[go: up one dir, main page]

EP4464802A1 - Tôle en acier galvanisée par immersion à chaud, et procédé de fabrication de celle-ci - Google Patents

Tôle en acier galvanisée par immersion à chaud, et procédé de fabrication de celle-ci Download PDF

Info

Publication number
EP4464802A1
EP4464802A1 EP22920482.1A EP22920482A EP4464802A1 EP 4464802 A1 EP4464802 A1 EP 4464802A1 EP 22920482 A EP22920482 A EP 22920482A EP 4464802 A1 EP4464802 A1 EP 4464802A1
Authority
EP
European Patent Office
Prior art keywords
steel sheet
less
dip galvanized
hot dip
interface
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22920482.1A
Other languages
German (de)
English (en)
Inventor
Takafumi Yokoyama
Chisato Yoshinaga
Takuya Kuwayama
Kengo Takeda
Takuya MITSUNOBU
Seiji Furusako
Tatsuya Obuchi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Nippon Steel Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nippon Steel Corp filed Critical Nippon Steel Corp
Publication of EP4464802A1 publication Critical patent/EP4464802A1/fr
Pending legal-status Critical Current

Links

Images

Classifications

    • 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
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0273—Final recrystallisation annealing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0278—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular surface 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
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
    • C21D8/0426—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
    • C21D8/0436—Cold rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0447—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment
    • C21D8/0463—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment following hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • 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
    • 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
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • 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
    • C22C38/10—Ferrous alloys, e.g. steel alloys containing cobalt
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
    • C23C2/0224—Two or more thermal pretreatments
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/024—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by cleaning or etching
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/06—Zinc or cadmium or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/14—Removing excess of molten coatings; Controlling or regulating the coating thickness
    • C23C2/16—Removing excess of molten coatings; Controlling or regulating the coating thickness using fluids under pressure, e.g. air knives
    • C23C2/18—Removing excess of molten coatings from elongated material
    • C23C2/20—Strips; Plates
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/26—After-treatment
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/26—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
    • C21D2211/001—Austenite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/002—Bainite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/003—Cementite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/008—Martensite
    • C—CHEMISTRY; METALLURGY
    • 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
    • C21D2211/009—Pearlite

