WO2013018739A1 - 曲げ性に優れた高強度亜鉛めっき鋼板およびその製造方法 - Google Patents
曲げ性に優れた高強度亜鉛めっき鋼板およびその製造方法 Download PDFInfo
- Publication number
- WO2013018739A1 WO2013018739A1 PCT/JP2012/069260 JP2012069260W WO2013018739A1 WO 2013018739 A1 WO2013018739 A1 WO 2013018739A1 JP 2012069260 W JP2012069260 W JP 2012069260W WO 2013018739 A1 WO2013018739 A1 WO 2013018739A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- steel sheet
- hardness
- less
- strength
- base steel
- Prior art date
Links
- 229910001335 Galvanized steel Inorganic materials 0.000 title claims abstract description 85
- 239000008397 galvanized steel Substances 0.000 title claims abstract description 85
- 238000004519 manufacturing process Methods 0.000 title claims description 22
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 280
- 239000010959 steel Substances 0.000 claims abstract description 280
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 118
- 239000002344 surface layer Substances 0.000 claims abstract description 67
- 239000010410 layer Substances 0.000 claims abstract description 59
- 229910052742 iron Inorganic materials 0.000 claims abstract description 55
- 229910001566 austenite Inorganic materials 0.000 claims abstract description 45
- 238000009826 distribution Methods 0.000 claims abstract description 34
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 17
- 239000012535 impurity Substances 0.000 claims abstract description 16
- 238000005246 galvanizing Methods 0.000 claims abstract description 9
- 229910000859 α-Fe Inorganic materials 0.000 claims description 62
- 238000000034 method Methods 0.000 claims description 61
- 238000000137 annealing Methods 0.000 claims description 47
- 230000009466 transformation Effects 0.000 claims description 43
- 229910000734 martensite Inorganic materials 0.000 claims description 41
- 230000000717 retained effect Effects 0.000 claims description 35
- 238000005096 rolling process Methods 0.000 claims description 33
- 238000005098 hot rolling Methods 0.000 claims description 31
- 238000005275 alloying Methods 0.000 claims description 29
- 238000001816 cooling Methods 0.000 claims description 25
- 229910001563 bainite Inorganic materials 0.000 claims description 22
- 238000005097 cold rolling Methods 0.000 claims description 21
- 238000010438 heat treatment Methods 0.000 claims description 20
- 238000005259 measurement Methods 0.000 claims description 19
- 238000007747 plating Methods 0.000 claims description 17
- 238000007542 hardness measurement Methods 0.000 claims description 15
- 229910052739 hydrogen Inorganic materials 0.000 claims description 15
- 239000001257 hydrogen Substances 0.000 claims description 15
- 230000036961 partial effect Effects 0.000 claims description 15
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 14
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 12
- 229910052684 Cerium Inorganic materials 0.000 claims description 10
- 229910052791 calcium Inorganic materials 0.000 claims description 9
- 229910052749 magnesium Inorganic materials 0.000 claims description 9
- 229910001562 pearlite Inorganic materials 0.000 claims description 9
- 229910052735 hafnium Inorganic materials 0.000 claims description 7
- 229910052726 zirconium Inorganic materials 0.000 claims description 7
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 6
- 239000002131 composite material Substances 0.000 claims description 6
- 239000011574 phosphorus Substances 0.000 claims description 6
- 229910001392 phosphorus oxide Inorganic materials 0.000 claims description 6
- VSAISIQCTGDGPU-UHFFFAOYSA-N tetraphosphorus hexaoxide Chemical compound O1P(O2)OP3OP1OP2O3 VSAISIQCTGDGPU-UHFFFAOYSA-N 0.000 claims description 6
- 229910045601 alloy Inorganic materials 0.000 claims description 5
- 239000000956 alloy Substances 0.000 claims description 5
- 230000001174 ascending effect Effects 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 abstract description 20
- 239000000463 material Substances 0.000 abstract description 17
- 229910052710 silicon Inorganic materials 0.000 abstract description 14
- 229910052748 manganese Inorganic materials 0.000 abstract description 13
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 12
- 229910052717 sulfur Inorganic materials 0.000 abstract description 11
- 229910052782 aluminium Inorganic materials 0.000 abstract description 9
- 238000005452 bending Methods 0.000 description 42
- 230000000694 effects Effects 0.000 description 34
- 230000001965 increasing effect Effects 0.000 description 24
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 14
- 238000005261 decarburization Methods 0.000 description 13
- 230000001771 impaired effect Effects 0.000 description 11
- 150000001247 metal acetylides Chemical class 0.000 description 11
- 238000005728 strengthening Methods 0.000 description 11
- 239000010960 cold rolled steel Substances 0.000 description 10
- 229910052751 metal Inorganic materials 0.000 description 10
- 239000002184 metal Substances 0.000 description 10
- 239000000203 mixture Substances 0.000 description 10
- 239000000126 substance Substances 0.000 description 10
- 238000012360 testing method Methods 0.000 description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 239000013078 crystal Substances 0.000 description 8
- 239000002245 particle Substances 0.000 description 7
- 230000001186 cumulative effect Effects 0.000 description 6
- 238000005554 pickling Methods 0.000 description 6
- 229910052719 titanium Inorganic materials 0.000 description 6
- 229910052804 chromium Inorganic materials 0.000 description 5
- 239000002244 precipitate Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 229910001567 cementite Inorganic materials 0.000 description 4
- 229910052802 copper Inorganic materials 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 238000007373 indentation Methods 0.000 description 4
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 4
- 229910052759 nickel Inorganic materials 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 230000002829 reductive effect Effects 0.000 description 4
- 238000005266 casting Methods 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 229910052747 lanthanoid Inorganic materials 0.000 description 3
- 150000002602 lanthanoids Chemical class 0.000 description 3
- 229910052746 lanthanum Inorganic materials 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 238000001953 recrystallisation Methods 0.000 description 3
- 229910052718 tin Inorganic materials 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- 239000011701 zinc Substances 0.000 description 3
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 229910052787 antimony Inorganic materials 0.000 description 2
- 229910052790 beryllium Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910052797 bismuth Inorganic materials 0.000 description 2
- 229910052792 caesium Inorganic materials 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 229910052740 iodine Inorganic materials 0.000 description 2
- 229910052745 lead Inorganic materials 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 229910052758 niobium Inorganic materials 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 229910052712 strontium Inorganic materials 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- 210000001519 tissue Anatomy 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 229910001122 Mischmetal Inorganic materials 0.000 description 1
- 229910001035 Soft ferrite Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 229910001297 Zn alloy Inorganic materials 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- -1 and by volume% Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 235000019362 perlite Nutrition 0.000 description 1
- 239000010451 perlite Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000003303 reheating Methods 0.000 description 1
- XGVXKJKTISMIOW-ZDUSSCGKSA-N simurosertib Chemical compound N1N=CC(C=2SC=3C(=O)NC(=NC=3C=2)[C@H]2N3CCC(CC3)C2)=C1C XGVXKJKTISMIOW-ZDUSSCGKSA-N 0.000 description 1
- 210000004872 soft tissue Anatomy 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 238000011179 visual inspection Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- 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
- C23C2/28—Thermal after-treatment, e.g. treatment in oil bath
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
- B32B15/013—Layered products comprising a layer of metal all layers being exclusively metallic one layer being formed of an iron alloy or steel, another layer being formed of a metal other than iron or aluminium
-
- 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
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
-
- 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
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
-
- 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
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0273—Final recrystallisation annealing
-
- 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
- C21D8/041—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 involving a particular fabrication or treatment of ingot or slab
-
- 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
- C21D8/0436—Cold rolling
-
- 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
- C21D8/0447—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
- C21D8/0473—Final recrystallisation annealing
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
- C21D9/48—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals deep-drawing sheets
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
-
- C—CHEMISTRY; METALLURGY
- 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
-
- 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
- C23C2/0224—Two or more thermal pretreatments
-
- 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
- C23C2/024—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by cleaning or etching
-
- 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
-
- 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
- C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/001—Austenite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C18/00—Alloys based on zinc
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
- Y10T428/12611—Oxide-containing component
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12771—Transition metal-base component
- Y10T428/12785—Group IIB metal-base component
- Y10T428/12792—Zn-base component
- Y10T428/12799—Next to Fe-base component [e.g., galvanized]
Definitions
- the present invention relates to a high-strength galvanized steel sheet and a method for producing the same, and particularly to a high-strength galvanized steel sheet having excellent bendability and a method for producing the same.
- Patent Document 1 discloses that the chemical composition of the steel sheet is C: more than 0.02% and 0.20% or less, and Si: 0.01-2.0% in mass%. , Mn: 0.1-3.0%, P: 0.003-0.10%, S: 0.020% or less, Al: 0.001-1.0%, N: 0.0004-0.
- the steel sheet containing ferrite in an area ratio of 30 to 95%, and the remaining second phase It consists of one or more of martensite, bainite, pearlite, cementite and retained austenite, and when martensite is contained, the martensite area ratio is 0 to 50%, and the steel sheet has a grain size of 2 Average grain size of Ti-based carbonitride precipitates of ⁇ 30nm Contained between distance 30 ⁇ 300 nm, and high-tensile galvanized steel sheet has been proposed which contains a particle diameter 3 ⁇ m or more crystallization-based TiN at a distance 50 ⁇ 500 [mu] m average interparticle.
- Patent Document 2 as a hot dip galvanized steel sheet having excellent bendability, C: 0.03-0.11%, Si: 0.005-0.5%, Mn: 2.0- 4.0%, P: 0.1% or less, S: 0.01% or less, sol. Al: 0.01 to 1.0%, N: 0.01% or less, and Ti: N0: 0.50% or less and Nb: 0.50% or less, Ti + Nb / 2 ⁇ 0.03 (Ti and Nb in the formula indicate the content (unit: mass%) of each element), with the remainder having a chemical composition composed of Fe and impurities,
- the average interval in the plate width direction of the Mn-concentrated portion expanded in the rolling direction at the 20t depth position (t: plate thickness of the steel plate) is 300 ⁇ m or less, the area ratio of ferrite is 60% or more, and the average of ferrite
- the particle size is 1.0 to 6.0 ⁇ m, and the particle size is 1 to 10 nm in the ferrite.
- Patent Document 3 as a hot-dip galvanized steel sheet having both ductility and bendability, C: 0.08 to 0.25%, Si: 0.7% or less, Mn: 1.0 to 2.6%, Al: 1.5% or less, P: 0.03% or less, S: 0.02% or less and N: 0.01% or less, and the relationship between Si and Al is 1 0.0% ⁇ Si + Al ⁇ 1.8%, having a chemical composition consisting of the balance Fe and impurities, TS ⁇ 590 (TS: tensile strength (MPa)), TS ⁇ El ⁇ 17500 (El: total elongation ( %)), And ⁇ ⁇ 1.5 ⁇ t ( ⁇ : critical bending radius (mm), t: plate thickness (mm)), a cold-rolled steel sheet having a plated layer containing zinc on the surface thereof Is described.
- TS ⁇ 590 TS: tensile strength (MPa)
- TS ⁇ El ⁇ 17500 (El: total elongation ( %)
- Patent Document 4 as a cold-rolled steel sheet having good ductility and bendability, C: 0.08 to 0.20%, Si: 1.0% or less, Mn: 1.8 to 3.0%, P: 0.1% or less, S: 0.01% or less, sol. Al: 0.005 to 0.5%, N: 0.01% or less and Ti: 0.02 to 0.2%, with a chemical composition consisting of Fe and impurities, and by volume%, ferrite : 10% or more, bainite: 20 to 70%, residual austenite: 3 to 20% and martensite: 0 to 20%, the ferrite has an average particle size of 10 ⁇ m or less, and the bainite has an average particle size of 10 ⁇ m or less.
- TS tensile strength
- TS tensile strength
- El total elongation
- Product (TS ⁇ El value) is 14000 MPa ⁇ % or more, and the minimum bending radius in the bending test is 1.5 t or less (t: plate thickness), and the plate thickness is 2.0.
- Patent Document 5 as an alloyed hot-dip galvanized steel sheet having excellent bendability, C: 0.03-0.12%, Si: 0.02-0.50%, Mn: 2.0- 4.0%, P: 0.1% or less, S: 0.01% or less, sol. Al: 0.01 to 1.0% and N: 0.01% or less, and Ti: N0: 0.50% or less and Nb: 0.50% or less, Ti + Nb / 2 ⁇ 0.03 is contained, the balance has a chemical composition consisting of Fe and impurities, the area ratio of ferrite is 60% or more, and the average grain size of ferrite is 1.0 to 6.0 ⁇ m.
- the alloyed hot-dip galvanized layer having a steel structure contains Fe: 8 to 15% and Al: 0.08 to 0.50% by mass, and the balance is made of Zn and impurities.
- the hot-dip galvanized steel sheet has a tensile strength of 540 MPa or more, and an alloyed hot-dip galvanized steel sheet having excellent bendability is described.
- Patent Document 6 as a high-strength hot-dip galvanized steel sheet excellent in workability, C: 0.03 to 0.17%, Si: 0.01 to 0.75%, Mn: 1.5 ⁇ 2.5%, P: 0.080% or less, S: 0.010% or less, sol. Al: 0.01 to 1.20%, Cr: 0.3 to 1.3%, with the balance being Fe and inevitable impurities, steel structure is 30 to 70% ferrite by volume, 3% There is a description of a steel sheet having a hot dip galvanized layer on a base steel sheet that is composed of less retained austenite and the remaining martensite, and 20% or more of the martensite is tempered martensite.
- Patent Document 7 as an ultra-high strength cold-rolled steel sheet having excellent bending workability, wt%, C: 0.12 to 0.30%, Si: 1.2% or less, Mn: 1 to 3%, P: 0.020% or less, S: 0.010% or less, sol.
- the balance is a composite structure of residual austenite with a content of less than 10 vol% and a low-temperature transformation phase or further ferrite.
- the present invention provides a high-strength galvanized steel sheet having excellent bendability and a method for producing the same.
- the present inventors can prevent all of cracks inside the steel sheet, which is a base material generated in the deformed portion by bending, necking at the interface between the steel sheet surface and the plating layer, and destruction / peeling of the plating layer.
- intensive investigations were repeated.
- the present inventors have a predetermined chemical component, and in the base steel sheet structure, the retained austenite is limited to 8% or less in volume fraction, and the kurtosis K * of the hardness distribution described later is ⁇ 0.
- such a high-strength galvanized steel sheet has a maximum tensile strength of 900 MPa or more, but the Vickers hardness of the surface layer of the base steel sheet is lower than that of the 1/4 thickness Vickers hardness, and bending is performed.
- the surface layer of the base steel plate is easily deformed, and in the base steel plate structure, the retained austenite that is the starting point of fracture is limited to 8% or less in volume fraction. Cracks are not easily generated inside.
- such a high-strength galvanized steel sheet has a hardness distribution with a kurtosis K * of ⁇ 0.30 or less and a small variation in hardness distribution in the base steel sheet. There are few boundaries where large areas contact each other, and cracks are unlikely to occur inside the base steel sheet when bending is performed. Further, such a high-strength galvanized steel sheet has a lower Vickers hardness of the surface layer of the base material steel plate than the Vickers hardness of 1/4 thickness, and is excellent in the ductility of the surface layer of the base material steel plate. Necking at the interface between the surface of the base material steel plate and the alloyed galvanized layer is prevented at the interface between the surface of the base material steel plate and the alloyed galvanized layer when bending is performed. Is unlikely to occur.
- Such a high-strength galvanized steel sheet has an iron content of 8 to 12% in the alloyed galvanized layer, and has excellent adhesion at the interface between the surface of the base steel sheet and the galvanized layer. Therefore, when bending is performed, the alloyed galvanized layer is not easily broken or peeled off.
- the present invention has been completed on the basis of such knowledge, and the gist thereof is as follows.
- the hardness of the second largest measured value is 2% hardness, and when the total number of hardness measured values is multiplied by 0.98 and the number includes a decimal number, an integer N0.98 obtained by rounding it down is obtained.
- the hardness of the N0.98th largest measured value from the measured value of the minimum hardness is 98% hardness
- the kurtosis K * of the hardness distribution between the 2% hardness and the 98% hardness is ⁇ 0. .30 or less
- the ratio of the Vickers hardness of the surface layer of the base steel plate to the quarter thickness of the Vickers hardness of the base steel plate is 0.35 to 0.70. High strength with excellent bendability with iron content of 8-12% by mass Galvanized steel sheet.
- the volume fraction of ferrite is 10 to 75% and the total is 10 to 50% bainitic ferrite.
- the base steel plate is further mass%, B: 0.0001 to 0.0100%, Cr: 0.01 to 2.00%, Ni: 0.01 to 2.00%, Cu: 0.01 to High strength with excellent bendability according to (1), containing one or more of 2.00%, Mo: 0.01 to 1.00%, W: 0.01 to 1.00% Galvanized steel sheet.
- the base steel sheet further contains one or more of Ca, Ce, Mg, Zr, Hf, and REM in a total amount of 0.0001 to 0.5000% by mass, and has excellent bendability according to (1).
- High strength galvanized steel sheet is one or more of Ca, Ce, Mg, Zr, Hf, and REM in a total amount of 0.0001 to 0.5000% by mass, and has excellent bendability according to (1).
- One or both of a film made of phosphorus oxide and a film made of composite oxide containing phosphorus are formed on the surface of the alloyed galvanized layer, and the bendability is excellent in (1) Strength galvanized steel sheet.
- a continuous annealing process that cools at an average cooling rate of 5.0 ° C./second and cools a temperature range of 650 ° C. to 500 ° C. at an average cooling rate of 5 to 200 ° C./second, and galvanizes the steel sheet after the continuous annealing step
- a plating alloying step in which an alloying treatment is performed in which the alloy is retained for 10 to 120 seconds at a temperature of 470 to 650 ° C. after being immersed in a bath, and a method for producing a high-strength galvanized steel sheet having excellent bendability.
