WO2023068369A1 - Tôle d'acier - Google Patents

Tôle d'acier Download PDF

Info

Publication number
WO2023068369A1
WO2023068369A1 PCT/JP2022/039380 JP2022039380W WO2023068369A1 WO 2023068369 A1 WO2023068369 A1 WO 2023068369A1 JP 2022039380 W JP2022039380 W JP 2022039380W WO 2023068369 A1 WO2023068369 A1 WO 2023068369A1
Authority
WO
WIPO (PCT)
Prior art keywords
less
content
steel sheet
hydrogen embrittlement
martensite
Prior art date
Application number
PCT/JP2022/039380
Other languages
English (en)
Japanese (ja)
Inventor
光陽 大賀
健悟 竹田
克哉 中野
Original Assignee
日本製鉄株式会社
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 日本製鉄株式会社 filed Critical 日本製鉄株式会社
Priority to CN202280070217.2A priority Critical patent/CN118140000A/zh
Priority to KR1020247012403A priority patent/KR20240069758A/ko
Publication of WO2023068369A1 publication Critical patent/WO2023068369A1/fr

Links

Images

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
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • 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
    • 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
    • C22C38/008—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
    • C22C38/02—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
    • C22C38/06—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
    • C22C38/18—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
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—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
    • C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/001—Austenite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/002—Bainite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/008—Martensite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/009—Pearlite

