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
• • 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
  • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
  • C21D1/76—Adjusting the composition of the atmosphere
• • 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
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
  • C21D8/0447—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment
  • C21D8/0473—Final recrystallisation annealing
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • 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
  • C21D8/0478—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing involving a particular 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
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
  • C21D9/48—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals deep-drawing sheets
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/002—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
  • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
• • 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
  • C23C2/02—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
  • C23C2/0222—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating in a reactive atmosphere, e.g. oxidising or reducing atmosphere
• • 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
  • C23C2/26—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
  • C23C2/261—After-treatment in a gas atmosphere, e.g. inert or reducing atmosphere
• • 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
  • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
  • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
  • C23C8/20—Carburising
  • C23C8/22—Carburising of ferrous surfaces
• • 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
  • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C8/80—After-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
  • C21D2211/00—Microstructure comprising significant phases
  • C21D2211/005—Ferrite

Definitions

• the present invention relates to an alloyed hot-dip galvanized steel sheet suitable as an automotive rust-proof surface-treated steel sheet and a method for producing the same.
• hot rolled steel sheets of TS440 MPa class or lower have been used for members such as automobile and truck frames and undercarriages.
• high strength and thinning of steel sheets for automobiles has been promoted, and high strength hot rolled steel sheets of TS590MPa class, TS780MPa class, and more than TS980MPa class. The use of is beginning to be considered.
• Automobile members often have complicated shapes obtained by press molding, and materials that are high in strength but excellent in workability are required.
• the surface treated steel sheet provided with rust resistance to the material steel sheet, especially alloyed molten zinc that is excellent in corrosion resistance and weldability after painting and can be manufactured at low cost. There is a need for plated steel sheets.
• Patent Document 1 in mass%, C: 0.02 to 0.06%, Si ⁇ 0.3%, Mn: 0.5 to 2.0%, P ⁇ 0.06%, S ⁇ 0 0.005%, Al ⁇ 0.06%, N ⁇ 0.006%, Mo: 0.05 to 0.5%, Ti: 0.03 to 0.14%, the balance being substantially made of Fe By melting steel and performing hot rolling under conditions of finish rolling finish temperature of 880 ° C. or higher and coiling temperature of 570 ° C.
• Ti and Mo having substantially a ferrite single phase structure and an average particle size of less than 10 nm are obtained.
• a high-strength steel sheet excellent in workability having a tensile strength of 590 MPa or more and a method for producing the same, characterized in that a carbide containing is dispersed and precipitated.
• Patent Document 2 by mass, C: 0.01 to 0.1%, Si ⁇ 0.3%, Mn: 0.2 to 2.0%, P ⁇ 0.04%, S ⁇ 0 0.02%, Al ⁇ 0.1%, N ⁇ 0.006%, Ti: 0.03 to 0.2%, and one or more of Mo ⁇ 0.5% and W ⁇ 1.0% Steel, the balance being Fe and inevitable impurities are melted, hot-rolled in the austenite single-phase region, wound at 550 ° C. or more, and after producing a single-phase ferrite hot-rolled steel sheet, the scale is further removed.
• the hot dip galvanizing As it is, it is 4.8C + 4.2Si + 0.4Mn + 2Ti ⁇ 2.5 by mass%, the structure is ferrite with an area ratio of 98% or more, and the atomic ratio is (Mo + W) / In the range satisfying (Ti + Mo + W) ⁇ 0.2, at least one of Ti, Mo and W Precipitates of less than 10nm, including a is characterized by the presence in the dispersion method of producing a hot-dip galvanized high-strength hot-rolled steel sheet is disclosed.
• the present invention has been made in view of such circumstances, and while ensuring good workability, the plating adhesion of the bent portion and the corrosion resistance after painting of the stretch flange portion are excellent, and further, the hydrogen embrittlement resistance is excellent.
• An object is to provide a high-strength hot-dip galvanized steel sheet.
• the present inventors obtained the following knowledge as a result of intensive studies on the plating treatment of high-strength steel sheets.
• the present inventors have found that in order to obtain a plated steel sheet having excellent hydrogen embrittlement resistance, the average particle size of the components in the plating layer, particularly oxides and carbides, is extremely important.
