Kawasaki Steel Corporation

Koh Nakano

Keiji Sato

Atsuhito Honda

Bunjiro Fukuda

A method and a low iron loss grain-oriented electromagnetic steel sheet are disclosed. The method comprises the steps of: hot-rolling a grain-oriented electromagnetic steel sheet; cold-rolling the hot-rolled steel sheet once or twice intervened by intermediate annealing, so as to achieve the sheet thickness of a final product; annealing the cold-rolled steel sheet for decarburization; finish-annealing the decarburized steel sheet; forming linear grooves on the steel sheet substantially perpendicularly to the rolling direction, after the final cold-rolling step and before the finish-annealing step, by, for example, electrolytic etching or acid dipping; and filling the linear grooves with an element selected from the group consisting of Sn, B and Sb, or an oxide or a sulfate of an element selected therefrom. Preferably, each of the linear grooves has a width of 30-300 &mgr;m and a depth of 5-100 &mgr;m, and extends at 60-90&deg; to the rolling direction, and is apart from the adjacent groove by 1 mm measured parallel to the rolling direction.

Method and low iron loss grain-oriented electromagnetic steel sheet

A low-iron loss grain oriented electromagnetic steel sheet subjected to final finishing annealing has a plurality of linear grooves formed on surface of the steel sheet in a direction across the rolling direction, so as to improve the magnetic characteristics of the steel sheet. The linear grooves have a substantially rectangular cross-sectional shape in which the angle of a groove side wall to the direction of the thickness of the sheet is about 60.degree. or less. Projections are present at a bottom portion of the groove, and the depth at the top of the projection at the groove bottom is at least about 1/2 of the maximum groove depth. The steel sheet maintains a low iron loss even after stress relief annealing. The present invention provides a method of stably producing the steel sheet.

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Okayama, Japan

Koh Nakano