US20180044750A1 - Post Annealed High Tensile Strength Coated Steel Sheet having Improved Yield Strength and Hole Expansion - Google Patents
Post Annealed High Tensile Strength Coated Steel Sheet having Improved Yield Strength and Hole Expansion Download PDFInfo
- Publication number
- US20180044750A1 US20180044750A1 US15/552,485 US201615552485A US2018044750A1 US 20180044750 A1 US20180044750 A1 US 20180044750A1 US 201615552485 A US201615552485 A US 201615552485A US 2018044750 A1 US2018044750 A1 US 2018044750A1
- Authority
- US
- United States
- Prior art keywords
- steel sheet
- coated
- cold rolled
- mpa
- annealing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000137 annealing Methods 0.000 claims abstract description 116
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 110
- 239000010959 steel Substances 0.000 claims abstract description 110
- 238000000576 coating method Methods 0.000 claims abstract description 21
- 239000011701 zinc Substances 0.000 claims abstract description 20
- 239000011248 coating agent Substances 0.000 claims abstract description 17
- 239000010960 cold rolled steel Substances 0.000 claims abstract description 16
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 15
- 238000005097 cold rolling Methods 0.000 claims abstract description 6
- 229910001297 Zn alloy Inorganic materials 0.000 claims abstract description 3
- 229910045601 alloy Inorganic materials 0.000 description 84
- 239000000956 alloy Substances 0.000 description 84
- 238000005496 tempering Methods 0.000 description 58
- 229910000859 α-Fe Inorganic materials 0.000 description 33
- 229910052799 carbon Inorganic materials 0.000 description 26
- 239000000203 mixture Substances 0.000 description 26
- 230000000694 effects Effects 0.000 description 24
- 238000007792 addition Methods 0.000 description 17
- 229910000734 martensite Inorganic materials 0.000 description 17
- 229910052710 silicon Inorganic materials 0.000 description 17
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 14
- 239000011572 manganese Substances 0.000 description 14
- 238000010438 heat treatment Methods 0.000 description 12
- 229910052748 manganese Inorganic materials 0.000 description 10
- 229910001566 austenite Inorganic materials 0.000 description 9
- 229910052804 chromium Inorganic materials 0.000 description 8
- 230000007423 decrease Effects 0.000 description 8
- 239000000463 material Substances 0.000 description 8
- 229910052750 molybdenum Inorganic materials 0.000 description 8
- 238000012360 testing method Methods 0.000 description 8
- 230000006698 induction Effects 0.000 description 7
- 229910052742 iron Inorganic materials 0.000 description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- 229910052782 aluminium Inorganic materials 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 6
- 238000001816 cooling Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 238000005096 rolling process Methods 0.000 description 6
- 239000011265 semifinished product Substances 0.000 description 6
- 238000002791 soaking Methods 0.000 description 6
- 230000001747 exhibiting effect Effects 0.000 description 5
- 230000009467 reduction Effects 0.000 description 5
- 238000004088 simulation Methods 0.000 description 5
- 239000006104 solid solution Substances 0.000 description 5
- 238000005275 alloying Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000003723 Smelting Methods 0.000 description 3
- 229910052796 boron Inorganic materials 0.000 description 3
- 238000005266 casting Methods 0.000 description 3
- 238000005246 galvanizing Methods 0.000 description 3
- 238000005244 galvannealing Methods 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 230000000717 retained effect Effects 0.000 description 3
- 238000009628 steelmaking Methods 0.000 description 3
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 229910001563 bainite Inorganic materials 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 239000010432 diamond Substances 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 238000010191 image analysis Methods 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000003381 stabilizer Substances 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 229910000976 Electrical steel Inorganic materials 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 238000003303 reheating Methods 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
Images
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
- C23C2/04—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
- 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
- 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
-
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
- C21D1/20—Isothermal quenching, e.g. bainitic hardening
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/25—Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten")
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/008—Heat treatment of ferrous alloys containing Si
-
- 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
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- 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
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0236—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
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
-
- 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
- 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
- C22C38/02—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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
-
- 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
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
-
- 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
- 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
-
- 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
-
- 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
- C23C2/29—Cooling or quenching
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
- C23C2/36—Elongated material
- C23C2/40—Plates; Strips
-
- 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
Definitions
- the present invention relates to steel sheet material. More specifically the present invention relates to steel sheet material having a zinc coating thereon. Most specifically, the present invention relates to steel sheet material having a zinc coating thereon having been post annealed after the coating process to increase yield strength and hole expansion of the coated steel sheet as compared with the as coated sheet.
- the present invention relates to a cold rolled, coated and post annealed steel sheet.
- the cold rolled steel sheet may comprise (in wt. %): C—0.1-0.3%; Mn—1-3%; Si—0.5-3.5%; Al—0.05-1.5%; Mo+Cr is between 0-1.0%; and Mo+Cr is between 0.2-0.5%.
- the steel sheet may be coated with a zinc or zinc alloy coating.
- the coated steel sheet may be formed by cold rolling, zinc coating the cold rolled sheet and annealing said steel sheet after application of said zinc coating.
- the annealing may be performed at a temperature between 150-650° C., preferably between 150-450° C., and most preferably between 200-400° C.
- the annealing may be performed for a period of time sufficient to increase the yield strength of the annealed cold rolled coated steel sheet by at least 30% and preferably by at least 40% compared to the as coated cold rolled steel sheet.
- the annealing may be performed for a period of time sufficient to increase the hole expansion of the annealed cold rolled coated steel sheet by at least 80% and preferably 95% compared to the as coated cold rolled steel sheet.
- the annealing may be performed for a period of time sufficient to increase the total elongation of the annealed cold rolled coated steel sheet by at least 25% and preferably 40% compared with the as coated sheet.
- the cold rolled steel sheet may preferably comprises C—0.15-0.25%; Mn—2-2.5%; Si—1.5-2.5%; and Al—0.05-1.0%.
- FIG. 1 plots temperature in ° C. vs time in seconds for a typical CL HDGL thermal cycle used in simulations for the present invention
- FIG. 2 a plots yield strength YS in MPa vs annealing temperature in ° C. for sample alloys 5, 6 and 7.
- FIG. 2 b plots tensile strength TS in MPa vs annealing temperature in ° C. for sample alloys 5, 6 and 7;
- FIG. 2 c plots total elongation TE in % vs annealing temperature in ° C. for sample alloys 5, 6 and 7;
- FIG. 2 d plots total elongation TE in % vs tensile strength TS in MPa for sample alloys 5, 6 and 7;
- FIG. 3 a plots yield strength YS in MPa vs annealing temperature in ° C. for sample alloys 12, 13 and 14;
- FIG. 3 b plots tensile strength TS in MPa vs annealing temperature in ° C. for sample alloys 12, 13 and 14;
- FIG. 3 c plots total elongation TE in % vs annealing temperature in ° C. for sample alloys 12, 13 and 14;
- FIG. 3 d plots total elongation TE in % vs tensile strength TS in MPa for sample alloys 12, 13 and 14;
- FIG. 4 a plots volume of ferrite in % and total elongation TE in % vs weight % Si for samples exhibiting TS of about 1180-1300 MPa
- FIG. 4 a plots tensile strength TS in MPa and total elongation TE in % vs volume of ferrite in % samples exhibiting TS of about 1180-1300 MPa;
- FIG. 5 a plots yield strength YS in MPa vs annealing temperature in ° C. for sample alloys 8, 9, 11 and 12;
- FIG. 5 b plots tensile strength TS in MPa vs annealing temperature in ° C. for sample alloys 8, 9, 11 and 12;
- FIG. 5 c plots total elongation TE in % vs annealing temperature in ° C. for sample alloys 8, 9, 11 and 12;
- FIG. 5 d plots total elongation TE in % vs tensile strength TS in MPa for sample alloys 8, 9, 11 and 12;
- FIG. 6 a plots yield strength YS in MPa vs annealing temperature in ° C. for sample alloys 16, 17 and 18;
- FIG. 6 b plots tensile strength TS in MPa vs annealing temperature in ° C. for sample alloys 16, 17 and 18;
- FIG. 6 c plots total elongation TE in % vs annealing temperature in ° C. for sample alloys 16, 17 and 18;
- FIG. 6 d plots total elongation TE in % vs tensile strength TS in MPa for sample alloys 16, 17 and 18;
- FIG. 7 a plots yield strength YS in MPa vs annealing temperature in ° C. for sample alloys 8, 9 and 10;
- FIG. 7 b plots tensile strength TS in MPa vs annealing temperature in ° C. for sample alloys 8, 9 and 10;
- FIG. 7 c plots total elongation TE in % vs annealing temperature in ° C. for sample alloys 8, 9 and 10;
- FIG. 7 d plots total elongation TE in % vs tensile strength TS in MPa for sample alloys 8, 9 and 10;
- FIG. 8 plots the total elongation TE in % vs yield strength YS (squares) and tensile strength TS (diamonds) in MPa for all sample alloys;
- FIG. 9 a plots yield strength YS in MPa vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C;
- FIG. 9 b plots tensile strength TS in MPa vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C;
- FIG. 9 c plots uniform elongation UEL in % vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C;
- FIG. 9 d plots total elongation EL in % vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C;
- FIG. 10 a plots yield strength YS in MPa vs post batch annealing temperature in ° C. for sample alloys 9 and 10 and a sample alloy containing 0.15% C;
- FIG. 10 b plots tensile strength TS in MPa vs post batch annealing temperature in ° C. for sample alloys 9 and 10 and a sample alloy containing 0.15% C;
- FIG. 10 c plots uniform elongation UEL in % vs post batch annealing temperature in ° C. for sample alloys 9 and 10 and a sample alloy containing 0.15% C;
- FIG. 10 d plots total elongation EL in % vs post batch annealing temperature in ° C. for sample alloys 9 and 10 and a sample alloy containing 0.15% C;
- FIG. 11 a plots the yield strength YS and tensile strength TS in MPa vs post batch annealing temperature for samples with a pre batch annealing TS of >1180 MPa;
- FIG. 11 b plots the total elongation TE in % and hole expansion in % vs post batch annealing temperature in ° C. for samples with a pre batch annealing TS of >1180 Mpa;
- FIG. 12 plots temperature in ° C. vs time in hours for a batch annealing cycle from a specific steel-making plant.
