Surface Residual Stress
Residual surface stress is caused by uneven cooling and thermal cycles in additively manufactured parts. It leads to mechanical stresses that often need to be reduced by post-treatments like stress-relief annealing.
Physicochemical mechanism of action
Surface residual stress occurs in additively manufactured parts when certain areas cool faster or slower than others. This leads to uneven stresses within the material structure, especially at the edge. These stresses can build up during cooling and remain.
Metallurgical relevance & risks in welding
Surface residual stress can cause mechanical cracking, distortion, and failure of parts. It increases susceptibility to hot cracking and reduces the service life of components. Additionally, it can hinder welding by creating stress concentrations that make it difficult for the weld to penetrate the metal.
Workshop practice & instructions
To reduce surface residual stress, post-weld heat treatments such as stress relieving should be performed after fabrication. This involves heating the part in a controlled environment to ensure uniform cooling and relaxation. The exact temperature and duration depend on the specific material and part geometry.