- the high-strength galvanized steel sheet of the present invention is, in mass%, C: 0.075 to 0.300%, Si: 0.30 to 2.50%, Mn: 1.30 to 3.50%, P: 0. 0.001 to 0.050%, S: 0.0001 to 0.0100%, Al: 0.005 to 1.500%, N: 0 to 0.0100%, O: 0 to 0.0100%
- the balance is a high-strength galvanized steel sheet having a tensile strength of 900 MPa or more in which an alloyed galvanized layer is formed on the surface of a base steel sheet made of iron and inevitable impurities.
- C: 0.075-0.300% C is contained in order to increase the strength of the base steel sheet.
- the C content is preferably 0.250% or less, and more preferably 0.220% or less.
- the C content is less than 0.075%, the strength is lowered, and the maximum tensile strength of 900 MPa or more cannot be ensured.
- the C content is preferably 0.090% or more, and more preferably 0.100% or more.
- Si: 0.30-2.50% Si is an element necessary for suppressing the formation of iron-based carbides in the base steel sheet and enhancing the strength and formability. Further, as a solid solution strengthening element, it is an element that improves stretch flangeability in order to increase the hardness of the surface layer of the base steel plate. However, if the Si content exceeds 2.50%, the base steel sheet becomes brittle and the ductility deteriorates. From the viewpoint of ductility, the Si content is preferably 2.20% or less, and more preferably 2.00% or less. On the other hand, when the Si content is less than 0.30%, a large amount of coarse iron-based carbide is generated during the alloying treatment of the alloyed galvanized layer, and the strength and formability deteriorate. In this respect, the lower limit value of Si is preferably 0.50% or more, and more preferably 0.70% or more.
- Mn: 1.30 to 3.50% Mn is contained to increase the strength of the base steel sheet.
- Mn content exceeds 3.50%, a coarse Mn-concentrated portion is generated at the center of the thickness of the base steel sheet, and brittleness is likely to occur, and troubles such as cracking of the cast slab are likely to occur.
- the Mn content needs to be 3.50% or less.
- the Mn content is preferably 3.20% or less, and more preferably 3.00% or less.
- the Mn content needs to be 1.30% or more.
- the Mn content is preferably 1.50% or more, and more preferably 1.70% or more.
- P 0.001 to 0.050%
- P tends to segregate in the central part of the thickness of the base steel sheet, and causes the weld to become brittle.
- the P content exceeds 0.050%, the welded portion is significantly embrittled, so the P content is limited to 0.050% or less.
- the lower limit of the content of P is not particularly defined, the effect of the present invention is exhibited. However, since the content of P is less than 0.001% is accompanied by a significant increase in production cost, 0.001 % Is the lower limit.
- S 0.0001 to 0.0100% S adversely affects weldability and manufacturability during casting and hot rolling. Therefore, the upper limit value of the S content is set to 0.0100% or less. Further, since S is combined with Mn to form coarse MnS to lower the ductility and stretch flangeability, it is preferably 0.0050% or less, and more preferably 0.0025% or less. The lower limit of the content of S is not particularly defined, and the effect of the present invention is exhibited. However, if the content of S is less than 0.0001%, a significant increase in production cost is caused, so 0.0001% Is the lower limit.
- Al: 0.005-1.500% suppresses the formation of iron-based carbides and increases the strength and formability of the base steel sheet. However, if the Al content exceeds 1.500%, weldability deteriorates, so the upper limit of the Al content is set to 1.500%. From this viewpoint, the Al content is preferably 1.200% or less, and more preferably 0.900% or less. Al is also an effective element as a deoxidizing material, but if the Al content is less than 0.005%, the effect as a deoxidizing material cannot be obtained sufficiently, so the lower limit of the Al content is 0. 0.005% or more. In order to obtain a sufficient deoxidation effect, the Al content is preferably 0.010% or more.
- N 0.0001 to 0.0100% N forms coarse nitrides and degrades ductility and stretch flangeability, so it is necessary to suppress the addition amount.
- N content exceeds 0.0100%, this tendency becomes remarkable, so the N content range is set to 0.0100% or less. Further, N is better because it causes blowholes during welding.
- the lower limit of the content of N is not particularly defined, and the effect of the present invention is exhibited. However, if the content of N is less than 0.0001%, a significant increase in manufacturing cost is caused, so 0.0001% Is the lower limit.
- O forms an oxide and deteriorates ductility and stretch flangeability, so the content needs to be suppressed.
- the upper limit of the O content is set to 0.0100% or less.
- the O content is preferably 0.0080% or less, and more preferably 0.0060% or less.
- the lower limit of the content of O is not particularly defined, the effects of the present invention are exhibited. However, if the content of O is less than 0.0001%, a significant increase in manufacturing cost is caused, so 0.0001% Was the lower limit.
- the base steel plate constituting the high-strength galvanized steel plate of the present invention may further contain the following elements as necessary.
- Ti: 0.005 to 0.150%” Ti is an element that contributes to increasing the strength of the base steel sheet by strengthening precipitates, strengthening fine grains by suppressing the growth of ferrite crystal grains, and strengthening dislocations by suppressing recrystallization.
- the Ti content is preferably 0.150% or less.
- the Ti content is more preferably 0.100% or less, and further preferably 0.070% or less.
- the lower limit of the Ti content is not particularly defined, and the effects of the present invention are exhibited.
- the Ti content is preferably 0.005% or more.
- the Ti content is more preferably 0.010% or more, and further preferably 0.015% or more.
- Nb 0.005 to 0.150%
- Nb is an element that contributes to an increase in the strength of the base steel sheet by strengthening precipitates, strengthening fine grains by suppressing the growth of ferrite crystal grains, and strengthening dislocations by suppressing recrystallization.
- the Nb content is preferably 0.150% or less.
- the Nb content is more preferably 0.100% or less, and further preferably 0.060% or less.
- the lower limit of the Nb content is not particularly defined, and the effects of the present invention are exhibited.
- the Nb content is preferably 0.005% or more.
- the Nb content is more preferably 0.010% or more, and further preferably 0.015% or more.
- B 0.0001 to 0.0100%
- B is an element that suppresses phase transformation at high temperatures and is effective for increasing the strength, and may be added instead of a part of C and / or Mn.
- the B content is preferably 0.0100% or less.
- the B content is more preferably 0.0050% or less, and further preferably 0.0030% or less.
- the lower limit of the content of B is not particularly defined, and the effect of the present invention is exhibited.
- the content of B should be 0.0001% or more. preferable.
- the B content is more preferably 0.0003% or more, and more preferably 0.0005% or more.
- Cr: 0.01-2.00% Cr is an element that suppresses phase transformation at high temperature and is effective for increasing the strength, and may be added instead of a part of C and / or Mn. If the Cr content exceeds 2.00%, hot workability is impaired and productivity is lowered. Therefore, the Cr content is preferably 2.00% or less. Although the lower limit of the Cr content is not particularly defined, the effect of the present invention is exhibited. However, in order to sufficiently obtain the effect of increasing the strength by Cr, the Cr content may be 0.01% or more. preferable.
- Ni 0.01-2.00%
- Ni is an element that suppresses phase transformation at high temperature and is effective for increasing the strength, and may be added instead of a part of C and / or Mn. If the Ni content exceeds 2.00%, weldability is impaired, so the Ni content is preferably 2.00% or less.
- the lower limit of the Ni content is not particularly defined, and the effects of the present invention are exhibited. However, in order to sufficiently obtain the effect of increasing the strength by Ni, the Ni content should be 0.01% or more. preferable.
- Cu: 0.01-2.00% is an element that increases the strength by being present in the steel as fine particles, and can be added instead of a part of C and / or Mn. If the Cu content exceeds 2.00%, weldability is impaired, so the Cu content is preferably 2.00% or less. The lower limit of the Cu content is not particularly defined, and the effect of the present invention is exhibited. However, in order to sufficiently obtain the effect of increasing the strength by Cu, the Cu content should be 0.01% or more. preferable.
- Mo 0.01-1.00%
- Mo is an element that suppresses phase transformation at high temperatures and is effective for increasing the strength, and may be added instead of a part of C and / or Mn. If the Mo content exceeds 1.00%, hot workability is impaired and productivity is lowered. For this reason, the Mo content is preferably 1.00% or less.
- the lower limit of the content of Mo is not particularly defined, and the effect of the present invention is exhibited. However, in order to sufficiently obtain the effect of increasing the strength by Mo, the content of Mo is 0.01% or more. preferable.
- W 0.01-1.00%
- W is an element that suppresses phase transformation at high temperatures and is effective for increasing the strength, and may be added instead of a part of C and / or Mn. If the W content exceeds 1.00%, hot workability is impaired and productivity is lowered. Therefore, the W content is preferably 1.00% or less.
- the lower limit of the W content is not particularly defined, and the effects of the present invention are exhibited. However, in order to sufficiently obtain the effect of increasing the strength by W, the W content may be 0.01% or more. preferable.
- V 0.005-0.150%
- V is an element that contributes to increasing the strength of the base steel sheet by strengthening precipitates, strengthening fine grains by suppressing the growth of ferrite crystal grains, and dislocation strengthening by suppressing recrystallization.
- the V content is preferably 0.150% or less.
- the lower limit of the content of V is not particularly limited, and the effect of the present invention is exhibited.
- the content of V is preferably 0.005% or more.
- Ca, Ce, Mg, Zr, Hf, and REM are effective elements for improving formability, and one or more of them can be added.
- the total content of one or more of Ca, Ce, Mg, Zr, Hf, and REM exceeds 0.5000%, the ductility may be impaired. For this reason, the total content of each element is preferably 0.5000% or less.
- the lower limit of the content of one or more of Ca, Ce, Mg, Zr, Hf, and REM is not particularly defined and the effect of the present invention is exhibited, but the effect of improving the formability of the base steel sheet
- the total content of the elements is preferably 0.0001% or more.
- the total content of one or more of Ca, Ce, Mg, Zr, Hf, and REM is more preferably 0.0005% or more, and 0.0010% or more. Is more preferable.
- REM is an abbreviation for Rare Earth Metal and refers to an element belonging to the lanthanoid series.
- REM and Ce are often added by misch metal and may contain a lanthanoid series element in combination with La and Ce. Even if these lanthanoid series elements other than La and Ce are included as inevitable impurities, the effect of the present invention is exhibited. Even if the metal La or Ce is added, the effect of the present invention is exhibited.
- the volume fraction of retained austenite is preferably 5% or less.
- the metal structure in the range of 1/8 thickness to 3/8 thickness centering on 1/4 of the thickness of the base steel sheet represents the overall structure of the base steel sheet. Accordingly, if the retained austenite is limited to 8% or less in volume fraction in the range of 1/8 to 3/8 thickness of the base steel sheet, the residual austenite is substantially reduced in the entire structure of the base steel sheet. Can be considered to be limited to 8% or less in volume fraction. For this reason, in the present invention, the retained austenite in the range of 1/8 to 3/8 thickness of the base steel sheet defines the range of volume fraction.
- the structure of the base steel sheet of the high-strength galvanized steel sheet according to the present invention is that the above-mentioned retained austenite is limited to 8% or less in volume fraction, and 1 / centered on 1/4 of the plate thickness. In the range of 8 to 3/8 thickness, 10 to 75% ferrite in volume fraction, 10 to 50% bainitic ferrite and / or bainite in total, and 10 to 50% tempering It preferably contains martensite. Moreover, it is preferable that fresh martensite is limited to 15% or less in volume fraction and pearlite is limited to 5% or less in volume fraction.
- the kurtosis K * of the hardness distribution to be described later is ⁇ 0.30 or less, and it has better bendability. It becomes a high-strength galvanized steel sheet.
- the metal structure such as ferrite is in a predetermined range in the entire structure of the base steel plate.
- the metal structure in the range of 1/8 thickness to 3/8 thickness centering on 1/4 of the thickness of the base steel sheet represents the overall structure of the base steel sheet.
- the volume fraction of ferrite is 10 to 75%, and the total is 10 to 50% bainitic ferrite and / or bainite.
- 10 to 50% tempered martensite fresh martensite is limited to 15% or less in volume fraction
- pearlite is limited to 5% or less in volume fraction.
- the metal structure such as ferrite is within a predetermined range in the entire structure of the steel sheet.
- the range of the volume fraction of the metal structure such as ferrite is defined in the range of 1/8 to 3/8 thickness of the base steel plate.
- Ferrite is a structure effective for improving ductility, and is preferably contained in the structure of the base steel sheet in a volume fraction of 10 to 75%. When the volume fraction of ferrite is less than 10%, sufficient ductility may not be obtained.
- the volume fraction of ferrite contained in the structure of the base steel sheet is more preferably 15% or more, and further preferably 20% or more, from the viewpoint of ductility. Further, since ferrite is a soft structure, if the volume fraction exceeds 75%, sufficient strength may not be obtained.
- the volume fraction of ferrite contained in the base steel plate structure is preferably 65% or less, and more preferably 50% or less.
- Perlite 5% or less
- the volume fraction of pearlite contained in the structure of the base steel sheet is limited to 5% or less. More preferably, it is 2% or less.
- Total 10-50% bainitic ferrite and / or bainite Bainitic ferrite and bainite have a structure with an excellent balance between strength and ductility, and the structure of the base steel sheet contains 10 to 50% total bainitic ferrite and bainite in volume fraction.
- Bainitic ferrite and bainite are microstructures having an intermediate strength between soft ferrite and hard martensite, tempered martensite, and retained austenite, and may be contained in a total of 15% or more from the viewpoint of bendability. More preferably, the total content is more preferably 20% or more.
- bainitic ferrite and bainite may contain only one or both.
- the volume fraction is preferably limited to 15% or less.
- the volume fraction of fresh martensite is more preferably 10% or less, and further preferably 5% or less.
- Tempered martensite is a structure that greatly improves the tensile strength, and may be contained in the structure of the base steel sheet in a volume fraction of 50% or less. From the viewpoint of tensile strength, the volume fraction of tempered martensite is preferably 10% or more. On the other hand, if the volume fraction of tempered martensite contained in the structure of the base steel plate exceeds 50%, it is not preferable because the yield stress is excessively increased and the shape freezeability is deteriorated.
- the structure of the base steel sheet of the high-strength galvanized steel sheet of the present invention may contain a structure other than the above, such as coarse cementite.
- coarse cementite increases in the structure of the base steel sheet, the bendability deteriorates. From this, the volume fraction of coarse cementite contained in the base steel sheet structure is preferably 10% or less, and more preferably 5% or less.
- the volume fraction of each structure contained in the base steel sheet of the high-strength galvanized steel sheet of the present invention can be measured by, for example, the following method.
- the volume fraction of retained austenite is X-ray diffracted using a plane parallel to the plate surface of the base steel sheet and a thickness of 1/4 as the observation surface, and the area fraction is calculated and taken as the volume fraction. Can do.
- the volume fraction of ferrite, pearlite, bainitic ferrite, bainite, tempered martensite and fresh martensite contained in the base steel sheet structure of the high-strength galvanized steel sheet of the present invention is perpendicular to the surface of the base steel sheet.
- a sample was taken with the cross section of the plate thickness parallel to the rolling direction (rolling direction) as the observation surface, and the observation surface was polished and nital etched, and the thickness was 1/8 to 3 centered on 1/4 of the plate thickness. / 8 thickness range is observed with a field emission scanning electron microscope (FE-SEM), the area fraction of each tissue is measured, and it is used to measure the volume fraction of each tissue. Can be considered.
- FE-SEM field emission scanning electron microscope
- the metal structure in the range of 1/8 thickness to 3/8 thickness centering on 1/4 of the thickness of the base steel sheet represents the overall structure of the base steel sheet.
- the base steel plate The entire metal structure can be certified.
- ferrite is a massive crystal grain and is an area where there is no iron-based carbide having a major axis of 100 nm or more.
- the volume fraction of ferrite is the sum of the volume fraction of ferrite remaining at the maximum heating temperature and the ferrite newly generated in the ferrite transformation temperature range.
- Bainitic ferrite is a collection of lath-like crystal grains and does not contain iron-based carbide having a major axis of 20 nm or more inside the lath.
- Bainite is a collection of lath-like crystal grains, and has a plurality of iron-based carbides having a major axis of 20 nm or more inside the lath, and further, these carbides are a single variant, that is, a group of iron-based carbides extending in the same direction. Belongs to.
- the iron-based carbide group extending in the same direction means that the difference in the extension direction of the iron-based carbide group is within 5 °.
- Tempered martensite is an aggregate of lath-like crystal grains, and has a plurality of iron-based carbides having a major axis of 20 nm or more inside the lath, and further, these carbides are a plurality of variants, that is, a plurality of iron-based materials extending in different directions. It belongs to the carbide group. Note that bainite and tempered martensite can be easily distinguished by observing the iron-based carbide inside the lath-like crystal grains using FE-SEM and examining the elongation direction.
- the high-strength galvanized steel sheet of the present invention has a kurtosis K * of ⁇ 0.30 or less in a hardness distribution within a predetermined range of the base steel sheet.
- the hardness distribution in the high-strength galvanized steel sheet of the present invention is determined as follows. That is, a plurality of measurement regions having a diameter of 1 ⁇ m or less are set in the range of 1/8 to 3/8 thickness of the base steel plate, and the hardness in the plurality of measurement regions is measured. Then, the hardness distribution is obtained by arranging the measurement values in each measurement region in ascending order.
- the hardness of the N0.02th largest measured value from the measured value of the minimum hardness is set to 2% hardness.
- the hardness of the N0.98th largest measured value from the measured value of the minimum hardness is set to 98% hardness.
- the kurtosis K * in the hardness distribution between the 2% hardness and the 98% hardness is set in a range of ⁇ 0.30 or less.
- 1000 measurement areas with a diameter of 1 ⁇ m or less are set, and when the hardness in the measurement area is measured at these 1000 positions, The total number of hardness measurements is 1000.
- the hardness distribution is obtained by arranging the measured values of hardness measured in each of these 1000 measurement regions in ascending order.
- the hardness of the measured value N0.02 that is, the twentieth
- the hardness of the N0.98th (ie, 980th) largest measured value from the measured value of the minimum hardness is 98% hardness.
