WO2024053667A1 - Tôle d'acier et tôle d'acier plaquée - Google Patents

Tôle d'acier et tôle d'acier plaquée Download PDF

Info

Publication number
WO2024053667A1
WO2024053667A1 PCT/JP2023/032500 JP2023032500W WO2024053667A1 WO 2024053667 A1 WO2024053667 A1 WO 2024053667A1 JP 2023032500 W JP2023032500 W JP 2023032500W WO 2024053667 A1 WO2024053667 A1 WO 2024053667A1
Authority
WO
WIPO (PCT)
Prior art keywords
less
steel plate
content
steel sheet
steel
Prior art date
Application number
PCT/JP2023/032500
Other languages
English (en)
Japanese (ja)
Inventor
卓哉 光延
卓史 横山
浩史 竹林
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
Publication of WO2024053667A1 publication Critical patent/WO2024053667A1/fr

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D3/00—Diffusion processes for extraction of non-metals; Furnaces therefor
    • C21D3/02—Extraction of non-metals
    • C21D3/04—Decarburising
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • 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
    • C22C18/00—Alloys based on zinc
    • 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
    • C22C38/18—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
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/06—Zinc or cadmium or alloys based thereon

Definitions

  • the present invention relates to a steel plate and a plated steel plate. More specifically, the present invention relates to a steel plate and a plated steel plate having high LME resistance and hydrogen desorption properties.
  • LME cracking is thought to occur when the surface layer of the steel plate transforms into austenite during welding, molten zinc intrudes into the grain boundaries and embrittles the steel plate, and furthermore, tensile stress is applied to the steel plate during welding.
  • Non-Patent Document 1 it is known that ferrite phase grain boundaries have lower LME susceptibility than austenite grain boundaries with respect to LME cracking.
  • Patent Document 2 discloses that, as a steel sheet that suppresses LME cracking and improves weldability, Si oxide particles with a particle size of 20 nm or more are contained in a number density of 3000 to 6000 pieces/mm 2 in the surface layer of the steel sheet. A steel sheet having a grain size distribution is disclosed.
  • the present inventors have diligently studied means for solving the above problems. As a result, the surface layer of the steel sheet is decarburized, the ferrite ( ⁇ ) phase is stabilized, and the surface layer of the steel sheet is It has been found that the material is covered with a ferrite phase having a low solid solution amount of C, and as a result, it is possible to suppress LME. Furthermore, it has been found that by covering the surface layer of the steel sheet with a ferrite phase in which the amount of solid solution of C is low, desorption of hydrogen from the steel sheet into the atmosphere is promoted even when hydrogen enters the steel sheet.
  • the present invention has been made based on the above findings and further studies, and the gist thereof is as follows.
  • a steel plate having a tensile strength of 780 MPa or more the chemical components of which are C: 0.05 to 0.40%, Si: 0.7 to 3.0%, Mn: 0. 1-5.0%, sol. Al: 0.7-2.0%, P: 0.0300% or less, S: 0.0300% or less, N: 0.0100% or less, B: 0-0.010%, Ti: 0-0.
  • Nb 0-0.150%
  • V 0-0.150%
  • Cr 0-2.00%
  • Ni 0-2.00%
  • Cu 0-2.00%
  • Mo 0-1.00%
  • W 0-1.00%
  • Ca 0-0.100%
  • Mg 0-0.100%
  • Zr 0-0.100%
  • Hf 0-0.100 %
  • REM 0 to 0.100%, the remainder being Fe and impurities, Si and sol.
  • the total value of Al content is 1.8% or more, and the depth at which the C concentration measured by GDS is 0.05% or less in the depth direction from the steel plate surface is 10 ⁇ m or more, and A steel plate characterized in that the thickness of the layer in which the area ratio of the ferrite phase is 90% or more is 20 ⁇ m or more in the depth direction, and the steel sheet has a surface roughness Ra of 3.0 ⁇ m or less.
  • the depth at which the C concentration measured by GDS is 0.05% or less is 20 ⁇ m or more, and in the depth direction from the surface of the steel plate, a ferrite phase is formed.
  • An alloyed hot-dip galvanized layer is provided on at least a portion of the surface of the steel sheet according to any one of (1) to (4), and the plating layer contains 0 to 1.5% Al and An alloyed hot-dip galvanized steel sheet containing 3 to 15% Fe, with the remainder being Zn and impurities.
  • a steel plate and a plated steel plate having high LME resistance and hydrogen desorption properties can be obtained.
  • LME cracking occurs when the surface layer of a steel plate is heated during spot welding, the steel plate structure in the surface layer transforms into austenite, and the grain boundaries become brittle as hot-dip plating enters the steel plate structure along the austenite grain boundaries. It is caused by doing. It is thought that LME cracking occurs because tensile stress is applied to the steel plate during welding.
  • the steel sheet of the present invention improves LME resistance due to the structure formed in the surface layer. Note that in this specification, the surface layer of a steel plate refers to the range from the outermost surface of the steel plate to a depth of 100 ⁇ m.
  • the C element is contained in the surface layer of a steel sheet, LME cracking is likely to occur, so keeping the C concentration in the surface layer of the steel sheet low is effective in preventing LME cracking.
  • the C concentration in the surface layer of the steel sheet is difficult to decrease.
  • the steel plate of the present invention in the depth direction from the steel plate surface, there is a region 10 ⁇ m or more from the steel plate surface where the C concentration measured by GDS is 0.05% or less. This means that the concentration of C, which is an element that tends to cause LME, is low in the surface layer of the steel sheet.
  • the thickness of the region where the area ratio of the ferrite phase is 90% or more in the depth direction from the steel plate surface is 20 ⁇ m or more.
  • the steel sheet of the present invention contains a large amount of Si, which is conventionally known to reduce LME resistance when contained in steel. As a result of the studies conducted by the present inventors, contrary to the conventional knowledge, Si and sol. This is because it has been found that LME resistance is improved by containing a large amount of Al in a steel plate.
  • a strong strain is applied to the surface layer of the steel plate without increasing the surface roughness, and the steel plate is annealed at a high dew point.
  • This allows oxygen to diffuse into the steel sheet and form internal oxides, making it possible to suppress the formation of external oxides.
  • the C concentration in the surface layer of the steel sheet is reduced, and Si and sol. This is thought to be due to the fact that the ferrite can be stabilized by the effect of the combined addition of Al.
