ArcelorMittal S.A.
Hot rolled steel sheet with high hole expansion ratio and manufacturing process thereof

Abstract:

A hot rolled steel sheet having a chemical composition including, in weight %: 0.15%.ltoreq.C.ltoreq.0.20%, 0.50%.ltoreq.Mn.ltoreq.2.00%, 0.25%.ltoreq.Si.ltoreq.1.25%, 0.10%.ltoreq.Al.ltoreq.1.00%, with 1.00%.ltoreq.(Al+Si).ltoreq.2.00%, 0.001%.ltoreq.Cr.ltoreq.0.250%, P.ltoreq.0.02%, S.ltoreq.0.005%, N.ltoreq.0.008%, and optionally one or more elements among: 0.005%.ltoreq.Mo.ltoreq.0.250%, 0.005%.ltoreq.V.ltoreq.0.250%, 0.0001%.ltoreq.Ca.ltoreq.0.003% and 0.001%.ltoreq.Ti.ltoreq.0.025%, the remainder being Fe and unavoidable impurities, and wherein the microstructure includes in surface fraction, ferrite and bainite, the sum of which being greater than 5% and strictly lower than 20%, the remainder consisting of tempered martensite.