KR19980048549A - Manufacturing method of high strength structural hot dip galvanized steel sheet containing Ti and P composite - Google Patents
Manufacturing method of high strength structural hot dip galvanized steel sheet containing Ti and P composite Download PDFInfo
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- KR19980048549A KR19980048549A KR1019960067128A KR19960067128A KR19980048549A KR 19980048549 A KR19980048549 A KR 19980048549A KR 1019960067128 A KR1019960067128 A KR 1019960067128A KR 19960067128 A KR19960067128 A KR 19960067128A KR 19980048549 A KR19980048549 A KR 19980048549A
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 40
- 229910001335 Galvanized steel Inorganic materials 0.000 title claims abstract description 30
- 239000008397 galvanized steel Substances 0.000 title claims abstract description 30
- 229910052719 titanium Inorganic materials 0.000 title claims abstract description 19
- 229910052698 phosphorus Inorganic materials 0.000 title claims abstract description 17
- 239000002131 composite material Substances 0.000 title claims abstract description 6
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 60
- 239000010959 steel Substances 0.000 claims abstract description 60
- 238000000137 annealing Methods 0.000 claims abstract description 37
- 238000010438 heat treatment Methods 0.000 claims abstract description 10
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 9
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 9
- 238000005246 galvanizing Methods 0.000 claims abstract description 8
- 238000005096 rolling process Methods 0.000 claims abstract description 8
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 6
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 4
- 239000012535 impurity Substances 0.000 claims abstract description 3
- 238000000605 extraction Methods 0.000 claims abstract 2
- 229910052799 carbon Inorganic materials 0.000 claims description 10
- 238000005097 cold rolling Methods 0.000 claims description 8
- 238000005098 hot rolling Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 abstract description 30
- 238000004804 winding Methods 0.000 abstract description 7
- KDCGOANMDULRCW-UHFFFAOYSA-N 7H-purine Chemical compound N1=CNC2=NC=NC2=C1 KDCGOANMDULRCW-UHFFFAOYSA-N 0.000 abstract description 4
- 239000010936 titanium Substances 0.000 description 26
- 238000001953 recrystallisation Methods 0.000 description 12
- 230000000694 effects Effects 0.000 description 9
- 239000011572 manganese Substances 0.000 description 9
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 6
- 239000011593 sulfur Substances 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 239000006104 solid solution Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 201000006705 Congenital generalized lipodystrophy Diseases 0.000 description 4
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 4
- 239000010960 cold rolled steel Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229910000746 Structural steel Inorganic materials 0.000 description 3
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 230000009931 harmful effect Effects 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 238000007747 plating Methods 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- 238000009628 steelmaking Methods 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- 239000011701 zinc Substances 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- 238000009500 colour coating Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 229910002551 Fe-Mn Inorganic materials 0.000 description 1
- 229910001096 P 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
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- 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
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
-
- C—CHEMISTRY; METALLURGY
- 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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- C—CHEMISTRY; METALLURGY
- 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
- C23C2/26—After-treatment
-
- C—CHEMISTRY; METALLURGY
- 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
- C23C2/34—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
- C23C2/36—Elongated material
- C23C2/40—Plates; Strips
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
본 발명은 칼라 코팅 강판 및 철골조 건축 내장재(퓨린(Purine), 데크판(Deck Plate), 족장판) 용도로 주로 사용되는 인장 강도 58kg 이상의 고강도 구조용 용융 아연 도금 강판의 제조 방법에 대한 것이다.The present invention relates to a method for producing a high strength structural hot dip galvanized steel sheet with a tensile strength of 58 kg or more mainly used for color coated steel sheet and steel framed building interior materials (Purine, Deck Plate, Chieftain plate).
