WO2021193632A1 - Tôle d'acier allié galvanisée par immersion à chaud - Google Patents

Tôle d'acier allié galvanisée par immersion à chaud Download PDF

Info

Publication number
WO2021193632A1
WO2021193632A1 PCT/JP2021/011993 JP2021011993W WO2021193632A1 WO 2021193632 A1 WO2021193632 A1 WO 2021193632A1 JP 2021011993 W JP2021011993 W JP 2021011993W WO 2021193632 A1 WO2021193632 A1 WO 2021193632A1
Authority
WO
WIPO (PCT)
Prior art keywords
less
hot
steel sheet
dip galvanized
galvanized steel
Prior art date
Application number
PCT/JP2021/011993
Other languages
English (en)
Japanese (ja)
Inventor
庄太 菊池
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 CN202180023035.5A priority Critical patent/CN115298345A/zh
Priority to JP2022510548A priority patent/JP7348577B2/ja
Priority to KR1020227031750A priority patent/KR20220139985A/ko
Priority to MX2022011603A priority patent/MX2022011603A/es
Priority to EP21776766.4A priority patent/EP4130319A4/fr
Priority to US17/909,231 priority patent/US20230093068A1/en
Publication of WO2021193632A1 publication Critical patent/WO2021193632A1/fr

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
    • B32B15/013—Layered products comprising a layer of metal all layers being exclusively metallic one layer being formed of an iron alloy or steel, another layer being formed of a metal other than iron or aluminium
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—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
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/021—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular fabrication or treatment of ingot or slab
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0278—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular surface treatment
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/10—Ferrous alloys, e.g. steel alloys containing cobalt
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium 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
    • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium 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
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium 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
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium 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
    • C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—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
    • 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 hot-dip galvanized steel sheets.
  • the present application claims priority based on Japanese Patent Application No. 2020-057273 filed in Japan on March 27, 2020, the contents of which are incorporated herein by reference.
  • Hot stamping is a process of pressing a blank that has been heated to a temperature above the austenite single-phase region (Ac 3 points) (for example, heated to about 900 ° C.), and is rapidly cooled with a mold at the same time as molding and quenched. It is a technology. According to this technique, it is possible to produce a press-molded product having high shape freezing property and high strength.
  • Patent Document 1 includes a heating step of heating a galvanized steel sheet to an Ac 3 transformation point or higher, and a hot press forming step of performing hot press forming at least twice after the heating step.
  • a hot press-formed steel member is disclosed, which is manufactured by performing any hot press forming in a hot press forming step so as to satisfy a predetermined formula.
  • Patent Document 1 does not consider welding during spot welding.
  • the present inventor investigated the cause of welding during spot welding. As a result, the present inventor found that the welding at the time of spot welding is greatly affected by the voids (vacancy) in the zinc-based plating layer (hot-stamped molten zinc-based plating layer) of the hot stamped product. It was found that the smaller the voids in the system plating layer, the more the welding during spot welding is suppressed. According to the present inventor, the presence of voids in the zinc-based plating layer locally narrows the energization path, and an overcurrent flows through the voids, which causes overheating, which facilitates welding between the electrode and the zinc-based plating layer. Thought.
  • the voids formed in the hot stamped body are the difference in heat shrinkage between the base material and the hot-dip galvanized plating layer during hot stamping and the different phases in the plating layer. It was considered to be due to the difference in heat shrinkage between them.
  • the present inventor has investigated a method for reducing the difference in heat shrinkage during hot stamping. As a result, in the hot-dip galvanized steel sheet, the average crystal grain size of the surface layer region of the steel sheet is 4.0 ⁇ m or less, the standard deviation of the crystal grain size is 2.0 ⁇ m or less, and the steel sheet and hot-dip galvanized steel sheet. It was found that the generation of voids can be suppressed by setting the maximum Al concentration of the boundary layer existing between the system plating layer to 0.30 mass% or more.
  • the present inventor presumes that the mechanism by which void formation in the hot-dip galvanized layer is suppressed by configuring the surface layer region and the boundary layer of the steel sheet as described above is as follows.
  • Al is uniformly diffused and concentrated in the boundary layer (a Fe—Al alloy layer is formed). It is considered that void formation is suppressed by concentrating Al, which has a linear expansion coefficient between Fe and Zn, in the boundary layer and alleviating the difference in heat shrinkage between the base metal and the hot-dip galvanized plating layer.
  • the difference in thermal shrinkage between different phases in the plating layer that is, the ⁇ phase having a high Zn concentration (Fe concentration is 10 to 30% by mass) and the solid solution of Fe—Zn having a high Fe concentration (Fe concentration is 50 to 80% by mass). Therefore, it is considered that the boundary between the ⁇ phase and the Fe—Zn solid solution becomes the starting point of void generation.
  • the Fe—Zn alloying reaction during hot stamp heating is suppressed, and the increase in the void generation starting point (the boundary between the ⁇ phase and the Fe—Zn solid solution) is suppressed. It is presumed that this will reduce the voids formed in the zinc-based plating layer of the hot stamped body.
  • the inventor of the present invention has found that it is effective to control the hot rolling conditions in order to refine and sizing the crystal grains in the surface layer region of the steel sheet.
  • the present inventor can control the temperature distribution in the surface layer region of the steel sheet by controlling the water pressure at the time of descaling performed on the finish rolling inlet side in the finish rolling of hot rolling, and as a result, the surface layer of the steel sheet. It was found that the crystal grains in the region can be refined and sized.
  • the hot-dip galvanized steel sheet according to one aspect of the present invention comprises a steel sheet, a boundary layer arranged on the surface of the steel sheet, and a hot-dip galvanized steel sheet arranged on the surface of the boundary layer.
  • the chemical composition of the steel sheet is mass%. C: 0.18% or more, 0.50% or less, Si: 0.10% or more, 1.50% or less, Mn: 0.5% or more, 2.5% or less, sol.
  • Al 0.001% or more, 0.100% or less, Ti: 0.010% or more, 0.100% or less, S: 0.0100% or less, P: 0.100% or less, N: 0.010% or less, Nb: 0% or more, 0.05% or less V: 0% or more, 0.50% or less, Cr: 0% or more, 0.50% or less, Mo: 0% or more, 0.50% or less, B: 0% or more, 0.010% or less, Ni: 0% or more and 2.00% or less, and the total of REM, Ca, Co and Mg: 0% or more and 0.0300% or less, and the balance is Fe and impurities.
  • the average crystal grain size is 4.0 ⁇ m or less, and the standard deviation of the crystal grain size is 2.0 ⁇ m or less.
  • the maximum Al concentration is 0.30 mass% or more.
