What is Hardening & Tempering?

Hardening and Tempering is used to produce the optimum combination of hardness, strength and toughness in most commercially available steels.

By heating the material to a temperature in excess of 780°C and subsequently cooling it quickly, the material is hardened.

Components may be quenched in oil, fast quenching oils are available for deeper hardening. Alternatively, a molten salt quench (180ºC - 400ºC martemper) may be used to minimise distortion as appropriate.

Subsequently, uniform tempering is carried out to reduce the hardness and increase the toughness, this is undertaken using electric air circulating pit furnaces.

Benefits

Scaling and de-carburization are eliminated using endothermic atmospheres with oxygen probe control on pit and sealed quench furnaces. Components up to 1.78m long can be treated using special jigging to minimise distortion.

Deep-freezing of components is available, if necessary. This transforms the structure and prepares components for working in cold environments. A stress relieving operation should be carried out after deep-freezing.

Typical Materials

Hardening and Tempering is carried out mainly to medium carbon, alloy or tool and die steels. e.g. 080M40, 817M40, 709M40, O1, D2, D3 etc.