2. Grey cast iron

2.1 Grey cast iron structure

Grey cast irons are characterized by the presence of carbon in the form of graphite. These cast irons are often analyzed using the stable iron-graphite diagram, provided the cast iron contains graphitizing elements such as silicon, and the casting temperature is sufficiently high. The latter favors silica reduction and silicon dissolution in the liquid cast iron, especially when cooling is slow. The transition from the stable to the metastable diagram is observed as the temperature decreases, rendering graphitization factors ineffective. Depending on composition, gray cast iron can adopt a variety of structures, including :

• cementite + perlite + flake graphite ;

• perlite + flake graphite...