- the hardness measurement position is in the range of 1/8 to 3/8 thickness of the base steel plate, centering on 1/4 of the thickness in the cross section of the thickness parallel to the rolling direction of the base steel plate.
- the total number of hardness measurement values is in the range of 100 to 10,000, preferably 1000 or more.
- the high-strength galvanized steel sheet according to the present invention has a kurtosis K * of the hardness distribution between the above-mentioned 2% hardness and 98% hardness of ⁇ 0.30 or less, and variation in hardness distribution in the base steel sheet Is small. Therefore, the boundary where the areas having a large hardness difference contact each other is reduced, and excellent bendability is obtained.
- the kurtosis K * is preferably ⁇ 0.40 or less, and more preferably ⁇ 0.50 or less.
- the lower limit of the kurtosis K * is not particularly defined, and the effect of the present invention is exhibited. However, since it is difficult from experience to make K * ⁇ 1.20 or less, this is the lower limit.
- the kurtosis K * may be more than ⁇ 0.40, for example, about ⁇ 0.35 to ⁇ 0.38.
- the kurtosis K * is a number obtained by the following formula from data of hardness measurement values in a plurality of measurement regions, and is a numerical value evaluated by comparing the frequency distribution of data with a normal distribution.
- the kurtosis is a negative number, it means that the frequency distribution curve of the data is relatively flat, and the larger the absolute value is, the more out of the normal distribution.
- Hi represents the hardness of the i-th largest measurement point from the measurement value of the minimum hardness
- H * represents the N0.98th largest measurement point from the minimum hardness N0.02- S * indicates the standard deviation from the smallest hardness to the N0.02th largest measurement point to the N0.98th largest measurement point.
- the high-strength galvanized steel sheet of the present invention is a ratio of the Vickers hardness of the surface layer of the base steel sheet and the Vickers hardness of 1/4 thickness of the base steel sheet ((Vickers hardness of the surface layer) / (1/4 thickness). Vickers hardness) of 0.35 to 0.70.
- “the Vickers hardness of the surface layer of the base steel plate” means the Vickers hardness of the portion having entered 10 ⁇ m from the interface between the surface of the base steel plate and the galvanized layer to the base steel plate side. .
- the Vickers hardness of the surface layer of the base steel plate and the 1/4 thickness Vickers hardness of the base steel plate can be measured by the following methods. That is, at least 1 mm in the rolling direction of the base steel plate at a location where 10 ⁇ m is entered from the interface between the surface of the base steel plate and the alloyed galvanized layer to the base steel plate side and a quarter thickness of the base steel plate Vickers hardness is measured at five points apart, the maximum and minimum values are discarded, and the average of the remaining three points is taken. In the measurement of Vickers hardness, the load is 100 gf.
- the ratio of the Vickers hardness of the surface layer of the base steel sheet to the 1/4 thickness Vickers hardness of the base steel sheet is within the above range. Is sufficiently lower than the Vickers hardness of 1/4 thickness, and the surface layer of the base steel sheet has a microstructure with excellent ductility. For this reason, when the high-strength galvanized steel sheet is bent, necking on the base steel sheet side at the interface between the surface of the base steel sheet and the alloyed galvanized layer is prevented. Necking at the interface with the plating layer hardly occurs.
- the ratio of the Vickers hardness of the surface layer of the base steel plate to the 1/4 thickness Vickers hardness of the base material steel plate exceeds 0.70, the surface layer of the base material steel plate is hard and sufficiently prevents the surface of the base steel plate from being necked. Since it cannot do, bendability becomes inadequate. In order to obtain more excellent bendability, it is preferable that the ratio of the Vickers hardness of the surface layer of the base steel plate to the 1/4 thickness Vickers hardness of the base steel plate is 0.60 or less. Moreover, stretch flangeability will deteriorate that ratio of the Vickers hardness of the surface layer of a base material steel plate and the Vickers hardness of 1/4 thickness of a base material steel plate is less than 0.35. In order to obtain good stretch flangeability, the ratio of the Vickers hardness of the surface layer of the base steel plate to the 1/4 thickness Vickers hardness of the base steel plate is preferably 0.38 or more.
- an alloyed galvanized layer is formed on the surface of the base steel sheet.
- the alloyed galvanized layer is mainly composed of an Fe—Zn alloy formed by diffusing Fe in steel during galvanization by an alloying reaction, and the content of iron in the alloyed galvanized layer is 8% by mass. ⁇ 12%.
- the alloyed galvanized layer is sufficiently destroyed and peeled off when bent to a high-strength galvanized steel sheet. Can be prevented.
- the iron content of the alloyed galvanized layer is 8.0% or more in order to ensure good flaking resistance, and preferably 9.0% or more. Further, the iron content in the alloyed galvanized layer is set to 12.0% or less in order to ensure good powdering resistance, and is preferably 11.0% or less. Further, the alloyed galvanized layer may contain Al as an impurity.
- the alloyed galvanized layer is one or two of Pb, Sb, Si, Sn, Mg, Mn, Ni, Cr, Co, Ca, Cu, Li, Ti, Be, Bi, Sr, I, Cs, and REM. These may be contained or they may be mixed. Even if the alloyed galvanized layer contains or is mixed with one or more of the above elements, the effects of the present invention are not impaired, and depending on the content, the corrosion resistance and workability are improved. In some cases, it is preferable.
- the amount of adhesion of the alloyed galvanized layer is preferably 20 g / m 2 or more from the viewpoint of corrosion resistance and 150 g / m 2 or less from the viewpoint of economy.
- the average thickness of the alloyed galvanized layer is 1.0 ⁇ m or more and 50 ⁇ m or less. If it is less than 1.0 ⁇ m, sufficient corrosion resistance cannot be obtained. Preferably, it is 2.0 ⁇ m or more. On the other hand, if it exceeds 50.0 ⁇ m, the strength of the steel sheet is impaired. From the viewpoint of raw material cost, the thickness of the alloyed galvanized layer is preferably as thin as possible, and is preferably 30.0 ⁇ m or less.
- a film made of phosphorus oxide and a film made of complex oxide containing phosphorus may be formed on the surface of the alloyed galvanized layer.
- a steel sheet to be a base steel sheet is first manufactured.
- a slab having the above-described chemical component (composition) is cast. And it heats to 1050 degreeC or more, completes hot rolling at the finishing hot rolling temperature of 880 degreeC or more, and performs the hot rolling process wound up in the temperature range of 750 degrees C or less.
- a slab manufactured by a continuous casting slab or a thin slab caster can be used as the slab used for the hot rolling process.
- the method for producing a high-strength galvanized steel sheet according to the present invention is suitable for a process such as continuous casting-direct rolling (CC-DR) in which hot rolling is performed immediately after casting.
- the slab heating temperature needs to be 1050 ° C. or higher. If the slab heating temperature is excessively low, the finish rolling temperature falls below the Ar 3 transformation point, and rolling in a two-phase region of ferrite and austenite is performed. Thereby, a mixed grain structure in which the hot-rolled sheet structure is inhomogeneous is generated, and even if the cold-rolling process and the continuous annealing process are performed, the inhomogeneous structure is not eliminated, and the base steel sheet is inferior in ductility and bendability. In addition, the decrease in the slab heating temperature may cause an excessive increase in rolling load, which may make rolling difficult and may cause a shape defect of the base steel sheet after rolling.
- the upper limit of the slab heating temperature is not particularly defined, and the effect of the present invention is exhibited. However, since it is not economically preferable to make the heating temperature excessively high, the upper limit of the slab heating temperature is 1350 ° C. or less. It is desirable.
- the Ar 3 transformation point is calculated by the following formula.
- Ar 3 901-325 ⁇ C + 33 ⁇ Si-92 ⁇ (Mn + Ni / 2 + Cr / 2 + Cu / 2 + Mo / 2) + 52 ⁇ Al
- C, Si, Mn, Ni, Cr, Cu, Mo, and Al are content [mass%] of each element. When it does not contain an element, it is calculated as 0.
- the finishing hot rolling temperature needs to be 880 ° C. or higher. If the finish hot rolling temperature is less than 880 ° C., the rolling load at the time of finish rolling becomes high and hot rolling becomes difficult, or the hot rolled steel sheet obtained after hot rolling may have a defective shape. There is. Moreover, it is preferable that the finishing hot rolling temperature of hot rolling is not less than the Ar 3 transformation point. If the finishing hot rolling temperature is less than the Ar 3 point temperature, the hot rolling becomes a two-phase rolling of ferrite and austenite, and the structure of the hot rolled steel sheet may become a heterogeneous mixed grain structure. On the other hand, the upper limit of the finishing hot rolling temperature is not particularly defined, and the effect of the present invention is exhibited. However, when the finishing hot rolling temperature is excessively high, the slab heating temperature is excessively high in order to secure the temperature. Must be. For this reason, it is desirable that the upper limit temperature of the finish hot rolling temperature is 1000 ° C. or less.
- the coiling temperature is set to 750 ° C. or lower.
- the winding temperature is preferably 720 ° C. or lower, and more preferably 700 ° C. or lower.
- the coiling temperature is set to 500 ° C. or higher.
- the winding temperature is preferably 550 ° C. or higher, more preferably 600 ° C. or higher.
- pickling removes oxides on the surface of the hot-rolled steel sheet, and is therefore important for improving the plateability of the base steel sheet. Moreover, pickling may be performed once or may be performed in a plurality of times.
- the hot-rolled steel sheet after pickling may be subjected to the continuous annealing process as it is, but a cold-rolling process may be performed on the hot-rolled steel sheet that has been pickled for the purpose of adjusting the plate thickness or correcting the shape.
- a cold-rolling process may be performed on the hot-rolled steel sheet that has been pickled for the purpose of adjusting the plate thickness or correcting the shape.
- the rolling reduction in the cold rolling process is preferably 40% or more, and more preferably 45% or more.
- the rolling reduction exceeds 75%, the cold rolling load becomes too large and it becomes difficult to cold rolling. For this reason, the rolling reduction is preferably 75% or less. From the viewpoint of cold rolling load, the rolling reduction is more preferably 70% or less.
- the effects of the present invention can be exhibited without particularly defining the number of rolling passes and the rolling reduction for each rolling pass.
- a continuous annealing process is performed in which the hot rolled steel sheet obtained after the hot rolling process or the cold rolled steel sheet obtained after the cold rolling process is passed through a continuous annealing line.
- the steel sheet is heated at an average heating rate of 1 ° C./second or more in the temperature range between 600 ° C. and Ac 1 transformation point.
- the hot rolled steel sheet obtained after the hot rolling process or the cold rolled steel sheet obtained after the cold rolling process has a temperature range between 600 ° C. and Ac 1 transformation point of 1 ° C. / Heated at an average heating rate of at least seconds.
- the temperature of the steel plate reaches 600 ° C. or higher, decarburization from the steel plate is started. In the temperature range between 600 ° C.
- the iron contained in the steel sheet is the same bcc iron inside and on the surface.
- bcc iron is a general term for ferrite, bainite, bainitic ferrite, and martensite having a body-centered cubic lattice.
- the average heating rate in the temperature range between 600 ° C. and Ac 1 transformation point is preferably 2 ° C./second or more.
- the upper limit of the average heating rate between 600 ° C. and Ac 1 transformation point is not particularly limited, but is preferably 100 ° C./second or less from the viewpoint of cost.
- the microstructure of the surface layer of the steel sheet is bcc iron and the microstructure of the central part of the steel sheet is austenite.
- Austenite can dissolve more carbon than bcc iron. For this reason, carbon is difficult to diffuse from austenite to bcc iron, and easily diffuses from bcc iron to the outside or austenite. Therefore, at the annealing temperature, the carbon at the center of the steel plate stays at the center, a part of the carbon on the surface layer of the steel plate diffuses into the center, and the rest escapes from the outermost layer. As a result, the steel sheet has a distribution in which the amount of carbon in the central portion is greater than that of the surface layer.
- the annealing temperature is preferably (Ac 1 transformation point +50) ° C. or higher, more preferably (Ac 1 transformation point +40) ° C. or higher.
- the annealing temperature is preferably (Ac3-10) ° C. or lower, and more preferably (Ac3-15) ° C. or lower.
- the atmosphere during annealing is log (moisture pressure / hydrogen partial pressure) of ⁇ 3.0 to 0.0.
- log moisture pressure / hydrogen partial pressure
- the logarithm of the ratio between the water pressure and the hydrogen partial pressure is moderately promoted.
- the logarithm of the ratio between the moisture pressure and the hydrogen partial pressure is less than ⁇ 3.0, decarburization from the steel sheet surface layer by annealing is insufficient.
- the logarithm of the ratio of moisture pressure to hydrogen partial pressure is preferably ⁇ 2.5 or more.
- the logarithm of the ratio between the moisture pressure and the hydrogen partial pressure is preferably ⁇ 0.5 or less.
- the atmosphere at the time of annealing contains nitrogen, water vapor
- the residence time in the above-described annealing temperature and atmosphere is 20 to 600 seconds. If the residence time is less than 20 seconds, the amount of carbon that diffuses from bcc iron to the outside or austenite becomes insufficient. In order to ensure the amount of carbon diffusing from bcc iron, the residence time is preferably 35 seconds or more, and more preferably 50 seconds or more. Moreover, when said residence time exceeds 600 second, the quantity of carbon which escapes from the outermost surface layer will increase, and the hardness of surface layer will fall too much. In order to ensure the hardness of the surface layer, the residence time is preferably 450 seconds or less, and more preferably 300 seconds or less.
- the bend-unbend deformation process is performed twice or more using a roll having a radius of 800 mm or less at the annealing temperature and the above atmosphere, and the difference between the accumulated strain amounts on the front and back surfaces is set to 0.0050 or less.
- strain is introduced into the surface layer of the steel plate that becomes the base steel plate, and the outermost surface layer is efficiently transformed into bcc iron.
- the difference between the cumulative strain amounts on the front and back surfaces is 0.0050 or less, the deviation in the bendability on the front and back surfaces of the base steel sheet of the galvanized steel sheet finally obtained is sufficiently small. .
- the base steel plate of the galvanized steel plate finally obtained also has different bendability on the front and back surfaces, which is not preferable.
- the number of bending-bending deformation processes is not particularly limited, but if the cumulative strain amount on the front and back surfaces of the steel sheet exceeds 0.100, the shape of the steel sheet cannot be maintained, so the cumulative strain amount on the front and back surfaces is 0.
- the range is preferably 100 or less.
- the roll used in the bending-unbending deformation process has a radius of 800 mm or less. By setting the roll radius to 800 mm or less, strain can be easily introduced into the surface layer of the steel sheet. If the roll radius exceeds 800 mm, sufficient strain cannot be introduced into the surface of the steel sheet, and the surface layer will not be transformed into bcc iron, so the surface layer hardness will not be sufficiently low.
- the amount of strain that can be entered in one bending operation outside the bending is limited to a range of 0.0007 to 0.091 in terms of tensile strain.
- the amount of strain that is entered in one bending process is preferably 0.0010 or more on the outside of the bending. If the amount of strain that enters the outside of the bend in one process exceeds 0.091, the shape of the steel sheet cannot be maintained. From this point of view, the amount of strain that enters the outside of the bend in one processing is preferably 0.050 or less, and more preferably 0.025 or less.
- the ferrite transformation progresses in the surface layer of the steel sheet by bending-unbending deformation near the maximum temperature of annealing, but the ferrite transformation is delayed in the steel sheet with a small strain, and the austenite ratio increases, and the surface layer and the internal (1 / 4 thickness) hardness.
- the thickness of the steel sheet is desirably 0.6 mm or more and 5.0 mm or less. If it is less than 0.6 mm, it is difficult to maintain the shape of the steel sheet. If it exceeds 5.0 mm, it is difficult to control the temperature of the steel sheet, and the desired characteristics cannot be obtained.
- the roll diameter exceeds 800 mm, sufficient strain cannot be introduced into the surface layer of the steel sheet.
- the lower limit of the roll diameter is not particularly defined, but if a roll of less than 50 mm is used, the maintenance cost of the equipment increases, so 50 mm or more is preferable.
- the steel plate after the bending-bending deformation process is cooled at an average cooling rate of 1.0 to 5.0 ° C./second in a temperature range of 740 ° C. to 650 ° C.
- ferrite as bcc iron is generated in the microstructure of the central part of the steel sheet, and part of C is diffused from the central part of the steel sheet to the surface layer part.
- the difference in C content between the central portion of the steel sheet and the surface layer is reduced, and the distribution of the C content in the steel sheet is equal to the Vickers hardness of the surface layer in the base steel sheet of the high-strength galvanized steel sheet of the present invention. It corresponds to the range of the ratio of the Vickers hardness of 4 thickness “(surface Vickers hardness) / (1 ⁇ 4 thickness Vickers hardness)”.
- the average cooling rate in the temperature range of 740 ° C. to 650 ° C. is less than 1.0 ° C./second, the residence time in the temperature range of 740 ° C. to 650 ° C. is long and a large amount of ferrite is generated. For this reason, the diffusion of C from the central part of the steel sheet to the surface layer part is promoted, and the difference between the hardness of the central part of the steel sheet and the hardness of the surface layer becomes insufficient. If the average cooling rate in the temperature range of 740 ° C. to 650 ° C. exceeds 5.0 ° C./second, the amount of ferrite generated in the microstructure of the central portion of the steel sheet is insufficient, The density difference in the amount of C from the surface layer is too large.
- the steel sheet is cooled at an average cooling rate of 5 to 200 ° C./second in a temperature range of 650 ° C. to 500 ° C.
- the average cooling rate in the temperature range of 650 ° C. to 500 ° C. is less than 5 ° C./second, a large amount of pearlite and / or iron-based carbide is generated, and thus the retained austenite becomes insufficient.
- the average cooling rate is preferably 7.0 ° C./second or more, and more preferably 8.0 ° C./second or more.
- the upper limit of the average cooling rate in the temperature range of 650 ° C. to 500 ° C. is not particularly defined, and the effect of the present invention is exhibited.
