Method for producing grain-oriented electrical steel sheet, and induction heating device

Abstract

A method for a grain-oriented electrical steel sheet including subjecting a steel material with a predetermined component composition to hot rolling and then to cold rolling to obtain a cold-rolled sheet with a final thickness and subjecting the cold-rolled sheet to decarburization annealing serving as primary recrystallization annealing and then to finishing annealing, in which a final cold-rolling step of the cold rolling includes at least one rolling pass or more performed with the temperature of the steel sheet set in the range of 150° C. to 350° C. inclusive, and the decarburization annealing includes a heating step in which the steel sheet is heated at an average heating rate of 250° C./s or more from 400° C. to a temperature T(° C.) of 700 to 900° C. and then held at a heating rate of 2/3 of the average heating rate or less in any of temperature ranges between 500° C. and 700° C. for a time of 0.10 seconds or more but less than 1.00 seconds. Thus, a grain-oriented electrical steel sheet with excellent magnetic properties is obtained. A transverse induction heating device is used for the rapid heating.

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