Nkk Corporation

Tsunehiro Yamaji

Tatsuhiko Hiratani

Shoji Kasai

Yoshikazu Takada

Misao Namikawa

Hironori Ninomiya

A silicon steel sheet having low iron loss of high frequency has a surface layer of the steel sheet which has Si concentration higher than Si concentration of a center portion of the steel sheet. Si concentration of sheet thickness center is 3.4 wt. % or more and Si concentration of the surface layer of the steel sheet is 5 wt. % or more. Si concentration in a surface layer portion is 5 to 8 wt. %. The production method comprises siliconizing treatment and diffusing treatment. Velocity of siliconizing and diffusing are controlled, and Si concentration distribution in the sheet thickness direction of the steel sheet is controlled.

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Kawasaki, Japan

Tsunehiro Yamaji