Patent ID: 6891139
Filing Date: 2005-05-10
Classification: B23K,C21D,Y02P

Abstract:
1. A heat treatment apparatus comprising: a plurality of induction heating devices which heat a steel product; a correctional device for correcting the steel product; a computing device which computes supply predetermined electric power which is supplied to the induction heating devices, on the basis of a size of the steel product, a conveying speed of the steel product, heating target temperatures of the steel product, and a predetermined temperature of the steel product at the previous stage of the induction heating devices; and a power supply unit which supplies the supply predetermined electric power computed by the computing device to the induction heating devices, wherein the computing device computes supply predetermined electric power to be supplied to the induction heating devices in order to heat the steel product so that the steel product has a surface temperature equal to or lower than a first target temperature while being heated, and a difference between a second target temperature and a temperature which the steel product has at a predetermined position in the thickness direction of the steel product when the heating is completed falls within a predetermined range, or so that the steel product has a surface equal to or higher than a third target temperature while being heated and has a temperature equal to or lower than a fourth target temperature at the predetermined position in the thickness direction of the steel product when the heating is completed.