• the reason for this is that when a carbide having an average particle diameter of 10 nm or less and an oxide having an average particle diameter of 50 nm or more exist in the surface layer portion of the steel sheet, it acts as a hydrogen intrusion trap site and suppresses the concentration of diffusible hydrogen into the steel sheet. It is thought that the sensitivity of delayed fracture is suppressed. Furthermore, cracks are generated and propagated in the plating layer when subjected to compressive strain during press molding.
• the presence of fine carbides and oxides allows the fine carbides and oxides to have a pinning effect at the crack generation portion. It is presumed that this pinning effect stops the propagation of cracks and does not lead to large peeling, but improves the plating adhesion during bending. As a result, the corrosion resistance after painting is improved.
• the solid solution Ti present in the steel sheet surface layer portion is defined by prescribing the heating temperature when annealing the steel sheet thereafter.
• the present inventors have found that it is important to precipitate as carbide.
• the oxide layer obtained by oxidizing the steel sheet surface layer in the heating zone is used as a source of oxygen that internally oxidizes Ti during reductive annealing in the soaking zone. The inventors have found that this is essential.
• the present invention is based on the above findings, and the features thereof are as follows.
• C 0.02% to 0.30%
• Si 0.01% to 2.5%
• Mn 0.1% to 3.0%
• P 0.00. 00% or more and 0.08% or less
• S 0.01% or less
• Al 0.001% or more and 0.20% or less
• Ti 0.03% or more and 0.40% or less
• a steel plate surface having a component composition consisting of inevitable impurities has a galvanized layer with a coating amount of 20 to 120 g / m 2 on one side, and carbide with an average particle size of 10 nm or less per section 5.
• An alloyed hot-dip galvanized steel sheet characterized in that 5 or more and 50 or less oxides having an average particle diameter of 50 nm or more are present in a ratio of 5 or more and 50 or less per section.
• the one section is the plating layer thickness (t 1 ⁇ m) and the area (t 1 ⁇ 1 ( ⁇ m 2 )) obtained by dividing the plating layer cross section at intervals of 1 ⁇ m in the direction orthogonal to the thickness direction. It is.
• the carbide includes Ti
• the oxide includes one or more oxides selected from TiO 2 , MnO, MnO 2 , SiO 2 , Al 2 O 3 , Mn 2 SiO 4 , and MnSiO 3.
• the high-strength hot-dip galvanized steel sheet according to [1]. [3] The steel sheet further has a component composition of mass%, Nb: 0.001% to 0.2%, V: 0.001% to 0.5%, Mo: 0.01% or more.
• the high-strength hot-dip galvanized steel sheet as described.
• the steel having the component composition according to any one of [1], [3], and [4] is hot-rolled, and after finishing rolling, cooling and winding are performed, and then continuous annealing and A method for producing a high-strength hot-dip galvanized steel sheet, characterized in that when performing hot-dip galvanizing treatment, the finish rolling finish temperature is 850 ° C. or higher, the coiling temperature is 540 ° C. or lower, and continuous annealing is performed under the following conditions.
• the composition of the combustion gas in the heating zone of the annealing furnace is H 2 ⁇ 40 vol% or more, CH 4 ⁇ 20 vol%, CO 2 ⁇ 1 vol%, the balance CO, N 2 , C x H y (x ⁇ 2, y ⁇ 4), the steel plate is heated to 520 ° C. or higher and 650 ° C. or lower at a furnace temperature of 500 ° C. or higher and 1000 ° C. or lower, and an oxidation treatment is performed to form an oxide layer having a thickness of 6 to 60 nm on the steel plate surface layer.
• soaking zone atmosphere is balance N 2 include: hydrogen 5 vol% or more 50 vol%, and water vapor partial pressure (P H2 O) and hydrogen partial pressure (P H2) satisfies the equation (1) below Then, reduction annealing is performed at a temperature reached from 630 ° C. to 780 ° C. in the soaking zone. 10 ⁇ 3 ⁇ P H2O / P H2 ⁇ 10 ⁇ 1 (1) However, PH2O shows water vapor partial pressure (Pa), and PH2 shows hydrogen partial pressure (Pa). [7] After the hot dipping treatment, the steel plate is further heated to a temperature of 450 ° C. or higher and 510 ° C.
