ArcelorMittal S.A.
Method of production of a cold rolled and heat treated steel sheet to produce vehicle parts

Abstract:

A method of production of a cold rolled and heat treated steel sheet has the following steps: providing a cold rolled steel sheet with a composition including 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%, a remainder being composed of iron and unavoidable impurities caused by elaboration; heating said cold rolled steel sheet up to a soaking temperature between 800 and 950.degree. C. during less than 600 seconds, then cooling the sheet down to a temperature in a range of 600.degree. C. to room temperature, reheating the steel sheet to a soaking temperature of 150.degree. C. to 600.degree. C. during 10 s to 250 h, then cooling the sheet.