Gray Cast Iron
Contain flake graphite. Moderate strength, but good machinability and damping capacity. Cannot be worked (forged, extruded, rolled, etc.).
Malleable Cast Iron
Good ductility, strength, and shock resistance (better fracture toughness at low temperatures than nodular irons) . Moderate machinability. Can be shaped through cold working.
Nodular Cast Iron
Contain nodular graphite. Good ductility and shock resistance. Moderate machinability.