  • the steel plate of the present invention contains Si and sol. Due to the combined effect of high Al content, applying strain to the surface layer before annealing, and controlling the dew point during annealing, a layer with a low C concentration and a high area ratio of ferrite is formed on the surface layer of the steel sheet. This makes it possible to improve LME resistance.
  • % regarding chemical components means “% by mass”.
  • a numerical range expressed using “ ⁇ ” means a range that includes the numerical values written before and after " ⁇ " as lower and upper limits.
  • C 0.05-0.40%
  • C (carbon) is an element that ensures the strength of steel.
  • the C content is set to 0.05 MPa in consideration of the balance with weldability and to prevent the C concentration in the surface layer of the steel sheet from becoming too high. ⁇ 0.40%. If the C content is too large, the C concentration in the surface layer will not be reduced even by high dew point annealing, which will be described later, and the ferrite fraction will not be high.
  • the content of C may be 0.07% or more, 0.10% or more, or 0.12% or more.
  • the content of C may be 0.35% or less, 0.30% or less, or 0.25% or less.
  • Si Si: 0.7-3.0%, sol.Al: 0.7-2.0%, Si+sol.Al ⁇ 1.8%)
  • Si silicon
  • Al aluminum
  • Si and sol. The total value of Al content is 1.8% or more. Si and sol. This is because when the Al content satisfies such a numerical range, decarburization of the surface layer of the steel sheet can be promoted and ferrite in the surface layer can be stabilized in the heat treatment of the manufacturing process of the steel sheet of this embodiment. sol.
  • Al refers to acid-soluble Al that is not converted into oxides such as Al 2 O 3 and is soluble in acids, and was measured by subtracting the insoluble residue on the filter paper that is generated during the Al analysis process.
  • the content of Si may be 0.8% or more, 0.9% or more, or 1.0% or more.
  • the content of Si may be 2.8% or less, 2.5% or less, or 2.0% or less.
  • the Al content may be 0.8% or more, 0.9% or more, or 1.0% or more. sol.
  • the Al content may be 1.8% or less, 1.6% or less, or 1.5% or less.
  • the total content of Al may be 1.9% or more, or 2.0% or more.
  • Mn manganese
  • Mn manganese
  • Mn content is set to 0.1 to 5.0%.
  • the Mn content may be 0.5% or more, 1.0% or more, or 1.5% or more.
  • the Mn content may be 4.5% or less, 4.0% or less, or 3.5% or less.
  • P 0.0300% or less
  • P phosphorus
  • the content of P may be 0.0200% or less, 0.0100% or less, or 0.0050% or less. It is preferable that P is not contained, and the lower limit of the P content is 0%. From the viewpoint of dephosphorization cost, the P content may be more than 0%, 0.0001% or more, or 0.0005% or more.
  • S sulfur
  • S is an impurity generally contained in steel. If the S content exceeds 0.0300%, weldability will decrease, and furthermore, the amount of MnS precipitated may increase, leading to a possibility that workability such as bendability will decrease. Therefore, the S content is set to 0.0300% or less.
  • the S content may be 0.0100% or less, 0.0050% or less, 0.0030% or less, 0.0020% or less, or 0.0010% or less. It is preferable that S is not contained, and the lower limit of the S content is 0%. From the viewpoint of desulfurization cost, the S content may be more than 0%, 0.0001% or more, or 0.0005% or more.
  • N nitrogen
  • nitrogen is an impurity generally contained in steel. If the N content exceeds 0.0100%, weldability may deteriorate. Therefore, the N content is set to 0.0100% or less.
  • the content of N may be 0.0080% or less, 0.0050% or less, 0.0030% or less, 0.0020% or less, or 0.0010% or less. It is preferable that N is not contained, and the lower limit of the N content is 0%. From the viewpoint of manufacturing cost, the N content may be more than 0%, 0.0001% or more, 0.0002% or more, 0.0003% or more, or 0.0005% or more.
  • B (boron) is an element that increases hardenability and contributes to improvement of strength, and also segregates at grain boundaries to strengthen grain boundaries and improve toughness, so it may be included as necessary. . Since B is not an essential element, the lower limit of the content of B is 0%. Although this effect can be obtained even when B is contained in a trace amount, it is preferable that the content of B is 0.0001% or more.
  • the content of B may be 0.0002% or more, 0.0003% or more, 0.0005% or more, 0.0007% or more, or 0.0010% or more.
  • the B content is set to 0.010% or less.
  • the content of B may be 0.0080% or less, 0.0060% or less, 0.0050% or less, 0.0040% or less, or 0.0030% or less.
  • Ti titanium
  • Ti titanium
  • Ti titanium
  • the lower limit of the content of Ti is 0%.
  • the content of Ti is preferably 0.0001% or more.
  • the content of Ti may be 0.0002% or more, 0.0003% or more, 0.0005% or more, 0.0007% or more, or 0.0010% or more.
  • coarse TiN may be generated and toughness may be impaired, so the content of Ti is set to 0.150% or less.
  • the Ti content is 0.1000% or less, 0.0500% or less, 0.0300% or less, 0.0200% or less, 0.0100% or less, 0.0050% or less, or 0.0030% or less. good.
  • Nb 0-0.150% Since Nb (niobium) is an element that contributes to improving strength through improving hardenability, it may be included as necessary. Since Nb is not an essential element, the lower limit of the content of Nb is 0%. Although this effect can be obtained even with a trace amount of Nb, the content of Nb is preferably 0.001% or more. The Nb content may be 0.002% or more, 0.003% or more, 0.005% or more, or 0.008% or more. On the other hand, from the viewpoint of ensuring sufficient toughness, the Nb content is set to 0.150% or less. The Nb content may be 0.100% or less, 0.060% or less, 0.050% or less, 0.040% or less, or 0.030% or less.
  • V vanadium
  • V vanadium
  • the lower limit of the content of V is 0%.
  • the content of V is set to 0.150% or less.
  • the V content may be 0.100% or less, 0.060% or less, 0.050% or less, 0.040% or less, or 0.030% or less.
  • Cr 0-2.00% Cr (chromium) is effective in improving the hardenability of steel and increasing the strength of steel, and therefore may be contained as necessary. Since Cr is not an essential element, the lower limit of the content of Cr is 0%. Although this effect can be obtained even with a trace amount of Cr, the content of Cr is preferably 0.001% or more.
  • the content of Cr may be 0.01% or more, 0.02% or more, 0.03% or more, 0.05% or more, or 0.08% or more.
  • the content of Cr is set to 2.00% or less.
  • the content of Cr may be 1.80% or less, 1.50% or less, 1.20% or less, 1.00% or less, 0.70% or less, 0.50% or less, or 0.30% or less. .
  • Ni nickel
  • Ni nickel
  • the lower limit of the Ni content is 0%.
  • the Ni content may be 0.01% or more, 0.02% or more, 0.03% or more, 0.05% or more, or 0.07% or more.
  • the Ni content is set to 2.00% or less.
  • the Ni content is 1.80% or less, 1.50% or less, 1.20% or less, 1.00% or less, 0.80% or less, 0.50% or less, 0.30% or less, or 0. It may be 20% or less.
