ArcelorMittal S.A.
METHOD FOR MANUFACTURING A RAIL AND CORRESPONDING RAIL

Abstract:

A method for manufacturing a rail includes casting a steel to obtain a semi-product. The steel has a composition comprising 0.20%.ltoreq.C.ltoreq.0.60%, 1.0%.ltoreq.Si.ltoreq.2.0%, 0.60%.ltoreq.Mn.ltoreq.1.60% and 0.5.ltoreq.Cr.ltoreq.2.2%, optionally 0.01%.ltoreq.Mo.ltoreq.0.3%, 0.01%.ltoreq.V.ltoreq.0.30%; the remainder being Fe and impurities. The method also includes hot rolling the semi-product into a hot rolled semi-product having the shape of the rail and comprising a head, with a final rolling temperature T.sub.FRT higher than Ar3; and cooling the head to a cooling stop temperature T.sub.CS between 200.degree. C. and 520.degree. C. The temperature of the head over time is comprised between a upper boundary having the coordinates defined by A1 (0 second, 780.degree. C.), B1 (50 seconds, 600.degree. C.), and C1 (110 seconds, 520.degree. C.) and a lower boundary having the coordinates defined by A2 (0 second, 675.degree. C.), B2 (50 seconds, 510.degree. C.), and C2 (110 seconds, 300.degree. C.). The method also includes maintaining the head in a temperature range comprised between 300.degree. C. and 520.degree. C. during a holding time t.sub.hold of at least 12 minutes, and; cooling down the hot rolled semi-product to room temperature to obtain the rail.