What Are Ferrosilicon 75 And Ferrosilicon 65?

Today's price of ferrosilicon exported from China
Unit: US dollars/ton
product	Brand	Quotation	rise and fall	Remark
Ferrosilicon	72	1020-1040	--	FOB Tianjin Port
Ferrosilicon	75	1100-1120	--	FOB Tianjin Port

What Are Ferrosilicon 75 and Ferrosilicon 65?

Both are ferroalloys​ composed of iron (Fe)​ and silicon (Si), widely used in steelmaking, foundry, and alloying. The numbers 75​ and 65​ indicate the approximate percentage of silicon​ in each alloy:

Grade	Silicon (Si) Content (Nominal)	Iron (Fe) Content (Balance)	Also Known As
Ferrosilicon 75 (FeSi 75)​	72–78% Silicon​	22–28% Iron​	High-silicon ferroalloy
Ferrosilicon 65 (FeSi 65)​	60–67% Silicon​	33–40% Iron​	Medium-silicon ferroalloy

🔹 The key difference​ is the silicon content​ - FeSi 75 has more silicon, making it more powerful for deoxidation and alloying.

 

 Key Differences at a Glance

Feature	Ferrosilicon 75 (FeSi 75)​	Ferrosilicon 65 (FeSi 65)​
Silicon Content​	72–78%​ (Higher)	60–67%​ (Lower)
Iron Content​	22–28%​ (Lower)	33–40%​ (Higher)
Deoxidation Power​	Stronger​ (more Si reacts with oxygen)	Good, but less intense​
Alloying Efficiency​	Higher​ (more silicon for strength, hardness, etc.)	Moderate​
Cost per Ton​	Usually higher​	Usually lower​
Cost per kg of Silicon​	Better value​ (more Si per ton)	Less value​ (less Si per ton)
Typical Use​	Premium steel, ductile iron, electrical steel​	General steel, cost-sensitive foundry work​
Also Called​	FeSi 75, Ferro Silicon 75, Silicon Ferro 75	FeSi 65, Ferro Silicon 65, Silicon Ferro 65

 

 When to Choose Ferrosilicon 75

Choose Ferrosilicon 75​ when you need:

1. High Silicon Efficiency

72–78% silicon​ means more deoxidation power​ (removes oxygen from molten steel or iron).

More silicon also means better alloying​ - improving:

Strength

Hardness

Wear resistance

Corrosion resistance

Magnetic properties​ (especially in electrical steel)

2. Premium Steel & Alloy Production

Ideal for:

Electrical steel​ (transformers, motors) → silicon improves resistivity

Tool steel, spring steel, stainless steel

Alloy steels​ requiring precise silicon content

3. Ductile (Nodular) Iron & Inoculation

FeSi 75​ is widely used to:

Refine graphite structure​ in gray iron

Support nodularization​ (spheroidal graphite) in ductile iron

4. Stronger Deoxidation in Steelmaking

More silicon → faster, more complete reaction with oxygen​ → cleaner steel

5. When Alloy Performance Outweighs Cost

FeSi 75 is more expensive per ton, but you get more active material (silicon)​ per ton → better value for performance

 

Common Applications:

Steel deoxidation

Alloying (high-performance steels)

Ductile iron production

Inoculation of cast iron

Electrical and magnetic steel

 

When to Choose Ferrosilicon 65

Choose Ferrosilicon 65​ when you:

1. Want a More Economical Option

FeSi 65 is usually cheaper per ton​ because it contains less silicon (60–67%)​ and more iron.

2. Are Working on Cost-Sensitive or General Applications

Suitable for:

Basic carbon steel

General foundry work

Large-volume steel production​ where extreme silicon efficiency isn't critical

3. Need Basic Deoxidation & Alloying

FeSi 65 still provides good deoxidation, just not as strong as FeSi 75

Good for general alloying, but with less silicon impact per ton

4. Are Using It as a Secondary or Supplemental Alloy

Can be combined with other materials to meet silicon requirements

 

Common Applications:

General steelmaking

Foundry operations (gray iron, basic castings)

Carbon or low-alloy steel

Budget-conscious production

 

Why Silicon Content Matters

Silicon (Si)​ is the active ingredient​ in Ferrosilicon:

Reacts with oxygen​ → removes it (deoxidation)

Increases strength, hardness, and wear resistance

Controls graphite formation​ in cast iron

Enhances magnetic and electrical properties​ in special steels

👉 The higher the silicon content (e.g., 75%), the more effective the alloy is per ton, even if the cost is slightly higher.

 

Quick Comparison Summary

Criteria	Ferrosilicon 75 (FeSi 75)​	Ferrosilicon 65 (FeSi 65)​
Silicon %​	72–78%​	60–67%​
Iron %​	22–28%​	33–40%​
Cost per Ton​	Higher	Lower
Value per kg of Si​	Better	Lower
Deoxidation Ability​	Stronger	Good
Alloying Efficiency​	Higher	Moderate
Best For​	Premium steel, ductile iron, electrical steel	General steel, cost-sensitive casting
Also Called​	FeSi 75, Ferro Silicon 75	FeSi 65, Ferro Silicon 65

 

 How to Choose: Decision Guide

Choose Ferrosilicon 75​ if you:	Choose Ferrosilicon 65​ if you:
Need high deoxidation & alloying performance​	Need a cost-effective solution​
Are producing high-performance or specialty steel​	Are working with basic or carbon steel​
Are making ductile (nodular) iron​ or need good inoculation​	Have general foundry or casting needs​
Silicon efficiency is critical​	Cost control is more important​
You want faster, more complete reactions in the melt​	You can accept slightly lower reactivity​

 

 Practical Tips

Ferrosilicon 75​ is the global standard​ for deoxidation, inoculation, and alloying​ - especially in FeSi 75 lumps or granules.

Ferrosilicon 65​ is widely used in regions or plants focused on cost efficiency, or where the highest silicon impact isn't required.

Always confirm the exact silicon range​ with your supplier, as actual content may vary slightly by standard or source.

 

Keywords Integrated:

Ferrosilicon, Ferro Silicon, Ferrosilicon 75, Ferrosilicon 65, FeSi 75, FeSi 65, Ferrosilicon Alloy, Fe Silicon, Fesi Ferrosilicon, Silicon Ferro, Silicon, Iron Silicon Alloy, Deoxidation, Alloying, Inoculation, Cast Iron, Steelmaking

 

Conclusion

Ferrosilicon 75 (FeSi 75)​ is the preferred choice​ when you need high silicon content (72–78%)​ for strong deoxidation, premium alloying, and inoculation​ - especially in electrical steel, ductile iron, and high-performance applications.

Ferrosilicon 65 (FeSi 65)​ is a cost-effective alternative​ with good performance, suitable for general steelmaking and foundry work​ where extreme silicon efficiency is not critical.

 

In short:

Use FeSi 75​ for high-end, performance-driven metallurgy.

Use FeSi 65​ for economy and general applications.