EP4667607A1 - Tôle d'acier et procédé de fabrication de tôle d'acier - Google Patents

Tôle d'acier et procédé de fabrication de tôle d'acier

Info

Publication number
EP4667607A1
EP4667607A1 EP24779731.9A EP24779731A EP4667607A1 EP 4667607 A1 EP4667607 A1 EP 4667607A1 EP 24779731 A EP24779731 A EP 24779731A EP 4667607 A1 EP4667607 A1 EP 4667607A1
Authority
EP
European Patent Office
Prior art keywords
mass
steel sheet
less
carbon concentration
reduction treatment
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
EP24779731.9A
Other languages
German (de)
English (en)
Inventor
Shuya MAEKAWA
Ryosuke OTOMO
Hiroshi Irie
Shoichi Hirai
Kentaro KIGUCHI
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.)
Kobe Steel Ltd
Original Assignee
Kobe Steel Ltd
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
Priority claimed from JP2024022770A external-priority patent/JP2024144148A/ja
Application filed by Kobe Steel Ltd filed Critical Kobe Steel Ltd
Publication of EP4667607A1 publication Critical patent/EP4667607A1/fr
Pending legal-status Critical Current

Links

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
    • 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
    • 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
    • C21D3/00—Diffusion processes for extraction of non-metals; Furnaces therefor
    • C21D3/02—Extraction of non-metals
    • C21D3/04—Decarburising
    • 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 of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties of ferrous metals or ferrous alloys 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
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/08—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
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
    • 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
    • C23C2/04—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
    • C23C2/04—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
    • C23C2/12—Aluminium or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/26—After-treatment
    • C23C2/28—Thermal after-treatment, e.g. treatment in oil bath
    • 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
    • C21D2211/004—Dispersions; Precipitations

