Casting iron is an alloy of iron that contains around 2 to 4 percent of carbon. It also includes impurities like Sulphur and phosphorus. It also contains variable amounts of silicon and manganese.
Firstly, by the help of blast furnace, the iron ore is reduced. Then the liquid iron is cast and hardened as crude ingots. This form is known as pigs. After that, Pigs are re-melted to make different desired products. It is melted along with scrap and other alloying elements in cupola furnaces and then are re-casted into desired shapes.
Casting iron are of two types, white iron and gray iron. Gray iron contains more of the Sulphur which makes it lesser hard then the white iron. The silicon factor makes the gray iron Machin able than the white iron.
Malleable casting iron was produced by France in 18th century. It was produced by pro longed heating. This casting iron is not used widely nowadays. However, the ductile casting iron is used a lot nowadays. It was produced by Americans and British in 19th century. This ductile casting iron is used in many automobile industries along side sand casting processes. It is used in making gears, dies and many other machinery parts.