본 발명의 Ti, P 복합 첨가 고강도 구조용 용융 아연 도금 강판을 제조 방법은, 중량%로, C:0.001-0.005%, Mn:0.20-0.50%, Si:0.030% 이하, S:0.015% 이하, P:0.020-0.040%, Ti:0.045-0.065%, N:0.030% 이하, 잔여량의 Fe 및 기타 불가피한 불순물로 조성되어 출강되고, 유효 Ti*(Ti(%)-4C(%)-3.4 N(%)-1.5 S(%))가 -0.020~+0.020중량%가 되는 슬라브를 제강 제조하고, 이 강슬라브를 열간 사상 압연 추출 온도 900-940℃에서 열간 압연하고, 열연 권취 온도 600-640℃에서 권취한 열연 코일을 소정 범위의 냉간 압하율로 연속 냉간 압연한후, 연속소둔 용융아연도금강판 제조라인에서 580-670℃의 온도로 소둔 열처리한후, 통상의 용융 아연 도금욕을 통과시켜 아연 도금한후, 조질 압연 및 후처리를 거친후 권취하는 것을 기술 요지로 한다.The manufacturing method of the hot-dip galvanized steel sheet for high strength structural addition of Ti and P composite of this invention is C: 0.001-0.005%, Mn: 0.20-0.50%, Si: 0.030% or less, S: 0.015% or less, P by weight% : 0.020-0.040%, Ti: 0.045-0.065%, N: 0.030% or less, which is composed of remaining amount of Fe and other unavoidable impurities and pulled out, and effective Ti * (Ti (%)-4C (%)-3.4 N (%) ) -1.5 S (%)) is -0.020 to + 0.020% by weight of steel slab to produce steel slabs, hot-rolled at a hot finishing rolling extraction temperature 900-940 ℃, hot rolled winding temperature 600-640 ℃ After the cold rolled hot rolled coil is continuously cold rolled to a predetermined range of cold reduction rate, the annealing heat treatment is performed at a temperature of 580-670 ° C. in a continuous annealing hot-dip galvanized steel sheet manufacturing line, and then galvanized by passing through a hot dip galvanizing bath. After that, winding after rough rolling and post-treatment is a technical subject.
Description
본 발명은 칼라 코팅 강판 및 철골조 건축 내장재(퓨린(Purine), 데크판(Deck Plate), 족장판) 용도로 주로 사용되는 인장 강도 58kg 이상의 고강도 구조용 용융 아연 도금 강판의 제조 방법에 대한 것이다.The present invention relates to a method for producing a high strength structural hot dip galvanized steel sheet with a tensile strength of 58 kg or more mainly used for color coated steel sheet and steel framed building interior materials (Purine, Deck Plate, Chieftain plate).
연속 소둔 용융 아연 도금강판의 제조 라인(이하, CGL 이라 칭함)에서 인장 강도 58kg 이상의 고강도 구조용 용융 아연 도금 강판을 제조하는 핵심 기술은 용융 아연 도금 강판의 소재인 냉간 압연 강판의 냉간 압연 조직의 재결정되는 온도 이하에서 CGL의 소둔 열처리를 완료함으로써 냉간 압연된 소재의 압연 조직이 제공하는 고강도성과 CGL 소둔 열처리 효과가 제공하는 기동성을 동시에 갖게 하는 것이다. 즉, 회복 소둔(Recovery Annealing) 단계에서 열처리를 완료함으로써 압연 조직인 냉간 압연 강판 대비 약간의 강도 저하와 연신율 증가를 유도하여 고강도성과 가공성을 동시에 확보할 수 있는 것이다.In the production line of continuous annealing hot dip galvanized steel sheet (hereinafter referred to as CGL), a key technique for producing a high strength structural hot dip galvanized steel sheet with a tensile strength of 58 kg or more is to recrystallize the cold rolled structure of cold rolled steel sheet, which is a material of hot dip galvanized steel sheet. By completing the annealing heat treatment of CGL below the temperature, the high strength provided by the rolled structure of the cold rolled material and the mobility provided by the CGL annealing heat treatment effect are simultaneously provided. In other words, by completing the heat treatment in the recovery annealing step, it is possible to induce a slight decrease in strength and an increase in elongation compared to the cold rolled steel sheet, which is a rolled structure, thereby simultaneously securing high strength and workability.
강의 성분에 따라 재결정 온도는 약간의 차이는 있으나 통상 500-560℃ 범위이다. 따라서, 이론적으로 볼 때 CGL의 열처리 온도를 560℃ 이하로 충분히 낮출 수만 있다면 모든 강종으로 인장 강도 58kg 이상의 고강도 구조용 용융 아연 도금 강판의 제조가 가능하다. 그러나, 연속 소둔 용융 아연 도금 강판 제조 라인은 구조용강 뿐만 아니라 780-860℃로 소둔 열처리되는 저탄소강 및 고가공성 극저탄소강까지 동시에 연속적으로 생산하고 있으므로 현실적으로 표면, 형상 불량 및 설비 트러블이 없이 소둔 열처리 온도를 560℃ 이하로 낮추기는 곤란하다.Depending on the composition of the steel, the recrystallization temperature is usually in the range 500-560 ° C, with some differences. Therefore, theoretically, as long as the heat treatment temperature of CGL can be sufficiently lowered to 560 ° C. or lower, it is possible to manufacture high strength structural hot dip galvanized steel sheet having a tensile strength of 58 kg or more in all steel grades. However, the continuous annealing hot-dip galvanized steel sheet production line produces not only structural steel but also low carbon steel and high workability ultra low carbon steel which are annealed at 780-860 ° C at the same time. It is difficult to lower the temperature below 560 ° C.