Definitions

  • Si or Mn is effective.
  • Si and Mn are oxidized even in a reducing atmosphere in which oxidation of Fe does not occur, and oxides of Si and Mn are formed on the outermost surface of a steel sheet.
  • the oxide of Si or Mn lowers wettability between molten zinc and a base steel sheet, for example, during a zinc-based plating treatment, and thus there has been a problem that bare spots frequently occur or plating adhesion is poor in a steel sheet with addition of Si or Mn.
  • Patent Document 1 discloses a method for manufacturing a high-strength galvanized steel sheet superior in plating adhesion, workability, and fatigue resistance properties, in which a steel sheet is subjected to an oxidation treatment, and then reduction-annealing.
  • the oxidation treatment in a first stage, the steel sheet is heated at a temperature of 400 to 750°C in an atmosphere having an O 2 concentration of 1000 ppm by volume or more and an H 2 O concentration of 1000 ppm by volume or more, and, in a second stage, the steel sheet is heated at a temperature of 600 to 850°C in an atmosphere having an O 2 concentration of less than 1000 ppm by volume and an H 2 O concentration of 1000 ppm by volume or more.
  • the steel sheet in a heating zone, is heated at a heating rate of 0.1°C/sec or more to a temperature of 650 to 900°C in an atmosphere having an H 2 concentration of 5 to 30% by volume and an H 2 O concentration of 10 to 1000 ppm by volume with a balance of N 2 and inevitable impurities, and thereafter, in a soaking zone, the steel sheet is soaked and held for 10 to 300 seconds with a temperature variation in the soaking zone of ⁇ 20°C or less in an atmosphere having an H 2 concentration of 5 to 30% by volume and an H 2 O concentration of 500 to 5000 ppm by volume with a balance of N 2 and inevitable impurities.
  • Patent Document 1 JP 2017-166057 A
  • a steel sheet In manufacturing an automobile component, a steel sheet may be bent into a component shape.
  • a high-strength steel sheet having a strength of, for example, 980 MPa or more, or 1180 MPa or more has a problem that it is difficult to favorably perform bending thereon to obtain a desired component shape, that is, it is difficult to secure superior bendability.
  • improvement in the bendability of the plated steel sheet has not been studied.
  • the present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a steel sheet having high strength, capable of contributing to weight reduction of a vehicle body, and exhibiting superior bendability, and a method by which the steel sheet can be easily manufactured.
  • Aspect 1 of the present invention is
  • Aspect 2 of the present invention is
  • Aspect 3 of the present invention is
  • Aspect 4 of the present invention is the steel sheet according to any one of Aspects 1 to 3, wherein a component composition satisfies:
  • Aspect 6 of the present invention is the method for manufacturing a steel sheet according to Aspect 5, wherein an attainment temperature in the first reduction treatment and the second reduction treatment is 800 to 920°C.
  • a steel sheet having high strength capable of contributing to weight reduction of a vehicle body, and exhibiting superior bendability, and a method for manufacturing the steel sheet.
  • the present inventors intensively studied to obtain a steel sheet exhibiting superior bendability during a bending work even with high strength.
  • the present inventors have found that by providing a decarburized layer within a prescribed range in the steel sheet surface layer, superior bendability can be obtained with retention of high strength.
  • the present inventors have found that controlling conditions for annealing a steel sheet (a substrate) can contribute to the formation of a decarburized layer within a prescribed range capable of achieving both high strength and superior bendability on a steel sheet surface layer.
  • the steel sheet of the present embodiment will be first described.
  • the position where the carbon concentration (mass%) is 50% of the bulk carbon concentration is in a region of 0.20% or more of the sheet thickness from the steel sheet surface.
  • the aforementioned positions relate to the thickness of the decarburized layer which contributes to bendability.
  • the position where the carbon concentration (mass%) is 50% of the bulk carbon concentration may be in a region of 0.5% or more, or 1.0% or more of the sheet thickness from the steel sheet surface.
  • the position where the carbon concentration (mass%) is 90% of the bulk carbon concentration in the sheet thickness direction is in a region of 8.0% or less of the sheet thickness from the steel sheet surface.
  • the bendability is improved, but the strength tends to decrease.
  • the position where the carbon concentration (mass%) is 90% of the bulk carbon concentration may be 6.0% or less of the sheet thickness from the steel sheet surface.
  • the present inventors have first found that there is a region having a significantly high carbon concentration in the steel sheet surface layer, and this is a cause of deterioration in bendability.
  • the present inventors studied conditions for manufacturing a steel sheet, and have found that when decarburization of the steel sheet surface layer is promoted to control the carbon concentration of the steel sheet surface layer, specifically, when the maximum value of the carbon concentration (mass%) in a region up to 20 ⁇ m from the steel sheet surface in the sheet thickness direction is controlled to less than 70% of the bulk carbon concentration, superior bendability can be easily obtained.
  • the maximum value of the carbon concentration is preferably 65% or less of the bulk carbon concentration, and more preferably 60% or less of the bulk carbon concentration.
  • the surface layer decarburization amount per millimeter of the sheet thickness on one surface of the steel sheet is controlled to 0.045 mol/m 2 or less, preferably 0.035 mol/m 2 or less, whereby a tensile strength as high as 980 MPa or more, particularly 1180 MPa or more can be secured.
  • the surface layer decarburization amount per millimeter of the sheet thickness is more preferably 0.030 mol/m 2 or less, and even more preferably 0.025 mol/m 2 or less.
  • the steel sheet according to the present embodiment is merely required to satisfy at least one of the above (I) and (II), and preferably satisfies the above (I), more preferably satisfies both the above (I) and (II).
