Secondary Stress Relaxation
The time-dependent reduction of residual stresses through thermally activated creep processes at elevated temperatures. This serves to maintain the dimensional stability of highly stressed components.
Secondary stress relaxation happens when a component under load is brought to high temperature. The internal stresses then slowly reduce through creep processes. In welding, this means: if you do a heat treatment after welding, the residual stresses in the structure can be reduced. That's good because the part is then less stressed and less prone to distortion. But be careful: if you do it wrong, i.e., too fast or too hot, the material can also lose strength or new stresses can form. It's important to let the cooling run controlled and not quench with water.