Nippon Steel Corporation

Naoto Masumitsu

Nobusato Morishige

Masaru Takahashi

Hideyuki Hamamura

Takashi Kataoka

Yasuhiro Mayumi

Hirotoshi Tada

Kazuhiko Fukutani

Toshiya Takechi

Tomoya Suenaga

Haruhiko Atsumi

Masamitsu Kubota

Shin Furutaku

Junichi Takaobushi

A method for manufacturing a grain-oriented electrical steel sheet according to an aspect of the present invention includes a step of obtaining a hot-rolled steel sheet by carrying out hot rolling on a slab containing a predetermined component composition with a remainder including Fe and impurities, a step of obtaining a hot-rolled annealed sheet by carrying out hot-rolled sheet annealing as necessary, a step of carrying out pickling to obtain a pickled sheet, a step of carrying out cold rolling to obtain a cold-rolled steel sheet, a step of carrying out primary recrystallization annealing, a step of applying an annealing separating agent including MgO to a surface and then carrying out final annealing to obtain a final-annealed sheet, and a step of applying an insulating coating and then carrying out flattening annealing.

Method for manufacturing grain-oriented electrical steel sheet and grain-oriented electrical 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&#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.

Method of manufacturing grain-oriented electrical steel sheet

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Narashino, Japan

Naoto Masumitsu