Definitions

  • the present invention relates to a hot dip galvanized steel sheet and a method for producing the same, more particularly relates to a high strength hot dip galvanized steel sheet mainly used as steel sheet for automotive use and a method for producing the same.
  • a high strength steel sheet is being increasingly applied so as to lighten the weight of vehicle bodies and secure collision safety.
  • a high strength steel sheet with a tensile strength of 980 MPa or more.
  • a high strength hot dip galvanized steel sheet which is hot dip galvanized at its surface is sought for portions where rust resistance is demanded.
  • the steel sheet used for automobile members require not only strength, but also press-formability and weldability and other types of processability required for forming parts. Specifically, from the viewpoint of press-formability, a steel sheet is being asked to provide excellent elongation (total elongation EL at tensile test) and stretch flangeability (hole expansion ratio: ⁇ ).
  • TRIP transformation induced plasticity
  • PTLs 1 to 3 disclose high strength TRIP steel sheet with percentages of microstructure components controlled to predetermined ranges and improved in elongation and hole expansion ratio.
  • PTL 4 describes a high strength steel sheet having a predetermined chemical composition, comprising ferrite with an average crystal grain size of 2 ⁇ m or less in a volume percentage of 15% or less, retained austenite with an average crystal grain size of 2 ⁇ m or less in a volume percentage of 2 to 15%, martensite with an average crystal grain size of 3 ⁇ m or less in a volume percentage of 10% or less, and a balance of bainite and tempered martensite with an average crystal grain size of 6 ⁇ m or less, and containing an average of 10 or more cementite particles with a grain size of 0.04 ⁇ m or more in the bainite and tempered martensite grains and described that the high strength steel sheet has a 1180 MPa or more tensile strength and has high elongation and hole expandability and an accompanying excellent bendability.
  • PTL 5 discloses TRIP steel sheet improved in stretch flangeability by limiting the area ratio of blocky (low aspect ratio) retained austenite.
  • PTL 6 discloses high strength TRIP steel sheet large in work hardening in initial shaping and having excellent shape freezeability and workability by control of the amount of dissolved Si and amount of dissolved Mn contained in the retained austenite to predetermined values or more.
  • LME liquid metal embrittlement
  • PTL 10 discloses a method of production of a hot dip galvanized steel sheet excellent in LME cracking resistance characterized by controlling the atmosphere at the time of heating and annealing at the hot dip galvanization line.
  • an object of the present invention is to provide a hot dip galvanized steel sheet excellent in press-formability and LME cracking resistance of spot welds and a method for producing the same.
  • the inventors engaged in intensive studies for achieving the above object and as a result discovered that the sensitivity of spot welds to LME cracking in a hot dip galvanized steel sheet is remarkably improved in the following cases.
  • Recessed parts present at the interface of the base steel sheet and hot dip galvanized layer (below, also simply referred to as the "steel sheet/plating interface") easily accumulate Zn melted by the input heat at the time of spot welding and become parts where stress concentrates, and therefore it is believed that easily become starting points of LME cracking.
  • it is not the recessed/projecting parts of the hot dip galvanized steel sheet, but the recessed parts of the steel sheet/plating interface that are important. This feature fundamentally differs from the generally measured steel sheet roughness. Specifically, the inventors discovered that if the number density of recessed parts with depths at the steel sheet/plating interface of more than 2 ⁇ m is 2.0/100 ⁇ m or less per interface length, a remarkable effect of improvement is obtained.
  • the Al rich layer present at the steel sheet/plating interface inhibits the penetration of molten Zn into the base steel sheet. Further, the inventors discovered that this effect becomes larger the higher the Al concentration in the Al rich layer. Specifically, the inventors discovered that if the maximum value of the Al concentration of the Al rich layer present at the steel sheet/plating interface is 2.0 mass% or more when using a high frequency glow discharge optical emission spectrometer (GDS) to measure the Al concentration from the surface of the hot dip galvanized steel sheet down in the depth direction, a remarkable effect of improvement is obtained.
  • GDS glow discharge optical emission spectrometer
  • the inventors discovered that if the Si s /Si b at the base steel sheet right under the steel sheet/plating interface is 0.90 or less when using a high frequency glow discharge optical emission spectrometer (GDS) to measure the emission intensity of Si from the surface of the hot dip galvanized steel sheet down in the depth direction, a remarkable effect of improvement is obtained.
  • GDS glow discharge optical emission spectrometer
  • C carbon
  • the C content is 0.15% or more.
  • the C content may also be 0.16% or more, 0.18% or more, or 0.20% or more.
  • the C content is 0.30% or less.
  • the C content may also be 0.28% or less, 0.27% or less, or 0.25% or less.
  • Si is an element suppressing the formation of iron carbides and contributing to improvement of the strength and shapeability.
  • the Si content is 0.30% or more.
  • the Si content may also be 0.40% or more, 0.50% or more, 0.51% or more, 0.52% or more, 0.55% or more, 0.60% or more, or 0.70% or more.
  • the Si content is 2.50% or less.
  • the Si content is preferably lower. Specifically, 2.00% or less is preferable, and 1.50% or less is more preferable. In particular, if limiting the Si content to 1.20% or less, it is possible to obtain particularly excellent LME cracking sensitivity resistance.
  • Mn manganese
  • Mn content is a powerful austenite stabilizing element and an element effective for raising the strength of steel sheet.
  • the Mn content is 1.40% or more.
  • the Mn content may be 1.50% or more, 1.70% or more, or 2.00% or more.
  • excessive addition sometimes causes deterioration of the press-formability and other workability and the weldability and furthermore the low temperature toughness. Therefore, the Mn content is 3.49% or less.
  • the Mn content may also be 3.20% or less, 3.00% or less, or 2.90% or less.
  • P phosphorus
  • the P content is limited to 0.050% or less.
  • the P content is preferably 0.045% or less, 0.035% or less, or 0.020% or less.
  • the P content may also be 0%, but to make the P content decrease to an extreme degree, the dephosphorization cost increases, therefore from the viewpoint of economy, the lower limit is preferably 0.001%.
  • S sulfur
  • the S content is preferably 0.0050% or less, 0.0040% or less, or 0.0030% or less.
  • the S content may also be 0%, but to make the S content decrease to an extreme degree, the desulfurization cost increases, therefore from the viewpoint of economy, the lower limit is preferably 0.0001%.
  • Al (aluminum) is added in at least 0.001% for deoxidation of the steel.
  • the Al content may also be 0.005% or more, 0.01% or more, 0.02% or more, 0.05% or more, or 0.10% or more.
  • the Al content is given an upper limit of 1.50%.
  • the Al content may also be 1.40% or less, 1.20% or less, or 1.00% or less.
  • Al has the effect of suppressing the formation of iron carbides to thereby make the retained austenite increase. If desiring to obtain this effect, Al has to be added in 0.30% or more.
  • the Al content may also be 0.50% or more or 0.70% or more.
  • N nitrogen
  • the N content is an element contained as an impurity and forms coarse nitrides in the steel to cause deterioration of the bendability and hole expandability if the content is large. Therefore, the N content is limited to 0.0100% or less.