  • the "steel sheet surface” refers to a surface of a steel sheet in the case of a steel sheet obtained by performing annealing on a cold rolled steel sheet, and refers to a position of the interface between a plating layer and a base steel sheet in the case of a plated steel sheet.
  • the position of the interface between the plating layer and the base steel sheet refers to a point where Zn constituting the plating layer is not detected (the analysis value of Zn becomes 0) when Zn is analyzed in the thickness direction of the plating layer from the surface of the plating layer by GD-OES performed in Examples described later, and this point is taken as the start point of the distance (depth) from the steel sheet surface.
  • the steel sheet according to the present embodiment exhibits superior bendability in a bending work even with high strength.
  • a tensile strength TS of 980 MPa or more, preferably 1180 MPa or more is exhibited, for example.
  • the steel sheet according to the present embodiment exhibits superior bendability with a limit R/t of less than 2.5 when a bending test described in Examples described later is performed.
  • the sheet thickness of the steel sheet according to the present embodiment is not limited.
  • the sheet thickness of the steel sheet according to the present embodiment (the sheet thickness of a base steel sheet in the case of a plated steel sheet) may be, for example, 0.4 mm or more and 4 mm or less.
  • the steel sheet according to the present embodiment can have, for example, a Si content of more than 0.5 mass% in the component composition.
  • the Si content is more preferably 1.0 mass% or more, even more preferably 1.1 mass% or more, and still even more preferably 1.2 mass% or more.
  • the upper limit of the Si content may be, for example, 3.0 mass%.
  • the component composition of the steel sheet satisfies:
  • C is an element effective for improving the strength of the steel sheet, and is a particularly effective reinforcing element for finally ensuring the tensile strength of the steel sheet of 980 MPa or more, or 1180 MPa or more, by being contained in the steel together with Si, and as necessary also with Mn. Furthermore, C is also an element necessary for securing retained austenite and improving the workability. To allow such an action to be effectively exerted, the C content is preferably 0.08 mass% or more, more preferably 0.11 mass% or more, and even more preferably 0.13 mass% or more.
  • the C content is larger, but when the C content is excessively large, corrosion resistance, spot weldability, and workability may be deteriorated. Therefore, the C content is preferably 0.30 mass% or less, more preferably 0.25 mass% or less, and even more preferably 0.23 mass% or less.
  • Mn is also an inexpensive steel reinforcing element, similarly to Si, and is effective for improving the strength of the steel sheet.
  • Mn is a particularly effective reinforcing element for finally ensuring the tensile strength of the steel sheet of 980 MPa or more, or 1180 MPa or more, by being contained in the steel together with Si, and as necessary also with C.
  • Mn is also an element that stabilizes austenite and contributes to improvement of the workability of the steel sheet due to the generation of retained austenite.
  • the Mn content is preferably 1.5 mass% or more, more preferably 1.8 mass% or more, and even more preferably 2.0 mass% or more.
  • the Mn content is preferably 3.0 mass% or less, more preferably 2.8 mass% or less, and even more preferably 2.7 mass% or less.
  • Si is an inexpensive steel reinforcing element, and hardly affects the workability of the steel sheet.
  • Si is an element capable of suppressing the decomposition of retained austenite, which is useful for improving the workability of the steel sheet, into carbides.
  • the Si content is more than 0.5 mass%, preferably 1.0 mass% or more, more preferably 1.1 mass% or more, and even more preferably 1.2 mass% or more.
  • the upper limit of the Si content is not particularly limited, but when the Si content is excessively large, a solid-solution strengthening action by Si is remarkable, leading to the risk that the rolling load increases.
  • the Si content is preferably 3.0 mass% or less, more preferably 2.7 mass% or less, and even more preferably 2.5 mass% or less.
  • Cr is an element effective for the delayed fracture resistance of the steel sheet similarly to B and Ti
  • Cr can be contained in an amount at which the workability, such as strength or elongation, of the steel sheet is not affected.
  • the Cr content may be 0 mass%, but to allow these actions to be effectively exerted, the Cr content is preferably more than 0 mass%, more preferably 0.003 mass% or more, and even more preferably 0.01 mass% or more.
  • the Cr content is preferably 1.0 mass% or less, more preferably 0.8 mass% or less, and even more preferably 0.6 mass% or less.
  • the P content is an element inevitably present as an impurity element.
  • the P content is preferably controlled to be 0.1 mass% or less, more preferably 0.08 mass% or less, and even more preferably 0.05 mass% or less.
  • S is an element inevitably present as an impurity element.
  • steel inevitably contains S in an amount of about 0.0005 mass%.
  • the S content is preferably controlled to be 0.05 mass% or less, more preferably 0.01 mass% or less, and even more preferably 0.005 mass% or less.
  • N is an element inevitably present as an impurity element.
  • a nitride may be formed to deteriorate the workability of the steel sheet.
  • the steel sheet contains B for improving the hardenability, N bonds with B to form a BN precipitate, and inhibits the hardenability improving action of B. Therefore, the N content is preferably controlled to be 0.01 mass% or less, more preferably 0.008 mass% or less, and even more preferably 0.005 mass% or less.
  • the balance is Fe and inevitable impurities. It is permitted to mix, as inevitable impurities, trace elements (e.g., As, Sb, and Sn) incorporated according to the conditions of raw materials, materials, manufacturing facilities, etc. It is usually preferable with P, S and N described above that the content is as small as possible, and therefore, these can be called inevitable impurities.
  • trace elements e.g., As, Sb, and Sn
  • P, S and N e.g., As, Sb, and Sn