  • Nb 0.02% or more, 0.05% or less V: 0.005% or more, 0.50% or less, Cr: 0.10% or more, 0.50% or less, Mo: 0.005% or more, 0.50% or less, B: 0.0001% or more, 0.010% or less, Ni: 0.01% or more, 2.00% or less, and total of REM, Ca, Co and Mg: 0.0003% or more, 0.0300% or less, one or more selected from the group. It may be contained.
  • the hot-dip galvanized steel sheet according to the above [1] or [2] may contain C: 0.24% or more and 0.50% or less in mass% of the chemical composition.
  • the hot-dip galvanized steel sheet according to the present embodiment includes a steel sheet, a boundary layer arranged on the steel sheet, and a hot-dip galvanized steel sheet arranged on the boundary layer.
  • a steel sheet constituting the hot-dip galvanized steel sheet according to the present embodiment will be described.
  • the reasons for limiting the chemical composition of the steel sheet constituting the hot-dip galvanized steel sheet according to the present embodiment will be described below. All% of the chemical composition indicates mass%.
  • the chemical composition of the steel sheet constituting the hot-dip galvanized steel sheet according to the present embodiment is, in mass%, C: 0.18% or more, 0.50% or less, Si: 0.10% or more, 1.50% or less, Mn: 0.5% or more, 2.5% or less, sol.
  • Fe and impurities are included.
  • each element will be described.
  • Carbon (C) increases the strength of the hot stamped molded product after hot stamping. If the C content is too low, the above effect cannot be obtained. Therefore, the C content is set to 0.18% or more. Preferably, it is 0.20% or more, 0.24% or more, and 0.25% or more. On the other hand, if the C content is too high, the toughness of the hot-dip galvanized steel sheet decreases. Therefore, the C content is set to 0.50% or less. Preferably, it is 0.45% or less and 0.40% or less.
  • Si 0.10% or more, 1.50% or less
  • Si is an element that improves the fatigue characteristics of the hot stamped article.
  • Si is also an element that improves hot-dip galvanizing property, particularly plating wettability, by forming a stable oxide film on the surface of the steel sheet during recrystallization annealing.
  • the Si content is set to 0.10% or more. Preferably, it is 0.15% or more and 0.18% or more.
  • the Si content is too high, Si in the steel diffuses during heating during hot stamping, and an oxide is formed on the surface of the steel sheet. The oxide formed on the surface of the steel sheet reduces the phosphate treatment property.
  • Si is also an element that raises the Ac 3 points of the hot-dip galvanized steel sheet.
  • the Si content is set to 1.50% or less.
  • it is 1.40% or less, 1.20% or less, and 1.00% or less.
  • Mn 0.5% or more, 2.5% or less
  • Mn is an element that improves the hardenability of steel.
  • the Mn content is 0.5% or more in order to improve the hardenability and obtain the desired strength in the hot stamped molded product. Preferably, it is 1.0% or more and 1.5% or more.
  • the Mn content is set to 2.5% or less. Preferably, it is 2.1% or less and 2.0% or less.
  • sol. Al 0.001% or more, 0.100% or less
  • Al is an element that deoxidizes molten steel and suppresses the formation of oxides that are the starting point of fracture. Al is also an element having an action of suppressing the alloying reaction of Zn and Fe and an action of improving the corrosion resistance of the hot stamped molded product.
  • the Al content is 0.001% or more. Preferably, it is 0.005% or more.
  • the Al content is 0.100% or less. Preferably, it is 0.090% or less, 0.070% or less, and 0.050% or less.
  • sol. Al means acid-soluble Al, and indicates solid solution Al existing in steel in a solid solution state.
  • Ti 0.010% or more, 0.100% or less
  • Ti is an element that enhances oxidation resistance after hot-dip galvanizing. Further, Ti is also an element that improves the hardenability of a steel sheet by combining with N in steel to form a nitride (TiN) and suppressing B from becoming a nitride (BN).
  • the Ti content is 0.010% or more. Preferably, it is 0.020% or more.
  • the Ti content when the Ti content is excessive, the Ac 3 point rises and the heating temperature at the time of hot stamping rises, which lowers the productivity and promotes the solid solution formation into the Fe—Zn solid solution. Therefore, it may be difficult to secure the ⁇ phase.
  • the Ti content is set to 0.100% or less. It is preferably 0.070% or less.
  • S 0.0100% or less
  • S is an element contained as an impurity, which forms sulfide in steel to deteriorate the toughness of the hot stamped compact and lower the delayed fracture resistance. Therefore, the S content is set to 0.0100% or less. Preferably, it is 0.0050% or less.
  • the S content is preferably 0%, but the S content may be 0.0001% or more because the cost of removing S increases if the S content is excessively reduced.
  • P 0.100% or less
  • P is an element contained as an impurity and segregates at grain boundaries to deteriorate the toughness and delayed fracture resistance of steel. Therefore, the P content is set to 0.100% or less. Preferably, it is 0.050% or less. The P content is preferably 0%, but the P content may be 0.001% or more because the de-P cost increases if the P content is excessively reduced.
  • N 0.010% or less
  • N is an impurity element, which is an element that forms coarse nitrides in steel to reduce the toughness of steel. Further, N is also an element that facilitates the generation of blow holes during spot welding. Further, when B is contained, N combines with B to reduce the amount of solid solution B and deteriorate the hardenability of the steel sheet. Therefore, the N content is set to 0.010% or less. Preferably, it is 0.007% or less. The N content is preferably 0%, but the N content may be 0.0001% or more because the production cost increases if the N content is excessively reduced.
  • the balance of the chemical composition of the steel sheet constituting the hot-dip galvanized steel sheet according to the present embodiment is Fe and impurities. Impurities are allowed as long as they are inevitably mixed from the steel raw material or scrap and / or in the steelmaking process and do not impair the characteristics of the hot stamped molded product obtained by hot stamping the hot-dip galvanized steel sheet according to the present embodiment. Elements are exemplified.
  • the steel sheet constituting the hot-dip galvanized steel sheet according to the present embodiment may contain the following elements as optional elements instead of a part of Fe.
  • the content is 0%.
  • Nb 0% or more, 0.05% or less
  • Nb has an action of forming carbides and refining crystal grains at the time of hot stamping. By refining the crystal grains, the toughness of the steel is increased.
  • the Nb content is preferably 0.02% or more. However, if the Nb content is too high, the above effects may be saturated and the hardenability of steel may be reduced. Therefore, the Nb content is set to 0.05% or less.
  • V 0% or more
  • 0.50% or less V is an element that improves the strength by finely forming carbonitride in steel.
  • the V content is preferably 0.005% or more.
  • the V content is set to 0.50% or less.
  • Cr 0% or more
  • 0.50% or less Cr is an element that improves the hardenability of steel.
  • the Cr content is preferably 0.10% or more.
  • the Cr content is set to 0.50% or less.
  • Mo 0% or more, 0.50% or less Mo is an element that enhances the hardenability of steel. In order to surely obtain this effect, the Mo content is preferably 0.005% or more. However, if the Mo content is too high, the above effect will be saturated. Therefore, the Mo content is 0.50% or less.
  • B 0% or more, 0.010% or less
  • B is an element that improves the hardenability of steel.
  • the B content is preferably 0.0001% or more.
  • the B content is set to 0.010% or less.
  • Ni 0% or more, 2.00% or less
  • Ni has the effect of improving the toughness of steel, the effect of suppressing embrittlement caused by the liquid phase Zn during heating of hot stamping, and the effect of improving the hardenability of steel. It is an element that has.
