Cast iron

is an iron-carbon alloy containing at least 2% C and other alloy components, notable silicon. The main types include “grey cast iron” (cast iron with laminar graphite) and cast iron with nodular graphite (nodular cast iron), as well as grey cast iron with vermicular graphite, which all have a grey break surface. Tempered cast iron and hard cast iron solidify with a white appearance, and usu- ally have a white break surface.