Definition - What does Stress Relief mean?
Stress relief is a process in which a material is heated to a specific temperature for a specific amount of time to reduce the internal forces acting on the material. The material is then typically cooled at a slow, controlled rate so as to avoid adding any other internal stresses to the material.
Stress in a material can come from mechanical and thermal processes. Stress relief can prevent cracks in welds and unexpected dimensional changes to parts that have been altered mechanically.
Corrosionpedia explains Stress Relief
Materials are heated using a variety of methods during the stress relieving process. Furnace stress relief, resistance stress relief and induction stress relief are all quite common.
It is important to know that during a stress relief process the material's temperature should not raise above its critical temperature. If this happens then many material properties are likely to change. Stress relief is intended to reduce residual stress but not change a material's crystalline structure. The critical temperature is unique for each material.