ArcelorMittal S.A.
HOT ROLLED STEEL AND A METHOD OF MANUFACTURING THEREOF

Abstract:

A hot rolled steel having a composition including the following elements, expressed in percentage by weight: 15%.ltoreq.Nickel.ltoreq.25% 6%.ltoreq.Cobalt.ltoreq.12% 2%.ltoreq.Molybdenum.ltoreq.6% 0.1%.ltoreq.Titanium.ltoreq.1% 0.0001%.ltoreq.Carbon.ltoreq.0.03% 0.002%.ltoreq.Phosphorus.ltoreq.0.02% 0%.ltoreq.Sulfur.ltoreq.0.005%. 0 %.ltoreq.Nitrogen.ltoreq.0.01% and can contain one or more of the following optional elements 0%.ltoreq.Aluminum.ltoreq.0.1% 0%.ltoreq.Niobium.ltoreq.0.1% 0%.ltoreq.Vanadium.ltoreq.0.3% 0%.ltoreq.Copper.ltoreq.0.5% 0%.ltoreq.Chromium.ltoreq.0.5% the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of said steel sheet comprising in area fraction, 20% to 40% Tempered Martensite, at least 60% of Reverted Austenite and inter-metallic compounds of Molybdenum, Titanium and Nickel.