Definitions

  • the present invention relates to steel sheets. This application claims priority based on Japanese Patent Application No. 2021-172424 filed in Japan on October 21, 2021, the contents of which are incorporated herein.
  • High-strength steel sheets with a tensile strength of 1500 MPa or more often have a microstructure mainly composed of martensite or tempered martensite. It segregates at the grain boundary and embrittles the grain boundary (reduces the grain boundary strength), resulting in cracking (hydrogen embrittlement occurs). Since the intrusion of hydrogen occurs even at room temperature, there is no method for completely suppressing the intrusion of hydrogen. So far, many proposals have been made for techniques for improving the hydrogen embrittlement resistance (sometimes referred to as hydrogen embrittlement resistance) of high-strength steel sheets. (For example, see Patent Documents 1 to 6)
  • Patent Document 1 as an ultra-high-strength steel sheet excellent in hydrogen embrittlement resistance and workability, in mass%, C: more than 0.25 to 0.60%, Si: 1.0 to 3.0%, Mn: 1.0 to 3.5%, P: 0.15% or less, S: 0.02% or less, Al: 1.5% or less (excluding 0%), Mo: 1.0% or less ( 0%), Nb: 0.1% or less (not including 0%), the balance being iron and inevitable impurities, and the metal structure after tensile working with a working rate of 3%, Retained austenite structure: 1% or more, bainitic ferrite and martensite: 80% or more in total, ferrite and pearlite: 9% or less in total (including 0%), and the residual Disclosed is an ultra-high-strength steel sheet with excellent hydrogen embrittlement resistance, characterized by satisfying an average axial ratio (major axis/minor axis) of austenite grains: 5 or more and having a tensile strength of 11
  • a high-strength steel sheet having a tensile strength of 1500 MPa or more contains Si + Mn: 1.0% or more in the steel composition, and the main phase structure is a layer of ferrite and carbide.
  • a layered structure having an aspect ratio of 10 or more and a spacing between layers of 50 nm or less accounts for 65% or more of the entire structure, and further, the carbide forming layers with ferrite has an aspect ratio of 10 or more and is rolled.
  • a high-strength steel sheet having excellent bending properties in the rolling direction and delayed fracture resistance is disclosed by making the fraction of carbides having an angle of 25° or less with respect to the direction 75% or more in terms of area ratio. .
  • Patent Document 3 as a thin ultra-high strength cold-rolled steel sheet excellent in bendability and delayed fracture resistance, C: 0.15 to 0.30%, Si: 0.01 to 1.8%, Mn: 1.5 to 3.0%, P: 0.05% or less, S: 0.005% or less, Al: 0.005 to 0.05%, N: 0.005% or less, and the balance is composed of Fe and unavoidable impurities, and has a steel sheet surface soft part that satisfies the relationship "hardness of steel sheet surface soft part/hardness of steel sheet central part ⁇ 0.8", and the ratio of the steel sheet surface soft part to the thickness is 0.10 or more and 0.30 or less, the steel sheet surface soft portion has a tempered martensite volume ratio of 90% or more, the structure of the steel sheet central portion is tempered martensite, and the tensile strength is 1270 MPa or more.
  • An ultra-high-strength cold-rolled steel sheet with excellent bendability characterized by the following is disclosed.
  • Patent Document 4 as a cold-rolled steel sheet having a tensile strength of 1470 MPa or more and excellent bending workability and delayed fracture resistance, C: 0.15 to 0.20%, Si: 1.0 to 2.0% by mass %. 0%, Mn: 1.5 to 2.5%, P: 0.020% or less, S: 0.005% or less, Al: 0.01 to 0.05%, N: 0.005% or less, Ti : 0.1% or less, Nb: 0.1% or less, B: 5 to 30 ppm, the balance being Fe and unavoidable impurities, and the tempered martensite phase is 97% or more by volume, and the retained austenite phase is A cold-rolled steel sheet having a metal structure with a volume fraction of less than 3% is disclosed.
  • Patent Document 5 in an ultra-high-strength steel sheet having a tensile strength of 1470 MPa or more, as an ultra-high-strength steel sheet that can exhibit excellent delayed fracture resistance even at the cut end, C: 0.15 to 0.15 by mass%.
  • the component composition is limited to P: 0.1% or less, S: 0.01% or less, and N: 0.01% or less, and the area ratio to the entire structure is martensite: 90% or more, Retained austenite: A region having a structure of 0.5% or more and a local Mn concentration of 1.1 times or more the Mn content of the entire steel sheet exists in an area ratio of 2% or more, and the tensile strength is An ultra-high-strength steel sheet of 1470 MPa or higher is disclosed.
  • Patent Document 6 as an ultra-high-strength cold-rolled steel sheet having excellent hydrogen embrittlement resistance and a tensile strength of 1300 MPa or more, C: 0.150 to 0.300%, Si: 0.001 to 2.0%, Mn: 2.10 to 4.0%, P: 0.05% or less, S: 0.01% or less, N: 0.01% or less, Al: 0.001% to 1.0%, Ti: 0 .001% to 0.10%, B: 0.0001% to 0.010%, and the value of solid solution B amount solB [mass%] and prior austenite grain size D ⁇ [ ⁇ m] are solB ⁇ D ⁇ 0.
  • polygonal ferrite is 10% or less
  • bainite is 30% or less
  • retained austenite is 6% or less
  • tempered martensite is 60% or more
  • the number density of Fe carbides in the tempered martensite is 1 ⁇ 10 6 /mm 2 or more
  • the average dislocation density of the entire steel is 1.0 ⁇ 10 15 to 2.0 ⁇ 10 16 /m 2
  • the grain size is 7.0 ⁇ m or less.
  • Patent Document 1 only discloses the hydrogen embrittlement resistance when a stress of 1000 MPa is applied, and does not provide a technical solution guideline for the hydrogen embrittlement resistance when a higher stress is applied. nothing is shown.
  • hydrogen embrittlement occurs when hydrogen accumulates at grain boundaries and reduces the bonding strength of grain boundaries. Therefore, if the bonding strength of grain boundaries can be increased, cracking due to hydrogen embrittlement can be suppressed.
  • Patent Documents 1 to 6 do not discuss a method for improving hydrogen embrittlement resistance from such a viewpoint.
  • Patent Documents 1 to 6 may not be able to meet such strict requirements. That is, conventionally, there is room for improvement in hydrogen embrittlement resistance in high-strength steel sheets having a microstructure mainly composed of martensite and tempered martensite.
  • the steel sheet has a pearlite structure as the main phase, the ferrite phase in the remaining structure has a volume ratio of 20% or less with respect to the entire structure, and the lamellar spacing of the pearlite structure is 500 nm or less. It is obtained by subjecting a steel plate having a Vickers hardness of HV200 or more to cold rolling at a rolling reduction of 60% or more (preferably 75% or more). Therefore, it can be easily estimated that the anisotropy is strong and the formability of the member by cold pressing is low. Moreover, in Patent Document 3, in order to improve the delayed fracture characteristics, it is necessary to provide retention for 20 minutes or more at 650° C. or 700° C. in an atmosphere with a dew point of 15° C. or more, and there is also a problem of low productivity.
  • An object of the present invention is to provide a steel sheet excellent in hydrogen embrittlement resistance on the premise of a high-strength steel sheet having a microstructure mainly composed of martensite and tempered martensite.
  • hydrogen embrittlement is considered to be cracks that occur starting from the grain boundaries due to the segregation of hydrogen in the steel at the grain boundaries, which reduces the bonding strength of the grain boundaries. Therefore, the present inventors focused on the bonding strength of grain boundaries and conducted various studies on methods for improving hydrogen embrittlement resistance. As a result, the present inventors have found that by segregating a predetermined alloying element to the grain boundary, the bonding strength of the grain boundary is improved, and the intruding hydrogen is less likely to segregate in the grain boundary. , it is possible to suppress the decrease in the bonding strength of the grain boundary due to hydrogen.
  • a steel sheet according to an aspect of the present invention has, in mass%, C: 0.150 to 0.400%, Si: 0.01 to 2.00%, Mn: 0.80 to 2.00%, P: 0.0001-0.0200%, S: 0.0001-0.0200%, Al: 0.001-1.000%, N: 0.0001-0.0200%, O: 0.0001- 0.0200%, Co: 0-0.500%, Ni: 0-1.000%, Mo: 0-1.000%, Cr: 0-2.000%, Ti: 0-0.500%, B: 0-0.0100%, Nb: 0-0.500%, V: 0-0.500%, Cu: 0-0.500%, W: 0-0.100%, Ta: 0-0 .100%, Mg: 0-0.050%, Ca: 0-0.050%, Y: 0-0.050%, Zr: 0-0.050%, La: 0-0.050%, Ce : 0-0.050%, S
  • the structure has an area ratio of ferrite: 5.0% or less, martensite and tempered martensite: more than 90.0% in total, and the balance: one or more of bainite, pearlite and retained austenite,
  • the orientation difference between adjacent martensite and tempered martensite is 15 deg.
  • the bond strength energy EGB determined by the concentration of each alloying element on the prior austenite grain boundary satisfies the following formula (1), and the tensile strength is 1500 MPa or more. .
  • EGB 1 + (3 x [Co] + 0.7 x [Ni] + 5.5 x [Mo] + 0.7 x [Cr] + 2.9 x [Ti] + 47 x [B] + 4.3 x [Nb] +4.5 ⁇ [V]+5.2 ⁇ [W]+3.1 ⁇ [Ta]+4.3 ⁇ [Zr] ⁇ 0.25 ⁇ [Mn] ⁇ 0.1 ⁇ [P] ⁇ [Cu] ⁇ 1 .1 ⁇ [Sn] ⁇ 0.6 ⁇ [Sb] ⁇ 0.9 ⁇ [As]) ⁇ 0.50 (1)
  • the [chemical symbol] in the formula represents the concentration of each alloying element in mass % on the prior austenite grain boundary.
  • the steel sheet according to [1] has the chemical composition of Co: 0.01 to 0.500%, Ni: 0.01 to 1.000%, Mo: 0.01 to 1.000%, Cr: 0.001-2.000%, Ti: 0.001-0.500%, B: 0.0001-0.0100%, Nb: 0.001-0.500%, V: 0.001- 0.500%, Cu: 0.001-0.500%, W: 0.001-0.100%, Ta: 0.001-0.100%, Mg: 0.001-0.050%, Ca : 0.001-0.050%, Y: 0.001-0.050%, Zr: 0.001-0.050%, La: 0.001-0.050%, Ce: 0.001-0 0.050%, Sn: 0.001 to 0.050%, Sb: 0.001 to 0.050%, and As: 0.001 to 0.050%, one or two selected from the group consisting of It may contain more than [3]
  • the steel sheet according to [1] or [2] may have a coating layer containing zinc, aluminum, magnesium or alloys thereof
  • FIG. 2 is a diagram showing the relationship between hydrogen embrittlement resistance of steel sheets, EGB , and tensile strength in Examples of the present invention.