  • Cu (Cu: 0-2.00%) Cu (copper) is effective in improving the hardenability of steel and increasing the strength of steel, and therefore may be contained as necessary. Since Cu is not an essential element, the lower limit of the content of Cu is 0%. Although this effect can be obtained even with a trace amount of Cu, the content of Cu is preferably 0.0001% or more. The content of Cu may be 0.0002% or more, 0.0003% or more, or 0.0005% or more. On the other hand, from the viewpoint of suppressing a decrease in toughness and cracking of the slab after casting, the content of Cu is set to 2.00% or less.
  • the Cu content is 1.8000% or less, 1.5000% or less, 1.2000% or less, 1.0000% or less, 0.5000% or less, 0.1000% or less, 0.0500% or less, 0.0100 % or less, 0.0050% or less, 0.0030% or less, or 0.0020% or less.
  • Mo mobdenum
  • Mo mobdenum
  • the lower limit of the content of Mo is 0%.
  • the content of Mo is preferably 0.001% or more.
  • the Mo content may be 0.01% or more, 0.02% or more, 0.03% or more, 0.05% or more, or 0.08% or more.
  • the Mo content is set to 1.00% or less.
  • the Mo content may be 0.90% or less, 0.70% or less, 0.50% or less, or 0.30% or less.
  • W 0-1.00% W (tungsten) is effective in improving the hardenability of steel and increasing the strength of steel, and therefore may be included as necessary. Since W is not an essential element, the lower limit of the content of W is 0%. Although this effect can be obtained even when a small amount of W is included, it is preferable that the content of W is 0.001% or more. The content of W may be 0.002% or more, 0.003% or more, or 0.004% or more. On the other hand, from the viewpoint of suppressing a decrease in toughness, the W content is set to 1.00% or less. The content of W is 0.900% or less, 0.700% or less, 0.500% or less, 0.300% or less, 0.100% or less, 0.050% or less, 0.030% or less, or 0. It may be 0.020% or less.
  • Ca (Ca: 0-0.100%)
  • Ca (calcium) is an element that contributes to control of inclusions, particularly fine dispersion of inclusions, and has the effect of increasing toughness, and therefore may be contained as necessary. Since Ca is not an essential element, the lower limit of the content of Ca is 0%. Although this effect can be obtained even with a trace amount of Ca, the content of Ca is preferably 0.0001% or more.
  • the Ca content may be 0.0002% or more, 0.0003% or more, or 0.0004% or more.
  • the Ca content is set to 0.100% or less.
  • the Ca content is 0.0800% or less, 0.0500% or less, 0.0100% or less, 0.0050% or less, 0.0030% or less, 0.0020% or less, or 0.0010% or less. good.
  • Mg manganesium
  • Mg is an element that contributes to control of inclusions, particularly to fine dispersion of inclusions, and has the effect of increasing toughness, and therefore may be contained as necessary. Since Mg is not an essential element, the lower limit of the Mg content is 0%. Although this effect can be obtained even with a trace amount of Mg, it is preferable that the Mg content is 0.0001% or more.
  • the content of Mg may be 0.0002% or more, 0.0003% or more, 0.0005% or more, or 0.0008% or more.
  • the content of Mg is set to 0.100% or less.
  • the Mg content may be 0.090% or less, 0.080% or less, 0.050% or less, 0.010% or less, 0.005% or less, or 0.003% or less.
  • Zr zirconium
  • Zr zirconium
  • Zr zirconium
  • Zr zirconium
  • the content of Zr may be 0.002% or more, 0.003% or more, 0.005% or more, or 0.010% or more.
  • the Zr content is set to 0.100% or less.
  • the content of Zr may be 0.080% or less, 0.050% or less, 0.040% or less, or 0.030% or less.
  • Hf (hafnium) is an element that contributes to inclusion control, particularly fine dispersion of inclusions, and has the effect of increasing toughness, and therefore may be contained as necessary. Since it is not an essential element, the lower limit of the content of Hf is 0%. Although this effect can be obtained even with a trace amount of Hf, it is preferable that the Hf content is 0.0001% or more. The Hf content may be 0.0002% or more, 0.0003% or more, 0.0005% or more, or 0.0008% or more. On the other hand, since excessive Hf content may cause deterioration of surface properties, the content of Hf is set to 0.100% or less. The content of Hf is 0.050% or less, 0.030% or less, 0.010% or less, 0.005% or less, or 0.003% or less.
  • REM 0-0.100%
  • REM rare earth element
  • the lower limit of the content of REM is 0%.
  • the content of REM is preferably 0.0001% or more.
  • the content of REM may be 0.0003% or more, 0.0005% or more, or 0.0007% or more.
  • the content of REM is set to 0.100% or less.
  • the content of REM may be 0.0500% or less, 0.0300% or less, 0.0100% or less, 0.0050% or less, 0.0030% or less, or 0.0020% or less.
  • REM is an abbreviation for Rare Earth Metal, and refers to an element belonging to the lanthanide series. REM is usually added as a misch metal.
  • the remainder other than the above chemical components consists of Fe and impurities.
  • impurities are components that are mixed in due to various factors in the manufacturing process, including raw materials such as ore and scrap, when steel sheets are industrially manufactured. It means a substance that is contained within a range that does not adversely affect LME properties and hydrogen desorption properties, that is, it can provide the LME resistance and hydrogen desorption properties required for the steel sheet of the present invention.
  • the chemical components of the steel plate may be analyzed using elemental analysis methods known to those skilled in the art, such as inductively coupled plasma mass spectrometry (ICP-MS).
  • ICP-MS inductively coupled plasma mass spectrometry
  • C and S may be measured using the combustion-infrared absorption method
  • N may be measured using the inert gas melting-thermal conductivity method.
  • the depth at which the C concentration measured by GDS (glow discharge spectroscopy) is 0.05% or less is 10 ⁇ m or more in the depth direction from the steel plate surface.
  • LME resistance improves when the C concentration in the surface layer is low. Further, since C is an austenite stabilizing element, a small amount of C stabilizes the ferrite phase with low LME sensitivity, which will be described later. Furthermore, when there is less C in the surface layer, hydrogen that has entered the steel easily escapes, improving hydrogen desorption performance. This is presumed to be because the presence of less C, which is an interstitial element, in the ferrite phase makes it easier for hydrogen to pass through.
  • Such a surface structure can be obtained by changing the chemical composition of the steel sheet to a component containing a large amount of Si and Al, as described above, and by heat treatment described below.
  • the depth at which the C concentration is 0.05% or less is 10 ⁇ m or more, the effect of improving LME resistance can be obtained, so the upper limit of the depth is not particularly limited. For example, it may be 50 ⁇ m or less, 40 ⁇ m or less, or 30 ⁇ m or less.
  • the depth at which the C concentration is 0.05% or less is preferably 20 ⁇ m or more.
  • the GDS measurement is performed five times in the thickness direction, and the average value of these measurements is taken as the C concentration.
  • the measurement conditions are as follows.
  • the starting point of "depth” is the surface of the steel plate for an unplated steel plate, and the interface between the steel plate and the plating layer for a plated steel plate.
