| 摘要 |
PROBLEM TO BE SOLVED: To stably provide a rail which stably shows enhanced surface damage resistance in a head part, by forming a pearlitic structure having high hardness in the rail that is used for a heavy load railroad and has the pearlitic structure containing high carbon. SOLUTION: When manufacturing the rail by using a steel slab for hot-rolling, which comprises, by mass, 0.85-1.40% C, 0.05-0.50% V, 0.0060-0.0300% N, 0.10-2.00% Si, 0.10-2.00% Mn and the balance Fe with unavoidable impurities, this heat treatment method includes: subjecting the head part of the rail to accelerated cooling at a cooling rate of 5-30°C/sec from a temperature of 700°C or higher, at which the head surface temperature is in an austenite region, after a finish-rolling step in the hot-rolling process; stopping the accelerated cooling when the surface temperature of the head part of the rail has reached 550-650°C; and subsequently keeping the head part of the rail in a temperature range between 550°C and 650°C for 5-180 sec. COPYRIGHT: (C)2010,JPO&INPIT |
