PROCESS FOR MANUFACTURING HIGH-STRENGTH BAINITIC STEEL RAILS WITH EXCELLENT ROLLING-CONTACT FATIGUE RESISTANCE

摘要

A process for manufacturing high-strength bainitic steelrails with an excellent rolling-contact fatigue resistancecomprising the steps of hot rolling steel containing 0.15 %to 0.45 % carbon, 0.15 % to 2.00 % silicon, 0.30 % to 2.00 %manganese, 0.50 % to 3.00 % chromium, and at least oneelement selected from a group of molybdenum, nickel, copper,niobium, vanadium, titanium and boron, subjecting thehot-rolled rail to an accelerated cooling from the austeniteregion to a temperature between 500° to 300° C, at which theaccelerated cooling is stopped, at a rate of 1° to 10° C persecond, and then further cooling the rail to a lowertemperature by natural or controlled cooling. The obtained railexhibits a hardness of Hv 300 to 400 in the center of therail head surface of the head and not lower than Hv 350 inthe gage corner, and the hardness of the gage corner ishigher than that of the center of the rail head surface byHv 30 or more.