  • the N content is preferably 0.0080% or less, 0.0060% or less, or 0.0050% or less.
  • the N content may also be 0%, but to make the N content decrease to an extreme degree, the denitridation cost increases, therefore from the viewpoint of economy, the lower limit is preferably 0.0001%.
  • O oxygen
  • the O content is an element contained as an impurity and forms coarse oxides in the steel to cause deterioration of the bendability and hole expandability if the content is large. Therefore, the O content is limited to 0.0100% or less.
  • the O content is preferably 0.0080% or less, 0.0060% or less, or 0.0050% or less.
  • the O content may also be 0%, but from the viewpoint of production costs, the lower limit is preferably 0.0001%.
  • the basic chemical composition of the base steel sheet according to an embodiment of the present invention and the slab used for its production is as explained above. Furthermore, the base steel sheet and slab may contain the following optional elements in accordance with need.
  • the lower limit of content in the case of not including any optional elements is 0%.
  • Cr chromium
  • Mo mobdenum
  • Cu copper
  • Ni nickel
  • Co cobalt
  • W tungsten
  • Sn tin
  • Sb antimony
  • Nb niobium
  • Ti titanium
  • V vanadium
  • B boron
  • the contents are Cr: 0 to 1.00%, Mo: 0 to 1.00%, Cu: 0 to 1.00%, Ni: 0 to 1.00%, Co: 0 to 1.00%, W: 0 to 1.00%, Sn: 0 to 1.00%, Sb: 0 to 0.50%, Nb: 0 to 0.200%, Ti: 0 to 0.200%, V: 0 to 1.00%, and B: 0 to 0.0050%.
  • the elements may also be 0.001% or more, 0.005% or more, or 0.010% or more.
  • the B content may also be 0.0001% or more or 0.0002% or more.
  • the B content may also be 0.0030% or less, 0.0010% or less, less than 0.0005%, 0.0004% or less, or 0.0003% or less.
  • Ca (calcium), Mg (magnesium), Ce (cerium), Zr (zirconium), La (lanthanum), Hf (hafnium), and REM (rare earth metal) other than Ce and La are elements contributing to fine dispersion of steel inclusions.
  • Bi bismuth
  • Mn, Si, and other substitution type alloy elements in steel contribute to improvement of the workability of steel sheet, therefore one or more of these elements may be added according to need. However, excessive addition triggers deteriorate of the ductility. Therefore, the contents have 0.0150% or 0.0100% as upper limits. Further, the elements may be 0.0001% or more, 0.0005% or more, or 0.0010% or more.
  • the balance besides the above-mentioned elements is comprised of Fe and impurities.
  • Impurities are constituents, etc., entering due to various factors in the production process, first and foremost raw materials such as ore and scrap, when industrially producing the base steel sheet.
  • Ferrite is excellent in ductility, but is a soft structure and is preferably included in accordance with need.
  • the content in this case may be, by vol%, 1% or more, 5% or more, or 10% or more.
  • the content is, by vol%, 50% or less and may also be 45% or less, 40% or less, or 35% or less.
  • Tempered martensite is a high strength and tough structure and a metallographic structure essential in an embodiment of the present invention.
  • the tempered martensite content is, by vol%, 1% or more.
  • the tempered martensite content is preferably 5% or more and may be 10% or more or 20% or more.
  • the upper limit is not particularly prescribed, but for example the tempered martensite content may be, by vol%, 90% or less, 80% or less, 70% or less, or 50% or less.
  • Retained austenite improves the ductility of steel sheet by the TRIP effect of transformation to martensite by work induced transformation during deformation of the steel sheet. For this reason, the retained austenite content is, by vol%, 5% or more and may be 8% or more, 9% or more, 10% or more, or 11% or more. Retained austenite rises in elongation the greater the amount, therefore there is no need to prescribe an upper limit value. However, to obtain a large amount of retained austenite, a need arises to include a large amount of C or other alloy elements. In the present invention, an upper limit is set for the C content, therefore it is de facto difficult to obtain 30% or more of retained austenite. Therefore, the retained austenite content may be, by vol%, 30% or less, 25% or less, or 20% or less.
  • fresh martensite means martensite which is not tempered, i.e., martensite not containing carbides.
  • This fresh martensite is a brittle structure, therefore becomes starting points of fracture at the time of plastic deformation and causes deterioration of the local ductility of steel sheet. Therefore, the content is, by vol%, 0 to 15%.
  • the fresh martensite content is preferably, by vol%, 0 to 10% or 0 to 5%.
  • the fresh martensite content may also be, by vol%, 1% or more or 2% or more.
  • Pearlite contains hard and coarse cementite and becomes starting points of fracture at the time of plastic deformation, therefore causes deterioration of the local ductility of steel sheet. Therefore, the content, together with cementite, is, by vol%, 0 to 5% and may be 0 to 3% or 0 to 2%.
  • the balance of the metallographic structure of the base steel sheet according to an embodiment of the present invention is comprised of bainite.
  • the bainite of the remaining structure may be any of upper bainite having carbides between laths, lower bainite having carbides inside the laths, bainitic ferrite not having carbides, or granular bainite in which the lath boundaries of the bainite have recovered and become unclear or may be mixed structures of the same.
  • the bainite content of the balance may be 0%.
  • the bainite content of the balance may be, by vol%, 1% or more, 5% or more, or 10% or more.
  • the upper limit is not particularly prescribed, but for example the bainite content of the balance may be, by vol%, 70% or less, 60% or less, 57% or less, 55% or less, 50% or less, or 40% or less.
  • the percentages of the steel structures are evaluated by secondary electron images obtained using FE-SEM and the X-ray diffraction.
  • a sample is taken having a cross-section of thickness parallel to the rolling direction of the steel sheet and at the center position in the width direction as the examined surface.
  • the examined surface is machine polished to finish it to a mirror surface, then is etched using a Nital solution.
  • a secondary electron image is captured for a total area of 2.0 ⁇ 10 -9 m 2 or more.
  • the area ratios of the ferrite, retained austenite, bainite, tempered martensite, fresh martensite, and pearlite are respectively measured. These are deemed the volume percentages.
  • a region having lower structures inside the grains and precipitating with cementite having several variants is judged tempered martensite.
  • the region where cementite precipitates in a lamellar form is judged to be pearlite (or total of pearlite and cementite).
  • a region with a small luminance and no lower structures recognized are judged to be ferrite.
  • a region with a large luminance and with lower structures not appearing by etching are judged to be fresh martensite and retained austenite.
  • Regions not corresponding to any of the above region are judged to be bainite.
  • the volume ratios of these are calculated by the point counting method and deemed the volume ratios of the structures.
  • the volume ratio of fresh martensite can be found by subtracting the volume ratio of retained austenite found by the X-ray diffraction method.
  • the volume ratio of the retained austenite is measured by the X-ray diffraction method. That is, the material of the base steel sheet is removed by machine polishing and chemical polishing down to a depth 1/4 position from the sheet surface in the thickness direction. Further, the polished sample was analyzed using MoK ⁇ 1 rays as the characteristic X-rays. The structural percentage of retained austenite is calculated from the integrated intensity ratios of the diffraction peaks of the bcc phase (200) and (211) and fee phase (200), (220), and (311). These are made the volume ratios of the retained austenite.