따라서 연속 소둔 용융 아연 도금 강판 제조 라인에서 인장 강도 58kg 이상의 고강도 구조용 용융 아연 도금 강판을 제조시 고려해야할 최우선 전제 조건은 재결정 온도가 높은 강종을 선택해야 하는 것이다.Therefore, the first prerequisite to consider when manufacturing high strength structural hot dip galvanized steel sheet with tensile strength of 58 kg or more in the continuous annealing hot dip galvanized steel sheet manufacturing line is to select a steel grade having a high recrystallization temperature.
이와 같은 문제를 해결하기 위한 이제까지의 방법은 재결정 온도 상승 원소인 Ti를 미량 첨가하여 재결정 온도를 640-680℃로 상승시키고 현실적인 소둔열처리 가능 온도인 640-680℃ 부근에서 소둔열처리함에 따른 불가피한 재질 연질화를 보상하기 위하여 고용 강화 원소인 P를 다량 첨가하거나 C를 다량 첨가하고 있다.In order to solve such a problem, the conventional method is necessary to increase the recrystallization temperature to 640-680 ° C by adding a small amount of Ti, which is a recrystallization temperature rising element, and inevitable material softness due to annealing heat treatment near 640-680 ° C which is a realistic annealing heat treatment temperature. To compensate for the increase, a large amount of solid solution strengthening element P or C is added.
그러나, 이러한 방법은 지나친 재질 경질화에 의해 각종 표면 및 형상의 결함을 유발하고 타강종 연결 소재와의 잦은 용접부 파단에 의해 생산성이 저하하고 ASTM 규격을 초과하는 고 [P] 함유 불용성 슬라브의 발생에 의한 제강 연주 생산성의 저하 및 Ti, P의 다량 첨가에 의한 제강 제조 원가의 증가, 고도의 형상 품질이 요구되는 칼라 코팅용 박물 소재의 형상 품질의 보증의 한계에 부닥치며, 0.35mm 이하 초극박재의 생산이 불가한 등의 문제가 있는 것이다.However, this method causes defects in various surfaces and shapes by excessive hardening of the material, and the production of high [P] -insoluble slabs, which are lowered in productivity due to frequent weld breaks with other steel connection materials and exceeds ASTM standards. Reduction of steel production performance due to the reduction of steel production performance, increase of steel manufacturing cost by the addition of large amounts of Ti and P, and the limitation of the guarantee of the shape quality of the thin coating material for color coating requiring high shape quality. There is a problem such as impossible to produce.
따라서, 본 발명은 강의 성분 조성 변형 및 조업 온도 변경을 통해 연속 소둔 용융 아연도금 강판의 제조 라인의 생산성 향상, 품질 안정화(최적 재질의 안정적 확보 및 재질 편차 개선), Ti, P의 첨가량 감소 및 고[P] 불용 슬라브의 생산을 방지하여 제강 제조 원가를 절감하고 최종 수요가의 품질 요구를 만족(칼라 코팅용 박물 제조시 고도의 형상성 확보)를 동시에 충족시킬 수 있는 Ti, P 복합 첨가한 고강도 구조용 용융 아연 도금 강판의 제조 방법을 제공하는 것을 목적으로 한다.Therefore, the present invention improves the productivity of the production line of the continuous annealing hot-dip galvanized steel sheet by modifying the composition of the steel composition and changing the operating temperature, stabilizing the quality of the material (improving the stability of the material and improving the material deviation), the addition amount of Ti, P and high [P] High-strength with Ti and P complex to prevent production of insoluble slabs, reduce steel manufacturing cost and satisfy quality demands of final demand (to ensure high shape when manufacturing thin coating for thin coating) It is an object to provide a method for producing a structural hot dip galvanized steel sheet.
도 1은 본 발명에서 소둔 온도 변화에 따른 발명강과 비교강 및 종래강의 재질변화를 나타내는 그래프도이다.1 is a graph showing the material change of the invention steel and the comparative steel and the conventional steel according to the change in the annealing temperature in the present invention.
