EP4317504A1 - Warmgewalztes stahlblech und verfahren zur herstellung davon - Google Patents

Warmgewalztes stahlblech und verfahren zur herstellung davon Download PDF

Info

Publication number
EP4317504A1
EP4317504A1 EP22780434.1A EP22780434A EP4317504A1 EP 4317504 A1 EP4317504 A1 EP 4317504A1 EP 22780434 A EP22780434 A EP 22780434A EP 4317504 A1 EP4317504 A1 EP 4317504A1
Authority
EP
European Patent Office
Prior art keywords
less
rolling
hot
steel sheet
rolled steel
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
EP22780434.1A
Other languages
English (en)
French (fr)
Inventor
Hiroshi Hasegawa
Hideyuki Kimura
Yukio TATARA
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.)
JFE Steel Corp
Original Assignee
JFE Steel Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by JFE Steel Corp filed Critical JFE Steel Corp
Publication of EP4317504A1 publication Critical patent/EP4317504A1/de
Pending legal-status Critical Current

Links

Classifications

    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
    • 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
    • C21D1/02—Hardening articles or materials formed by forging or rolling, with no further heating beyond that required for the formation
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/001—Heat treatment of ferrous alloys containing Ni
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/002—Heat treatment of ferrous alloys containing Cr
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/008—Heat treatment of ferrous alloys containing Si
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—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
    • C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
    • 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
    • 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
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
    • B21B2001/225—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length by 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
    • C21D2201/00—Treatment for obtaining particular effects
    • C21D2201/05—Grain orientation
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/009—Pearlite

