| 摘要 |
PROBLEM TO BE SOLVED: To provide a continuous hardening heat treatment method for a head of a rail with a special section, which can inhibit the rail with the special section from being deformed in the process of hardening the head of the rail with the special section by the heat treatment. SOLUTION: The hardening heat treatment method for the head of the rail with the special section (specially sectioned rail) is a method of relatively moving the rail with respect to a heat treatment apparatus, and comprises the steps of: heating the head and bottom of the specially sectioned rail; forcibly cooling the bottom of the rail with the air at a slightly low cooling rate of 2 to 0.5°C/second, concurrently with forcibly cooling the head of the rail with the air at a high cooling rate of 5 to 3°C/second down to a surface temperature of 500°C or lower; and forcibly cooling a selected part of the rail with the air after the surface temperature at the head of the rail has reached 500°C or lower. Thereby heat-treated rail almost does not cause the deformation in the longitudinal and transverse direction of the rail. COPYRIGHT: (C)2007,JPO&INPIT
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