• the high strength means that the tensile strength TS is 590 MPa or more.
• the alloyed hot-dip galvanized steel sheet of the present invention includes both cold-rolled steel sheets and hot-rolled steel sheets, and hot-rolled steel sheets are particularly preferable from the viewpoints of stretch flangeability and hole-expandability.
• the present invention it is possible to obtain a high-strength hot-dip galvanized steel sheet that is excellent in plating adhesion at the bent portion and corrosion resistance after coating at the stretch flanged portion, and further excellent in hydrogen embrittlement resistance while ensuring good workability.
• Component composition C of steel sheet 0.02% or more and 0.30% or less C is an element necessary for precipitating carbide in the steel sheet, and for that purpose, 0.02% or more is necessary. On the other hand, if it exceeds 0.30%, the weldability deteriorates, so the upper limit is made 0.30%.
• Si 0.01% or more and 2.5% or less Si is effective as a solid solution strengthening element.
• it is necessary to contain 0.01% or more.
• Si oxide concentrates on the surface of the steel sheet during the annealing process, causing non-plating defects and plating adhesion deterioration, so the upper limit is 2.5%. To do.
• Mn 0.1% or more and 3.0% or less Mn is added for increasing the strength, and it is necessary to contain 0.1% or more for the strengthening effect to appear. On the other hand, if the content exceeds 3.0%, the Mn oxide is concentrated on the surface of the steel sheet during the annealing process, causing non-plating defects and plating adhesion deterioration, so the upper limit is made 3.0%.
• P 0.003% or more and 0.08% or less P is one of the elements inevitably contained, and in order to make it less than 0.003%, there is a concern about an increase in cost, so 0.003% That's it.
• P exceeds 0.08% weldability deteriorates.
• the surface quality deteriorates.
• a desired degree of alloying cannot be achieved unless the alloying treatment temperature is raised during the alloying treatment.
• the alloying treatment temperature is raised to obtain a desired degree of alloying, the ductility deteriorates and at the same time the adhesion of the alloyed plating film deteriorates. If the amount of P added is too high, the alloying temperature rises excessively. From the above, in order to achieve a desired degree of alloying, good ductility, and adhesion of the alloyed plating film, the content is made 0.08% or less.
• S 0.01% or less S segregates at grain boundaries. Or when MnS produces
• the lower limit of the S content is not particularly limited, and may be about the impurity level.
• Al 0.001% to 0.20% Al is added for the purpose of deoxidizing molten steel. However, when the content is less than 0.001%, the object is not achieved. On the other hand, if the content exceeds 0.20%, a large amount of inclusions are generated, which causes wrinkling of the steel sheet. From the above, Al is made 0.001% or more and 0.20% or less.
• Ti 0.03% or more and 0.40% or less Ti is an element necessary for increasing the strength by precipitating carbide in the steel sheet, and is also an effective element from the viewpoint of cost. However, if the addition amount is less than 0.03%, the amount of precipitates necessary for increasing the strength is insufficient, and if it exceeds 0.40%, the effect is saturated and the cost increases. Accordingly, Ti is set to 0.03% or more and 0.40% or less.
• the following elements may be added to control the strength and workability.
• Nb 0.001% to 0.2%
• V 0.001% to 0.5%
• Mo 0.01% to 0.5%
• W 0.001% to 0.2%
• Nb, V, Mo, W elements that are effective for precipitating fine carbides in a stable manner by precipitating as a composite carbide containing Ti in the steel sheet. 1 type (s) or 2 or more types are added. However, if the addition amount is less than the specified range, the effect of increasing the strength due to precipitation is insufficient, and if it exceeds the specified range, the effect is saturated and the cost is increased. Therefore, when contained, Nb is 0.001% to 0.2%, V is 0.001% to 0.5%, Mo is 0.01% to 0.5%, and W is 0.001%. 001% to 0.2%.
• B 0.0005% to 0.005% B is an effective element for improving the hardenability. However, if it is less than 0.0005%, it is difficult to obtain the quenching promoting effect. On the other hand, when it exceeds 0.005%, the effect is saturated and the cost is increased. Therefore, when B is contained, the content of B is 0.0005% or more and 0.005% or less.
• the balance is Fe and inevitable impurities.
