Residuaalijännite

Residuaalijännite, also known as residual stress, refers to stresses that remain within a solid material after the original applied load has been removed or after manufacturing processes such as welding, casting, or machining. These internal stresses are not caused by external forces acting on the object at the time of measurement. They exist because of the material's response to internal or external forces during its creation or alteration.

Residual stresses can be tensile (stretching) or compressive (squeezing). Tensile residual stresses are generally considered detrimental as they can reduce the material's fatigue life and increase susceptibility to stress corrosion cracking. Conversely, compressive residual stresses can be beneficial, enhancing a material's resistance to fatigue and cracking.

The presence and magnitude of residual stresses depend on factors like the material's properties, the manufacturing process employed, and any subsequent treatments. For instance, heat treatment processes like quenching can induce significant residual stresses. Similarly, plastic deformation, whether intentional (like shot peening) or unintentional, can lead to their formation.

Understanding and controlling residual stresses is crucial in many engineering applications. Techniques such as X-ray diffraction, neutron diffraction, and ultrasonic testing are used to measure residual stress. Depending on the application, residual stresses can be intentionally introduced or deliberately relieved to improve the performance and durability of manufactured components.