Method for manufacturing a grain-oriented electrical steel sheet

A method for manufacturing a grain-oriented electrical steel sheet having a forsterite film and a tension-applying insulating coating at both of one surface and an opposite surface thereof, the method comprising:

• hot rolling a slab to obtain a hot rolled sheet;
• optionally subjecting the hot rolled sheet to hot band annealing;
• subsequently subjecting the hot rolled sheet to cold rolling once, or twice or more with intermediate annealing in-between, to obtain a cold rolled sheet of final sheet thickness;
• subsequently subjecting the cold rolled sheet to decarburization annealing to obtain a decarburization annealed sheet;
• subsequently applying an annealing separator having MgO as a main component onto both of one surface and an opposite surface of the decarburization annealed sheet and then subjecting the decarburization annealed sheet to final annealing to form the forsterite film and obtain a final annealed sheet;
• and
• subsequently applying an insulating coating treatment liquid onto both of one surface and an opposite surface of the final annealed sheet and then subjecting the final annealed sheet to flattening annealing that also serves as baking to form a tension-applying insulating coating on both of the one surface and the opposite surface of the final annealed sheet to obtain the grain-oriented electrical steel sheet, wherein
• in formation of the forsterite film and the tension-applying insulating coating in both of the one surface and the opposite surface of the sheet,
• an absolute value of a difference between total tension of the forsterite film and the tension-applying insulating coating in the one surface of the sheet and total tension of the forsterite film and the tension-applying insulating coating in the opposite surface of the sheet is adjusted to less than 0.5 MPa,
• an absolute value of a difference between tension of the forsterite film in the one surface of the sheet and tension of the forsterite film in the opposite surface of the sheet is adjusted to 0.5 MPa or more, and
• an absolute value of a difference between tension of the tension-applying insulating coating in the one surface of the sheet and tension of the tension-applying insulating coating in the opposite surface of the sheet is more than 0 MPa.