| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a heat treatment method, and a device thereof in which the uniform tempering over the thickness direction, softening, etc., of only a surface layer of a steel, and temper-softing in the thickness direction of the steel can be performed while the productivity is not impaired and the surface temperature of the steel plate does not exceed the target value. SOLUTION: In the heat treatment method of the steel which is hardened or accelerated-cooled after the hot rolling is completed, only the surface layer of the steel 2 is heat-treated by a solenoid type induction heater 6. In addition, the power of the solenoid type induction heater 6 can be adjusted according to the size of the steel 2, the steel 2 is subjected to the intermittent heating by passing the steel through at least two solenoid induction heaters 6-1 to 6-6 which are installed with intervals therebetween, the steel 2 is intermittently heated by reciprocatively passing the steel 2 at least three time, and the steel can be heated by a next induction heater after the surface temperature of the steel 2 reaches below the highest possible temperature heated by the previous induction heater.</p> |
