여 연신율과 홀확장성이 저하된 것으로 분석된다.Comparative Example 1 was a steel sheet having a carbon content of 0.01% to less than 0.08%, and did not exhibit an elongation of 30% or more and a hole expandability of 45% or more, which are the target ranges. Comparative Example 2 is a steel sheet having a carbon content of 0.01% to less than 0.08%, and the non-plating and alloying defects were observed in the surface state. Comparative Examples 3 and 4 were high-carbon steel sheets having a carbon content of 0.08% to 0.11%, and did not exhibit elongation of 20% or more and hole expandability of 25% or more, which are the target ranges. In the case of Comparative Example 4, it is analyzed that the elongation and hole expandability are lowered by the addition of niobium.
도 2는 본 발명의 실시예에 따른 고강도 합금화 용융아연도금 강판의 표면 결함을 설명하는 사진들이다.2 is a photograph illustrating surface defects of a high-strength alloyed hot-dip galvanized steel sheet according to an embodiment of the present invention.
도 2를 참조하면, 본 발명의 실시예에서는 표면 결함이 발견되지 않았다. 비교예2로 예시된 비교예에서는, 적색 원으로 표시된 미도금 결함과 황색으로 표시된 합금화 불량 영역, 즉 미합금 영역이 나타났다. 따라서, 본 발명의 기술적 사상에 따른 고강도 합금화 용융아연도금 강판은, 비교예2로 예시된 종래의 이상조직강에 비하여 우수한 표면 특성을 가짐을 알 수 있다.Referring to FIG. 2 , no surface defects were found in the embodiment of the present invention. In the comparative example exemplified by Comparative Example 2, non-plating defects indicated by a red circle and an alloying defect region indicated in yellow, that is, an unalloyed region appeared. Therefore, it can be seen that the high-strength alloyed hot-dip galvanized steel sheet according to the technical idea of the present invention has superior surface properties compared to the conventional abnormal structure steel exemplified in Comparative Example 2.
본 발명의 기술적 사상에 따른 고강도 합금화 용융아연도금 강판은 실리콘 함량을 증가시켜, 페라이트 내의 고용 강화를 야기함으로써, 연성 페라이트 분율을 증가시켜 이에 따라 연신율을 증가시키고, 경질상인 마르텐사이트 분율을 감소시키고 페라이트와 마르텐사이트 사이의 상간 경도차를 저감시켜 홀확장성을 증가시킬 수 있다. 이러한 이상조직강의 강도는 다음과 같다.High-strength alloyed hot-dip galvanized steel sheet according to the technical idea of the present invention increases the silicon content and causes solid solution strengthening in ferrite, thereby increasing the ductile ferrite fraction and thus increasing the elongation, reducing the hard phase martensite fraction and ferrite It is possible to increase the hole expandability by reducing the interphase hardness difference between and martensite. The strength of these abnormal tissue steels is as follows.
σDP = σα fα + σM (1-fα)σ DP = σ α f α + σ M (1-f α )
여기에서, σDP 는 이상조직강의 강도, σα 는 페라이트의 강도, fα 는 페라이트의 분율, σM 는 마르텐사이트의 강도이다. 본 발명의 경우에는 페라이트의 분율(fα)이 증가되고, 마르텐사이트의 분율(1-fα)이 감소되지만, 페라이트의 강도(σα)가 실리콘 함유에 따라 증가되므로, 마르텐사이트 분율 감소에 의한 강도 감소를 보완할 수 있고, 더 나아가 전체 강도를 증가시킬 수 있다. 또한, 페라이트의 강도(σα)의 증가에 따라, 상기 페라이트와 상기 마르텐사이트 사이의 상간 경도차를 감소시켜 플랜지 특성을 향상시킬 수 있다.Here, σ DP is the strength of ideal steel, σ α is the strength of ferrite, f α is the fraction of ferrite, and σ M is the strength of martensite. In the case of the present invention, the fraction of ferrite (f α ) is increased and the fraction of martensite (1-f α ) is decreased, but the strength (σ α ) of ferrite increases with silicon content, so that the martensite fraction decreases It is possible to compensate for the decrease in strength caused by this, and further increase the overall strength. In addition, as the strength (σ α ) of the ferrite increases, it is possible to reduce the difference in hardness between the phases between the ferrite and the martensite to improve the flange properties.
이상에서 설명한 본 발명의 기술적 사상이 전술한 실시예 및 첨부된 도면에 한정되지 않으며, 본 발명의 기술적 사상을 벗어나지 않는 범위 내에서 여러 가지 치환, 변형 및 변경이 가능하다는 것은, 본 발명의 기술적 사상이 속하는 기술분야에서 통상의 지식을 가진 자에게 있어 명백할 것이다.The technical spirit of the present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is the technical spirit of the present invention that various substitutions, modifications and changes are possible within the scope without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in the art to which this belongs.
