What is calcium silicon alloy, calcium silicon be know as CaSi ,and Silicon calcium alloy is a metal alloy mainly composed of silicon (S: 55-65%) and calcium (Ca:20-30%), usually containing a small amount of impurities such as iron and aluminum. Silicon calcium alloy is generally used as a deoxidizer and desulfurizer for steelmaking and casting. Common forms include calcium silicon blocks, calcium silicon powder, calcium silicon particles and calcium silicon cored wire.
Applications of calcium silicon
Silicon calcium alloy is a kind of inoculant. Other common inoculants include ferrosilicon, silicon barium, etc. Common grades of calcium silicon include Ca30Si60, Ca28Si60, Silicon calcium alloys with different contents are used in different industries and have different functions.
The most common application of calcium silicon is as a deoxidation and desulfurization agent in the metallurgical and foundry industries, and as a promoter of graphite spheroidization in the foundry industry.
- Silicon calcium alloy is used for deoxidation and desulfurization in the metallurgical industry. In the steelmaking process, silicon-calcium alloy is used as a highly efficient composite deoxidizer. The strong deoxidation ability of calcium and the synergistic effect of silicon can deeply remove oxygen and sulfur from molten steel, forming low-melting-point inclusions (such as CaO·SiO₂), which are easy to float up and remove, significantly improving the purity of the steel.
- Silicon calcium can also be used as alloying additives. Improve steel properties by adjusting the calcium and silicon content in steel. For example, adding silicon-calcium alloy to heat-resistant steel can enhance oxidation resistance; optimizing silicon content in electrical steel can improve magnetic permeability.
- Silicon calcium alloy can change the morphology of inclusions. Calcium can modify hard inclusions such as Al₂O₃ into spherical calcium aluminates, reduce stress concentration, and improve the toughness and fatigue life of steel.
- Silicon calcium alloy is used in the production of ductile iron in the foundry industry . As an inoculant or spheroidizer, silicon calcium alloy promotes graphite spheroidization and improves the strength (tensile strength can reach 500-900 MPa) and ductility (elongation 5-15%) of cast iron. Compared with traditional magnesium treatment processes, the addition of calcium can reduce shrinkage defects.
- Silicon calcium alloy can improve the performance of magnesium alloy . Adding silicon calcium alloy refines the grains, improves the corrosion resistance of magnesium alloy (salt spray test life is extended by more than 30%) and high temperature strength.
- Silicon calcium alloy can also be used as welding rod/flux component in welding material industry. Silicon calcium alloy is used as deoxidizer in welding material to reduce the oxygen content of weld (can be controlled below 50 ppm), reduce pores, and improve the toughness of weld metal (impact energy is increased by 20-30%).
- Silicon calcium alloy can also be widely used in coating material industry. As a component of high temperature anti-oxidation coating, it is used in aircraft engine blades to improve heat resistance (working temperature is increased by 100-200℃).
Market Trend of Calcium Silicon Alloy
Demand growth: With the demand for high-performance materials in new energy vehicles and high-end equipment manufacturing, the application of silicon-calcium alloys in ultra-high strength steel and lightweight alloys continues to expand. The global annual demand growth rate is about 3-5%.
Production concentration: China is the main producer (accounting for more than 70% of global production), and major companies include Ordos Metallurgical Group, Ningxia Yinglite, etc.
Market Trend and Price of Silicon Calcium Alloy in 2025
From December 2024 to April 2025, the average export price of calcium silicon alloy block Ca30Si60 FOB in the Chinese market is US$1,547.02/ton.The average domestic market price of calcium silicon cored wire in China is 10520.13 yuan/ton 。
From the chart, the price of silicon calcium alloy has been falling continuously since the end of December 2024. However, due to the rapid development of the new energy vehicle industry, the demand for steel is increasing. It is expected that the price of silicon calcium alloy will rise in the future.
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