Definitions

  • the present invention relates to a hot-rolled steel sheet and a method for manufacturing the same, and in particular, to a hot-rolled steel sheet suitable as a material for automotive parts and a method for manufacturing the same.
  • Patent Literature 1 discloses a technique related to a hot-rolled steel sheet having excellent fatigue properties and flangeability obtained by adjusting the amounts of C, Si, Mn, P, S, and Al added to appropriate ranges, forming a microstructure composed of fine polygonal ferrite and bainite, and controlling the length and grain boundary coverage of cementite.
  • Patent Literature 2 discloses a technique related to a hot-rolled steel sheet having a further improved strength-elongation balance, endurance ratio, and stretch flanging properties obtained by adjusting the amounts of C, Si, Mn, Al, and Nb added to appropriate ranges and forming a microstructure that is composed of retained austenite and polygonal ferrite and that has fine grains.
  • Patent Literature 3 discloses a technique related to a hot-rolled steel sheet having excellent stretch flangeability and ductility obtained by controlling C, Si, Mn, P, S, Al, N, Mg, Nb, and Ti to appropriate ranges, using ferrite as a main phase, and controlling oxides such as MgO, Al 2 O 3 , Ti 2 O 3 , SiO 2 , and MnO.
  • Patent Literature 1 the hole expansion ratio remains less than 100%, and there is no finding or suggestion to further improve the hole expansion ratio. Moreover, the amount of O in steel and the crystallographic orientation are not studied. In Patent Literature 2, 5% to 20% of retained austenite is introduced in order to improve toughness and fatigue properties. However, retained austenite becomes martensite at the time of punching to reduce stretch flangeability, and thus flangeability sufficient to withstand severe stretch flanging is not obtained. Moreover, there is no disclosure of a technique related to the amount of O in steel or the crystallographic orientation. Although the oxides are controlled in Patent Literature 3, there is no knowledge suggesting that the flangeability is improved by controlling the amount of oxygen itself, and the crystallographic orientation is not taken into consideration.
  • the present invention has been made to solve the above problems, and it is an object of the present invention to provide a hot-rolled steel sheet having excellent stretch flangeability.
  • the inventors have conducted intensive studies focusing on O in steel and the crystallographic orientation and have found that stretch flangeability can be markedly improved by randomizing the crystallographic orientation while controlling the amount of O in steel to a certain level or less, leading to the completion of the present invention.
  • excellent stretch flangeability indicates that the hole expansion ratio is 100% or more.
  • the present invention has the following configurations.
  • a hot-rolled steel sheet having excellent stretch flangeability is provided.
  • a hot-rolled steel sheet that is suitable as a material for automotive parts and that has excellent stretch flangeability.
  • the use of the hot-rolled steel sheet of the present invention enables the production of, for example, automotive parts with high yields.
  • a hot-rolled steel sheet and a method for manufacturing the hot-rolled steel sheet according to the present invention will be described in detail below.
  • the present invention is not limited to the following embodiments.
  • the hot-rolled steel sheet of the present invention may be a non-pickled hot-rolled steel sheet, which is as hot rolled, or a pickled hot-rolled steel sheet, which has been further pickled after hot rolling.
  • the hot-rolled steel sheet of the present invention preferably has a thickness of 0.6 mm or more.
  • the hot-rolled steel sheet of the present invention preferably has a thickness of 10.0 mm or less.
  • the thickness is more preferably 1.0 mm or more.
  • the hot-rolled steel sheet of the present invention is used as a material for automotive parts, the thickness is more preferably 6.0 mm or less.
  • the hot-rolled steel sheet of the present invention preferably has a width of 500 mm or more, more preferably 700 mm or more.
  • the hot-rolled steel sheet of the present invention preferably has a width of 1,800 mm or less, more preferably 1,400 mm or less.
  • the hot-rolled steel sheet of the present invention has a specific chemical composition and a specific steel microstructure.
  • the chemical composition and the steel microstructure will be described in this order.
  • the hot-rolled steel sheet of the present invention has a chemical composition containing, by mass%, C: 0.10% or less, Si: 2.0% or less, Mn: 2.0% or less, P: 0.100% or less, S: 0.02% or less, Al: 1.5% or less, and O: 0.0025% or less, the balance being Fe and incidental impurities.
  • C is preferably minimized as much as possible in order to obtain ferrite.
  • a C content of up to 0.10% is allowable.
  • a C content of more than 0.10% results in increases of, for example, pearlite and bainite, thereby failing to obtain the microstructure of the present invention.
  • the C content is 0.10% or less.
  • the C content is preferably 0.08% or less, more preferably 0.05% or less.
  • a C content of 0.0001% or more is preferred because a C content of less than 0.0001% leads to a decrease in production efficiency.
  • Si is an element effective in increasing the strength of steel through solid solution strengthening to increase the tensile strength (TS).
  • TS tensile strength
  • Si is an element also effective in promoting the formation of ferrite.
  • Si can be appropriately added in consideration of the strength and microstructure.