  • optional components can be further contained as long as the strength and sufficient bendability are not impaired.
  • the optional components include Cu, Ni, Ti, Nb, V, and B. These optional components will be described below.
  • Cu is an element that is effective for improving the strength of the steel sheet, has the action of suppressing the generation of hydrogen due to the corrosion of the steel sheet, and improves the corrosion resistance of the steel sheet.
  • Cu also has an action of promoting the production of iron oxide.
  • the Cu content is preferably more than 0 mass%, more preferably 0.003 mass% or more, and even more preferably 0.05 mass% or more. From the viewpoint of the workability of the steel sheet, the Cu content is preferably 1.0 mass% or less, more preferably 0.8 mass% or less, and even more preferably 0.5 mass% or less.
  • Ni preferably more than 0 mass% and 1.0 mass% or less
  • Ni is an element that is effective for improving the strength of the steel sheet, has the action of suppressing the generation of hydrogen due to the corrosion of the steel sheet, and improves the corrosion resistance of the steel sheet.
  • Ni also has an action of promoting the production of iron oxide similarly to Cr and Cu.
  • the Ni content is preferably more than 0 mass%, more preferably 0.003 mass% or more, and even more preferably 0.05 mass% or more. From the viewpoint of ensuring the workability of the steel sheet, the Ni content is preferably 1.0 mass% or less, more preferably 0.8 mass% or less, and even more preferably 0.5 mass% or less.
  • Ti is an element that is effective for improving the strength of the steel sheet, has the action of suppressing the generation of hydrogen due to the corrosion of the steel sheet, and improves the corrosion resistance of the steel sheet. Ti also has the action of promoting the production of iron oxide similarly to Cr, Cu, and Ni. In addition, because Ti is an element effective for the delayed fracture resistance of the steel sheet similarly to B and Cr, Ti may be contained in an amount at which the workability, such as strength or elongation, of the steel sheet is not affected. To allow these actions to be effectively exerted, the Ti content is preferably more than 0 mass%, more preferably 0.003 mass% or more, and even more preferably 0.05 mass% or more. From the viewpoint of ensuring the workability of the steel sheet, the Ti content is preferably 0.15 mass% or less, more preferably 0.12 mass% or less, and even more preferably 0.10 mass% or less.
  • the Nb is an element that is effective for improving the strength of the steel sheet, and acts on improving the toughness of the steel sheet by miniaturizing austenite grains after quenching.
  • the Nb content is preferably more than 0 mass%, more preferably 0.003 mass% or more, and even more preferably 0.005 mass% or more.
  • the Nb content is preferably 0.15 mass% or less, more preferably 0.12 mass% or less, and even more preferably 0.10 mass% or less.
  • V is also an element that is effective for improving the strength of the steel sheet, and acts on improving the toughness of the steel sheet by miniaturizing austenite grains after quenching.
  • the V content is preferably more than 0 mass%, more preferably 0.003 mass% or more, and even more preferably 0.005 mass% or more.
  • the V content is preferably 0.15 mass% or less, more preferably 0.12 mass% or less, and even more preferably 0.10 mass% or less.
  • B is an element useful for improving the hardenability and weldability of the steel sheet.
  • B is an element effective for the delayed fracture resistance of the steel sheet similarly to Ti and Cr, B may be contained in an amount at which the workability, such as strength or elongation, of the steel sheet is not affected.
  • the B content is preferably more than 0 mass%, more preferably 0.0002 mass% or more, even more preferably 0.0003 mass% or more, and particularly preferably 0.0004 mass% or more.
  • the B content is preferably 0.005 mass% or less, more preferably 0.004 mass% or less, and even more preferably 0.003 mass% or less.
  • the steel sheet examples include a cold rolled steel sheet and a plated steel sheet.
  • the type of the plated steel sheet is not limited, and may be, for example, a zinc-based plated steel sheet provided with zinc-based plating, such as Al-Zn plating, Ni-Zn plating, Fe-Zn plating, Cr-Zn plating, or Mg-Zn plating.
  • Specific examples of the zinc-based plated steel sheet include a galvanized steel sheet (GI), an alloyed galvanized steel sheet (GA), and an electrogalvanized steel sheet (EG).
  • an Fe oxide layer is formed on the surface of the steel sheet.
  • a reduced Fe layer capable of favorably forming, for example, a plating layer is formed on the steel sheet surface layer while a decarburized layer is formed.
  • the decarburization amount becomes excessive, and the strength may decrease.
  • decarburization is performed once, but carbon is re-diffused (recarburized) into the decarburized part in the latter half of the reduction treatment, so that the bendability is not improved.
  • the present inventors conducted studies, and resultantly have found that the decarburized state of the steel sheet surface layer portion, where both high strength and superior bendability can be attained, can be easily ensured by performing the oxidation treatment as described above, determining the dew point range of the first reduction treatment and that of the second reduction treatment in the reduction treatment, and making the dew point of the second reduction treatment higher than the dew point of the first reduction treatment.
  • the oxidation treatment and the reduction treatment will be described.
  • the oxidation treatment is performed under the condition of an oxygen concentration of 0.1 to 2%.
  • the oxidation treatment can be performed even under the condition of an oxygen concentration of 0.0%, but in the case of obtaining a plated steel sheet, the oxygen concentration is preferably set to 0.1% or more from the viewpoint of obtaining a superior plating appearance.
  • the oxygen concentration is more preferably 0.15% or more, and even more preferably 0.20% or more.
  • pick-up which is a phenomenon in which an oxide scale adheres to a furnace roll due to excessive oxidation and a pressing mark occurs on a steel sheet. From the viewpoint of suppressing the occurrence of this defect, the oxygen concentration is set to 2% or less.
