How is 'cast iron' different from 'pig iron'?
The iron obtained from blast furnace is known as pig iron. It contains around 4% carbon and many impurities, such as S, P, Si, Mn, in smaller amounts.
Cast iron is obtained by melting pig iron and coke using a hot air blast. It contains a lower amount of carbon (about 3%) than pig iron. Unlike pig iron, cast iron is extremely hard and brittle.