  • the base steel sheet according to an embodiment of the present invention has a hot dip galvanized layer on at least one surface, preferably on both surfaces.
  • the plating layer may be a hot dip galvanized (GI) layer having any composition known to persons skilled in the art and may contain Al, Mg, Si, Fe, and other added elements besides the Zn.
  • GI hot dip galvanized
  • the amount of deposition of the plating layer is not particularly limited and may be a general amount of deposition.
  • the general amount of deposition in the case of use for automobile applications is for example 20 to 100 g/m 2 per surface.
  • the number density of recessed parts with depths of more than 2 ⁇ m at the interface of the base steel sheet and hot dip galvanized layer is 2.0/100 ⁇ m or less per interface length.
  • Recessed parts with depths of more than 2 ⁇ m easily accumulate Zn melted by the heat input at the time of spot welding and function as parts where stress concentrates, therefore become starting points of LME cracking. Therefore, if the number density of such recessed parts becomes higher, specifically if that number density becomes more than 2.0/100 ⁇ m, the LME cracking sensitivity remarkably deteriorates.
  • the number density of such recessed parts is more preferably 1.0/100 ⁇ m or less.
  • the lower limit of the number density is preferably 0.0/100 ⁇ m and may be 0.1/100 ⁇ m.
  • the number density of recessed parts is measured as follows.
  • a sample is taken having a cross-section of thickness parallel to the rolling direction of the hot dip galvanized steel sheet and at the center position in the width direction as the examined surface.
  • the examined surface is machine polished to finish it to a mirror surface, then a reflected electron image is taken of the plating/steel sheet interface by an imaging power of 500X using FE-SEM ( FIG. 1(a) ).
  • the obtained reflected electron image is digitalized to clarify the interface of the hot dip galvanized layer and the base steel sheet ( FIG. 1(b) ).
  • the converted digitalized image is converted to numerical data to obtain the height profile of the interface ( FIG. 1(c) ).
  • the center line is found by the least square method from the height profile and a region dissociated to the minus side with a surface height of more than 2 ⁇ m from the center line is deemed a "recessed part with a depth of more than 2 ⁇ m at the interface of the base steel sheet and hot dip galvanized layer".
  • Similar analysis is performed in a total measurement range in the X-direction (rolling) of more than 1 mm. For example if the size in the X-direction (rolling direction) in one field was 200 ⁇ m, the above analysis is performed at least five times while changing the field.
  • the numbers of "recessed parts with depths of more than 2 ⁇ m at the interface of the base steel sheet and hot dip galvanized layer" obtained at the fields are totaled up and converted to the number density per 100 ⁇ m interface length. This is determined as "the number density of recessed parts with depths of more than 2 ⁇ m at the interface of the base steel sheet and hot dip galvanized layer".
  • the "interface length” means the length along the height profile of the interface such as shown in FIG. 1(c) and can be measured using image analysis software.
  • the general practice is to use a contact type or laser type roughness meter, but if measuring the interface of plating and a base steel sheet (base iron) like in the present invention, first it is necessary to dissolve and peel off the plating by an acid.
  • a contact type or laser type roughness meter if measuring the interface of plating and a base steel sheet (base iron) like in the present invention, first it is necessary to dissolve and peel off the plating by an acid.
  • the hot dip galvanized steel sheet according to an embodiment of the present invention has an Al rich layer at the interface of the base steel sheet and hot dip galvanized layer.
  • the "Al rich layer” means a region with an Al concentration 10% or more higher than the Al concentration in the hot dip galvanized layer and 10% or more higher than the Al concentration in the base steel sheet.
  • the Al concentration in the hot dip galvanized layer means the Al concentration by a high frequency glow discharge optical emission spectrometer (GDS) at the 1/2 position of the thickness of the hot dip galvanized layer.
  • GDS glow discharge optical emission spectrometer
  • the 1/2 position of the thickness of the hot dip galvanized layer corresponds to an intermediate position between the interface of the base steel sheet and hot dip galvanized layer identified in measurement by GDS explained later and the surface of the hot dip galvanized steel sheet.
  • the Al concentration in the base steel sheet means the Al concentration corresponding to the average value of the Al emission intensity by GDS at 100 to 150 ⁇ m depth from the surface of the hot dip galvanized steel sheet. It is believed that by the presence of the Al rich layer at the interface of the base steel sheet and hot dip galvanized layer, it is possible to suppress the invasion of molten Zn in the base steel sheet. In relation to this, it becomes possible to improve the LME cracking sensitivity. From the viewpoint of reliable improvement of the LME cracking sensitivity, the maximum value of Al concentration of the Al rich layer is 2.0 mass% or more, preferably 2.5 mass% or more. The effect of improvement of the LME cracking sensitivity becomes greater the higher the Al concentration of the Al rich layer.
  • the upper limit is not particularly prescribed, but for example the maximum value of the Al concentration of the Al rich layer may be 8.0 mass% or less, 6.0 mass% or less, 5.0 mass% or less, 4.5 mass% or less, or 4.1 mass% or less.
  • the maximum value of the Al concentration of the Al rich layer is measured by a high frequency glow discharge optical emission spectrometer (GDS).
  • GDS glow discharge optical emission spectrometer
  • the method is used of rendering the surface of the hot dip galvanized steel sheet an Ar atmosphere, applying voltage to cause the generation of glow discharge, and in that state sputtering the steel sheet surface while analyzing it in the depth direction. Further, from the emission spectrum wavelengths unique to the elements generated by excitation of atoms in the glow plasma, the elements included in the material (hot dip galvanized steel sheet) are identified and the emission intensities of the identified elements are estimated. Data in the depth direction can also be estimated from the sputter time.
  • the sputter time can be converted to sputter depth. Therefore, the sputter depth converted from the sputter time can be defined as the depth from the surface of the material.
  • a commercial analysis apparatus In the present embodiment, a high frequency glow discharge optical emission spectrometer GD-Profiler2 made by Horiba Ltd. is used. The obtained emission intensity is converted to mass% by creating a calibration line in the following way. The average value of the emission intensity is calculated in a range of depth where the emission intensity is sufficiently stable.
  • the average value of the emission intensity at 100 to 150 ⁇ m depth from the surface of the hot dip galvanized steel sheet is the average value of the emission intensity at 100 to 150 ⁇ m depth from the surface of the hot dip galvanized steel sheet. This average value corresponds to the amount of Al [mass%] of the base steel sheet. Further, if the emission intensity is 0, the mass% is also 0. The calibration curve is created by these two points. The position of the interface of the base steel sheet and hot dip galvanized layer can be judged from the emission intensity of Zn.