  • an excessive addition of Si leads to embrittlement of the steel and the accumulation of the crystallographic orientation, thereby deteriorating the stretch flangeability.
  • the amount of Si added needs to be 2.0% or less.
  • the Si content is 2.0% or less (including 0%).
  • the Si content is preferably 1.0% or less, more preferably 0.6% or less.
  • a Si content of 0.001% or more is preferred because a Si content of less than 0.001% leads to a decrease in production efficiency.
  • Mn is preferably minimized as much as possible in order to obtain ferrite.
  • a Mn content of up to 2.0% is allowable in the present invention.
  • a Mn content of more than 2.0% does not sufficiently result in the effect. Martensite, bainite, and so forth may be formed, failing to obtain the microstructure of the present invention.
  • a large amount of MnS is formed, failing to obtain the desired stretch flangeability.
  • the Mn content is 2.0% or less.
  • the Mn content is preferably 1.6% or less, more preferably 1.0% or less.
  • a Mn content of 0.01% or more is preferred because a Mn content of less than 0.01% may lead to a decrease in production efficiency.
  • P causes embrittlement of the steel, deteriorating the stretch flangeability.
  • the amount thereof is desirably minimized as much as possible.
  • a P content of up to 0.100% is allowable in the present invention. Accordingly, the P content is 0.100% or less.
  • the P content is preferably 0.050% or less. Although the lower limit is not particularly specified, a P content of 0.001% or more is preferred because a P content of less than 0.001% leads to a decrease in production efficiency.
  • S causes embrittlement of the steel, deteriorating the stretch flangeability.
  • the amount thereof is desirably minimized as much as possible.
  • a S content of up to 0.02% is allowable in the present invention. Accordingly, the S content is 0.02% or less.
  • the S content is preferably 0.010% or less, more preferably 0.0080% or less.
  • the lower limit is not particularly specified, a S content of 0.0002% or more is preferred because a S content of less than 0.0002% leads to a decrease in production efficiency.
  • Al a large amount of Al contained results in the development of the texture, failing to obtain the steel microstructure of the present invention.
  • An Al content of up to 1.5% is allowable in the present invention. Accordingly, the Al content is 1.5% or less.
  • the Al content is preferably 0.50% or less. Although the lower limit is not particularly specified, an Al content of 0.001% or more is preferred because an Al content of less than 0.001% may lead to a decrease in production efficiency.
  • O is an important element of the present invention and is desirably minimized as much as possible because O leads to embrittlement of the steel, promotion of the accumulation of the crystallographic orientation, and the increase of inclusions to deteriorate stretch flangeability.
  • the O content needs to be 0.0025% or less. Accordingly, the O content is 0.0025% or less.
  • the O content is preferably 0.0020% or less.
  • an O content of 0.0001% or more is preferred because an O content of less than 0.0001% leads to a decrease in production efficiency.
  • the balance is Fe and incidental impurities.
  • incidental impurities include N, Na, Mg, Zr, Hf, Ta, and W.
  • the total amount thereof is 0.020% or less.
  • the total amount is more preferably 0.010% or less.
  • the above components are the basic chemical composition of the hot-rolled steel sheet of the present invention.
  • the following elements may be further contained as appropriate.
  • Cr, Ti, Nb, Mo, and V are elements effective in forming carbides to increase the strength of steel.
  • the amounts of individual elements contained are preferably equal to or higher than their respective lower limits described above.
  • the amounts of individual elements contained are more than the respective upper limits described above, the increases of bainite and martensite and the development of the texture may be caused, failing to obtain the microstructure of the present invention.
  • the amounts of elements contained are preferably Cr: 0.005% to 2.0%, Ti: 0.005% to 0.20%, Nb: 0.005% to 0.20%, Mo: 0.01% to 2.0%, and V: 0.01% to 1.0%.
  • the Cr content is more preferably 0.05% or more.
  • the Cr content is more preferably 1.0% or less.
  • the Ti content is more preferably 0.01% or more.
  • the Ti content is more preferably 0.15% or less.
  • the Nb content is more preferably 0.01% or more.
  • the Nb content is more preferably 0.10% or less.
  • the Mo content is more preferably 0.05% or more.
  • the Mo content is more preferably 1.0% or less.
  • the V content is more preferably 0.05% or more.
  • the V content is more preferably 0.5% or less.
  • Cu and Ni are elements effective in increasing the strength of steel through solid solution strengthening.
  • the amounts of individual elements contained are preferably equal to or higher than their respective lower limits described above.
  • the amounts of individual elements contained are preferably Cu: 0.01 to 4.0% and Ni: 0.005 to 2.0%.
  • the Cu content is more preferably 0.05% or more.
  • the Cu content is more preferably 1.0% or less.
  • the Ni content is more preferably 0.05% or more.
  • the Ni content is more preferably 1.0% or less.
  • the B is an element effective in strengthening grain boundaries to increase the strength of steel.
  • the B content is preferably 0.0001% or more.
  • a B content of more than 0.01% may result in the increase of a B-containing compound to deteriorate the stretch flangeability.
  • the B content is preferably 0.0001% to 0.01%.
  • the B content is more preferably 0.0005% or more.
  • the B content is more preferably 0.0040% or less.
