Adding a certain amount of silicon to steel can significantly improve the strength, hardness and elasticity of steel. Therefore, when smelting structural steel (containing silicon 0.40-1.75%), tool steel (containing SiO.30-1.8%), spring steel (containing SiO.40-2.8%) and transformer silicon steel (containing silicon 2.81-4.8%), Ferrosilicon is also used as an alloying agent. At the same time, it is an effective new technology to improve the quality of steel, reduce the cost and save iron by improving the shape of inclusions and reducing the content of gas elements in liquid steel. It is especially suitable for deoxidization of molten steel in continuous casting. The practice has proved that ferrosilicon not only meets the deoxidization requirements of steel making, but also has the desulfurization performance and has the advantages of heavy ratio and strong penetration.