Let's learn about silicon-calcium alloy

A binary alloy composed of silicon and calcium belongs to the category of ferroalloys. Its main components are silicon and calcium, and it also contains impurities such as iron, aluminum, carbon, sulfur and phosphorus in varying amounts. In the iron and steel industry, it is used as a calcium additive, deoxidizer, desulfurizer and denaturant for non-metallic inclusions. It is used as an inoculant and denaturant in the cast iron industry. Calcium-silicon alloys are classified according to the content of calcium and silicon, and other impurities are regulated according to different uses. In addition, on the basis of silicon-calcium alloys, other elements are added to form ternary or multi-element composite alloys. Such as Si-Ca-Al; Si-Ca-Mn; Si-Ca-Ba, etc., used as deoxidizer, desulfurizer, denitrification agent and alloying agent in iron and steel metallurgy.

Since calcium has a strong affinity with oxygen, sulfur, hydrogen, nitrogen and carbon in molten steel, silicon-calcium alloys are 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 molten steel, which has a stirring effect on molten steel and is beneficial to the floating of non-metallic inclusions. After the silicon-calcium alloy is deoxidized, non-metallic inclusions with larger particles and easy to float are produced, and the shape and properties of non-metallic inclusions are also changed. Therefore, silicon-calcium 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. The addition of silicon-calcium alloy can eliminate the nodulation of the steel with aluminum as the final deoxidizer at the ladle nozzle, and the clogging of the nozzle of the tundish of continuous casting | ironmaking. In the external refining technology of steel, silicon-calcium powder or core wire is used for deoxidation and desulfurization to reduce the content of oxygen and sulfur in steel to a very low level; it can also control the form of sulfide in steel and improve the utilization rate of calcium. In the production of cast iron, in addition to deoxidation and purification, silicon-calcium alloy also plays an inoculating role, which helps to form fine-grained or spherical graphite; makes the graphite in gray cast iron evenly distributed, reduces the tendency of whitening; and can increase silicon and desulfurize , Improve cast iron quality.