  • Ca and REM are elements effective in improving stretch flangeability due to their contribution to the shape control of inclusions.
  • the amount of each element contained is preferably 0.0001% or more.
  • each of the Ca content and the REM content is more than the corresponding upper limit described above, the amount of inclusions may increase to deteriorate the stretch flangeability.
  • their individual contents are preferably Ca: 0.0001% to 0.0050% and REM: 0.0001% to 0.0050%.
  • the Ca content is more preferably 0.0005% or more.
  • the Ca content is more preferably 0.0030% or less.
  • the REM content is more preferably 0.0005% or more.
  • the REM content is more preferably 0.0030% or less.
  • REM is a general term for Sc, Y, and 15 elements ranging from lanthanum (La) with atomic number 57 to lutetium (Lu) with atomic number 71, and the REM content used here refers to the total amount of these elements contained.
  • Sb and Sn are elements effective in suppressing denitrification, deboronization, and so forth to inhibit a decrease in the strength of steel.
  • the amount of each element contained is preferably 0.0010% or more.
  • each of the Sb content and the Sn content is more than the corresponding upper limit described above, the steel may embrittle to deteriorate stretch flangeability.
  • Sb and Sn are contained, their individual contents are preferably Sb: 0.0010% to 0.10% and Sn: 0.0010 to 0.10%.
  • the Sb content is more preferably 0.005% or more.
  • the Sb content is more preferably 0.015% or less.
  • the Sn content is more preferably 0.005% or more.
  • the Sn content is more preferably 0.015% or less.
  • the steel microstructure of the hot-rolled steel sheet of the present invention will be described below.
  • the steel microstructure of the hot-rolled steel sheet according to the present invention is characterized in that the main phase is ferrite and the maximum orientation density of grains is 2.1 or less.
  • the main phase is ferrite.
  • the main phase refers to a phase having an area fraction of more than 50%.
  • the area fraction of ferrite is preferably 90% or more, more preferably 95% or more.
  • the balance other than ferrite is one or more of martensite, bainite, pearlite, and retained austenite.
  • the area fraction of the balance is preferably 10% or less, more preferably 5% or less.
  • the area fraction of each phase (microstructure) can be determined by a method described in Examples.
  • the maximum orientation density of the grains is 2.1 or less.
  • the maximum orientation density of the grains is preferably 2.0 or less, more preferably 1.9 or less.
  • the maximum orientation density of the grains is preferably 1.0 or more.
  • the maximum orientation density of the grains can be determined by a method described in Examples.
  • the stretch flangeability can be further improved by promoting randomization of the crystallographic orientation.
  • the effect can be provided by setting the maximum orientation density of grains to 1.5 or less in a plane inclined in the thickness direction at an angle of 45° with respect to a surface of the sheet from a direction perpendicular to the rolling direction.
  • the maximum orientation density of the grains is preferably 1.5 or less in the plane inclined in the thickness direction at an angle of 45° with respect to the surface of the sheet from the direction perpendicular to the rolling direction.
  • the maximum orientation density of the grains is more preferably 1.4 or less, still more preferably 1.3 or less, in the plane inclined in the thickness direction at an angle of 45° with respect to the surface of the sheet from the direction perpendicular to the rolling direction.
  • the maximum orientation density of the grains is preferably 1.0 or more in the plane inclined in the thickness direction at an angle of 45° with respect to the surface of the sheet from the direction perpendicular to the rolling direction.
  • the maximum orientation density of the grains in the plane inclined in the thickness direction at an angle of 45° with respect to the surface of the sheet from the direction perpendicular to the rolling direction can be determined by a method described in Examples.
  • the hot-rolled steel sheet of the present invention is manufactured by heating a slab to 1,100°C or higher, the slab having the chemical composition described above, performing rolling in 6 passes or more at a rolling reduction of 15% or more per pass in a temperature range of 1,000°C or higher, then performing rolling under conditions in which the rolling is performed in 3 passes or more in a temperature range of lower than 1,000°C at a rolling reduction of 15% or more per pass, a rolling time is 2.0 seconds or less in a temperature range of lower than 1,000°C, and a final pass rolling temperature is 850°C to 940°C, and subsequently performing cooling to 700°C at an average cooling rate of 50 °C/s or more, and performing coiling at 580°C to 700°C.
  • the temperature described above is the surface temperature of the central portion of the width of the steel sheet
  • the average cooling rate described above is the average cooling rate at the surface of the central portion of the width of the steel sheet.
  • the average cooling rate is [(cooling start temperature - finish cooling temperature)/cooling time from the cooling start temperature to the finish cooling temperature] unless otherwise specified.
  • a steel having the above-described chemical composition is obtained by a known steelmaking method using, for example, a converter, an electric arc furnace, or a vacuum melting furnace, and is cast by a known method, such as a continuous casting method or an ingot making-slabbing method to form a cast slab (slab).
  • the slab heating temperature is 1,100°C or higher.
