| 摘要 |
PURPOSE:To produce a grain oriented silicon steel sheet having high magnetic flux density by incorporating specific percentage of Pb into a slab material of specific composition, specifying cooling velocity from a specific hot rolled plate soaking temp., and also specifying average crystalline grain size after decarburizing annealing. CONSTITUTION:The slab material has a composition consisting of, by weight, 0.025-0.10% C, 2.5-4.5% Si, 0.05-0.45% Mn, <=0.014% (S+ 0.405Se), 0.01-0.06% acid soluble Al, 0.0005-0.013% N, and the balance Fe with inevitable impurities. This slab is heated to <=1280 deg.C, hot-rolled, and cold-rolled at >=50% final cold rolling draft. Further, decarburizing annealing and finish annealing are executed, and nitriding treatment is applied in the interine. At this time, Pb is incorporated into the slab material by 0.005-0.50%, and further, cooling velocity through the region between hot rolled plate annealing soaking temp., 900-1200 deg.C, and 750-900 deg.C is regulated to (0.3 to 50) deg.C/sec and also average crystalline grain size after decarburizing annealing is regulated to 13-28mum. By this method, secondary recrystallization can be stabilized. |
