Surface Compressive Residual Stress
Surface compressive residual stress is a compressive stress created by mechanical surface treatments that prevents cracking. It increases the fatigue strength under cyclic loading.
Physicochemical mechanism of action
Mechanical surface treatments such as polishing or rolling deform the surface of a material. This creates microscopic stresses that turn into compressive residual stresses. These stresses prevent cracks from forming and improve the mechanical strength of the surface.
Metallurgical relevance & risks in welding
Surface compressive residual stresses can be destroyed by careless welding, which can lead to cracking. It is important to treat the weld so that the stress is preserved or only minimally affected.
Workshop practice & instructions
To preserve surface compressive residual stresses when welding, the following measures should be taken:
• Use careful surface treatment before welding.
• Keep the weld under low stress and avoid overheating.
• Use suitable shielding agents to protect the material during welding.