Ferrosilicon 75 (FeSi75) is one of the most widely used alloy materials in steel plants and foundries. Many buyers know that it is a deoxidizer, but its role actually goes far beyond simply "removing oxygen." Below are a few questions that overseas users often raise when trying to understand how FeSi75 works in real production.
Industry Q&A: How Is Ferrosilicon 75 Used in Steelmaking and Foundries?
Q1: What exactly does FeSi75 do during steelmaking?
The first and most essential function of FeSi75 is . When molten steel contains oxygen, it forms unwanted oxides that weaken the material and cause defects. FeSi75 reacts quickly with oxygen and helps clean the steel.
Compared with lower-grade alloys, FeSi75 reacts more efficiently, producing fewer inclusions and improving steel quality.
Besides deoxidation, FeSi75 also contributes to . Silicon strengthens steel and enhances properties such as elasticity, hardness, and resistance to oxidation. This makes FeSi75 an important additive for steel grades that require stable mechanical performance.
Q2: Why do foundries also rely heavily on FeSi75?
In casting operations, FeSi75 plays a slightly different but equally important role. Silicon improves fluidity in molten metal, making cast products form more smoothly in molds. It also affects the structure of cast metals-particularly in cast iron-where the addition of silicon helps control graphite formation.
In short, foundries use FeSi75 mainly to achieve:
Even small changes in silicon content can affect the outcome of cast products, so FeSi75 is considered a reliable and predictable additive.
Q3: Why is FeSi75 preferred over FeSi72 in certain steel grades?
Steel mills that produce specialty steel, alloy steel, or steel with strict impurity control usually choose FeSi75 because of its .
The difference of a few percentage points in silicon content might seem minor, but in large-scale industrial processes, it can significantly influence consistency and final performance.
Some steel grades, especially those requiring high strength or clean inclusions, benefit from the more stable output provided by FeSi75. This is why mills producing higher-grade steel often make FeSi75 their standard choice.
Q4: How do plants typically add FeSi75 during production?
Adding FeSi75 in batches
Using fine-size FeSi75
to fine-tune the silicon content
Smaller grain sizes (like 0–3mm or 1–5mm) are commonly used in continuous casting or secondary refining because they melt quickly. Larger sizes (10–50mm or 10–100mm) are more typical for blast furnace or electric arc furnace operations.
The key is achieving an even distribution and predictable silicon recovery.
Q5: What are the main benefits of using FeSi75 instead of other deoxidizers?
While many deoxidizing materials exist, FeSi75 is popular because it can perform multiple functions at once:
- removes oxygen efficiently
- enhances steel performance
- consistent melting and predictable recovery
- offers good performance relative to price
- the supply chain for FeSi75 is mature and stable
Because of this combination, many steel plants consider FeSi75 a "core" material in their daily production.
FeSi75 to steel mills and foundries in different regions, and most customers care about stability-both in silicon content and impurity levels. Our material usually comes with consistent grain size and reliable chemical composition, which helps reduce variation during production. If you're checking current FOB prices, available sizes, or the best option for your specific steel grade, you can let us know. We're always glad to share recent data and help you choose the grade more confidently.
