| 摘要 |
PURPOSE:To produce a nondirectionally oriented electrical steel plate having excellent magnetic characteristics by applying a specific heat treatment to a hot rolled steel plate contg. B prior to cold rolling thereby annihilating the suppressing effect for growth of crystal grains by AlN. CONSTITUTION:The silicon steel contg. <0.050% C, <4.0% Si, 0.1-0.5% Mn, <0.1% Al, <0.1% P, <0.02% S and <0.005% N, and in the case of 0.01-0.02% S, contg. 0.003-0.03% at least 1 kind selected among Ca and rare earth elements, and contg. B so as to contain B/N at 0.2-0.5 according to the contents of N is melted. The ingot thereof is hot-rolled and is then annealed for 2-10min at 700-1,000 deg.C, or is subjected to heat treatment for cooling the same quickly upon lapse of 4-30sec when the temp. at the end of the hot rolling is >=750 deg.C, whereafter the ingot is cold-rolled. Crystal grains are grown under suppressed deposition of AlN by B and with the decreased effect for suppressing the crystallization by AlN, whereby a silicon steel plate having excellent magnetic characteristics is produced. |