- the carbon range of steel materials of the present invention is 0.1-0.3 wt %.
- the preferred range is about 0.15-0.25%.
- the minimum of 0.15% is required to achieve TRIP effect by retained austenite and strength.
- the maximum amount of 0.25% allows for better weldability.
- the manganese range of steel materials of the present invention is 1-3%, with 2-2.5% preferred.
- the minimum of 2% is necessary to achieve TS>980 MPa and the maximum amount of 2.5% is limited due to weldability and banded structure.
- the silicon range of steel materials of the present invention is 0.5-3.5%, with 1.5-2.5% preferred.
- the minimum of 1.5% is necessary to achieve the TRIP effect, while the maximum of 2.5% is limited due to weldability and Zn coatability.
- the aluminum range of steel materials of the present invention is 0.05-1.5%, with 0.05-1.0% preferred.
- the minimum of 0.5% is necessary to achieve the TRIP effect, while the maximum of 1% is limited by the required soak temperature at hot dip Zn coating line.
- the remainder of the steel is iron with residuals at levels based on practical experiences.
- the process condition for forming the coated steel material is standard and there are no special requirements from the steel making stage to hot dip Zn coating.
- the properties of the hot dip Zn coated steel sheet are then improved by post batch annealing.
- the peak temperature of the post batch annealing should be between 150-650° C., more preferably between 150-450° C., most preferably between 200-400° C.
- the preferred minimum temperature of 200° C. is necessary to achieve better formability and the preferred maximum of 400° C. is to better avoid the possibility of degradation of the Zn coating.
- the ingots were produced by vacuum induction melting.
- the composition of the investigated steels is summarized in Table 1.
- the ingots have about 0.18-0.21% C at various ranges of Mn, Si, Al, Cr, Mo, Nb.
- the effect of each element on the mechanical properties and microstructure is discussed herein below.
- Table 3 shows JIS-T tensile properties of selected full hard steels. Tensile strengths TS of about 1200 to about 1350 MPa (170-195 ksi) are observed.
- FIG. 1 plots temperature in ° C. vs time in seconds for a typical CL HDGL thermal cycle used in simulations by the present inventors. A wide range of annealing temperatures was investigated. Three thermocouples were used to ensure thermal homogeneity within the sample during reheating and cooling.
- FIGS. 2 a -2 d and 3 a -3 d illustrate the effects of Si content and annealing temperature on the tensile properties of these two different sets of steels.
- FIG. 2 a plots yield strength YS in MPa vs annealing temperature in ° C. for sample alloys 5, 6 and 7.
- FIG. 2 b plots tensile strength TS in MPa vs annealing temperature in ° C. for sample alloys 5, 6 and 7.
- FIG. 2 c plots total elongation TE in % vs annealing temperature in ° C. for sample alloys 5, 6 and 7.
- FIG. 2 d plots total elongation TE in % vs tensile strength TS in MPa for sample alloys 5, 6 and 7.
- FIG. 3 a plots yield strength YS in MPa vs annealing temperature in ° C. for sample alloys 12, 13 and 14.
- FIG. 3 b plots tensile strength TS in MPa vs annealing temperature in ° C. for sample alloys 12, 13 and 14.
- FIG. 3 c plots total elongation TE in % vs annealing temperature in ° C. for sample alloys 12, 13 and 14.
- FIGS. 3 d plots total elongation TE in % vs tensile strength TS in MPa for sample alloys 12, 13 and 14.
- the amount of Si in the first set ( FIGS. 2 a -2 d ) varies from 1.5 to 2.5% in a 0.2C-1.8Mn-0.15Mo-0.02Nb matrix, and the other set ( FIGS. 3 a -3 d ) has 1.2 to 2.0% Si in a matrix comprised of 0.2C-1.5Mn-0.3Mo-0.7Al-0.02Nb.
- an increase in Si content from 1.5 to 2.0% significantly increases strength (yield strengty [YS], tensile strength [TS]) while marginally decreasing ductility.
- Yield strengty [YS], tensile strength [TS]) is further increased from 2.0 to 2.5%.
- a portion of the strength increase obtained upon increasing the Si content from 1.5 to 2.0% can be attributed to the solid solution hardening in these alloys; about 40-50 MPa for 0.5% Si addition.
- the increase in Si from 1.5 to 2.0 and 2.5% is also expected to increase Ac 1 from 747° C. to 762° C. and 776° C. and Ac 3 from 910° C. to 933° C. and 955° C., respectively, using Andrew's equations.
- the increase in anneal temperature from 800° C. to 825° C. and 850° C. is associated with a substantial increase in austenite formation.
- austenite content increases, it is diluted in carbon and is therefore less hardenable and more amenable to decomposition during the subsequent cooling. This behavior could explain the loss in strength with an increase in anneal temperature.
- Si content in the steel is increased from 1.5 to 2.0 and 2.5%, less austenite is formed at the same anneal temperature and it is also more hardenable. This could explain the relative stability in strength across annealing temperatures in the higher Si steels.
- the strengths in the 2.0 and 2.5% Si bearing steels appear to be similar. That is, the higher solid solution strengthening in the 2.5% silicon steel is also associated with a relatively smaller volume fraction of martensite in comparison to the 2.0% Si bearing steel.
- the increase in Si from 1.5 to 2.0/2.5% is believed to enhance the hardenability of the steel as well.
- An additional potential reason for the difference in YS between 1.5Si and 2.0/2.5Si bearing steels may be attributable to the delay in the auto-tempering of martensite as the Si content in the steel is increased.
- the effect of Si among these alloys may be connected with other alloy effects.
- the increase in Si from 1.2 to 2.0% in this base composition improves the balance between strength and ductility.
- the steels with a Si content of about 1.2-1.5% Si doesn't make TS>1180 MPa as the 0.7% Al addition substantially increasing the Ac 1 and Ac 3 temperatures.
- the steel with 2.0% Si demonstrates total elongation (TE)>16% at TS>1180 MPa. Since there is no significant amount of retained austenite that could result in substantial TRIP effect, the better ductility of the steel at higher Si content is attributed to Si solid solution hardening that allowed the attainment of the prescribed strength with less amount of martensite.
- FIG. 4 a shows the effect of Si addition on fraction of ferrite and TE in the samples having TS of about 1180-1300 MPa.
- FIG. 4 a plots volume of ferrite in % and total elongation TE in % vs weight % Si for samples exhibiting TS of about 1180-1300 MPa.
- FIG. 4 a plots tensile strength TS in MPa and total elongation TE in % vs volume of ferrite in % samples exhibiting TS of about 1180-1300 MPa.
- An increase in Si content reduces the volume fraction of martensite (increasing ferrite), and consequently improves ductility.
- TS and TE The best combination of TS and TE (TS of 1200 MPa/TE of 16-18%) can be achieved at Vf (volume of ferrite) of about 70% in alloy 14 containing 2.0% Si.
- Vf volume of ferrite
- the ferrite fraction of about 70% is considerably higher compared to about 30-40% ferrite in prior art CR DP T1180 with TE of 10-13%.
- the amount of Si should be optimized according to the overall alloy combination, in favor of a larger annealing process window, better weldability, and acceptable coatability.
- FIG. 4 b plots the TS and TE as a function of ferrite fraction in samples exhibiting TS of about 1180-1300 MPa. It should be noted that the ferrite amount was measured by image analysis employing only one field per sample. Therefore, the observed trend and not to the absolute volume fraction of ferrite as a function of silicon addition provides the most important information.
- Mn, Cr and Mo increase the hardenability of the steel.
- the reduction in the amount of austenite to ferrite/bainite decomposition results in a higher fraction of martensite. Comparing investigated steels, it is possible to assess the relative hardenability of Mn, Cr and Mo.
- FIGS. 5 a -5 d show the effect of various Mo and Cr additions on the tensile properties of 0.2C-1.5Mn-1.2Si-0.65Al-0.02Nb containing steel.
- FIG. 5 a plots yield strength YS in MPa vs annealing temperature in ° C. for sample alloys 8, 9, 11 and 12.
- FIG. 5 b plots tensile strength TS in MPa vs annealing temperature in ° C. for sample alloys 8, 9, 11 and 12.
- FIG. 5 c plots total elongation TE in % vs annealing temperature in ° C. for sample alloys 8, 9, 11 and 12.
- FIG. 5 a plots yield strength YS in MPa vs annealing temperature in ° C. for sample alloys 8, 9, 11 and 12.
- FIG. 5 b plots tensile strength TS in MPa vs annealing temperature in ° C. for sample alloys 8, 9, 11 and 12.
- FIG. 6 a -6 d compare the effects of 0.15Mo, 0.35Cr and increased (+0.2) Mn on the tensile properties of steels with a base composition of 0.2C-2.3Mn-1.0Si.
- FIG. 6 a plots yield strength YS in MPa vs annealing temperature in ° C. for sample alloys 16, 17 and 18.
- FIG. 6 b plots tensile strength TS in MPa vs annealing temperature in ° C. for sample alloys 16, 17 and 18.
- FIG. 6 c plots total elongation TE in % vs annealing temperature in ° C. for sample alloys 16, 17 and 18.
- FIGS. 7 a -7 d show the effect of B addition on the tensile properties of the steel.
- FIG. 7 a plots yield strength YS in MPa vs annealing temperature in ° C. for sample alloys 8, 9 and 10.
- FIG. 7 b plots tensile strength TS in MPa vs annealing temperature in ° C. for sample alloys 8, 9 and 10.
- FIG. 7 c plots total elongation TE in % vs annealing temperature in ° C. for sample alloys 8, 9 and 10.
- the present inventors' objective is to achieve as high as possible total elongation at TS>1180 MPa.
- the fraction of ferrite in the microstructure should be maximized since the ferrite seems to be the main contributor to ductility, as shown in FIG. 4 b (even though the retained austenite contributes as well).
- higher ferrite fraction makes the steels softer due to its lower strength. Therefore, the ferrite and martensite should be hardened as much as possible to reach TS>1180 MPa in conjunction with superior ductility.
- the metallurgy has to be sound in terms of manufacturability on both the producer and customer fronts. The effect of Si addition on the solid solution hardening of ferrite has been well illustrated.