상기 목적을 달성하기 위하여 본 발명에서는 냉간 압연한 코일을 연속 소둔 용융 아연 도금 강판 제조 라인에서 연속 소둔 용융 아연 도금하여 Ti, P 복합 첨가 고강도 구조용 용융 아연 도금 강판을 제조하는 방법에 있어서, 중량%로, C:0.001-0.005%, Mn:0.30-0.50%, Si:0.030% 이하, S:0.015% 이하, P:0.020-0.040%, Ti:0.045-0.065%, N:0.030% 이하, 잔여량의 Fe 및 기타 불가피한 불순물로 조성되어 출강되고, 유효 Ti*(Ti(%)-4C(%)-3.4 N(%)-1.5 S(%))가 -0.020~+0.020%가 되는 슬라브를 열간 사상 압연 온도 900-940℃에서 열간 압연하고, 열연 권취 온도 600-640℃에서 권취한 열연 코일을 냉간 압하율 75-85%로 연속 냉간 압연한후, 연속 소둔 용융 아연 도금 강판 제조 라인에서 580-670℃로 소둔 열처리하여 용융 아연 도금조에서 아연 도금한후, 조질 압연 및 후처리를 거친후 권취하여 인장강도 58kg 이상인 고강도 구조용 용융 아연 도금 강판을 제조하는 방법을 제공한다.In order to achieve the above object, in the present invention, a cold rolled coil is continuously annealed by hot dip galvanizing in a continuous annealing hot dip galvanized steel sheet production line to produce a high strength structural hot dip galvanized steel sheet using Ti, P composite, by weight%. , C: 0.001-0.005%, Mn: 0.30-0.50%, Si: 0.030% or less, S: 0.015% or less, P: 0.020-0.040%, Ti: 0.045-0.065%, N: 0.030% or less, residual amount of Fe And hot-rolled slabs which are formed of steel and other unavoidable impurities, and have an effective Ti * (Ti (%)-4C (%)-3.4 N (%)-1.5 S (%)) of -0.020 to + 0.020%. Hot rolled at a temperature of 900-940 ° C, hot rolled coils wound at a hot rolled winding temperature of 600-640 ° C, continuously cold-rolled at a cold reduction rate of 75-85%, and then 580-670 ° C in a continuous annealing hot dip galvanized steel sheet manufacturing line. After annealing and galvanizing in a hot dip galvanizing bath, after rough rolling and post-treatment, it is wound up and pulled up to a tensile strength of 58kg or more. Provided is a method for producing a high strength structural hot dip galvanized steel sheet.
이하에서는 본 발명에 대해 상세하게 설명한다.Hereinafter, the present invention will be described in detail.
본 발명의 기술 요지는 연속 소둔 용융 아연도금강판 제조 라인에서 통상의 조업 온도인 720-860℃와 연결하여 연속 소둔이 가능한 적절한 재결정 온도를 갖는 신규 강종을 개발하고, 이 강종에 맞는 적절한 제조 기술을 공정별로 개발하여 적용함으로써 표면 및 형상 품질이 안정되고 타강종과 용접 연결하여 연속 작업시 용접 부위의 판파단과 같은 생산성 저해 요인이 없는 인장 강도 58kg 이상인 고강도 구조용 용융 아연 도금 강판을 제조하는데 있다.Summary of the Invention The technical gist of the present invention is to develop a novel steel grade having an appropriate recrystallization temperature capable of continuous annealing in connection with a typical operating temperature of 720-860 ° C in a continuous annealing hot dip galvanized steel sheet production line, By developing and applying to each process, the surface and shape quality is stabilized and welded with other steels to produce high strength structural hot-dip galvanized steel sheet with a tensile strength of 58 kg or more without continuous production factors such as plate breakage at the welding site.
이전까지 양산 적용 사용되었던 기존 강종(Ti- P 첨가 극저탄소강)이나 고강도 구조용 용융 아연 도금 강판용으로 개발되었던 기타 강종(저탄+Ti 첨가강)도 높은 재결정 온도 확보가 가능하고 고강도의 재질 확보는 가능했지만 다수의 문제점으로 연속 소둔 용융 아연 도금 강판 제조 라인에서의 양산 적용은 불가능하였다. 즉, Ti- P 첨가 극저탄소강의 경우, ASTM 규격 기준 대비 [P]가 초과되며, 재질이 지나차게 경질이고, 재질 편차가 크며, 표면 및 형상의 품질이 불안정하며, 타강종과 연결시 용접부에 판파단이 빈발하고, 고강도에 따른 냉간 압연 부하가 과중되며, 0.38mm 이하의 극박재 생산이 불가한 등의 문제가 있었다. 또한, Ti 첨가 저탄소강의 경우, 재질이 지나치게 경질이며, 폭방향의 재질 편차가 크며, 형상 품질이 열악하며(단파장 웨이브(Wave)), 타강종과 연결시 용접부에 판파단이 존재하며, 고강도에 따른 냉간 압연 부하가 과중하고, 0.4mm 이하의 극박재 생산이 불가능한 등의 문제가 있었다.Existing steel grades (Ti-P-added ultra low carbon steels) or other steel grades developed for high-strength hot-dip galvanized steel sheets, which have been used for mass production, can be secured with high recrystallization temperature and high-strength materials. However, due to a number of problems, mass production in the continuous annealing hot dip galvanized steel sheet manufacturing line was not possible. That is, in case of Ti-P-added ultra low carbon steel, [P] is exceeded compared to ASTM standard standard, the material is excessively hard, the material variation is large, the quality of surface and shape is unstable, There were problems such as frequent breakage, cold rolling load due to high strength, and the inability to produce ultrathin materials of 0.38 mm or less. In addition, in the case of Ti-added low carbon steel, the material is excessively hard, the material variation in the width direction is large, the shape quality is poor (short wave), and the plate break is present in the welded portion when connected to other steel grades. Due to the heavy cold rolling load, there was a problem such as the production of ultra-thin material of less than 0.4mm.
