What Is Ferro Silicon 70 (FeSi70)?

Definition and Role of FeSi70 in Metallurgy

Ferro Silicon 70 (FeSi70) is a silicon–iron ferroalloy containing approximately 70 % silicon by weight, with the balance mainly iron and small amounts of unavoidable impurities. It belongs to the family of FeSiXX alloys, where "XX" denotes the nominal silicon percentage.

Attribute	Description
Type	Binary ferroalloy (Si–Fe)
Si content	~68–72 % (nominal 70 %)
Fe content	Balance (~28–32 %)
Main impurities	Al (≤ 2 %), C (≤ 0.2 %), P (≤ 0.05 %), S (≤ 0.04 %)
Form	Lump (10–80 mm), crushed, granulated, or powder
Melting point	~1230–1290 °C (varies with exact composition)
Production method	Carbothermic reduction of quartz (SiO₂) with coke and iron in electric arc furnace

Key Functions in Metallurgy

Deoxidizer in steelmaking: Silicon reacts with oxygen to form SiO₂, removing dissolved O from molten steel.

Alloying element: Increases strength, hardness, and magnetic permeability of steel.

Inoculant/Nodulizer aid in cast iron: Promotes graphite formation and refines grain structure.

Reducing agent in non‑ferrous metal production.

FeSi70 is selected when a lower silicon addition is sufficient, offering economic advantages for applications where high Si content (e.g., FeSi75, FeSi90) is unnecessary or would overshoot target chemistry.

What Is the Chemical Composition of FeSi70 (Typical Si, Fe, and Impurity Levels)?

Typical Elemental Breakdown and Quality Standards

The chemical composition of Ferro Silicon 70 varies slightly by producer and standard, but typical guaranteed ranges are:

Element	Typical Content (wt%)	Standard Limits (example: Chinese GB/T 2272)
Silicon (Si)	68–72 (nominal 70)	68–72 (FeSi70 grade)
Iron (Fe)	Balance	Remainder
Aluminum (Al)	≤ 1.5–2.0	≤ 2.0
Carbon (C)	≤ 0.1–0.2	≤ 0.2
Phosphorus (P)	≤ 0.04–0.06	≤ 0.05
Sulfur (S)	≤ 0.02–0.04	≤ 0.04
Calcium (Ca)	Trace (≤ 0.5)	-

Notes

Si range: "70" denotes nominalSi content; actual guaranteed range is typically 68–72 % depending on grade.

Aluminum: Lower‑Al grades are available for steelmaking where aluminum would be detrimental.

Size: Lump sizes (10–80 mm) suit furnace charging; smaller sizes (crushed/granules/powder) for ladle or stream treatment.

Certification: Each batch should come with a Certificate of Analysis (CoA) confirming compliance with the chosen standard.

Summary Table

Question	Answer
What is Ferro Silicon 70 (FeSi70)?	A ferroalloy with ~70 % Si, used as a deoxidizer and alloying additive in steel and cast iron production.
Chemical composition of FeSi70	Si: 68–72 %, Fe: balance, Al ≤ 2 %, C ≤ 0.2 %, P ≤ 0.05 %, S ≤ 0.04 %.

Ferrosilicon FAQ

China Metallurgy Application Ferro Silicon / Ferrosilicon for Pure Ferro Silicon 75% for Steel and Iron Industry at Competitive Prices

Q: What is Ferro Silicon 70 (FeSi70)?
A: An iron–silicon alloy with ~70% Si, used for deoxidation and alloying in general steelmaking and foundries.

Q: Chemical composition of FeSi70 (typical Si, Fe, and impurity levels)?
A: ~68–72% Si, balance Fe, impurities: Al ≤ 2%, Ca ≤ 1%, C ≤ 0.2%, P ≤ 0.04%, S ≤ 0.02%.

Q: Is FeSi70 a recognized industrial grade? ASTM/GB standards?
A: Not in ASTM A1006; covered in GB/T 2272 (China) and ISO 5448 as a medium‑Si grade.

Q: Silicon content range for FeSi70 (e.g., 68–72%)?
A: Typically 68–72% Si, nominal 70%.

Q: Difference between FeSi70 and FeSi72 (Si content, cost, deoxidation efficiency)?
A: FeSi70 lower Si, lower cost, slightly less efficient deoxidation than FeSi72.

Visit https://www.metal-alloy.com/ to learn more about the product. If you would like to learn more about the product price or are interested in purchasing, please email market@zanewmetal.com. We will get back to you as soon as we see your message.

Get a Quote Today

Iron Silicon Alloy With 75 Silicon Silver Grey Powder For High Strength Alloy Steel Making

🏭 Why Choose ZhenAn?

We understand the common pain points in Ferro Silicon sourcing today:
•High local cost and unstable supply
•Long lead times affecting project schedules
•Incomplete product ranges
•Slow communication and lack of follow-up

We Help Solve These Problems With:
✅ Large stock ready for fast delivery
✅ One-stop sourcing for Ferro Silicon, silicon metal, Silicon Metal Powder , and more
✅ Strict quality control with international standards
✅ Experienced sales team with fast response and clear communication

We'd love to learn more about your needs and offer you competitive prices and efficient service.

one-stop solution

professional team

high quality

What Is Ferro Silicon 70 (FeSi70)?