Abstract: In a continuous annealing line for steel sheets comprising a heating zone, a soaking zone and a cooling zone, two or more induction heating devices are arranged in series in a front half part of the heating zone, and a heating stop region of 1˜30 m in length or a slow heating region having a heating rate of more than 0° C./s but not more than 10° C./s is provided in a temperature zone that the temperature of the steel sheet between two or more induction heating devices is 250° C. to 600° C. Even if the steel sheet is rapidly heated at a heating rate of not less than 50° C./s with such a rapid heating apparatus of the heating zone, the temperature distribution in the steel sheet is uniformized to realize the quality improvement of steel sheet shape or magnetic properties and so on.

Abstract: In a continuous annealing line for steel sheets comprising a heating zone, a soaking zone and a cooling zone, two or more induction heating devices are arranged in series in a front half part of the heating zone, and a heating stop region of 1˜30 m in length or a slow heating region having a heating rate of more than 0° C./s but not more than 10° C./s is provided in a temperature zone that the temperature of the steel sheet between two or more induction heating devices is 250° C. to 600° C. Even if the steel sheet is rapidly heated at a heating rate of not less than 50° C./s with such a rapid heating apparatus of the heating zone, the temperature distribution in the steel sheet is uniformized to realize the quality improvement of steel sheet shape or magnetic properties and so on.