  • the interface between the steel plate and the plating layer is located at a position where the Fe concentration measured by GDS measurement is 93% of the Fe concentration at a depth of 150 ⁇ m.
  • the thickness of the layer in which the area ratio of the ferrite phase is 90% or more is 20 ⁇ m or more in the depth direction from the steel sheet surface.
  • FIG. 1 shows an example of a microstructure photograph taken by SEM near the surface layer of the steel sheet of the present invention.
  • FIG. 1 is a cross section of a steel plate in the thickness direction, and the upper side of the drawing is the surface of the steel plate.
  • the surface layer of the steel sheet in FIG. 1 has a low C concentration and includes a layer with a ferrite phase area ratio of 90% or more.
  • the inside of the steel plate has a structure mainly composed of martensite and containing ferrite.
  • a layer having a ferrite phase area ratio of 90% or more exists in the surface layer with a thickness of 40 ⁇ m.
  • Non-Patent Document 1 It is known that ferrite phase grain boundaries have lower LME susceptibility than ⁇ (austenite) grain boundaries (for example, Non-Patent Document 1). Therefore, by having a thick structure mainly composed of ferrite phase in the surface layer of the steel sheet, LME is less likely to occur even when the plating melts, and LME resistance can be improved.
  • Such a surface structure can be obtained by changing the chemical composition of the steel sheet to a component containing a large amount of Si and Al, as described above, and by heat treatment described below.
  • the thickness of the region where the area ratio of the ferrite phase is 90% or more is 20 ⁇ m or more, the effect of improving LME resistance can be obtained, so the upper limit of the thickness is not particularly limited. For example, it may be 100 ⁇ m or less, 80 ⁇ m or less, or 60 ⁇ m or less.
  • the thickness of the region where the area ratio of the ferrite phase is 90% or more is preferably 30 ⁇ m or more.
  • the thickness of the region where the area ratio of the ferrite phase is 90% or more can be determined by nital etching the L cross section of the steel plate and observing it with SEM. Martensite, bainite, and ferrite can be distinguished from the structure morphology. Specifically, the cross section in the L direction is polished, and after mirror polishing, nital etching is used to expose the steel structure by corrosion. Thereafter, secondary electron images of five fields of view are photographed at equal intervals at a magnification of 1500 times in a range of 500 ⁇ m in the depth direction based on the steel surface. The area ratio of the ferrite phase is measured by a point counting method (based on ASTM E562), and the thickness of a region where the area ratio of the ferrite phase is 90% or more is measured for each photographic field of view.
  • the area ratio of the ferrite phase refers to the area ratio determined by observing the L cross section. Even if there is a local part in the thickness direction where the area ratio of the ferrite phase is less than 90% when observing the C section, the area of the ferrite phase in the L section up to a depth of 20 ⁇ m If the rate is 90% or higher, there is no problem. More specific area ratios are as follows.
  • the ferrite area ratio is measured as follows.
  • the steel plate is cut along an imaginary line on the surface of the steel plate perpendicular to the rolling direction of the steel plate, in the thickness direction, that is, perpendicular to the surface of the steel plate, and a test piece is cut out.
  • the cross section of the steel plate perpendicular to the rolling direction is polished to a mirror surface, the steel structure is exposed using a nital solution, and a secondary electron image is taken using a field emission scanning electron microscope.
  • the field of view to be observed is from the surface of the steel sheet in the case of a non-plated steel sheet, and from the interface between the steel sheet and the plating layer in the case of a plated steel sheet to a depth of 500 ⁇ m, and five fields of view are observed at equal intervals.
  • the fraction of each tissue is calculated by the point counting method. First, draw an equally spaced grid on the tissue photograph. Next, it is determined whether the structure at each lattice point corresponds to tempered martensite, pearlite, ferrite, fresh martensite, retained austenite, or bainite. By finding the number of lattice points corresponding to each tissue and dividing by the total number of lattice points, the fraction of each tissue can be measured.
  • the grid spacing is 2 ⁇ m ⁇ 2 ⁇ m
  • the total number of grid points is 1500 points.
  • the criteria for determining pearlite, ferrite, martensite, and bainite are as follows. A region that has a substructure (lath boundary, block boundary) within the grain and in which carbides are precipitated in a plurality of variants is determined to be tempered martensite. In addition, a region where cementite is precipitated in a lamellar shape is determined to be pearlite. A region with low brightness and no underlying structure is determined to be ferrite. A region where the brightness is high and the underlying structure is not exposed by etching is determined to be fresh martensite or retained austenite. Areas that do not fall under any of the above are determined to be bainite. Simply speaking, the area ratio of the ferrite phase can be determined by distinguishing between ferrite and other structures.
  • the steel plate of the present invention has a surface roughness of 3.0 ⁇ m or less in arithmetic mean height Ra defined by JIS B0601:2013. When the roughness increases, cracks are more likely to occur due to stress concentration, resulting in a decrease in LME resistance.
  • the surface roughness may be 2.5 ⁇ m or less, or 2.0 ⁇ m or less.
  • the steel plate according to the present invention has high strength. Specifically, it has a tensile strength of 780 MPa or more.
  • the upper limit of the tensile strength is not particularly limited, but from the viewpoint of ensuring toughness, it may be, for example, 2000 MPa or less.
  • the tensile strength may be measured in accordance with JIS Z 2241:2011 by taking a JIS No. 5 tensile test piece whose longitudinal direction is perpendicular to the rolling direction.
  • the tensile strength may be 880 MPa or more, 980 MPa or more, 1080 MPa or more, or 1180 MPa or more.
  • the tensile strength may be 1900 MPa or less, or 1800 MPa or less.
  • the plated steel sheet according to the present invention has an alloyed hot-dip galvanized layer on the above-described steel sheet according to the present invention.
  • the plating layer is formed on at least a portion of the surface of the steel plate, and may be formed on one side or both sides of the steel plate.
  • Al is an element that improves the corrosion resistance of the plating layer by being included or alloyed with Zn, it may be included as necessary. Therefore, the Al content may be 0%.
  • the Al content is preferably 0.01% or more, and may be 0.1% or more.
