Residuaalijännitettä

Residuaalijännitettä, often translated as residual stress, refers to internal stresses that remain within a material after the original applied forces have been removed. These stresses can arise from a variety of manufacturing processes such as welding, casting, forging, machining, or heat treatment. They can also be induced by mechanical deformation, plastic working, or even environmental factors like temperature changes.

The presence of residual stresses can significantly influence the behavior and performance of a material or component. Tensile residual stresses, for example, can decrease the fatigue life and increase the susceptibility to stress corrosion cracking. Conversely, compressive residual stresses can improve fatigue resistance and inhibit crack propagation. Therefore, understanding and controlling residual stresses is crucial in many engineering applications, particularly in areas where structural integrity and longevity are paramount.

Measuring residual stresses can be achieved through various methods, including destructive techniques like hole drilling and sectioning, and non-destructive techniques such as X-ray diffraction, neutron diffraction, and ultrasonic testing. The distribution and magnitude of residual stresses depend on factors like the material properties, the manufacturing process employed, and the geometry of the component. Managing residual stresses often involves specific post-processing treatments designed to introduce beneficial compressive stresses or reduce detrimental tensile stresses.