A plated steel includes: a steel; and a plating layer that is provided on a surface of the steel, in which the plating layer includes, by mass %, Al: 5.00% to 35.00%, Mg: 2.50% to 13.00%. Fe: 5.00% to 40.00%, Si: 0% to 2.00%, Ca: 0% to 2.00%, and a remainder of Zn and impurities, and in a cross section of the plating layer, the area fraction of a Zn solid-solution Fe.sub.2Al.sub.5 phase in which 5% or more of Zn is solid-soluted is 10% to 60% and the area fraction of a MgZn.sub.2 phase is 10% to 90%.

The plated steel material is a plated steel material including a steel material and a plating layer provided on the surface of the steel material, wherein the plating layer has a predetermined average chemical composition, when the amount of Mg is % Mg and the amount of Al is % Al, % Mg/% Al is 0.80 or more, and a metal structure in a total field of view of 25,000 μm.sup.2 in a vertical cross section which is a cross section in a thickness direction of the plating layer includes 10 to 40 area % of a MgZn.sub.2 phase, 10 to 30 area % of an Al—Zn phase with a Zn content of 10% or more, 0 to 15 area % of an Al phase with a Zn content of less than 10%, and 25 area % or more of an Al/MgZn.sub.2/Zn ternary eutectic structure.

A method for forming a zinc-plated steel plate or steel belt having good corrosion resistance, comprising the following steps: 1) conveying the steel plate or steel belt into a heating furnace higher than Ac.sub.3, austenitizing the steel plate or steel belt, and keeping the temperature for 1-7 minutes; 2) before the steel plate or steel belt leaves the heating furnace and enters a forming mold, applying different cooling manners according to different plated thicknesses, wherein when the single-sided weight of the plating is less than or equal to 50 g/m.sup.2, only air cooling is required before transferring to the forming mold, when the single-sided weight of the plating is greater than 50 g/m.sup.2, aerial fog or water mist precooling is performed before transferring to the forming mold, and the steel plate is cooled to be below 700° C. at a cooling sped greater than 30° C./s; and 3) rapidly transferring the steel plate or steel belt to the mold for hot stamping forming, wherein a transferring duration does not exceed 1 minute, and the temperature of the hot stamping forming is controlled between 400-800° C. The tensile strength of the steel plate or steel belt after hot stamping is greater than 1,450 MPa, and substrate cracks caused by local press and LME in an element are avoided.

A high-strength steel sheet contains, in mass %, C: 0.07 to 0.14%, Si: 0.65 to 1.65%, Mn: 1.8 to 2.6%, P: 0.05% or less, S: 0.005% or less, Al: 0.08% or less, N: 0.0060% or less, Ti: 0.005 to 0.030%, B: 0.0002 to 0.0030%, and either or both of Cr: 0.01 to 0.40% and Mo: 0.01 to 0.50% and satisfies the expression (1); where: an average grain size of a ferrite phase is 1.5 μm or less; an area ratio of the ferrite phase is 2% or more and 15% or less; an area ratio of a tempered martensite phase is 75% or more and 96% or less; and a total length per unit area of an interface between an untempered martensite phase and the ferrite phase and an interface between the untempered martensite phase and the tempered martensite phase is 6.3×10.sup.8 μm/m.sup.2 to 5.0×10.sup.11 μm/m.sup.2.

Provided is a galvanized steel sheet plated by vacuum deposition and, more specifically, to a galvanized steel sheet having excellent hardness and galling resistance, and a method for manufacturing same. The zinc coated steel sheet includes: a base steel sheet; and a zinc coated layer formed on the base steel sheet. The zinc coated layer is formed of a columnar structure, and a content of Mn included in the zinc coated layer is 0.1 to 0.4 wt %.

A steel sheet having excellent fatigue resistance as a material for automobile parts and a TS of 590 MPa or more, and a method for producing the same. The steel sheet has a composition comprising, by mass %, C: 0.04% or more and 0.15% or less, Si: 0.3% or less, Mn: 1.0% or more and 2.6% or less, P: 0.1% or less, S: 0.01% or less, Al: 0.01% or more and 0.1% or less, N: 0.015% or less, one or two of Ti and Nb: 0.01% or more and 0.2% or less in a total, and the balance being Fe and unavoidable impurities. The steel sheet has 50% or more of ferrite and 10% or more and 50% or less of martensite in terms of an area ratio, and a microstructure in which a standard deviation of nano-hardness is 1.50 GPa or less and tensile strength of 590 MPa or more.

The invention relates to a biodegradable implant comprising a surface coated magnesium alloy or zinc alloy product, whereby the coating layer comprises oxides and/or phosphates of from rare-earth elements, Mg, Ca, Zn, Zr, Cu, Fe, Sr, Li, Mn or Ag wherein the coating is preferably generated by plasma electrolytically oxidation (PEO). The invention further comprises a method for preparing the coated magnesium or zinc alloy product of the implant.

The invention relates to a biodegradable implant comprising a surface coated magnesium alloy or zinc alloy product, whereby the coating layer comprises oxides and/or phosphates of from rare-earth elements, Mg, Ca, Zn, Zr, Cu, Fe, Sr, Li, Mn or Ag wherein the coating is preferably generated by plasma electrolytically oxidation (PEO). The invention further comprises a method for preparing the coated magnesium or zinc alloy product of the implant.

Provided is a galvanized steel sheet having excellent plating adhesion, having a plated layer with improved friction characteristics by means of a predetermined level of Fe elution, and having excellent corrosion resistance; and a manufacturing method therefor.

A high-strength steel sheet having a microstructure represented by, in area %, martensite: 5% or more; ferrite: 20% or more; and pearlite: 5% or less. A ratio of the number of bulging type martensite grains to the number of martensite grains on grain boundary triple points of a matrix is 70% or more, wherein: the bulging type martensite grain is on one of the grain boundary triple points of the matrix; and at least one of grain boundaries of the bulging type martensite grain, the grain boundaries connecting two adjacent grain boundary triple points of the bulging type martensite grain and grains of the matrix, has a convex curvature to an outer side with respect to line segments connecting the two adjacent grain boundary triple points. An area ratio VM/A0 is 1.0 or more.