The iron obtained from blast furnace contains 4% Carbon and many impurities like S, P, Si, and Mn in smaller amount and this iron is known as pig iron. Pig iron has a high carbon content, usually 3.8–4.7 percent, as well as silica and other dross constituents, making it brittle and unusable as a material except for a few purposes.
Uses of Pig iron
- Pig iron was traditionally transformed into wrought iron in finery forges, puddling furnaces, and, more recently, steel.
- Gray iron can also be made from pig iron. This is done by remelting pig iron with a large volume of steel or scrap iron, removing unnecessary pollutants, adding alloys, and changing the carbon content.
- Some pig iron grades can be used to make ductile iron.
- Modern steel mills and direct-reduction iron plants transfer the molten iron to a ladle for immediate use in the steel making furnaces or cast it into pigs on a pig-casting machine for reuse or resale.
- Stick pigs are developed by modern pig casting machines, which break down into smaller 4–10 kg piglets at discharge.