To the group of inoculated cast irons belongs so-called ductile iron, which is characterized by a high degree of ductility. As with Grey Cast Iron, there are many grades of Ductile Iron offering varying degrees of tensile strength and elongation. The various grades are achieved by a combination of aluminum additives and heat treatment.

Ductile Iron is very easily machined and machining allowances are able to be kept to a minimum.