- special equipment is required for the average cooling rate to exceed 200 ° C./second. From the viewpoint of cost, the upper limit of the cooling rate is set to 200 ° C./second.
- the steel plate is stopped for 15 to 1000 seconds in a temperature range of 500 ° C. to 400 ° C.
- the steel plate used as a base material steel plate obtains a preferable amount of retained austenite, bainite and / or bainitic ferrite.
- the bainite transformation proceeds excessively and the C concentration into the retained austenite proceeds, so that a large amount of retained austenite remains, making it difficult to reduce the volume fraction of retained austenite to 8% or less.
- the retention time in the temperature range of 500 ° C. to 400 ° C. exceeds 1000 seconds, the coarse iron-based carbide that acts as a starting point of fracture is generated and grows, so that the bendability is greatly deteriorated.
- the high-strength galvanized steel sheet of the present invention is formed in which the surface of the base steel sheet includes the Zn—Fe alloy and the alloyed galvanized layer having an iron content of 8 to 12% is formed.
- the higher the carbon content of the base steel sheet the lower the iron content in the alloyed galvanized layer and the lower the adhesion between the base steel sheet and the galvanized layer. It becomes.
- the present invention in order to obtain a high-strength galvanized steel sheet having a maximum tensile strength of 900 MPa or more, a large amount of carbon, which is an element for improving the strength, is contained.
- the carbon concentration of the surface layer of the cold-rolled steel sheet that becomes the base steel sheet obtained after the continuous annealing process is low, the iron content is 8 to 12% in the plating alloying process. An excellent alloyed galvanized layer is formed.
- the galvanizing bath is not particularly limited, and Pb, Sb, Si, Sn, Mg, Mn, Ni, Cr, Co, Ca, Cu, Li, Ti, Be, Bi, Sr are contained in the galvanizing bath. Even if one, two or more of I, Cs, and REM are mixed, the effect of the present invention is not impaired, and depending on the amount, corrosion resistance and workability may be improved. Moreover, Al may be contained in the galvanizing bath. In this case, the Al concentration in the bath is preferably 0.05% or more and 0.15% or less.
- the temperature for the alloying treatment is preferably 480 to 560 ° C., and the residence time for the alloying treatment is preferably 15 to 60 seconds.
- the alloy is retained for 30 to 1000 seconds at a temperature of 200 to 350 ° C. after the alloying treatment.
- the base steel sheet structure of the high-strength galvanized steel sheet contains tempered martensite.
- the base steel sheet structure of the high-strength galvanized steel sheet has retained austenite, ferrite, bainite and / or bainitic ferrite, tempered martensite, and by having such a base steel sheet structure, The kurtosis K * of the hardness distribution described above is ⁇ 0.30 or less.
- the steel plate after the alloying treatment is cooled to 350 ° C. or lower to generate martensite, and then 350 ° C. or higher.
- Tempered martensite may be generated by reheating to a temperature range of 550 ° C. or lower and retaining for 2 seconds or longer. Further, the steel sheet cooled to a temperature range of 500 ° C. or lower in the continuous annealing process is further cooled to 350 ° C. or lower to generate martensite, and then reheated and retained at 400 to 500 ° C. Tempered martensite is generated in the steel sheet structure.
- the high-strength galvanized steel sheet cooled to room temperature may be cold-rolled at a rolling reduction of 0.05 to 3.00% for shape correction.
- the present invention is not limited to the above example.
- a film made of a phosphorus oxide and / or a composite oxide containing phosphorus can function as a lubricant when processing a steel sheet, and can protect an alloyed galvanized layer formed on the surface of the base steel sheet. it can.
- the Ac 1 transformation point temperature and the Ac 3 transformation point temperature in Tables 8 to 11 are the values when a small piece is cut out from the steel sheet treated under the conditions of Tables 4 to 7 and heated at 10 ° C./second before the annealing treatment.
- the volume expansion curve was measured and determined.
- the temperature range between 600 ° C. and Ac 1 transformation point is passed at the average heating rate described in Table 8 to Table 11, and heated to the maximum heating temperature (annealing temperature) described in Table 8 to Table 118.
- Moisture pressure and hydrogen partial pressure (log (PH 2 O / PH 2 )) were controlled under the conditions described in Tables 8 to 11 in an atmosphere mainly composed of nitrogen, and the residence times described in Tables 8 to 11 (continuous annealing).
- the decarburization treatment was performed for the residence time).
- the larger strain amount among the total strain amounts introduced into the front and back surfaces of the steel sheet is shown as the maximum total strain.
- the thickness of the steel sheet was changed to 0.70 to 8.00 mm.
- ⁇ described in Tables 8 to 11 represents the amount of strain introduced by performing bending-unbending deformation processing for each of the front and back surfaces of the steel sheet, and shows the absolute value of the difference. .
- the steel sheet after cooling was retained at a temperature range of 500 to 400 ° C. for a retention time described in Tables 8 to 11 (residence time between the continuous annealing step and the alloying treatment). Thereafter, the steel sheet was immersed in a galvanizing bath and subjected to an alloying treatment for staying at the temperatures shown in Tables 8 to 11 for the residence times shown in Tables 8 to 11. After the alloying treatment, the alloy was retained in the temperature range of 200 to 350 ° C. for the residence times described in Tables 8 to 11 (residence time for the alloying treatment).
- Example 7 to 34 After cooling to room temperature, in Examples 7 to 34, cold rolling was performed at a reduction rate of 0.15%, in Example 53, cold rolling was performed at a reduction rate of 1.50%, and in Example 54, the reduction rate was 1.00. %, And under conditions 61 to 100, cold rolling was performed at a rolling reduction of 0.25%. Thereafter, in Experimental Examples 9 and 49, a film made of a complex oxide containing P was applied to the surface layer of the galvanized steel sheet.
- Experimental Examples 9 and 49 are examples in which a film made of a complex oxide containing P is provided on the surface of an alloyed hot-dip galvanized steel sheet, and a high-strength alloyed hot-dip galvanized steel sheet having excellent formability is obtained.
- the amount of retained austenite is measured by X-ray diffraction, and the others are obtained by cutting out a plate thickness section parallel to the rolling direction of the steel sheet, etching the mirror-polished section with nital, and field emission scanning type. This was determined by observation using an electron microscope (FE-SEM: Field Emission Scanning Electron Microscope). Moreover, the iron content in 1/2 thickness of an alloying zinc plating layer was measured using EDX. The results are shown in Tables 12 to 15.
- the hardness of Experimental Examples 1 to 109 and 201 to 218 was measured by the method described below. The results are shown in Tables 16-19.
- the Vickers hardness was measured at five locations separated from each other by 1 mm or more in the rolling direction, the maximum value and the minimum value were discarded, and the average value of the remaining three points was obtained.
- the load was set to 100 gf.
- the Vickers hardness of the surface layer was measured on a line entering 40 ⁇ m from the interface between the alloyed galvanized layer and the base steel plate to the base steel plate side.
- the kurtosis K * of the hardness distribution was calculated using the result of measuring the hardness at an indentation load of 1 g using an indentation depth measurement method using a dynamic microhardness meter equipped with a Belkovic type triangular pan indenter. .
- the measurement position of hardness is 1/8 to 3/8 thickness centering on 1/4 of the plate thickness in the plate thickness section perpendicular to the plate surface of the steel plate and parallel to the rolling direction (rolling direction). The range.
- the total number of hardness measurements was 1000.
- Tables 20 to 23 show the results of evaluating the characteristics of the steel sheets of Experimental Examples 1 to 109 and 201 to 218 by the method described below.
- Tensile test pieces in accordance with JIS Z 2201 were collected from the steel sheets of Experimental Examples 1 to 109 and 201 to 218, and the tensile test was conducted in accordance with JIS Z 2241. Yield stress “YS”, tensile strength “TS”, all The elongation “EL” was measured. Further, a hole expansion test (JFST1001) for evaluating the flange property was performed, and a hole expansion limit value “ ⁇ ”, which is an index of stretch flangeability, was calculated. Moreover, the 90 degree
- a test piece of 35 mm ⁇ 100 mm was cut out from the steel plates of Experimental Examples 1 to 109, the shear cut surface was mechanically ground, and the bending radius was evaluated as twice the plate thickness. And the thing which became a predetermined
- the presence or absence of cracks, necking, and plating peeling was individually evaluated by visual inspection, and those that were completely absent were evaluated as acceptable ( ⁇ ) and those that were not acceptable were evaluated as unacceptable (x).
- Experimental Example 94 is an example in which the completion temperature of hot rolling is low, and the microstructure becomes inhomogeneous in one direction, so that ductility, stretch flangeability and bendability are inferior.
- Experimental example 98 is an example in which the temperature taken up by the coil after hot rolling is high, and the microstructure is very coarse, so that the ductility, stretch flangeability and bendability are inferior.
- Experimental Example 6 is an example in which the heating rate in the annealing process is slow, and the decarburization of the steel sheet has progressed and the hardness of the surface layer has greatly decreased, so that the stretch flangeability and bendability are inferior.
- Experimental Example 11 is an example in which the maximum heating temperature in the annealing process is low, and includes a large number of coarse iron-based carbides that are the starting points of fracture, so that ductility, stretch flangeability, and bendability are inferior.
- Experimental Example 12 is an example in which the maximum heating temperature in the annealing process is high, and since the volume fraction of retained austenite that is the starting point of fracture is large, stretch flangeability and bendability are inferior.
