Method of manufacturing grain-oriented electrical steel sheet

Abstract

Provided is a method of manufacturing a grain-oriented electrical steel sheet including: a heating process of heating a slab having a predetermined chemical composition at T1° C. of 1150° C. to 1300° C., retaining the slab for 5 minutes to 30 hours, lowering the temperature of the slab to T2° C. of T1−50° C. or lower, heating the slab at T3° C. of 1280° C. to 1450° C., and retaining the slab for 5 minutes to 60 minutes; a hot-rolling process of hot-rolling the slab that is heated to obtain a hot-rolled steel sheet; a cold-rolling process; an intermediate annealing process of performing intermediate annealing with respect to the hot-rolled steel sheet at least one time before the cold-rolling process or before a final pass of the cold-rolling process after interrupting the cold-rolling; an annealing separating agent applying process; and a secondary film applying process. In the cold-rolling process, a retention treatment is performed during a plurality of passes. In the retention treatment, retention at a temperature T° C. satisfying 170+[Bi]×5000≤T≤300 is performed one time to four times. A heating rate in the decarburization annealing process is 50° C./second or faster.