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The role of silicon calcium alloy in steelmaking

Release Time: 2024-01-26
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Calcium-silicon alloy is a composite alloy obtained in a 1500-1800 degree strong reduction atmosphere by silica, lime and coke as raw materials, which belongs to the category of ferro alloy. The main components of silicon calcium alloy are silicon and calcium, but also contain different components of iron, aluminum, carbon, sulfur and phosphorus and other impurities. Iron and steel industry used as calcium additives, deoxidizer, desulfurizer and nonmetallic inclusions denaturant. Cast iron industry used as inoculant and denaturant.


Silicon calcium alloy is widely used in the production of high quality steel, low carbon steel, stainless steel and special alloys such as nickel base alloy and titanium base alloy. It is suitable to be used as a warming agent for converter steelmaking workshop. It can also be used as inoculant of cast iron and additive in ductile iron production.

The role of silicon calcium alloy

Because calcium has a strong affinity with oxygen, sulfur, hydrogen, nitrogen and carbon in liquid steel, calcium silicon alloy is mainly used for deoxidation, degassing and fixing sulfur in liquid steel. The addition of silicon calcium to molten steel produces a strong exothermic effect. Calcium becomes calcium vapor in the molten steel, which has stirring effect on the molten steel and is beneficial to the floating of non-metallic inclusions. After the deoxidation of Si-Ca alloy, the non-metallic inclusions with large particles and easy to float are produced, and the shape and properties of the non-metallic inclusions are also changed.

Therefore, silicon calcium alloy is used to produce clean steel, excellent L-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 in the ladle water mouth, and the blockage of the water mouth of the intermediate tank of continuous cast steel |. In the process of steel refining, calcium silicon powder or core wire is used to deoxidize and desulphurize, so that the content of oxygen and sulfur in steel is very low. 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 a role in inoculation, which helps to form fine or spherical graphite; Make the graphite distribution in gray cast iron uniform, reduce the white tendency; And can increase silicon, desulfurization, improve the quality of cast iron.


According to the content of silicon and calcium, silicon calcium alloy is divided into: Ca31Si60, Ca28Si60, Ca24Si60, Ca20Si55, Ca16Si55.

In addition, on the basis of silicon calcium alloy, other elements are added to form a ternary or multivariate composite alloy. Such as Si-Ca-Al; Si-Ca-Mn; Si-Ca-Ba, etc., used as a deoxidizer, desulfurizer, denitrification agent and alloying agent in iron and steel metallurgy.

Mark Chemical Component%
Ca Si C AI P S
Ca31Si60 31 50-60 1.2 2.4 0.04 0.06
Ca28Si60 28 50-60 1.2 2.4 0.04 0.06
Ca24Si60 24 50-60 1.2 2.5 0.04 0.06
Ca20Si55 20 45-55 1.2 2.5 0.04 0.06
Ca16Si55 16 45-55 1.2 2.5 0.04 0.06


Production technology of silicon calcium alloy

In fact, the method of industrial production of silicon-calcium alloy is realized by using CaC2 as the transition product. The density of silicon calcium alloy is slightly smaller than the slag, and the smelting process of silicon calcium alloy is basically concentrated in the upper part of the melting pool, which is the characteristic of smelting silicon calcium alloy. Special measures should be taken to separate it from the slag. According to the above analysis, there are three kinds of processes for smelting silicon calcium alloy by electrocarbonothermal (reduction) method, that is, mixed feeding method, layered feeding method and calcium carbide method. Electrosilicothermic (reduction) method is also one of the methods for producing silica-calcium alloys.

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