Parts often contain internal stresses (permanent stresses) due to unstable temperature flow during cooling after casting or hot forming, or due to mechanical stresses in the operation. If these internal stresses exceed the elasticity and yield limits of the material, they cause plastic deformation and increase the true yield limit. In addition, if these internal stresses become higher and reach or exceed the breaking stress, they cause fracture with plastic deformation. Stress relief annealing is applied in order to eliminate the stresses formed in this way.

The purposes of stress relief annealing are:

- Preventing the part from warping or cracking by relieving internal stresses
- Develop dimensional stability
- Reducing the stresses of the welded or cold worked part.

In stress relief annealing, the parts are heated slowly to reach the region between 550-630°C, where they are annealed for approximately 4 hours. Cooling is done very slowly so that all parts of the part always remain at the same temperature. Stress relief annealing; Applied before machining hot forged and cast materials, before surface cleaning of parts with narrow tolerance ranges, and on welded parts