Claims (10)
항복강도(YP): 270 MPa 이상, 인장강도(TP): 560 MPa 이상, 연신율(El): 30% 이상, 및 홀확장성(HER): 45% 이상을 만족하고,
페라이트와 마르텐사이트가 혼합된 혼합 조직을 포함하는,
고강도 합금화 용융아연도금 강판.By weight%, carbon (C): 0.01% to less than 0.08%, silicon (Si): 0.4% to 1.0%, manganese (Mn): 2.0% to 2.8%, aluminum (Al): 0.2% to 0.5%, phosphorus (P): 0001% to 0.015%, sulfur (S): more than 0% to 0.003%, nitrogen (N): more than 0% to 0.01%, and the balance contains iron (Fe) and other unavoidable impurities;
Yield strength (YP): 270 MPa or more, tensile strength (TP): 560 MPa or more, elongation (El): 30% or more, and hole expansion (HER): 45% or more,
Containing a mixed structure of ferrite and martensite,
High-strength alloyed hot-dip galvanized steel sheet.
항복강도(YP): 350 MPa 이상, 인장강도(TP): 780 MPa 이상, 연신율(El): 20% 이상, 및 홀확장성(HER): 25% 이상을 만족하고,
페라이트와 마르텐사이트가 혼합된 혼합 조직을 포함하는,
고강도 합금화 용융아연도금 강판.By weight%, carbon (C): 0.08% to 0.11%, silicon (Si): 0.4% to 1.0%, manganese (Mn): 2.0% to 2.8%, aluminum (Al): 0.2% to 0.5%, phosphorus ( P): 0.001% to 0.015%, sulfur (S): more than 0% to 0.003%, nitrogen (N): more than 0% to 0.01%, and the balance contains iron (Fe) and other unavoidable impurities,
Yield strength (YP): 350 MPa or more, tensile strength (TP): 780 MPa or more, elongation (El): 20% or more, and hole expansion (HER): 25% or more,
Containing a mixed structure of ferrite and martensite,
High-strength alloyed hot-dip galvanized steel sheet.
상기 고강도 합금화 용융아연도금 강판에서, Si/(Al + Mn) 는 0.10 ~ 0.25 범위인,
고강도 합금화 용융아연도금 강판.3. The method of claim 1 or 2,
In the high-strength alloyed hot-dip galvanized steel sheet, Si / (Al + Mn) is in the range of 0.10 ~ 0.25,
High-strength alloyed hot-dip galvanized steel sheet.
상기 페라이트의 분율은 70% ~ 90% 범위이고,
상기 마르텐사이트의 분율은 10% ~ 30% 범위인,
고강도 합금화 용융아연도금 강판.3. The method of claim 1 or 2,
The fraction of ferrite is in the range of 70% to 90%,
The fraction of martensite is in the range of 10% to 30%,
High-strength alloyed hot-dip galvanized steel sheet.
(b) 상기 열연강판을 냉간압연하여 냉연강판을 제조하는 단계;
(c) 상기 냉연강판을 770℃ ~ 820℃ 범위의 온도에서 소둔 열처리하는 단계; 및
(d) 상기 냉연강판을 다단 냉각하는 단계;를 포함하는,
고강도 합금화 용융아연도금 강판의 제조방법.(a) by weight, carbon (C): 0.01% to less than 0.08%, silicon (Si): 0.4% to 1.0%, manganese (Mn): 2.0% to 2.8%, aluminum (Al): 0.2% to 0.5 %, phosphorus (P): 0001% to 0.015%, sulfur (S): more than 0% to 0.003%, nitrogen (N): more than 0% to 0.01%, and the balance contains iron (Fe) and other unavoidable impurities manufacturing a hot-rolled steel sheet;
(b) cold-rolling the hot-rolled steel sheet to manufacture a cold-rolled steel sheet;
(c) annealing the cold-rolled steel sheet at a temperature in the range of 770°C to 820°C; and
(d) step of cooling the cold-rolled steel sheet in multiple stages; including,
A method of manufacturing a high-strength alloyed hot-dip galvanized steel sheet.
(b) 상기 열연강판을 냉간압연하여 냉연강판을 제조하는 단계;
(c) 상기 냉연강판을 770℃ ~ 820℃ 범위의 온도에서 소둔 열처리하는 단계; 및
(d) 상기 냉연강판을 다단 냉각하는 단계;를 포함하는,
고강도 합금화 용융아연도금 강판의 제조방법.(a) by weight, carbon (C): 0.08% to 0.11%, silicon (Si): 0.4% to 1.0%, manganese (Mn): 2.0% to 2.8%, aluminum (Al): 0.2% to 0.5% , phosphorus (P): 0.001% to 0.015%, sulfur (S): more than 0% to 0.003%, nitrogen (N): more than 0% to 0.01%, and the balance contains iron (Fe) and other unavoidable impurities manufacturing a hot-rolled steel sheet;
(b) cold-rolling the hot-rolled steel sheet to manufacture a cold-rolled steel sheet;
(c) annealing the cold-rolled steel sheet at a temperature in the range of 770°C to 820°C; and
(d) step of cooling the cold-rolled steel sheet in multiple stages; including,
A method of manufacturing a high-strength alloyed hot-dip galvanized steel sheet.
