MANUFACTURING METHOD FOR UNIDIRECTIONAL ELECTROMAGNETIC STEEL SHEET

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.