  • FIG. 2 One example of the emission intensity of Zn in the case of measurement by GDS is shown in FIG. 2 .
  • the position where the emission intensity of Zn sharply falls corresponds to the interface of the base steel sheet and hot dip galvanized layer.
  • FIG. 3 one example of the Al concentration (emission intensity) in the case of measurement by GDS is shown in FIG. 3 .
  • the peak of Al concentration appears at the position where the emission intensity of Zn sharply falls in FIG. 2 .
  • the Al concentration calculated from the emission intensity of such a peak appearing at the point where the emission intensity of Zn sharply falls or its vicinity in the case of measurement by GDS (Almax in FIG. 3 ) is determined as "the maximum value of the Al concentration of the Al rich layer present at the interface of the base steel sheet and hot dip galvanized layer.”
  • the hot dip galvanized steel sheet according to an embodiment of the present invention has a poor region of Si in the base steel sheet right under the interface of the base steel sheet and hot dip galvanized layer.
  • "right under the interface” means the region up to 10 ⁇ m from the interface of the base steel sheet and hot dip galvanized layer in the depth direction. More specifically, it means the region up to 10 ⁇ m from the interface of the base steel sheet and hot dip galvanized layer identified by measurement by GDS in the depth direction.
  • Si is an element causing deterioration of the LME cracking sensitivity, therefore by the presence of such an Si poor region in the base steel sheet right under the plating interface contacting the molten Zn, it becomes possible to improve the LME cracking sensitivity.
  • Si s /Si b (where, Si s is the local minimum value of Si emission intensity at base steel sheet right under interface of base steel sheet and hot dip galvanized layer and Si b is the average value of Si emission intensity at the base steel sheet) is 0.90 or less, preferably 0.85 or less.
  • the effect of improvement of the LME cracking sensitivity becomes larger the lower the Si s /Si b .
  • the lower limit is not particularly prescribed, but, for example, Si s /Si b may be 0.10 or more, 0.30 or more, 0.50 or more, 0.60 or more, or 0.65 or more.
  • Si s and Si b are measured by a high frequency glow discharge optical emission spectrometer (GDS) in the same way as the case of the maximum value of Al concentration of the Al rich layer. Details of the measurement condition are as described in relation to the maximum value of Al concentration of the Al rich layer.
  • the average value need only be calculated in a range of depth where the Si b emission intensity is sufficiently stable. For example, may be the average value of the emission intensity at a range of 100 to 150 ⁇ m depth from the surface of the hot dip galvanized steel sheet.
  • FIG. 4 shows an example of measurement. Referring to FIG. 4 , it will be understood that the local minimum value of Si (Si s ) in the base steel sheet right under the interface of the base steel sheet and hot dip galvanized layer appears.
  • the hot dip galvanized steel sheet according to an embodiment of the present invention excellent mechanical properties, for example, high strength, specifically a 980 MPa or more tensile strength (TS), can be achieved.
  • the tensile strength is preferably 1080 MPa or more, more preferably 1180 MPa or more.
  • the upper limit is not particularly prescribed, but for example the tensile strength may be 2000 MPa or less, 1800 MPa or less, 1600 MPa or less, or 1500 MPa or less.
  • a high ductility can be achieved. More specifically an 8.0% or more, preferably 10.0% or more, more preferably 12.0% or more or 15.0% or more total elongation (El) can be achieved.
  • the upper limit is not particularly prescribed, but for example the total elongation may be 40.0% or less or 35.0% or less.
  • the tensile strength and total elongation are measured by taking a JIS No. 5 tensile test piece from a direction perpendicular to the rolling direction of the steel sheet and conducting a tensile test based on JIS Z2241: 2011. Further, according to the hot dip galvanized steel sheet according to an embodiment of the present invention, a high hole expandability can be achieved. More specifically a 18% or more, preferably 20% or more, more preferably 25% or more hole expansion ratio ( ⁇ ) can be achieved.
  • the upper limit is not particularly prescribed, but for example the hole expansion ratio may be 80% or less or 70% or less.
  • the hole expansion ratio is measured by conducting a test by the "JFS T 1001 Hole Expansion Test Method" of the Japan Iron and Steel Federation standard.
  • the balance of the tensile strength (TS), total elongation (El), and hole expansion ratio ( ⁇ ) can be improved at a high level, therefore it is possible to achieve a press-formability preferable for use as a member for automotive use.
  • the hot dip galvanized steel sheet according to an embodiment of the present invention has a thickness of, for example, 0.6 to 4.0 mm. While not particularly limited, the sheet thickness may be 0.8 mm or more, 1.0 mm or more, or 1.2 mm or more. Similarly, the sheet thickness may be 3.0 mm or less, 2.5 mm or less, or 2.0 mm or less.
  • a slab having the same chemical composition as the chemical composition explained relating to the base steel sheet is heated before hot rolling, then is subjected to rough rolling and finish rolling.
  • the heating temperature of the slab is not particularly limited, but generally preferably is 1150°C or more so as to sufficiently dissolve borides, carbides, etc.
  • the steel slab used is preferably cast by the continuous casting method from the viewpoint of manufacturability, but may also be produced by the ingot casting method or thin slab casting method.
  • the heated slab may also be rough rolled before finish rolling.
  • the rough rolling conditions are not particularly limited, but the rough rolling is preferably performed so that the end temperature becomes 1050°C or more and the total rolling reduction becomes 60% or more. If the total rolling reduction is less than 60%, the recrystallization during hot rolling becomes insufficient, therefore this sometimes leads to uneven quality of the hot rolled steel sheet structure.
  • the total rolling reduction for example, may be 90% or less.
  • the steel sheet is finish rolled.
  • the conditions are not particularly limited, but the step is preferably performed in a range satisfying the conditions of a finish rolling entry side temperature of 950 to 1 100°C, a finish rolling exit side temperature of 850 to 1000°C, and a total rolling reduction of 80 to 95%. If the finish rolling entry side temperature falls below 950°C, the finish rolling exit side temperature falls below 850°C, or the total rolling reduction rises above 95%, the hot rolled steel sheet is forms texture, therefore sometimes the anisotropy at the final product sheet becomes remarkable.
  • finish rolling entry side temperature rises above 1 100°C
  • finish rolling exit side temperature rises above 1000°C
  • total rolling reduction falls below 80%
  • the hot rolled steel sheet after finish rolling is, for example, cooled to 700°C or less, then taken up in a coil.
  • the coiling temperature is preferably 450 to 680°C. If the coiling temperature falls below 450°C, sometimes the strength of the hot rolled sheet becomes excessive and the cold rollability is impaired. On the other hand, if the coiling temperature rises above 680°C, Mn and other alloy elements concentrate at the cementite, therefore in the final annealing step, sometimes cementite is slow to dissolve and a drop in strength is triggered.
  • the coiling temperature may be 500°C or more and/or may be 650°C or less or 600°C or less.
  • the hot rolled coil after coiling (hot rolled steel sheet) is cooled so as to satisfy the following formula (1).
  • [Mathematical 5] 0.05 ⁇ 2 ⁇ ⁇ t 0 tf Do ⁇ No N x ⁇ ⁇ t ⁇ 1.50
  • [Mathematical 6] D o 2.9 ⁇ 10 ⁇ 7 ⁇ exp ⁇ 90,000 8.314 ⁇ T t
