In the production of low alloy structural steel, ferrosilicon (FeSi) plays a key role as an important alloying additive. Low alloy structural steel generally uses Low Carbon Ferro Silicon and Medium Carbon Ferro Silicon as alloying agents and deoxidizers.

Low Carbon Ferro Silicon: It is the most commonly used ferrosilicon specification in low alloy structural steel. Usually its silicon content is 60% - 75%, and its carbon content is below 0.5%. This specification of ferrosilicon is suitable for deoxidation and alloying in the production of low alloy structural steel, especially in the production of low carbon steel and high quality steel.

Medium Carbon Ferro Silicon: Some low alloy structural steels may use medium carbon ferrosilicon when a higher silicon content is required. Its silicon content is also between 60% - 75%, but the carbon content is slightly higher, generally 1% - 3%. It is suitable for alloying processes where a certain amount of carbon and silicon is required for steel grades.

Ferrosilicon for low alloy structural steel

chemical composition

Grade	Chemical Composition(mass fraction)%
	Si	Al	Ca	Mn	Cr	P	S	C
		≤
FeSi90Al1.5	87.0~95.0	1.5	1.5	0.4	0.2	0.04	0.02	0.2
FeSi9oAl3.0	87.0~95.0	3	1.5	0.4	0.2	0.04	0.02	0.2
FeSi75Al0.5-A	74.0~80.0	0.5	1	0.4	I0.3	0.035	0.02	0.1
FeSi75Al0.5-B	72.0~80.0	0.5	1	0.5	0.5	0.04	0.02	0.2
FeSi75Al1.0-A	74.0~80.0	1	1	0.4	0.3	0.035	0.02	0.1
FeSi75Al1.0-B	72.0~80.0	1	1	0.5	0.5	0.04	0.02	0.2
FeSi75Al1.5-A	74.0-80.0	1.5	1	0.4	0.3	0.035	0.02	0.1
FeSi75Al1.5-B	72.0~80.0	1.5	1	0.5	0.5	0.04	0.02	0.2
FeSi75Al2.0-A	74.0~80.0	2	1	0.4	0.3	0.035	0.02	0.1
FeSi75Al2.0-B	72.0~80.0	2		0.5	0.5	0.04	0.02	0.2
FeSi75-A	74.0~80.0			0.4	0.3	0.035	0.02	0.1
FeSi75-B	72.0~80.0			0.5	0.5	0.04	0.02	0.2
FeSi65	65.0~72.0			0.6	0.5	0.04	0.02

The role of ferrosilicon in the production of low-alloy structural steel

Deoxidation

Deoxidation is the process of removing oxygen impurities from molten steel in steel production. Ferrosilicon, as a deoxidizer, reacts with oxygen in molten steel to generate silicon oxide (SiO₂) and remove oxygen from the steel. For low-alloy structural steel, removing oxygen impurities is a key step to improve the purity of steel, improve the quality of steel, avoid pores and inclusions in steel, and enhance the mechanical properties of steel.

Alloying

Silicon is one of the commonly used alloying elements in low-alloy steel. Adding ferrosilicon can increase the silicon content in molten steel, thereby improving the oxidation resistance, corrosion resistance and high-temperature strength of steel. The addition of silicon also helps to improve the machinability of steel and increase the hardness of steel.

Control the content of other elements in steel

In steel smelting, ferrosilicon not only provides silicon, but also can adjust the proportion of other elements in molten steel, especially in the alloying process to control the relative content of other elements (such as manganese, chromium, molybdenum, etc.), so that low-alloy structural steel has specific mechanical and chemical properties.

Promote the fluidity of molten steel

The addition of ferrosilicon can improve the fluidity of molten steel, help the uniform casting of molten steel during the casting process, and reduce casting defects such as pores and inclusions.

Improve the cold working performance of steel

Silicon alloy steel has good plasticity and toughness during cold working. The addition of silicon improves the cold working performance of low-alloy structural steel to a certain extent, and is suitable for steel that requires cold rolling, cold drawing and other processing processes.

Ferrosilicon for low alloy structural steel