Method For Producing Grain Oriented Electrical Steel Sheet

Abstract: This method for producing a grain-oriented electrical steel sheet comprises a hot rolling step, a hot rolled sheet annealing step, a cold rolling step, a decarburization annealing step, a separation agent coating step, a finish annealing step, a surface treatment step, a thermal oxidation-reduction annealing step and a tension-imparting insulating film forming step. The thermal oxidation-reduction annealing step comprises: a primary heating process in which the temperature of a surface-treated steel sheet is raised by heating; a primary annealing process in which the temperature of the steel sheet is maintained at a certain temperature within the range of 800°C to 900°C for a certain retention time within the range of 10 to 200 seconds in an atmosphere in which the oxygen potential PH2O/PH2 is at a certain value within the range of 0.10 to 10.00; and a secondary annealing process in which the temperature of the steel sheet is maintained at a certain temperature within the range of 900°C to 1100°C for a certain retention time within the range of 3 to 100 seconds in an atmosphere in which the oxygen potential PH2O/PH2 is less than 0.1000 and the dew point is at a certain value less than -20°C.

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