COLD ROLLED RECOVERY ANNEALED MILD STEEL AND PROCESS FOR MANUFACTURE THEREOF

• Main Authors: EHRHARDT BERTRAM WILHELM, BEVANS STANLEY WAYNE, BOGGS ROGER DALE, SAMUEL CHRIS JOHN PAUL
• Format: Patent
• Language: English
• Published: 17.04.2014
• Subjects: CHEMISTRY; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; PUNCHING METAL; ROLLING OF METAL; TRANSPORTING

A high strength mild steel alloy is provided. In addition, a process for making the high strength steel alloy is also provided. The process includes providing a mild steel alloy with a chemical composition in weight percent within a range of 0.12-0.25 carbon, 0.30-1.70 manganese, 0.50 max silicon, 0.10 max chromium, 0.01 max niobium, 0.035 max titanium, 0.01 vanadium, 0.10 max molybdenum, 0.10 max nickel, 0.015 max sulfur, 0.025 max phosphorus, 0.012 max nitrogen, 0.003 max boron, and 0.015-0.065 aluminum. Hot rolled steel strip with a thickness of less than 10 millimeters is cold rolled to produce a cold rolled steel sheet that has a thickness that is less than 50% of the hot rolled steel strip thickness which is subsequently recovery annealed to provide sheet material having a yield strength greater than 550 megapascals (MPa) and a percent elongation to failure greater than 3.5%.