  • N o 0.381 ⁇ exp ⁇ 104,000 8.314 ⁇ T t
  • Formula (1) shows that the greater the ⁇ value, the more an internal oxidation reaction proceeds at the steel sheet surface.
  • the ⁇ in formula (1) is calculated by quadrature by parts.
  • ⁇ t is a finite value and corresponds to the measurement pitch of temperature T(t). For example, it is 100 seconds.
  • Do is the diffusion coefficient of oxygen atoms at the temperature T(t)
  • No is amount of oxygen atoms dissolved in the steel at the temperature T(t)
  • Nx is the total amount of the main elements to be internally oxidized in the steel.
  • Nx can be calculated by converting the mass percentages of the elements (Si, Mn, Al) to atomic percentages and adding them up. If converting this to a formula, the result becomes the formula (5).
  • N x Si M Si + Mn M Mn + Al M Al Fe M Fe + C M C + Si M Si + Mn M Mn + P M Al + S M Al + Al M Al + N M N ...
  • [X] is the mass percentage of the element X
  • Mx is the atomic percentage of the element X.
  • the denominator of the formula (5) is the total of all elements added to the steel in question.
  • formula (1) means that the greater the diffusion coefficient of oxygen atoms or the greater the amount of dissolved oxygen, the easier it is for the internal oxidation reaction to proceed and the greater the amount of elements to be internally oxidized, the harder it is for it to proceed.
  • the Si dissolved in the steel is consumed by the formation of internal oxides, therefore an Si poor layer is formed right under the internal oxidation layer.
  • Si in particular the Si dissolved in the steel, is an element causing the deterioration of the LME cracking sensitivity.
  • this Si poor layer can be made to remain in up to the final product by limiting the pickling conditions as explained later.
  • the value of formula (1) is limited to more than 0.05 to less than 1.50. Preferably, it is 0.10 to 1.00, more preferably 0.20 to 0.70.
  • the hot rolled steel sheet obtained in the hot rolling step is pickled by running it through a temperature 70 to 90°C aqueous solution containing 1.0 to 5.0 mol/L of HCl, less than 3.0 mol/L of Fe 2 + , and less than 0.10 mol/L of Fe 3 + by an average speed of 10 m/min or more for 30 seconds or more.
  • the hot rolled steel sheet before pickling is deformed by bending and unbending at least once by a tension leveler, etc.
  • the pickling does not sufficiently proceed and the internal oxidation layer is unevenly removed.
  • the number density of recessed parts with depths of more than 2 ⁇ m at the steel sheet/plating interface of the final product increases.
  • the hot rolled steel sheet after pickling is then cold rolled.
  • the rolling reduction of the cold rolling is 30% or more so as to promote recrystallization and/or flatten relief shapes of steel sheet after pickling. If the rolling reduction is less than 30%, the relief shapes at the steel sheet surface cannot be sufficiently flattened and the number density of recessed parts with depths of more than 2 ⁇ m at the steel sheet/plating interface of the final product increases.
  • the rolling reduction may also be 40% or more.
  • excessive rolling reduction causes excessive rolling load and invites an increase in load of the cold rolling mill, therefore the upper limit is 75% or 70%.
  • the obtained cold rolled steel sheet is subjected to predetermined heat treatment and plating at the heat treatment and plating step. Specifically, first, the cold rolled steel sheet is heated so that the average heating speed from 600°C to an Ac1+30°C to 950°C maximum heating temperature becomes 0.2 to 20°C/s and an atmosphere around the cold rolled steel sheet satisfies the following formula (4): [Mathematical 9] ⁇ 1.0 ⁇ log pH 2 O pH 2 ⁇ ⁇ 0.1
  • the more preferable range is -0.9 to -0.2, more preferably -0.8 to -0.3.
  • the maximum heating temperature from 600°C to the Ac1+30°C to 950°C is limited to 0.2 to 20°C/s. If more than 20°C/s, the internal oxidation reaction does not sufficiently proceed. On the other hand, if less than 0.2°C/s, coarsening of the structure and the decarburization reaction excessively proceed and thereby the strength falls.
  • the preferable average heating speed is 0.5 to 10°C/s, more preferably 1 to 7°C/s.
  • the cold rolled steel sheet is heated to at least the Ac1+30°C or more and soaking is performed at that temperature (maximum heating temperature). If austenite is not sufficiently formed, sometimes ferrite is formed in a large amount at the final structure. However, if excessively raising the heating temperature, not only is deterioration of the toughness due to coarsening of the austenite grain size, but also damage to the annealing facilities is caused. For this reason, the upper limit is 950°C, preferably 900°C. If the soaking time is short, the formation of austenite does not sufficiently proceed, therefore it is at least 1 second or more.
  • the soaking time is preferably 30 seconds or more or 60 seconds or more.
  • the upper limit is 1000 seconds, preferably 600 seconds.
  • the cold rolled steel sheet does not necessarily have to be held at a constant temperature and may fluctuate within a range satisfying the above conditions.
  • the cold rolled steel sheet after the heating and holding is cooled and dipped in a hot dip galvanization bath.
  • the steel sheet is preferably cooled so that the average cooling speed in the 550 to 700°C temperature range becomes 10 to 100°C/s.
  • the steel sheet temperature at the time of dipping in the hot dip galvanization bath if the difference between the steel sheet temperature and the plating bath temperature is too great, sometimes the plating bath temperature changes and the operation is obstructed. For this reason, the steel sheet temperature is preferably the plating bath temperature-20°C to the plating bath temperature+20°C.
  • the hot dip galvanization may be performed in accordance with the usual method.
  • the plating bath temperature may be 440 to 480°C, and the dipping time may be 5 seconds or less.
  • the plating bath preferably contains Al in 0.1 to 0.5 mass%.
  • impurities Fe, Si, Mg, Mn, Cr, Ti, Pb, etc.
  • the basis weight of the plating is controlled by the gas wiping. The basis weight may be suitably changed in accordance with the corrosion resistance demanded, but, or example, 20 to 100 g/m 2 per surface is preferable.
  • the time until gas wiping after dipping in the plating bath is limited to 0.1 to 5 seconds.
  • the upper limit is not particularly prescribed, but, for example, the steel sheet temperature after gas wiping may be 300°C or more.
  • the lower limit of the time until gas wiping is determined by the hardware configuration, but on a usual hot dip galvanization line, making it lower than 0.1 second is difficult.
  • the steel sheet is cooled to the martensite transformation start temperature (Ms) to Ms-200°C in range.
  • Ms martensite transformation start temperature
  • the martensite formed here is tempered by later reheating and holding treatment and becomes tempered martensite. If the cooling step temperature rises above Ms, the tempered martensite is not formed, therefore the desired metallographic structure is not obtained. On the other hand, if the cooling stop temperature falls below Ms-200°C, the nontransformed austenite is excessively decreased, therefore the desired retained austenite content is not obtained.
  • the preferable range of the cooling stop temperature is Ms-20 to Ms-150°C, more preferably Ms-40 to Ms-100°C.
  • Martensite transformation occurs after ferrite transformation and/or bainite transformation. Along with the above transformation, C is distributed in the austenite. For this reason, this does not match with the Ms when heating to the austenite single phase and rapidly cooling.
  • the Ms in an embodiment of the present invention is found by measuring the thermal expansion temperature.