  • the Ni content is preferably 0.01% or more. On the other hand, even if the Ni content exceeds 2.00%, the above effect is saturated. Therefore, the Ni content is set to 2.00% or less.
  • Total of REM, Ca, Co and Mg 0% or more, 0.0300% or less REM, Ca, Co and Mg control sulfides and oxides in a preferable shape and suppress the formation of coarse inclusions. Therefore, it is an element that suppresses the occurrence of cracks during spot welding.
  • the total content of REM, Ca, Co and Mg is preferably 0.0003% or more.
  • the content of any one of REM, Ca, Co and Mg may be 0.0003% or more.
  • the total content of REM, Ca, Co and Mg is more than 0.0300%, inclusions are excessively generated and cracks are likely to occur during spot welding. Therefore, the total content of REM, Ca, Co and Mg is 0.0300% or less.
  • the chemical composition of the above-mentioned steel sheet may be measured by a general analysis method.
  • ICP-AES Inductively Coupled Plasma-Atomic Emission Spectrometry
  • C and S may be measured by using the combustion-infrared absorption method
  • N may be measured by using the inert gas melting-thermal conductivity method.
  • sol. Al may be measured by ICP-AES using a filtrate obtained by heat-decomposing the sample with an acid.
  • the hot-dip zinc-based plating layer arranged on the surface of the hot-dip galvanized steel sheet may be removed by mechanical grinding, and then the chemical composition may be analyzed.
  • the steel sheet constituting the hot-dip galvanized steel sheet according to the present embodiment has the above chemical composition, the average crystal grain size is 4.0 ⁇ m or less in the surface layer region, and the standard deviation of the crystal grain size is 2.0 ⁇ m or less. Is.
  • the surface layer region of the steel sheet constituting the hot-dip galvanized steel sheet according to the present embodiment will be described.
  • the average crystal grain size is 4.0 ⁇ m or less, and the standard deviation of the crystal grain size is 2.0 ⁇ m or less. It means that. If the average crystal grain size in this surface layer region is more than 4.0 ⁇ m or the standard deviation of the crystal grain size is more than 2.0 ⁇ m, the evaporation of zinc in the molten zinc-based plating layer during heating during hot stamping cannot be suppressed. A large amount of voids are formed in the hot stamped body. As a result, the desired spot weldability cannot be obtained in the hot stamp molded product. Therefore, in the surface layer region of the steel sheet, the average crystal grain size is 4.0 ⁇ m or less, and the standard deviation of the crystal grain size is 2.0 ⁇ m or less.
  • the average crystal grain size in the surface layer region of the steel sheet is small, it may be 3.5 ⁇ m or less and 3.0 ⁇ m or less. Further, since the smaller the standard deviation of the crystal grain size in the surface layer region of the steel sheet is, the more preferable it is, it may be 1.8 ⁇ m or less and 1.5 ⁇ m or less.
  • the lower limit of the average crystal grain size in the surface layer region of the steel sheet is not particularly limited, but may be 1.5 ⁇ m. Further, the lower limit of the standard deviation of the crystal grain size in the surface layer region of the steel sheet is not particularly limited, but may be 1.0 ⁇ m.
  • the standard deviation of the average crystal grain size and crystal grain size in the surface layer region is measured by the EBSP-OIM (Electron Backscatter Diffraction Pattern-Orientation Image Microscopic) method. do.
  • the EBSP-OIM method is performed using a device that combines a scanning electron microscope and an EBSP analyzer and an OIM Analysis (registered trademark) manufactured by AMETEK.
  • the analysis is performed in a region of 1200 times magnification and 40 ⁇ m ⁇ 30 ⁇ m in at least 5 fields of view.
  • a place where the angle difference between adjacent measurement points is 5 ° or more is defined as a crystal grain boundary, the equivalent circle diameter of the crystal grain is calculated, and this is regarded as the crystal grain size.
  • the average value of the crystal grain size of the obtained crystal grains is obtained.
  • the standard deviation from the crystal grain size of the obtained crystal grains the standard deviation of the crystal grain size in the surface layer region is obtained.
  • the steel plate, the boundary layer, and the hot-dip galvanized layer may be specified by the method described later, and the above-mentioned measurement may be performed on the surface layer region of the region specified as the steel plate.
  • the concentrations (mass%) of Fe, Zn and Al are measured by GDS (glow discharge emission analysis) from the surface to a depth direction (plate thickness direction) up to 50 ⁇ m.
  • GDS low discharge emission analysis
  • the GDS profile as shown in FIG. 1 can be obtained.
  • the depth range in which the Fe concentration is 85% by mass or more is defined as the steel sheet
  • the depth range in which the Zn concentration is 90% by mass or more is defined as the hot-dip galvanized layer.
  • the depth range between the steel sheet and the hot-dip galvanized layer is defined as the boundary layer.
  • the metallographic structure of the steel sheet is not particularly limited as long as the desired strength and spot weldability can be obtained after hot stamping, but in% area, ferrite: 20 to 90%, bainite and martensite: 0 to 100%, pearlite: 10 -80% and retained austenite: may consist of 0-5%.
  • the metallographic structure of the steel sheet may be measured by the following method.
  • the area ratio of ferrite and pearlite is measured by the following method.
  • the cross section parallel to the rolling direction is mirror-finished and polished at room temperature with colloidal silica containing no alkaline solution for 8 minutes to remove the strain introduced into the surface layer of the sample.
  • the length is 50 ⁇ m, 1/8 depth from the surface to 3/8 of the plate thickness, so that the 1/4 depth from the surface can be analyzed at any position in the longitudinal direction of the sample cross section.
  • Crystal orientation information is obtained by measuring the depth region by electron backscatter diffraction at measurement intervals of 0.1 ⁇ m.
  • an apparatus composed of a thermal field emission scanning electron microscope (JSM-7001F manufactured by JEOL) and an EBSP detector (DVC5 type detector manufactured by TSL) is used.
  • the degree of vacuum in the apparatus is 9.6 ⁇ 10 -5 Pa or less
  • the acceleration voltage is 15 kV
  • the irradiation current level is 13
  • the electron beam irradiation level is 62.
  • the reflected electron image is taken in the same field of view.
  • the area ratio of pearlite is obtained by identifying the crystal grains in which ferrite and cementite are deposited in layers from the reflected electron image and calculating the area ratio of the crystal grains. After that, for the crystal grains excluding the crystal grains determined to be pearlite, the obtained crystal orientation information is used for the "Grain Average Misorition" function installed in the software "OIM Analysis (registered trademark)" attached to the EBSP analysis device. Therefore, a region having a Grain Average crystallization value of 1.0 ° or less is determined to be ferrite. The area ratio of ferrite is obtained by obtaining the area ratio of the region determined to be ferrite.
  • the area ratio of retained austenite is measured by backscattered electron diffraction image (EBSP).
  • EBSP backscattered electron diffraction image
  • a sample taken at the same sampling position as when measuring the volume fraction of ferrite described above is used, and the surface can be analyzed at a depth of 1/4 of the thickness from the surface of the hot-rolled steel sheet. From 1/8 depth of the plate thickness to 3/8 depth of the plate thickness from the surface.
  • the sample is polished using # 600 to # 1500 silicon carbide paper, and then mirror-finished using a diluted solution such as alcohol or a liquid in which diamond powder having a particle size of 1 to 6 ⁇ m is dispersed in pure water.
  • electrolytic polishing in order to remove mechanical polishing strain on the observation surface, a minimum of 20 ⁇ m may be polished and a maximum of 50 ⁇ m may be polished. Considering the sagging of the end portion, it is preferably 30 ⁇ m or less.