- FIG. 8 shows the balance of TS-TE and YS-TE.
- FIG. 8 plots the total elongation TE in % vs yield strength YS (squares) and tensile strength TS (diamonds) in MPa for all sample alloys. The best combination is TS about 1180-1250 MPa, YS about 550-650 MPa, and TE about 15-18%. Based on the tensile results, the composition: 0.2C-1.5Mn-1.3Si-0.65Al-0.3Mo-0.02Nb is considered as the best combination of TS and TE.
- the hot band strength for this composition (CT 620° C.) is YS about 630 MPa, and TS about 800 MPa.
- the properties after annealing are: YS about 550 MPa, TS about 1250 MPa, and TE about 14-16%.
- the selected composition (0.2C-1.5Mn-1.3Si-0.65Al-0.3Mo-0.02Nb) raises two concerns for GA 1180 HF production; higher C than the desired maximum limit of 0.19% C and high alloy cost due to 0.3Mo addition. Therefore, a modified composition (0.18C-1.8Mn-1.5Si-0.65Al-0.02Nb-0.15Mo—shown in Table 4) has been investigated.
- the modified alloy substitutes 0.3% Si and 0.3% Mn for of 0.15% of the Mo.
- Table 5 shows the tensile properties of modified alloy 7 which is very similar to alloy 8.
- the annealed tensile properties of modified alloy 8 are similar to those of alloy 8, as shown in Table 6. Therefore, this modification is considered as reasonable.
- FIGS. 9 a -9 d show the effect of post batch annealing on tensile properties.
- FIG. 9 a plots yield strength YS in MPa vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C.
- FIG. 9 b plots tensile strength TS in MPa vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C.
- FIG. 9 a plots yield strength YS in MPa vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C.
- FIG. 9 b plots tensile strength TS in MPa vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C.
- FIG. 9 c plots uniform elongation UEL in % vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C.
- FIG. 9 d plots total elongation EL in % vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C.
- An increase in batch annealing temperature (BAT) significantly improves YS, but at a cost of UEL. It is worth mentioning that TE and TS slightly decrease. In addition, hole expansion improves to about 17% at BAT of 200° C., however it still not enough and significantly below the desired target of 30%. The results indicate the need for higher BAT such as 250° C. and higher. It should be noted that there may be non-uniform temperature issues using the batch anneal process (hot/cold spots during multi stack anneal).
- FIGS. 10 a -10 d show the effect of short time induction annealing on the tensile properties of the steel.
- FIG. 10 a plots yield strength YS in MPa vs post batch annealing temperature in ° C. for sample alloys 9 and 10 and a sample alloy containing 0.15% C.
- FIG. 10 b plots tensile strength TS in MPa vs post batch annealing temperature in ° C. for sample alloys 9 and 10 and a sample alloy containing 0.15% C.
- FIG. 10 c plots uniform elongation UEL in % vs post batch annealing temperature in ° C. for sample alloys 9 and 10 and a sample alloy containing 0.15% C.
- FIG. 10 d plots total elongation EL in % vs post batch annealing temperature in ° C.
- FIGS. 11 a -11 b show the effect of post tempering temperature on tensile properties and hole expansion.
- FIG. 11 a plots the yield strength YS and tensile strength TS in MPa vs post batch annealing temperature for samples with a pre batch annealing TS of >1180 MPa.
- FIG. 11 b plots the total elongation TE in % and hole expansion in % vs post batch annealing temperature in ° C. for samples with a pre batch annealing TS of >1180 MPa.
- FIG. 12 plots temperature in ° C. vs time in hours for a batch annealing cycle from a specific steel-making plant. This cycle with an intended temperature of 260° C. (500° F.) has no temperature differential between hot and cold spots due to the long annealing time.
- Table 7 summarizes the JIS-T tensile properties and hole expansion data.
- This low temperature post batch annealing introduces non-uniformity of strength and ductility by about 20-30 MPa and about 1%, respectively. This non-uniformity is quite similar to the expected variation along the coil length. However, it requires a higher initial TS to ensure TS>1180 MPa after post batch annealing. The increase in Mn by 0.2% will provide an additional tensile strength of about 80 MPa to accommodate for the tensile drop upon post batch annealing.
- Semi-finished products have been produced from steel castings.
- the chemical compositions of the semi-finished products, expressed in weight percent, are shown in Table 8 below.
- the rest of the steel compositions in Table 8 consists in iron and inevitable impurities resulting from the smelting.
- Ingots of composition A to D were initially hot rolled to 20 mm thick plates. Then, the plates were reheated and hot-rolled again down to 3.8 mm. The hot rolled steel plates were then cold rolled and annealed.
- the process parameters undergone are shown hereunder:
- microstructure of steel sheets A to D contains ferrite (including bainitic ferrite), martensite and MA islands in surface proportion given in the Table 9 below, before being submitted to post tempering by two different ways. Such surface fractions are unchanged after post tempering which is only modifying the carbon concentration inside those phases.
- Post tempering of a set of steel sheets A was performed by heating such steels as a coil in a batch annealing furnace. The heating and cooling rates before and after tempering were done at a rate of 25° C./h isothermal tempering was done at the desired temperature for 5 hours.
- Post tempering of a set of steel sheets B to D was performed by induction heating the steel sheets to reach the desired temperature, which was maintained during the times specified in Table 11.
- Semi-finished products have been produced from steel castings.
- the chemical composition of the semi-finished products, expressed in weight percent, is shown in Table 12 below.
- the rest of the steel composition in Table 5 consists in iron and inevitable impurities resulting from the smelting.
- Ingot of composition 5 was initially hot rolled to 20 mm thick plates. Then, the plates were reheated and hot-rolled again down to 3.8 mm. The hot rolled steel plates were then cold rolled and annealed.
- the process parameters undergone are shown hereunder:
- microstructure of steel sheets E contains ferrite (including bainitic ferrite), martensite and MA islands in surface proportion according to the invention, before being submitted to post tempering by batch annealing. Such surface fractions are unchanged after post tempering which is only modifying the carbon concentration inside those phases.
- Post tempering of a set of steel sheets 5 was performed by heating such steels as a coil in a batch annealing furnace. Isothermal tempering was done at the desired temperature for 5 hours. Temper rolling was then performed with 0.3% elongation.
- Semi-finished products have been produced from a steel casting.
- the chemical composition of the semi-finished products, expressed in weight percent, is shown in Table 14 below.
- the rest of the steel composition in Table 14 consists in iron and inevitable impurities resulting from the smelting.
- Ingots of composition F were initially hot rolled to 4 mm thick plates. The hot rolled steel plates were then cold rolled and annealed. The process parameters undergone are shown hereunder:
- the microstructure of steel sheet F contains 71% of ferrite (including bainitic ferrite), 20% of martensite and 9% of austenite before being submitted to post tempering by two different ways. Such surface fractions are unchanged after post tempering which is only modifying the carbon concentration inside those phases.
- Post tempering of a first set of steel sheets E was performed by heating such steels as a coil in a batch annealing furnace. Isothermal tempering was done at the desired temperature for 8 hours.
- Post tempering of a second set of steel sheets E was performed by induction heating the steel sheets to reach the desired temperature, which was maintained during the times specified in table 16.
- Table 17 shows the properties of a zinc coated steel sheet as coated and after post annealing at 288° C. As can be seen the annealing has increased the yield strength by at least 30% compared with the as coated sheet, preferably 40%. The annealing has also increased the total elongation by at least 25% compared with the as coated sheet, preferably at least 40%. Finally, the annealing has increased the hole expansion by at least 80% compared with the as coated sheet, preferably 95%.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
- This application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application No. 62/120,426 filed Feb. 25, 2015.
- The present invention relates to steel sheet material. More specifically the present invention relates to steel sheet material having a zinc coating thereon. Most specifically, the present invention relates to steel sheet material having a zinc coating thereon having been post annealed after the coating process to increase yield strength and hole expansion of the coated steel sheet as compared with the as coated sheet.
- As the use of high strength steels increases in automotive applications, there is a growing demand for steels of increased strength without sacrificing formability. Growing demands for weight saving and safety requirement motivate intensive elaborations of new concepts of automotive steels that can achieve higher ductility simultaneously with higher strength in comparison with the existing Advanced High Strength Steels (AHSS).
- Auto manufactures would like to be able to utilize a GI/GA 1180 HF steel grade in vehicles. This product is for a cold stamping application. Presently available steel compositions have been investigated to produce a GA HF T1180 grade steel. Based on laboratory studies which simulated the CL HDGL thermal profile, the as annealed properties cannot meet the tensile property (mostly YS) and hole expansion requirements.
- Thus there is a need in the art for a coated 1180+MPa tensile strength, steel sheet with high formability. This requires an improvement in yield strength and hole expansion performance over steels currently in production.
- The present invention relates to a cold rolled, coated and post annealed steel sheet. The cold rolled steel sheet may comprise (in wt. %): C—0.1-0.3%; Mn—1-3%; Si—0.5-3.5%; Al—0.05-1.5%; Mo+Cr is between 0-1.0%; and Mo+Cr is between 0.2-0.5%. The steel sheet may be coated with a zinc or zinc alloy coating. The coated steel sheet may be formed by cold rolling, zinc coating the cold rolled sheet and annealing said steel sheet after application of said zinc coating. The annealing may be performed at a temperature between 150-650° C., preferably between 150-450° C., and most preferably between 200-400° C. The annealing may be performed for a period of time sufficient to increase the yield strength of the annealed cold rolled coated steel sheet by at least 30% and preferably by at least 40% compared to the as coated cold rolled steel sheet.
- The annealing may be performed for a period of time sufficient to increase the hole expansion of the annealed cold rolled coated steel sheet by at least 80% and preferably 95% compared to the as coated cold rolled steel sheet.
- The annealing may be performed for a period of time sufficient to increase the total elongation of the annealed cold rolled coated steel sheet by at least 25% and preferably 40% compared with the as coated sheet.
- The cold rolled steel sheet may preferably comprises C—0.15-0.25%; Mn—2-2.5%; Si—1.5-2.5%; and Al—0.05-1.0%.
