| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacture of a nonoriented silicon steel sheet free from embrittlement problem and excellent in magnetic properties. SOLUTION: Hot rolled plate continuous annealing is applied to a hot rolled steel plate having a composition consisting of, by weight, <=0.003% C, 2.5-4.5% Si, 0.1-2% Al, 0.07-3% Mn, <=0.05% P, <=0.002% S, <=0.003% N, <=0.004% O, and the balance inevitable components to regulate crystalline grain size to >=100μm. Subsequently, cold rolling is applied to the plate and also recrystallization annealing is performed to regulate crystalline grain size to 100-300μm, by which the nonoriented silicon steel sheet can be manufactured. At this time, the thickness of the hot rolled plate and the cooling rate at hot rolled plate annealing is are regulated to 0.8-2.0mm and (1 to 40) deg.C/sec, respectively. |