  • the oxygen concentration is more preferably 1.7% or less, and even more preferably 1.5% or less.
  • concentration of elements other than oxygen is not particularly limited, and examples thereof include a gas atmosphere containing CO 2 , N 2 , H 2 O, and other inevitable impurities together with oxygen having the above concentration.
  • the oxidation treatment can be performed in a combustion gas such as cokes oven gas (COG) or liquefied petroleum gas (LPG) in, for example, a direct fired furnace (DFF)-type annealing furnace or the like under a gas atmosphere in which a concentration of unburned O 2 is controlled.
  • COG cokes oven gas
  • LPG liquefied petroleum gas
  • DFF direct fired furnace
  • the oxidation treatment is performed under the condition of an attainment temperature of 650 to 750°C.
  • the oxidation treatment may involve heating the steel sheet to an attainment temperature within a range of 650 to 750°C in an oxidation heating zone in a DFF-type annealing furnace.
  • the attainment temperature By setting the attainment temperature to 750°C or lower, it is possible to suppress a reaction particularly between SiO 2 on the steel sheet surface in the vicinity of the edge in the width direction of the steel sheet and FeO generated by the oxidation treatment.
  • the steel sheet according to the present embodiment is a plated steel sheet, good plating adhesion can be obtained.
  • the "attainment temperature" at the time of heating in the oxidation treatment means a maximum attainment sheet temperature of the steel sheet whose heating is controlled in an oxidation heating zone.
  • the attainment temperature in the oxidation treatment is preferably 730°C or lower, more preferably 720°C or lower, and even more preferably 700°C or lower.
  • the steel sheet temperature in the oxidation treatment is set to 650°C or higher from the viewpoint of forming an Fe oxide layer in the gas atmosphere.
  • the steel sheet temperature in the oxidation treatment is preferably 670°C or higher.
  • the temperature rise time in the oxidation treatment is not particularly limited, and may be adjusted such that, for example, a firelite layer that adversely affects the platability is not formed by the oxidation treatment due to an excessively long temperature rise time.
  • the temperature rise time in the oxidation treatment may be appropriately adjusted in consideration of the conditions of hot rolling (particularly the winding temperature), the annealing conditions before pickling, the pickling conditions, the temperature of the steel sheet during heating in the oxidation treatment, etc.
  • the temperature rise time in the oxidation treatment is preferably 10 seconds or more, and more preferably 15 seconds or more, for example.
  • the temperature rise time in the oxidation treatment is preferably 120 seconds or less, and more preferably 90 seconds or less, for example.
  • the mode of the oxidation treatment is not limited thereto, and the oxidation treatment may be performed by raising the temperature up to the attainment temperature and holding the temperature at the attainment temperature.
  • the reduction treatment a desired decarburized layer is formed on the steel sheet surface layer.
  • a reduced Fe layer capable of favorably forming a plating layer is formed, for example.
  • the reduction treatment is performed through a first reduction treatment having a dew point of -35 to -15°C, and subsequently through a second reduction treatment having a dew point being -25 to 0°C and being higher than the dew point of the first reduction treatment.
  • first reduction treatment having a dew point of -35 to -15°C
  • a second reduction treatment having a dew point being -25 to 0°C and being higher than the dew point of the first reduction treatment.
  • the dew point is set within a range of -35 to - 15°C.
  • the dew point is higher than -15°C, decarburization easily proceeds more than necessary, and the strength is easily deteriorated.
  • the reduction treatment is less likely to proceed, and a defect called a pickup, in which iron oxide generated by the oxidation treatment adheres to a roll and causes a pressing mark on the steel sheet, is prone to occur. Therefore, the dew point is set to -15°C or lower.
  • the dew point is preferably -20°C or lower.
  • the dew point in the first reduction treatment is set to -35°C or higher.
  • the dew point is preferably -30°C or higher.
  • the dew point may satisfy the fact that the dew point in the atmosphere at the central portion of the front stage of the reduction zone where the first reduction treatment is performed is within the above range.
  • the control of the dew point in the first reduction treatment and the second reduction treatment which is described later can be performed by, for example, a method in which a water vapor gas is charged and mixed with an atmospheric gas contained in a furnace, or a method in which an atmospheric gas is bubbled and water vapor is mixed.
  • the atmosphere of the first reduction treatment may be an atmosphere that satisfies the dew point described above and contains N 2 , H 2 , CO, H 2 O, O 2 , and other inevitable impurities.
  • the attainment temperature of the steel sheet reaches 800°C in the atmosphere described above, and then, the steel sheet is held in a temperature range of 800 to 920°C, for 60 to 240 seconds, for example.
  • the term "hold" includes not only a case where the temperature is kept at a certain fixed temperature, but also a case where the temperature varies within the temperature range described above.
  • Fig. 1-1 Nos. 1 to 16
  • Fig. 1-2 Nos. 17 to 22
  • Fig. 1-1 and 1-2 are graphs created using Examples described later, and are graphs showing the relationship between the dew point at the center of the soaking zone during the second reduction treatment and R/t. From Figs. 1-1 and 1-2 , it is found that the dew point in the second reduction treatment needs to be set to -25°C or higher in order to achieve superior bendability with a R/t of less than 2.5 as indicated by arrows in the diagrams.
  • Fig. 2-1 Nos. 1 to 16
  • Fig. 2-2 Nos.
  • FIGs. 17 to 22 are graphs created using Examples described later, and are graphs showing the relationship between the dew point at the center of the soaking zone during the second reduction treatment and the tensile strength TS. From Figs. 2-1 and 2-2 , it is found that when the dew point is set to 0°C or lower, high strength with a tensile strength TS of 980 MPa or more, or 1180 MPa or more can be ensured.