  • a steel sheet according to one embodiment of the present invention (steel sheet according to the present embodiment) will be described below.
  • the steel plate according to the present embodiment has a predetermined chemical composition
  • the microstructure has an area ratio of ferrite: 5.0% or less, martensite and tempered martensite: more than 90.0% in total, and the balance: one or more of bainite, pearlite and retained austenite become,
  • the orientation difference between adjacent martensite and tempered martensite is 15 deg.
  • the bond strength energy EGB determined by the concentration of each alloying element on the prior austenite grain boundary is 0.50 or more
  • Tensile strength is 1500 MPa or more.
  • C 0.150-0.400% C is an effective element for inexpensively increasing tensile strength. If the C content is less than 0.150%, the target tensile strength cannot be obtained, and the fatigue properties of the weld zone deteriorate. Therefore, the C content is made 0.150% or more. The C content may be 0.160% or more, 0.180% or more, or 0.200% or more. On the other hand, if the C content exceeds 0.400%, the hydrogen embrittlement resistance and weldability deteriorate. Therefore, the C content is set to 0.400% or less. The C content may be 0.350% or less, 0.300% or less, or 0.250% or less.
  • Si 0.01-2.00% Si is an element that acts as a deoxidizing agent and affects the morphology of carbides and retained austenite after heat treatment. If the Si content is less than 0.01%, it becomes difficult to suppress the formation of coarse oxides. These coarse oxides serve as starting points for cracks, and the cracks propagate in the steel material, degrading the hydrogen embrittlement resistance. Therefore, the Si content is set to 0.01% or more. The Si content may be 0.05% or more, 0.10% or more, or 0.30% or more. On the other hand, if the Si content exceeds 2.00%, the precipitation of alloy carbides in the hot-rolled structure is delayed. Therefore, the Si content is set to 2.00% or less. The Si content may be 1.80% or less, 1.60% or less, or 1.40% or less.
  • Mn 0.80-2.00%
  • Mn is an element effective in increasing the strength of the steel sheet. If the Mn content is less than 0.80%, sufficient effects cannot be obtained. Therefore, the Mn content is set to 0.80% or more.
  • the Mn content may be 1.00% or more, or 1.20% or more.
  • the Mn content exceeds 2.00%, Mn not only promotes co-segregation with P and S, but also may deteriorate corrosion resistance and hydrogen embrittlement resistance. Therefore, the Mn content is set to 2.00% or less.
  • the Mn content may be 1.90% or less, 1.85% or less, or 1.80% or less.
  • P 0.0001 to 0.0200%
  • P is an element that strongly segregates at ferrite grain boundaries and promotes grain boundary embrittlement. If the P content exceeds 0.0200%, the hydrogen embrittlement resistance is remarkably lowered due to intergranular embrittlement. Therefore, the P content is set to 0.0200% or less.
  • the P content may be 0.0180% or less, 0.0150% or less, or 0.0120% or less. The lower the P content, the better. However, when the P content is less than 0.0001%, the time required for refining increases, resulting in a significant increase in cost. Therefore, the P content is made 0.0001% or more.
  • the P content may be 0.0005% or more, 0.0010% or more, or 0.0020% or more.
  • S is an element that forms nonmetallic inclusions such as MnS in steel. If the S content exceeds 0.0200%, the formation of non-metallic inclusions that serve as starting points for cracks during cold working becomes significant. In this case, even if the grain boundaries are strengthened, cracks are generated from the non-metallic inclusions, and the cracks propagate through the steel material, thereby deteriorating hydrogen embrittlement resistance. Therefore, the S content is set to 0.0200% or less. The S content may be 0.0180% or less, 0.0150% or less, or 0.0120% or less. The S content is preferably as small as possible.
  • the S content is made 0.0001% or more.
  • the S content may be 0.0005% or more, 0.0010% or more, or 0.0020% or more.
  • Al 0.001-1.000%
  • Al is an element that acts as a deoxidizing agent for steel and stabilizes ferrite. If the Al content is less than 0.001%, sufficient effects cannot be obtained. Therefore, the Al content is set to 0.001% or more.
  • the Al content may be 0.005% or more, 0.010% or more, or 0.020% or more.
  • coarse Al oxides are produced. This coarse oxide serves as a starting point for cracks. Therefore, when coarse Al oxides are formed, even if the grain boundaries are strengthened, cracks occur in the coarse oxides, and these cracks propagate through the steel material, degrading hydrogen embrittlement resistance. . Therefore, the Al content is set to 1.000% or less.
  • the Al content may be 0.950% or less, 0.900% or less, or 0.800% or less.
  • N 0.0001 to 0.0200%
  • N is an element that forms coarse nitrides in the steel sheet and reduces the hydrogen embrittlement resistance of the steel sheet.
  • N is an element that causes blowholes during welding. If the N content exceeds 0.0200%, the hydrogen embrittlement resistance deteriorates and the occurrence of blowholes becomes significant. Therefore, the N content is set to 0.0200% or less.
  • the N content may be 0.0180% or less, 0.0160% or less, or 0.0120% or less.
  • the N content is less than 0.0001%, the manufacturing cost increases significantly. Therefore, the N content is set to 0.0001% or more.
  • the N content may be 0.0005% or more, 0.0010% or more, or 0.0020% or more.
  • O 0.0001 to 0.0200%
  • O is an element that forms an oxide and deteriorates hydrogen embrittlement resistance.
  • oxides often exist as inclusions, and if they are present on the punched edge or cut surface, they form notch-like scratches or coarse dimples on the edge, resulting in stress concentration during heavy working. , become the starting point of crack formation, resulting in significant deterioration of workability.
  • the O content exceeds 0.0200%, the tendency of deterioration of workability becomes remarkable. Therefore, the O content is set to 0.0200% or less.
  • the O content may be 0.0180% or less, 0.0150% or less, or 0.0100% or less. The smaller the O content, the better.
  • the O content is set to 0.0001% or more.
  • the O content may be 0.0005% or more, 0.0010% or more, or 0.0015% or more.
  • the chemical composition of the steel sheet according to the embodiment of the present invention may include the above, with the balance being Fe and impurities.
  • the chemical composition of the steel sheet according to the present embodiment includes Co, Ni, Mo, Cr, Ti, B, Nb, and V as optional components instead of part of the remaining Fe. , Cu, W, Ta, Mg, Ca, Y, Zr, La, Ce, Sn, Sb, and As. Since these elements do not necessarily have to be contained, the lower limit is 0%. Moreover, even if the following elements are included as impurities, the effects of the steel sheet according to the present embodiment are not hindered.
  • Co is an effective element for controlling the morphology of carbides and increasing the strength of steel sheets.
  • Co is an element that also contributes to improving the bonding strength of grain boundaries. Therefore, Co may be contained.
  • the Co content is preferably 0.010% or more.
  • the Co content may be 0.020% or more, 0.050% or more, or 0.100% or more.
  • the Co content is set to 0.500% or less.
  • the Co content may be 0.450% or less, 0.400% or less, or 0.300% or less.
  • Ni is an element effective in increasing the strength of the steel sheet.
  • Ni is an element that also contributes to improving the bonding strength of grain boundaries.
  • Ni is an element effective in improving wettability and promoting an alloying reaction. Therefore, Ni may be contained.
  • the Ni content is preferably 0.010% or more.
  • the Ni content may be 0.020% or more, 0.050% or more, or 0.100% or more.
  • the Ni content is set to 1.000% or less.
  • the Ni content may be 0.900% or less, 0.800% or less, or 0.600% or less.
  • Mo 0-1.000%
  • Mo is an element effective in increasing the strength of the steel sheet.
  • Mo is an element that has the effect of suppressing ferrite transformation that occurs during heat treatment in continuous annealing equipment or continuous hot-dip galvanizing equipment.
  • Mo is also an element that contributes to improving the bonding strength of grain boundaries. Therefore, Mo may be contained.
  • the Mo content is preferably 0.010% or more.
  • the Mo content may be 0.020% or more, 0.050% or more, or 0.080% or more.
  • the Mo content exceeds 1.000%, the effect of suppressing ferrite transformation is saturated. Therefore, the Mo content is set to 1.000% or less.
  • the Mo content may be 0.900% or less, 0.800% or less, or 0.600% or less.
  • Cr 0 to 2.000% Cr, like Mn, is an element that suppresses pearlite transformation and is effective in increasing the strength of steel. Moreover, Cr is an element that also contributes to improving the bonding strength of grain boundaries. Therefore, Cr may be contained. When obtaining the above effect, it is preferable to set the Cr content to 0.001% or more. The Cr content may be 0.005% or more, 0.010% or more, or 0.050% or more. On the other hand, when the Cr content exceeds 2.000%, coarse Cr carbides are formed in the center segregation portion, which may deteriorate hydrogen embrittlement resistance. Therefore, the Cr content is set to 2.000% or less. The Cr content may be 1.800% or less, 1.500% or less, or 1.000% or less.
  • Ti 0-0.500%
  • Ti is an element that contributes to an increase in the strength of a steel sheet through strengthening of precipitates, strengthening of fine grains by suppressing the growth of ferrite grains, and strengthening of dislocations through suppression of recrystallization.
  • Ti is an element that contributes to improving the bonding strength of grain boundaries. Therefore, Ti may be contained.
  • the Ti content is preferably 0.001% or more.
  • the Ti content may be 0.003% or more, 0.010% or more, or 0.050% or more.
  • the Ti content exceeds 0.500%, the precipitation of carbonitrides increases and the hydrogen embrittlement resistance may deteriorate. Therefore, the Ti content is set to 0.500% or less.
