Since calcium has a strong affinity with oxygen, sulfur, hydrogen, nitrogen and carbon in molten steel, calcium silicon alloy is mainly used for deoxidation, degassing and fixation of sulfur in molten steel. Calcium silicon produces a strong exothermic effect when added to molten steel.
Calcium turns into calcium vapor in the molten steel, which stirs the molten steel and is beneficial to the floating of non-metallic inclusions. After calcium silicon alloy is deoxidized, non-metallic inclusions with larger particles and easy to float are produced, and the shape and properties of the non-metallic inclusions are also changed. Therefore, calcium silicon alloy is used to produce clean steel, high-quality steel with low oxygen and sulfur content, and special performance steel with extremely low oxygen and sulfur content. Adding calcium silicon alloy can eliminate problems such as nodules at the ladle nozzle of steel using aluminum as the final deoxidizer, and blockage of the tundish nozzle in continuous steel casting | ironmaking.
In the outside-furnace refining technology of steel, calcium silicate powder or core wire is used for deoxidation and desulfurization to reduce the oxygen and sulfur content in the steel to very low levels; it can also control the form of sulfide in the steel and improve the utilization rate of calcium. In the production of cast iron, in addition to deoxidizing and purifying, calcium silicon alloy also plays a nurturing role, helping to form fine-grained or spherical graphite; it can evenly distribute graphite in gray cast iron and reduce the tendency of whitening; it can also increase silicon and desulfurize , improve the quality of cast iron.