  • the dew point in the second reduction treatment is preferably -15°C or lower.
  • the atmosphere of the second reduction treatment may be an atmosphere that satisfies the dew point described above and contains N 2 , H 2 , CO, H 2 O, O 2 , and other inevitable impurities.
  • the steel sheet is held in the atmosphere described above within a temperature range in which the attainment temperature of the steel sheet is 800 to 920°C for 60 to 240 seconds, for example.
  • the term "hold" includes not only a case where the temperature is kept at a certain fixed temperature, but also a case where the temperature varies within the temperature range described above.
  • the first reduction treatment and the second reduction treatment are merely required to be divided into atmospheres differing in dew point as described above, and their specific modes are not limited.
  • a front region for performing the first reduction treatment and a rear region for performing the second reduction treatment may be separated by installing a partition wall having an opening area ratio of 20% or less, for example.
  • a step such as a holding step of holding at least any one of the conditions (dew point, heating temperature) of the first reduction treatment, for example, a cooling step of cooling to a temperature between the heating temperature of the first reduction treatment and room temperature may also be provided as long as there is no adverse effect on ensuring the decarburized state of the steel sheet according to the present embodiment.
  • the second reduction treatment is performed subsequently to the first reduction treatment.
  • the oxidation treatment and the reduction treatment may be performed using any publicly-known single facility or multiple facilities.
  • a facility of a continuous galvanizing line CGL
  • an oxidation treatment and a reduction treatment by an oxidation-reduction method and for example, a galvanizing treatment and an alloying treatment when a zinc-plated steel sheet is manufactured as the steel sheet, for example, can be continuously performed in a tandem manufacturing line.
  • the oxidation treatment and the reduction treatment by the oxidation-reduction method may be performed using, for example, an annealing furnace in a DFF-type continuous galvanizing line.
  • the oxidation treatment may be performed in a heating zone in a DFF-type annealing furnace.
  • the reduction treatment may be performed, for example, in a soaking zone in a DFF-type annealing furnace.
  • the method for producing the steel sheet (substrate) to be subjected to annealing is not particularly limited.
  • the steel sheet (substrate) to be subjected to annealing can be obtained by smelting and casting steel by a method usually performed to obtain a steel slab, and subjecting the steel slab to a rolling step (hot rolling, cold rolling) by a method usually performed.
  • the method for forming a galvanized layer on the surface of the annealed steel sheet is not particularly limited, and a publicly-known method can be appropriately used.
  • the base material after the annealing step is immersed in a plating bath.
  • the plating deposition amount it is preferable to control the plating deposition amount to, for example, 20 g/m 2 or more and 200 g/m 2 or less by, for example, gas wiping.
  • binary or higher alloy plating containing Zn can be used for the plating bath.
  • the binary or higher alloy plating containing Zn include Al-Zn plating, Fe-Zn plating, Ni-Zn plating, Cr-Zn plating, and Mg-Zn plating.
  • the plating may be performed by using a plating bath containing components other than zinc at a concentration of, for example, 0.01 mass% or more and 0.5 mass% or less and immersing a substrate in the plating bath at, for example, a temperature of 300°C or more and 600°C or less for 1 second or more and 30 seconds or less, for example.
  • the alloying treatment is also not particularly limited, and a publicly-known method can be appropriately used.
  • the alloying treatment may be performed, for example, by reheating at an alloying temperature of 470°C or more and 600°C or less for 1 second or more and 100 seconds or less.
  • a substrate was prepared in which the component composition was a bulk carbon concentration, that is, a C content of the steel sheet (substrate) was 0.22 mass%, the Si content was 1.7 mass%, the Mn content was 2.0 mass%, the Cr content was 0.5 mass%, the Al content was 0.04 mass%, and the balance was Fe and inevitable impurities (note that the "inevitable impurities" referred to here included P, S, and N in amounts within the above-described ranges), the structure was ferrite + pearlite, and the strength was 700 to 800 MPa.
  • the component composition was a bulk carbon concentration, that is, a C content of the steel sheet (substrate) was 0.22 mass%, the Si content was 1.7 mass%, the Mn content was 2.0 mass%, the Cr content was 0.5 mass%, the Al content was 0.04 mass%, and the balance was Fe and inevitable impurities (note that the "inevitable impurities" referred to here included P, S, and N in amounts within the above-described range
  • a substrate was prepared in which the bulk carbon concentration was 0.13 mass% (0.13 mass% C), the Si content was 0.9 mass%, the Mn content was 2.3 mass%, the Cr content was 0.57 mass%, the Al content was 0.02 mass%, the balance was Fe and inevitable impurities (note that the "inevitable impurities" referred to here included P, S, and N in amounts within the above-described ranges), the structure was ferrite + pearlite, and the strength was 700 to 800 MPa. In Nos.
  • a substrate was prepared in which the bulk carbon concentration was 0.21 mass% (0.21 mass% C), the Si content was 1.8 mass%, the Mn content was 2.3 mass%, the Al content was 0.45 mass%, and the balance was Fe and inevitable impurities (note that the "inevitable impurities" referred to here included P, S, and N in amounts within the above-described ranges), the structure was ferrite + pearlite, and the strength was 600 to 700 MPa.
  • the samples for annealing described above were subjected to an oxidation treatment and a reduction treatment using an actual machine.
