Stress Relief Annealing

You do stress-relief annealing after welding when you want to get rid of the residual stresses caused by the heat input. You heat the workpiece evenly to a temperature well below the transformation temperature, hold it for a while, and then let it cool slowly and controlled. This allows the structure to relax and the stresses to build down without undesired changes in the material structure. This is important to avoid later distortion or cracks in the construction.