ArcelorMittal S.A.
A METHOD FOR THE MANUFACTURE OF A COATED STEEL SHEET

Abstract:

Method for the manufacture of a coated steel sheet including the following successive steps A. the provision of an annealed steel sheet having the following chemical composition in weight: 0.10<C<0.40%, 1.5<Mn<3.0%, 0.7<Si<2.0%, 0.05<Al<1.0%, 0.75<(Si+Al)<3.0%, and on a purely optional basis, one or more elements such as Nb.ltoreq.0.5%, B.ltoreq.0.005%, Cr.ltoreq.1.0%, Mo.ltoreq.0.50%, Ni.ltoreq.1.0%, Ti.ltoreq.0.5%, the remainder of the composition making up of iron and inevitable impurities resulting from the elaboration, such steel sheet being annealed at a temperature between 600 to 1200.degree. C., B. the coating of the steel sheet obtained in step A) with a first coating including nickel, such first coating not including iron, and having a thickness equal or above 0.5 .mu.m and C. the coating of the steel sheet obtained in step B) with a second coating based on zinc. A steel sheet, a spot welded joint and further uses of the steel sheet are also provided.