  • the slab heating temperature is preferably 1,150°C or higher.
  • the slab heating temperature is preferably 1,350°C or lower because of an increase in electric power cost or the like at higher than 1,350°C.
  • the number of rolling passes (the number of rolling times) in a temperature range of 1,000°C or higher in the hot rolling is less than 6 passes (6 times), recrystallization is insufficient; thus, the randomization of the crystallographic orientation is inhibited, failing to obtain the maximum orientation density of the grains of the present invention.
  • the number of rolling passes in the temperature range of 1,000°C or higher is 6 passes or more.
  • the number of rolling passes is preferably 8 passes or more, more preferably 10 passes or more.
  • the upper limit is not particularly specified, the number of rolling passes is preferably 20 passes or less because an increase in the number of rolling passes may lead to a decrease in production efficiency or the like.
  • the rolling in the temperature range of 1,000°C or higher includes rolling in any process as long as the rolling is performed in the temperature range of 1,000°C or higher regardless of the process of rough rolling or finish rolling. The same applies to rolling in a temperature range of lower than 1,000°C described below.
  • the rolling reduction per pass (one time) of the hot rolling in the temperature range of 1,000°C or higher is less than 15%, recrystallization is insufficient; thus, the randomization of the crystallographic orientation is inhibited, failing to obtain the maximum orientation density of the grains of the present invention. Accordingly, the rolling reduction per pass of rolling in the temperature range of 1,000°C or higher is 15% or more.
  • the rolling reduction is preferably 18% or more, more preferably 20% or more.
  • the rolling reduction is preferably 80% or less because a rolling reduction of more than 80% may lead to a problem such as an increase in equipment load.
  • the number of rolling passes (the number of times of rolling) in the temperature region of lower than 1,000°C in the hot rolling is less than 3 passes (3 times), insufficient strain accumulation decreases ferrite with random orientations during subsequent ferrite transformation, failing to obtain the maximum orientation density of the grains of the present invention.
  • the number of rolling passes in the temperature range of lower than 1,000°C is 3 passes or more.
  • the number of rolling passes is preferably 4 passes or more.
  • the upper limit is not particularly specified, the number of rolling passes is preferably 8 passes or less because an increase in the number of rolling passes leads to a decrease in rolling temperature in the final rolling pass (final finish rolling pass).
  • the rolling reduction per pass (one time) of the hot rolling in the temperature range of lower than 1,000°C is less than 15%, insufficient strain accumulation decreases ferrite with random orientations during subsequent ferrite transformation, failing to obtain the maximum orientation density of the grains of the present invention. Accordingly, the rolling reduction per pass in the temperature range of lower than 1,000°C is 15% or more.
  • the rolling reduction is preferably 170 or more, more preferably 20% or more.
  • the rolling reduction is preferably 50% or less because an increase in rolling reduction may lead to a decrease in shape stability or the like.
  • the rolling time in the temperature range of lower than 1,000°C is more than 2.0 seconds, insufficient strain accumulation decreases ferrite with random orientations during subsequent ferrite transformation, failing to obtain the maximum orientation density of the grains of the present invention. Accordingly, the rolling time in the temperature range of lower than 1,000°C is 2.0 seconds or less.
  • the rolling time in the temperature range of lower than 1,000°C indicates the time from when the same portion of the material to be rolled reaches a temperature of lower than 1,000°C and comes into contact with the rolling rolls of the first rolling pass to when the portion leaves (passes through) the rolling rolls of the final rolling pass.
  • the rolling time is preferably 1.7 seconds or less, more preferably 1.4 seconds or less.
  • the rolling time is preferably 0.2 seconds or more because rolling at an excessively high speed causes a decrease in operational stability.
  • the final pass rolling temperature (finishing delivery temperature) is lower than 850°C, excessive strain accumulation decreases ferrite with random orientations during subsequent ferrite transformation, failing to obtain the maximum orientation density of the grains of the present invention.
  • the rolling temperature is higher than 940°C, insufficient strain accumulation decreases ferrite with random orientations during subsequent ferrite transformation, failing to obtain the maximum orientation density of grains of the present invention.
  • the final pass rolling temperature is 850°C to 940°C.
  • the rolling temperature is preferably 860°C or higher, more preferably 870°C or higher.
  • the rolling temperature is preferably 920°C or lower, more preferably 910°C or lower.
  • the average cooling rate from the final pass rolling temperature (finishing delivery temperature) to 700°C is less than 50 °C/s, the rolling strain is partially released to lead to insufficient strain accumulation; thus, ferrite with random orientations decreases during subsequent ferrite transformation, failing to obtain the maximum orientation density of grains of the present invention. Accordingly, the average cooling rate from the final pass rolling temperature to 700°C is 50 °C/s or more.
  • the average cooling rate is preferably 80 °C/s or more.
