3 February 2016

What is tempering?

What is the tempering process?

Tempering is a heat treatment process in metallurgy used to increase the toughness of iron-based alloy is mostly performed after hardening. Tempering operation depends on the steel and the tempering temperature.

Purpose of tempering 

  • Adjust the strength, hardness, plasticity and toughness of the workpiece. 
  • Eliminate residual stress during quenching and prevent cracking. 
  • Improve the processability. 

How the tempering process is performed?

  • First of all preheating previously quenched or normalized steel to a temperature below the critical range.
  • Holding it for some time.
  • The cooling process is again performed to obtain the desired mechanical properties. 
The hardness and strength obtained by tempering are depended upon the temperature at which tempering is carried out. If temperatures are high ductility also high, but low strength and hardness. 

This operation is performed on all carbon steels that have been hardened, in order to reduce the brittleness of the metal, so that they can be used effectively in desired applications.

Benefits of tempering 

  • Tempering reduces hardness in material and increases the toughness.
  • Material properties such as hardness/toughness ratio can be adapted to a specific application.