  • the acceleration voltage is set to 15 to 25 kV, and the measurement is performed at intervals of at least 0.25 ⁇ m, and the crystal orientation information of each measurement point in the range of 150 ⁇ m or more in the plate thickness direction and 250 ⁇ m or more in the rolling direction is obtained. ..
  • those having a crystal structure of fcc are determined to be retained austenite by using the "Phase Map" function installed in the software "OIM Analysis (registered trademark)" attached to the EBSP analyzer.
  • the area ratio of retained austenite is obtained by obtaining the ratio of the measurement points determined to be retained austenite.
  • the measurement interval is narrow and the measurement range is wide.
  • the measurement interval is 0.01 ⁇ m or more.
  • the measurement range may be 200 ⁇ m in the plate thickness direction and 400 ⁇ m in the plate width direction at the maximum.
  • an apparatus composed of a thermal field emission scanning electron microscope (JSM-7001F manufactured by JEOL) and an EBSP detector (DVC5 type detector manufactured by TSL) is used. At this time, the degree of vacuum in the apparatus is 9.6 ⁇ 10 -5 Pa or less, the irradiation current level is 13, and the electron beam irradiation level is 62.
  • the total area ratio of bainite and martensite in the present embodiment shall be a value obtained by subtracting the total of the area ratio of ferrite and pearlite and the volume ratio of retained austenite measured by the above method from 100%.
  • the hot-dip galvanized steel sheet according to the present embodiment includes the above-mentioned steel sheet, a boundary layer arranged on the steel sheet, and a hot-dip galvanized steel sheet arranged on the boundary layer.
  • the boundary layer and the hot-dip galvanized layer will be described.
  • Boundary layer Maximum Al concentration of 0.30 mass% or more
  • the boundary layer means a layer existing between the above-mentioned steel sheet and the hot-dip galvanized layer described later.
  • the boundary layer constituting the hot-dip galvanized steel sheet according to the present embodiment has a maximum Al concentration of 0.30 mass% or more. If the maximum Al concentration in the boundary layer is less than 0.30 mass%, the desired spot weldability cannot be obtained in the hot stamp molded product. Therefore, the maximum Al concentration in the boundary layer is set to 0.30 mass% or more. Preferably, it is 0.35 mass% or more and 0.40 mass% or more. The higher the maximum Al concentration in the boundary layer is, the more preferable it is. Therefore, the upper limit does not need to be specified, but it may be 1.00 mass%.
  • the maximum Al concentration in the boundary layer is measured by the following method.
  • the concentrations (mass%) of Fe, Zn and Al are measured by GDS (glow discharge emission analysis) from the surface to 50 ⁇ m in the depth direction (plate thickness direction) at any five locations on the hot-dip galvanized steel sheet.
  • the depth range in which the Fe concentration is 85% by mass or more is defined as the steel sheet
  • the depth range in which the Zn concentration is 90% by mass or more is defined as the hot-dip galvanized layer
  • the maximum Al concentration (% by mass) in the boundary layer when the depth range between the plating layer and the boundary layer is defined as the boundary layer is obtained.
  • the maximum Al concentration in the boundary layer is obtained by calculating the average value of the maximum Al concentration in the boundary layer at each measurement point.
  • the hot-dip galvanized layer means a layer having a Zn concentration of 90% by mass or more.
  • the hot-dip galvanized layer contains 0.01% by mass or more and 1.00% by mass or less of Al as an element other than Zn. Further, Fe may be contained in an amount of 10% by mass or less as the balance.
  • the plate thickness of the hot-dip galvanized steel sheet according to the present embodiment is not particularly limited, but is preferably 0.5 to 3.5 mm from the viewpoint of weight reduction of the vehicle body.
  • a method for manufacturing the hot-dip galvanized steel sheet according to the present embodiment will be described.
  • a slab having the above-mentioned chemical composition is heated to 1200 ° C. or higher, held in a temperature range of 1200 ° C. or higher for 20 minutes or longer, and then hot-rolled. Finish rolling is completed in a temperature range of 810 ° C. or higher, and winding is performed in a temperature range of 750 ° C. or lower.
  • the surface layer region of the steel sheet is made finer and sized, that is, the average crystal grain size in the surface layer region is 4.0 ⁇ m or less, and the standard deviation of the crystal grain size is 2.
  • the water pressure of descaling in finish rolling is controlled so as to be 0.0 ⁇ m or less.
  • Descaling is a step of removing scale formed on the surface of a steel sheet by injecting water onto the upper and lower surfaces of the steel sheet with a nozzle. When descaling is performed by injecting water from a plurality of nozzles, the maximum water pressure among the water pressures of the plurality of nozzles is controlled to be within the range of the water pressure described later.
  • the slab after rough rolling is rolled by a plurality of finish rolling machines.
  • the hydraulic pressure in the descaling after the rough rolling and before the first pass of finish rolling (before F1) and after the first pass of finish rolling (after F1) is applied.
  • the descaling water pressure is proportional to the cooling capacity.
  • the water pressure is 10 MPa or more and 40 MPa or less.
  • the descaling before F1 is performed for the purpose of removing the scale formed on the surface of the steel sheet.
  • the water pressure of descaling before F1 is less than 10 MPa, the scale peeled off during finish rolling is bitten, the unevenness of the hot-rolled plate becomes remarkable, and it remains as a pattern even after pickling and cold rolling, resulting in poor appearance. cause.
  • the descaling water pressure before F1 is set to 10 MPa or more.
  • descaling before F1 is generally performed for the purpose of removing scale, but if the water pressure of descaling before F1 is too high, the desired average crystal grain size and crystal grain size in the surface layer region of the steel plate Cannot get the standard deviation of. Therefore, the descaling water pressure before F1 is set to 40 MPa or less.
  • descaling is performed after rough rolling and before the first pass of finish rolling (before F1) and after the first pass of finish rolling (after F1), descaling is also performed after the second pass of finish rolling (after F2). Is preferable.
  • the standard deviation of the crystal grains in the surface layer region of the steel sheet can be made smaller, and as a result, the spot weldability of the hot-dip galvanized steel sheet can be further improved.
  • the water pressure is preferably 2 MPa or more and 10 MPa or less.
  • the descaling after the third pass of finish rolling is not particularly limited.
  • cold rolling is performed as necessary and hot dip galvanizing is performed.
  • Pickling may be performed between hot rolling and cold rolling.
  • the cold rolling may be a normal cumulative reduction rate, for example, cold rolling in which the cumulative reduction rate is 30 to 90%.
  • Hot-dip galvanizing may be performed using a continuous hot-dip galvanizing line.
  • the amount of the hot-dip galvanized plating layer adhered is not particularly limited, and may be a general one.
  • the amount of plating adhered to one side may be 5 to 150 g / m 2.
  • the hot-dip galvanized layer is alloyed to form an alloyed hot-dip galvanized layer
  • the high Zn concentration ⁇ phase in the plating layer exhibiting the sacrificial anticorrosion effect disappears and the corrosion resistance is lowered.
  • Electrogalvanization is not desirable because it requires additive elements to delay alloying and increases manufacturing costs.