- Experimental Example 17 is an example in which the residence time in the decarburization temperature range is short, and the bendability is inferior because the hardness of the surface layer is excessively high.
- Experimental Example 18 is an example in which the residence time in the decarburization temperature range is long, and the hardness of the surface layer is excessively lowered, so that the stretch flangeability and bendability are inferior.
- Experimental Example 23 is an example in which the partial pressure of water vapor in the atmosphere in the decarburization treatment temperature range is high, and the bendability is inferior because the hardness of the surface layer is excessively reduced.
- Experimental Example 24 is an example in which the partial pressure of water vapor in the atmosphere in the decarburization temperature range is low, and the bendability is inferior because the hardness of the surface layer is excessively high.
- Experimental examples 28 and 29 are examples in which the difference in total strain introduced into the front and back surfaces, ⁇ , is large in the decarburization temperature range, and the bendability is inferior.
- Experimental Example 33 is an example in which the average cooling rate at 740 ° C. to 650 ° C. is low, and since the kurtosis in the hardness distribution inside the steel sheet is large, stretch flangeability and bendability are inferior.
- Experimental Example 34 is an example having a high average cooling rate of 740 ° C. to 650 ° C., and the kurtosis in the hardness distribution inside the steel sheet is large, so the ductility and bendability are inferior.
- Experimental Example 5 is an example in which the average cooling rate at 650 ° C. to 500 ° C. is low, the hardness difference between the steel sheet surface layer and the inside is small, a large amount of iron-based carbides are formed, and the bendability is inferior.
- Experimental Example 38 is an example in which the alloying treatment temperature of the plating layer is high, Fe% in the plating layer is excessive, and coarse iron-based carbides that become the starting point of fracture are generated inside the steel sheet, so that ductility, elongation Flangeability and bendability are inferior.
- Experimental Example 39 is an example in which the alloying temperature of the plating layer is low, Fe% in the plating layer is insufficient, and the bendability is inferior.
- Experimental Example 43 is an example in which the alloying time of the plating layer is short, Fe% in the plating layer is insufficient, and the bendability is inferior.
- Experimental Example 44 is an example in which the alloying time of the plating layer is long, and because coarse iron-based carbides that become the starting point of fracture are generated inside the steel sheet, the ductility, stretch flangeability, and bendability are inferior.
- the plate thickness of the steel plate was extremely thin, the flatness of the steel plate could not be maintained, and a predetermined characteristic evaluation test could not be performed.
- Experimental example 206 is an example in which the difference in total strain introduced on the front and back surfaces, ⁇ , is large, and the bendability is inferior.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Crystallography & Structural Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Coating With Molten Metal (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
Description
の析出物を100個/μm2以上含有する鋼組織を有し、引張強度が540MPa以上である溶融亜鉛めっき鋼板が記載されている。
以上のような現状に鑑み、本発明は、優れた曲げ性を有する高強度亜鉛めっき鋼板およびその製造方法を提供するものである。
また、このような高強度亜鉛めっき鋼板は、母材鋼板の表層のビッカース硬さが1/4厚のビッカース硬さと比較して低く、母材鋼板の表層の延性が優れているものであるので、曲げ加工を行った場合における母材鋼板の表面と合金化亜鉛めっき層との界面における母材鋼板側のネッキングが防止され、母材鋼板の表面と合金化亜鉛めっき層との界面でのネッキングが生じにくい。
本発明は、かかる知見に基づいて完成させたものであり、その要旨とするところは以下の通りである。
質量%で、C:0.075~0.300%、Si:0.30~2.50%、Mn:1.30~3.50%、P:0.001~0.050%、S:0.0001~0.0100%、Al:0.005~1.500%、N:0.0001~0.0100%、O:0.0001~0.0100%、を含有し、残部が鉄および不可避的不純物からなる母材鋼板の表面に、合金化亜鉛めっき層が形成されてなる引張最大強度900MPa以上の高強度亜鉛めっき鋼板であり、前記母材鋼板の1/8厚~3/8厚の範囲において、残留オーステナイトが体積分率で8%以下に制限され、前記母材鋼板の1/8厚~3/8厚の範囲において、直径1μm以下の測定領域を複数設定して、前記複数の測定領域における硬度の測定値を小さい順に並べて硬度分布を得るとともに、硬度の測定値の全数に0.02を乗じた数であって該数が小数を含む場合はこれを切り上げて得た整数N0.02を求め、最小硬度の測定値からN0.02番目に大きな測定値の硬度を2%硬度とし、また、硬度の測定値の全数に0.98を乗じた数であって該数が小数を含む場合はこれを切り下げて得た整数N0.98を求め、最小硬度の測定値からN0.98番目に大きな測定値の硬度を98%硬度としたとき、前記2%硬度と前記98%硬度の間における前記硬度分布の尖度K*が-0.30以下であり、前記母材鋼板の表層のビッカース硬さと、前記母材鋼板の1/4厚のビッカース硬さの比が0.35~0.70であり、前記合金化亜鉛めっき層の鉄の含有量が、質量%で8~12%である、曲げ性に優れた高強度亜鉛めっき鋼板。
前記母材鋼板の組織が、前記母材鋼板の1/8厚~3/8厚の範囲において、体積分率で10~75%のフェライトと、合計で10~50%のベイニティックフェライトとベイナイトのいずれか一方もしくは両方と、10~50%の焼戻しマルテンサイトとを含み、フレッシュマルテンサイトが体積分率で15%以下に制限され、パーライトが体積分率で5%以下に制限された、(1)に記載の曲げ性に優れた高強度亜鉛めっき鋼板。
前記母材鋼板がさらに、質量%で、Ti:0.005~0.150%、Nb:0.005~0.150%の1種または2種を含有する、(1)に記載の曲げ性に優れた高強度亜鉛めっき鋼板。
前記母材鋼板がさらに、質量%で、B:0.0001~0.0100%、Cr:0.01~2.00%、Ni:0.01~2.00%、Cu:0.01~2.00%、Mo:0.01~1.00%、W:0.01~1.00%の1種または2種以上を含有する、(1)に記載の曲げ性に優れた高強度亜鉛めっき鋼板。
前記母材鋼板がさらに、質量%で、V:0.005~0.150%含有する、(1)に記載の曲げ性に優れた高強度亜鉛めっき鋼板。
前記母材鋼板がさらに、Ca、Ce、Mg、Zr,Hf、REMの1種または2種以上を合計で0.0001~0.5000質量%含有する、(1)に記載の曲げ性に優れた高強度亜鉛めっき鋼板。
前記熱間圧延工程後、前記連続焼鈍工程の前に、30~75%の圧下率で冷延する冷間圧延工程を行う、(8)に記載の曲げ性に優れた高強度亜鉛めっき鋼板の製造方法。
前記合金化処理工程後に、200~350℃の温度で30~1000秒滞留する、(8)に記載の曲げ性に優れた高強度亜鉛めっき鋼板の製造方法。
前記合金化処理工程後に、リン酸化物および/またはリンを含む複合酸化物からなる皮膜を付与する工程を行う、(8)に記載の耐衝撃特性に優れた高強度亜鉛めっき鋼板の製造方法。
まず、本発明の高強度亜鉛めっき鋼板を構成する母材鋼板の化学成分(組成)について説明する。なお、以下の説明における[%]は[質量%]である。
Cは、母材鋼板の強度を高めるために含有される。しかし、Cの含有量が0.300%を超えると溶接性が不十分となる。溶接性の観点から、Cの含有量は0.250%以下であることが好ましく、0.220%以下であることがより好ましい。一方、Cの含有量が0.075%未満であると強度が低下し、900MPa以上の引張最大強度を確保することが出来ない。強度を高めるため、Cの含有量は0.090%以上であることが好ましく、0.100%以上であることがより好ましい。
Siは、母材鋼板における鉄系炭化物の生成を抑制し、強度と成形性を高めるために必要な元素である。また、固溶強化元素として、母材鋼板の表層の硬さを高めるため、伸びフランジ性を向上させる元素である。しかし、Siの含有量が2.50%を超えると母材鋼板が脆化し、延性が劣化する。延性の観点から、Siの含有量は2.20%以下であることが好ましく、2.00%以下であることがより好ましい。一方、Siの含有量が0.30%未満では合金化亜鉛めっき層の合金化処理中に粗大な鉄系炭化物が多量に生成し、強度および成形性が劣化する。この観点から、Siの下限値は0.50%以上であることが好ましく、0.70%以上がより好ましい。
Mnは、母材鋼板の強度を高めるために含有される。しかし、Mnの含有量が3.50%を超えると母材鋼板の板厚中央部に粗大なMn濃化部が生じ、脆化が起こりやすくなり、鋳造したスラブが割れるなどのトラブルが起こりやすい。また、Mnの含有量が3.50%を超えると溶接性も劣化する。したがって、Mnの含有量は、3.50%以下とする必要がある。溶接性の観点から、Mnの含有量は3.20%以下であることが好ましく、3.00%以下であることがより好ましい。一方、Mnの含有量が1.30%未満であると、焼鈍後の冷却中に軟質な組織が多量に形成されるため、900MPa以上の引張最大強度を確保することが難しくなる。このことから、Mnの含有量を1.30%以上とする必要がある。Mnの含有量は、さらに強度を高めるために、1.50%以上であることが好ましく、1.70%以上であることがより好ましい。
Pは母材鋼板の板厚中央部に偏析する傾向があり、溶接部を脆化させる。Pの含有量が0.050%を超えると溶接部が大幅に脆化するため、Pの含有量を0.050%以下に限定した。Pの含有量の下限は、特に定めることなく本発明の効果は発揮されるが、Pの含有量を0.001%未満とすることは製造コストの大幅な増加を伴うことから、0.001%を下限値とする。
Sは、溶接性ならびに鋳造時および熱延時の製造性に悪影響を及ぼす。このことから、Sの含有量の上限値を0.0100%以下とした。また、SはMnと結びついて粗大なMnSを形成して延性や伸びフランジ性を低下させるため、0.0050%以下とすることが好ましく、0.0025%以下とすることがより好ましい。Sの含有量の下限は、特に定めることなく本発明の効果は発揮されるが、Sの含有量を0.0001%未満とすることは製造コストの大幅な増加を伴うため、0.0001%を下限値とする。
Alは鉄系炭化物の生成を抑えて母材鋼板の強度および成形性を高める。しかし、Alの含有量が1.500%を超えると溶接性が悪化するため、Alの含有量の上限を1.500%とする。この観点から、Alの含有量は1.200%以下とすることが好ましく、0.900%以下とすることがより好ましい。また、Alは脱酸材としても有効な元素であるが、Alの含有量が0.005%未満では脱酸材としての効果が十分に得られないことから、Alの含有量の下限を0.005%以上とする。脱酸の効果を十分に得るにはAl量は0.010%以上とすることが好ましい。
Nは、粗大な窒化物を形成し、延性および伸びフランジ性を劣化させることから、添加量を抑える必要がある。Nの含有量が0.0100%を超えると、この傾向が顕著となることから、N含有量の範囲を0.0100%以下とした。また、Nは、溶接時のブローホール発生の原因になることから少ない方が良い。Nの含有量の下限は、特に定めることなく本発明の効果は発揮されるが、Nの含有量を0.0001%未満にすると、製造コストの大幅な増加を招くことから、0.0001%を下限値とする。
Oは、酸化物を形成し、延性および伸びフランジ性を劣化させることから、含有量を抑える必要がある。Oの含有量が0.0100%を超えると、伸びフランジ性の劣化が顕著となることから、O含有量の上限を0.0100%以下とした。Oの含有量は0.0080%以下であることが好ましく0.0060%以下であることがさらに好ましい。Oの含有量の下限は、特に定めることなく本発明の効果は発揮されるが、Oの含有量を0.0001%未満とすることは製造コストの大幅な増加を伴うため、0.0001%を下限とした。
「Ti:0.005~0.150%」
Tiは、析出物強化、フェライト結晶粒の成長抑制による細粒強化および再結晶の抑制を通じた転位強化にて、母材鋼板の強度上昇に寄与する元素である。しかし、Tiの含有量が0.150%を超えると、炭窒化物の析出が多くなり成形性が劣化するため、Tiの含有量は0.150%以下であることが好ましい。成形性の観点から、Tiの含有量は0.100%以下であることがより好ましく、0.070%以下であることがさらに好ましい。Tiの含有量の下限は、特に定めることなく本発明の効果は発揮されるが、Tiによる強度上昇効果を十分に得るにはTiの含有量は0.005%以上であることが好ましい。母材鋼板の高強度化には、Tiの含有量は0.010%以上であることがより好ましく、0.015%以上であることがさらに好ましい。
Nbは、析出物強化、フェライト結晶粒の成長抑制による細粒強化および再結晶の抑制を通じた転位強化にて、母材鋼板の強度上昇に寄与する元素である。しかし、Nbの含有量が0.150%を超えると、炭窒化物の析出が多くなり成形性が劣化するため、Nbの含有量は0.150%以下であることが好ましい。成形性の観点から、Nbの含有量は0.100%以下であることがより好ましく、0.060%以下であることがさらに好ましい。Nbの含有量の下限は、特に定めることなく本発明の効果は発揮されるが、Nbによる強度上昇効果を十分に得るにはNbの含有量は0.005%以上であることが好ましい。母材鋼板の高強度化には、Nbの含有量は0.010%以上であることがより好ましく、0.015%以上であることがさらに好ましい。
Bは高温での相変態を抑制し、高強度化に有効な元素であり、Cおよび/またはMnの一部に代えて添加してもよい。Bの含有量が0.0100%を超えると、熱間での加工性が損なわれ、生産性が低下する。このことから、Bの含有量は0.0100%以下であることが好ましい。生産性の観点から、Bの含有量は0.0050%以下であることがより好ましく、0.0030%以下であることがさらに好ましい。Bの含有量の下限は、特に定めることなく本発明の効果は発揮されるが、Bによる高強度化の効果を十分に得るには、Bの含有量を0.0001%以上とすることが好ましい。高強度化には、Bの含有量が0.0003%以上であることがより好ましく、0.0005%以上であることがより好ましい。
Crは高温での相変態を抑制し、高強度化に有効な元素であり、Cおよび/またはMnの一部に代えて添加してもよい。Crの含有量が2.00%を超えると、熱間での加工性が損なわれ、生産性が低下することから、Crの含有量は2.00%以下であることが好ましい。Crの含有量の下限は、特に定めることなく本発明の効果は発揮されるが、Crによる高強度化の効果を十分に得るには、Crの含有量は0.01%以上であることが好ましい。
Niは高温での相変態を抑制し、高強度化に有効な元素であり、Cおよび/またはMnの一部に代えて添加してもよい。Niの含有量が2.00%を超えると、溶接性が損なわれることから、Niの含有量は2.00%以下であることが好ましい。Niの含有量の下限は、特に定めることなく本発明の効果は発揮されるが、Niによる高強度化の効果を十分に得るには、Niの含有量は0.01%以上であることが好ましい。
Cuは微細な粒子として鋼中に存在することで強度を高める元素であり、Cおよび/またはMnの一部に替えて添加することができる。Cuの含有量が2.00%を超えると、溶接性が損なわれることから、Cuの含有量は2.00%以下であることが好ましい。Cuの含有量の下限は、特に定めることなく本発明の効果は発揮されるが、Cuによる高強度化の効果を十分に得るには、Cuの含有量は0.01%以上であることが好ましい。
Moは高温での相変態を抑制し、高強度化に有効な元素であり、Cおよび/またはMnの一部に代えて添加してもよい。Moの含有量が1.00%を超えると、熱間での加工性が損なわれ、生産性が低下する。このことから、Moの含有量は1.00%以下であることが好ましい。Moの含有量の下限は、特に定めることなく本発明の効果は発揮されるが、Moによる高強度化の効果を十分に得るには、Moの含有量は0.01%以上であることが好ましい。
Wは高温での相変態を抑制し、高強度化に有効な元素であり、Cおよび/またはMnの一部に代えて添加してもよい。Wの含有量が1.00%を超えると、熱間での加工性が損なわれ、生産性が低下することから、Wの含有量は1.00%以下であることが好ましい。Wの含有量の下限は、特に定めることなく本発明の効果は発揮されるが、Wによる高強度化の効果を十分に得るには、Wの含有量は0.01%以上であることが好ましい。
Vは、析出物強化、フェライト結晶粒の成長抑制による細粒強化および再結晶の抑制を通じた転位強化にて、母材鋼板の強度上昇に寄与する元素である。しかし、Vの含有量が0.150%を超えると、炭窒化物の析出が多くなり成形性が劣化するため、Vの含有量は0.150%以下であることが好ましい。Vの含有量の下限は、特に定めることなく本発明の効果は発揮されるが、Vによる強度上昇効果を十分に得るにはVの含有量は0.005%以上であることが好ましい。
Ca、Ce、Mg、Zr,Hf、REMは、成形性の改善に有効な元素であり、1種又は2種以上を添加することができる。しかし、Ca、Ce、Mg、Zr,Hf、REMの1種または2種以上の含有量の合計が0.5000%を超えると、却って延性を損なう恐れがある。このため、各元素の含有量の合計は0.5000%以下であることが好ましい。Ca、Ce、Mg、Zr,Hf、REMの1種または2種以上の含有量の下限は、特に定めることなく本発明の効果は発揮されるが、母材鋼板の成形性を改善する効果を十分に得るには、各元素の含有量の合計が0.0001%以上であることが好ましい。成形性の観点から、Ca、Ce、Mg、Zr,Hf、REMの1種または2種以上の含有量の合計が0.0005%以上であることがより好ましく、0.0010%以上であることがさら
に好ましい。
本発明の高強度亜鉛めっき鋼板の母材鋼板の組織を規定した理由は以下のとおりである。
「残留オーステナイト:8%以下」
母材鋼板の組織は、母材鋼板の1/8厚~3/8厚の範囲において、残留オーステナイトが体積分率で8%以下に制限されている。
残留オーステナイトは、強度および延性を大きく向上させるが、一方で破壊の起点となって曲げ性を大きく劣化させる。このため、本発明の高強度亜鉛めっき鋼板では、母材鋼板の組織に含まれる残留オーステナイトが、体積分率で8%以下に制限される。高強度亜鉛めっき母材鋼板の曲げ性をさらに高めるには、残留オーステナイトの体積分率を5%以下とすることが好ましい。
なお、母材鋼板の組織全体において、残留オーステナイトが体積分率で8%以下に制限されていることが望ましい。しかしながら、母材鋼板の板厚の1/4を中心とした1/8厚~3/8厚の範囲における金属組織は、母材鋼板全体の組織を代表する。従って、母材鋼板の1/8厚~3/8厚の範囲において、残留オーステナイトが体積分率で8%以下に制限されていれば、実質的に、母材鋼板の組織全体において、残留オーステナイトが体積分率で8%以下に制限されているとみなすことができる。このため、本発明では、母材鋼板の1/8厚~3/8厚の範囲における残留オーステナイトが体積分率の範囲について規定した。
なお同様に、これらフェライト等の金属組織が、母材鋼板の組織全体において所定の範囲であることが望ましい。しかしながら、母材鋼板の板厚の1/4を中心とした1/8厚~3/8厚の範囲における金属組織は、母材鋼板全体の組織を代表する。従って、母材鋼板の1/8厚~3/8厚の範囲において、体積分率で10~75%のフェライトと、合計で10~50%のベイニティックフェライトとベイナイトのいずれか一方もしくは両方と、10~50%の焼戻しマルテンサイトとを含み、フレッシュマルテンサイトが体積分率で15%以下に制限され、パーライトが体積分率で5%以下に制限されていれば、実質的に、母材鋼板の組織全体において、これらフェライト等の金属組織が所定の範囲内であるとみなすことができる。このため、本発明では、母材鋼板の1/8厚~3/8厚の範囲において、これらフェライト等の金属組織の体積分率の範囲を規定した。
