ArcelorMittal S.A.
A COLD ROLLED MARTENSITIC STEEL AND A METHOD OF MARTENSITIC STEEL THEREOF

Abstract:

A cold rolled martensitic steel sheet including the following elements, expressed in percentage by weight: 0.1%.ltoreq.C.ltoreq.0.2%; 1.5%.ltoreq.Mn.ltoreq.2.5%; 0.1%.ltoreq.Si.ltoreq.0.25%; 0.1%.ltoreq.Cr.ltoreq.1%; 0.01%.ltoreq.Al.ltoreq.0.1%; 0.001%.ltoreq.Ti.ltoreq.0.1%; 0%.ltoreq.S.ltoreq.0.09%; 0%.ltoreq.P.ltoreq.0.09%; 0%.ltoreq.N.ltoreq.0.09%; and can contain one or more of the following optional elements 0%.ltoreq.Ni.ltoreq.1%; 0%.ltoreq.Cu.ltoreq.1%; 0%.ltoreq.Mo.ltoreq.0.4%; 0%.ltoreq.Nb.ltoreq.0.1%; 0%.ltoreq.V.ltoreq.0.1%; 0%.ltoreq.B.ltoreq.0.05%; 0%.ltoreq.Sn.ltoreq.0.1%; 0%.ltoreq.Pb.ltoreq.0.1%; 0%.ltoreq.Sb.ltoreq.0.1%; 0.001%.ltoreq.Ca.ltoreq.0.01%; the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel including, by area percentage, at least 95% of martensite, a cumulated amount of ferrite and bainite between 1% and 5%, and an optional amount of residual austenite between 0% and 2%.