HEAT TREATMENT FOR STEEL RAIL EXCELLENT IN FALLING LOAD-RESISTING CHARACTERISTIC

摘要

PURPOSE:To carry out the heat treatment of a steel rail excellent in falling weight-resisting characteristic by applying specific accelerated cooling to a rail foot to make the rail foot high-hardness while subjecting a railhead to accelerated cooling from an austenitic region after rail rolling. CONSTITUTION:While applying accelerated cooling to a railhead from an austenitic region after rail rolling, a rail foot is subjected to accelerated cooling through a temperature range from 800 to 450 deg.C at 1-5 deg.C/sec cooling rate. This accelerated cooling is carried out by using a gaseous or liquefied-gaseous cooling medium. By this cooling, the average pearlite hardness of the rail foot is regulated to =HB320. By the above heat treatment, the falling weight-resisting characteristic of the steel rail can be improved, and a steel rail suitably used for steel rail for high-load railroad in cold districts can be obtained.