フェライトは、延性の向上に有効な組織であり、母材鋼板の組織に体積分率で10~75%含まれていることが好ましい。フェライトの体積分率が10%未満である場合、十分な延性が得られない恐れがある。母材鋼板の組織に含まれるフェライトの体積分率は、延性の観点から15%以上含まれることがより好ましく、20%以上含まれることがさらに好ましい。また、フェライトは軟質な組織であるため、体積分率が75%を超えると十分な強度が得られない場合がある。母材鋼板の引張強度を十分高めるには、母材鋼板の組織に含まれるフェライトの体積分率を65%以下とすることが好ましく、50%以下とすることがさらに好ましい。
パーライトが多くなると、延性が劣化する。このことから、母材鋼板の組織に含まれるパーライトの体積分率は、5%以下に制限されることが好ましい。2%以下であることがより好ましい。
ベイニティックフェライトおよびベイナイトは、強度と延性のバランスに優れた組織であり、母材鋼板の組織に体積分率で合計で10~50%のベイニティックフェライトとベイナイトが含まれていることが好ましい。また、ベイニティックフェライトおよびベイナイトは、軟質なフェライトと硬質なマルテンサイト、焼戻しマルテンサイトおよび残留オーステナイトの中間の強度を有するミクロ組織であり、曲げ性の観点から合計で15%以上含まれることがより好ましく、合計で20%以上含まれることがさらに好ましい。一方、ベイニティックフェライトおよびベイナイトの体積分率が合計で50%を超えると、降伏応力が過度に高まり、形状凍結性が劣化するため好ましくない。なお、ベイニティックフェライトおよびベイナイトは、どちらか一方のみ含有しても良いし、両方を含有しても良い。
フレッシュマルテンサイトは、引張強度を大きく向上させるが、一方で破壊の起点となって曲げ性を大きく劣化させるため、母材鋼板の組織において、体積分率で15%以下に制限されることが好ましい。曲げ性を高めるにはフレッシュマルテンサイトの体積分率を10%以下とすることがより好ましく、5%以下とすることが更に好ましい。
焼戻しマルテンサイトは、引張強度を大きく向上させる組織であり、母材鋼板の組織に体積分率で50%以下含まれていてもよい。引張強度の観点から、焼戻しマルテンサイトの体積分率は10%以上とすることが好ましい。一方、母材鋼板の組織に含まれる焼戻しマルテンサイトの体積分率が50%を超えると、降伏応力が過度に高まり、形状凍結性が劣化することが懸念されるため好ましくない。
本発明の高強度亜鉛めっき鋼板の母材鋼板の組織には、粗大なセメンタイトなど上記以外の組織が含まれていてもよい。しかし、母材鋼板の組織中に粗大なセメンタイトが多くなると、曲げ性が劣化する。このことから、母材鋼板の組織に含まれる粗大なセメンタイトの体積分率は、10%以下であることが好ましく、5%以下であることがより好ましい。
残留オーステナイトの体積分率は、母材鋼板の板面に平行かつ1/4厚の面を観察面としてX線回折を行い、面積分率を算出し、それを持って体積分率と見なすことができる。
上述したように、母材鋼板の板厚の1/4を中心とした1/8厚~3/8厚の範囲における金属組織は、母材鋼板全体の組織を代表するので、母材鋼板の1/4厚における残留オーステナイトの体積分率、および、母材鋼板の1/8厚~3/8厚の範囲におけるフェライト等の金属組織等の金属組織の体積分率を用いて、母材鋼板の組織全体の金属組織を認定することができる。
ベイニティックフェライトは、ラス状の結晶粒の集合であり、ラスの内部に長径20nm以上の鉄系炭化物を含まないものである。
ベイナイトは、ラス状の結晶粒の集合であり、ラスの内部に長径20nm以上の鉄系炭化物を複数有し、さらにそれらの炭化物が単一のバリアント、すなわち同一の方向に伸張した鉄系炭化物群に属するものである。ここで、同一の方向に伸長した鉄系炭化物群とは、鉄系炭化物群の伸長方向の差異が5°以内であるものを意味している。
焼戻しマルテンサイトは、ラス状の結晶粒の集合であり、ラスの内部に長径20nm以上の鉄系炭化物を複数有し、さらにそれらの炭化物が複数のバリアント、すなわち異なる方向に伸長した複数の鉄系炭化物群に属するものである。
なお、FE-SEMを用いてラス状結晶粒内部の鉄系炭化物を観察し、その伸長方向を調べることによって、ベイナイトと焼戻しマルテンサイトは容易に区別しうる。
したがって、フレッシュマルテンサイトの体積分率は、FE-SEMにて観察された腐食されていない領域の面積分率と、X線によって測定した残留オーステナイトの面積分率との差分として求められる。
本発明の高強度亜鉛めっき鋼板は、母材鋼板の所定範囲の硬度分布における尖度K*が-0.30以下である。ここで、本発明の高強度亜鉛めっき鋼板における硬度分布は、次のように定められる。すなわち、母材鋼板の1/8厚~3/8厚の範囲において、直径1μm以下の測定領域を複数設定して、前記複数の測定領域における硬度を測定する。そして、各測定領域の測定値を小さい順に並べて硬度分布を得る。そして、硬度の測定値の全数に0.02を乗じた数であって、該数が小数を含む場合はこれを切り上げて得た整数N0.02を求める。そして、最小硬度の測定値からN0.02番目に大きな測定値の硬度を2%硬度とする。また、硬度の測定値の全数に0.98を乗じた数であって、該数が小数を含む場合はこれを切り下げて得た整数N0.98を求める。そして、最小硬度の測定値からN0.98番目に大きな測定値の硬度を98%硬度とする。そして、本発明の高強度亜鉛めっき鋼板は、前記2%硬度と前記98%硬度の間における硬度分布における尖度K*が、-0.30以下の範囲に定められる。
具体的には、例えば、母材鋼板の1/8厚~3/8厚の範囲において、直径1μm以下の測定領域を1000箇所設定し、それら1000箇所に測定領域における硬度を測定した場合、「硬度の測定値の全数」は、1000である。そして、それら1000箇所の各測定領域で測定された硬度の測定値を小さい順に並べることにより、硬度分布が得られる。
この場合、硬度の測定値の全数(すなわち1000)に0.02を乗じた数(=20)が、「整数N0.02」となる。そして、上記求めた硬度分布において、最小硬度の測定値からN0.02番目(すなわち20番目)に大きな測定値の硬度が2%硬度となる。
また同様に、硬度の測定値の全数(すなわち1000)に0.98を乗じた数(=980)が、「整数N0.98」となる。そして、上記求めた硬度分布において、最小硬度の測定値からN0.98番目(すなわち980番目)に大きな測定値の硬度が98%硬度となる。
なお、硬度の測定値の全数が1000である場合について説明したが、硬度の測定値の全数が2000(すなわち、2000箇所で硬度を測定した場合)であれば、「整数N0.02」は40となり、「整数N0.98」は1960となる。そして、最小硬度の測定値から40番目に大きな測定値の硬度が2%硬度となり、1960番目に大きな測定値の硬度が98%硬度となる。
また、上述の手順によって「整数N0.02」を求める場合、0.02を乗じた数が小数を含む場合は、小数点以下を切り上げて得た整数が、「整数N0.02」となる。同様に、「整数N0.98」を求める場合、0.98を乗じた数が小数を含む場合は、小数点以下を切り上げて得た整数が、「整数N0.98」となる。
また、本発明の高強度亜鉛めっき鋼板は、母材鋼板の表層のビッカース硬さと、母材鋼板の1/4厚のビッカース硬さの比「(表層のビッカース硬さ)/(1/4厚のビッカース硬さ)」が0.35~0.70である。なお、本発明において「母材鋼板の表層のビッカース硬さ」とは、母材鋼板の表面と合金化亜鉛めっき層との界面から母材鋼板側へ10μm入った箇所のビッカース硬さを意味する。
本発明の高強度亜鉛めっき鋼板は、母材鋼板の表面に合金化亜鉛めっき層が形成されている。合金化亜鉛めっき層は、合金化反応によって亜鉛めっき中に鋼中のFeが拡散してできたFe-Zn合金を主体としており、合金化亜鉛めっき層中の鉄の含有量が質量%で8~12%である。本発明においては、合金化亜鉛めっき層中の鉄の含有量が8~12%であるので、高強度亜鉛めっき鋼板に曲げ加工を行った場合における合金化亜鉛めっき層の破壊・剥離を充分に防止できる。合金化亜鉛めっき層の鉄の含有量は、良好な耐フレーキング性を確保するために8.0%以上とされており、9.0%以上であることが好ましい。また、合金化亜鉛めっき層中の鉄の含有量は、良好な耐パウダリング性を確保するために12.0%以下とされており、11.0%以下であることが好ましい。また、合金化亜鉛めっき層には、不純物としてAlが含まれても良い。
次に、本発明の高強度亜鉛めっき鋼板を製造する方法について詳細に説明する。
本発明の高強度亜鉛めっき鋼板を製造するには、最初に母材鋼板となる鋼板を製造する。鋼板を製造するには、まず、上述した化学成分(組成)を有するスラブを鋳造する。そして、1050℃以上に加熱し、880℃以上の仕上げ熱延温度で熱間圧延を完了し、750℃以下の温度域にて巻き取る熱間圧延工程を行う。
熱間圧延工程に供するスラブは、連続鋳造スラブや薄スラブキャスターなどで製造したものを用いることができる。本発明の高強度亜鉛めっき鋼板の製造方法は、鋳造後に直ちに熱間圧延を行う連続鋳造-直接圧延(CC-DR)のようなプロセスに適合する。
Ar3=901-325×C+33×Si-92×(Mn+Ni/2+Cr/2+Cu/2+Mo/2)+52×Al
上記式において、C、Si、Mn、Ni、Cr、Cu、Mo、Alは各元素の含有量[質量%]である。元素を含有していない場合は、0として計算する。
一方、仕上げ熱延温度の上限は特に定めることなく、本発明の効果は発揮されるが、仕上げ熱延温度を過度に高温とした場合、その温度を確保するためにスラブ加熱温度を過度に高温にしなければならない。このことから、仕上げ熱延温度の上限温度は、1000℃以下とすることが望ましい。
一方、巻き取り温度が500℃未満となると熱延鋼板の強度が過度に高まり、冷間圧延が困難となるため、巻き取り温度は500℃以上とする。冷間圧延の負荷を軽減するため、巻き取り温度は550℃以上とすることが好ましく、600℃以上とすることがより好ましい。
酸洗後の熱延鋼板は、そのまま連続焼鈍工程に供しても構わないが、酸洗した熱延鋼板に対して板厚の調整や形状矯正を目的として冷間圧延工程を行ってもよい。冷間圧延工程を行う場合、板厚精度が高く優れた形状を有する母材鋼板を得るために、圧下率を30~75%の範囲とすることが好ましい。圧下率が30%未満であると、形状を平坦に保つことが困難であり、最終製品の延性が劣悪となる恐れがある。冷間圧延工程における圧下率は40%以上であることが好ましく、45%以上であることがより好ましい。一方、圧下率が75%を超える冷延では、冷延荷重が大きくなりすぎて冷延が困難となる。このことから、圧下率は75%以下であることが好ましい。冷延荷重の観点から、圧下率は70%以下であることがより好ましい。
次に、熱間圧延工程後に得られた熱延鋼板、もしくは、冷間圧延工程後に得られた冷延鋼板を、連続焼鈍ラインに通板させる、連続焼鈍工程が行われる。本発明の連続焼鈍工程では、600℃~Ac1変態点間の温度範囲を1℃/秒以上の平均加熱速度で鋼板が加熱される。そして、(Ac1変態点+40)~Ac3変態点間の焼鈍温度で、かつ、log(水分圧/水素分圧)が-3.0~0.0の雰囲気で、20秒~600秒、鋼板が滞留されるとともに、半径800mm以下のロールを用いて2回以上の曲げ-曲げ戻し変形加工が鋼板に加えられ、表裏面の累積歪量の差を0.0050以下とする処理が行われる。その後、740℃~650℃の温度範囲を1.0~5.0℃/秒の平均冷却速度で鋼板が冷却される。
連続焼鈍工程においては、まず、熱間圧延工程後に得られた熱延鋼板、もしくは、冷間圧延工程後に得られた冷延鋼板が、600℃~Ac1変態点間の温度範囲を1℃/秒以上の平均加熱速度で加熱される。鋼板の温度が600℃以上になると、鋼板からの脱炭が開始される。600℃~Ac1変態点間の温度範囲では、鋼板に含まれる鉄は、内部も表面も同じbcc鉄である。本発明において、bcc鉄とは、体心立方格子を持ったフェライト、ベイナイト、ベイニティックフェライト、マルテンサイトの総称である。
曲げ-曲げ戻し変形加工において用いるロールは、半径800mm以下である。ロールの半径を800mm以下とすることで、鋼板の表層に容易に歪を導入できる。ロールの半径が800mmを超えると、鋼板の表面に充分に歪を導入できず、表層がbcc鉄に変態されないために、表層の硬度が充分に低くならない。
650℃~500℃の温度範囲での平均冷却速度が5℃/秒未満であると、パーライトおよび/または鉄系炭化物が多量に生成するため、残留オーステナイトが不十分となる。この観点から、平均冷却速度は7.0℃/秒以上であることが好ましく、8.0℃/秒以上であることがより好ましい。一方、650℃~500℃の温度範囲での平均冷却速度の上限は特に定めることなく本発明の効果は発揮されるが、平均冷却速度が200℃/秒を超えるには特殊な設備が必要となり、コストの観点から冷却速度の上限を200℃/秒とする。
次に、連続焼鈍工程後の鋼板を亜鉛めっき浴に浸漬してから470~650℃の温度で10~120秒滞留する合金化処理を行う。これにより、母材鋼板の表面にZn-Fe合金を含み、鉄の含有量が8~12%である合金化亜鉛めっき層が形成された本発明の高強度亜鉛めっき鋼板が形成される。
なお、通常、母材鋼板の炭素含有量が多いほど、合金化亜鉛めっき層に含まれる鉄の含有量が低いものになるとともに、母材鋼板と合金化亜鉛めっき層との密着性が低いものとなる。また、本発明においては、引張最大強度900MPa以上の高強度亜鉛めっき鋼板とするために、強度を向上させる元素である炭素を多く含有させている。しかし、本発明においては、連続焼鈍工程後に得られた母材鋼板となる冷延鋼板の表層の炭素濃度が低いため、めっき合金化工程において、鉄の含有量が8~12%である密着性に優れた合金化亜鉛めっき層が形成される。
また、合金化処理の温度は、480~560℃であることが好ましく、合金化処理の滞留時間は、15~60秒であることが好ましい。
例えば、本発明においては、上述した方法により得られた亜鉛めっき鋼板の合金化亜鉛めっき層の表面に、P酸化物および/またはPを含む複合酸化物からなる皮膜を付与しても構わない。
リン酸化物および/またはリンを含む複合酸化物からなる皮膜は、鋼板を加工する際に潤滑剤として機能させることができ、母材鋼板の表面に形成した合金化亜鉛めっき層を保護することができる。
表1および表2に示すA~Z、AA~AC、表3に示すBA~BFの化学成分(組成)を有するスラブを鋳造し、鋳造後直ちに表4~表7に示す条件(スラブ加熱温度、仕上げ熱延温度)で熱間圧延し、冷却し、表4~表7に示す温度で巻き取り、酸洗を施した。実験例4、10、16、22、49、54、102、106は熱間圧延そのまま(冷間圧延なし)、他の実験例は表3~表5に示す条件(圧下率)の冷間圧延を施した。そして、各実験例1~109、201~218の鋼板について、表8~表11に示す条件で連続焼鈍工程とめっき合金化工程を施した。
焼鈍においては、600℃~Ac1変態点間の温度範囲を表8~表11に記載の平均加熱速度で通過し、表8~表118に記載の最高加熱温度(焼鈍温度)まで加熱し、水分圧と水素分圧(log(PH2O/PH2)を表8~表11に記載の条件で制御した窒素を主体とする雰囲気で、表8~表11に記載の滞留時間(連続焼鈍工程の滞留時間)で滞留させる脱炭処理を行った。
一方、実験例201~218では、表11に示す曲げ曲げ戻し変形加工回数で複数回(2~12回)の曲げ-曲げ戻し変形加工を行った。また、実験例201~218では、曲げ-曲げ戻し変形加工を行うロールの半径を変化させた。実験例201~218について行った各曲げ-曲げ戻し変形加工に用いたロールの最小ロール半径(mm)、平均ロール半径(mm)を表11に示す。また、曲げ-曲げ戻し変形加工において、鋼板の表面および裏面のそれぞれに導入された総ひずみ量のうち、大きい方のひずみ量を最大合計ひずみとして示した。また、実験例201~218では、鋼板の板厚を0.70~8.00mmに変化させた。
表8~表11に記載の△εは、曲げ-曲げ戻し変形加工を行ったことにより導入される歪量を、鋼板の表裏面それぞれについて計算し、その差の絶対値を示したものである。
合金化処理後、200~350℃の温度範囲で表8~表11に記載の滞留時間(合金化処理の滞留時間)で滞留させた。
その後、実験例9および49では亜鉛めっき鋼板の表層にPを含む複合酸化物からなる皮膜を付与した。
また、EDXを用いて、合金化亜鉛めっき層の1/2厚さにおける鉄の含有量を測定した。その結果を、表12~表15に示す。
母材鋼板の表層および1/4厚における硬さは、圧延方向に互いに1mm以上離れた5ヶ所においてビッカース硬さを測定し、最大値と最小値を破棄し、残り3点の平均値とした。ビッカース硬さの測定では、荷重を100gfとした。なお、表層のビッカース硬さは、合金化亜鉛めっき層と母材鋼板との界面から母材鋼板側へ40μm入った線上において測定した。
硬度分布の尖度K*は、ベルコビッチタイプの三角すい圧子を備えたダイナミック微小硬度計を用いて、押込み深さ測定法にて、押込み荷重1g重で硬度を測定した結果を用いて算出した。なお、硬度の測定位置は、鋼板の板面に垂直で、かつ、圧延方向(圧下方向)に平行な板厚断面における板厚の1/4を中心として1/8厚~3/8厚の範囲とした。また、硬度の測定値の全数は1000とした。
実験例1~109、201~218の鋼板からJIS Z 2201に準拠した引張試験片を採取し、引張試験をJIS Z 2241に準拠して行い、降伏応力「YS」、引張強度「TS」、全伸び「EL」を測定した。
また、フランジ性を評価する穴広げ試験(JFST1001)を行い、伸びフランジ性の指標である穴広げ限界値「λ」を算出した。
また、90度V曲げ試験を行った。実験例1~109の鋼板から35mm×100mmの試験片を切り出し、シャー切断面を機械研削し、曲げ半径を板厚の2倍として評価した。そして所定の形状となったものを合格(○)、所定の形状にならなかったものを不合格(×)とした。また、曲げ試験時には割れ、ネッキングおよびめっき剥離の有無を目視にて個別に評価し、それらが完全に無いものを合格(○)、あるものを不合格(×)とした。
これに対し、実験例1~109、201~218のうち比較例である実験例は、引張強度が900MPa未満であるか、曲げ試験の結果に×が含まれており、高強度と曲げ性の両方に優れることを満足しなかった。
実験例108はSiの添加量が少なく、軟質組織の固溶強化が不十分であり、鋼板の表層硬さが内部と比べて大きく軟化するため、伸びフランジ性および強度が劣位である。
実験例109はMnの添加量が少なく、破壊の起点となる残留オーステナイトの体積分率が大きいため、伸びフランジ性および曲げ性が劣位である。
実験例98は熱間圧延後にコイルへ巻取る温度が高い例であり、ミクロ組織が非常に粗大なものとなるため、延性、伸びフランジ性および曲げ性が劣位である。
実験例6は焼鈍工程における加熱速度が遅い例であり、鋼板の脱炭が進み、表層の硬さが大きく低下したため、伸びフランジ性および曲げ性が劣位である。
一方、実験例12は焼鈍工程における最高加熱温度が高い例であり、破壊の起点となる残留オーステナイトの体積分率が大きいため、伸びフランジ性および曲げ性が劣位である。
一方、実験例18は脱炭処理温度域における滞留時間が長い例であり、表層の硬さが過度に低下したため、伸びフランジ性および曲げ性が劣位である。
一方、実験例24は脱炭処理温度域における雰囲気中の水蒸気分圧が低い例であり、表層の硬さが過度に高いため、曲げ性が劣位である。
実験例33は740℃~650℃の平均冷却速度が低い例であり、鋼板内部の硬さ分布における尖度が大きいため、伸びフランジ性および曲げ性が劣位である。
一方、実験例34は740℃~650℃の平均冷却速度が高い例であり、鋼板内部の硬さ分布における尖度が大きいため、延性および曲げ性が劣位である。
実験例38はめっき層の合金化処理温度が高い例であり、めっき層中のFe%が過剰であり、また、鋼板内部に破壊の起点となる粗大な鉄系炭化物が生成したため、延性、伸びフランジ性および曲げ性が劣位である。
一方、実験例39はめっき層の合金化処理温度が低い例であり、めっき層中のFe%が不足し、曲げ性が劣位である。
一方、実験例44はめっき層の合金化処理時間が長い例であり、鋼板内部に破壊の起点となる粗大な鉄系炭化物が生成したため、延性、伸びフランジ性および曲げ性が劣位である。
実験例203は鋼板の板厚が著しく薄く、鋼板の平坦度が保てず、所定の特性評価試験を行えなかった。
実験例206は表面および裏面のそれぞれに導入された総ひずみ量の差、Δεが大きい例であり、曲げ性が劣位である。
実験例209および218は1回の曲げ加工によって導入されるひずみ量が小さく、表層の硬さが過度に硬いため、曲げ性が劣位である。
実験例212および215は1回の曲げ加工によって導入されるひずみ量が大きく、鋼板の形状が損なわれ、十分な平坦度が得られず、所定の特性評価試験を行えなかった。
Claims (11)
- 質量%で、
C:0.075~0.300%、
Si:0.30~2.50%、
Mn:1.30~3.50%、
P:0.001~0.050%、
S:0.0001~0.0100%、
Al:0.005~1.500%、
N:0.0001~0.0100%、
O:0.0001~0.0100%、
を含有し、残部が鉄および不可避的不純物からなる母材鋼板の表面に、合金化亜鉛めっき層が形成されてなる引張最大強度900MPa以上の高強度亜鉛めっき鋼板であり、
前記母材鋼板の1/8厚~3/8厚の範囲において、残留オーステナイトが体積分率で8%以下に制限され、
前記母材鋼板の1/8厚~3/8厚の範囲において、直径1μm以下の測定領域を複数設定して、前記複数の測定領域における硬度の測定値を小さい順に並べて硬度分布を得るとともに、硬度の測定値の全数に0.02を乗じた数であって該数が小数を含む場合はこれを切り上げて得た整数N0.02を求め、最小硬度の測定値からN0.02番目に大きな測定値の硬度を2%硬度とし、また、硬度の測定値の全数に0.98を乗じた数であって該数が小数を含む場合はこれを切り下げて得た整数N0.98を求め、最小硬度の測定値からN0.98番目に大きな測定値の硬度を98%硬度としたとき、前記2%硬度と前記98%硬度の間における前記硬度分布の尖度K*が-0.30以下であり、
前記母材鋼板の表層のビッカース硬さと、前記母材鋼板の1/4厚のビッカース硬さの比が0.35~0.70であり、
前記合金化亜鉛めっき層の鉄の含有量が、質量%で8~12%である、曲げ性に優れた高強度亜鉛めっき鋼板。 - 前記母材鋼板の組織が、前記母材鋼板の1/8厚~3/8厚の範囲において、体積分率で10~75%のフェライトと、合計で10~50%のベイニティックフェライトとベイナイトのいずれか一方もしくは両方と、10~50%の焼戻しマルテンサイトとを含み、フレッシュマルテンサイトが体積分率で15%以下に制限され、パーライトが体積分率で5%以下に制限された、請求項1に記載の曲げ性に優れた高強度亜鉛めっき鋼板。
- 前記母材鋼板がさらに、質量%で、
Ti:0.005~0.150%、
Nb:0.005~0.150%の1種または2種を含有する、請求項1に記載の曲げ性に優れた高強度亜鉛めっき鋼板。 - 前記母材鋼板がさらに、質量%で、
B:0.0001~0.0100%、
Cr:0.01~2.00%、
Ni:0.01~2.00%、
Cu:0.01~2.00%、
Mo:0.01~1.00%、
W:0.01~1.00%の1種または2種以上を含有する、請求項1に記載の曲げ性に優れた高強度亜鉛めっき鋼板。 - 前記母材鋼板がさらに、質量%で、
V:0.005~0.150%含有する、請求項1に記載の曲げ性に優れた高強度亜鉛めっき鋼板。 - 前記母材鋼板がさらに、
Ca、Ce、Mg、Zr,Hf、REMの1種または2種以上を合計で0.0001~0.5000質量%含有する、請求項1に記載の曲げ性に優れた高強度亜鉛めっき鋼板。 - 前記合金化亜鉛めっき層の表面に、リン酸化物からなる皮膜とリンを含む複合酸化物からなる皮膜のいずれか一方もしくは両方が形成されている、請求項1に記載の曲げ性に優れた高強度亜鉛めっき鋼板。
- 質量%で、
C:0.075~0.300%、
Si:0.30~2.50%、
Mn:1.30~3.50%、
P:0.001~0.050%、
S:0.0001~0.0100%、
Al:0.005~1.500%、
N:0.0001~0.0100%、
O:0.0001~0.0100%、
を含有し、残部が鉄および不可避的不純物からなるスラブを1050℃以上に加熱し、880℃以上の仕上げ熱延温度で熱間圧延を完了し、750℃以下の温度域にて巻き取る熱間圧延工程と、
鋼板を、600℃~Ac1変態点間の温度範囲を1℃/秒以上の平均加熱速度で加熱し、(Ac1変態点+40)℃~Ac3変態点間の焼鈍温度で、かつlog(水分圧/水素分圧)が-3.0~0.0の雰囲気で20秒~600秒滞留するとともに、半径800mm以下のロールを用いて2回以上の曲げ-曲げ戻し変形加工を行い、表裏面の累積歪量の差を0.0050以下とした後、740℃~650℃の温度範囲を1.0~5.0℃/秒の平均冷却速度で冷却し、650℃~500℃の温度範囲を5~200℃/秒の平均冷却速度で冷却する連続焼鈍工程と、
連続焼鈍工程後の鋼板を亜鉛めっき浴に浸漬してから470~650℃の温度で10~120秒滞留する合金化処理を行うめっき合金化工程と、
を備える、曲げ性に優れた高強度亜鉛めっき鋼板の製造方法。 - 前記熱間圧延工程後、前記連続焼鈍工程の前に、30~75%の圧下率で冷延する冷間圧延工程を行う、請求項8に記載の曲げ性に優れた高強度亜鉛めっき鋼板の製造方法。
