Residual Stress Superposition
Residual stresses are pre-existing stresses in materials that arise from manufacturing processes. These superimpose with load stresses and can affect fatigue life.
Physical-Chemical Mechanism of Action
Residual stresses are stresses that arise in materials during manufacturing, such as during welding, forging, or pressing. These stresses superimpose with stresses caused by loads (load stresses) on the surface of the component.
Metallurgical Relevance & Risks in Welding
The superimposition of residual and load stresses can shorten the fatigue life of a component. Tensile residual stresses, which arise from the superimposition, increase the mean stress and make the material susceptible to fatigue fractures. Compressive residual stresses, however, can increase service life by distributing loads evenly over the entire material.
Workshop Practice & Instructions
To minimize the negative effects of residual stresses, careful attention should be paid during welding to avoid introducing additional stresses. This can be achieved through proper pre-treatment of the material and controlled cooling. For complex components, it is advisable to measure residual stresses and, if necessary, neutralize them.