Silicon steel coils are silicon alloy steels containing 1.0 to 4.5% silicon and less than 0.08% carbon, called silicon steel. It has the characteristics of high magnetic permeability, low coercivity, and large resistivity, so hysteresis loss and eddy current loss are small. It is mainly used as magnetic material in motors, transformers, electrical appliances and electrical instruments. In order to meet the needs of punching and shearing processing in the manufacture of electrical appliances, a certain degree of plasticity is also required. In order to improve the magnetic induction performance and reduce the hysteresis loss, it is required that the content of harmful impurities is as low as possible, and the plate shape is required to be flat and the surface quality is good.