ArcelorMittal S.A.
HIGH STRENGTH HOT ROLLED STEEL HAVING EXCELLENT SCALE ADHESIVNESS AND A METHOD OF MANUFACTURING THE SAME

Abstract:

A hot rolled steel product having a composition including in percentage by weight: 0.06%.ltoreq.C.ltoreq.0.18%, 0.01%.ltoreq.Ni.ltoreq.0.6%, 0.001%.ltoreq.Cu.ltoreq.2%, 0.001%.ltoreq.Cr.ltoreq.2%, 0.001%.ltoreq.Si.ltoreq.0.8%, 0%.ltoreq.N.ltoreq.0.008%, 0%.ltoreq.P.ltoreq.0.03%, 0%.ltoreq.S.ltoreq.0.03%, 0.001%.ltoreq.Mo.ltoreq.0.5%, 0.001%.ltoreq.Nb.ltoreq.0.1%, 0.001%.ltoreq.V.ltoreq.0.5%, 0.001%.ltoreq.Ti.ltoreq.0.1% and one or more following optional elements 0.2%.ltoreq.Mn.ltoreq.2%, 0.005%.ltoreq.Al.ltoreq.0.1%, 0%.ltoreq.B.ltoreq.0.003%, 0%.ltoreq.Ca.ltoreq.0.01%, 0%.ltoreq.Mg.ltoreq.0.010% the remainder composition being composed of iron and unavoidable impurities caused by processing, such product having a tertiary scale layer including, in area fraction, a total amount of at least 50% of magnetite and ferrite wherein ferrite is at least 25%, 0% to 50% of wustite, and 0% to 10% of hematite, such scale layer having a thickness between 5 microns and 40 microns.