-
FIG. 1 plots temperature in ° C. vs time in seconds for a typical CL HDGL thermal cycle used in simulations for the present invention; -
FIG. 2a plots yield strength YS in MPa vs annealing temperature in ° C. forsample alloys -
FIG. 2b plots tensile strength TS in MPa vs annealing temperature in ° C. forsample alloys -
FIG. 2c plots total elongation TE in % vs annealing temperature in ° C. forsample alloys -
FIG. 2d plots total elongation TE in % vs tensile strength TS in MPa forsample alloys -
FIG. 3a plots yield strength YS in MPa vs annealing temperature in ° C. forsample alloys -
FIG. 3b plots tensile strength TS in MPa vs annealing temperature in ° C. forsample alloys -
FIG. 3c plots total elongation TE in % vs annealing temperature in ° C. forsample alloys -
FIG. 3d plots total elongation TE in % vs tensile strength TS in MPa forsample alloys -
FIG. 4a plots volume of ferrite in % and total elongation TE in % vs weight % Si for samples exhibiting TS of about 1180-1300 MPa -
FIG. 4a plots tensile strength TS in MPa and total elongation TE in % vs volume of ferrite in % samples exhibiting TS of about 1180-1300 MPa; -
FIG. 5a plots yield strength YS in MPa vs annealing temperature in ° C. forsample alloys -
FIG. 5b plots tensile strength TS in MPa vs annealing temperature in ° C. forsample alloys -
FIG. 5c plots total elongation TE in % vs annealing temperature in ° C. forsample alloys -
FIG. 5d plots total elongation TE in % vs tensile strength TS in MPa forsample alloys -
FIG. 6a plots yield strength YS in MPa vs annealing temperature in ° C. forsample alloys -
FIG. 6b plots tensile strength TS in MPa vs annealing temperature in ° C. forsample alloys -
FIG. 6c plots total elongation TE in % vs annealing temperature in ° C. forsample alloys -
FIG. 6d plots total elongation TE in % vs tensile strength TS in MPa forsample alloys -
FIG. 7a plots yield strength YS in MPa vs annealing temperature in ° C. forsample alloys -
FIG. 7b plots tensile strength TS in MPa vs annealing temperature in ° C. forsample alloys -
FIG. 7c plots total elongation TE in % vs annealing temperature in ° C. forsample alloys -
FIG. 7d plots total elongation TE in % vs tensile strength TS in MPa forsample alloys -
FIG. 8 plots the total elongation TE in % vs yield strength YS (squares) and tensile strength TS (diamonds) in MPa for all sample alloys; -
FIG. 9a plots yield strength YS in MPa vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C; -
FIG. 9b plots tensile strength TS in MPa vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C; -
FIG. 9c plots uniform elongation UEL in % vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C; -
FIG. 9d plots total elongation EL in % vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C; -
FIG. 10a plots yield strength YS in MPa vs post batch annealing temperature in ° C. forsample alloys -
FIG. 10b plots tensile strength TS in MPa vs post batch annealing temperature in ° C. forsample alloys -
FIG. 10c plots uniform elongation UEL in % vs post batch annealing temperature in ° C. forsample alloys -
FIG. 10d plots total elongation EL in % vs post batch annealing temperature in ° C. forsample alloys -
FIG. 11a plots the yield strength YS and tensile strength TS in MPa vs post batch annealing temperature for samples with a pre batch annealing TS of >1180 MPa; -
FIG. 11b plots the total elongation TE in % and hole expansion in % vs post batch annealing temperature in ° C. for samples with a pre batch annealing TS of >1180 Mpa; and -
FIG. 12 plots temperature in ° C. vs time in hours for a batch annealing cycle from a specific steel-making plant. - The carbon range of steel materials of the present invention is 0.1-0.3 wt %. The preferred range is about 0.15-0.25%. The minimum of 0.15% is required to achieve TRIP effect by retained austenite and strength. The maximum amount of 0.25% allows for better weldability. The manganese range of steel materials of the present invention is 1-3%, with 2-2.5% preferred. The minimum of 2% is necessary to achieve TS>980 MPa and the maximum amount of 2.5% is limited due to weldability and banded structure. The silicon range of steel materials of the present invention is 0.5-3.5%, with 1.5-2.5% preferred. The minimum of 1.5% is necessary to achieve the TRIP effect, while the maximum of 2.5% is limited due to weldability and Zn coatability. The aluminum range of steel materials of the present invention is 0.05-1.5%, with 0.05-1.0% preferred. The minimum of 0.5% is necessary to achieve the TRIP effect, while the maximum of 1% is limited by the required soak temperature at hot dip Zn coating line. Additionally the total amount of Mo and Cr should be 1% or less (i.e. Mo+Cr=0-1.0%) and the preferred level of Mo+Cr is 0.2-0.5% to achieve a TS>980 MPa. The remainder of the steel is iron with residuals at levels based on practical experiences.
- The process condition for forming the coated steel material is standard and there are no special requirements from the steel making stage to hot dip Zn coating. The properties of the hot dip Zn coated steel sheet are then improved by post batch annealing. The peak temperature of the post batch annealing should be between 150-650° C., more preferably between 150-450° C., most preferably between 200-400° C. The preferred minimum temperature of 200° C. is necessary to achieve better formability and the preferred maximum of 400° C. is to better avoid the possibility of degradation of the Zn coating.
- The ingots were produced by vacuum induction melting. The composition of the investigated steels is summarized in Table 1. The ingots have about 0.18-0.21% C at various ranges of Mn, Si, Al, Cr, Mo, Nb. The effect of each element on the mechanical properties and microstructure is discussed herein below.
-
TABLE 1 ID C Mn Si Nb Cr Mo Al P S N B 1 0.18 2.2 0.7 0.011 0.15 0.79 0.014 0.006 0.0056 2 0.18 2.2 0.3 0.010 0.16 1.23 0.010 0.006 0.0048 3 0.19 2.5 0.7 0.010 0.16 1.13 0.008 0.006 0.0044 4 0.19 2.5 0.3 0.010 0.15 1.51 0.008 0.006 0.0051 5 0.20 1.8 1.6 0.017 0.15 0.06 0.009 0.005 0.0061 6 0.21 1.8 2.0 0.018 0.16 0.07 0.008 0.005 0.0055 7 0.21 1.8 2.5 0.018 0.16 0.06 0.008 0.005 0.0056 8 0.20 1.5 1.2 0.020 0.30 0.64 0.005 0.005 0.0048 9 0.21 1.5 1.3 0.020 0.30 0.58 0.016 0.003 0.0041 10 0.21 1.5 1.3 0.021 0.30 0.58 0.016 0.003 0.0042 10 ppm 11 0.20 1.5 1.2 0.020 0.50 0.63 0.004 0.005 0.0047 12 0.20 1.5 1.2 0.020 0.15 0.64 0.004 0.005 0.0049 13 0.20 1.5 1.5 0.020 0.15 0.70 0.016 0.003 0.0043 14 0.20 1.5 2.0 0.020 0.16 0.73 0.016 0.003 0.0046 15 0.20 1.8 2.0 0.020 0.71 0.016 0.003 0.0049 16 0.20 2.3 1.0 0.15 0.05 0.01 0.003 0.0053 17 0.19 2.3 1.0 0.34 0.05 0.009 0.003 0.0058 18 0.20 2.5 1.0 0.04 0.009 0.003 0.0052 - All ingots were initially hot rolled to 20 mm thick plates. Then, the plates were reheated and hot rolled again with finishing temperature (FT) in the range of 840 to 890° C. and coiling temperature (CT) in the range of 500 to 650° C. to an average final hot band thickness of 3.8 mm. Table 2 summarizes the tensile properties of hot bands v/s FT and intended CT. The results demonstrate that CT is the most important factor that determines the microstructure and tensile properties of hot bands. The higher CT of 650° C. increases the fraction of martensite, although it is commonly believed to result in a lower strength product. Increasing Mn, Cr, and Mo increases the hardenability of the steel and promotes the formation of martensite. The addition of Al, a ferrite stabilizer, promotes the formation of ferrite resulting in a lower strength hot band. The addition of Si, another ferrite stabilizer like Al, promotes ferrite formation; however, at the same hot rolling condition, it increases steel strength due to solid solution hardening. When the metallurgical design is finalized, the effect of hot rolling conditions on the microstructure and strength of hot bands will be discussed, as well as the cold rollability. Both sides of the hot bands were mechanically ground to remove the decarburized surface layer, followed by 50% cold reduction to about 1.5 mm gauge.
-
TABLE 2 FT, aim ID ° C. CT, ° C. YS, MPa TS, MPa TE, % YPE, % YR 1 853 650 503 800 19.1 0.0 0.63 2 868 650 510 734 22.3 0.0 0.69 3 875 650 494 870 14.2 0.0 0.57 4 877 650 460 787 19.1 0.0 0.58 5 875 580 480 822 14.2 0.0 0.58 6 875 580 690 865 23.1 2.5 0.80 7 888 580 451 860 17.7 0.0 0.52 8 877 620 628 815 23.3 0.0 0.77 9 840 620 635 768 24.0 3.1 0.83 10 883 620 607 869 20.9 0.0 0.70 11 885 620 586 740 25.2 2.5 0.79 12 883 620 600 718 23.3 0.0 0.84 13 870 620 616 747 26.9 3.6 0.82 14 860 620 631 785 26.0 3.1 0.80 15 868 620 636 786 24.5 3.3 0.81 16 880 500 568 997 14.3 0.0 0.57 17 880 500 607 943 13.7 0.0 0.64 18 883 500 695 905 16.4 0.0 0.77 - Table 3 shows JIS-T tensile properties of selected full hard steels. Tensile strengths TS of about 1200 to about 1350 MPa (170-195 ksi) are observed.
-
TABLE 3 ID Gauge, mm YS, MPa TS, MPa UE, % TE, % 7 1.5 1163 1386 2.5 3.6 7 1.4 1180 1383 2.4 3.2 9 1.43 1058 1187 2.3 4.7 9 1.41 1068 1200 2.3 5.1 10 1.37 1121 1344 3.6 4.2 10 1.52 1102 1304 3.9 6.5 15 1.61 1095 1233 2.5 5.9 15 1.60 1102 1239 2.4 5.9 - Annealing simulations were run using CAS (Continuous Annealing Simulator) utilizing laboratory processed full hard steels and CL HDGL thermal cycles.
