Spannungsfreiglühen

Spannungsfreiglühen, also known as stress relieving or annealing, is a heat treatment process used to reduce internal stresses within a metal. These stresses can arise from various manufacturing operations such as welding, casting, forging, machining, or cold working. If left unaddressed, these residual stresses can lead to distortion, warping, or premature failure of the component during subsequent use.

The process involves heating the metal to a specific temperature, holding it there for a predetermined period, and then cooling it slowly. The temperature and time are critical parameters that depend on the type of metal, its composition, and the magnitude of the residual stresses. The heating is done in a controlled atmosphere to prevent oxidation or decarburization of the metal surface.

During the holding phase, the metal atoms gain enough energy to rearrange themselves, allowing the internal stresses to dissipate. The slow cooling is essential to avoid reintroducing new stresses into the material as it cools down. In some cases, the cooling rate might be faster than a full anneal but slower than a normal cooling rate to achieve the desired stress relief without significantly altering the mechanical properties like hardness or strength.

Spannungsfreiglühen is a widely used technique across many industries, including automotive, aerospace, and heavy machinery, to improve the dimensional stability and service life of metal components. It is a cost-effective method to enhance the reliability and performance of manufactured parts.