  • the Ti content may be 0.450% or less, 0.400% or less, or 0.300% or less.
  • B 0 to 0.0100%
  • B is an element that suppresses the formation of ferrite and pearlite in the cooling process from the austenite temperature range and promotes the formation of a low temperature transformation structure such as bainite or martensite.
  • B is an element useful for increasing the strength of steel.
  • B is an element that also contributes to the improvement of the bonding strength of grain boundaries. Therefore, B may be contained.
  • the B content is preferably 0.0001% or more.
  • the B content may be 0.0003% or more, 0.0005% or more, or 0.0010% or more.
  • the B content exceeds 0.0100%, coarse B oxides are formed in the steel.
  • the B content is set to 0.0100% or less.
  • the B content may be 0.0080% or less, 0.0060% or less, or 0.0050% or less.
  • Nb 0-0.500% Nb, like Ti, is an element effective in controlling the morphology of carbides, and is also an element effective in improving toughness by refining the structure.
  • Nb is an element that contributes to improving the bonding strength of grain boundaries. Therefore, Nb may be contained.
  • the Nb content is preferably 0.001% or more.
  • the Nb content may be 0.002% or more, 0.010% or more, or 0.020% or more.
  • the Nb content exceeds 0.500%, the formation of coarse Nb carbides becomes significant. Since these coarse Nb carbides are likely to crack, the formation of coarse Nb carbides may deteriorate the hydrogen embrittlement resistance. Therefore, the Nb content is set to 0.500% or less.
  • the Nb content may be 0.450% or less, 0.400% or less, or 0.300% or less.
  • V 0-0.500%
  • V is an element that contributes to an increase in the strength of a steel sheet through strengthening of precipitates, strengthening of fine grains by suppressing the growth of ferrite grains, and strengthening of dislocations through suppression of recrystallization.
  • V is an element that also contributes to improving the bonding strength of grain boundaries. Therefore, V may be contained.
  • the V content is preferably 0.001% or more.
  • the V content may be 0.002% or more, 0.010% or more, or 0.020% or more.
  • the V content is set to 0.500% or less.
  • the V content may be 0.450% or less, 0.400% or less, or 0.300% or less.
  • Cu 0-0.500%
  • Cu is an element effective in improving the strength of the steel sheet. If the Cu content is less than 0.001%, sufficient effects cannot be obtained. Therefore, in order to obtain the above effect, the Cu content is preferably 0.001% or more.
  • the Cu content may be 0.002% or more, 0.010% or more, or 0.030% or more.
  • the Cu content exceeds 0.500%, the hydrogen embrittlement resistance may deteriorate.
  • the Cu content is set to 0.500% or less.
  • the Cu content may be 0.450% or less, 0.400% or less, or 0.300% or less.
  • W 0-0.100% W is an element effective in increasing the strength of the steel sheet. Moreover, W forms precipitates and crystallized substances. Since precipitates and crystallized substances containing W become hydrogen trap sites, W is an element effective in improving hydrogen embrittlement resistance. In addition, W is an element that contributes to improving the bonding strength of grain boundaries. Therefore, W may be contained. In order to obtain the above effects, the W content is preferably 0.001% or more. The W content may be 0.002% or more, 0.005% or more, or 0.010% or more. On the other hand, when the W content exceeds 0.100%, the formation of coarse W precipitates or crystallized substances becomes significant.
  • the W content is set to 0.100% or less.
  • the W content may be 0.080% or less, 0.060% or less, or 0.050% or less.
  • Ta 0-0.100% Ta, like Nb, V, and W, is an element effective in controlling the morphology of carbides and increasing the strength of the steel sheet.
  • Ta is an element that also contributes to improving the bonding strength of grain boundaries. Therefore, Ta may be contained.
  • the Ta content is preferably 0.001% or more.
  • the Ta content may be 0.002% or more, 0.005% or more, or 0.010% or more.
  • the Ta content exceeds 0.100%, a large number of fine Ta carbides are precipitated, and as the strength of the steel sheet increases, ductility may decrease, and bending resistance and hydrogen embrittlement resistance may decrease. There is Therefore, the Ta content is set to 0.100% or less.
  • the Ta content may be 0.080% or less, 0.060% or less, or 0.050% or less.
  • Mg 0-0.050% Mg is an element that can control the morphology of sulfides with a very small amount of content. Therefore, Mg may be contained. To obtain the above effects, the Mg content is preferably 0.001% or more. The Mg content may be 0.005% or more, 0.010% or more, or 0.020% or more. On the other hand, if the Mg content exceeds 0.050%, coarse inclusions may be formed and the hydrogen embrittlement resistance may deteriorate. Therefore, the Mg content is set to 0.050% or less. The Mg content may be 0.040% or less, 0.030% or less, or 0.020% or less.
  • Ca 0-0.050% Ca is an element that is useful as a deoxidizing element and also effective in controlling the morphology of sulfides. Therefore, Ca may be contained. When obtaining the above effect, it is preferable to set the Ca content to 0.001% or more.
  • the Ca content may be 0.002% or more, 0.004% or more, or 0.006% or more.
  • the Ca content is set to 0.050% or less.
  • the Ca content may be 0.040% or less, 0.030% or less, or 0.020% or less.
  • Y 0 to 0.050% Y, like Mg and Ca, is an element capable of controlling the morphology of sulfides when contained in a very small amount. Therefore, Y may be contained.
  • the Y content is preferably 0.001% or more.
  • the Y content may be 0.002% or more, 0.004% or more, or 0.006% or more.
  • the Y content is set to 0.050% or less.
  • the Y content may be 0.040% or less, 0.030% or less, or 0.020% or less.
  • Zr 0-0.050% Zr, like Mg, Ca, and Y, is an element capable of controlling the morphology of sulfides when contained in a trace amount.
  • Zr is an element that contributes to improving the bonding strength of grain boundaries. Therefore, Zr may be contained.
  • the Zr content is preferably 0.001% or more.
  • the Zr content may be 0.002% or more, 0.004% or more, or 0.006% or more.
  • the Zr content is set to 0.050% or less.
  • the Zr content may be 0.040% or less, 0.030% or less, or 0.020% or less.
  • La 0-0.050%
  • La is an element capable of controlling the morphology of sulfides when contained in a trace amount. Therefore, La may be contained.
  • the La content is preferably 0.001% or more.
  • the La content may be 0.002% or more, 0.004% or more, or 0.006% or more.
  • the La content is set to 0.050% or less.
  • the La content may be 0.040% or less, 0.030% or less, or 0.020% or less.
  • Ce 0-0.050% Ce, like La, is an element capable of controlling the morphology of sulfides when contained in a trace amount. Therefore, Ce may be contained.
  • the Ce content is preferably 0.001% or more.
  • the Ce content may be 0.002% or more, 0.004% or more, or 0.006% or more.
  • the Ce content is set to 0.050% or less.
  • the Ce content may be 0.040% or less, 0.030% or less, or 0.020% or less.
  • Sn 0-0.050%
  • Sn is an element contained in steel when scrap is used as a raw material.
  • the Sn content may be 0.040% or less, 0.030% or less, or 0.020% or less.
  • the Sn content is preferably as small as possible and may even be 0%, but if the Sn content is less than 0.001%, the refining cost increases. Therefore, the Sn content may be 0.001% or more.
  • the Sn content may be 0.002% or more, 0.005% or more, or 0.010% or more.
  • Sb 0-0.050% Sb, like Sn, is an element contained when scrap is used as a raw material for steel.
  • Sb is an element that strongly segregates at grain boundaries and causes grain boundary embrittlement and ductility deterioration. This adverse effect is particularly noticeable when the Sb content exceeds 0.050%. Therefore, the Sb content is set to 0.050% or less.
  • the Sb content may be 0.040% or less, 0.030% or less, or 0.020% or less.
  • the Sb content is preferably as small as possible and may even be 0%, but if the Sb content is less than 0.001%, the refining cost increases. Therefore, the Sb content may be 0.001% or more.
  • the Sb content may be 0.002% or more, 0.005% or more, or 0.008% or more.
  • As 0-0.050% Like Sn and Sb, As is contained when scrap is used as a raw material for steel, and is an element that strongly segregates at grain boundaries and causes grain boundary embrittlement and a decrease in ductility. If the As content is high, the hydrogen embrittlement resistance may deteriorate. This adverse effect is particularly noticeable when the As content exceeds 0.050%. Therefore, the As content is set to 0.050% or less.
  • the As content may be 0.040% or less, 0.030% or less, or 0.020% or less.
  • the As content is preferably as low as possible and may even be 0%, but if the As content is less than 0.001%, the refining cost increases. Therefore, the As content may be 0.001% or more.
  • the As content may be 0.002% or more, 0.003% or more, or 0.005% or more.
  • the chemical composition of the steel sheet according to the present embodiment contains basic ingredients, the balance may be Fe and impurities, contains basic ingredients, and contains one or more optional ingredients, The balance may consist of Fe and impurities.
  • the chemical composition of the steel sheet according to this embodiment may be measured by a general method. For example, it may be measured using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry) for chips according to JIS G1201:2014. In this case, the chemical composition is the average content over the entire plate thickness. Cannot be measured by ICP-AES, C and S are measured using the combustion-infrared absorption method, N is measured using the inert gas fusion-thermal conductivity method, and O is measured using the inert gas fusion-nondispersive infrared absorption method. do it.
  • the chemical composition may be analyzed after removing the coating layer by mechanical grinding or the like. When the coating layer is a plated layer, it may be removed by dissolving the plated layer in an acid solution containing an inhibitor for suppressing corrosion of the steel sheet.
