Thermal Stress Relieving is a vital process for ensuring that components are stress free before being put into service.
 
A component acquires stresses from the work that is done to it, most commonly welding stress, machining stress and bending stress. 
If these stresses are not released then the component can crack or move during its working life.

Stress Relieving is a non-metallurgical process that is a process carried out without any metallurgical change in structure occurring in the base material. The Stress Relieving parameters of a component will therefore be governed by the material from which it is made.