Patent ID: 6419762
Filing Date: 2002-07-16
Classification: C21D

Abstract:
A railroad rail of a steel alloy having a pearlitic microstructure, which rail comprises a rail head, a rail web and a rail base and has a weight of 30 to 100 kg/m, wherein the rail is formed of a steel alloy having a chemical composition in weight % ofcarbon (C)0.4 to 1.0silicon (Si)0.1 to 1.2manganese (Mn)0.5 to 3.5chromium (Cr)up to 1.5,optionally other alloy elements below 1 weight %, the rest being iron (Fe) and impurities occurring in the manufacturing process, wherein at least the rail head has a portion of fine pearlitic grain microstructure and a hardness between 340 HB and 425 HB down to a sufficient depth from the top surface, the remaining rail portions have a hardness which is lower than said portion of fine pearlitic grain microstructure , wherein an arrangement and a size and extension, respectively, of the portion of fine pearlitic grain microstructure and increased hardness in the rail cross section is even along the entire length of the rail, and wherein the rail base has a hardness of 280 to 320 HB in peripheral areas thereof and an increased hardness of 300 to 350 HB in a central bottom portion, opposite the rail web.