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 m.

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 m.

The present invention forms part of the development of new iron-based alloys, particularly a steel with improved mechanical, thermal and physico-chemical (corrosion) properties. The invention relates more specifically to a steel material with a new microstructure, characterized by a triple hierarchical structuring in which appears a network of internal nanometric sub-cells capable of improving the properties and performance of steels.

The present invention forms part of the development of new iron-based alloys, particularly a steel with improved mechanical, thermal and physico-chemical (corrosion) properties. The invention relates more specifically to a steel material with a new microstructure, characterized by a triple hierarchical structuring in which appears a network of internal nanometric sub-cells capable of improving the properties and performance of steels.

A hollow wind turbine main shaft and a profiling forging process and a use thereof are provided. The profiling forging process includes: step S1: smelting alloying elements according to a formula to obtain a melt, casting the melt to obtain an ingot, and hot-feeding the ingot; step S2: reheating the ingot hot-fed in the step S1, followed by primary drawing-out, primary upsetting, secondary drawing-out, and secondary upsetting to obtain a forged ingot; step S3: reheating the forged ingot, followed by punching to obtain a punched forging; step S4: reheating the punched forging, and performing drawing-out and rounding on a shaft body of the punched forging to obtain a finished forging; and step S5: placing the finished forging into a thermal insulation barrel for slow cooling, and air-cooling the finished forging to a room temperature to obtain the hollow wind turbine main shaft.

A hollow wind turbine main shaft and a profiling forging process and a use thereof are provided. The profiling forging process includes: step S1: smelting alloying elements according to a formula to obtain a melt, casting the melt to obtain an ingot, and hot-feeding the ingot; step S2: reheating the ingot hot-fed in the step S1, followed by primary drawing-out, primary upsetting, secondary drawing-out, and secondary upsetting to obtain a forged ingot; step S3: reheating the forged ingot, followed by punching to obtain a punched forging; step S4: reheating the punched forging, and performing drawing-out and rounding on a shaft body of the punched forging to obtain a finished forging; and step S5: placing the finished forging into a thermal insulation barrel for slow cooling, and air-cooling the finished forging to a room temperature to obtain the hollow wind turbine main shaft.