  • the content of Al in the plating layer is preferably 0.3 to 1.5%.
  • Fe is contained in the plating layer by being diffused from the steel sheet when the plated steel sheet is heat treated after forming a plating layer containing Zn on the steel sheet.
  • the Fe content may be 3.0% or more, and may be 4.0% or more or 5.0% or more.
  • the Fe content may be 15.0% or less, for example, 12.0% or less, 10.0% or less, 8.0% or less, or 6.0% or less.
  • the remainder of the plating layer other than the above components consists of Zn and impurities.
  • Impurities in the plating layer are components that are mixed into the plating layer due to various factors in the manufacturing process, including raw materials, and are not intentionally added to the plating layer. do.
  • trace amounts of elements other than the basic components and optionally added components described above may be included as impurities within a range that does not impede the effects of the present invention.
  • the chemical composition of the plating layer can be determined by dissolving the plating layer in an acid solution containing an inhibitor that suppresses corrosion of the steel sheet, and measuring the resulting solution by ICP (inductively coupled plasma) emission spectroscopy.
  • the acid solution containing an inhibitor may be, for example, a 10% by mass hydrochloric acid solution containing 0.06% by mass of an inhibitor (manufactured by Asahi Chemical Co., Ltd., Ivit).
  • the thickness of the plating layer may be, for example, 3 to 50 ⁇ m. Further, the amount of the plating layer deposited is not particularly limited, but may be, for example, 10 to 170 g/m 2 per side. In the present invention, the amount of the plating layer deposited is determined by dissolving the plating layer in an acid solution containing an inhibitor that suppresses corrosion of the steel plate, and from the change in weight of the plating layer before and after pickling and stripping. The thickness of the plating layer may be 5 ⁇ m or more, 10 ⁇ m or more, 15 ⁇ m or more, or 20 ⁇ m or more. The thickness of the plating layer may be 40 ⁇ m or less, or 30 ⁇ m or less.
  • the amount of the plating layer deposited on one side may be 20 g/m 2 or more, 30 g/m 2 or more, 40 g/m 2 or more, or 50 g/m 2 or more.
  • the amount of the plating layer deposited per side may be 150 g/m 2 or less, 130 g/m 2 or less, 120 g/m 2 or less, or 100 g/m 2 or less.
  • the roughness of the interface between the steel plate and the plating layer corresponds to the roughness of the surface of the steel plate described above, so Ra is 3.0 ⁇ m or less. Considering the adhesion of plating, Ra may be 2.5 ⁇ m or less, or 2.0 ⁇ m or less. It may be the roughness of the interface between the steel plate and the plating layer, or the surface roughness of the steel plate measured by dissolving and removing the plating.
  • the steel sheet of the present invention has the effect of improving LME resistance even if it is not galvanized.
  • LME cracking does not occur when ungalvanized steel plates are welded together.
  • molten galvanization occurs on the overlapping surfaces of the steel plates during welding. Therefore, there is a possibility that LME cracking may occur due to contact with the surface of the steel sheet that is not subjected to molten galvanization.
  • the zinc plating attached to the welding electrode melts and comes into contact with the surface of the steel plate, resulting in LME cracking.
  • the steel sheet of the present invention is used as an unplated steel sheet, even in such a case, LME cracking can be suppressed even in the welding process because the C concentration in the surface layer is low and the surface layer is a ferrite phase. Can be done.
  • the thickness of the steel plate and plated steel plate of the present invention is not particularly limited. For example, it can be 0.6 to 3.2 mm.
  • the plate thickness may be 0.8 mm or more, or 1.0 mm or more.
  • the plate thickness may be 3.0 mm or less, 2.6 mm or less, 2.4 mm or less, 2.2 mm or less, 2.0 mm or less, or 1.8 mm or less.
  • the steel plate according to the present invention can be produced, for example, by a casting process in which molten steel with adjusted chemical components is cast to form a steel billet, a hot rolling process in which a hot rolled steel plate is obtained by hot rolling a steel billet, and a hot rolling process in which a hot rolled steel plate is wound.
  • the conditions of the casting process are not particularly limited. For example, following melting in a blast furnace, electric furnace, etc., various secondary smelting may be performed, and then casting may be performed by a method such as ordinary continuous casting or ingot casting.
  • a hot rolled steel plate can be obtained by hot rolling a steel piece obtained by casting.
  • the hot rolling process is performed by directly or once cooling the cast steel billet, then reheating and hot rolling.
  • the heating temperature of the steel piece may be, for example, 1100 to 1250°C.
  • rough rolling and finish rolling are usually performed.
  • the temperature and reduction rate of each rolling may be changed as appropriate depending on the desired metal structure and plate thickness.
  • the end temperature of finish rolling may be 900 to 1050°C, and the reduction ratio of finish rolling may be 10 to 50%.
  • Hot-rolled steel sheets can be rolled up at a predetermined temperature.
  • the winding temperature may be changed as appropriate depending on the desired metal structure, etc., and may be, for example, 500 to 800°C.
  • the hot-rolled steel sheet may be subjected to a predetermined heat treatment by unwinding the hot-rolled steel sheet before or after winding.
  • the hot rolled steel sheet After pickling or the like is performed on the hot rolled steel sheet, the hot rolled steel sheet can be cold rolled to obtain a cold rolled steel sheet.
  • the rolling reduction ratio of cold rolling may be changed as appropriate depending on the desired metallographic structure and plate thickness, and may be, for example, 20 to 80%.
  • the material After the cold rolling process, the material may be cooled to room temperature by, for example, air cooling.
  • the thickness of the layer in which the area ratio of the ferrite phase is 90% or more in the depth direction is 20 ⁇ m or more, and the C concentration in the depth direction is 0.05% as measured by GDS.
  • the C concentration in the depth direction is 0.05% as measured by GDS.
  • the pretreatment includes grinding the surface of the cold rolled steel plate with a grinding brush (brush grinding process).
  • a grinding brush that can be used is M-33 manufactured by Hotani Corporation. Thereby, strain can be introduced without increasing the surface roughness.
  • it is recommended to apply a 1.0 to 5.0% NaOH aqueous solution to the surface of the steel plate.
  • the brush reduction amount is 0.5 to 10.0 mm and the rotation speed is 100 to 1000 rpm.
  • the cold rolled steel sheet is annealed.
  • Annealing is performed under a tension of 1 to 20 MPa, for example. Applying tension during annealing makes it possible to more effectively introduce strain into the steel sheet, promoting decarburization of the surface layer.
