Ferro Silicon 75 (FeSi75) and Ferro Silicon 72 (FeSi72) are the workhorse grades of the ferroalloy industry, prized for their high silicon content and cost-effectiveness. While chemically similar, their specific characteristics make them suitable for different primary applications.

FerroSilicon75 (Si: 74-80%): As the industry standard for steelmaking, FeSi75% acts as a powerful and efficient deoxidizer, removing oxygen from molten steel to prevent blowholes and improve ingot quality. It is also the preferred choice for producing high-grade electrical steels (silicon steel) due to its higher silicon concentration.

FerroSilicon72 (Si: 72-80%): Offering an excellent balance of performance and economy, FeSi72% is widely adopted in foundries as an inoculant for gray and ductile iron, promoting graphite formation and improving casting strength. It is also a key raw material in the Pidgeon process for magnesium refining and serves as an effective deoxidizer for many carbon steel grades.

Ferro Silicon

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

75 FeSi Features

High silicon content

It plays an important role in steel smelting and alloy manufacturing.

Good stability

It can maintain the stability of the alloy at high temperatures.

Wide range of applications

It is widely used in the manufacture of ferrosilicon alloys and cast iron in steel alloys

The main use of 75 ferrosilicon is as a deoxidizer and alloying agent in the steelmaking industry, and as an inoculant and spheroidizer in the cast iron industry.

Specifically, 75 ferrosilicon can effectively remove oxygen from molten steel and improve the purity and quality of steel. At the same time, it can also be used as an alloying element additive to improve the performance of steel.

In addition, 75 ferrosilicon is also used as a reducing agent in ferroalloy production and has other applications.

Ferro Silicon 75

72 FeSi Features

Medium to high silicon content

suitable for different types of steel smelting and casting processes.

Good economic efficiency

compared with high silicon content ferrosilicon 75, it has found a balance between cost and performance, making it more competitive in some specific applications

72 Ferrosilicon is mainly used as an alloying element additive, widely used in low alloy structural steel, spring steel, bearing steel, heat-resistant steel and electrical silicon steel, and can also be used as an inoculant for the manufacture of ductile iron and malleable cast iron.

In addition, it can also be used as a reducing agent in ferroalloy production and chemical industry.

Ferro Silicon 72

In-Depth Application Guide for FeSi75/72

For Steelmaking (Deoxidation & Alloying):

The high silicon content in both FeSi 75 and FeSi 72 has a strong affinity with oxygen. When added to molten steel, it rapidly combines with dissolved oxygen to form silicon dioxide (SiO₂), which floats into the slag, resulting in cleaner, denser steel. For high-strength low-alloy (HSLA) steels, the silicon also acts as a solid-solution strengthener. The choice between FeSi75 and FeSi72 here often depends on cost-efficiency; FeSi72 can achieve similar deoxidation results at a lower cost per ton of steel.

For the Foundry Industry (Inoculation):

In the production of ductile and gray iron, ferrosilicon is added to the molten iron just before casting. This process, known as inoculation, promotes the formation of graphite, preventing the formation of hard, brittle carbides (chill) and improving machinability. The minor elements in ferrosilicon, such as aluminum and calcium (as detailed in our composition table), play a crucial role in the nucleation process. Our standard FeSi72 grade is particularly valued in foundries for its consistent inoculation effect.

For Magnesium Smelting (Reducing Agent):

In the Pidgeon process, ferrosilicon (typically FeSi75) is used as a reducing agent. The silicon reacts with magnesium oxide in calcined dolomite under high temperature and vacuum to produce magnesium vapor. For this application, consistent reactivity and controlled impurity levels are critical for maximizing magnesium yield.

FeSi75 FeSi75

FAQ

Q: How do I choose the right ferrosilicon grade for my application?
A: The best choice depends on your specific process. For basic deoxidation in carbon steel, our FeSi72 offers excellent cost-efficiency. For producing electrical steels or when you need a more powerful deoxidation effect, FeSi75 is the standard. For foundry inoculation, the aluminum content is a key factor. Our technical team can review your requirements and help you select the optimal grade (e.g., FeSi75Al0.5 for high-quality ductile iron vs. FeSi75Al1.5 for general gray iron).

Q: Can you guarantee the consistency of size between shipments?
A: Absolutely. We understand that inconsistent sizing can cause feeding problems in your furnaces or injection systems. Our crushing and screening process is precisely controlled, and we can provide a sieve analysis report with your shipment to verify the size distribution (e.g., 10-50mm, 90% min) meets our agreed specifications.

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