| 摘要 |
PURPOSE:To reduce the dispersion of hardness of a rail head, by specifying the switching temp. between both cooling stages mentioned below at the time of carrying out the continuous cooling transformation heat treatment of a rail head by means of a spray water cooling zone and an air blast cooling zone and forming the surface structure into pearlite structure. CONSTITUTION:A heated rail 1 is allowed to perform reciprocating motion in a water cooling zone (between I and II) and cooled by means of spray water from water-cooling nozzles 3 provided to the upper part and both sides of the head of a rail 1. Subsequently, the rail 1 is allowed to perform reciprocating motion in an air blast cooling zone (between III and IV) and air-cooled by means of air from air-cooling nozzles 3 provided to the upper part and both sides of the head of the rail 1. At this time, the temp. of the rail 1 at the time of switching from spray water cooling to air blast cooling is set up at >=530 deg.C. By this method, the dispersion of hardness of the rail 1 is minimized, air source equipment is miniaturized, and running costs can be reduced.
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