Nippon Steel Corporation

Nobuo Tachibana

Eiichi Nanba

Yousuke Kurosaki

Satoshi Arai

Kazutoshi Takeda

Shuichi Yamazaki

Kenji Kosuge

Kishio Mochinaga

Naoki Yagi

Shinya Ishii

Fumikazu Ando

Katsuyuki Yanagihara

Norito Abe

Kentaro Chikuma

Kiyokazu Ichimura

Sadanobu Hirokami

Masayuki Yamashita

The present invention is a grain-oriented electrical steel sheet characterized in that Bi is present at 0.01 to less than 1,000 ppm in terms of mass at the interface of the substrate steel and the primary film of the grain-oriented electrical steel sheet. The grain-oriented electrical steel sheet is produced by any of the processes of: before decarburization annealing, applying preliminary annealing for 1 to 20 sec. at 700&#xb0; C. or higher and controlling an atmosphere in the temperature range; controlling the maximum attaining temperature B (&#xb0; C.) before final cold rolling so that the maximum attaining temperature B may satisfy the expression, &#x2212;10&#xd7;ln(A)+1,100&#x2266;B&#x2266;10&#xd7;ln(A)+1,220, in accordance with a Bi content A (ppm) and at the same time heating the steel sheet cold rolled to the final thickness to 700&#xb0; C. or higher within 10 sec. or at a heating rate of 100&#xb0; C./sec. or more before decarburization annealing, or immediately thereafter applying preliminary annealing for 1 to 20 sec. at 700&#xb0; C. or higher; or controlling a TiOamount B added in relation to MgO of 100 as parts by weight and an MgO coating amount C (g/m) so that the expression, A&#x2266;B&#xd7;C&#x2266;400, may be satisfied in accordance with the Bi content A (ppm).

Ultra-high magnetic flux density grain-oriented electrical steel sheet excellent in iron loss at a high magnetic flux density and film properties and method for producing the same

Grain-oriented electrical steel sheet excellent in film characteristics and magnetic characteristics, process for producing same, and decarburization annealing facility used in same process

A process for producing a grain-oriented electrical steel sheet wherein during the decarburization annealing step, the steel sheet is first rapidly heated in a rapid heating chamber and the PH O/PH ratio in the rapid heating chamber is more than the PH O/PH ratio in the decarburization annealing furnace so as to provide improved oxide film adhesion.

Method of producing unidirectional electromagnetic steel sheet having excellent film characteristics and magnetic characteristics

Grain-oriented electrical steel sheet and method for producing same

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Himeji, Japan

Nobuo Tachibana