Ferro Silicon Price Today
Live Ferro Silicon rates — formulations available with 15%, 45%, 75% and 90% silicon content.
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View Metalsbuy SiMn Index →Ferro Silicon Overview
Ferro Silicon, an alloy combining Iron and Silicon with Silicon content ranging from 15% to 90%, is vital for creating robust and high-performance materials. With various formulations available (15%, 45%, 75% & 90% Silicon content), Ferro Silicon is tailored to meet specific needs.
Its main job is deoxidation. Silicon has a strong affinity for oxygen, so a Ferro Silicon addition pulls dissolved oxygen out of liquid steel and takes it into the slag, leaving metal that is clean and free of the gas porosity that would otherwise show up in the cast product. It is the standard deoxidiser wherever a separate silicon addition is wanted rather than the combined silicon-and-manganese addition that Silico Manganese provides.
The second use is in cast iron, where Ferro Silicon works as an inoculant and — as a magnesium-bearing variant — as a nodulariser. Inoculation controls how graphite forms as the iron solidifies, which is what separates a sound grey iron casting from a hard, brittle, unmachinable one. Ductile (SG) iron depends on the same family of alloys to turn graphite flakes into nodules.
The third is electrical steel. Silicon raises the electrical resistivity of steel and cuts core loss, which is why transformer and motor laminations are silicon steels. Grades there are decided by the silicon level, and the alloy has to be clean.
Ferro Silicon is made by reducing quartzite with coke and iron in a submerged arc furnace, and it is heavily electricity-intensive — a significant part of its cost is power. Grades are named by silicon content: 70-75% is the common commercial grade, with 15%, 45% and 90% supplied for specific uses. Aluminium is the specification to watch, because it carries into castings and causes pinhole defects.
Grades & Specifications
Ferro Silicon
| Condition | Specs | Details |
|---|---|---|
| Min | Silicon | 70%-75% |
| Max | Carbon | 0.15% |
| Max | Al | 2% |
| Max | Sulphur | 0.05% |
| Max | Phosphorus | 0.05% |
Applications & End Uses
- Deoxidation of carbon, alloy and stainless steels
- Inoculant in grey iron, controlling graphite formation and machinability
- Nodulariser (as magnesium ferro silicon) for ductile / SG iron castings
- Silicon and electrical steels for transformer and motor laminations
- Alloying addition where silicon raises strength and oxidation resistance
- Reducing agent in the production of other ferro alloys and of magnesium
- Welding electrode manufacture
Buying Ferro Silicon: What to Check
Check the aluminium limit if the metal goes into castings
Our standard grade caps aluminium at 2%. In foundry work aluminium carries through and causes pinhole porosity in the casting, so foundries usually want a tighter limit than steel plants do. State the maximum you can accept at the enquiry stage.
Silicon grade is not interchangeable
70-75% is the general commercial grade. 15%, 45% and 90% exist because different processes need different silicon-to-iron ratios and different melting behaviour. Substituting one for another changes both the addition rate and the thermal effect on the melt.
Carbon is already low — keep it that way
Ferro Silicon runs at about 0.15% carbon maximum, which is one reason it is preferred over Silico Manganese in low-carbon and stainless work. Verify the figure on the lot certificate if your grade depends on it.
Size affects recovery more than with other alloys
Silicon is light and oxidises readily. Excessive fines burn off before they can do their work, so recovery drops and the addition becomes unpredictable. Fix the size range and the fines allowance in the order.
Expect power costs to drive the price
Producing Ferro Silicon is among the most electricity-intensive processes in the alloy business. Its price responds to power tariffs and to quartzite and coke costs, so it can move independently of the steel market.
Ferro Silicon — Frequently Asked Questions
What is Ferro Silicon used for?
Mainly as a deoxidiser in steelmaking — silicon strips dissolved oxygen out of liquid steel. It is also used as an inoculant and nodulariser in cast iron, and as the silicon source in electrical steels for transformer and motor cores.
What silicon grades are available?
70-75% silicon is the common commercial grade. Formulations at 15%, 45% and 90% are supplied for applications that need a different silicon-to-iron ratio or different melting behaviour. They are not interchangeable without changing the addition rate.
Why does aluminium content matter in Ferro Silicon?
Aluminium carries through into castings and causes pinhole porosity. Our standard grade caps it at 2%, but foundries usually require a tighter limit than steel plants, so the maximum should be specified when enquiring.
Ferro Silicon or Silico Manganese for deoxidation?
Silico Manganese adds silicon and manganese together and is the economical choice for general carbon steel. Ferro Silicon is used where you want silicon without the manganese, or where the very low carbon content — around 0.15% maximum — matters to the grade.
What is an inoculant, and why does cast iron need one?
An inoculant controls how graphite forms as iron solidifies. Without it the iron can solidify white — hard, brittle and effectively unmachinable. Ferro Silicon inoculation is what produces a sound, machinable grey iron casting.
How is Ferro Silicon produced?
By reducing quartzite with coke and iron in a submerged arc furnace. It is one of the most electricity-intensive alloys to make, so power tariffs are a large part of its cost and a large part of why its price moves.
Why is Ferro Silicon used in electrical steel?
Silicon raises the electrical resistivity of steel, which reduces eddy current losses in a magnetic core. That is why transformer and motor laminations are made from silicon steels rather than plain carbon steel.
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