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AssigneeNippon Steel Corporation
InventorsMasato YASUDA, Hideyuki HAMAMURA, Kimihiko SUGIYAMA, Nobusato MORISHIGE
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The present invention has as its object to provide grain-oriented electrical steel sheet further improved in core loss in control of magnetic domains by forming laser grooves in steel sheet after decarburization annealing and before finish annealing. The grain-oriented electrical steel sheet according to the present invention is a grain-oriented electrical steel sheet having a plurality of grooves on the surface of the steel sheet and provided with a glass coating on that surface, which grain-oriented electrical steel sheet characterized in that an absolute value of an angle θ formed by a direction perpendicular to both a rolling direction and sheet thickness direction of the steel sheet and a longitudinal direction of the grooves is 0 to 40°, a width W of the grooves is 20 to 300 μm, a depth D of the grooves is 10 to 40 μm, and a pitch P of the grooves in the rolling direction is 1.0 to 30 mm and in that the relationship of formula (1) is satisfied when a thickness of the glass coating of flat parts of the steel sheet surface (parts other than grooves) is t1 and the thickness of the glass coating at the deepest parts of the grooves is t2: t2/t1<1.00 formula (1)
A grain-oriented electrical steel sheet having a plurality of grooves on a surface of the steel sheet and provided with a glass coating on that surface, which grain-oriented electrical steel sheet characterized in that an absolute value of an angle θ formed by a direction perpendicular to both a rolling direction and sheet thickness direction of the steel sheet and a longitudinal direction of the grooves is 0 to 40°, a width W of the grooves is 20 to 300 μm, a depth D of the grooves is 10 to 40 μm, and a pitch P of the grooves in the rolling direction is 1.0 to 30 mm, and
Dependencies are inferred from the claim text.