Disclosed is a hot-dip Al—Zn alloy coated steel sheet having excellent anti-corrosion property after coating, and a method for producing the same. In the disclosure, the hot-dip Al—Zn alloy coated steel sheet has a hot-dip coating layer containing by mass %, Al: 25% to 90%, and at least one of Sn: 0.01% to 2.0%, In: 0.01% to 10%, and Bi: 0.01% to 2.0%.

A plated steel sheet includes: a steel sheet; and a plating layer that is formed on at least a part of a surface of the steel sheet, in which a chemical composition of the plating layer includes, by mass %, Al: more than 5.00% and 35.00% or less, Mg: 3.00% to 15.00%, Si: 0% to 2.00%, Ca: 0% to 2.00%, and a remainder of Zn and impurities, in which in a cross section of the plating layer in a thickness direction, the area ratio of a lamellar structure in which an (Al—Zn) phase and a MgZn.sub.2 phase are arranged in layers is 10% to 90%, a lamellar spacing of the lamellar structure is 2.5 μm or less, and the area ratio of an (Al—Zn) dendrite is 35% or less.

A plated steel sheet having excellent chemical convertibility 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 35.00%, Si: 0% to 2.00%, Ca: 0.03% to 2.00%, and a remainder consisting of Zn and impurities, and in a surface of the plating layer, the area fraction of a Fe—Al phase is 0% to 30%, the area fraction of a rod-like lamellar structure of Zn and MgZn.sub.2 is 5% to 90%, the area fraction of a massive MgZn.sub.2 phase is 10% to 70%, and the area fraction of a remainder is 10% or less.

A method is for producing a high strength coated steel sheet having an improved ductility and an improved formability, and a chemical composition containing: 0.13%≤C≤0.22%, 1.9%≤Si≤2.3%, 2.4%≤Mn≤3%, Al≤0.5%, Ti≤0.05%, Nb≤0.05%, the remainder being Fe and unavoidable impurities. The sheet is annealed at temperature TA higher than Ac3 but less than 1000° C. for a time of more than 30 s, quenched by cooling to a quenching temperature QT between 200° C. and 280° C. in order to obtain a structure consisting of austenite and at least 50% of martensite, the austenite content being such that the final structure can contain between 3% and 15% of residual austenite and between 85% and 97% of the sum of martensite and bainite, without ferrite, heated up to a partitioning temperature PT between 430° C. and 490° C. and maintained at this temperature for a time Pt between 10 s and 100 s, hot dip coated and cooled to the room temperature.

A plated steel sheet having excellent chemical convertibility 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 35.00%, Si: 0% to 2.00%, Ca: 0.03% to 2.00%, and a remainder consisting of Zn and impurities, and in a surface of the plating layer, the area fraction of a Fe—Al phase is 0% to 30%, the area fraction of a rod-like lamellar structure of Zn and MgZn.sub.2 is 5% to 90%, the area fraction of a massive MgZn.sub.2 phase is 10% to 70%, and the area fraction of a remainder is 10% or less.

A metallic component includes a core formed of steel. A zinc alloy layer is disposed on the core. The zinc alloy layer is formed of zinc and a very small amount of aluminum, such as 0.14 weight percent or less. A method of creating a component includes providing a steel core, providing a zinc bath consisting of essentially of 0.01 to 0.14 weight percent aluminum, and hot dipping the steel core into the zinc bath to form a zinc coating on the steel core resulting in a zinc-coated steel component. The aluminum may be provided in even lower contents, such as less than 0.08 weight percent, or even less than 0.05 weight percent. The zinc-coated steel component may then be spot welded to another component without first annealing the zinc-coated component. Rather, heat treating is performed locally at the weld joint by the welding procedure alone.

A method for producing a coated steel sheet having a tensile strength of at least 1450 MPa and a total elongation of at least 17% is provided. The method includes providing a cold rolled steel sheet having a chemical composition in weight %: 0.34%≤C≤0.45%, 1.50%≤Mn≤2.30%, 1.50%≤Si≤2.40%, 0%<Cr≤0.7%, 0%≤Mo≤0.3%, 0.10%≤Al≤0.7%, optionally 0%≤Nb≤0.05%, and a remainder of Fe and unavoidable impurities. The sheet is annealed at an annealing temperature higher than the Ac3 transformation point of the steel, quenched to a quenching temperature lower than the Ms transformation point of the steel and between 150° C. and 250° C., reheated to a partitioning temperature between 350° C. and 450° C., maintained at the partitioning temperature for at least 80 s, then coated by galvannealing, with an alloying temperature between 470° C. and 520° C. A steel sheet is also provided.

Provided is a plated steel sheet applicable for various purposes as in construction materials, household electric appliances, automobiles, etc. and, more particularly, to a hot dip plated steel sheet having excellent corrosion resistance and workability and a manufacturing method therefor.

A high-frequency heating method for a hot stamping process includes: a first heating step of high-frequency heating a steel sheet, which has an aluminum (Al) coating layer formed on an iron (Fe)-based base material, to a first target temperature at a first heating rate; a second heating step of melting the coating layer by high-frequency heating the steel sheet, which has passed through the first heating step, to a second target temperature at a second heating rate, wherein the second heating rate is lower than the first heating rate; and a third heating step of high-frequency heating the steel sheet, which has passed through the second heating step, to a third target temperature at a third heating rate, wherein the third heating rate is lower than the second heating rate. A compound is formed by a reaction between a material of the coating layer and a material of the base material in the second heating step. Therefore, the coating layer is not shifted even when high-frequency heating is performed at a temperature equal to or higher than the melting point of the coating layer.

A Sn-plated steel sheet according to the present invention includes a steel sheet, a Sn-plated layer that is provided on at least one surface of the steel sheet, and a film that is provided on a surface of the Sn-plated layer and includes zirconium oxide and tin oxide, in which an amount of the zirconium oxide in the film is 0.2 mg/m.sup.2 to 50 mg/m.sup.2 in terms of metal Zr amount, in a depth direction analysis by X-ray photoelectron spectroscopy, a depth position A at which an element concentration of Zr present as the zirconium oxide is maximum is positioned closer to a surface of the film than a depth position B at which an element concentration of Sn present as the tin oxide is maximum, and a distance between the depth position A and the depth position B in a depth direction is 0.5 nm or more.