spenningssprøhet

Spenningssprøhet, also known as stress corrosion cracking (SCC), is a degradation mechanism in materials that occurs when a susceptible material is exposed to a corrosive environment under tensile stress. It is a complex phenomenon that can lead to the premature failure of components, often without significant prior warning. The combination of tensile stress, a corrosive environment, and a susceptible material is essential for spenningssprøhet to occur. The stress can be applied externally or be residual stress remaining from manufacturing processes like welding or heat treatment. The corrosive environment can vary widely depending on the material and application, ranging from water and chlorides to specific gases.

The mechanism typically involves the initiation of a small crack at the surface of the material, which then propagates into the bulk material. This propagation is driven by the synergistic effect of the corrosive environment and the applied stress. Various mechanisms have been proposed for crack growth, including anodic dissolution, hydrogen embrittlement, and film rupture. The rate of crack growth can be significantly influenced by the magnitude of the applied stress, the concentration and type of corrosive species, and the temperature.

Spenningssprøhet is a concern in a wide range of industries, including aerospace, chemical processing, oil and gas, and nuclear power. Materials susceptible to spenningssprøhet include certain stainless steels, aluminum alloys, titanium alloys, and polymers. Preventing spenningssprøhet involves careful material selection, controlling residual stresses through proper manufacturing and post-processing, and protecting the material from the corrosive environment. This can involve coatings, cathodic protection, or process modifications to eliminate or reduce the aggressive components in the environment.