Tempering is a process which is capable of decreasing or increasing the hardness and strength of steel. It can also increase the toughness of hardened steels, while removing the tensions created in the material revealing the steel with the required hardness.
Tempering can be performed on all hardened components, such as bars, joints and shafts. It is a heating process that optimizes mechanical properties such as toughness and ductility in workpieces that have already been hardened.
The traditional tempering system consists of heating the parts at relatively low
temperatures (typically between 150°C to 500°C, always below the AC1-temperature) for a while and then let them cool slowly.
Tempering process can be divided into three main groups
• Low temperature (160-300°C): used for case hardening components and cold working tool steels. Typically, hardness requirement is around 60 HRC.
• Tempering of spring steels (300-500°C): used for spring steels or similar applications. Typically, hardness requirement is around 45 HRC.
• High temperature (500°C or higher): used for quenched and tempered steels, hot working tool steels and high speed steel. The hardness will vary from 300HB to 65HRC dependent on the material.
• Induction tempering takes less time compared to furnace tempering which takes hours.
• Induction tempering facilitates quality control of individual workpieces.
• Saves floor space and improved environmental conditions.