Silicon alloy steel with silicon content of 1.0~4.5% and carbon content less than 0.08% is called silicon steel. It has the characteristics of high magnetic permeability, low coercivity and large resistivity, so the hysteresis loss and eddy current loss are small. Mainly used as magnetic materials 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 plasticity is also required. In order to improve the magnetic inductance performance and reduce hysteresis loss, the lower the content of harmful impurities, the better, and the plate shape is required to be flat and the surface quality is good.