Pig iron is an iron-carbon alloy with carbon content exceeding 2%. The carbon content of industrial pig iron is generally 2. 1 1%-4.3%, and contains elements such as C, Si, Mn, S, P, etc. It is the product of smelting iron ore in blast furnace. According to the different forms of carbon in pig iron, it can be divided into steelmaking pig iron, casting pig iron and ductile iron.

Pig iron is hard, wear-resistant and can be cast, but it is fragile and cannot be forged.