  • the oxidation treatment was performed at the oxygen concentration and the attainment temperature shown in Table 1, and then the first reduction treatment (heating zone) and the second reduction treatment (soaking zone) shown in Table 1 were performed in this order under each condition shown in Table 1 (attainment temperature, dew point).
  • the conditions of the "first reduction zone” indicate the conditions of the first reduction treatment
  • the conditions of the "second reduction zone” indicate the conditions of the second reduction treatment.
  • the steel sheet after the second reduction treatment was cooled to 460°C, and then immersed in an Al-Zn plating bath containing 0.08 to 0.13 mass% of Al (Al was effective Al%, and the plating bath temperature was 460 to 480°C) to perform zinc plating.
  • the deposition amount of plating was controlled to 40 g/m 2 or more and 90 g/m 2 or less by gas wiping, and then an alloying treatment was performed at 480 to 490°C for 20 to 30 seconds, affording an alloyed galvanized steel sheet.
  • the obtained alloyed galvanized steel sheet was evaluated as follows.
  • the carbon profile was measured by glow discharge optical emission spectrometry (GD-OES), and the decarburization behavior was examined.
  • a material having a size of 50 mm ⁇ 40 mm ⁇ plate thickness or 30 mm ⁇ 30 mm ⁇ plate thickness was taken. Thereafter, degreasing was performed in accordance with a conventional method, whereby a sample was prepared. Then, using this sample, the concentration in mass% of each element was measured by GD-OES under the following conditions.
  • the surface of the sample on which the plating was formed was subjected to GD-OES measurement up to a depth of 150 ⁇ m in the sheet thickness direction.
  • the sputtering rate of the above device was substantially constant, the sputter crater depth of the sample after the analysis was measured, and the measured value (sputtering depth) was plotted in the horizontal axis.
  • the emission intensity I i was measured using two or more reference samples with known W i , and the slope a and the intercept b of the above Equation (1) were determined, and thus a calibration curve was prepared in which the horizontal axis was the emission intensity and the vertical axis was the sputtering weight.
  • the reference samples used are shown in Table 2 below.
  • the sputtering weight was determined from the emission intensity of each target element, and their weight ratios were converted into concentrations.
  • the calibration curve used for the conversion of the O concentration was corrected using SiO 2 such that the concentration ratio of Si and O was 1 : 2.
  • a carbon profile was obtained using the analysis result on carbon.
  • Fig. 3 illustrates No. 2, which is a comparative example, and No. 10, which is an example of the present invention.
  • the carbon profiles of both the materials each has a peak of the carbon concentration within 20 ⁇ m of the surface layer (specifically, in the internal oxide layer), but the carbon concentration is higher than the bulk carbon concentration in the comparative example, whereas the carbon concentration is sufficiently lower than the bulk carbon concentration in the present invention example.
  • the position where the carbon concentration (mass%) was 50% of the bulk carbon concentration, the position where the carbon concentration (mass%) was 90% of the bulk carbon concentration, and the maximum value of the carbon concentration (mass%) in the region up to 20 ⁇ m from the steel sheet surface were determined.
  • the bulk carbon concentration was corrected such that the carbon concentration at a sufficiently deep position (120 to 150 ⁇ m) measured by GD-OES equaled a value obtained by ordinary steel analysis, and then the corrected value was used for analysis. For example, when the steel analysis value was 0.22% and the analysis value by GD-OES was 0.25%, the analysis value by GD-OES was multiplied by 0.22/0.25 and then used for analysis.
  • the surface layer decarburization amount per millimeter of the sheet thickness on one surface of the steel sheet was determined as follows. First, the amount of desorbed carbon was determined from the difference between the bulk carbon concentration and the carbon concentration profile of the steel sheet (after decarburization). That is, for a 1m 2 steel sheet, the total decarburization amount was determined from the volume (m 3 ) of iron in the decarburized part ⁇ the density (specific gravity) of iron (7.87 ⁇ 10 6 g/m 3 ) ⁇ the ratio of decarburized carbon accounting for in the iron in the decarburized part/the atomic weight (g/mol) of carbon. Then, the total decarburization amount was divided by the sheet thickness, whereby the surface layer decarburization amount (mol/m 2 ) per millimeter of the sheet thickness of one steel sheet surface was determined.
  • the tensile strength (TS) was measured in accordance with the method specified in JIS Z 2241:2011 by taking a JIS No. 5 tensile test piece from a steel sheet such that a direction perpendicular to the rolling direction of the steel sheet was the longitudinal direction. Then, a case where the tensile strength (TS) was 980 MPa or more was evaluated as being high in strength (preferably, a case where the TS was 1180 MPa or more was evaluated as being higher in strength), whereas a case where the TS was less than 980 MPa was evaluated as being poor in strength.
  • Nos. 1 to 4 and 22 had no surface layer portion of a steel sheet defined in the present embodiment, and were inferior in bendability.
  • Nos. 5 to 21 each had a surface layer portion of a steel sheet defined in the present embodiment, and were able to achieve both high strength and superior bendability.
  • the oxidation treatment is preferably performed under prescribed conditions in the manufacturing process as in Nos. 9 to 21.
  • the disclosure in this description may include the following aspects.
  • Aspect 1 of the present invention is
  • Aspect 2 of the present invention provides
  • Aspect 3 of the present invention provides
  • Aspect 4 of the present invention provides the steel sheet according to any one of Aspects 1 to 3, wherein a component composition satisfies:
  • Aspect 6 of the present invention is the method for manufacturing a steel sheet according to Aspect 5, wherein an attainment temperature in the first reduction treatment and the second reduction treatment is 800 to 920°C.

