A process for manufacturing a coated metal strip having a metallic corrosion protection coating is provided. The process includes passing a metal strip through a molten metal bath comprising from 2 to 8 wt % aluminum, 0 to 5 wt % magnesium, up to 0.3 wt % additional elements, and a balance including zinc and inevitable impurities, to yield a molten metal coated metal strip, wiping the molten metal coated metal strip with a nozzle spraying a gas on either side of the molten metal coated metal strip and cooling the coating in a controlled manner until the coating has completely solidified, to obtain the coated metal strip. A temperature of the molten metal bath is from 350 to 700° C., and the cooling is conducted at a rate less than 15° C./s between a temperature on leaving a unit where the wiping occurs and a start of solidification of the coating, and then at a rate greater than or equal to 15° C./s between a start and an end of solidification of the coating.

The high-strength plated steel sheet of the present invention has a plated layer on the surface of a base steel sheet and contains predetermined steel components. The steel sheet includes, in the order from the interface of the base steel sheet and the plated layer towards the base steel sheet: a soft layer having a Vickers hardness that is 90% or less of the Vickers hardness at a portion t/4 of the base steel sheet, where t is a sheet thickness of the base steel sheet: and a hard layer containing martensite, bainite, and ferrite in predetermined ranges. The average depth D of the soft layer is 20 μm or greater, and the average depth d of an internal oxide layer is 4 μm or greater and smaller than D.

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%.

A method for producing a coated steel sheet having a tensile strength TS of at least 1450 MPa and a total elongation TE of at least 17% includes the successive steps of providing a cold rolled steel sheet made of a steel having a chemical composition comprising, 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%, and optionally 0%≤Nb≤0.05%, the remainder being Fe and unavoidable impurities, annealing the cold-rolled steel sheet at an annealing temperature AT higher than the Ac3 transformation point of the steel, quenching the annealed steel sheet by cooling it down to a quenching temperature QT lower than the Ms transformation point of the steel and comprised between 150° C. and 250° C., and reheating the quenched steel sheet to a partitioning temperature PT between 350° C. and 450° C. and maintaining the steel sheet at the partitioning temperature PT for a partitioning time Pt of at least 80 s, and coating the steel sheet by galvannealing, with an alloying temperature GAT comprised between 470° C. and 520° C.

A coated steel material including: a base steel, and a coating layer containing a Zn—Al—Mg alloy layer disposed on a surface of the base steel, wherein the coating layer has a predetermined chemical composition, and, in a backscattered electron image of the Zn—Al—Mg alloy layer that is obtained at a time of observing the surface of the Zn—Al—Mg alloy layer after polishing to ½ of the layer thickness, under a scanning electron microscope at a magnification of 100×, Al crystals are present, and the average value of the cumulative circumferential length of the Al crystals is 88 to 195 mm/mm.sup.2.

Provided is a steel sheet having excellent image clarity after painting, including: carbon (C): 0.001% to 0.03%, silicon (Si): 0.001% to 0.35%, manganese (Mn): 0.05% to 2.2%, phosphorus (P): 0.003% to 0.1%, sulfur (S): 0.001% or 0.025%, aluminum (Al): 0.01% to 0.1%, nitrogen (N): 0.001% to 0.007%, and a remainder of iron (Fe) and inevitable impurities. The microstructure of the steel sheet mainly is ferrite phases. An R-cube texture of a surface layer of the steel sheet is 5% or less by area %.

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 process for manufacturing corrosion resistant metal components is disclosed. The process comprises abrasive blasting of a silicon-containing steel substrate followed by hot dip galvanizing, a second abrasive blasting process, treating with a mineral acid, and coating with a polymeric coating. The resulting corrosion resistance is enhanced.

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.

Zn alloy plated steel material having excellent weldability and processed-part corrosion resistance and a method for production of Zn alloy plated steel material are provided. In the Zn alloy plated steel material comprising base steel material and a Zn alloy plating layer, the Zn alloy plating layer includes, by wt %, Al: 0.1-5.0%, Mg: 0.1-5.0%, as well as a remainder of Zn and inevitable impurities. The Zn alloy plated steel material includes a lower interface layer and an upper interface layer between the base steel material and the Zn alloy plating layer, wherein the lower interface layer is formed on the base steel material and has a dense structure, and the upper interface layer is formed on the lower interface layer and has a network-type or island-type structure.