Nippon Steel Corporation

Junichi Takaobushi

Masaru Takahashi

Nobusato Morishige

Hirotoshi Tada

Naoto Masumitsu

Shin Furutaku

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&#xb0; C. of 1150&#xb0; C. to 1300&#xb0; C., retaining the slab for 5 minutes to 30 hours, lowering the temperature of the slab to T2&#xb0; C. of T1&#x2212;50&#xb0; C. or lower, heating the slab at T3&#xb0; C. of 1280&#xb0; C. to 1450&#xb0; 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&#xb0; C. satisfying 170+[Bi]&#xd7;5000&#x2264;T&#x2264;300 is performed one time to four times. A heating rate in the decarburization annealing process is 50&#xb0; C./second or faster.

Growing community of inventors

Himeji, Japan

Junichi Takaobushi