  • the microstructure is the microstructure at a position within a range of 1/8 to 3/8 (t/4 part) of the plate thickness in the plate thickness direction from the surface of the steel plate.
  • the reason why the t/4 part microstructure is specified is that it is a typical microstructure of the steel sheet and is highly correlated with the properties of the steel sheet.
  • the fraction (%) of each phase below is the area ratio unless otherwise specified.
  • Ferrite 5.0% or less Ferrite affects the deformability of steel having a martensite-based structure. As the ferrite area ratio increases, the local deformability and hydrogen embrittlement resistance decrease. In particular, when the area ratio of ferrite exceeds 5.0%, the hydrogen embrittlement resistance may deteriorate due to fracture due to elastic deformation under stress load. Therefore, the area ratio of ferrite is set to 5.0% or less.
  • the area ratio of ferrite may be 4.0% or less, 3.0% or less, or 2.0% or less.
  • the area ratio of ferrite may be 0%, but if it is less than 1.0%, a high level of control is required in manufacturing, resulting in a decrease in yield. Therefore, the area ratio of ferrite may be 1.0% or more.
  • Martensite and tempered martensite more than 90.0% in total
  • the total area ratio of martensite and tempered martensite affects the strength of steel, and the larger the area ratio, the higher the tensile strength. If the total area ratio of martensite and tempered martensite is 90.0% or less, the target tensile strength cannot be achieved. In addition, it may cause fracture during elastic deformation under stress load, or cause deterioration of hydrogen embrittlement resistance due to the formation of structures other than martensite and tempered martensite and increased non-uniformity of the microstructure. may be. Therefore, the total area ratio of martensite and tempered martensite is set to more than 90.0%.
  • the total area percentage of martensite and tempered martensite may be 95.0% or more, 97.0% or more, 99.0% or more, or 100.0%.
  • the area ratio of structures other than the above structures may be 0%, but if there is a remaining structure, the remaining structure consists of one or more of bainite, pearlite and retained austenite. If the area ratio of the residual structure exceeds 8.0%, fracture may occur due to elastic deformation when stress is applied, and hydrogen embrittlement resistance may deteriorate. Therefore, the area ratio of the residual tissue is preferably 8.0% or less, more preferably 7.0% or less. Among them, particularly pearlite and retained austenite are structures that deteriorate the local ductility of steel, and the smaller the content, the better. On the other hand, in order to make the area ratio of the remaining structure 0%, a high degree of control is required in manufacturing, which may lead to a decrease in yield. Therefore, the area ratio of the remaining structure may be 1.0% or more.
  • the area ratio of each phase in the microstructure of the steel sheet according to this embodiment can be obtained by the following method.
  • Electron channeling contrast image is a method of detecting the crystal orientation difference in the crystal grain as the difference in image contrast, and in the image, it is determined that it is ferrite instead of pearlite, bainite, martensite, and retained austenite. A portion of the tissue that appears with uniform contrast is polygonal ferrite. Eight fields of electron channeling contrast images of 35 ⁇ m ⁇ 25 ⁇ m are analyzed by image analysis to calculate the area ratio of polygonal ferrite in each field, and the average value is defined as the area ratio of ferrite.
  • Tempered martensite is an aggregate of lath-shaped crystal grains, containing iron-based carbides with a major axis of 20 nm or more inside, and the carbides belong to multiple variants, that is, multiple iron-based carbide groups extending in different directions. is.
  • retained austenite also exists in convex portions on the structure observation surface. Therefore, by subtracting the area ratio of the protrusions obtained in the above procedure by the area ratio of retained austenite measured in the procedure described later, the total area ratio of martensite and tempered martensite can be correctly measured. becomes.
  • the area ratio of retained austenite can be calculated by X-ray measurement. That is, the sample is removed by mechanical polishing and chemical polishing from the plate surface of the sample to the position of 1/4 of the plate thickness in the plate thickness direction. Diffraction peaks of (200), (211) of the bcc phase and (200), (220), (311) of the fcc phase obtained using MoK ⁇ rays as characteristic X-rays for the polished sample From the integrated intensity ratio of , the structure fraction of retained austenite is calculated, and this is defined as the area ratio of retained austenite. For perlite, the area ratio is determined from the image captured by the electronic channeling contrast described above.
  • Pearlite is a structure in which plate-like carbides and ferrite are arranged side by side.
  • bainite is an aggregate of lath-shaped crystal grains that does not contain iron-based carbides with a major axis of 20 nm or more inside, or contains iron-based carbides with a major axis of 20 nm or more inside, and the carbide is a single variants, i.e. belonging to the group of iron-based carbides elongated in the same direction.
  • the iron-based carbide group extending in the same direction means that the difference in the extending direction of the iron-based carbide group is within 5°.
  • the present inventors have found that in the microstructure mainly composed of martensite and tempered martensite, the misorientation between adjacent martensite and tempered martensite is 15 deg.
  • the above interfaces (martensite/tempered martensite, martensite/martensite, or tempered martensite/tempered martensite interfaces) are the main grain boundaries, and the grain boundary strength is improved by each alloying element.
  • We investigated the contribution of As a result when the bond strength energy EGB can be expressed by the following formula (1) using the concentration of each alloy element on the grain boundary, and when EGB is 0.50 or more, the hydrogen embrittlement resistance is A clear improvement was found. Therefore, in the steel sheet according to the present embodiment, the orientation difference between adjacent martensite and tempered martensite is 15 deg.
  • the bond strength energy E GB determined by the concentration of each alloying element on the prior austenite grain boundary satisfies the following formula (1).
  • EGB 1 + (3 x [Co] + 0.7 x [Ni] + 5.5 x [Mo] + 0.7 x [Cr] + 2.9 x [Ti] + 47 x [B] + 4.3 x [Nb] +4.5 ⁇ [V]+5.2 ⁇ [W]+3.1 ⁇ [Ta]+4.3 ⁇ [Zr] ⁇ 0.25 ⁇ [Mn] ⁇ 0.1 ⁇ [P] ⁇ [Cu] ⁇ 1 .1 ⁇ [Sn] ⁇ 0.6 ⁇ [Sb] ⁇ 0.9 ⁇ [As]) ⁇ 0.50
  • the [chemical symbol] in the formula represents the concentration of each alloying element in mass % on the prior austenite grain boundary.
  • the orientation difference is 15deg. 15deg. This is because hydrogen tends to preferentially accumulate at the former austenite grain boundaries. As can be seen from the formula (1), not all the alloying elements that segregate at the grain boundaries increase the bond strength energy, but the segregation of many alloying elements that increase the grain boundary bonding energy increases the grain boundary bonding energy. .
  • the orientation difference between adjacent martensite and tempered martensite is 15 deg.
  • the above interface is an interface between martensite and martensite, and the orientation difference is 15 deg.
  • the interface described above, which is the interface between martensite and tempered martensite, has a misorientation of 15 deg.
  • the concentration of each alloying element on the prior austenite grain boundary was measured using an EDS (energy dispersive X-ray spectrometer) of a TEM (transmission electron microscope) in the same manner as the SEM observation described above. It is obtained by observing the thickness (range of 1/8 to 3/8 of the plate thickness centering on the position of 1/4 of the plate thickness in the thickness direction). More specifically, a TEM transmission electron microscope (Cs-corrected TEM) with spherical aberration correction is used as the TEM (transmission electron microscope). A thin section sample used for TEM observation is obtained by the following method.
  • a sample for measuring the amount of alloying elements is taken from a steel plate sample in the range of 1/8 to 3/8 of the plate thickness, and wet-polished using emery paper to a thickness of about 100 ⁇ m.
  • electrolytic polishing is performed by twin-jet electrolytic polishing to a thinness that allows TEM observation.
  • the electropolishing method is performed using a twin-jet electropolishing apparatus. Since the appropriate conditions for twin-jet electropolishing vary depending on the composition of the base material of the sample, it is necessary to extract the conditions for each sample. Uniform milling of the flake sample using Ar ion milling after twin jet improves the quantification accuracy of the elements on the prior austenite grain boundaries.
  • the flake sample thus obtained is observed with a Cs-corrected TEM.
  • the observation position is on the former austenite grain boundary, and the former austenite grain boundary is found as follows.
  • the former austenite grain boundaries, packet boundaries and block boundaries appear as black lines.
  • the sample is tilted and rotated so that any black line indicating the prior austenite grain boundary is horizontal to the electron beam incident direction of the TEM.
  • elemental analysis using EDS is performed at 100,000 times just above the prior austenite grain boundary.
  • the elemental analysis using the cumulative number of times of EDS analysis is performed by the following method.
  • Point analyzes are performed three times just above the prior austenite grain boundaries to quantify the concentration of alloying elements on the prior austenite grain boundaries. This analysis is performed on five prior austenite grain boundaries to calculate the average alloying element concentration. This average alloying element concentration is defined as the alloying element concentration on the prior austenite grain boundary.