• the average particle size of carbides present in the plating layer is 10 nm or less, and the average particle size of oxides is 50 nm or more. It is characterized by being. If the average particle size of the carbide exceeds 10 nm, the effect of suppressing crack propagation is small and the adhesion of plating during processing is deteriorated, and the hydrogen trap effect is small and the hydrogen embrittlement resistance is deteriorated. When the average particle size of the oxide is less than 50 nm, the hydrogen trap effect is small and the hydrogen embrittlement resistance deteriorates.
• the carbide is present at a rate of 5 or more and 50 or less per section. If it is less than 5 per section, the hydrogen trap effect is small and the hydrogen embrittlement resistance deteriorates. When it exceeds 50 per section, the workability of the plating film is deteriorated and the plating adhesion is lowered. Oxides are present at a rate of 5 or more and 50 or less per section. If it is less than 5 per section, the hydrogen trap effect is small and the hydrogen embrittlement resistance deteriorates. When it exceeds 50 per section, the workability of the plating film is deteriorated and the plating adhesion is lowered.
• said 1 division is a fixed area of a plating cross section, and is an area obtained by dividing a plating layer thickness (t 1 ⁇ m) and a plating layer cross section at a 1 ⁇ m interval in a direction perpendicular to the thickness direction. (T 1 ⁇ 1 ( ⁇ m 2 )).
• the carbide preferably contains Ti.
• the oxide contains Ti, Si, Mn, and Al.
• the strengthening element added in the steel is precipitated as an oxide as much as possible to soften the surface layer portion of the steel plate immediately below the plating layer and promote stress relaxation during processing.
• composition of carbides and oxides in the plating layer can be confirmed by the following method. For example, after processing a cross section of a steel sheet into a thin piece so as to include a plating layer with a focused ion beam processing apparatus (FIB), observation with a transmission electron microscope (TEM) and composition with an energy dispersive X-ray detector (EDX) Examples of methods include analysis and electron beam analysis. Moreover, as a measuring method of the average particle diameter of the carbide
• FIB focused ion beam processing apparatus
• TEM transmission electron microscope
• EDX energy dispersive X-ray detector
• the high-strength hot-dip galvanized steel sheet of the present invention has a galvanized layer having a plating adhesion amount of 20 to 120 g / m 2 on one surface of the steel sheet. If it is less than 20 g / m 2, it will be difficult to ensure corrosion resistance after coating, and if it exceeds 120 g / m 2 , plating adhesion will be reduced.
• the high-strength hot-dip galvanized steel sheet of the present invention is preferably a hot-rolled steel sheet for reasons of stretch flangeability and hole expansion.
• the finish rolling end temperature is set to 850 ° C. or higher.
• the upper limit is not particularly limited. In this invention, 1100 degrees C or less is preferable.
• the coiling temperature exceeds 540 ° C, an internal oxide is formed by an easily oxidizable element, and the Zn-Fe alloying reaction is excessively promoted during the subsequent hot dip galvanizing and alloying processes. As a result, the appearance deterioration due to the occurrence of uneven alloying, the plating adhesion of the bent portion is lowered, and the corrosion resistance of the stretch flange portion after coating is deteriorated. Further, since internal oxidation proceeds, Ti necessary for carbide generation is consumed, so that a carbide forming element such as Ti is consumed by internal oxidation, and a Ti-deficient layer is formed. Therefore, it is difficult for sufficient Ti carbide to be present in the plating layer. Therefore, the coiling temperature is 540 ° C. or lower.
• the component composition of the gas in the heating zone of the annealing furnace is H 2 ⁇ 40 vol% or more, CH 4 ⁇ 20 vol%, CO 2 ⁇ 1 vol%, the balance CO, N 2 , C x H y (x ⁇ 2, y ⁇ 4) If the amount of H 2 , CH 4 , and CO 2 is small, the surface activation effect after redox is small, and carbides and oxides formed immediately below the plating layer during the reduction annealing are difficult to be taken into the plating layer. Therefore, the carbide and oxide supply effect into the plating layer which is the most important in the present invention cannot be obtained. There is no particular limitation on the upper limit. For the remaining gas, the same effect can be obtained if these gases are mixed even in a very small amount.