FIG. 1 plots temperature in ° C. vs time in seconds for a typical CL HDGL thermal cycle used in simulations by the present inventors. A wide range of annealing temperatures was investigated. Three thermocouples were used to ensure thermal homogeneity within the sample during reheating and cooling. - There were two sets of compositions for the investigation of Si content on tensile properties,
alloys 5/6/7 andalloys 12/13/14 with Si ranging from 1.2 to 2.5%.FIGS. 2a-2d and 3a-3d illustrate the effects of Si content and annealing temperature on the tensile properties of these two different sets of steels.FIG. 2a plots yield strength YS in MPa vs annealing temperature in ° C. forsample alloys FIG. 2b plots tensile strength TS in MPa vs annealing temperature in ° C. forsample alloys FIG. 2c plots total elongation TE in % vs annealing temperature in ° C. forsample alloys FIG. 2d plots total elongation TE in % vs tensile strength TS in MPa forsample alloys FIG. 3a plots yield strength YS in MPa vs annealing temperature in ° C. forsample alloys FIG. 3b plots tensile strength TS in MPa vs annealing temperature in ° C. forsample alloys FIG. 3c plots total elongation TE in % vs annealing temperature in ° C. forsample alloys FIG. 3d plots total elongation TE in % vs tensile strength TS in MPa forsample alloys FIGS. 2a-2d ) varies from 1.5 to 2.5% in a 0.2C-1.8Mn-0.15Mo-0.02Nb matrix, and the other set (FIGS. 3a-3d ) has 1.2 to 2.0% Si in a matrix comprised of 0.2C-1.5Mn-0.3Mo-0.7Al-0.02Nb. - As shown in
FIGS. 2a-2d , an increase in Si content from 1.5 to 2.0% significantly increases strength (yield strengty [YS], tensile strength [TS]) while marginally decreasing ductility. There is no significant strength enhancement as Si is further increased from 2.0 to 2.5%. A portion of the strength increase obtained upon increasing the Si content from 1.5 to 2.0% can be attributed to the solid solution hardening in these alloys; about 40-50 MPa for 0.5% Si addition. The increase in Si from 1.5 to 2.0 and 2.5% is also expected to increase Ac1 from 747° C. to 762° C. and 776° C. and Ac3 from 910° C. to 933° C. and 955° C., respectively, using Andrew's equations. In the 1.5% Si steel, the increase in anneal temperature from 800° C. to 825° C. and 850° C. is associated with a substantial increase in austenite formation. As the austenite content increases, it is diluted in carbon and is therefore less hardenable and more amenable to decomposition during the subsequent cooling. This behavior could explain the loss in strength with an increase in anneal temperature. As the Si content in the steel is increased from 1.5 to 2.0 and 2.5%, less austenite is formed at the same anneal temperature and it is also more hardenable. This could explain the relative stability in strength across annealing temperatures in the higher Si steels. - The strengths in the 2.0 and 2.5% Si bearing steels appear to be similar. That is, the higher solid solution strengthening in the 2.5% silicon steel is also associated with a relatively smaller volume fraction of martensite in comparison to the 2.0% Si bearing steel. The increase in Si from 1.5 to 2.0/2.5% is believed to enhance the hardenability of the steel as well. An additional potential reason for the difference in YS between 1.5Si and 2.0/2.5Si bearing steels may be attributable to the delay in the auto-tempering of martensite as the Si content in the steel is increased. The effect of Si among these alloys may be connected with other alloy effects.
- As shown in
FIGS. 3a-3d , the increase in Si from 1.2 to 2.0% in this base composition improves the balance between strength and ductility. The steels with a Si content of about 1.2-1.5% Si doesn't make TS>1180 MPa as the 0.7% Al addition substantially increasing the Ac1 and Ac3 temperatures. The steel with 2.0% Si demonstrates total elongation (TE)>16% at TS>1180 MPa. Since there is no significant amount of retained austenite that could result in substantial TRIP effect, the better ductility of the steel at higher Si content is attributed to Si solid solution hardening that allowed the attainment of the prescribed strength with less amount of martensite. It should be noted that the amount of Si for the best combination of strength-ductility depends on other alloying elements. Therefore, the Si amount should be optimized accordingly. In addition, the comparison between two sets of Si steels (FIGS. 2a-2d and 3a-3d ) indicates that there is a kind of synergetic effects of Si and Al addition even if other alloying elements are different. -
FIG. 4a shows the effect of Si addition on fraction of ferrite and TE in the samples having TS of about 1180-1300 MPa.FIG. 4a plots volume of ferrite in % and total elongation TE in % vs weight % Si for samples exhibiting TS of about 1180-1300 MPa.FIG. 4a plots tensile strength TS in MPa and total elongation TE in % vs volume of ferrite in % samples exhibiting TS of about 1180-1300 MPa. An increase in Si content reduces the volume fraction of martensite (increasing ferrite), and consequently improves ductility. The best combination of TS and TE (TS of 1200 MPa/TE of 16-18%) can be achieved at Vf (volume of ferrite) of about 70% inalloy 14 containing 2.0% Si. The ferrite fraction of about 70% is considerably higher compared to about 30-40% ferrite in prior art CR DP T1180 with TE of 10-13%. However, the amount of Si should be optimized according to the overall alloy combination, in favor of a larger annealing process window, better weldability, and acceptable coatability.FIG. 4b plots the TS and TE as a function of ferrite fraction in samples exhibiting TS of about 1180-1300 MPa. It should be noted that the ferrite amount was measured by image analysis employing only one field per sample. Therefore, the observed trend and not to the absolute volume fraction of ferrite as a function of silicon addition provides the most important information. - It is well known that Mn, Cr and Mo increase the hardenability of the steel. The reduction in the amount of austenite to ferrite/bainite decomposition results in a higher fraction of martensite. Comparing investigated steels, it is possible to assess the relative hardenability of Mn, Cr and Mo.
-
FIGS. 5a-5d show the effect of various Mo and Cr additions on the tensile properties of 0.2C-1.5Mn-1.2Si-0.65Al-0.02Nb containing steel.FIG. 5a plots yield strength YS in MPa vs annealing temperature in ° C. forsample alloys FIG. 5b plots tensile strength TS in MPa vs annealing temperature in ° C. forsample alloys FIG. 5c plots total elongation TE in % vs annealing temperature in ° C. forsample alloys FIG. 5d plots total elongation TE in % vs tensile strength TS in MPa forsample alloys -
FIG. 6a-6d compare the effects of 0.15Mo, 0.35Cr and increased (+0.2) Mn on the tensile properties of steels with a base composition of 0.2C-2.3Mn-1.0Si.FIG. 6a plots yield strength YS in MPa vs annealing temperature in ° C. forsample alloys FIG. 6b plots tensile strength TS in MPa vs annealing temperature in ° C. forsample alloys FIG. 6c plots total elongation TE in % vs annealing temperature in ° C. forsample alloys FIG. 6d plots total elongation TE in % vs tensile strength TS in MPa forsample alloys FIGS. 6a-6d , steels containing 0.15Mo and 0.35Cr have similar hardenability, and both had higher hardenability than +0.2Mn. All compositions display higher YS than steels based on 0.2C-1.5Mn-1.2Si-0.65Al-0.02Nb-X Mo/Cr since these compositions were fully austenitized in the investigated range of annealing temperatures which consequently promoted a partial bainite formation with lower amounts of ferrite. On the whole, none of the compared compositions demonstrated the desirable balance of TS and TE. - Effect of boron addition has been investigated by comparison of
alloys 9 & 10 containing a base composition of 0.2C-1.5Mn-1.3Si-0.6Al-0.3Mo-0.02Nb.FIGS. 7a-7d show the effect of B addition on the tensile properties of the steel.FIG. 7a plots yield strength YS in MPa vs annealing temperature in ° C. forsample alloys FIG. 7b plots tensile strength TS in MPa vs annealing temperature in ° C. forsample alloys FIG. 7c plots total elongation TE in % vs annealing temperature in ° C. forsample alloys FIG. 7d plots total elongation TE in % vs tensile strength TS in MPa forsample alloys - The present inventors' objective is to achieve as high as possible total elongation at TS>1180 MPa. In order to reach this goal, the fraction of ferrite in the microstructure should be maximized since the ferrite seems to be the main contributor to ductility, as shown in
FIG. 4b (even though the retained austenite contributes as well). However, higher ferrite fraction makes the steels softer due to its lower strength. Therefore, the ferrite and martensite should be hardened as much as possible to reach TS>1180 MPa in conjunction with superior ductility. In addition, the metallurgy has to be sound in terms of manufacturability on both the producer and customer fronts. The effect of Si addition on the solid solution hardening of ferrite has been well illustrated. Higher carbon content of 0.2% together with alloying elements that decrease the Ms temperature contributes to the strength of martensite. The addition of Nb results in finer grains of both ferrite and martensite. The addition of Mn is helpful to harden ferrite. However, it increases the strength of the hot bands as well by facilitating the formation of lower temperature transformation products in the as rolled structure. Mn, Cr and Mo should be optimized to achieve the proper amount of martensite in the final microstructure. The combination of C, Mn, Si and Al which affect Ac1 and Ac3 temperatures should be adjusted to ensure necessary austenite fraction during annealing within the typical industrial process window (about 750-850° C.). Mn, Si and Al should be minimized to improve the coatability of the strip as well. -
FIG. 8 shows the balance of TS-TE and YS-TE.FIG. 8 plots the total elongation TE in % vs yield strength YS (squares) and tensile strength TS (diamonds) in MPa for all sample alloys. The best combination is TS about 1180-1250 MPa, YS about 550-650 MPa, and TE about 15-18%. Based on the tensile results, the composition: 0.2C-1.5Mn-1.3Si-0.65Al-0.3Mo-0.02Nb is considered as the best combination of TS and TE. The hot band strength for this composition (CT 620° C.) is YS about 630 MPa, and TS about 800 MPa. The properties after annealing are: YS about 550 MPa, TS about 1250 MPa, and TE about 14-16%. - While the yield strength may be a bit low, it is believed that there is less chance of auto tempering of martensite due to the high alloy amount (leading to lower Ms) and this has an impact.
