| 摘要 |
PURPOSE:To provide a nonoriented silicon steel sheet having high magnetic flux density and low iron loss by constituting a silicon steel sheet of a ferritic structure constituted of specified wt.% of C, N, Si, P, S, Al, Ti and Mn and the balance Fe and having specified grain size. CONSTITUTION:Steel is constituted of a compsn. contg., by weight, <=0.004% C, <=0.004% N, <=1% Si, <=0.15% P, <=0.005% Si, <=1% Al, <=0.05% Ti as well as the value more than that in the formula I and <=0.5% Mn and the balance Fe with inevitable impurities. Then, the objective nonoriented silicon steel having a ferritic structure with 100 to 300mum grain size is constituted. As for this steel, in its recrystallization annealing after cold rolling, the maximum temp. of the annealing is regulated to >=T deg.C at which the Si content and Al content lie in the relationship in the formula II, and in the cooling stage, the average cooling rate from T deg.C to T deg.C-30 deg.C is regulated to <=80 deg.C/S. In this way, energy loss in a motor or the like can be reduced. |