  • the holding temperature in the annealing step is 750 to 900°C.
  • the holding temperature may be 770-870°C. By setting it within such a range, decarburization can be promoted, the C concentration in the surface layer can be reduced, and the ferrite phase can be stabilized.
  • the heating rate up to the holding temperature is not particularly limited, but may be 1 to 10° C./sec.
  • the holding time at the holding temperature in the annealing step is 20 to 300 seconds.
  • the holding time may be between 30 and 250 seconds.
  • the atmosphere in the annealing step has a dew point of -30 to 20°C.
  • the dew point may be -10 to 5°C.
  • the atmosphere may be, for example, N 2 -1 to 10 vol% H 2 or N 2 -2 to 4 vol% H 2 . If the dew point is too high or too low, a phase containing oxides such as Si, Mn, and Al will be formed outside the steel sheet, and decarburization will not be promoted. Furthermore, mutual diffusion of plating components and steel components may be inhibited, resulting in insufficient plating properties.
  • the plated steel sheet according to the present invention can be obtained by a plating process and an alloying process in which an alloyed hot-dip galvanized layer is formed on a steel plate manufactured as described above.
  • the plating process and the alloying process may be performed according to hot-dip plating methods and alloying processes known to those skilled in the art.
  • the conditions for the plating process and the alloying process may be appropriately set in consideration of the desired chemical composition, thickness, adhesion amount, etc. of the plating layer. For example, it may be immersed in a hot-dip galvanizing bath at 420 to 480° C. with adjusted chemical components for 1 to 10 seconds, and then pulled out at 20 to 200 mm/sec after immersion, and the amount of plating deposited may be controlled by N 2 wiping gas.
  • the alloying treatment may be performed, for example, at 500 to 550° C. for 10 to 60 seconds.
  • the steel sheets and plated steel sheets according to the present invention have high strength, high LME resistance and hydrogen desorption properties, and therefore can be suitably used in a wide range of fields such as automobiles, home appliances, and building materials. It is particularly preferred to be used in the automotive field. Steel plates and plated steel plates used for automobiles are often spot welded, and in this case, LME cracking can become a significant problem. Therefore, when the steel sheet and plated steel sheet according to the present invention are used as steel sheets for automobiles, the effect of the present invention of having high LME resistance is suitably exhibited.
  • Example A First, preliminary experiments conducted by the inventors in obtaining the present invention will be described. Spot welding was performed on steel plates (1.2 mm thick) with varying Si and Al contents to a general alloyed hot-dip galvanized steel plate (1.6 mm thick) under the conditions shown in Table 1. Internal cracking in the LME was confirmed. Table 2 shows the results. As shown in Table 2, it was confirmed that LME was suppressed in the high Si-high Al steel.
  • Example B ⁇ Example 1> (Preparation of steel plate sample) No. of Table 3 Molten steel adjusted to have the chemical composition described in 1 was melted in a blast furnace and cast by continuous casting to obtain a steel billet. The obtained steel piece was heated to 1200°C and hot rolled at a finish rolling end temperature of 950°C and a finish rolling reduction of 30% to obtain a hot rolled steel plate. The obtained hot-rolled steel sheet was wound up at a winding temperature of 650° C., pickled, and then cold-rolled at a rolling reduction of 50% to obtain a cold-rolled steel sheet. The thickness of the cold-rolled steel plate was 1.6 mm.
  • the surface roughness of the steel plate was measured in accordance with JIS B 0601:2013. That is, 10 locations are randomly selected on the surface of the surface layer side, the surface profile at each location is measured using a contact type surface roughness meter, and the arithmetic mean roughness Ra is obtained by arithmetic averaging of the surface roughness at those locations. , was evaluated as follows.
  • Evaluation AA 2.0 ⁇ m or less Evaluation A: More than 2.0 ⁇ m, 3.0 ⁇ m or less Evaluation B: More than 3.0 ⁇ m
  • annealing was performed in a N 2 -4% H 2 gas atmosphere in a furnace with an oxygen concentration of 20 ppm or less at a dew point of 0° C., a holding temperature of 800° C., and a holding time of 100 seconds to prepare a steel plate sample.
  • the temperature increase rate during annealing was 6.0°C/sec up to 500°C, and 2.0°C/sec from 500°C to the holding temperature.
  • the annealing treatment was performed under a tension of 15 MPa.
  • Examples 2 to 25 Comparative Examples 26 to 40> A steel plate was produced in the same manner as in Example 1, except that the chemical components were as shown in Table 3, and the conditions for the pretreatment step and annealing step were as shown in Table 4. In addition, No. In No. 39, the pretreatment of brush grinding was omitted. Also, No. In No. 40, a grinding brush D-100 manufactured by Hotani Co., Ltd. was used (condition B in Table 4). D-100 is a brush with approximately twice the amount of grinding as M-33.
  • the steel sheets whose "Presence or absence of alloyed hot-dip galvanized layer" in Table 5 was "present” were subjected to plating treatment and alloying treatment to obtain alloyed hot-dip galvanized steel sheets.
  • the plating treatment was performed by immersing the sample in a hot-dip galvanizing bath (Zn-0.14% Al) at 450°C for 3 seconds. After dipping, it was pulled out at 100 mm/sec, and the amount of plating deposited was controlled to 50 g/m 2 using N 2 wiping gas. Alloying treatment was performed at 520°C for 30 seconds. Steel plates with "no alloyed galvanized layer" in Table 5 were not subjected to plating or alloying.
  • the surface of the steel plate for unplated steel sheets, and the plating for plated steel sheets were treated using a 10 mass% hydrochloric acid solution containing 0.06 mass% inhibitor (manufactured by Asahi Chemical Co., Ltd., Ivit).
  • the surface roughness of the removed and exposed steel plate was measured in the same manner as before annealing, and is shown in "Steel plate surface or steel plate/plating interface roughness" in Table 5.
  • Evaluation AAA 1180MPa or more Evaluation AA: 980MPa or more, less than 1180MPa Evaluation A: 780MPa or more, less than 980MPa
  • the LME resistance was evaluated as follows by superimposing two steel plates 1 and performing spot welding, and based on the length of the crack 11 just outside the pressure welded part of the welded part 2.
  • the term "directly outside the press-welded part of the welded part” refers to a position outside the press-welded part by spot welding on the mating surfaces of two steel plates, and in the vicinity of the press-welded part. In this example, if the evaluation was A or higher, it was determined that the LME resistance was excellent.