  • the steel sheet according to the present embodiment has a tensile strength (TS) of 1500 MPa or more as a strength contributing to weight reduction of automobile bodies. Although there is no need to limit the upper limit, if the tensile strength increases, the moldability may decrease, so the tensile strength may be 2000 MPa or less.
  • TS tensile strength
  • the thickness of the steel sheet according to the present embodiment is not limited, it is preferably 1.0 to 2.2 mm. More preferably, the plate thickness is 1.05 mm or more, still more preferably 1.1 mm or more. Also, the plate thickness is more preferably 2.1 mm or less, more preferably 2.0 mm or less.
  • the steel sheet according to this embodiment may have a coating layer containing zinc, aluminum, magnesium or alloys thereof on one or both surfaces.
  • This coating layer may consist of zinc, aluminum, magnesium or alloys thereof and impurities. Corrosion resistance is improved by providing a coating layer on the surface.
  • Steel sheets for automobiles may not be thinned to a certain thickness or less even if they are strengthened due to concerns about perforation due to corrosion.
  • One of the purposes of increasing the strength of steel sheets is to reduce the weight by making them thinner. Therefore, even if a high-strength steel sheet is developed, its application is limited if the corrosion resistance is low.
  • the coating layer is, for example, a hot dip galvanizing layer, an alloyed hot dip galvanizing layer, an electrogalvanizing layer, an aluminum plating layer, a Zn-Al alloy plating layer, an Al-Mg alloy plating layer, or a Zn-Al-Mg alloy plating layer.
  • the reference surface of the t/4 part described above is the surface of the base iron excluding the coating layer.
  • the steel plate according to the present embodiment can be produced by a production method including the following steps (I) to (VII), although the steel plate according to the present embodiment can obtain the above effects regardless of the production method.
  • a cooling step of cooling to temperature (IV) a winding step of winding the hot-rolled steel sheet after the cooling step at the winding temperature; (V) a stopping step of stopping the hot-rolled steel sheet after the winding step in a temperature range of 400 to 550° C. for 600 seconds or longer; (VI) a cold-rolling step of pickling and cold-rolling the hot-rolled steel sheet after the stopping step to obtain a cold-rolled steel sheet; (VII) An annealing step of holding and annealing the cold-rolled steel sheet after the cold-rolling step at an annealing temperature of 800°C or more and less than 900°C. Preferred conditions in each step are described below.
  • Heating process a steel piece such as a slab having the same chemical composition as the steel plate according to the present embodiment is heated prior to hot rolling.
  • the heating temperature is not limited as long as the rolling temperature for the next step can be ensured. For example, it is 1000 to 1300°C.
  • the steel slabs to be used are preferably cast by continuous casting from the viewpoint of productivity, but may be produced by ingot casting or thin slab casting.
  • the heating step may be omitted if the steel slab obtained by continuous casting can be subjected to the hot rolling step at a sufficiently high temperature.
  • the hot rolling step includes rough rolling and finish rolling, and in the finish rolling, a plurality of passes are reduced, and among the plurality of passes, 4 or more passes are large reduction passes with a reduction rate of 20% or more,
  • the time between each high reduction pass shall be 5.0 seconds or less.
  • the rolling start temperature is set to 950 to 1100°C
  • the rolling end temperature is set to 800 to 950°C.
  • the reduction ratio is set to 20% or more (four passes or more are performed with a reduction ratio of 20% or more).
  • the reduction rate is set to 20% or more in 5 or more passes.
  • the upper limit of the number of passes with a rolling reduction of 20% or more is not particularly limited. There is therefore, the number of passes (the number of passes) with a reduction rate of 20% or more may be 10 passes or less, 9 passes or less, or 7 passes or less.
  • the time between passes in finish rolling has a great effect on recrystallization and grain growth of austenite grains after rolling.
  • the hot rolled steel sheet after the hot rolling step is cooled within 3.0 seconds from the completion of the hot rolling step (completion of the final pass of finish rolling), Cool to a coiling temperature of 550-700° C. at an average cooling rate of less than a second. If the time from the completion of hot rolling to the start of rolling exceeds 3.0 seconds, or if the average cooling rate to the coiling temperature is less than 20°C/sec, an austenite to ferrite transformation will occur before coiling. In this case, the driving force of the precipitate becomes small, and it becomes difficult to deposit the precipitate uniformly and finely in the subsequent process.
  • the cooling stop temperature exceeds 700°C, an internal oxide layer is likely to be formed on the surface of the steel sheet, cracks are likely to occur on the surface, and the productivity in the subsequent pickling process is significantly deteriorated, which is not preferable. . It is not necessary to limit the lower limit of the time from the completion of hot rolling to the start of rolling.
  • the hot-rolled steel sheet after the cooling process is coiled at a coiling temperature (cooling stop temperature).
  • the wound hot-rolled steel sheet is held (held) in a temperature range of 400 to 550° C. for 600 seconds or longer.
  • alloy carbides or nitrides are precipitated on the steel sheet.
  • the precipitates deposited here can be unevenly distributed at the prior austenite grain boundaries by controlling the post-process. If the holding temperature is too high, the precipitates are coarsened and not uniformly dispersed.
  • the holding temperature is too low, although the precipitates become finer, it takes a long time to complete the precipitation, resulting in lower manufacturability and productivity. Also, if the holding time is short, the alloy carbides will not precipitate sufficiently.
  • a method such as covering or covering with a heating box may be performed.
  • Cold rolling process In the cold-rolling process, the hot-rolled steel sheet after the stopping process is unwound, pickled and cold-rolled to obtain a cold-rolled steel sheet. By pickling, the oxide scale on the surface of the hot-rolled steel sheet can be removed, and the chemical conversion treatability and platability of the cold-rolled steel sheet can be improved.
  • the pickling may be carried out under known conditions, and may be carried out once or in multiple batches.
  • the rolling reduction (rolling rate) of cold rolling is not particularly limited. For example, 20-80%.
  • the cold-rolled steel sheet after the cold rolling step is annealed while being held at an annealing temperature of 800°C or more and less than 900°C.
  • this annealing step in the process of heating to the annealing temperature, which is in the austenite single-phase region, these precipitates play a role of pinning prior austenite grain boundaries in a relatively low temperature region. As a result, the precipitates are unevenly distributed on the prior austenite grain boundaries. When the temperature is further heated to reach a relatively high temperature range, the precipitate becomes thermally unstable and dissolves. As a result, the alloy elements can be segregated on the prior austenite grain boundaries.
  • the annealing temperature is set to 800° C. or higher.
  • Annealing temperature is preferably 830° C. or higher.
  • the annealing temperature is 900° C.
  • the holding time is preferably 10 seconds or longer.
  • the average heating rate to the annealing temperature is preferably 2 to 35°C/sec.
  • the cold-rolled steel sheet may be cooled from the annealing temperature to 25°C to 300°C at an average cooling rate of 20°C to 100°C/sec.
  • the steel sheet is quenched in a state in which alloying elements are segregated in the austenite grain boundaries, and austenite transforms into martensite.
  • the average cooling rate is less than 20°C/sec, a sufficient amount of martensite will not form.
  • the average cooling rate exceeds 100°C/sec
  • the capacity of the equipment may be insufficient for continuous annealing, and the equipment may need to be reinforced, so 100°C/sec is the substantial upper limit.
  • the cooling stop temperature exceeds 300° C.
  • untransformed austenite that has not undergone martensitic transformation tends to undergo bainite transformation, which may lead to a decrease in strength.
  • the cooling stop temperature is set to less than 25° C., the effect is saturated, and a special refrigerant or the like is required, which lowers the productivity and increases the cost.
  • the cold-rolled steel sheet after the post-annealing cooling step may be further subjected to a tempering step of heating to 50 to 550° C. and holding for 10 to 1000 seconds.
  • a tempering step of heating to 50 to 550° C. and holding for 10 to 1000 seconds.
  • tempering temperature when the tempering temperature is higher than 550°C, the dislocation density in the tempered martensite decreases, resulting in a decrease in strength, which may lead to a decrease in tensile strength.
  • carbides may be coarsely precipitated on prior austenite grain boundaries, degrading hydrogen embrittlement resistance.
  • the holding time when the holding time is longer than 1000 seconds, the strength is lowered and the productivity is lowered. Tempering may be performed in a continuous annealing facility, or off-line after continuous annealing in a separate facility.
  • the steel In the post-annealing cooling step, the steel may be held in a temperature range of 350 to 650° C. (second temperature range: a temperature range considered to be higher than the Ms point) for 10 to 200 seconds during cooling.
