| 摘要 |
PURPOSE:To stably obtain a product having high magnetic flux density and reduced in iron loss by subjecting a slab of silicon steel, where specific amounts of Ni are added, to rolling, to decarburizing annealing, and to nitriding treatment in a traveling state. CONSTITUTION:A slab of a silicon steel having a composition consisting of, by weight ratio, 0.020-0.075% C, 2.5-5.0% Si, 0.05-0.45% Mn, <=0.015% S, 0.010-0.050% acid-soluble Al, 0.0010-0.012% N, 0.05-1.0% Ni, and the balance Fe with inevitable impurities is heated up to <=1200 deg.C and hot-rolled. The resulting steel plate is subjected to hot rolled plate annealing, to cold rolling at >=80% final rolling rate, and to decarburizing annealing. Then nitriding treatment is applied to the strip in a traveling state in a gaseous mixture of hydrogen, nitrogen, and ammonia to regulate N content in the steel. Successively, a separation agent at annealing is applied and finish annealing is done. By this method, the grain-oriented silicon steel sheet improved in hot rolled structure and having low iron loss and high magnetic flux density can be obtained. |
