Method for producing grain-oriented electrical steel sheet

A method for producing a grain-oriented electrical steel sheet, the method comprising subjecting a slab having a chemical composition comprising, by mass %:

• C:
• 0.002% to 0.10%;
• Si:
• 2.5% to 6.0%;
• Mn:
• 0.010% to 0.8%;
• Al:
• less than 0.010%;
• N:
• less than 0.0050%;
• Se:
• 0.0030% or less;
• S:
• less than 0.0050%;
• and
• the remainder being Fe and inevitable impurities,
• where a mass ratio Al/N of Al and N is not less than 1.4, to hot rolling, hot band annealing, one or two or more cold rollings sandwiching an intermediate annealing therebetween to form a steel sheet, formation of subscale on a surface of the steel sheet through decarburization annealing, application of an annealing separator composed mainly of MgO onto the steel sheet surface and finish annealing,
• wherein when a certain temperature within a range of 700 to 800° C. in a heating process of the decarburization annealing is T1 and a certain temperature as a soaking temperature within a range of 820 to 900° C. is T2, a heating rate R1 between 500° C. and T1 is set to not less than 100° C./s and a heating rate R2 between T1 and T2 is set to not more than 15° C./s.