  • the cooling rate up to the second temperature range, excluding the holding temperature, and the average cooling rate from the holding temperature to 25 to 300° C. (cooling stop temperature) may each be 20 to 100° C./sec. That is, in this case, after the annealing step, cooling is performed from the annealing temperature to the second temperature range of 350 to 650 ° C. at an average cooling rate of 20 to 100 ° C./sec, and the second temperature range is for 10 to 200 seconds.
  • the alloying elements that cannot be completely segregated at the grain boundaries and are present in the grains are segregated on the prior austenite grain boundaries, and the hydrogen embrittlement resistance can be improved.
  • the holding temperature is less than 350° C., bainite transformation is likely to occur, and strength may decrease. If the holding time is less than 20 seconds, the effect of segregating the elements present in the grains onto the prior austenite grain boundaries cannot be obtained.
  • the holding temperature range is preferably 370° C. or higher and 630° C. or lower, more preferably 390° C. or higher and 610° C. or lower.
  • the holding time range is preferably 30 seconds or more and 180 seconds or less, more preferably 50 seconds or more and 160 seconds or less.
  • the steel sheet manufacturing method may include a coating layer forming step of forming a coating layer on (one or both) surfaces of the steel sheet.
  • a coating layer containing zinc, aluminum, magnesium or alloys thereof is preferable.
  • the coating layer is, for example, a plated layer.
  • the coating method is not limited, for example, when forming a coating layer mainly composed of zinc by hot-dip plating, the cold-rolled steel sheet is heated so that the steel sheet temperature is (plating bath temperature -40) ° C. to (plating bath temperature +50) ° C. , and then immersed in a plating bath at 450 to 490° C. to form a plating layer.
  • the composition of the plating bath is such that the effective Al amount (the value obtained by subtracting the total amount of Fe from the total amount of Al in the plating bath) is 0.050 to 0.250% by mass. , and optionally Mg, with the balance being Zn and impurities.
  • the effective Al content in the plating bath is less than 0.050% by mass, Fe may excessively penetrate into the plating layer, resulting in deterioration of plating adhesion.
  • the effective Al amount in the plating bath exceeds 0.250% by mass, an Al-based oxide that inhibits the movement of Fe atoms and Zn atoms is generated at the boundary between the steel sheet and the coating layer, resulting in poor coating adhesion. may decrease.
  • the coating layer may be formed after the post-annealing cooling process, during the post-annealing cooling process, or during the tempering process. That is, as part of the 350-650° C. hold during the post-annealing cooling step, or as part of the 50-550° C. hold during the tempering step.
  • alloying treatment may be further performed.
  • a condition is exemplified in which the steel sheet on which the plating layer is formed is held at 480 to 550° C. for 1 to 30 seconds.
  • the alloying step may also be performed during the post-annealing cooling step described above, or during the tempering step. That is, as part of the 350-650° C. hold during the post-annealing cooling step, or as part of the 50-550° C. hold during the tempering step.
  • the surface of the coating layer is subjected to an upper layer plating, various treatments such as chromate treatment, phosphate treatment, lubricity improvement treatment, weldability improvement treatment, etc. can also be used.
  • Example 1 Steel having the chemical compositions shown in Tables 1-1 to 1-4 was melted and cast into steel slabs. This steel slab was inserted into a furnace heated to 1220° C., held for 60 minutes, taken out into the atmosphere, and hot rolled to obtain a steel plate (hot rolled steel plate) having a thickness of 2.8 mm. In hot rolling, a rolling mill with 7 stands is used to perform a total of 7 finishing rollings continuously (so that the time between passes is constant). I gave 4 passes. In addition, the interpass time between each rolling pass that gives a rolling reduction of 20% or more in the finish rolling and the rolling pass that is one before the respective rolling pass was set to 0.6 seconds.
  • the starting temperature of finish rolling was 1060°C, and the finishing temperature was 870°C.
  • the hot-rolled steel sheet was cooled by water cooling, and cooled to 580°C at an average cooling rate of 38.0°C/second. °C furnace and held for 1800 seconds. Subsequently, the hot-rolled steel sheet was pickled to remove oxide scales, and cold-rolled at a rolling reduction of 50.0% to obtain a cold-rolled steel sheet having a thickness of 1.4 mm.
  • This cold-rolled steel sheet was heated to 880°C at an average heating rate of 12.0°C/sec, held at 880°C for 120 seconds, and then cooled to 150°C at an average cooling rate of 42.0°C/sec. After that, the cold-rolled steel sheet was subjected to tempering by reheating to 230° C. and holding for 180 seconds. No plating was applied.
  • the chemical composition was analyzed using samples taken from the obtained steel plate. As a result, the chemical compositions were the same as those of the steels shown in Tables 1-1 to 1-4.
  • the tensile strength, total elongation, and hydrogen embrittlement resistance (hydrogen embrittlement resistance) of the obtained cold-rolled steel sheets were evaluated by the following methods.
  • the tensile test conforms to JIS Z 2241 (2011), and the longitudinal direction of the test piece is parallel to the rolling direction of the steel strip. (El) was measured.
  • TS tensile strength
  • the obtained U-bending test piece was immersed in an HCl aqueous solution having a pH of 2 at a liquid temperature of 25° C. and held for 96 hours to examine the presence or absence of cracks.
  • the lower the pH of the HCl aqueous solution and the longer the immersion time the greater the amount of hydrogen that penetrates into the steel sheet, so the hydrogen embrittlement environment becomes a severe condition.
  • a case of NG was regarded as a failure.
  • a steel sheet with a tensile strength of 1500 MPa or more and a good evaluation of hydrogen embrittlement resistance was evaluated as a steel sheet with high strength and excellent resistance to hydrogen embrittlement.
  • production No. P had a low tensile strength of less than 1500 MPa due to its low C content.
  • Manufacturing No. S had a low tensile strength of less than 1500 MPa due to its low Mn content.
  • Example 2 Furthermore, in order to investigate the influence of the manufacturing conditions, the steel grades (steel Nos. A to O) that were found to have excellent properties in Example 1 were used in the same equipment as in Example 1, and steel billets were processed to 1250 to 1100. It was inserted into a furnace heated to 100°C, held for 60 minutes, and then taken out into the atmosphere to produce a hot-rolled steel sheet with a thickness of 2.3 mm under the manufacturing conditions shown in Tables 3-1 and 3-2. Further, cold-rolled steel sheets were obtained under the conditions after winding as described in Tables 3-1 to 3-4. A part of the cold-rolled steel sheet was a plated steel sheet having a plating layer.
  • GI and GA of the plating treatment indicate the method of galvanizing treatment
  • GI is a steel sheet formed by immersing the steel sheet in a hot dip galvanizing bath at 460 ° C. to form a galvanized layer on the surface of the steel sheet.
  • GA are steel sheets obtained by immersing the steel sheets in a hot-dip galvanizing bath and heating the steel sheets to 485° C. to form an iron-zinc alloy layer on the surface of the steel sheets.
  • examples in which tempering is indicated as "-" are examples in which tempering is not applied.
  • the time between passes in the table is the time between passes for each pass with a rolling reduction of 20% or more (since rolling was performed with a tandem rolling mill, the time between passes was the same).
  • the holding time in the post-annealing cooling step is the holding time in the second temperature range when cooling is performed to the second temperature range, but cooling is stopped. If the temperature is outside the second temperature range, it is the retention time around that temperature.
  • Example 2 For the obtained cold-rolled steel sheet (including plated steel sheet), in the same manner as in Example 1, ferrite, martensite and tempered martensite in the microstructure, and the balance (bainite, pearlite and retained austenite one or more of ) was determined, the concentration of each alloying element on the austenite grain boundary was measured, and EGB was determined.
  • Example 1 In addition, the tensile strength and total elongation of the obtained cold-rolled steel sheets were evaluated in the same manner as in Example 1.
  • TS tensile strength
  • the obtained U-bending test piece was immersed in an HCl aqueous solution having a pH of 2 at a liquid temperature of 25° C. and held for 96 hours to examine the presence or absence of cracks.
  • the total length of cracks in the U-bend test piece was measured (when multiple cracks were found, the sum of the values measured individually) was measured. The smaller the total length of the cracks, the better the hydrogen embrittlement resistance.
  • steel sheets with high strength and excellent resistance to hydrogen embrittlement can be obtained by appropriately controlling hot rolling, coiling, annealing, and the like. rice field.
  • FIG. 1 is a diagram showing the relationship between EGB and tensile strength given to hydrogen embrittlement resistance of steel sheets in Examples 1 and 2.
  • FIG. 1 ⁇ indicates an example in which the target for resistance to hydrogen embrittlement was not achieved, and ⁇ indicates an example in which the target for resistance to hydrogen embrittlement was achieved.
  • ⁇ indicates an example in which the target for resistance to hydrogen embrittlement was achieved.
  • FIG. 1 by setting the EGB to 0.50 or more, it is possible to obtain excellent resistance to hydrogen embrittlement even with a high-strength material of 1500 MPa or more.
  • the present invention it is possible to provide a high-strength steel sheet with excellent resistance to hydrogen embrittlement.
  • this steel sheet When this steel sheet is applied to steel sheets for automobiles, it contributes to weight reduction of the vehicle body and improvement of fuel efficiency.