  • the hot-dip galvanized steel sheet according to the present embodiment can be manufactured.
  • the heating temperature is from the higher temperature of "Ac 3 points and 800 ° C.” to 950 ° C.
  • the heating time time from putting the hot-dip galvanized steel sheet in the heating furnace to holding it at the heating temperature and taking out the hot-dip galvanized steel sheet from the heating furnace (time from carrying in the heating furnace to carrying out the heating furnace)). It is preferably 60 to 600 seconds.
  • the three Ac points are represented by the following formula (1).
  • the average heating rate during heating may be 0.1 to 200 ° C./s.
  • the average heating rate here is a value obtained by dividing the temperature difference between the surface temperature of the steel sheet at the start of heating and the heating temperature by the time difference from the start of heating to the time when the heating temperature is reached. For holding in the temperature range of the higher temperature of "Ac 3 points and 800 ° C.” to 950 ° C., the temperature of the steel sheet may be changed or kept constant.
  • Examples of the heating method before hot stamping include heating by an electric furnace or a gas furnace, flame heating, energization heating, high frequency heating, induction heating, and the like.
  • hot stamping is performed. After hot stamping, it is preferable to perform cooling at an average cooling rate of 20 to 500 ° C./s, for example, up to a temperature range of 250 ° C. or lower.
  • a hot stamped molded product produced by using the hot-dip galvanized steel sheet according to the present embodiment can be obtained.
  • This hot stamped body has excellent spot weldability because the formation of voids in the zinc-based plated layer (hot-dip galvanized layer after hot stamping) is suppressed, and is generally required for hot stamped bodies. Has strength.
  • the conditions in the examples are one condition example adopted for confirming the feasibility and effect of the present invention, and the present invention is described in this one condition example. It is not limited. In the present invention, various conditions can be adopted as long as the gist of the present invention is not deviated and the object of the present invention is achieved.
  • a slab produced by casting molten steel having the chemical composition shown in Table 1-1 and Table 1-2 is heated to 1200 ° C. or higher and held for 20 minutes or longer, and then the finish rolling completion temperature is 810 ° C. or higher.
  • a steel sheet was obtained by hot rolling and then cold rolling.
  • water was sprayed onto the upper and lower surfaces of the steel sheet at the hydraulic pressures shown in Tables 2-1 and 2-2 to perform descaling.
  • "before F1" indicates the descaling water pressure (MPa) after rough rolling and before the first pass of finish rolling, and is "after F1 (between F1 and F2)".
  • "after F2 (between F2 and F3)" indicates the water pressure (MPa) in the descaling after the second pass of the finish rolling.
  • the cumulative rolling reduction during cold rolling was 30 to 90%.
  • hot-dip galvanized steel sheets shown in Tables 2-1 and 2-2 were obtained.
  • the amount of the hot-dip galvanized plating layer adhered was 5 to 150 g / m 2 per side.
  • the average crystal grain size and standard deviation of the crystal grain size in the surface layer region of the steel sheet, the metal structure of the steel sheet, and the maximum Al concentration of the boundary layer were measured by the above method.
  • the hot stamped compacts shown in Table 2-1 and Table 2-2 were produced under the conditions shown in Table 2-1 and Table 2-2.
  • the average heating rate in heating before hot stamping was 0.1 to 200 ° C./s, and after hot stamping, the mixture was cooled to a temperature range of 250 ° C. or lower at an average cooling rate of 20 to 500 ° C./s.
  • the underline in the table indicates that it is out of the scope of the present invention, that it is out of the preferable manufacturing conditions, or that the characteristic value is not preferable.
  • the cross-sectional area ratio of voids in the zinc-based plating layer constituting the hot stamped molded product was measured by the following method. First, a sample is cut out so that a cross section perpendicular to the surface (thick cross section) can be observed from an arbitrary position 50 mm or more away from the end face of the hot stamped molded product (a position avoiding the end if it cannot be collected from this position). rice field. The size of the sample was set so that it could be observed by about 10 mm in the rolling direction.
  • the observed cross section was polished, photographed at a magnification of 300 times using an SEM (scanning electron microscope), and then the cross-sectional area ratio of the void was calculated by binarized image processing.
  • the built-in software of the digital microscope VHX-5000 manufactured by KEYENCE Co., Ltd. was used to discriminate the void based on the brightness and automatically measure the area of the void.
  • the steel plate and the zinc-based plating layer constituting the hot stamped body are subjected to line analysis along the plate thickness direction using SEM-EDS (Energy Dispersive X-ray Spectroscopy) to quantitatively analyze the Fe concentration. It was determined by.
  • SEM Single Electrode Deformation
  • EDS XFlash (r) 6 ⁇ 30 manufactured by Bruker AXS Corporation
  • EDS analysis software ESPRIT 1.9 manufactured by Bruker AXS Corporation
  • the region existing at the deepest position in the plate thickness direction when observed by SEM, and the region where the Fe content exceeds 80% by mass excluding the measurement noise is judged to be a steel sheet, and the other regions are zinc-based. It was judged to be a plating layer.
  • the mechanical properties (tensile strength and spot weldability) of the hot stamped body were evaluated by the following methods.
  • Tensile strength The tensile strength of the hot stamped body is determined by preparing the No. 5 test piece described in JIS Z 2241: 2011 from an arbitrary position of the hot stamped body and following the test method described in JIS Z 2241: 2011. rice field. When the tensile strength was 1500 to 2500 MPa, it was judged to be acceptable because it had the strength generally required for the hot stamped molded product. Further, when the tensile strength is less than 1500 MPa, the strength is inferior, and when the tensile strength is more than 2500 MPa, the strength is too high and the toughness and ductility are inferior.
  • the current nugget diameter is 4 ⁇ T (t is the thickness of the test piece) and I 0, performs spot welding while further increasing the current, to determine the current welding occurs (welding current I s). Further, the welding current I s obtained was evaluated by the following criteria spot weldability. However, I 0 (kA): the current having a nugget diameter of 4 ⁇ t (t is the plate thickness of the test piece), and I a (kA): I 0 ⁇ 1.4. The cases evaluated as good and fair were judged to be acceptable because they were excellent in spot weldability, while the cases evaluated as bad were judged to be unacceptable because they were inferior in spot weldability. bottom. Good: Is > I a x 1.15 Possible (Fair): I a x 1.10 ⁇ I s ⁇ I a x 1.15 Impossible (Bad): Is ⁇ I a x 1.10
  • the tensile strength was 1500 to 2500 MPa, and the cross-sectional area ratio of the voids in the hot stamped body was reduced to 15.0% or less, and as a result. It can be seen that the spot weldability is excellent. In particular, the production No. In Nos. 1 to 26, the cross-sectional area ratio of voids was reduced to 13.0% or less in the hot stamped molded product, and the spot weldability was better.
  • the metallographic structure of the steel sheet constituting the hot-dip galvanized steel sheet is, in terms of area%, ferrite: 20 to 90%, bainite and martensite: 0 to 100. %, Pearlite: 10-80% and Bainite: 0-5%.
  • the tensile strength is out of the range of 1500 to 2500 MPa and / or the cross-sectional area ratio of the void is more than 15.0%, and the spot weldability is inferior.

