4. Enhanced mechanical properties

4.1 Quenching and tempering

The purpose of quenching and tempering cast irons is not simply to regulate hardness, but rather to establish the best compromise between machinability, wear resistance and mechanical characteristics (strength, resilience, plasticity) of statically or dynamically highly stressed parts: it is this set of properties that we refer to here under the general term of toughness. Figure illustrates, for example, the evolution of mechanical properties after quenching and tempering of moderately alloyed gray cast iron.

For the treatment of lamellar or white graphite cast irons, water quenching or even oil quenching is generally...