Manufacturing method of non-directional electromagnetic steel sheet

Abstract

A method for manufacturing non-directional electromagnetic steel plates with high magnetic flux density is proposed. A method for manufacturing a non-directional electromagnetic steel sheet containing 2.5% by mass or more Si is as follows: after hot rolling of steel raw materials, annealing as needed, and cold rolling once or twice or more with intermediate annealing to produce a cold-rolled steel sheet, during the final annealing of the cold-rolled steel sheet, (1) heating from room temperature to a rapid heating stop temperature in the range of 500°C or higher and below the recrystallization start temperature, at an average heating rate of 150°C / s to 250°C / s, and holding for a specified holding time, and then heating the cold-rolled steel sheet at an average heating rate of 20°C / s or higher until the maximum temperature is reached after the holding time; or (2) heating from room temperature to a rapid heating stop temperature above the recrystallization start temperature, at an average heating rate of 150°C / s to 250°C / s, and holding for a specified holding time, and then heating the cold-rolled steel sheet at an average heating rate of 50°C / s or higher until the maximum temperature is reached after the holding time.

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