Ferroalloys

Ferroalloys are iron-based alloys that contain one or more elements other than iron and are used to introduce those elements into steel and cast iron during production. They are produced specifically to supply alloying elements such as chromium, manganese, silicon, vanadium, tungsten, molybdenum, boron, and nickel in controlled amounts, while remaining compatible with the iron matrix.

Production and forms: Ferroalloys are produced in specialized furnaces, typically electric arc furnaces or basic oxygen furnaces, by reducing oxide ores with carbon or by alloying pure metals with iron. The resulting ferroalloy is then added to molten steel or iron in controlled quantities. They are commonly sold as lumps, pellets, briquettes, or powders.

Common types: Ferrochromium (Cr), ferromanganese (Mn, often with silicon), ferrosilicon (Si), ferrovanadium (V), ferrotungsten (W), ferroboron (B), ferromolybdenum (Mo), and ferrotitanium (Ti). Complex ferroalloys combine several elements for specific steel grades, such as stainless steels and high-strength structural steels.

Uses and effects: In steelmaking, ferroalloys serve as deoxidizers and alloying agents. Silicon and manganese deoxidize and help balance sulfur and phosphorus; chromium, vanadium, molybdenum, tungsten, and nickel impart strength, hardness, wear resistance, and, in some cases, corrosion resistance. Boron, in small quantities, can increase hardenability. Ferrochromium is a primary source of chromium for stainless steel production.

Notes: The production and use of ferroalloys are energy-intensive and involve handling of hazardous elements in some grades. They are traded globally and produced in several major steel-producing regions.