ArcelorMittal S.A.
COLD ROLLED AND HEAT TREATED STEEL SHEET, METHOD OF PRODUCTION THEREOF AND USE OF SUCH STEEL TO PRODUCE VEHICLE PARTS

Abstract:

A cold rolled and heat treated steel sheet having a composition containing the following elements, expressed in percent by weight: 0.15%.ltoreq.carbon.ltoreq.0.6%; 4%.ltoreq.manganese.ltoreq.20%; 5%.ltoreq.aluminum.ltoreq.15%; 0.ltoreq.silicon.ltoreq.2%; aluminium+silicon.gtoreq.6.5%; and possibly one or more of the following elements: 0.01%.ltoreq.niobium.ltoreq.0.3%; 0.01%.ltoreq.titanium.ltoreq.0.2%; 0.01%.ltoreq.vanadium.ltoreq.0.6%; 0.01%.ltoreq.copper.ltoreq.2.0%; 0.01%.ltoreq.nickel.ltoreq.2.0%; cerium.ltoreq.0.1%; boron.ltoreq.0.01%; magnesium.ltoreq.0.05%; zirconium.ltoreq.0.05%; molybdenum.ltoreq.2.0%; tantalum.ltoreq.2.0%; tungsten.ltoreq.2.0%; the remainder being composed of iron and unavoidable impurities caused by elaboration, wherein the microstructure of said steel sheet contains in area fraction, 10 to 50% of austenite, the reminder being regular ferrite and ordered ferrite of D03 structure. A manufacturing method and use of the steel sheet for making vehicle parts is also described.