ArcelorMittal S.A.
METHOD FOR FABRICATING STEEL SHEET FOR PRESS HARDENING, AND PARTS OBTAINED BY THIS METHOD

Abstract:

The present invention provides fabrication methods for cold rolled, precoated and press hardened steel sheets, for which the chemical composition includes, with contents expressed by weight, 0.24%.ltoreq.C.ltoreq.0.38%, 0.40%.ltoreq.Mn.ltoreq.3%, 0.10%.ltoreq.Si.ltoreq.0.70%, 0.015%.ltoreq.Al.ltoreq.0.070%, 0%.ltoreq.Cr.ltoreq.2%, 0.25%.ltoreq.Ni.ltoreq.2%, 0.015%.ltoreq.Ti.ltoreq.0.10%, 0%.ltoreq.Nb.ltoreq.0.060%, 0.0005%.ltoreq.B.ltoreq.0.0040%, 0.003%.ltoreq.N.ltoreq.0.010%, 0.0001%.ltoreq.S.ltoreq.0.005%, 0.0001%.ltoreq.P.ltoreq.0.025%, it being understood that the titanium and nitrogen content satisfy: Ti/N>3.42, and that the carbon, manganese, chromium and silicon content satisfy: 2.6C+Mn/5.3+Cr/13+Si/15.gtoreq.1.1%, with the chemical composition optionally including one or more of the following elements: 0.05%.ltoreq.Mo.ltoreq.0.65%, 0.001%.ltoreq.W.ltoreq.0.30%, 0.0005%.ltoreq.Ca.ltoreq.0.005%, with the remainder made up of iron and inevitable impurities coming from preparation.