이하에서는 본 발명에서의 각 성분의 역할과 성분의 수치 한정 이유 및 제조 공정에서의 온도 범위 한정 등의 수치 한정 이유를 설명한다.Hereinafter, the role of each component in the present invention, the reason for numerical limitation of the component, and the reason for numerical limitation such as temperature range limitation in the manufacturing process will be described.
탄소(C)는 0.001-0.005중량%로 한정하는데, 탄소는 강판의기계적 성질에 가장 큰 영향을 미치는 원소로서 첨가량이 많을수록 강도는 증가하고 연신율은 감소한다. 본 발명에서 탄소가 상기 범위로 한정된 것은 이 범위에서 탄소가 Ti과 미세한 TiC 석출물을 가장 적절하게 형성하며, 이 TiC는 강의 재결정 온도를 크게 상승시키는 결정적 역할을 하기 때문이다. 그러나 탄소 함량이 0.005% 이상으로 과다 함유시 TiC 생성을 위해 고가의 Ti를 다량 첨가해야 하고 고탄소 함량에 따라 회복→ 소둔 과정에서의 미세 온도 변화에 다른 재질 편차가 커서 상기 종래강에서 설명한 여러 문제가 나타나기 때문이다.Carbon (C) is limited to 0.001-0.005% by weight. Carbon is the element that has the greatest influence on the mechanical properties of the steel sheet. As the amount of carbon added increases, the strength increases and the elongation decreases. In the present invention, the carbon is limited to the above range because the carbon most appropriately forms Ti and fine TiC precipitates in this range, and this TiC plays a decisive role in greatly increasing the recrystallization temperature of the steel. However, when the carbon content is more than 0.005%, a large amount of expensive Ti must be added to generate TiC, and according to the high carbon content, there are various material variations in the micro temperature change during the recovery → annealing process. Because it appears.
망간(Mn)은 0.30-0.50%로 한정하는데, 망간은 열간 취성을 일으키는 강중 S를 제거하고 약간의 재질 경화 효과를 얻기 위해 첨가되는 성분으로, 그 첨가량이 0.20 5 이하인 경우 첨가 효과가 미약하고 0.50% 이상인 경우 연성과 가공성을 떨어뜨리게 되고, 고가의 Mn을 다량 첨가하에 따라 제강 제조 원가의 상승 원인이 된다. 본 발명에서는 약간의 재질 경화 효과와 가공성 확보 측면 및 제강 제조원가를 고려하여 최적의 첨가량으로 확인된 0.20-0.50%로 첨가 범위를 제한한다.Manganese (Mn) is limited to 0.30-0.50%. Manganese is a component added to remove S in steel causing hot brittleness and to obtain a slight material hardening effect. If the amount is 0.20 or less, the addition effect is weak and 0.50. If it is more than%, the ductility and workability is reduced, and the addition of a large amount of expensive Mn causes a rise in steelmaking manufacturing cost. In the present invention, the addition range is limited to 0.20-0.50%, which has been identified as an optimum amount in consideration of a slight material hardening effect, processability, and steelmaking manufacturing cost.
인(P)은 0.020-0.040% fh 한정하는데, P는 인성 및 연성을 크게 저하시키는 원소이다. 미량 첨가시 고용 강화 효과가 가장 큰 원소로서 인장 강도 58kg 이상을 확보하고자 P를 0.020-0.040% 첨가한다. P 함량을 상기 범위로 한정한 이유는 0.040 5 이상 첨가시 불균일 조직 형성에 의해 인성 및 가공성을 크게 저하시켜 고강도 구조용강이 주로 사용되는 건축 구조물에는 사용이 적합하지 못하게 된다. 또 0.020 5 이하 소량 첨가시 고용 강화 효과 감소에 따라 얻고자하는 최소 58kg 이상의 인장 강도 확보가 불가능하다.Phosphorus (P) is limited to 0.020-0.040% fh. P is an element that greatly reduces toughness and ductility. When a small amount is added, 0.020-0.040% of P is added to secure a tensile strength of 58 kg or more as the element having the greatest solid solution strengthening effect. The reason for limiting the P content to the above range is that when added more than 0.040 5, toughness and workability are greatly reduced due to the formation of non-uniform structure, so that it is not suitable for use in building structures in which high strength structural steel is mainly used. In addition, when a small amount of 0.020 or less is added, it is impossible to secure a tensile strength of at least 58 kg, which is desired to be obtained due to the decrease in the solid solution strengthening effect.