- The selected composition (0.2C-1.5Mn-1.3Si-0.65Al-0.3Mo-0.02Nb) raises two concerns for GA 1180 HF production; higher C than the desired maximum limit of 0.19% C and high alloy cost due to 0.3Mo addition. Therefore, a modified composition (0.18C-1.8Mn-1.5Si-0.65Al-0.02Nb-0.15Mo—shown in Table 4) has been investigated. The modified alloy substitutes 0.3% Si and 0.3% Mn for of 0.15% of the Mo. Table 5 shows the tensile properties of modified
alloy 7 which is very similar to alloy 8. The annealed tensile properties of modified alloy 8 are similar to those of alloy 8, as shown in Table 6. Therefore, this modification is considered as reasonable. -
TABLE 4 ID C Mn Si Nb Mo Al P S N Mod 0.17 1.81 1.55 0.02 0.15 0.65 0.017 0.005 0.0045 7 -
TABLE 5 Type FT CT YS TS UE TE YPE n YR ASTM 865 580 631 867 11.0 15.9 0.0 0.163 0.73 T -
TABLE 6 AT, C G, mm YS, MPa TS, MPa UE, % TE, % YPE, % N6-ue YR 775 1.54 487 1121 9.6 13.6 0.0 0.152 0.43 775 1.55 467 1069 8.9 12.6 0.0 0.166 0.44 800 1.55 521 1191 9.5 13.2 0.0 0.140 0.44 800 1.56 526 1195 9.2 13.0 0.0 0.138 0.44 825 1.58 543 1222 10.4 17.1 0.0 0.131 0.44 825 1.52 556 1246 10.3 14.1 0.0 0.130 0.45 850 1.57 544 1209 10.1 13.7 0.0 0.133 0.45 850 1.57 542 1201 9.6 13.3 0.0 0.132 0.45 - All measurements of selected samples show less than 10% HE which doesn't meet the desire target of 30% min. There is no necking and an obvious brittle fracture is observed in the tensile specimens. This can be correlated with poor HE performance. Metallurgically, the absence of tempering of the microstructure is contributing to the low hole expansion value and the low YS. Since all alloys have high alloying amounts the Ms temperature is decreased and auto-tempering is delayed during the post galvanneal cooling at the CL HDGL. An improvement in hole expansion and YS is necessary.
- Post batch annealing has been applied to the finished steel. The batch annealing cycle consisted of heating/cooling to tempering temperatures at a rate of 25° C./hr and isothermal tempering at the desired temperature for 5 hrs.
FIGS. 9a-9d show the effect of post batch annealing on tensile properties.FIG. 9a plots yield strength YS in MPa vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C.FIG. 9b plots tensile strength TS in MPa vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C.FIG. 9c plots uniform elongation UEL in % vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C.FIG. 9d plots total elongation EL in % vs post batch annealing temperature in ° C. for sample alloys containing 0.13 and 0.2% C. An increase in batch annealing temperature (BAT) significantly improves YS, but at a cost of UEL. It is worth mentioning that TE and TS slightly decrease. In addition, hole expansion improves to about 17% at BAT of 200° C., however it still not enough and significantly below the desired target of 30%. The results indicate the need for higher BAT such as 250° C. and higher. It should be noted that there may be non-uniform temperature issues using the batch anneal process (hot/cold spots during multi stack anneal). - In an attempt to avoid this, post tempering can be applied by in-line induction heating (for a shorter time than batch annealing). The samples having higher initial TS have been used in order to compensate for the loss in TS due to tempering.
FIGS. 10a-10d show the effect of short time induction annealing on the tensile properties of the steel. -
FIG. 10a plots yield strength YS in MPa vs post batch annealing temperature in ° C. forsample alloys FIG. 10b plots tensile strength TS in MPa vs post batch annealing temperature in ° C. forsample alloys FIG. 10c plots uniform elongation UEL in % vs post batch annealing temperature in ° C. forsample alloys FIG. 10d plots total elongation EL in % vs post batch annealing temperature in ° C. forsample alloys - Annealed panels of modified alloy 8 (AT=825C) have been isothermally post tempered at various temperatures for 6 hrs.
FIGS. 11a-11b show the effect of post tempering temperature on tensile properties and hole expansion.FIG. 11a plots the yield strength YS and tensile strength TS in MPa vs post batch annealing temperature for samples with a pre batch annealing TS of >1180 MPa.FIG. 11b plots the total elongation TE in % and hole expansion in % vs post batch annealing temperature in ° C. for samples with a pre batch annealing TS of >1180 MPa. YS is dramatically increased up to a tempering temperature of 350° C., then decreases. TS gradually reduced with increasing tempering temperature and TE remains relatively constant within the investigated temperature range. Hole expansion gradually improves as well. Based on these results, a further post tempering simulation has been performed using a batch annealing cycle from a specific plant, which is depicted inFIG. 12 .FIG. 12 plots temperature in ° C. vs time in hours for a batch annealing cycle from a specific steel-making plant. This cycle with an intended temperature of 260° C. (500° F.) has no temperature differential between hot and cold spots due to the long annealing time. Table 7 summarizes the JIS-T tensile properties and hole expansion data. This low temperature post batch annealing introduces non-uniformity of strength and ductility by about 20-30 MPa and about 1%, respectively. This non-uniformity is quite similar to the expected variation along the coil length. However, it requires a higher initial TS to ensure TS>1180 MPa after post batch annealing. The increase in Mn by 0.2% will provide an additional tensile strength of about 80 MPa to accommodate for the tensile drop upon post batch annealing. -
TABLE 7 Condition G, mm YS, MPa TS, MPa UE, % TE, % YPE, % n6-ue YR HE, % Cold Spot 1.55 875 1162 9.4 17.5 0.3 0.096 0.75 23 1.55 880 1162 9.2 15.7 0.2 0.096 0.76 Hot Spot 1.61 858 1137 8.8 15.5 0.9 0.100 0.76 23 1.59 857 1133 8.7 14.3 0.0 0.098 0.76 -
-
- UTS (MPa) refers to the ultimate tensile strength measured by tensile test in the longitudinal direction relative to the rolling direction,
- YS (MPa) refers to the yield strength measured by tensile test in the longitudinal direction relative to the rolling direction,
- TEI (%) refers to the total elongation.
UTS, YS and Tel can be measured following several tests. Tests used for examples 1 and 2 are according to JIS-T standard whereas tests used for example 3 are according to ISO standards. - HE (%) refers to the hole expansion. Such test can be performed with the help of a conical punch made of a cylindrical part which diameter is 45 mm, topped by a conical part. Such punch is being positioned under the steel sheet to test and which has been previously provided with a hole of an initial diameter Do of 10 mm. The conical punch is then being moved upwards into such hole and does enlarge it until a first traversing crack appears. The final diameter D of the hole is then being measured and the hole expansion is calculated using the following relationship:
- Another possibility to perform such test is to use a so called flat punch, made of a cylinder with a diameter of 75 mm, all other conditions being similar.
-
- Microstructures were observed using a SEM at the quarter thickness location, using 2% Nital etching and quantified by image analysis.
- Semi-finished products have been produced from steel castings. The chemical compositions of the semi-finished products, expressed in weight percent, are shown in Table 8 below. The rest of the steel compositions in Table 8 consists in iron and inevitable impurities resulting from the smelting.
-
TABLE 8 C Si Mn P S Cu Al Ti Nb N Cr Ni B Mo A 0.17 1.55 1.81 0.017 0.005 — 0.65 — 0.020 0.0045 — — — 0.15 B 0.15 0.7 2.6 0.015 0.003 — 0.8 — 0.010 0.0046 — — — 0.15 C 0.21 1.3 1.5 0.016 0.003 — 0.58 — 0.021 0.0042 — — 10 0.30 D 0.21 1.3 1.5 0.016 0.003 — 0.58 — 0.020 0.0041 — — — 0.30 Table 1: Chemical composition (wt %, B in ppm). - Ingots of composition A to D were initially hot rolled to 20 mm thick plates. Then, the plates were reheated and hot-rolled again down to 3.8 mm. The hot rolled steel plates were then cold rolled and annealed. The process parameters undergone are shown hereunder:
-
- Finishing rolling temperature: 875° C.
- Coiling temperature: 580° C.
- Cold rolling reduction rate: around 50%
- Soaking temperature during annealing: 825° C.
- Soaking duration during annealing: 150 s.
- After annealing, coating by hot dip galvanizing in a bath of molten zinc was simulated by heating the steel sheets at a temperature of 460° C., followed by a galvannealing treatment at 575° C.
- The microstructure of steel sheets A to D contains ferrite (including bainitic ferrite), martensite and MA islands in surface proportion given in the Table 9 below, before being submitted to post tempering by two different ways. Such surface fractions are unchanged after post tempering which is only modifying the carbon concentration inside those phases.
-
TABLE 9 Table 9: Microstructures (surface %) Ferrite Martensite + MA islands A 67 43 B 42 58 C 56 44 D 58 42 - Post tempering of a set of steel sheets A was performed by heating such steels as a coil in a batch annealing furnace. The heating and cooling rates before and after tempering were done at a rate of 25° C./h isothermal tempering was done at the desired temperature for 5 hours.
- It can be seen from Table 10 that the post tempering treatment decreases slightly the tensile strength and the total elongation but increases notably the yield strength and hole expansion properties. In fact the hole expansion of sample A without tempering was not measurable as the steel was too brittle.
-
TABLE 10 Table 10: Mechanical properties - nm: not measured Thickness UTS YS Tel HE (mm) (MPa) (MPa) (%) (%) A (without tempering) 1.41 1227 555 15.6 nm A - 200° C. 1.36 1195 802 13.9 17 - Post tempering of a set of steel sheets B to D was performed by induction heating the steel sheets to reach the desired temperature, which was maintained during the times specified in Table 11.
