High carbon ferrosilicon is a brittle, hard, and dense material with a metallic luster. It has a high melting point and is a good conductor of electricity. Its high carbon content gives it a higher heat output than standard ferrosilicon.

High carbon ferrosilicon is primarily used as an additive in the production of steel and cast iron. Its high carbon content makes it useful in the production of specialty steels, such as spring steel and tool steel.

High carbon ferrosilicon is produced in a submerged arc furnace by melting a mixture of iron, silicon, and carbon. The carbon content can be adjusted by varying the amount of carbon in the mixture.