상기 (a) 단계는,
(a-1) 상기 합금 조성을 갖는 강재를 준비하는 단계;
(a-2) 상기 강재를 1,180℃ ~ 1,220℃ 범위에서 재가열하는 단계;
(a-3) 상기 재가열된 강재를 880℃ ~ 950℃ 범위의 마무리압연 종료온도에서 열간 마무리 압연하여 열연강판을 제조하는 단계; 및
(a-4) 상기 열연강판을 400℃ ~ 700℃ 범위에서 권취하는 단계를 포함하는,
고강도 합금화 용융아연도금 강판의 제조방법.7. The method according to claim 5 or 6,
The step (a) is,
(a-1) preparing a steel material having the alloy composition;
(a-2) reheating the steel in the range of 1,180°C to 1,220°C;
(a-3) preparing a hot-rolled steel sheet by hot finish rolling the reheated steel at a finish rolling end temperature in the range of 880°C to 950°C; and
(a-4) comprising the step of winding the hot-rolled steel sheet in the range of 400 ℃ ~ 700 ℃,
A method of manufacturing a high-strength alloyed hot-dip galvanized steel sheet.
상기 (d) 단계는,
(d-1) 상기 소둔 열처리한 냉연강판을 1℃/초 ~ 10℃/초 범위의 냉각속도로 600℃ ~ 700℃ 까지 1차 냉각하는 단계; 및
(d-2) 상기 1차 냉각한 냉연강판을 10℃/초 초과 ~ 50℃/초 미만 범위의 냉각속도로 460℃ ~ 500℃ 까지 2차 냉각하는 단계;를 포함하는,
고강도 합금화 용융아연도금 강판의 제조방법.7. The method according to claim 5 or 6,
The step (d) is,
(d-1) first cooling the cold-rolled steel sheet subjected to the annealing heat treatment to 600° C. to 700° C. at a cooling rate in the range of 1° C./sec to 10° C./sec; and
(d-2) secondary cooling of the firstly cooled cold-rolled steel sheet to 460° C. to 500° C. at a cooling rate in the range of more than 10° C./sec to less than 50° C./sec;
A method of manufacturing a high-strength alloyed hot-dip galvanized steel sheet.
상기 (d) 단계를 수행한 후에,
(e) 상기 냉연강판을 용융아연 도금욕에 침지하여 460℃ ~ 500℃의 온도에서 용융아연도금을 수행하는 단계;를 더 포함하는,
고강도 합금화 용융아연도금 강판의 제조방법.7. The method according to claim 5 or 6,
After performing step (d),
(e) immersing the cold-rolled steel sheet in a hot-dip galvanizing bath to perform hot-dip galvanizing at a temperature of 460° C. to 500° C.; further comprising
A method of manufacturing a high-strength alloyed hot-dip galvanized steel sheet.
상기 (e) 단계를 수행한 후에,
(f) 상기 용융아연 도금된 냉연강판을 490℃ ~ 530℃의 범위의 온도에서 합금화 열처리를 수행하는 단계;를 더 포함하는,
고강도 합금화 용융아연도금 강판의 제조방법.10. The method of claim 9,
After performing step (e),
(f) performing an alloying heat treatment on the hot-dip galvanized cold-rolled steel sheet at a temperature in the range of 490°C to 530°C; further comprising,
A method of manufacturing a high-strength alloyed hot-dip galvanized steel sheet.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004068050A (en) * | 2002-08-02 | 2004-03-04 | Sumitomo Metal Ind Ltd | High tensile strength cold rolled steel sheet and its manufacturing method |
| KR20090036712A (en) | 2007-10-10 | 2009-04-15 | 박윤식 | Mounting plate being able to move linearly and rotatably |
| KR20130111585A (en) * | 2010-12-17 | 2013-10-10 | 신닛테츠스미킨 카부시키카이샤 | Hot-dip zinc-plated steel sheet and process for production thereof |
| KR20130135348A (en) * | 2011-04-21 | 2013-12-10 | 신닛테츠스미킨 카부시키카이샤 | High-strength cold-rolled steel sheet with highly even stretchabilty and excellent hole expansibility, and process for producing same |
| KR20140041833A (en) * | 2011-07-29 | 2014-04-04 | 신닛테츠스미킨 카부시키카이샤 | High-strength galvanized steel sheet having superior bendability and method for producing same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004068050A (en) * | 2002-08-02 | 2004-03-04 | Sumitomo Metal Ind Ltd | High tensile strength cold rolled steel sheet and its manufacturing method |
| KR20090036712A (en) | 2007-10-10 | 2009-04-15 | 박윤식 | Mounting plate being able to move linearly and rotatably |
| KR20130111585A (en) * | 2010-12-17 | 2013-10-10 | 신닛테츠스미킨 카부시키카이샤 | Hot-dip zinc-plated steel sheet and process for production thereof |
| KR20130135348A (en) * | 2011-04-21 | 2013-12-10 | 신닛테츠스미킨 카부시키카이샤 | High-strength cold-rolled steel sheet with highly even stretchabilty and excellent hole expansibility, and process for producing same |
| KR20140041833A (en) * | 2011-07-29 | 2014-04-04 | 신닛테츠스미킨 카부시키카이샤 | High-strength galvanized steel sheet having superior bendability and method for producing same |
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