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)
EP24779731.9A 2023-03-30 2024-03-19 Tôle d'acier et procédé de fabrication de tôle d'acier Pending EP4667607A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2023056165 2023-03-30
JP2024022770A JP2024144148A (ja) 2023-03-30 2024-02-19 鋼板および鋼板の製造方法
PCT/JP2024/010716 WO2024203606A1 (fr) 2023-03-30 2024-03-19 Tôle d'acier et procédé de fabrication de tôle d'acier

Publications (1)

Publication Number Publication Date
EP4667607A1 true EP4667607A1 (fr) 2025-12-24

Family

ID=92904737

Family Applications (1)

Application Number Title Priority Date Filing Date
EP24779731.9A Pending EP4667607A1 (fr) 2023-03-30 2024-03-19 Tôle d'acier et procédé de fabrication de tôle d'acier

Country Status (5)

Country Link
EP (1) EP4667607A1 (fr)
KR (1) KR20250159018A (fr)
CN (1) CN120813719A (fr)
MX (1) MX2025011220A (fr)
WO (1) WO2024203606A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2026004485A1 (fr) * 2024-06-28 2026-01-02 株式会社神戸製鋼所 Tôle d'acier et tôle d'acier plaquée

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017166057A (ja) 2016-03-11 2017-09-21 Ｊｆｅスチール株式会社 高強度溶融亜鉛めっき鋼板の製造方法
JP2023056165A (ja) 2021-10-07 2023-04-19 俊 岸岡 プランター
JP2024022770A (ja) 2022-08-08 2024-02-21 国立大学法人 筑波大学 慢性腎臓病の予防、改善又は治療用組成物

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3769914B2 (ja) * 1998-01-06 2006-04-26 Ｊｆｅスチール株式会社 耐時効性と焼き付け硬化性に優れた缶用鋼板
WO2014037627A1 (fr) * 2012-09-06 2014-03-13 Arcelormittal Investigación Y Desarrollo Sl Procede de fabrication de pieces d'acier revêtues et durcies a la presse, et tôles prerevêtues permettant la fabrication de ces pieces
JP2017075394A (ja) * 2015-10-16 2017-04-20 株式会社神戸製鋼所 高強度溶融亜鉛めっき鋼板及び高強度溶融亜鉛めっき鋼板の製造方法
KR101899680B1 (ko) * 2016-12-21 2018-09-17 주식회사 포스코 표면품질과 도금밀착성이 우수한 고강도 용융아연 도금강판 및 그 제조방법
WO2023007833A1 (fr) * 2021-07-28 2023-02-02 Ｊｆｅスチール株式会社 Tôle d'acier galvanisé et élément et son procédé de fabrication
CN117836195A (zh) * 2021-08-27 2024-04-05 日本制铁株式会社 汽车用外板部件、坯料片、坯料片的制造方法和坯料片的制造设备

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017166057A (ja) 2016-03-11 2017-09-21 Ｊｆｅスチール株式会社 高強度溶融亜鉛めっき鋼板の製造方法
JP2023056165A (ja) 2021-10-07 2023-04-19 俊 岸岡 プランター
JP2024022770A (ja) 2022-08-08 2024-02-21 国立大学法人 筑波大学 慢性腎臓病の予防、改善又は治療用組成物

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO2024203606A1

Also Published As

Publication number Publication date
CN120813719A (zh) 2025-10-17
KR20250159018A (ko) 2025-11-07
WO2024203606A1 (fr) 2024-10-03
MX2025011220A (es) 2025-10-01

Similar Documents

Publication Publication Date Title
US10711336B2 (en) Alloyed hot-dip galvanized steel sheet and method of manufacturing the same
KR101431317B1 (ko) 고강도 용융 아연 도금 강판 및 그 제조 방법
EP2381004B1 (fr) Procédé de fabrication d'une plaque en acier galvanisée à chaud
TWI488978B (zh) Molten galvanized steel sheet and method of manufacturing the same
EP1978113B1 (fr) Toles en acier recuites apres galvanisation de haute resistance excellentes en termes de resistance au farinage et leur procede de production
JP2010126758A (ja) 高強度溶融亜鉛めっき鋼板およびその製造方法
JP7401857B2 (ja) 溶融亜鉛系めっき鋼板の製造方法
WO2023182524A1 (fr) Procédé pour la production de tôle d'acier galvanisée par immersion à chaud à haute résistance
EP3396005B1 (fr) Tôle d'acier contenant du manganèse, recuite après galvanisation par immersion à chaud et son procédé de fabrication
EP4667607A1 (fr) Tôle d'acier et procédé de fabrication de tôle d'acier
JP2010255109A (ja) 高強度溶融亜鉛めっき鋼板およびその製造方法
EP4296385A1 (fr) Procédé de fabrication de tôle en acier
US20250051895A1 (en) Steel sheet and plated steel sheet
EP4667606A1 (fr) Tôle d'acier plaquée et son procédé de fabrication
JP2024144148A (ja) 鋼板および鋼板の製造方法
JP7696817B2 (ja) 鋼板の製造方法
EP4299771A1 (fr) Tôle d'acier pour galvanisation par immersion à chaud, tôle d'acier galvanisée par immersion à chaud et tôle d'acier recuite par galvanisation par immersion à chaud alliée
EP4632086A1 (fr) Corps moulé par estampage à chaud
EP4632084A1 (fr) Feuille d'acier plaquée
EP4671400A1 (fr) Feuille d'acier plaquée et son procédé de fabrication
JP2024144150A (ja) めっき鋼板およびその製造方法
EP4663782A1 (fr) Procédé de fabrication d'une tôle d'acier galvanisée par immersion à chaud
EP4632087A1 (fr) Corps moulé par estampage à chaud
EP4632094A1 (fr) Corps moulé par estampage à chaud

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: 20250918

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

RIN1 Information on inventor provided before grant (corrected)

Inventor name: MAEKAWA, SHUYA

Inventor name: OTOME, RYOSUKE

Inventor name: IRIE, HIROSHI

Inventor name: HIRAI, SHOICHI

Inventor name: KIGUCHI, KENTARO

RIN1 Information on inventor provided before grant (corrected)

Inventor name: MAEKAWA, SHUYA

Inventor name: OTOMO, RYOSUKE

Inventor name: IRIE, HIROSHI

Inventor name: HIRAI, SHOICHI

Inventor name: KIGUCHI, KENTARO