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 m.

A coated metallic substrate including at least a first coating consisting of aluminum is provided. The first coating has a thickness between 1.0 and 4.5 m and is directly topped by a second coating based on zinc, such second coating having a thickness between 1.5 and 9.0 m. The thickness ratio of the first coating with respect to the second coating is between 0.2 and 1.2.

A coated metallic substrate including at least a first coating consisting of aluminum is provided. The first coating has a thickness between 1.0 and 4.5 m and is directly topped by a second coating based on zinc, such second coating having a thickness between 1.5 and 9.0 m. The thickness ratio of the first coating with respect to the second coating is between 0.2 and 1.2.

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.