  • Ms can be found by using a Formaster tester or other apparatus able to measure the amount of thermal expansion during continuous heat treatment to reproduce the heat cycle from the start of heat treatment (corresponding to room temperature) to cooling to the Ms or less and measure the amount of thermal expansion during that time.
  • the steel sheet thermally contracts linearly during cooling, but deviates from a linear relationship at a certain temperature.
  • the temperature at this time is Ms in an embodiment of the present invention.
  • the steel sheet After cooling to Ms to Ms-200°C in range, the steel sheet is reheated and held at 300°C to 420°C in range. In this treatment, to obtain the desired retained austenite content, carbon is made to concentrate in the austenite and the austenite is made to stabilize (austempering). At the same time, the martensite formed by the cooling is tempered. If the reheating temperature is less than 300°C or the holding time is less than 100 seconds, the carbon is insufficiently concentrated at the austenite. In the process of cooling to room temperature after that, the ratio of the austenite remaining in the nontransformed austenite until room temperature and becoming retained austenite is decreased and the ratio of formation of fresh martensite increases.
  • the content of the retained austenite falls below, by vol%, the lower limit of 5% and/or the content of the fresh martensite rises above, by vol%, 15%.
  • the reheating temperature rises above 420°C or the holding time rises above 600 seconds, the austenite breaks down into cementite, therefore the desired retained austenite content is not obtained.
  • the order of (D3) and (D4) is not an issue. For example, after dipping in the plating bath, the steel sheet may be cooled to Ms to Ms-200°C in range and dipped in the plating bath after finishing the step of (D4).
  • the conditions of the examples are illustrations of the conditions employed for confirming the workability and effect of the present invention.
  • the present invention is not limited to these illustrations of conditions.
  • the present invention can employ various conditions so long as not deviating from the gist of the present invention and achieving the object of the present invention.
  • JIS No. 5 tensile test pieces were taken from a direction perpendicular to the rolling direction of the hot dip galvanized steel sheets obtained in the above way and tensile tests based on JIS Z2241: 2011 to measure the tensile strength (TS) and total elongation (El). Further, the "JFS T 1001 Hole Expansion Test Method" of the Japan Iron and Steel Federation standard was used to measure the hole expansion ratio ( ⁇ ). Samples with a TS of 980 MPa or more and a TS ⁇ El ⁇ 0.5 /1000 of 90 or more were excellent in mechanical properties and judged to have press-formability preferable for use as members for automotive use.
  • liquid metal embrittlement (LME) fracturing ability of the spot welds 150 mm width ⁇ 50 mm length test pieces were obtained and pairs were subjected to spot welding tests.
  • the sheets were made pairs of the same steel sheets shown in Table 3 which were welded in the state with weld angles of 3°.
  • a servo motor-driven type stationary spot welding test apparatus was used for the test apparatus.
  • the power source was made a single-phase AC 50Hz, weld pressure 400 kgf, weld time 20 cycles, and hold time 5 cycles.
  • the values of the weld currents were made values of currents giving diameters of the molten nuggets of 4.0 times, 5.0 times, and 5.5 times of ⁇ t (t: sheet thickness/mm).
  • Electrodes made of chrome copper with tip diameters of ⁇ 6 mm and tip bending radii R of 40 mm were used.
  • the welded samples were examined at cross-sections of the nugget parts. Samples with 0.2 mm or more cracks observed at any of the current values were judged as "P” (poor), samples with 0.1 mm or more and less than 0.2 mm cracks observed at any of the current values were judged as "G” (good), and samples with less than 0.1 mm cracks observed at any of the current values were evaluated as "VG” (very good).
  • P probability density
  • Comparative Example 17 the time until gas wiping after dipping in the plating bath was long, therefore it is believed fracture of the Al rich layer present at the interface of the base steel sheet and hot dip galvanized layer ended up starting and as a result the maximum value of the Al concentration of the Al rich layer fell and cracking occurred in the spot welds.
  • Comparative Example 18 the temperature of the steel sheet after gas wiping was high, therefore similarly it is believed that the Al rich layer ended up starting to fracture and as a result the maximum value of the Al concentration of the Al rich layer fell and cracking occurred in the spot welds.
  • Comparative Example 19 the value of formula (4) was low and therefore internal oxidation did not sufficiently proceed, therefore it is believed that the Si poor layer could not be sufficiently formed. As a result, the value of Si s /Si b became higher and cracking occurred in the spot welds.
  • Comparative Example 20 the reheating temperature at the heat treatment and/or plating step was low, therefore the desired retained austenite content could not be obtained and the press-formability was inferior.
  • the cooling temperature at the heat treatment and/or plating step was high, therefore tempered martensite was not formed and the press-formability was inferior.
  • the holding time at the reheating temperature in the heat treatment and/or plating step was short, therefore the fresh martensite content became high and the press-formability was inferior.
  • Comparative Example 33 the reheating temperature at the heat treatment and/or plating step was high, therefore the desired retained austenite content could not be obtained and the press-formability was inferior.
  • Comparative Example 34 the holding time at the reheating temperature at the heat treatment and/or plating step was long, therefore similarly the desired retained austenite content could not be obtained and the press-formability was inferior.
  • Comparative Example 35 the cooling temperature at the heat treatment and/or plating step was low, therefore nontransformed austenite was excessively decreased and similarly the desired retained austenite content could not be obtained and the press-formability was inferior.
  • Comparative Example 36 the rolling reduction of the cold rolling was low, therefore the steel sheet surface could not be sufficiently flattened and at the finally obtained hot dip galvanized steel sheet, the number density of recessed parts with depths of more than 2 ⁇ m at the interface of the base steel sheet and hot dip galvanized layer increased and as a result cracking occurred in the spot welds.
  • Comparative Example 37 the value of formula (4) became high and therefore not only did Si, etc., become internally oxidized, but Fe also became oxidized and nonplating ended up occurring. For this reason, Comparative Example 37 was excluded from coverage of evaluation as hot dip galvanized steel sheet.
  • Comparative Examples 46 to 48 and 50 to 52 the chemical composition was not controlled to within a predetermined range, therefore the press-formability was inferior.
  • Comparative Example 49 the Si content was high, therefore cracking occurred in the spot welds.
  • Comparative Examples 53 and 54 the pickling time was short, therefore it is believed the pickling did not sufficiently proceed and the internal oxidation layer was unevenly removed. As a result, the number density of the recessed parts with depths of more than 2 ⁇ m at the interface of the base steel sheet and hot dip galvanized layer increased and cracking occurred in the spot welds.
  • the TS was 980 MPa or more and TS ⁇ El ⁇ 0.5 /1000 was 90 or more and, furthermore, the test results of the LME cracking resistance of the spot welds were excellent, therefore it was learned that the press-formability and LME cracking resistance of the spot welds are excellent.