- 前記合金化処理工程後に、200~350℃の温度で30~1000秒滞留する、請求項8に記載の曲げ性に優れた高強度亜鉛めっき鋼板の製造方法。
- 前記合金化処理工程後に、リン酸化物および/またはリンを含む複合酸化物からなる皮膜を付与する工程を行う、請求項8に記載の耐衝撃特性に優れた高強度亜鉛めっき鋼板の製造方法。
Priority Applications (11)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA2842897A CA2842897C (en) | 2011-07-29 | 2012-07-27 | High-strength galvanized steel sheet excellent in bendability and manufacturing method thereof |
MX2014000882A MX360332B (es) | 2011-07-29 | 2012-07-27 | Lamina de acero galvanizado de alta resistencia, excelente en su capacidad de combado y metodo de fabricacion de la misma. |
ES12820441T ES2727865T3 (es) | 2011-07-29 | 2012-07-27 | Lámina de acero galvanizado de alta resistencia excelente en cuanto a su capacidad de flexión y método de fabricación de la misma |
JP2013501959A JP5273324B1 (ja) | 2011-07-29 | 2012-07-27 | 曲げ性に優れた高強度亜鉛めっき鋼板およびその製造方法 |
EP12820441.9A EP2738280B1 (en) | 2011-07-29 | 2012-07-27 | High-strength galvanized steel sheet having superior bendability and method for producing same |
US14/234,826 US9234268B2 (en) | 2011-07-29 | 2012-07-27 | High-strength galvanized steel sheet excellent in bendability and manufacturing method thereof |
PL12820441T PL2738280T3 (pl) | 2011-07-29 | 2012-07-27 | Blacha stalowa cienka ocynkowana o dużej wytrzymałości mająca doskonałą zginalność oraz sposób jej wytwarzania |
BR112014001994A BR112014001994A2 (pt) | 2011-07-29 | 2012-07-27 | folha de aço galvanizado de alta resistência excelente em flexibilidade e método de fabricação da mesma |
CN201280037618.4A CN103717773B (zh) | 2011-07-29 | 2012-07-27 | 弯曲性优异的高强度镀锌钢板及其制造方法 |
KR1020147003572A KR101597473B1 (ko) | 2011-07-29 | 2012-07-27 | 굽힘성이 우수한 고강도 아연 도금 강판 및 그 제조 방법 |
RU2014106991/02A RU2569615C2 (ru) | 2011-07-29 | 2012-07-27 | Высокопрочный гальванизированный стальной лист, имеющий превосходную изгибаемость, и способ его производства |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2011167436 | 2011-07-29 | ||
JP2011-167436 | 2011-07-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2013018739A1 true WO2013018739A1 (ja) | 2013-02-07 |
Family
ID=47629262
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2012/069260 WO2013018739A1 (ja) | 2011-07-29 | 2012-07-27 | 曲げ性に優れた高強度亜鉛めっき鋼板およびその製造方法 |
Country Status (13)
Country | Link |
---|---|
US (1) | US9234268B2 (ja) |
EP (1) | EP2738280B1 (ja) |
JP (1) | JP5273324B1 (ja) |
KR (1) | KR101597473B1 (ja) |
CN (1) | CN103717773B (ja) |
BR (1) | BR112014001994A2 (ja) |
CA (1) | CA2842897C (ja) |
ES (1) | ES2727865T3 (ja) |
MX (1) | MX360332B (ja) |
PL (1) | PL2738280T3 (ja) |
RU (1) | RU2569615C2 (ja) |
TW (1) | TWI493055B (ja) |
WO (1) | WO2013018739A1 (ja) |
Cited By (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2013181225A (ja) * | 2012-03-02 | 2013-09-12 | Jfe Steel Corp | 高強度溶融亜鉛めっき鋼板及びその製造方法 |
WO2014010415A1 (ja) * | 2012-07-12 | 2014-01-16 | 株式会社神戸製鋼所 | 降伏強度と成形性に優れた高強度溶融亜鉛めっき鋼板およびその製造方法 |
JP2015113475A (ja) * | 2013-12-09 | 2015-06-22 | Jfeスチール株式会社 | 高強度冷延鋼板およびその製造方法 |
JP2015528058A (ja) * | 2012-07-10 | 2015-09-24 | ティッセンクルップ スチール ヨーロッパ アクチェンゲゼルシャフトThyssenKrupp Steel Europe AG | 冷間圧延鋼板製品およびその製造方法 |
WO2016072477A1 (ja) * | 2014-11-05 | 2016-05-12 | 新日鐵住金株式会社 | 溶融亜鉛めっき鋼板 |
WO2016072479A1 (ja) * | 2014-11-05 | 2016-05-12 | 新日鐵住金株式会社 | 溶融亜鉛めっき鋼板 |
US20160168656A1 (en) * | 2012-10-18 | 2016-06-16 | JFE Steel Coporation | High-strength cold-rolled steel sheet and method for producing the same |
JP2016216808A (ja) * | 2015-05-26 | 2016-12-22 | 新日鐵住金株式会社 | 成形性に優れた高強度鋼板及びその製造方法 |
JP2017057460A (ja) * | 2015-09-16 | 2017-03-23 | 新日鐵住金株式会社 | 高強度合金化溶融亜鉛めっき鋼板と該鋼板用熱延鋼板及びそれらの製造方法 |
JP2017509789A (ja) * | 2014-12-19 | 2017-04-06 | ポスコPosco | 穴広げ性に優れた溶融亜鉛めっき鋼板、合金化溶融亜鉛めっき鋼板及びその製造方法 |
WO2017145322A1 (ja) * | 2016-02-25 | 2017-08-31 | 新日鐵住金株式会社 | 鋼板の製造方法及び鋼板の連続焼鈍装置 |
KR20170137899A (ko) | 2015-05-29 | 2017-12-13 | 제이에프이 스틸 가부시키가이샤 | 고강도 냉연 강판, 고강도 도금 강판 및 이것들의 제조 방법 |
WO2018062342A1 (ja) * | 2016-09-30 | 2018-04-05 | Jfeスチール株式会社 | 高強度めっき鋼板及びその製造方法 |
WO2018159405A1 (ja) * | 2017-02-28 | 2018-09-07 | Jfeスチール株式会社 | 高強度鋼板およびその製造方法 |
WO2019167933A1 (ja) * | 2018-02-28 | 2019-09-06 | Jfeスチール株式会社 | 冷延鋼板及びその製造方法 |
US10501832B2 (en) * | 2015-04-22 | 2019-12-10 | Nippon Steel Corporation | Plated steel sheet |
WO2020158065A1 (ja) * | 2019-01-30 | 2020-08-06 | Jfeスチール株式会社 | 高強度鋼板およびその製造方法 |
US10822683B2 (en) | 2014-11-05 | 2020-11-03 | Nippon Steel Corporation | Hot-dip galvanized steel sheet |
US10927429B2 (en) | 2015-12-15 | 2021-02-23 | Tata Steel Ijmuiden B.V. | High strength hot dip galvanised steel strip |
US12139771B2 (en) | 2019-01-30 | 2024-11-12 | Jfe Steel Corporation | High-strength steel sheet and method for producing the same |
Families Citing this family (51)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA2809171C (en) | 2009-01-30 | 2017-12-19 | Jfe Steel Corporation | Thick-walled high-strength hot rolled steel sheet having excellent hydrogen induced cracking resistance |
TWI468534B (zh) * | 2012-02-08 | 2015-01-11 | Nippon Steel & Sumitomo Metal Corp | 高強度冷軋鋼板及其製造方法 |
CN105899699B (zh) | 2014-01-06 | 2017-07-28 | 新日铁住金株式会社 | 钢材及其制造方法 |
CN104018088B (zh) * | 2014-05-12 | 2016-05-11 | 盐城市鑫洋电热材料有限公司 | 一种高强热镀锌钢板及其制备方法 |
JP6319443B2 (ja) | 2014-07-18 | 2018-05-09 | 新日鐵住金株式会社 | 鋼材およびその製造方法 |
JP6085348B2 (ja) * | 2015-01-09 | 2017-02-22 | 株式会社神戸製鋼所 | 高強度めっき鋼板、並びにその製造方法 |
JP6010144B2 (ja) * | 2015-01-09 | 2016-10-19 | 株式会社神戸製鋼所 | めっき性、加工性、および耐遅れ破壊特性に優れた高強度めっき鋼板、並びにその製造方法 |
CN104711481B (zh) * | 2015-03-20 | 2017-03-15 | 苏州纽东精密制造科技有限公司 | 一种货架承重高强度钢及其热处理工艺 |
JP7059010B2 (ja) * | 2015-04-10 | 2022-04-25 | ザ・ナノスティール・カンパニー・インコーポレーテッド | 金属合金における端部形成能の改善 |
US10308996B2 (en) * | 2015-07-30 | 2019-06-04 | Hyundai Motor Company | Hot stamping steel and producing method thereof |
KR102148739B1 (ko) | 2016-01-29 | 2020-08-27 | 제이에프이 스틸 가부시키가이샤 | 고강도 아연 도금 강판, 고강도 부재 및 고강도 아연 도금 강판의 제조 방법 |
PL3378965T3 (pl) * | 2016-02-25 | 2021-01-25 | Nippon Steel Corporation | Blacha stalowa cienka o dużej wytrzymałości cynkowana zanurzeniowo na gorąco o doskonałej odporności na łuszczenie przy uderzeniu oraz odporności na korozję obszaru poddawanego obróbce |
US11560606B2 (en) | 2016-05-10 | 2023-01-24 | United States Steel Corporation | Methods of producing continuously cast hot rolled high strength steel sheet products |
AU2017263399B2 (en) | 2016-05-10 | 2022-03-24 | United States Steel Corporation | High strength steel products and annealing processes for making the same |
US11993823B2 (en) | 2016-05-10 | 2024-05-28 | United States Steel Corporation | High strength annealed steel products and annealing processes for making the same |
KR101758567B1 (ko) * | 2016-06-23 | 2017-07-17 | 주식회사 포스코 | 강도 및 성형성이 우수한 클래드 강판 및 그 제조방법 |
KR101967959B1 (ko) | 2016-12-19 | 2019-04-10 | 주식회사 포스코 | 굽힘 가공성이 우수한 초고강도 강판 및 이의 제조방법 |
CN110100030B (zh) * | 2016-12-23 | 2021-04-20 | Posco公司 | 弯曲加工性优异的超高强度热轧钢板及其制造方法 |
JP6439900B2 (ja) * | 2016-12-27 | 2018-12-19 | Jfeスチール株式会社 | 高強度亜鉛めっき鋼板及びその製造方法 |
TWI616540B (zh) * | 2017-01-26 | 2018-03-01 | Nippon Steel & Sumitomo Metal Corp | Steel plate |
TWI627290B (zh) * | 2017-02-02 | 2018-06-21 | Nippon Steel & Sumitomo Metal Corp | Steel plate |
US11408046B2 (en) * | 2017-02-20 | 2022-08-09 | Nippon Steel Corporation | High strength steel sheet |
KR102228292B1 (ko) * | 2017-02-20 | 2021-03-16 | 닛폰세이테츠 가부시키가이샤 | 강판 |
WO2018179386A1 (ja) * | 2017-03-31 | 2018-10-04 | 新日鐵住金株式会社 | 冷間圧延鋼板および溶融亜鉛めっき冷間圧延鋼板 |
WO2018203097A1 (en) | 2017-05-05 | 2018-11-08 | Arcelormittal | A method for the manufacturing of liquid metal embrittlement resistant galvannealed steel sheet |
CA3079796A1 (en) * | 2017-11-15 | 2019-05-23 | Nippon Steel Corporation | High-strength cold-rolled steel sheet |
WO2019116531A1 (ja) | 2017-12-15 | 2019-06-20 | 日本製鉄株式会社 | 鋼板、溶融亜鉛めっき鋼板および合金化溶融亜鉛めっき鋼板 |
US11913118B2 (en) | 2018-03-01 | 2024-02-27 | Nucor Corporation | Zinc alloy coated press-hardenable steels and method of manufacturing the same |
CN108441763B (zh) * | 2018-03-23 | 2019-11-19 | 马钢(集团)控股有限公司 | 一种抗拉强度1000MPa级冷轧热浸镀锌高强钢及其制备方法 |
TWI671410B (zh) * | 2018-03-30 | 2019-09-11 | 日商日本製鐵股份有限公司 | 鋼板及其製造方法 |
US11118252B2 (en) * | 2018-03-30 | 2021-09-14 | Nippon Steel Corporation | Galvannealed steel sheet |
CN108677087B (zh) * | 2018-05-22 | 2020-10-27 | 攀钢集团攀枝花钢铁研究院有限公司 | 低合金高强冷轧退火钢板和合金镀层钢板的制备方法 |
JP7430345B2 (ja) * | 2018-09-04 | 2024-02-13 | 国立大学法人東北大学 | 鉄基合金および鉄基合金の製造方法 |
EP3904565A4 (en) * | 2018-12-27 | 2022-09-07 | Nippon Steel Corporation | NI-PLATED STEEL SHEET WITH EXCELLENT CORROSION RESISTANCE POST-TREATMENT AND ITS PRODUCTION PROCESS |
MX2021008065A (es) * | 2019-01-07 | 2021-08-05 | Nippon Steel Corp | Lamina de acero y metodo para fabricar la misma. |
CN113260721B (zh) * | 2019-01-07 | 2023-05-12 | 日本制铁株式会社 | 钢板及其制造方法 |
CN113227456B (zh) | 2019-03-29 | 2024-03-22 | 日本制铁株式会社 | 被覆钢构件、被覆钢板及它们的制造方法 |
CN113597473B (zh) * | 2019-04-11 | 2022-11-01 | 日本制铁株式会社 | 钢板及其制造方法 |
US20220220577A1 (en) * | 2019-05-16 | 2022-07-14 | Jfe Steel Corporation | High strength member, method for manufacturing high strength member, and method for manufacturing steel sheet for high strength member |
MX2022006955A (es) * | 2019-12-19 | 2022-07-12 | Nippon Steel Corp | Lamina de acero y metodo de fabricacion de la misma. |
US12031215B2 (en) | 2020-01-29 | 2024-07-09 | Nucor Corporation | Zinc alloy coating layer of press-hardenable steel |
CN111378904B (zh) * | 2020-05-14 | 2021-03-26 | 太仓鑫祥金属制品有限公司 | 一种耐腐蚀超高强度折弯机用钢部件的制备工艺 |
US12091723B2 (en) | 2020-06-30 | 2024-09-17 | Jfe Steel Corporation | Galvanized steel sheet, member, and method for producing them |
KR102464387B1 (ko) * | 2020-10-26 | 2022-11-07 | 현대제철 주식회사 | 고강도 합금화 용융아연도금 강판 및 그 제조방법 |
KR102490312B1 (ko) * | 2020-12-09 | 2023-01-19 | 주식회사 포스코 | 연성 및 성형성이 우수한 고강도 용융아연도금강판 |
KR20220084651A (ko) * | 2020-12-14 | 2022-06-21 | 주식회사 포스코 | 굽힘성 및 성형성이 우수한 고강도 강판 및 이의 제조방법 |
KR102438474B1 (ko) | 2020-12-21 | 2022-09-01 | 주식회사 포스코 | 무방향성 전기강판 및 그 제조방법 |
MX2023008837A (es) * | 2021-02-10 | 2023-08-11 | Jfe Steel Corp | Lamina de acero de alta resistencia y metodo para fabricacion de la misma. |
KR20230094376A (ko) * | 2021-12-21 | 2023-06-28 | 주식회사 포스코 | 점용접성이 우수한 고강도 고성형성 강판 및 그 제조방법 |
WO2023118350A1 (en) * | 2021-12-24 | 2023-06-29 | Tata Steel Nederland Technology B.V. | High strength steel strip or sheet excellent in ductility and bendability, manufacturing method thereof, car or truck component |
CN119220893A (zh) * | 2023-06-30 | 2024-12-31 | 宝山钢铁股份有限公司 | 一种高r值的超高强钢板及其制造方法 |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007009317A (ja) * | 2005-05-31 | 2007-01-18 | Jfe Steel Kk | 伸びフランジ成形性に優れた高強度冷延鋼板および溶融亜鉛めっき鋼板とそれらの製造方法 |
JP2009228128A (ja) * | 2008-02-29 | 2009-10-08 | Jfe Steel Corp | 冷延鋼板およびその製造方法 |
JP2010150580A (ja) * | 2008-12-24 | 2010-07-08 | Jfe Steel Corp | 鋼板及びその製造方法 |
JP2011111675A (ja) * | 2009-11-30 | 2011-06-09 | Nippon Steel Corp | 耐水素脆化特性に優れた引張最大強度900MPa以上の高強度鋼板および高強度冷延鋼板の製造方法、高強度亜鉛めっき鋼板の製造方法 |
Family Cites Families (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05195149A (ja) | 1992-01-21 | 1993-08-03 | Nkk Corp | 曲げ加工性及び衝撃特性の優れた超高強度冷延鋼板 |
