METHOD FOR PRODUCING NON-ORIENTED ELECTROMAGNETIC STEEL SHEET, METHOD FOR PRODUCING MOTOR CORE, AND MOTOR CORE.

摘要

In producing a non-oriented electromagnetic steel sheet by hot rolling, cold rolling, finish annealing, and straightening annealing a steel slab comprising, in mass%, at most 0.0050% C, 2-7% Si, 0.05-2.0% Mn, at most 0.2% P, at most 0.005% S, at most 3% Al, at most 0.005% N, at most 0.003% Ti, at most 0.005% Nb and at most 0.005% V, a non-oriented electromagnetic steel sheet that has high strength after the finish annealing and in which reduction in magnetic flux density is suppressed after the straightening annealing is obtained by adjusting the conditions for the finish annealing and the straightening annealing such that the yield stress of the steel sheet after the finish annealing is at least 400 MPa and the ratio (B50S/B50H) of the magnetic flux density B50S after subjecting, to the straightening annealing, the steel sheet after the finish annealing to the magnetic flux density B50H of the steel sheet after the finish annealing is at least 0.99. Also, a motor core is produced by using said steel sheet.