  • the average cooling rate is preferably 1,000 °C/s or less from the viewpoint of the shape stability of the steel sheet and so forth.
  • a coiling temperature of lower than 580°C results in the increases of bainite and martensite, failing to obtain the steel microstructure of the present invention.
  • a coiling temperature of higher than 700°C results in a low degree of undercooling of ferrite transformation; thus, ferrite with random orientations decreases during the ferrite transformation, failing to obtain the maximum orientation density of the grains of the present invention.
  • the coiling temperature is 580°C to 700°C.
  • the coiling temperature is preferably 590°C or higher.
  • the coiling temperature is preferably 680°C or lower. After the coiling, the sheet is cooled to room temperature, for example.
  • the tensile strength (TS) of the hot-rolled steel sheet of the present invention is preferably, but not particularly limited to, 200 MPa or more, more preferably 270 MPa or more.
  • the tensile strength (TS) of the hot-rolled steel sheet of the present invention is preferably, but not particularly limited to, 780 MPa or less, more preferably 650 MPa or less.
  • the hot-rolled steel sheet of the present invention has excellent stretch flangeability with a hole expansion ratio of 100% or more.
  • the hole expansion ratio is preferably 110% or more, more preferably 120% or more.
  • TS and the hole expansion ratio are each determined by a method described in Examples.
  • Steels having respective chemical compositions given in Table 1 were obtained by steelmaking in a vacuum melting furnace and formed into slabs.
  • the slabs were heated and hot-rolled under the conditions given in Table 2.
  • the resulting hot-rolled steel sheets were used to make evaluation on microstructure observation, tensile properties, and a hole expansion test according to the following test methods.
  • the area fraction of ferrite was determined as follows: A sample was cut out from the resulting hot-rolled steel sheet. A cross section in the thickness direction and parallel to the rolling direction was polished and then etched in 3% nital. A position 1/4 of the thickness was photographed in three visual fields at a magnification of ⁇ 1,500 with a scanning electron microscope (SEM). The area fraction of each microstructure was determined from the image data of the obtained secondary electron image using Image-Pro available from Media Cybernetics, Inc., and the average area fraction of the three visual fields was defined as the area fraction of each microstructure. In the image data, ferrite is black or dark gray and has smooth grain boundaries. Carbides appear white dots or lines. A lamellar microstructure composed of ferrite and a carbide is distinguished as pearlite. Microstructures other than the above were distinguished as others.
  • the crystal orientation was determined by electron backscatter diffraction (EBSD) in a 500 pm ⁇ 500 pm region centered at a position 1/4 of the thickness of a cross section in the thickness direction and parallel to the rolling direction.
  • EBSD electron backscatter diffraction
  • the range of each of ⁇ 1, ⁇ 2, and ⁇ was set to 0 to 90, the resolution of each was set to 5, and the orientation distribution function (ODF) was calculated to determine the maximum orientation density of grains in the field of view. This was performed for similar five points, and the average thereof was used as the maximum orientation density of the grains.
  • the above-described crystallographic orientation data was subjected to coordinate transformation in such a manner that the normal direction (ND) plane was a plane inclined in the thickness direction at an angle of 45° with respect to a surface of the sheet from a direction perpendicular to the rolling direction.
  • the range of each of ⁇ 1, ⁇ 2, and ⁇ was set to 0 to 90, the resolution of each was set to 5, and the orientation distribution function (ODF) was calculated to determine the maximum orientation density of grains in the field of view. This was performed for similar five points, and the average thereof was used as the maximum orientation density of the grains in the plane inclined in the thickness direction at an angle of 45° with respect to the surface of the sheet from the direction perpendicular to the rolling direction.
  • the EBSD measurement was performed at an accelerating voltage of 30 kV and a step size of 0.5 pm.
  • JIS Z 2201 A JIS No. 5 test piece for a tensile test (JIS Z 2201) was sampled from the resulting hot-rolled steel sheet in a direction parallel to the rolling direction. The tensile test was performed in accordance with JIS Z 2241 at a strain rate of 10 -3 /s to determine tensile strength (TS).
  • Test pieces each having a width of 100 mm and a length of 100 mm were collected from the resulting hot-rolled steel sheets.
  • a hole expansion test was performed five times in accordance with JFST1001 (The Japan Iron and Steel Federation Standard). The average hole expansion ratio ⁇
  • the hot-rolled steel sheets obtained in all inventive examples have excellent stretch flangeability.
  • desired stretch flangeability is not obtained.
  • a hot-rolled steel sheet having excellent stretch flangeability can be stably obtained.
  • the steel sheet of the present invention is used for automotive parts, the steel sheet can greatly contribute to the improvements of the crash safety and fuel economy of automobiles.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Heat Treatment Of Steel (AREA)
EP22780434.1A 2021-03-30 2022-03-23 Warmgewalztes stahlblech und verfahren zur herstellung davon Pending EP4317504A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2021056688 2021-03-30
PCT/JP2022/013740 WO2022210220A1 (ja) 2021-03-30 2022-03-23 熱延鋼板およびその製造方法

