The chemical affinity between silicon and oxygen is so great that ferrosilicon is used as a deoxidizer (precipitation deoxidization and diffusion deoxidization) in the steelmaking industry. Except for rimmed steel and semi-killed steel, the silicon content in steel should not be less than 0.10%. Silicon does not form carbides in steel, but exists as a solid solution in ferrite and austenite. Silicon plays an important role in improving the strength of solid solution and the rate of cold working deformation and hardening, but it reduces the toughness and plasticity of steel. The influence to steel hardenability is medium, but can improve steel tempering stability and oxidation resistance, so ferrosilicon is used as alloy agent in steelmaking industry. Silicon also has higher resistance, worse thermal conductivity and stronger magnetic conductivity. There is a certain amount of silicon in steel, which can improve the permeability of steel, reduce hysteresis loss and eddy current loss. Electrical steel contains 2% ~ 3% Si, but requires low titanium and boron content. The addition of silicon in cast iron can prevent the formation of carbide and promote the precipitation and spheroidization of graphite. Silicon magnesium iron is a common spheroidizing agent. Ferrosilicon containing barium, zirconium, strontium, bismuth, manganese, rare earth, etc., used as inbreeding agent in cast iron production. High silicon iron is a reducing agent for producing low carbon ferroalloy in ferroalloy industry. Ferrosilicon powder containing about 15% silicon (particle size <0.2mm) is used as a weight enhancing agent in heavy medium mineral processing.