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)
  • Coating With Molten Metal (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Abstract

Selon l'invention, une tôle d'acier galvanisée par immersion à chaud est pourvue d'une tôle d'acier, d'une couche limite qui est disposée sur la surface de la tôle d'acier, et d'une couche de galvanisation par immersion à chaud qui est disposée sur la surface de la couche limite. Dans une région superficielle de la tôle d'acier, la taille moyenne des grains cristallins est de 4,0 µm ou moins et l'écart type des tailles de grains cristallins est de 2,0 µm ou moins ; et dans la couche limite, la concentration en Al maximale est de à 0,30 % ou plus en masse.
PCT/JP2021/011993 2020-03-27 2021-03-23 Tôle d'acier allié galvanisée par immersion à chaud WO2021193632A1 (fr)

Priority Applications (6)

Application Number Priority Date Filing Date Title
CN202180023035.5A CN115298345A (zh) 2020-03-27 2021-03-23 热浸镀锌钢板
JP2022510548A JP7348577B2 (ja) 2020-03-27 2021-03-23 溶融亜鉛めっき鋼板
KR1020227031750A KR20220139985A (ko) 2020-03-27 2021-03-23 용융 아연 도금 강판
MX2022011603A MX2022011603A (es) 2020-03-27 2021-03-23 Lamina de acero enchapada con zinc por inmersion en caliente.
EP21776766.4A EP4130319A4 (fr) 2020-03-27 2021-03-23 Tôle d'acier allié galvanisée par immersion à chaud
US17/909,231 US20230093068A1 (en) 2020-03-27 2021-03-23 Hot-dip zinc-plated steel sheet