Publications (1)

Publication Number Publication Date
EP4317504A1 true EP4317504A1 (de) 2024-02-07

Family

ID=83459175

Family Applications (1)

Application Number Title Priority Date Filing Date
EP22780434.1A Pending EP4317504A1 (de) 2021-03-30 2022-03-23 Warmgewalztes stahlblech und verfahren zur herstellung davon

Country Status (7)

Country Link
US (1) US20240167114A1 (de)
EP (1) EP4317504A1 (de)
JP (1) JP7435796B2 (de)
KR (1) KR20230148840A (de)
CN (1) CN117062931A (de)
MX (1) MX2023011386A (de)
WO (1) WO2022210220A1 (de)

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09170048A (ja) 1995-12-15 1997-06-30 Kobe Steel Ltd 疲労特性と穴拡げ性に優れた加工用高強度熱延鋼板
JPH111747A (ja) 1997-06-06 1999-01-06 Kawasaki Steel Corp 超微細粒を有する延性、靱性、耐疲労特性および強度−伸びバランスに優れた高張力熱延鋼板およびその製造方法
JP3545696B2 (ja) 2000-03-30 2004-07-21 新日本製鐵株式会社 穴拡げ性と延性に優れた高強度熱延鋼板及びその製造方法
JP4161935B2 (ja) * 2004-04-16 2008-10-08 住友金属工業株式会社 熱延鋼板およびその製造方法
US10428409B2 (en) * 2011-03-18 2019-10-01 Nippon Steel Corporation Hot-rolled steel sheet with excellent press formability and production method thereof
JP6354271B2 (ja) * 2014-04-08 2018-07-11 新日鐵住金株式会社 低温靭性と均一伸びと穴拡げ性に優れた引張強度７８０ＭＰａ以上の高強度熱延鋼板及びその製造方法
CN107746939B (zh) * 2017-10-11 2019-09-03 首钢集团有限公司 一种590MPa级高强度低合金热轧酸洗带钢及其生产方法

