Silicon steel is a ferrosilicon alloy. Sheets rolled with silicon steel are the most widely used soft magnetic materials in the electrical field, so silicon steel sheets are also called electrical steel sheets. Silicon steel sheets are widely used in generators, motors, transformers, relays, chokes, electromagnetic mechanisms, and measuring instruments.
The amount of silicon directly affects the properties of the silicon steel sheet. Silicon is a good deoxidizer for steel. The combination of silicon and oxygen converts oxygen into a steady-state SiO2 that is not reduced by carbon, avoiding lattice distortion of iron due to oxygen atom doping. Generally, iron containing impurities can reduce the coercive force and iron loss and increase the magnetic permeability after being added to silicon. But the silicon content is not as high as possible. Excessive increase in silicon content will increase the hardness of the material, increase the brittleness, and reduce the toughness and thermal conductivity, which is unfavorable for heat dissipation and mechanical processing. Therefore, the silicon content of the general silicon steel sheet does not exceed 4.5%.
Carbon, sulfur and oxygen are the three most harmful substances in silicon steel sheets. These elements increase the coercivity of the soft magnetic material and increase the hysteresis loss of the silicon steel sheet. In addition, too much nitrogen also hinders grain growth, resulting in hysteresis loss and coercive force. Silicon steel sheets containing more than 0.5% aluminum are too brittle and difficult to process. Therefore, in the production, these impurity elements which have adverse effects on the silicon steel sheet should be eliminated as much as possible.