  • Evaluation AAA 0 ⁇ m Evaluation AA: More than 0 ⁇ m and less than 60 ⁇ m Evaluation A: More than 60 ⁇ m and less than 120 ⁇ m Evaluation B: More than 120 ⁇ m
  • Hydrogen desorption test A test piece having a size of 80 mm x 50 mm was cut out from each steel plate and electrochemically charged with hydrogen. Electricity was applied for 48 hours under constant current control (cathode current density 1 mA/cm 2 ) in a 3% NaCl+3 g/L NH 4 SCN aqueous solution. After hydrogen charging, the plated steel plate was left standing in the air at room temperature for 48 hours, and after a predetermined period of time, the amount of diffusible hydrogen contained in the plated steel plate was measured using the temperature-programmed desorption method, and the amount of diffusible hydrogen contained in the plated steel plate was measured as follows. evaluated.
  • the temperature programmed desorption method the temperature was raised to 400°C at a heating rate of 100°C/h, and the total amount of hydrogen released from room temperature to 200°C was defined as the amount of diffusible hydrogen.
  • the evaluation was A or higher, it was determined that the hydrogen desorption property was excellent.
  • both LME resistance and hydrogen desorption performance were excellent it was determined that the problem to be solved by the present invention was solved.
  • Evaluation AAA 10% or less of the initial hydrogen amount Evaluation AA: 20% or less of the initial hydrogen amount Evaluation A: Less than 50% of the initial hydrogen amount Evaluation B: 50% or more of the initial hydrogen amount
  • No. No. 26 is a comparative example in which the steel plate has a high C content. It is thought that because the steel sheet has a high C content, decarburization in the surface layer did not proceed even with high dew point annealing. Therefore, the depth where the C concentration is 0.05% or less and the thickness of the layer where the area ratio of the ferrite phase is 90% or more were not large. As a result, the LME resistance and hydrogen desorption properties were poor.
  • No. No. 27 is a comparative example in which the steel plate has a low Si content. It is thought that because the Si content of the steel sheet was low, decarburization did not progress in the surface layer even if high dew point annealing was performed, and ferrite was not stabilized. Therefore, the depth where the C concentration is 0.05% or less and the thickness of the layer where the area ratio of the ferrite phase is 90% or more were not large. As a result, the LME resistance and hydrogen desorption properties were poor.
  • No. 28 is the Si content of the steel plate, and the Si and sol.
  • This is a comparative example in which the sum of Al contents is small. Si content of steel plate and Si and sol. It is thought that because the sum of the Al contents was small, decarburization did not proceed in the surface layer even if high dew point annealing was performed, and the ferrite was not stabilized. Therefore, the depth where the C concentration is 0.05% or less and the thickness of the layer where the area ratio of the ferrite phase is 90% or more were not large. As a result, the LME resistance and hydrogen desorption properties were poor.
  • No. No. 29 is a comparative example in which the steel plate has a high Si content. It is thought that because the Si content of the steel sheet was high, even if high dew point annealing was performed, external oxidation progressed and oxides (scale) were formed on the surface layer of the steel sheet, suppressing decarburization at the outermost surface. Therefore, the depth at which the C concentration was 0.05% or less was not large. As a result, the LME resistance and hydrogen desorption properties were poor.
  • No. 30 is the steel plate sol. This is a comparative example with a low Al content. Steel plate sol. It is thought that because the Al content was low, decarburization did not proceed in the surface layer even though high dew point annealing was performed, and the ferrite was not stabilized. Therefore, the depth where the C concentration is 0.05% or less and the thickness of the layer where the area ratio of the ferrite phase is 90% or more were not large. As a result, the LME resistance and hydrogen desorption properties were poor.
  • No. 31 is the steel plate sol. Al content, Si and sol. This is a comparative example in which the sum of the Al contents is small. Steel plate sol. Al content and sol. It is considered that because the sum of the Al contents was small, decarburization did not progress in the surface layer even if high dew point annealing was performed, and the ferrite was not stabilized. Therefore, the depth where the C concentration is 0.05% or less and the thickness of the layer where the area ratio of the ferrite phase is 90% or more were not large. As a result, the LME resistance and hydrogen desorption properties were poor.
  • No. 32 is the steel plate sol. This is a comparative example with a high content of Al. Steel plate sol. It is thought that because the Al content was high, even if high dew point annealing was performed, external oxidation progressed and oxides (scale) were formed on the surface layer of the steel sheet, suppressing decarburization at the outermost surface. Therefore, the depth at which the C concentration was 0.05% or less was not large. As a result, the LME resistance and hydrogen desorption properties were poor.
  • No. 33 is Si and sol. This is a comparative example in which the sum of the Al contents is small. Si and sol. of steel plate. It is thought that because the sum of the Al contents was small, decarburization did not proceed in the surface layer even if high dew point annealing was performed, and the ferrite was not stabilized. Therefore, the depth where the C concentration is 0.05% or less and the thickness of the layer where the area ratio of the ferrite phase is 90% or more were not large. As a result, the LME resistance and hydrogen desorption properties were poor.
  • No. No. 42 is considered to be because a brush with a large amount of grinding was used in the pretreatment process, which resulted in increased roughness of the steel plate surface and unstable ferrite phase. Therefore, the thickness of the layer in which the area ratio of the ferrite phase was 90% or more did not increase. As a result, the LME resistance and hydrogen desorption properties were poor.
  • No. Examples 1 to 25 of the present invention had high LME resistance and hydrogen desorption properties. It was confirmed that examples in which the depth of the C concentration is 0.05% or less and the thickness of the layer where the area ratio of the ferrite phase is 90% or more have particularly excellent LME resistance.
  • the present invention it is possible to provide high-strength steel sheets and plated steel sheets that have high LME resistance and hydrogen desorption properties, and the steel sheets and plated steel sheets are used for automobiles, home appliances, building materials, etc., especially for automobiles. It can be suitably used for. Therefore, the present invention has extremely high industrial applicability.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Abstract