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)
  • Coating With Molten Metal (AREA)
EP22920482.1A 2022-01-13 2022-11-29 Tôle en acier galvanisée par immersion à chaud, et procédé de fabrication de celle-ci Pending EP4464802A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2022003757 2022-01-13
PCT/JP2022/043968 WO2023135962A1 (fr) 2022-01-13 2022-11-29 Tôle en acier galvanisée par immersion à chaud, et procédé de fabrication de celle-ci

Publications (1)

Publication Number Publication Date
EP4464802A1 true EP4464802A1 (fr) 2024-11-20

Family

ID=87278932

Family Applications (1)

Application Number Title Priority Date Filing Date
EP22920482.1A Pending EP4464802A1 (fr) 2022-01-13 2022-11-29 Tôle en acier galvanisée par immersion à chaud, et procédé de fabrication de celle-ci

Country Status (7)

Country Link
US (1) US20240327962A1 (fr)
EP (1) EP4464802A1 (fr)
JP (1) JPWO2023135962A1 (fr)
KR (1) KR20240121797A (fr)
CN (1) CN118525107A (fr)
MX (1) MX2024007820A (fr)
WO (1) WO2023135962A1 (fr)

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4445365B2 (ja) 2004-10-06 2010-04-07 新日本製鐵株式会社 伸びと穴拡げ性に優れた高強度薄鋼板の製造方法
JP5332981B2 (ja) 2009-07-08 2013-11-06 新日鐵住金株式会社 延性及び耐食性に優れた合金化溶融亜鉛めっき鋼板及びその製造方法
JP5333298B2 (ja) 2010-03-09 2013-11-06 Ｊｆｅスチール株式会社 高強度鋼板の製造方法
CN103703157B (zh) 2011-07-29 2015-12-02 新日铁住金株式会社 形状保持性优异的高强度钢板、高强度镀锌钢板及它们的制造方法
CN103857821B (zh) * 2011-09-30 2016-01-27 新日铁住金株式会社 高强度热浸镀锌钢板
JP5454745B2 (ja) 2011-10-04 2014-03-26 Ｊｆｅスチール株式会社 高強度鋼板およびその製造方法
US10202664B2 (en) 2012-03-30 2019-02-12 Voestalpine Stahl Gmbh High strength cold rolled steel sheet
WO2016111272A1 (fr) * 2015-01-09 2016-07-14 株式会社神戸製鋼所 Tôle d'acier plaquée hautement résistante, et procédé de fabrication de celle-ci
JP6252713B1 (ja) 2016-04-14 2017-12-27 Ｊｆｅスチール株式会社 高強度鋼板およびその製造方法
WO2018189950A1 (fr) 2017-04-14 2018-10-18 Ｊｆｅスチール株式会社 Plaque d'acier et son procédé de production
WO2018203111A1 (fr) 2017-05-05 2018-11-08 Arcelormittal Procédé de production d'une tôle d'acier à haute résistance ayant une ductilité, une formabilité et une soudabilité élevées et tôle d'acier obtenue ainsi
WO2018234839A1 (fr) 2017-06-20 2018-12-27 Arcelormittal Tôle d'acier revêtue de zinc présentant une soudabilité par points de haute résistance
KR102599376B1 (ko) * 2019-02-06 2023-11-09 닛폰세이테츠 가부시키가이샤 용융 아연 도금 강판 및 그 제조 방법
EP3950994B1 (fr) * 2019-03-28 2024-01-24 Nippon Steel Corporation Tôle d'acier à haute résistance
MX2022011603A (es) * 2020-03-27 2022-10-18 Nippon Steel Corp Lamina de acero enchapada con zinc por inmersion en caliente.
KR20230084534A (ko) * 2020-11-11 2023-06-13 닛폰세이테츠 가부시키가이샤 강판 및 그 제조 방법

Also Published As

Publication number Publication date
CN118525107A (zh) 2024-08-20
MX2024007820A (es) 2024-07-04
KR20240121797A (ko) 2024-08-09
JPWO2023135962A1 (fr) 2023-07-20
US20240327962A1 (en) 2024-10-03
WO2023135962A1 (fr) 2023-07-20

Similar Documents

Publication Publication Date Title
EP3719157B1 (fr) Tôle d'acier galvanisée à résistance élevée et son procédé de fabrication
EP3309273B1 (fr) Tôle d'acier galvanisée et procédé pour sa fabrication
EP3719156B1 (fr) Tôle d'acier galvanisée à résistance élevée et son procédé de fabrication
EP2243852B1 (fr) Tôle d'acier galvanisée par immersion à chaud à haute résistance présentant une excellente aptitude au façonnage et son procédé de fabrication
US6410163B1 (en) High strength thin steel sheet, high strength alloyed hot-dip zinc-coated steel sheet, and method for producing them
EP3922745A1 (fr) Tôle d'acier galvanisée par immersion à chaud et son procédé de fabrication
EP3971308B1 (fr) Élément à haute résistance, procédé de fabrication d'élément à haute résistance et procédé de fabrication de tôle d'acier pour élément à haute résistance
WO2020136988A1 (fr) Tôle en acier galvanisé à chaud hautement résistante, et procédé de fabrication de celle-ci
JP7606111B2 (ja) 鋼板及びその製造方法
EP3575425A1 (fr) Plaque d'acier
KR102544887B1 (ko) 고강도 용융 아연 도금 강판 및 그의 제조 방법
JP7276618B2 (ja) 高強度冷延鋼板およびその製造方法
WO2024053663A1 (fr) Tôle d'acier plaquée
CN117062928A (zh) 镀锌钢板、部件以及它们的制造方法
JP7311808B2 (ja) 鋼板及びその製造方法
JP7136335B2 (ja) 高強度鋼板及びその製造方法
US12098440B2 (en) Steel sheet and method for producing same
WO2024053736A1 (fr) Tôle d'acier et son procédé de fabrication
EP4464802A1 (fr) Tôle en acier galvanisée par immersion à chaud, et procédé de fabrication de celle-ci
EP4043593B1 (fr) Tôle en acier hautement résistante ainsi que procédé de fabrication de celle-ci, et élément d'absorption de chocs
EP4043594B1 (fr) Tôle en acier hautement résistante ainsi que procédé de fabrication de celle-ci, et élément d'absorption de chocs
CN117716059A (zh) 镀锌钢板和部件以及它们的制造方法
EP4417726A1 (fr) Tôle d'acier laminée à froid, procédé de fabrication correspondant et joint soudé
WO2024176527A1 (fr) Feuille d'acier et son procédé de production
EP4467671A1 (fr) Tôle d'acier

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20240621

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC ME MK MT NL NO PL PT RO RS SE SI SK SM TR