High-carbon silicon, also known as silicon carbon alloy, is a composite alloy that combines deoxidation and carbon enrichment. Its grade "6517" indicates approximately 65% silicon (Si) and 17% carbon (C).

Compared to ordinary ferrosilicon, high-carbon silicon has two unique advantages:

It can enrich carbon: FeSi alloy only deoxidizes, while hc silicon can simultaneously add carbon, saving a step in the process.

It can increase temperature: The carbon silicon alloy reaction is exothermic; adding it can increase the temperature of molten steel, reducing power consumption.

Therefore, if your steelmaking requires both deoxidation and carbon enrichment, high carbon silicon is a more cost-effective choice than "ferrosilicon + carbon enrichment agent".

high-carbon silicon

Chemical composition and selection guidelines

Brand	Silicon(Si)	Carbon(C)	Who is it suitable for?
6517	~65%	~17%	The most versatile grade, deoxidizing and carbonizing, offering the best cost-performance ratio.
6520	~65%	~20%	Higher carbon content, suitable for steel grades with high carbon content requirements.
6815	~68%	~15%	Higher silicon content, suitable for steel grades with high deoxidation requirements.

high carbon silicon 6517 is the most widely used and mature grade on the market. The 6517 we supply has a stable silicon content of around 65%, a stable carbon content of around 17%, and impurities such as iron, aluminum, phosphorus, and sulfur are controlled within reasonable ranges.

How to choose the size?

10-50mm lumps: Added during tapping in electric furnaces and converters; easy to add, no smoke.

3-10mm particles: Used in small furnaces or as an inoculant; melts quickly.

0-3mm fine powder: Used for cored wire or powder coating.

High carbon silicon

Product uses?

1. Steelmaking Deoxidation + Carburization (Most Common Application)

High carbon silicon is added to the ladle during steel tapping from a converter or electric furnace, completing deoxidation and carburization in one step.

Dosage: 2-5 kg per ton of steel, depending on the steel grade and target composition.

Compared to "ferrosilicon + carburizer," where are the savings? The silicon and carbon in high-carbon silicon are fused together, resulting in a simultaneous reaction and avoiding the problem of "carburization before siliconization." Moreover, it's cheaper than buying ferrosilicon and carburizer separately.

2. Inoculant in Foundries

Adding high-carbon silicon to gray iron or ductile iron production can promote graphitization and reduce white cast iron. Carbon also improves the fluidity of molten iron.

Recommended size: 3-10mm particles

Dosage: 0.3%-0.8% of molten iron

3. Replaces part of ferrosilicon and recarburizing agent, reducing costs

Some steel mills have calculated that using 1 ton of high-carbon silicon 6517 can replace approximately 0.8 tons of 75 ferrosilicon + 0.3 tons of recarburizing agent, resulting in a comprehensive cost saving of 5%-10%.

4. Smelting high-carbon steel and spring steel

These types of steel have a high carbon content; using high-carbon silicon for recarburizing is more convenient than using low-silicon ferrosilicon with a recarburizing agent.

High Carbon Silicon 6517

What are the advantages of high carbon silicon 6517 over "ferrosilicon +Carbonizer"?

Comparison Items	Ferrosilicon + Carburizer	High-carbon silicon 6517	Advantages of high-carbon silicon
Number of Feedings	Two applications (one for ferrosilicon, one for carburizer)	One-time reaction	Saves labor and time
Ingredient Uniformity	Adding silicon and carbon separately can lead to uneven mixing.	Silicon and carbon are fused together and react simultaneously	More stable steel composition
Yield	Silicon approximately 90%, carbon approximately 80%	Silicon approximately 85%, carbon approximately 85%	Higher carbon recovery rate
Overall Cost	Benchmark	5%-10% lower	Saves money

In short: If your steel requires both deoxidation and carbonization, high carbon silicon is a more economical choice.

high-carbon silicon

FAQ

Q: What's the difference between high-carbon silicon and silicon-manganese alloy?

A: Silicon-manganese alloy (SiMn) is silicon + manganese, mainly used for manganese addition. High-carbon silicon is silicon + carbon, mainly used for deoxidation and carbon addition. Use silicon-manganese alloy if you need manganese addition, and high-carbon silicon if you need carbon addition.

Q: What is the carbon recovery rate of high-carbon silicon?

A: Generally 85%-90%, slightly higher than adding a carbon additive alone (80%-85%). This is because the carbon in high-carbon silicon melts together with the silicon, making it less prone to oxidation and burning.

Q: Is the quality of your 6517 consistent between batches?

A: Consistency is key. We test every batch before shipment to ensure silicon content is between 63%-67% and carbon content is between 16%-18%. A test report is included with the shipment, and you can also conduct your own random checks.

Q: What's the price difference between 10-50mm blocks and 3-10mm granules?

A: Granules are a bit more expensive than blocks because they involve an additional crushing and screening process. For large furnaces and those that are easy to feed, blocks are sufficient; for small furnaces or those used to produce inoculants, granules are more suitable.

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