-
TABLE 11 Table 4: Mechanical properties - HE: conical punch Thickness UTS YS Tel HE (mm) (MPa) (MPa) (%) (%) B (without tempering) 1.59 1319 645 14.2 nm B - 300° C. - 30 sec 1.56 1240 943 13.6 22.7 B - 400° C. - 30 sec 1.53 1141 969 10.9 33.7 C (without tempering) 1.52 1308 605 14.3 nm C - 300° C. - 30 sec 1.54 1221 784 15.3 16.8 C - 400° C. - 30 sec 1.54 1149 896 13.4 32.0 D (without tempering) 1.42 1235 564 14.8 nm D - 250° C. - 30 sec 1.37 1158 576 14.8 12.2 D - 300° C. - 30 sec 1.42 1159 729 15.2 17.5 - It can be seen from Table 11 that the post tempering treatment decreases slightly the tensile strength but increases notably the yield strength and hole expansion properties. The hole expansion of samples B, C and D without tempering was not measurable as the steel was too brittle
- Semi-finished products have been produced from steel castings. The chemical composition of the semi-finished products, expressed in weight percent, is shown in Table 12 below. The rest of the steel composition in Table 5 consists in iron and inevitable impurities resulting from the smelting.
-
TABLE 12 C Si Mn P S Cu Al Ti Nb V N Cr Ni B Mo E 0.18 1.52 1.99 0.013 0.005 0.04 0.62 0.005 0.007 0.007 0.0065 0.04 0.01 3 0.15 Table 5: Chemical composition (wt %, B in ppm). - Ingot of
composition 5 was initially hot rolled to 20 mm thick plates. Then, the plates were reheated and hot-rolled again down to 3.8 mm. The hot rolled steel plates were then cold rolled and annealed. The process parameters undergone are shown hereunder: -
- Finishing rolling temperature: 930° C.
- Coiling temperature: 680° C.
- Cold rolling reduction rate: around 50%
- Soaking temperature during annealing: 825° C.
- Soaking duration during annealing: 150 s.
After annealing, coating by hot dip galvanizing in a bath of molten zinc was performed in a bath at a temperature of 460° C., followed by a galvannealing treatment.
- The microstructure of steel sheets E contains ferrite (including bainitic ferrite), martensite and MA islands in surface proportion according to the invention, before being submitted to post tempering by batch annealing. Such surface fractions are unchanged after post tempering which is only modifying the carbon concentration inside those phases.
- Post tempering of a set of
steel sheets 5 was performed by heating such steels as a coil in a batch annealing furnace. Isothermal tempering was done at the desired temperature for 5 hours. Temper rolling was then performed with 0.3% elongation. -
TABLE 13 Table 6: Mechanical properties - nm: not measured - H: conical punch Thickness UTS YS Tel HE (mm) (MPa) (MPa) (%) (%) E (without tempering) 1.4 1180 560 10 nm E - 290° C. 1.4 1150 760 15 18 - It can be seen from Table 13 that the post tempering treatment decreases slightly the tensile strength and the total elongation but increases notably the yield strength and hole expansion properties. In fact the hole expansion of
sample 5 without tempering was not measurable as the steel was too brittle. - After such post tempering, the galvannealed coatings were not damaged and their iron content was 11% without significant increase due to post tempering.
- Semi-finished products have been produced from a steel casting. The chemical composition of the semi-finished products, expressed in weight percent, is shown in Table 14 below. The rest of the steel composition in Table 14 consists in iron and inevitable impurities resulting from the smelting.
-
TABLE 14 C Si Mn P S Cu Al Ti Nb N Cr Ni Mo F 0.22 0.11 1.73 0.02 0.001 0.04 1.49 0.01 0.01 0.01 0.02 0.02 0.13 Table 7: Chemical composition (wt %). - Ingots of composition F were initially hot rolled to 4 mm thick plates. The hot rolled steel plates were then cold rolled and annealed. The process parameters undergone are shown hereunder:
-
- Finishing rolling temperature: 900° C.
- Coiling temperature: 550° C.
- Cold rolling reduction rate: around 50%
- Soaking temperature during annealing: 850° C.
- Soaking duration during annealing: 100 s
- After annealing, coating by hot dip galvanizing in a bath of molten zinc was performed with an immersion temperature of 455° C., followed by a galvannealing treatment at 540° C.
- The microstructure of steel sheet F contains 71% of ferrite (including bainitic ferrite), 20% of martensite and 9% of austenite before being submitted to post tempering by two different ways. Such surface fractions are unchanged after post tempering which is only modifying the carbon concentration inside those phases.
- Post tempering of a first set of steel sheets E was performed by heating such steels as a coil in a batch annealing furnace. Isothermal tempering was done at the desired temperature for 8 hours.
-
TABLE 15 Table 15: Mechanical properties - HE: flat punch Thickness UTS YS Tel HE (mm) (MPa) (MPa) (%) (%) E (without tempering) 2 802 486 23.9 17.9 E - 150° C. 2 810 488 25.7 20.0 E - 200° C. 2 805 500 25.8 21.1 E - 250° C. 2 766 544 23.2 25.3 E - 400° C. 2 750 593 18.7 25.3 E - 500° C. 2 706 541 19.8 22.1 - Hole expansion was measured by flat punch which is a tougher test than conical punch and gave lower values than hereunder. However, trends are similar whatever the test used.
- It can be seen from Table 15 that the post tempering treatment decreases slightly the tensile strength but increases notably the yield strength and hole expansion properties up to 500° C.
- After such post tempering, the galvannealed coatings were not damaged and their iron content was 10% without significant increase due to post tempering.
- Post tempering of a second set of steel sheets E was performed by induction heating the steel sheets to reach the desired temperature, which was maintained during the times specified in table 16.
-
TABLE 16 Table 16: Mechanical properties - HE: conical punch Thickness UTS YS Tel HE (mm) (MPa) (MPa) (%) (%) E (without tempering) 2 802 486 23.9 22.1 E - 200° C. - 2 min 2 806 487 24.6 24.7 E - 400° C. - 2 min 2 795 493 24.1 24.7 E - 400° C. - 10 min 2 751 558 24.5 30.5 E - 500° C. - 2 min 2 802 508 24.1 26.3 E - 500° C. - 10 min 2 779 515 18.9 30 - It can be seen from Table 9 that the post tempering treatment decreases slightly the tensile strength but increases notably the yield strength and hole expansion properties.
- After such post tempering, the galvannealed coatings were not damaged and their iron content was 10% without significant increase due to post tempering.
- Table 17 shows the properties of a zinc coated steel sheet as coated and after post annealing at 288° C. As can be seen the annealing has increased the yield strength by at least 30% compared with the as coated sheet, preferably 40%. The annealing has also increased the total elongation by at least 25% compared with the as coated sheet, preferably at least 40%. Finally, the annealing has increased the hole expansion by at least 80% compared with the as coated sheet, preferably 95%.
-
TABLE 17 Sample Property As coated PBA + TR % Improvement 5520046 YS, Mpa 550-580 750-850 41.6 TS, Mpa 1160-1220 1100-1150 — TE, % 10-12.5 15-17 42.2 HE, % <10 18-21 95.0 Bend, r/t >4 2.2-2.4 — 5520047 YS, Mpa 550-595 770-850 41.5 TS, Mpa 1170-1240 1110-1170 — TE, % 10-12.5 13.5-15.5 28.9 HE, % <10 16-20 80.0 Bend, r/t >4 2.2-2.4 — 5520380 YS, Mpa 550-580 750-820 38.9 TS, Mpa 1150-1215 1140-1175 — TE, % 6.0-12 13-15.5 58.3 HE, % <10 21-25 130.0 Bend, r/t >4 2-2.5 — 5520379 YS, Mpa 540-580 700-820 35.7 TS, Mpa 1150-1210 1110-1180 — TE, % 7.5-13 12-15.5 34.1 HE, % <10 15-21 80.0 Bend, r/t >4 2.3-2.5 — - The steel sheets according to the invention will be beneficially used for the manufacture of structural or safety parts in the automobile industry. It is to be understood that the disclosure set forth herein is presented in the form of detailed embodiments described for the purpose of making a full and complete disclosure of the present invention, and that such details are not to be interpreted as limiting the true scope of this invention as set forth and defined in the appended claims.