황(S)은 0.015% 이하로 한정한다. 황은 강중에서 적열 취성을 일으키는 유해한 원소이므로 통상 Mn이나 Ti를 첨가하여 고정시킴으로써 문제점을 방지하고 있다. 따라서, 황의 양이 많을 수록 많은 양의 Mn 및 Ti이 필요하며 강에 유해한 영향을 미치므로 가능한 함량을 저하시키는 것이 바람직하다, 본 발명에서 황을 0.015 5 이하로 한정한 이유는 본 발명강에서 첨가하고자 하는 Mn 및 Ti 첨가량으로 강중 0.015 5의 황을 충분히 고정시킬 수 있기 때문이며, 황 함유량을 0.005% 이하로 할 경우 과도한 탈황 처리에 의해 제강 생산성이 저하하고 본 발명에서 제한한 Mn, Ti의 첨가량의 준수가 곤란하기 때문이다.Sulfur (S) is limited to 0.015% or less. Sulfur is a harmful element that causes red brittleness in steel, and is usually prevented by adding Mn or Ti to fix it. Therefore, the higher the amount of sulfur, the greater the amount of Mn and Ti is required and it is desirable to reduce the possible content since it has a harmful effect on the steel, the reason for limiting sulfur to 0.015 5 or less in the present invention is added in the present invention steel This is because it is possible to sufficiently fix the sulfur of 0.015 5 in the steel by the amount of Mn and Ti to be added. When the sulfur content is 0.005% or less, the steelmaking productivity decreases due to excessive desulfurization and the amount of Mn and Ti added in the present invention is limited. This is because compliance is difficult.
규소(Si)는 0.03% 이하로 한정한다. Si는 냉간 압연 코일을 도금하기 전에 소둔 열처리시 조직내 Si가 강판 표면에 용이하게 확산하여 표층 산화막을 형성하여 용융 아연과 철판과의 도금성을 저하시켜 미도금을 발생케 하는 특징이 있는 유해한 원소이다. 따라서, 본 발명에서는 Si 첨가량을 0.030% 이하로 제한한다. 제한 범위를 좀더 엄격하게 하지 못하는 이유는 Si이 강제조시 첨가하는 Fe-P, Fe-Mn 등에 따라 들어가기 때문에 엄격한 관리에 한계가 있기 때문이다.Silicon (Si) is limited to 0.03% or less. Si is a harmful element characterized by the fact that Si in the structure easily diffuses on the surface of the steel sheet during the annealing heat treatment before plating the cold rolled coil to form a surface oxide film, thereby degrading the plating property between the molten zinc and the iron plate to generate unplated. to be. Therefore, in the present invention, the Si addition amount is limited to 0.030% or less. The reason why the limit is not made more stringent is because there is a limit in strict management because Si enters Fe-P, Fe-Mn, etc. added during forcing.
질소(N)는 0.0030% 이하로 한정하는데, 질소는 침입형 고용 원소로서 과다 존재시 스트레쳐 스트레인을 일으켜 강판 표면의 품질 상태를 열화시키므로 0.0030% 이하로 제한한다.Nitrogen (N) is limited to 0.0030% or less, but nitrogen is limited to 0.0030% or less because it is an invasive solid solution element, which causes a stretcher strain to deteriorate the quality state of the steel sheet surface.
티타늄(Ti)은 0.045-0.065%로 제한하는데, Ti는 미세한 TiC 석출 입자를 형성하여 강의 재결정 온도를 상승시키고 재료의 강도를 강화시키는 원소이다. 그러나 이러한 현상은 유효 Ti 함량이 -0.0020-+0.020% 정도로 확보될 수 있게 첨가하는 것이 가장 최적으로 나타나며, 이 이상 또는 이하로 첨가시 효과가 떨어지게 된다. 따라서, 본 발명에서는 Ti는 C와 N 같은 고용 원소를 화학 양론적으로 석출시킬 수 있는 정도를 나타내는 수식인 유효 Ti*(Ti(%)-4C(%)-3.4 N(%)-1.5S(%))이 -0.020-+0.020%로 확보될 수 있는 0.045-0.065%로 한정하였다.Titanium (Ti) is limited to 0.045-0.065%. Ti is an element that forms fine TiC precipitated particles to increase the recrystallization temperature of the steel and enhance the strength of the material. However, this phenomenon is most optimally added to ensure that the effective Ti content is about -0.0020- + 0.020%, the effect is less when added above or below. Therefore, in the present invention, Ti is an effective Ti * (Ti (%)-4C (%)-3.4 N (%)-1.5S () which is a formula representing the degree of stoichiometric precipitation of solid solution elements such as C and N. %)) Is limited to 0.045-0.065%, which can be secured at -0.020- + 0.020%.
본 발명강의 재질 특성은 강의 성분에 의해서 뿐만 아니라 열연 권취 온도에 의해서도 큰 영향을 받게 된다. 열연 권취 온도가 높게 되면, 강의 탄화물(TiC), 질화물(TiN) 석출 입자가 지나치게 조대해져 미세한 석출 입자의 분산에 의해 얻고자 하는 재결정 온도 상승 효과를 얻을 수 없다. 또, 열연 권취 온도가 낮게 되면, 열연 강판이 지나치게 경하게 되어 열연 권취가 곤란하며, 후속 공정인 냉간 압연시 롤의 압연 부하가 과도하게 되어 얻고자하는 최적의 표면 및 형상 품질을 확보할 수 없다. 따라서, 본 발명에서는 열연 권취 온도를 600-640℃로 한정하였다.The material properties of the inventive steel are greatly influenced not only by the components of the steel but also by the hot rolled winding temperature. When the hot-rolled coiling temperature is high, carbide (TiC) and nitride (TiN) precipitated particles in the steel become excessively coarse, and the effect of increasing the recrystallization temperature to be obtained by dispersion of the fine precipitated particles cannot be obtained. In addition, when the hot rolled winding temperature is low, the hot rolled steel sheet becomes too hard, and thus hot rolled steel is difficult to roll, and the rolling load of the roll during the cold rolling, which is a subsequent process, becomes excessive, and the optimum surface and shape quality desired to be obtained cannot be secured. . Therefore, in this invention, the hot rolled winding temperature was limited to 600-640 degreeC.
본 발명에서 적절하게 적용될 수 있는 최적의 열연 사상 압연 온도는 900-940℃이며, 연속 냉간 압연시 냉간 압하율은 75-85%이다.Optimal hot rolling finish temperature that can be suitably applied in the present invention is 900-940 ℃, cold rolling reduction rate during continuous cold rolling is 75-85%.
다음으로 상기와 같이 냉간 압연된 냉연 강판을 연속 소둔 용융 아연 도금 강판 제조 라인의 소둔로에 투입하여 소둔 온도 580-670℃로 소둔한 다음 용융 아연 도금욕에서 아연 도금한 후 조질 압연 및 후처리후 권취함으로써 Ti, P 복합첨가 58kg 급 고강도 구조용 용융 아연 도금 강판이 제조된다. 이 소둔 온도가 580℃ 이하이면 강도는 약간 상향되지만 연신율이 저하되고 현장 조업성이 악화되어 표면 및 형상 품질의 열화를 유발하게 된다. 또, 소둔 온도가 680℃ 이상이면, 재결정 온도를 초과하게 되어 구조용급의 고강도 재질 확보가 불가능하므로 본 발명에서는 소둔 온도를 580-670℃로 한정한다.Next, the cold rolled cold rolled steel sheet as described above was introduced into an annealing furnace of a continuous annealing hot dip galvanized steel sheet production line, followed by annealing at an annealing temperature of 580-670 ° C., followed by galvanizing in a hot dip galvanizing bath, followed by temper rolling and post-treatment. By winding, a hot dip galvanized steel sheet for a high strength structural 58kg Ti and P composite additive is produced. If the annealing temperature is 580 ° C. or lower, the strength is slightly increased, but the elongation is lowered and the workability of the field is deteriorated, leading to deterioration of surface and shape quality. In addition, when the annealing temperature is 680 ° C or higher, the recrystallization temperature is exceeded, and it is impossible to secure a high-strength material for structural grades. In the present invention, the annealing temperature is limited to 580-670 ° C.
이하에서는 실시예와 관련하여 본 발명을 보다 구체적으로 설명한다.Hereinafter, the present invention will be described in more detail with reference to Examples.
[실시예 1]Example 1
본 발명강과 기존강 및 비교강의 성분 및 소둔 열처리 온도 변화에 따른 재결정 온도 변화를 실험실에서 시물레이션(Simulation)한 결과를 표 1에 나타내었다.Table 1 shows the results of simulation of the recrystallization temperature change according to the components of the inventive steel, the existing steel, and the comparative steel and the annealing heat treatment temperature.
[표 1]TABLE 1
유효 Ti* = Ti(%)-4C(%)-3.4 N(%)-1.5 S(%)로 계산되며, ASTM 규격상 C≤0.20 %, P≤0.040 % 이다.Effective Ti * = Ti (%)-4C (%)-3.4 N (%)-1.5 S (%), calculated according to ASTM standard C≤0.20%, P≤0.040%.
상기 표 1에서 알 수 있는 바와 같이, 본 발명강의 재결정 온도는 670℃로 종래강 및 비교강 대비 10℃ 정도 낮지만 회복 소둔 단계에서의 소둔 가능 온도범위는 90℃로 넓어서 종래강 및 비교강 대비 월등 우수함을 알 수 있다. 또한, 도 1에는 발명강과 비교강 및 종래강을 비교하여 소둔 온도 변화에 따른 재질 거동을 나타내고 있는데, 본 발명강이 종래강 및 비교강에 비해 안정적임을 알 수 있다.As can be seen in Table 1, the recrystallization temperature of the present invention steel is about 670 ℃ 10 ℃ lower than conventional steel and comparative steel, but the temperature range available for annealing in the recovery annealing step is 90 ℃ wide compared to conventional steel and comparative steel It can be seen that the superiority. In addition, Figure 1 shows the material behavior according to the annealing temperature change by comparing the inventive steel, the comparative steel and the conventional steel, it can be seen that the inventive steel is more stable than the conventional steel and comparative steel.
[실시예 2]Example 2
상기 표 1에 나타난 성분 조성의 슬라브를 920℃에서 열간 사상 압연하고 619℃에서 열연 권취한 후 연속 냉간 압연하여 냉연 강판을 제조하였고, 이 냉연강판을 연소속 둔용 아연도금강판 제조 라인에서 580-670℃로 연속 소둔한후 용융 아연욕에서 아연 도금한후 조질 압연 및 후처리후 기계적 성질을 분석하여 그 결과를 표 2에 나타내었다.The slab of the composition shown in Table 1 was hot rolled at 920 ° C., hot rolled at 619 ° C., and then continuously cold rolled to produce a cold rolled steel sheet. After continuous annealing at ℃ and zinc plating in a molten zinc bath, the mechanical properties after the rough rolling and post-treatment were analyzed and the results are shown in Table 2.
표 2로부터 알 수 있는 바와 같이, 종래강은 기계적 성질은 양호하나 P 성분이 ASTM 규격 기준인 0.040% 이하를 만족하지 못하고 초과함을 알 수 있으며, 비교강은 과도하게 경질인등 결점을 다수 가지나, 본 발명강은 표면 품질 및 형상 품질이 우수하고, 용접성 및 통판성이 우수하며, 재질 강도도 최적성을 나타내며, 냉간 압연성이 매우 우수함을 알 수 있다.As can be seen from Table 2, the conventional steel has good mechanical properties, but it can be seen that the P component does not meet or exceed 0.040%, which is an ASTM standard, but the comparative steel has many defects such as being excessively hard. The steel of the present invention is excellent in surface quality and shape quality, excellent weldability and sheeting, excellent material strength, and excellent cold rolling property.
[표 2]TABLE 2
상기 설명한 바와 같이, 본 발명의 Ti, P 복합 첨가 고강도 구조용 용융 아연 도금 강판의 제조 방법에 의하면, 본 발명강의 표면 품질 및 형상 품질이 우수하고, 용접성 및 통판성이 우수하며, 재질 강도도 최적성을 나타내며, 냉간 압연성이 매우 우수하여 구조용 강재에서 요구되는 물성을 양호하게 구비하여, 연속 소둔 용융아연도금강판 제조 라인의 생산성을 향상시키고, 최적 재질의 안정적 확보 및 재질 편차를 개선하여 품질의 안정화를 도모할 수 있으며, Ti, P 합금철 첨가량를 감소시키며, 고[P] 불용 슬라브의 생산을 방지할 수 있어서 제강 제조 원가를 절감하며, 칼라 코팅용 박물 제조시 고도의 형상성을 확보할 수 있어서 최종 수요가의 품질을 만족시킬 수 있는 등 유용한 효과가 달성되는 것이다.As described above, according to the manufacturing method of the hot-dip galvanized steel sheet for high strength structural addition of Ti and P composite of the present invention, the surface quality and the shape quality of the steel of the present invention are excellent, weldability and sheeting property, and material strength are also optimal. It has excellent cold rolling property, and has good physical properties required for structural steel, which improves the productivity of continuous annealing hot-dip galvanized steel sheet manufacturing line, stabilizes quality and improves material variation, thereby stabilizing quality. It can reduce the amount of Ti, P alloy iron addition, prevent the production of high [P] insoluble slabs, reduce the steel manufacturing cost, and ensure the high shape when manufacturing the color coating thin material Useful effects can be achieved, such as satisfying the final demand price.
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