La présente invention aborde le problème de la fourniture d'une tôle d'acier et d'une tôle d'acier plaquée qui ont une résistance élevée au LME et une désorption d'hydrogène. Cette tôle d'acier et cette tôle d'acier plaquée sont caractérisées : en ce qu'elles ont des composants chimiques prescrits ; en ce que la profondeur dans la direction de la profondeur à partir de la surface des tôles d'acier à laquelle la concentration C telle que mesurée par GDS n'est pas supérieure à 0,05 % est d'au moins 10 µm ; en ce que l'épaisseur dans la direction de la profondeur à partir de la surface des tôles d'acier d'une couche qui a une fraction de surface de phase de ferrite d'au moins 90 % est d'au moins 20 µm ; et en ce que la rugosité de surface Ra des tôles d'acier n'est pas supérieure à 3,0 µm.
PCT/JP2023/032500 2022-09-06 2023-09-06 Tôle d'acier et tôle d'acier plaquée WO2024053667A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2022141638 2022-09-06
JP2022-141638 2022-09-06

Publications (1)

Publication Number Publication Date
WO2024053667A1 true WO2024053667A1 (fr) 2024-03-14

Family

ID=90191241

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2023/032500 WO2024053667A1 (fr) 2022-09-06 2023-09-06 Tôle d'acier et tôle d'acier plaquée

Country Status (1)

Country Link
WO (1) WO2024053667A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020130631A1 (fr) * 2018-12-19 2020-06-25 주식회사 포스코 Tôle d'acier galvanisée à haute résistance ayant une excellente soudabilité par point de résistance électrique et son procédé de fabrication
KR20220019867A (ko) * 2020-08-10 2022-02-18 주식회사 포스코 우수한 점용접성, 강도 및 성형성을 갖는 냉연강판 및 그 제조방법
WO2022097738A1 (fr) * 2020-11-06 2022-05-12 Ｊｆｅスチール株式会社 FEUILLE D'ACIER ÉLECTROPLAQUÉE À BASE DE Fe, FEUILLE D'ACIER GALVANISÉE PAR IMMERSION À CHAUD ALLIÉE ET LEURS PROCÉDÉS DE FABRICATION
WO2022149507A1 (fr) * 2021-01-08 2022-07-14 日本製鉄株式会社 Joint de soudure et composant d'automobile
WO2022149505A1 (fr) * 2021-01-08 2022-07-14 日本製鉄株式会社 Joint soudé et pièce de véhicule
WO2022149511A1 (fr) * 2021-01-08 2022-07-14 日本製鉄株式会社 Joint soudé et composant d'automobile

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020130631A1 (fr) * 2018-12-19 2020-06-25 주식회사 포스코 Tôle d'acier galvanisée à haute résistance ayant une excellente soudabilité par point de résistance électrique et son procédé de fabrication
KR20220019867A (ko) * 2020-08-10 2022-02-18 주식회사 포스코 우수한 점용접성, 강도 및 성형성을 갖는 냉연강판 및 그 제조방법
WO2022097738A1 (fr) * 2020-11-06 2022-05-12 Ｊｆｅスチール株式会社 FEUILLE D'ACIER ÉLECTROPLAQUÉE À BASE DE Fe, FEUILLE D'ACIER GALVANISÉE PAR IMMERSION À CHAUD ALLIÉE ET LEURS PROCÉDÉS DE FABRICATION
WO2022149507A1 (fr) * 2021-01-08 2022-07-14 日本製鉄株式会社 Joint de soudure et composant d'automobile
WO2022149505A1 (fr) * 2021-01-08 2022-07-14 日本製鉄株式会社 Joint soudé et pièce de véhicule
WO2022149511A1 (fr) * 2021-01-08 2022-07-14 日本製鉄株式会社 Joint soudé et composant d'automobile

Similar Documents

Publication Publication Date Title
CN111492075B (zh) 钢板、热浸镀锌钢板和合金化热浸镀锌钢板
JP6525114B1 (ja) 高強度亜鉛めっき鋼板およびその製造方法
JP6777173B2 (ja) スポット溶接用高強度亜鉛めっき鋼板
CN108291283B (zh) 高强度热浸镀锌钢板及用于其的热轧钢板和冷轧钢板的制造方法、高强度热浸镀锌钢板
EP2474639A1 (fr) Feuille d'acier galvanisé à chaud très résistante et son procédé de production
KR101918876B1 (ko) 용융 아연 도금 강판
JP4932363B2 (ja) 高強度合金化溶融亜鉛めっき鋼板及びその製造方法
EP3663424A1 (fr) Tôle d'acier zinguée au trempé
US11492679B2 (en) Hot-rolled steel sheet and method for manufacturing same
CN106661657A (zh) 高强度热镀锌钢板的制造方法
WO2020136988A1 (fr) Tôle en acier galvanisé à chaud hautement résistante, et procédé de fabrication de celle-ci
WO2022230064A1 (fr) Feuille d'acier et feuille d'acier plaquée
CN116694886A (zh) 薄钢板的制造方法和镀覆钢板的制造方法
WO2022215389A1 (fr) Tôle d'acier laminée à froid à haute résistance et son procédé de fabrication
CN113272465B (zh) 高强度冷轧钢板及其制造方法
WO2022230400A1 (fr) Tôle d'acier et tôle d'acier plaquée
WO2023054717A1 (fr) Élément soudé en acier
JP5835547B2 (ja) Ｓｉ含有冷延鋼板の製造方法
WO2024053667A1 (fr) Tôle d'acier et tôle d'acier plaquée
WO2024053663A1 (fr) Tôle d'acier plaquée
WO2024053669A1 (fr) Joint soudé
WO2024053665A1 (fr) Joint soudé
WO2022230399A1 (fr) Feuille d'acier et feuille d'acier plaquée
WO2023054705A1 (fr) Tôle d'acier plaquée
WO2022230401A1 (fr) Tôle d'acier et tôle d'acier plaquée

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: 23863205

Country of ref document: EP

Kind code of ref document: A1