PURPOSE: To manufacture advantageously a grain-oriented silicon steel sheet with high magnetic flux density and a small iron loss by coating the surface of a silicon steel with different protective coating materials for annealing without overlapping the materials so as to make the secondary recrystallized grains heterogeneous.
CONSTITUTION: A silicon steel slab is hot rolled, cold rolled to the final thickness, and subjected to decarburization and primary recrystallization annealing. The surface of the resulting steel sheet is coated with two or more kinds of protective coating materials for annealing having different compositions without overlapping the materials. The coated surface is alternately coated with MgO- base protective coating materials for annealing at 1W50mm intervals, and secondary recrystallization annealing and purification annealing are carried out.
KOMATSUBARA MICHIROU
ITOU ISAO
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