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2020-057273 2020-03-27
JP2020057273 2020-03-27

Publications (1)

Publication Number Publication Date
WO2021193632A1 true WO2021193632A1 (fr) 2021-09-30

Family

ID=77892199

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2021/011993 WO2021193632A1 (fr) 2020-03-27 2021-03-23 Tôle d'acier allié galvanisée par immersion à chaud

Country Status (7)

Country Link
US (1) US20230093068A1 (fr)
EP (1) EP4130319A4 (fr)
JP (1) JP7348577B2 (fr)
KR (1) KR20220139985A (fr)
CN (1) CN115298345A (fr)
MX (1) MX2022011603A (fr)
WO (1) WO2021193632A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023132350A1 (fr) * 2022-01-06 2023-07-13 日本製鉄株式会社 Tôle d'acier pour estampage à chaud ainsi que procédé de fabrication de celle-ci, et corps moulé par estampage à chaud
WO2023132349A1 (fr) * 2022-01-06 2023-07-13 日本製鉄株式会社 Tôle d'acier pour estampage à chaud ainsi que procédé de fabrication de celle-ci, et corps moulé par estampage à chaud
WO2023135962A1 (fr) * 2022-01-13 2023-07-20 日本製鉄株式会社 Tôle en acier galvanisée par immersion à chaud, et procédé de fabrication de celle-ci

