NON-ORIENTED ELECTROMAGNETIC STEEL SHEET AND METHOD FOR MANUFACTURING SAME, AND MOTOR CORE AND METHOD FOR MANUFACTURING SAME

摘要

A non-oriented electrical steel sheet being excellent in strength and iron loss and having an average magnetostriction λp-p at 400 Hz and 1.0 T of not more than 4.5 × 10-6, and area ratio of recrystallized grains at a section in rolling direction of steel sheet of 40 to 95% and an average grain size of 10 to 40 µm is obtained by subjecting a steel slab containing, in mass%, C: not more than 0.005%, Si: 2.8 to 6.5%, Mn: 0.05 to 2.0%, Al: not more than 3.0%, P: not more than 0.20%, S: not more than 0.005%, N: not more than 0.005%, Ti: not more than 0.003%, V: not more than 0.005% and Nb: not more than 0.005% and satisfying Si - 2A1 - Mn ≥ 0 to hot rolling, hot-band annealing, cold rolling and finish annealing under adequate cold rolling conditions and finish annealing conditions, and a motor core is manufactured by using such a steel sheet.