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)

Abstract

La présente plaque d'acier a une composition chimique prescrite, la microstructure comprenant, par rapport de surface, 5,0 % ou moins de ferrite et un total supérieur à 90,0 % de martensite et de martensite revenue, le reste étant constitué d'une ou de plusieurs bainite, perlite, et de l'austénite résiduelle, et lorsqu'une limite pour laquelle la différence d'orientation entre la martensite adjacente et la martensite revenue est de 15 degrés ou plus est définie comme limite de grain d'austénite antérieure, l'énergie de force de liaison EGB, telle que déterminée par la concentration de chaque élément d'alliage sur la limite de grain d'austénite antérieure, est de 0,50 ou plus, et la résistance à la traction est de 1500 MPa ou plus.
PCT/JP2022/039380 2021-10-21 2022-10-21 Tôle d'acier WO2023068369A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202280070217.2A CN118140000A (zh) 2021-10-21 2022-10-21 钢板
KR1020247012403A KR20240069758A (ko) 2021-10-21 2022-10-21 강판

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2021-172424 2021-10-21
JP2021172424 2021-10-21

Publications (1)

Publication Number Publication Date
WO2023068369A1 true WO2023068369A1 (fr) 2023-04-27

Family

ID=86058328

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2022/039380 WO2023068369A1 (fr) 2021-10-21 2022-10-21 Tôle d'acier

Country Status (3)

Country Link
KR (1) KR20240069758A (fr)
CN (1) CN118140000A (fr)
WO (1) WO2023068369A1 (fr)

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006207019A (ja) 2004-12-28 2006-08-10 Kobe Steel Ltd 耐水素脆化特性及び加工性に優れた超高強度薄鋼板
JP2010138489A (ja) 2008-11-17 2010-06-24 Jfe Steel Corp 引張強さが１５００ＭＰａ以上の高強度鋼板およびその製造方法
JP2010215958A (ja) 2009-03-16 2010-09-30 Jfe Steel Corp 曲げ加工性および耐遅れ破壊特性に優れる高強度冷延鋼板およびその製造方法
JP2011179030A (ja) 2010-02-26 2011-09-15 Jfe Steel Corp 曲げ性に優れた超高強度冷延鋼板
JP2016050343A (ja) 2014-08-29 2016-04-11 新日鐵住金株式会社 耐水素脆化特性に優れた超高強度冷延鋼板およびその製造方法
JP2016153524A (ja) 2015-02-13 2016-08-25 株式会社神戸製鋼所 切断端部での耐遅れ破壊特性に優れた超高強度鋼板
WO2020129402A1 (fr) * 2018-12-21 2020-06-25 Ｊｆｅスチール株式会社 Feuille d'acier, élément, et procédé de fabrication d'une telle feuille d'acier
WO2020203158A1 (fr) * 2019-03-29 2020-10-08 日本製鉄株式会社 Tôle d'acier
WO2021045168A1 (fr) * 2019-09-03 2021-03-11 日本製鉄株式会社 Tôle d'acier
JP2021172424A (ja) 2020-04-30 2021-11-01 株式会社吉野工業所 注出容器

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006207019A (ja) 2004-12-28 2006-08-10 Kobe Steel Ltd 耐水素脆化特性及び加工性に優れた超高強度薄鋼板
JP2010138489A (ja) 2008-11-17 2010-06-24 Jfe Steel Corp 引張強さが１５００ＭＰａ以上の高強度鋼板およびその製造方法
JP2010215958A (ja) 2009-03-16 2010-09-30 Jfe Steel Corp 曲げ加工性および耐遅れ破壊特性に優れる高強度冷延鋼板およびその製造方法
JP2011179030A (ja) 2010-02-26 2011-09-15 Jfe Steel Corp 曲げ性に優れた超高強度冷延鋼板
JP2016050343A (ja) 2014-08-29 2016-04-11 新日鐵住金株式会社 耐水素脆化特性に優れた超高強度冷延鋼板およびその製造方法
JP2016153524A (ja) 2015-02-13 2016-08-25 株式会社神戸製鋼所 切断端部での耐遅れ破壊特性に優れた超高強度鋼板
WO2020129402A1 (fr) * 2018-12-21 2020-06-25 Ｊｆｅスチール株式会社 Feuille d'acier, élément, et procédé de fabrication d'une telle feuille d'acier
WO2020203158A1 (fr) * 2019-03-29 2020-10-08 日本製鉄株式会社 Tôle d'acier
WO2021045168A1 (fr) * 2019-09-03 2021-03-11 日本製鉄株式会社 Tôle d'acier
JP2021172424A (ja) 2020-04-30 2021-11-01 株式会社吉野工業所 注出容器

Also Published As

Publication number Publication date
KR20240069758A (ko) 2024-05-20
CN118140000A (zh) 2024-06-04

Similar Documents

Publication Publication Date Title
JP6409917B2 (ja) 熱延鋼板の製造方法および冷延フルハード鋼板の製造方法
US7686896B2 (en) High-strength steel sheet excellent in deep drawing characteristics and method for production thereof
US8657969B2 (en) High-strength galvanized steel sheet with excellent formability and method for manufacturing the same
JP5053157B2 (ja) プレス成形性の良好な高強度高ヤング率鋼板、溶融亜鉛めっき鋼板、合金化溶融亜鉛めっき鋼板及び鋼管、並びに、それらの製造方法
KR20190089024A (ko) 고강도 아연 도금 강판 및 그 제조 방법
JP7196997B2 (ja) 鋼板
KR101649456B1 (ko) 냉연 강판, 전기 아연계 도금 냉연 강판, 용융 아연 도금 냉연 강판, 합금화 용융 아연 도금 냉연 강판 및 그들의 제조 방법
WO2020162561A1 (fr) Tôle d'acier galvanisée par immersion à chaud et son procédé de fabrication
KR101720891B1 (ko) 합금화 용융 아연 도금 강판 및 그 제조 방법
WO2012043420A1 (fr) Tôle d'acier à haute résistance, galvanisée à chaud, se prêtant particulièrement bien à l'emboutissage profond et au bordage par étirement, et procédé de production correspondant
WO2020162560A1 (fr) Tôle d'acier galvanisée par immersion à chaud et procédé de fabrication s'y rapportant
CN113348259A (zh) 高强度热浸镀锌钢板和其制造方法
JP4407449B2 (ja) 高強度鋼板およびその製造方法
JP6409916B2 (ja) 熱延鋼板の製造方法および冷延フルハード鋼板の製造方法
WO2023068369A1 (fr) Tôle d'acier
JP6032173B2 (ja) 引張最大強度９８０ＭＰａを有する耐遅れ破壊特性に優れた高強度鋼板、高強度溶融亜鉛めっき鋼板、並びに、高強度合金化溶融亜鉛めっき鋼板
JP4506380B2 (ja) 高強度鋼板の製造方法
WO2023068368A1 (fr) Tôle d'acier
WO2023149466A1 (fr) Tôle d'acier
WO2023095870A1 (fr) Tôle d'acier galvanisée
WO2021125283A1 (fr) Tôle d'acier et son procédé de fabrication
WO2024029145A1 (fr) Tôle d'acier
CN117916398A (zh) 冷轧钢板及其制造方法以及焊接接头
KR20240023431A (ko) 냉연 강판 및 그 제조 방법

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22883671

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2023554764

Country of ref document: JP

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 20247012403

Country of ref document: KR

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 2401002448

Country of ref document: TH

WWE Wipo information: entry into national phase

Ref document number: 2022883671

Country of ref document: EP

ENP Entry into the national phase

Ref document number: 2022883671

Country of ref document: EP

Effective date: 20240521