• the combustion gas may be formed by mixing hydrogen gas into natural gas, industrial methane, ethane, propane gas, or the like, or coke gas generated by so-called water gas reaction may be used.
• the calorie of the coke gas changes depending on the operating rate of the mountain base and the coke oven that produce the raw material coal. Therefore, since it may be necessary to adjust components by adding hydrogen gas or the like, coke gas cannot always be used as it is.
• Furnace temperature in the heating zone of 500 ° C. or more and 1000 ° C. or less If the furnace temperature is less than 500 ° C., the steel plate surface is not sufficiently oxidized and uneven oxidation occurs, so the effect of incorporating carbide oxide into the plating layer does not progress uniformly. . If it exceeds 1000 ° C., the surface of the steel sheet is excessively oxidized, the interface between the plating layer and the steel sheet is roughened, and the plating adhesion during processing deteriorates.
• the heating temperature of the steel sheet in the heating zone is 520 ° C. or more and 650 ° C. or less and less than 520 ° C., the steel plate surface is not sufficiently oxidized, so that the effect of incorporating carbides and oxides into the plating layer is small. If it exceeds 650 ° C., it will be excessively oxidized, and the interface between the plating layer and the steel sheet will be roughened and the plating adhesion during processing will deteriorate.
• Oxidation treatment in which an oxide layer having a thickness of 6 to 60 nm is formed on the surface layer of the steel sheet In the present invention, if the thickness is less than 6 nm, the oxidation amount on the surface of the steel sheet is insufficient, so that the effect of incorporating carbide and oxide into the plating layer is small. If it exceeds 60 nm, excessive oxidation occurs, the interface between the plating layer and the steel sheet becomes rough, and the plating adhesion during processing deteriorates.
• the oxide layer in the present invention is an oxide layer mainly composed of an Fe oxide layer and substantially free of Ti (refers to an oxide layer having Ti of 0.001% or less).
• a balance N 2 include: hydrogen 5 vol% or more 50 vol%, and water vapor partial pressure (P H2 O) and hydrogen partial pressure (P H2) satisfies the equation (1). If H 2 is less than 5 vol%, the steel sheet surface is not sufficiently reduced, so that oxide remains at the interface and the corrosion resistance after coating deteriorates. If it exceeds 50 vol%, the steel sheet occludes a large amount of hydrogen, so that blisters of the plating film are generated and the surface quality is deteriorated.
• the balance and N 2 The balance and N 2.
• the water vapor partial pressure (P H2O ) and hydrogen partial pressure (P H2 ) ratio needs to satisfy the following formula (1).
• the surface is not activated and the effect of introducing carbides and oxides into the plating layer is not preferable. If it exceeds 780 ° C, Ti is selectively oxidized externally and consumed, and carbide cannot be formed.
• Control of H 2 O composition is performed by installing a bubbling device outside the annealing furnace, passing N 2 gas at a predetermined flow rate through a water tank maintained at room temperature, mixing it with N 2 gas not previously humidified, and introducing it into the furnace. carry out.
• the furnace body lower part indicates a height of 1/10 of the entire furnace body height.
• Measurement method of H 2 O and H 2 partial pressure from the dew point are not particularly limited. For example, a predetermined amount of gas is sampled, and the dew point is measured by using a dew point measuring device such as Dew Cup to determine the H 2 O partial pressure. Similarly, the H 2 partial pressure is measured with a commercially available H 2 partial pressure gauge. Alternatively, if the pressure in the atmosphere is measured, the partial pressures of H 2 O and H 2 are calculated from the concentration ratio.
• the hot dip galvanized steel sheet of the present invention can be made into an alloyed hot dip galvanized steel sheet by subjecting it to an alloying treatment after the hot dip plating process.
• the steel sheet is heated to a temperature of 450 ° C. or more and 510 ° C. or less to be alloyed, and cooled to 400 ° C. at 20 ° C./s or less.
• the Fe content in the plating layer thus obtained is 7 to 15%. If the Fe content is less than 7%, not only a uniform surface appearance cannot be obtained due to the occurrence of unevenness in alloying, but also the Zn—Fe alloying reaction is insufficient, so that a soft ⁇ phase is formed thick on the plating surface layer.
• the flaking that causes the plating layer to flake off during bending is caused.
