Cast iron is an iron-carbon alloy with a carbon content of more than 2.11% . It is obtained from industrial pig iron, scrap steel and other steel and its alloy materials through high-temperature melting and casting. In addition to Fe , it also contains other carbon in the cast iron and precipitates in the form of graphite . If the precipitated graphite is in the form of strips, the cast iron is called gray cast iron or gray cast iron, the cast iron in the form of worms is called vermicular graphite cast iron , and the cast iron in the form of flocs is called white cast iron or code iron, and when it is spherical Cast iron is called ductile iron. The chemical composition of nodular cast iron except iron is usually: carbon content of 3.0 to 4.0% , silicon content of 1.8 to 3.2% , total manganese, phosphorus, and sulfur content of no more than 3.0%, and appropriate amounts of rare earth, magnesium and other nodular elements.