US6368728B1 (en) * | 1998-11-18 | 2002-04-09 | Kawasaki Steel Corporation | Galvannealed steel sheet and manufacturing method |
JP3872621B2 (ja) | 1999-11-05 | 2007-01-24 | 新日本製鐵株式会社 | 自動車車体用亜鉛系メッキ鋼板 |
KR100451247B1 (ko) * | 2002-11-06 | 2004-10-13 | 엘지전자 주식회사 | 전기밥솥 |
JP4235030B2 (ja) * | 2003-05-21 | 2009-03-04 | 新日本製鐵株式会社 | 局部成形性に優れ溶接部の硬さ上昇を抑制した引張強さが780MPa以上の高強度冷延鋼板および高強度表面処理鋼板 |
JP4528137B2 (ja) * | 2004-03-19 | 2010-08-18 | 新日本製鐵株式会社 | 穴拡げ性に優れた高強度高延性薄鋼板の製造方法 |
JP4442811B2 (ja) | 2004-04-06 | 2010-03-31 | 鵬翔株式会社 | 強撚糸織物の製造方法 |
JP4254663B2 (ja) | 2004-09-02 | 2009-04-15 | 住友金属工業株式会社 | 高強度薄鋼板およびその製造方法 |
JP4445365B2 (ja) | 2004-10-06 | 2010-04-07 | 新日本製鐵株式会社 | 伸びと穴拡げ性に優れた高強度薄鋼板の製造方法 |
JP4791248B2 (ja) | 2005-05-24 | 2011-10-12 | 株式会社ディスコ | レーザー加工装置 |
JP2007016319A (ja) | 2006-08-11 | 2007-01-25 | Sumitomo Metal Ind Ltd | 高張力溶融亜鉛めっき鋼板とその製造方法 |
JP5223360B2 (ja) * | 2007-03-22 | 2013-06-26 | Jfeスチール株式会社 | 成形性に優れた高強度溶融亜鉛めっき鋼板およびその製造方法 |
RU2361936C1 (ru) * | 2008-01-09 | 2009-07-20 | Открытое акционерное общество "Северсталь" (ОАО "Северсталь" | Способ производства горячеоцинкованного проката повышенной прочности |
JP5369663B2 (ja) * | 2008-01-31 | 2013-12-18 | Jfeスチール株式会社 | 加工性に優れた高強度溶融亜鉛めっき鋼板およびその製造方法 |
JP5071173B2 (ja) | 2008-03-11 | 2012-11-14 | 住友金属工業株式会社 | 溶融亜鉛めっき鋼板およびその製造方法 |
JP5391572B2 (ja) | 2008-04-08 | 2014-01-15 | 新日鐵住金株式会社 | 冷延鋼板および溶融めっき鋼板ならびに該鋼板の製造方法 |
JP5504643B2 (ja) | 2008-08-19 | 2014-05-28 | Jfeスチール株式会社 | 加工性に優れた高強度溶融亜鉛めっき鋼板およびその製造方法 |
JP5206244B2 (ja) | 2008-09-02 | 2013-06-12 | 新日鐵住金株式会社 | 冷延鋼板 |
JP5228722B2 (ja) | 2008-09-10 | 2013-07-03 | 新日鐵住金株式会社 | 合金化溶融亜鉛めっき鋼板およびその製造方法 |
CA2781815C (en) * | 2009-11-30 | 2015-04-14 | Nippon Steel Corporation | High strength steel plate with ultimate tensile strength of 900 mpa or more excellent in hydrogen embrittlement resistance and method of production of same |
JP5644095B2 (ja) * | 2009-11-30 | 2014-12-24 | 新日鐵住金株式会社 | 延性及び耐遅れ破壊特性の良好な引張最大強度900MPa以上を有する高強度鋼板および高強度冷延鋼板の製造方法、高強度亜鉛めっき鋼板の製造方法 |
US9745639B2 (en) * | 2011-06-13 | 2017-08-29 | Kobe Steel, Ltd. | High-strength steel sheet excellent in workability and cold brittleness resistance, and manufacturing method thereof |
-
2012
- 2012-07-27 CN CN201280037618.4A patent/CN103717773B/zh active Active
- 2012-07-27 RU RU2014106991/02A patent/RU2569615C2/ru not_active IP Right Cessation
- 2012-07-27 WO PCT/JP2012/069260 patent/WO2013018739A1/ja active Application Filing
- 2012-07-27 KR KR1020147003572A patent/KR101597473B1/ko active Active
- 2012-07-27 ES ES12820441T patent/ES2727865T3/es active Active
- 2012-07-27 US US14/234,826 patent/US9234268B2/en active Active
- 2012-07-27 CA CA2842897A patent/CA2842897C/en not_active Expired - Fee Related
- 2012-07-27 JP JP2013501959A patent/JP5273324B1/ja active Active
- 2012-07-27 BR BR112014001994A patent/BR112014001994A2/pt not_active IP Right Cessation
- 2012-07-27 PL PL12820441T patent/PL2738280T3/pl unknown
- 2012-07-27 EP EP12820441.9A patent/EP2738280B1/en active Active
- 2012-07-27 MX MX2014000882A patent/MX360332B/es active IP Right Grant
- 2012-07-30 TW TW101127432A patent/TWI493055B/zh not_active IP Right Cessation
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007009317A (ja) * | 2005-05-31 | 2007-01-18 | Jfe Steel Kk | 伸びフランジ成形性に優れた高強度冷延鋼板および溶融亜鉛めっき鋼板とそれらの製造方法 |
JP2009228128A (ja) * | 2008-02-29 | 2009-10-08 | Jfe Steel Corp | 冷延鋼板およびその製造方法 |
JP2010150580A (ja) * | 2008-12-24 | 2010-07-08 | Jfe Steel Corp | 鋼板及びその製造方法 |
JP2011111675A (ja) * | 2009-11-30 | 2011-06-09 | Nippon Steel Corp | 耐水素脆化特性に優れた引張最大強度900MPa以上の高強度鋼板および高強度冷延鋼板の製造方法、高強度亜鉛めっき鋼板の製造方法 |
Cited By (39)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9840749B2 (en) | 2012-03-02 | 2017-12-12 | Jfe Steel Corporation | High strength galvanized steel sheet and method for manufacturing the same |
JP2013181225A (ja) * | 2012-03-02 | 2013-09-12 | Jfe Steel Corp | 高強度溶融亜鉛めっき鋼板及びその製造方法 |
JP2015528058A (ja) * | 2012-07-10 | 2015-09-24 | ティッセンクルップ スチール ヨーロッパ アクチェンゲゼルシャフトThyssenKrupp Steel Europe AG | 冷間圧延鋼板製品およびその製造方法 |
WO2014010415A1 (ja) * | 2012-07-12 | 2014-01-16 | 株式会社神戸製鋼所 | 降伏強度と成形性に優れた高強度溶融亜鉛めっき鋼板およびその製造方法 |
JP2014019879A (ja) * | 2012-07-12 | 2014-02-03 | Kobe Steel Ltd | 降伏強度と成形性に優れた高強度溶融亜鉛めっき鋼板およびその製造方法 |
US9863028B2 (en) | 2012-07-12 | 2018-01-09 | Kobe Steel, Ltd. | High-strength hot-dip galvanized steel sheet having excellent yield strength and formability |
US10072316B2 (en) * | 2012-10-18 | 2018-09-11 | Jfe Steel Corporation | High-strength cold-rolled steel sheet and method for producing the same |
US20160168656A1 (en) * | 2012-10-18 | 2016-06-16 | JFE Steel Coporation | High-strength cold-rolled steel sheet and method for producing the same |
JP2015113475A (ja) * | 2013-12-09 | 2015-06-22 | Jfeスチール株式会社 | 高強度冷延鋼板およびその製造方法 |
US10822684B2 (en) | 2014-11-05 | 2020-11-03 | Nippon Steel Corporation | Hot-dip galvanized steel sheet |
KR20170060139A (ko) * | 2014-11-05 | 2017-05-31 | 신닛테츠스미킨 카부시키카이샤 | 용융 아연 도금 강판 |
US10507629B2 (en) | 2014-11-05 | 2019-12-17 | Nippon Steel Corporation | Hot-dip galvanized steel sheet |
JPWO2016072477A1 (ja) * | 2014-11-05 | 2017-09-07 | 新日鐵住金株式会社 | 溶融亜鉛めっき鋼板 |
JPWO2016072479A1 (ja) * | 2014-11-05 | 2017-09-07 | 新日鐵住金株式会社 | 溶融亜鉛めっき鋼板 |
WO2016072479A1 (ja) * | 2014-11-05 | 2016-05-12 | 新日鐵住金株式会社 | 溶融亜鉛めっき鋼板 |
WO2016072477A1 (ja) * | 2014-11-05 | 2016-05-12 | 新日鐵住金株式会社 | 溶融亜鉛めっき鋼板 |
KR101950618B1 (ko) | 2014-11-05 | 2019-02-20 | 신닛테츠스미킨 카부시키카이샤 | 용융 아연 도금 강판 |
US10822683B2 (en) | 2014-11-05 | 2020-11-03 | Nippon Steel Corporation | Hot-dip galvanized steel sheet |
US10113223B2 (en) | 2014-11-05 | 2018-10-30 | Nippon Steel & Sumitomo Metal Corporation | Hot-dip galvanized steel sheet |
JP2017509789A (ja) * | 2014-12-19 | 2017-04-06 | ポスコPosco | 穴広げ性に優れた溶融亜鉛めっき鋼板、合金化溶融亜鉛めっき鋼板及びその製造方法 |
US10351924B2 (en) | 2014-12-19 | 2019-07-16 | Posco | Hot-dip galvanized steel sheet and hot-dip galvannealed steel sheet having improved hole expansion ratio, and manufacturing methods thereof |
US10501832B2 (en) * | 2015-04-22 | 2019-12-10 | Nippon Steel Corporation | Plated steel sheet |
JP2016216808A (ja) * | 2015-05-26 | 2016-12-22 | 新日鐵住金株式会社 | 成形性に優れた高強度鋼板及びその製造方法 |
KR20170137899A (ko) | 2015-05-29 | 2017-12-13 | 제이에프이 스틸 가부시키가이샤 | 고강도 냉연 강판, 고강도 도금 강판 및 이것들의 제조 방법 |
JP2017057460A (ja) * | 2015-09-16 | 2017-03-23 | 新日鐵住金株式会社 | 高強度合金化溶融亜鉛めっき鋼板と該鋼板用熱延鋼板及びそれらの製造方法 |
US10927429B2 (en) | 2015-12-15 | 2021-02-23 | Tata Steel Ijmuiden B.V. | High strength hot dip galvanised steel strip |
CN108474059A (zh) * | 2016-02-25 | 2018-08-31 | 新日铁住金株式会社 | 钢板的制造方法及钢板的连续退火装置 |
WO2017145322A1 (ja) * | 2016-02-25 | 2017-08-31 | 新日鐵住金株式会社 | 鋼板の製造方法及び鋼板の連続焼鈍装置 |
WO2018062342A1 (ja) * | 2016-09-30 | 2018-04-05 | Jfeスチール株式会社 | 高強度めっき鋼板及びその製造方法 |
JPWO2018062342A1 (ja) * | 2016-09-30 | 2018-09-27 | Jfeスチール株式会社 | 高強度めっき鋼板及びその製造方法 |
US11142805B2 (en) | 2016-09-30 | 2021-10-12 | Jfe Steel Corporation | High-strength coated steel sheet and method for manufacturing the same |
JP6458911B1 (ja) * | 2017-02-28 | 2019-01-30 | Jfeスチール株式会社 | 高強度鋼板およびその製造方法 |
WO2018159405A1 (ja) * | 2017-02-28 | 2018-09-07 | Jfeスチール株式会社 | 高強度鋼板およびその製造方法 |
US11208709B2 (en) | 2017-02-28 | 2021-12-28 | Jfe Steel Corporation | High-strength steel sheet and manufacturing method therefor |
WO2019167933A1 (ja) * | 2018-02-28 | 2019-09-06 | Jfeスチール株式会社 | 冷延鋼板及びその製造方法 |
JP6631762B1 (ja) * | 2018-02-28 | 2020-01-15 | Jfeスチール株式会社 | 冷延鋼板及びその製造方法 |
US11345974B2 (en) | 2018-02-28 | 2022-05-31 | Jfe Steel Corporation | Cold rolled steel sheet and method for manufacturing the same |
WO2020158065A1 (ja) * | 2019-01-30 | 2020-08-06 | Jfeスチール株式会社 | 高強度鋼板およびその製造方法 |
US12139771B2 (en) | 2019-01-30 | 2024-11-12 | Jfe Steel Corporation | High-strength steel sheet and method for producing the same |
Also Published As
Publication number | Publication date |
---|---|
KR101597473B1 (ko) | 2016-02-24 |
MX2014000882A (es) | 2014-02-20 |
BR112014001994A2 (pt) | 2017-02-21 |
ES2727865T3 (es) | 2019-10-21 |
MX360332B (es) | 2018-10-29 |
CA2842897A1 (en) | 2013-02-07 |
US20140212684A1 (en) | 2014-07-31 |
EP2738280A4 (en) | 2015-08-05 |
CA2842897C (en) | 2016-09-20 |
EP2738280B1 (en) | 2019-03-20 |
PL2738280T3 (pl) | 2019-08-30 |
RU2014106991A (ru) | 2015-09-10 |
JPWO2013018739A1 (ja) | 2015-03-05 |
CN103717773A (zh) | 2014-04-09 |
TWI493055B (zh) | 2015-07-21 |
JP5273324B1 (ja) | 2013-08-28 |
US9234268B2 (en) | 2016-01-12 |
KR20140041833A (ko) | 2014-04-04 |
CN103717773B (zh) | 2016-05-04 |
TW201309815A (zh) | 2013-03-01 |
RU2569615C2 (ru) | 2015-11-27 |
EP2738280A1 (en) | 2014-06-04 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP5273324B1 (ja) | 曲げ性に優れた高強度亜鉛めっき鋼板およびその製造方法 | |
US9702035B2 (en) | High-strength hot-dip galvanized steel sheet excellent in impact resistance property and manufacturing method thereof, and high-strength alloyed hot-dip galvanized steel sheet and manufacturing method thereof | |
JP5780171B2 (ja) | 曲げ性に優れた高強度冷延鋼板、高強度亜鉛めっき鋼板及び高強度合金化溶融亜鉛めっき鋼板とその製造方法 | |
JP5454746B2 (ja) | 高強度冷延鋼板及びその製造方法 | |
JP5252142B1 (ja) | 成形性に優れた高強度鋼板、高強度亜鉛めっき鋼板及びそれらの製造方法 | |
JP5352793B2 (ja) | 耐遅れ破壊特性に優れた高強度溶融亜鉛めっき鋼板およびその製造方法 | |
JP5510607B2 (ja) | 合金化溶融亜鉛めっき層およびそれを有する鋼板ならびにその製造方法 | |
JP5053157B2 (ja) | プレス成形性の良好な高強度高ヤング率鋼板、溶融亜鉛めっき鋼板、合金化溶融亜鉛めっき鋼板及び鋼管、並びに、それらの製造方法 | |
JP7173303B2 (ja) | 鋼板及びその製造方法 | |
US20170211163A1 (en) | High-strength steel sheet and production method for same, and production method for high-strength galvanized steel sheet | |
US11230744B2 (en) | Steel sheet, plated steel sheet, method for producing hot-rolled steel sheet, method for producing cold-rolled full hard steel sheet, method for producing steel sheet, and method for producing plated steel sheet | |
CN113272461B (zh) | 钢板 | |
EP2740813A1 (en) | Hot-dip galvanized steel sheet and production method therefor | |
JP7364963B2 (ja) | 鋼板およびその製造方法 | |
WO2022054221A1 (ja) | 鋼板およびその製造方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 201280037618.4 Country of ref document: CN |
|
ENP | Entry into the national phase |
Ref document number: 2013501959 Country of ref document: JP Kind code of ref document: A |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 12820441 Country of ref document: EP Kind code of ref document: A1 |
|
WWE | Wipo information: entry into national phase |
Ref document number: MX/A/2014/000882 Country of ref document: MX |
|
ENP | Entry into the national phase |
Ref document number: 2842897 Country of ref document: CA |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
ENP | Entry into the national phase |
Ref document number: 20147003572 Country of ref document: KR Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: IDP00201401037 Country of ref document: ID |
|
ENP | Entry into the national phase |
Ref document number: 2014106991 Country of ref document: RU Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 14234826 Country of ref document: US |
|
REG | Reference to national code |
Ref country code: BR Ref legal event code: B01A Ref document number: 112014001994 Country of ref document: BR |
|
ENP | Entry into the national phase |
Ref document number: 112014001994 Country of ref document: BR Kind code of ref document: A2 Effective date: 20140127 |