Also Published As

Publication number Publication date
WO2022210220A1 (ja) 2022-10-06
MX2023011386A (es) 2023-10-09
US20240167114A1 (en) 2024-05-23
JP7435796B2 (ja) 2024-02-21
KR20230148840A (ko) 2023-10-25
JPWO2022210220A1 (de) 2022-10-06
CN117062931A (zh) 2023-11-14

Similar Documents

Publication Publication Date Title
EP3009527B1 (de) Hochfestes kaltgewalztes stahlblech und verfahren zur herstellung davon
US9255306B2 (en) Steel wire rod and method of producing same
EP3128027B1 (de) Hochfestes kaltgewalztes stahlblech mit hohem streckgrenzenverhältnis und herstellungsverfahren dafür
EP3395974B1 (de) Hochfeste stahlband und herstellungsverfahren dafür
EP2937433B1 (de) Hochfestes kaltgewalztes stahlblech mit hohem ertrag und verfahren zur herstellung davon
EP3263728B1 (de) Hochfeste kaltgewalzte stahlplatte und verfahren zu deren herstellung
EP3106528B1 (de) Hochfestes feuerverzinktes stahlblech und verfahren zur herstellung eines hochfesten legierten feuerverzinkten stahlblechs
EP2671964B1 (de) Hochfestes kaltgewalztes stahlblech mit hervorragender bearbeitbarkeit und hohem streckgrenzenverhältnis sowie herstellungsverfahren dafür
WO2011142356A1 (ja) 高強度鋼板及びその製造方法
EP2765211B1 (de) Heissgewalztes stahlblech mit hoher bruchfestigkeit und verfahren zu seiner herstellung
EP3757242B1 (de) Hochfeste stahlplatte und herstellungsverfahren dafür
WO2016148037A1 (ja) 冷間加工性と浸炭熱処理後の靱性に優れる浸炭用鋼板
EP3889283B1 (de) Hochfestes stahlblech und verfahren zur herstellung desselben
CN113166839B (zh) 热浸镀锌钢板及其制造方法
WO2021193310A1 (ja) 高強度熱延鋼板及びその製造方法
EP3613868A1 (de) Hochfestes feuerverzinktes stahlblech und produktionsverfahren dafür
KR101979477B1 (ko) 퀀칭성이 우수한 면내 이방성이 작은 고탄소 열연 강판 및 그 제조 방법
EP4029956A1 (de) Hochfestes stahlblech und herstellungsverfahren dafür
EP4321646A1 (de) Hochfestes warmgewalztes stahlblech und verfahren zur herstellung eines hochfesten warmgewalzten stahlblechs
JP7078186B1 (ja) 高強度冷延鋼板，高強度めっき鋼板，高強度冷延鋼板の製造方法，及び高強度めっき鋼板の製造方法
WO2021005971A1 (ja) 熱間圧延鋼板
EP4317504A1 (de) Warmgewalztes stahlblech und verfahren zur herstellung davon
JP7070812B1 (ja) 高強度冷延鋼板，高強度めっき鋼板，高強度冷延鋼板の製造方法，高強度めっき鋼板の製造方法，及び自動車部品
JP7201136B1 (ja) 鋼矢板及びその製造方法
EP4324952A1 (de) Kaltgewalztes stahlblech, stahlbauteile, verfahren zur herstellung eines kaltgewalzten stahlblechs und verfahren zur herstellung von stahlbauteilen

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: 20230912

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 MK MT NL NO PL PT RO RS SE SI SK SM TR