| 摘要 |
PROBLEM TO BE SOLVED: To obtain a nonoriented silicon steel sheet reduced in iron loss after magnetic annealing by preparing a nonoriented silicon steel sheet having a specific composition in which respective contents of B and Al are specified. SOLUTION: A nonoriented magnetic steel sheet, having a composition consisting of, by weight, <=0.005% C, <=0.2% P, <=0.005% N, <=1.0% Si, 0.1-1.0% Mn, <=0.004% Al, <=0.01% S, 0.001-0.02% V, further B in an amount satisfying B/N=0.2 to 3.0, and the balance essentially Fe with inevitable impurities, is prepared. By the addition of B as mentioned above, N is fixed as BN and the precipitation of VN is prevented and the coarsening of crystalline grains can be performed, by which the nonoriented magnetic steel sheet reduced in iron loss after magnetic annealing can be obtained. Further, iron loss can be reduced to a greater extent by limiting the content of Al to <0.001%. |