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013147228A1 (fr) 2012-03-30 2013-10-03 株式会社神戸製鋼所 Procédé de fabrication pour un élément en acier moulé par pressage à chaud et élément en acier moulé par pressage à chaud
WO2014024825A1 (fr) * 2012-08-07 2014-02-13 新日鐵住金株式会社 Tôle d'acier plaquée de zinc pour moulage à chaud
WO2016031166A1 (fr) * 2014-08-28 2016-03-03 Ｊｆｅスチール株式会社 Tôle d'acier à haute résistance galvanisée par immersion dans du zinc fondu et procédé pour sa production
WO2018062381A1 (fr) * 2016-09-28 2018-04-05 Ｊｆｅスチール株式会社 Tôle d'acier et son procédé de production
WO2019003447A1 (fr) * 2017-06-30 2019-01-03 Ｊｆｅスチール株式会社 Élément pressé à chaud et son procédé de production, et tôle d'acier laminée à froid pour pressage à chaud
JP2020057273A (ja) 2018-10-03 2020-04-09 コニカミノルタ株式会社 誘導装置、制御システム、および制御プログラム

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3216886A4 (fr) * 2014-11-05 2018-04-11 Nippon Steel & Sumitomo Metal Corporation Tôle d'acier galvanisée par immersion à chaud
EP3663425B1 (fr) * 2017-07-31 2024-03-06 Nippon Steel Corporation Tôle d'acier galvanisé à chaud
CN110959047B (zh) * 2017-07-31 2022-01-04 日本制铁株式会社 热浸镀锌钢板

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013147228A1 (fr) 2012-03-30 2013-10-03 株式会社神戸製鋼所 Procédé de fabrication pour un élément en acier moulé par pressage à chaud et élément en acier moulé par pressage à chaud
WO2014024825A1 (fr) * 2012-08-07 2014-02-13 新日鐵住金株式会社 Tôle d'acier plaquée de zinc pour moulage à chaud
WO2016031166A1 (fr) * 2014-08-28 2016-03-03 Ｊｆｅスチール株式会社 Tôle d'acier à haute résistance galvanisée par immersion dans du zinc fondu et procédé pour sa production
WO2018062381A1 (fr) * 2016-09-28 2018-04-05 Ｊｆｅスチール株式会社 Tôle d'acier et son procédé de production
WO2019003447A1 (fr) * 2017-06-30 2019-01-03 Ｊｆｅスチール株式会社 Élément pressé à chaud et son procédé de production, et tôle d'acier laminée à froid pour pressage à chaud
JP2020057273A (ja) 2018-10-03 2020-04-09 コニカミノルタ株式会社 誘導装置、制御システム、および制御プログラム

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023132350A1 (fr) * 2022-01-06 2023-07-13 日本製鉄株式会社 Tôle d'acier pour estampage à chaud ainsi que procédé de fabrication de celle-ci, et corps moulé par estampage à chaud
WO2023132349A1 (fr) * 2022-01-06 2023-07-13 日本製鉄株式会社 Tôle d'acier pour estampage à chaud ainsi que procédé de fabrication de celle-ci, et corps moulé par estampage à chaud
WO2023135962A1 (fr) * 2022-01-13 2023-07-20 日本製鉄株式会社 Tôle en acier galvanisée par immersion à chaud, et procédé de fabrication de celle-ci

Also Published As

Publication number Publication date
KR20220139985A (ko) 2022-10-17
EP4130319A1 (fr) 2023-02-08
MX2022011603A (es) 2022-10-18
JP7348577B2 (ja) 2023-09-21
EP4130319A4 (fr) 2023-03-15
JPWO2021193632A1 (fr) 2021-09-30
US20230093068A1 (en) 2023-03-23
CN115298345A (zh) 2022-11-04

Similar Documents

Publication Publication Date Title
JP6264505B1 (ja) 薄鋼板およびめっき鋼板、並びに、熱延鋼板の製造方法、冷延フルハード鋼板の製造方法、薄鋼板の製造方法およびめっき鋼板の製造方法
CN101932745B (zh) 高强度钢板及其制造方法
KR102119373B1 (ko) 핫 프레스용 강판 및 그 제조 방법, 그리고 핫 프레스 부재 및 그 제조 방법
WO2021193632A1 (fr) Tôle d'acier allié galvanisée par immersion à chaud
KR20190110577A (ko) 핫 프레스 부재 및 그 제조 방법
CN115003841A (zh) 钢板、部件及它们的制造方法
KR102404647B1 (ko) 핫 스탬프 성형품 및 핫 스탬프용 강판 그리고 그들의 제조 방법
CN113544296A (zh) 热冲压成形体
CN116917524A (zh) 热冲压用钢板及热冲压成型体
CN114829652B (zh) 热压成形体
WO2021191961A1 (fr) Article moulé par estampage à chaud
WO2021191955A1 (fr) Article moulé par estampage à chaud
CN115244204A (zh) 热轧钢板
WO2022079970A1 (fr) Tôle d'acier galvanisée à chaud au trempé
KR20210124324A (ko) 핫 스탬프 성형품 및 핫 스탬프용 강판, 그리고 그것들의 제조 방법
JP7364961B2 (ja) ホットスタンプ成形体
CN113906151B (zh) 热压成型体
JP7311068B1 (ja) 亜鉛めっき鋼板および部材、ならびに、それらの製造方法
CN114945690B (zh) 钢板及其制造方法
CN113490759B (zh) 热冲压成形品及其制造方法
CN115427601A (zh) 热压用钢板以及热压成型体
CN114829651A (zh) 热压成形体
CN115398020A (zh) 热压用钢板及热压成形体
CN116997671A (zh) 热冲压用钢板及热冲压成型体
WO2023189183A1 (fr) Article formé par estampage à chaud

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: 21776766

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2022510548

Country of ref document: JP

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 20227031750

Country of ref document: KR

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 2021776766

Country of ref document: EP

ENP Entry into the national phase

Ref document number: 2021776766

Country of ref document: EP

Effective date: 20221027

NENP Non-entry into the national phase

Ref country code: DE