Claims (11)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/552,485 US20180044750A1 (en) | 2015-02-25 | 2016-02-24 | Post Annealed High Tensile Strength Coated Steel Sheet having Improved Yield Strength and Hole Expansion |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201562120426P | 2015-02-25 | 2015-02-25 | |
US15/552,485 US20180044750A1 (en) | 2015-02-25 | 2016-02-24 | Post Annealed High Tensile Strength Coated Steel Sheet having Improved Yield Strength and Hole Expansion |
PCT/US2016/019428 WO2016138185A1 (en) | 2015-02-25 | 2016-02-24 | Post annealed high tensile strength coated steel sheet having improved yield strength and hole expansion |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2016/019428 A-371-Of-International WO2016138185A1 (en) | 2015-02-25 | 2016-02-24 | Post annealed high tensile strength coated steel sheet having improved yield strength and hole expansion |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US17/083,451 Continuation US11661637B2 (en) | 2015-02-25 | 2020-10-29 | Method for forming a cold rolled, coated and post batch annealed steel sheet |
Publications (1)
Publication Number | Publication Date |
---|---|
US20180044750A1 true US20180044750A1 (en) | 2018-02-15 |
Family
ID=55527652
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/552,485 Abandoned US20180044750A1 (en) | 2015-02-25 | 2016-02-24 | Post Annealed High Tensile Strength Coated Steel Sheet having Improved Yield Strength and Hole Expansion |
US17/083,451 Active 2036-03-23 US11661637B2 (en) | 2015-02-25 | 2020-10-29 | Method for forming a cold rolled, coated and post batch annealed steel sheet |
US18/135,962 Pending US20230257846A1 (en) | 2015-02-25 | 2023-04-18 | Cold rolled, coated and post batch annealed steel sheet |
Family Applications After (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US17/083,451 Active 2036-03-23 US11661637B2 (en) | 2015-02-25 | 2020-10-29 | Method for forming a cold rolled, coated and post batch annealed steel sheet |
US18/135,962 Pending US20230257846A1 (en) | 2015-02-25 | 2023-04-18 | Cold rolled, coated and post batch annealed steel sheet |
Country Status (11)
Country | Link |
---|---|
US (3) | US20180044750A1 (en) |
EP (1) | EP3262205A1 (en) |
JP (2) | JP2018510263A (en) |
KR (2) | KR20190134842A (en) |
CN (1) | CN107429376B (en) |
BR (1) | BR112017016683A2 (en) |
CA (1) | CA2975149C (en) |
MX (1) | MX2017010788A (en) |
RU (1) | RU2705741C2 (en) |
UA (1) | UA120199C2 (en) |
WO (1) | WO2016138185A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114107796A (en) * | 2020-08-31 | 2022-03-01 | 宝山钢铁股份有限公司 | 1180 MPa-grade high-plasticity high-hole-expansion steel and manufacturing method thereof |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE545209C2 (en) * | 2020-12-23 | 2023-05-23 | Voestalpine Stahl Gmbh | Coiling temperature influenced cold rolled strip or steel |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20140242414A1 (en) * | 2011-07-29 | 2014-08-28 | Nippon Steel & Sumitomo Metal Corporation | High-strength steel sheet and high-strength galvanized steel sheet excellent in shape fixability, and manufacturing method thereof |
WO2015015239A1 (en) * | 2013-08-02 | 2015-02-05 | ArcelorMittal Investigación y Desarrollo, S.L. | Cold rolled, coated and post tempered steel sheet and method of manufacturing thereof |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4235030B2 (en) | 2003-05-21 | 2009-03-04 | 新日本製鐵株式会社 | High-strength cold-rolled steel sheet and high-strength surface-treated steel sheet having excellent local formability and a tensile strength of 780 MPa or more with suppressed increase in hardness of the weld |
JP4473587B2 (en) * | 2004-01-14 | 2010-06-02 | 新日本製鐵株式会社 | Hot-dip galvanized high-strength steel sheet with excellent plating adhesion and hole expandability and its manufacturing method |
KR100990772B1 (en) | 2005-12-28 | 2010-10-29 | 가부시키가이샤 고베 세이코쇼 | Ultrahigh-strength steel sheet |
JP5434960B2 (en) | 2010-05-31 | 2014-03-05 | Jfeスチール株式会社 | High-strength hot-dip galvanized steel sheet excellent in bendability and weldability and method for producing the same |
JP5765092B2 (en) * | 2010-07-15 | 2015-08-19 | Jfeスチール株式会社 | High yield ratio high-strength hot-dip galvanized steel sheet with excellent ductility and hole expansibility and method for producing the same |
JP5298114B2 (en) * | 2010-12-27 | 2013-09-25 | 株式会社神戸製鋼所 | High-strength cold-rolled steel sheet with excellent coating film adhesion and workability, and method for producing the same |
WO2012153009A1 (en) | 2011-05-12 | 2012-11-15 | Arcelormittal Investigación Y Desarrollo Sl | Method for the production of very-high-strength martensitic steel and sheet thus obtained |
US20130076187A1 (en) | 2011-09-16 | 2013-03-28 | Adam Daniel Flaster | 5-phase alternating current induction motor and inverter system |
JP2013237877A (en) * | 2012-05-11 | 2013-11-28 | Jfe Steel Corp | High yield ratio type high strength steel sheet, high yield ratio type high strength cold rolled steel sheet, high yield ratio type high strength galvanized steel sheet, high yield ratio type high strength hot dip galvanized steel sheet, high yield ratio type high strength hot dip galvannealed steel sheet, method for producing high yield ratio type high strength cold rolled steel sheet, method for producing high yield ratio type high strength hot dip galvanized steel sheet and method for producing high yield ratio type high strength hot dip galvannealed steel sheet |
JP2013241636A (en) * | 2012-05-18 | 2013-12-05 | Jfe Steel Corp | Low yield ratio type high strength hot dip galvanized steel sheet, low yield ratio type high strength alloying hot dip galvannealed steel sheet, method for manufacturing low yield ratio type high strength hot dip galvanized steel sheet, and method for manufacturing low yield ratio type high strength alloying hot dip galvannealed steel sheet |
-
2016
- 2016-02-24 CN CN201680011461.6A patent/CN107429376B/en active Active
- 2016-02-24 WO PCT/US2016/019428 patent/WO2016138185A1/en active Application Filing
- 2016-02-24 MX MX2017010788A patent/MX2017010788A/en unknown
- 2016-02-24 EP EP16709873.0A patent/EP3262205A1/en not_active Withdrawn
- 2016-02-24 RU RU2017133036A patent/RU2705741C2/en active
- 2016-02-24 KR KR1020197035128A patent/KR20190134842A/en not_active Application Discontinuation
- 2016-02-24 KR KR1020177024318A patent/KR20170110650A/en active Application Filing
- 2016-02-24 JP JP2017544892A patent/JP2018510263A/en active Pending
- 2016-02-24 UA UAA201709316A patent/UA120199C2/en unknown
- 2016-02-24 US US15/552,485 patent/US20180044750A1/en not_active Abandoned
- 2016-02-24 BR BR112017016683-6A patent/BR112017016683A2/en not_active Application Discontinuation
- 2016-02-24 CA CA2975149A patent/CA2975149C/en active Active
-
2020
- 2020-05-07 JP JP2020081755A patent/JP2020153016A/en active Pending
- 2020-10-29 US US17/083,451 patent/US11661637B2/en active Active
-
2023
- 2023-04-18 US US18/135,962 patent/US20230257846A1/en active Pending
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20140242414A1 (en) * | 2011-07-29 | 2014-08-28 | Nippon Steel & Sumitomo Metal Corporation | High-strength steel sheet and high-strength galvanized steel sheet excellent in shape fixability, and manufacturing method thereof |
WO2015015239A1 (en) * | 2013-08-02 | 2015-02-05 | ArcelorMittal Investigación y Desarrollo, S.L. | Cold rolled, coated and post tempered steel sheet and method of manufacturing thereof |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114107796A (en) * | 2020-08-31 | 2022-03-01 | 宝山钢铁股份有限公司 | 1180 MPa-grade high-plasticity high-hole-expansion steel and manufacturing method thereof |
Also Published As
Publication number | Publication date |
---|---|
KR20190134842A (en) | 2019-12-04 |
US20230257846A1 (en) | 2023-08-17 |
KR20170110650A (en) | 2017-10-11 |
EP3262205A1 (en) | 2018-01-03 |
RU2705741C2 (en) | 2019-11-11 |
MX2017010788A (en) | 2018-04-30 |
BR112017016683A2 (en) | 2018-04-10 |
UA120199C2 (en) | 2019-10-25 |
CA2975149C (en) | 2019-04-30 |
CA2975149A1 (en) | 2016-09-01 |
JP2020153016A (en) | 2020-09-24 |
CN107429376B (en) | 2020-10-09 |
RU2017133036A3 (en) | 2019-03-25 |
US20210123114A1 (en) | 2021-04-29 |
US11661637B2 (en) | 2023-05-30 |
RU2017133036A (en) | 2019-03-25 |
WO2016138185A1 (en) | 2016-09-01 |
JP2018510263A (en) | 2018-04-12 |
CN107429376A (en) | 2017-12-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
KR101858868B1 (en) | Plated steel sheets for hot press forming having excellent impact toughness, hot press formed parts, and methods of manufacturing the same | |
JP4860784B2 (en) | High strength steel plate with excellent formability and method for producing the same | |
JP5971434B2 (en) | High-strength hot-dip galvanized steel sheet excellent in stretch flangeability, in-plane stability and bendability of stretch flangeability, and manufacturing method thereof | |
JP2020114946A (en) | Method for producing high strength steel sheet having improved strength, ductility and formability | |
CN110709183B (en) | Steel sheet for hot press-formed member having excellent hydrogen-induced delayed fracture resistance and method for producing same | |
US20230257846A1 (en) | Cold rolled, coated and post batch annealed steel sheet | |
JP2017002384A (en) | Steel plate superior in spot weld zone fracture resistance characteristics and production method thereof | |
JP2020045573A (en) | Method for manufacturing high-strength coated steel sheet having improved strength, ductility and formability | |
JPWO2013118679A1 (en) | High-strength cold-rolled steel sheet and manufacturing method thereof | |
JP7082963B2 (en) | Manufacturing method of high-strength coated steel sheet with improved strength and formability and obtained steel sheet | |
KR20150023566A (en) | Steel, sheet steel product and process for producing a sheet steel product | |
JP2017514989A (en) | Method for producing cold rolled flat steel product with high yield strength and cold rolled flat steel product | |
KR20160057457A (en) | Steel for hot forming | |
US11198928B2 (en) | Method for producing high silicon dual phase steels with improved ductility | |
WO2017169870A1 (en) | Thin steel plate and plated steel plate, hot rolled steel plate manufacturing method, cold rolled full hard steel plate manufacturing method, heat-treated plate manufacturing method, thin steel plate manufacturing method and plated steel plate manufacturing method | |
EP3656879A2 (en) | Method for manufacturing a high-strength steel sheet and sheet obtained by the method | |
JP2019512600A (en) | Hot-dip galvanized steel sheet excellent in bake hardenability and aging resistance and method for producing the same | |
JP4265152B2 (en) | High-tensile cold-rolled steel sheet with excellent elongation and stretch flangeability and method for producing the same | |
US7699947B2 (en) | Ultrahigh strength hot-rolled steel and method of producing bands | |
JP4333352B2 (en) | Method for producing high-strength cold-rolled steel sheet excellent in ductility and stretch flangeability | |
JP4492105B2 (en) | Manufacturing method of high-strength cold-rolled steel sheet with excellent stretch flangeability | |
EP3305932B1 (en) | High strength steel sheet and method for producing same | |
JP6541504B2 (en) | High strength high ductility steel sheet excellent in production stability, method for producing the same, and cold rolled base sheet used for production of high strength high ductility steel sheet | |
KR20130046935A (en) | Cold-rolled steel sheet and method of manufacturing the cold-rolled steel sheet | |
KR20190077191A (en) | Cold rolled steel sheet and hot dip zinc-based plated steel sheet having excellent bake hardenability and plating adhesion, and method for manufaturing the same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: ARCELORMITTAL, LUXEMBOURG Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:JO JUN, HYUN;REEL/FRAME:044846/0027 Effective date: 20170922 |
|
AS | Assignment |
Owner name: ARCELORMITTAL, LUXEMBOURG Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:JO JUN, HYUN;REEL/FRAME:044958/0529 Effective date: 20170922 |
|
AS | Assignment |
Owner name: ARCELORMITTAL, LUXEMBOURG Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:JUN, HYUN JO;REEL/FRAME:045081/0468 Effective date: 20170922 |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: FINAL REJECTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: FINAL REJECTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |