| Popis: |
It is often stated that the best heat treatments are those that are not necessary. Clearly, the statement makes sound commercial and technical sense. Efforts are constantly being made by welding technologists and metallurgists to devise justifications for relaxing heat treatment requirements by either modifications to materials or development of welding techniques, which give greater control over the factors, which influence residual stress and structural change. These influences bear even greater significance in welding of complex structures, especially those that would require a localized in situ heat treatment. In such circumstances, heat treatment after welding to reduce residual stresses poses problems of practicality and desirability. The thermal gradients inherent in such an approach can induce further stresses large enough to affect the integrity of the structure. |
