Hardening and tempering steels are used for the manufacture of mechanical pieces subjected to high static and dynamic loads and are widely used in the mechanical industry: shafts of any kind, rods, connecting rods, levers etc.
The types of structural steels intended for the hardening and tempering treatment belong to this group.
In the only hardened condition, the steel shows a high hardness with a very low toughness, therefore a subsequent tempering is necessary to eliminate all tensions and brittleness.
By hardening and tempering “the optimal” compromise between toughness and resilience can be achieved.