Preliminary reminders
Cast-iron heat treatments: Selection guide

The heat treatments and terminology used for cast irons are similar to those used for steels, but with some particularities: the notion of "hardenability" used for steel metallurgy can be transposed to cast irons, but the high carbon and silicon contents, combined with an appreciable manganese content, give cast irons a relatively high hardenability, so that oil quenching can be substituted for water quenching.

It is essential to note that the carbon content of the austenite before hardening is a function of the austenitizing temperature and, therefore, hardenability will depend not only on the chemical composition of the matrix, but also on the austenitizing conditions.

The presence of silicon leads to the formation of a critical temperature interval during the γ → α transformation, an interval that widens and moves to higher values as...