| 摘要 |
PURPOSE:To reduce the hardening cost of a roll and to prevent reduction in the hardness of the neck parts by heat treating the roll in a single rapid heating- rapid cooling stage. CONSTITUTION:A backup roll 1 is put in a heating furnace 2 provided with internal gas burners 21 and both ends of the roll 1 are supported by a pair of rollers 24, 24 and a pair of rollers 25, 25. The neck parts 14, 15 of the roll 1 are covered with covering bodies 3, 3 fitted to the inlet parts 22, 23 of the furnace 2, the roll 1 is rotated and the body of the roll 1 is rapidly heated with the burners 21. The roll 1 is then taken out of the furnace 1 and put in a thermal refining apparatus 5 provided with water-air jetting nozzles 51 and air jetting nozzles 52, 53. Both ends of the roll 1 are rotatably supported by a pair of rollers 54, 54 and a pair of rollers 55, 55. The roll 1 is rotated again and water-air and air are jetted from the nozzles 51, 52, 53 to rapidly cool the roll 1.
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