A press hardening method including the following steps: A. the provision of a steel sheet for heat treatment being optionally coated with a zinc- or aluminum-based pre-coating, B. the flexible rolling of the steel sheet in the rolling direction so as to obtain a steel sheet having a variable thickness, C. the cutting of the rolled steel sheet to obtain a tailored rolled blank, D. the deposition of a hydrogen barrier pre-coating over a thickness from 10 to 550 nm, E. the heat treatment of the tailored rolled blank to obtain a fully austenitic microstructure in the steel, F. the transfer of the tailored rolled blank into a press tool, G. the hot-forming of the tailored rolled blank to obtain a part having a variable thickness,H. the cooling of the part having a variable thickness obtained at step G).

The present invention provides a method for manufacturing more beautiful black coated steel sheets by uniformly blackening the coating layer. Specifically, the present invention provides a method for manufacturing black coated steel sheets, which brings Zn—Al—Mg alloy coated steel sheets (1) into contact with steam in a closed container (10), wherein said closed container (10) can maintain a predefined internal pressure through variable control of the amount of steam flowing into said closed container (10) and/or the amount of steam flowing out of said closed container (10), and in said closed container (10) that can maintain said predefined pressure, said Zn—Al—Mg alloy coated steel sheets (1) have contact with the steam introduced into said closed container (10).

Provided is a Zn—Al—Mg-based alloy-plated steel material that can be used in automobiles and home appliances and the like and, more particularly, to a Zn—Al—Mg-based alloy-plated steel material that can suppress the generation of cracks in a plating layer that are generated during processing.

A plated steel sheet having excellent post-coating corrosion resistance 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% to 2.00%, and a remainder consisting of Zn and impurities, and in a cross section of the plating layer, the area fraction of a Fe.sub.2Al.sub.5 phase is 5.0% to 60.0%, the area fraction of an eutectic structure of Zn and MgZn.sub.2 is 10.0% to 80.0%, the area fraction of a massive MgZn.sub.2 phase is 5.0% to 40.0%, and the area fraction of a remainder is 10.0% or less.

A steel part includes a steel sheet substrate and a coating on at least one surface of the steel sheet substrate. The coating includes between 0.2 and 0.7% by weight of Al, with a remainder of the metal coating being Zn and inevitable impurities. The steel sheet substrate and the coating have at least one deformation. An outer surface of the coating has a waviness Wa.sub.0.8 of less than or equal to 0.43 μm.

A hot pressed member disclosed herein includes: a base steel sheet; a Fe—Zn—Al—Mg-based alloy coated layer containing an α-Fe phase and a Γ phase and formed on at least one surface of the base steel sheet; and an oxide layer containing Zn, Al, and Mg and formed on the Fe—Zn—Al—Mg-based alloy coated layer, in which a ratio of I.sub.Γ/I.sub.α is 0.5 or less when measured by X-ray diffraction using a Co-Kα (wavelength: 1.79021 Å) radiation source at an incident angle of 25°, where IF is an intensity of a diffraction peak of (411) plane of the Γ phase present in an angular range of 41.5°≤2θ≤43.0° and I.sub.α is an intensity of a diffraction peak of (110) plane of the α-Fe phase present in an angular range of 51.0°≤2θ≤52.0°, and a sum of Al and Mg concentrations in the oxide layer is 28 atomic % or more.

An embodiment of the present disclosure provides a hot dip alloy coated steel material having high corrosion resistance, the hot dip alloy coated steel material including: a base steel sheet; and a hot dip alloy coating layer formed on the base steel sheet, wherein the hot dip alloy coating layer includes, by wt %, Al: from greater than 8% to 25%, Mg: from greater than 4% to 12%, and a balance of Zn and other inevitable impurities, wherein a surface of the hot dip alloy coating layer has a surface X-ray diffraction intensity satisfying Condition 1 below: [Condition 1] 2000 cps≤X-ray diffraction intensity≤20000 cps where the X-ray diffraction intensity refers to M−N, M refers to a greatest peak intensity within a 2θ range of 20.00° to lower than 21°, and N refers to a peak intensity at 2θ=20.00°.

The invention relates to a method for coating a steel sheet or steel strip to which an aluminium-based coating is applied in a dip-coating process and the surface of the coating is freed of a naturally occurring aluminium oxide layer. In order to provide a low-cost method for coating steel sheets or steel strips that makes the steel sheets or steel strips outstandingly suitable for the production of components by means of press hardening and for the further processing thereof, it is proposed that transition metals or transition metal compounds are subsequently deposited on the freed surface of the coating to form a top layer. The invention also relates to a method for producing press-hardened components from the aforementioned steel sheets or steel strips with an aluminium-based coating.

A plated steel sheet for hot stamping including a base metal and a galvanized layer that is formed on a surface of the base metal, wherein the galvanized layer includes a galvannealed layer, a solidified zinc layer, and an oxide layer containing Al, in this order from the base metal, and a proportion of a content of Zn (g/m.sup.2) in the solidified zinc layer to a content of Zn (g/m.sup.2) in the galvanized layer is 10 to 95%.

A coated metal sheet includes a steel substrate and a coating on at least one surface of the steel substrate. The coating includes between 0.2 and 0.7% by weight of Al, with a remainder of the metal coating being Zn and inevitable impurities. The coated metal sheet was subjected to a skin pass operation after coating. An outer surface of the metal coating has a waviness Wa.sub.0.8 of less than or equal to 0.55 μm.