Method for producing single-oriented electrical steel sheets having a high magnetic induction

Claim 1

In a method for producing single-oriented electrical steel sheets having a magnetic induction of more than 1.85 wb/m 2 including the steps of preparing raw material for the sheets, hot rolling the raw material to a hot strip having an intermediate gauge of 2-/4mm, subjecting said hot strip to repeated annealing and cold rolling steps including a final cold rolled steel sheet having its final gauge and subjecting the resulting sheets to a decarburization annealing and a final annealing to develop secondary recrystallized grains of (110) [001] orientation; the improvement comprising utilizing a raw material formulation consisting essentially of less than 4% of Si less than 0.06% of C, 0.02-0.2% of Mn, 0.005-0.1% in total of at least one of S and Se, at least one member selected from the group consisting of 0.015-0.4% of elements (Xi) and 0.2-1.0% of elements (Xj), said element (Xi) being at least one of As, Bi, Pb, P, Sn,; and said element (Xj) being at least one of Ni and Cu, with the remainder of the materials being iron; said improvement further comprising a two-step final annealing including a secondary recrystallization annealing at a temperature of 800°-920°C. to fully develop the secondary recrystallized grains and a purification annealing at a temperature of 1,100°-1,200°C.