• the Zn—Fe alloying reaction proceeds excessively, a brittle ⁇ phase is formed in the vicinity of the interface between the plating layer and the steel sheet, and the plating adhesion deteriorates.
• the alloying temperature is less than 450 ° C., the alloying reaction does not proceed sufficiently.
• it exceeds 510 ° C. the ⁇ phase is formed thick and the plating adhesion of the processed part is deteriorated.
• CGL coke gas whose composition is adjusted to a predetermined component in the heating zone is burned and oxidized, and then the furnace atmosphere, water vapor partial pressure, hydrogen partial pressure, and maximum steel plate temperature in the soaking zone are shown in Table 2.
• the steel sheet was subjected to reduction treatment under the conditions shown in FIG. Note that the control of the dew point in the atmosphere, N 2 by heating water tank installed in the gas line, wet N 2 gas flows in advance separately installed piping was, wet N H 2 gas into two gas Were mixed and introduced into the furnace to control the dew point of the atmospheric gas.
• the H 2 concentration in the atmosphere was controlled by adjusting the amount of H 2 gas introduced into the N 2 gas with a gas valve.
• the plating adhesion amount at this time is 45 g / m 2 (plating layer thickness t 1 : 6 ⁇ m), 70 g / m 2 (plating layer thickness t 1 : 10 ⁇ m), 140 g / m 2 (plating layer thickness) by gas wiping. (T 1 : 20 ⁇ m).
• the alloyed hot dip galvanized steel sheet was subjected to an alloying treatment after the hot dip galvanizing treatment.
• the corrosion resistance after painting of the processed part was investigated.
• the measurement method and evaluation criteria are shown below.
• the size and composition of carbides and oxides in the plating layer were measured by observing and analyzing FIB-processed plated thin film samples with TEM-EDX and EELS.
• species was identified and analyzed by the X ray diffraction method.
• Appearance was determined as good appearance ( ⁇ ) when there was no plating surface appearance defect such as non-plating or alloying unevenness, and when it was present, it was judged as poor appearance ( ⁇ ).
• a test piece having a hole punched out with a clearance of 12.5% by a punch of 10 mm ⁇ at the center of a steel plate cut into a 130 mm square is pushed up by a 60 ° conical punch from the opposite direction on the burr side of the punched hole, and cracks are generated.
• the hole diameter d (mm) at the time of penetrating the steel plate was measured, and the hole expansion rate ⁇ was calculated from the following equation.
• ⁇ (%) [(d ⁇ 10) / 10] ⁇ 100 ⁇ Plating adhesion of bent part>
• the plating adhesion of the hot dip galvanized steel sheet not subjected to the alloying treatment was evaluated by the following evaluation after the steel sheet was bent at 180 °, the outside of the bent portion was peeled off with tape, the presence or absence of peeling of the plated layer was visually determined.
• Plating layer is peeled
• the plating adhesion of the galvannealed steel sheet was evaluated by the following powdering test.
• the amount of plating peeling was determined as the amount of plating peeling.
• the amount of plating peeling obtained in the above-mentioned powdering test is good ( ⁇ ) for rank 1 in light of the following criteria ( ⁇ ), 2 is generally good ( ⁇ ), and 3 Evaluated as defective (x). ⁇ and ⁇ are acceptable.
• Plating peeling amount Rank 0 less than 3000: 1 (good ( ⁇ )) 3000 or more and less than ⁇ 6000: 2 (good ( ⁇ )) 6000 or more: 3 (defect (x)) ⁇ Hydrogen embrittlement resistance>
• a strip test piece of 150 mm ⁇ 30 mm is bent at a bending radius of 5 mm, a water-resistant strain gauge is attached to the surface, and immersed in 0.5 mol / L sulfuric acid.
• a current density of 0.1 mA / cm 2 is applied to the test piece.
• the electrolysis was performed by energizing the test piece, hydrogen was allowed to enter the test piece, and the occurrence of cracks after 2 hours of energization was evaluated according to the following criteria.
• the examples of the present invention are the appearance, workability, plating adhesion of the bent portion, hydrogen embrittlement resistance, and coating of the stretch flange processed portion. Good post-corrosion resistance ( ⁇ ).
• the comparative example which does not satisfy the scope of the present invention has a low evaluation.

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