Induction tempering is a heat treatment process usually performed following a process of induction hardening, atmospheric carburizing, or carbonitriding, in order to achieve the desired ductility, hardness/stiffness ratio.

In order to achieve the desired range of hardness, or to add stiffness to a part while increasing malleability. Induction tempered steel is usually done in furnaces that may have an option for protective gases. The protective gas will keep the surface from oxidizing throughout the process and is mostly used at higher temperatures. A lower frequency achieves results within seconds, as opposed to furnace-tempered applications which usually require hours.

For certain types of steel, holding time in a tempering temperature is very important; extended holding times will be appropriate at higher temperatures. Depending on the steel grade used there is a phenomenon known as tempering frostiness that may arise in specific temperature ranges. Tempering within these temperature intervals should generally be avoided. These areas are shown in a steel suppliers’ catalogue of steels, along with their most appropriate temperatures. Depending on the requirements for hardness induction tempering can be performed on all components, such as bars, joints, and shafts. Tempering improves both material hardness and wear resistance.

Induction Tempering in Industry

Where are induction tempers used? Steel and cast-iron hardening is the most common application for induction heat treating.

Induction tempering is used extensively in the automotive industry for tempering surface-hardened components like shafts, bars, and joints. The tubing and pipe industries also use the process to temper workpieces. It is also a form of case hardening, which can be used on many plates of steel and steel alloys to increase surface layer properties, such as wear resistance and hardness.

Other industry uses include:

  • Tractors and construction machinery
  • Machine tool manufacturing industry
  • Heavy machinery
  • Bearing industry
  • Railway
  • Transportation
  • Oil rigs
  • Metallurgical machinery