In the process of making non grain oriented electrical steel, its silicon steel is mainly smelted by oxygen converter (also can be smelted by electric arc furnace), combined with molten steel vacuum treatment and AOD technology (see furnace refining, using die casting or continuous casting method. The use of silicon (0.5 ~ 4.5%) and aluminum (0.2 ~ 0.5%) content during smelting to meet different magnetic requirements. The high silicon silicon steel sheet and aluminum amount increased accordingly. Carbon, sulfur and inclusions are minimized.
Non grain oriented electrical steel has better magnetic properties, surface quality, filling factor and punching properties than hot-rolled silicon steel sheets, and can be produced in rolls. Therefore, some countries have stopped producing hot-rolled silicon steel sheets since the 1960s. In China, hot-rolled silicon steel sheets are produced by a rapid hot rolling at a low temperature of about 900 ° C and a helium annealing method under hydrogen protection. The finished product ratio is high, and the surface quality and magnetic properties of the finished products are good.
The rolling of silicon steel is divided into two processes: hot rolling and cold rolling. The traditional process of directly producing silicon steel finished products by hot rolling has been rarely used, mainly in the two processes of hot rolling and cold rolling, called cold rolled silicon steel. product. According to different products, the cold rolling process is divided into multi-stand rolling mill and single-stand rolling, in which single-stand rolling mainly produces oriented silicon steel products.