Etude des contraintes residuelles dans les joints soudes de turbines hydrauliques.

摘要

An experimental program was carried out in order to establish the global distribution of residual stresses in hydraulic turbine runner welded joints. A better understanding of the distribution of these stresses will make possible to the manufacturer to optimize the design of these joints and, consequently, to increase their performance in service.; Two principal objectives are aim in this project. The first consists in obtaining an overall representation of residual stresses, on the surface, in the welded joints area of hydraulic turbine runners. The second objective consists in evaluating residual stresses inside the welded joint, in a plan of interest for which the residual stresses are likely to contribute to the crack propagation during operation. In order to achieve these objectives, measurements were carried out on hydraulic turbine runners (with partial penetration welded joints) and on T-joint samples (with partial and total penetration welded joints). The samples were fabricated by respecting all the specifications applicable to hydraulic turbine runners; the same material welding process and inspections were carried out. The influence of several variables on the global distribution of residual stresses was studied; in particular the thickness of the plates forming the joint, the welding process (for partial and total penetration welded joints) and the post welded heat treatment. (Abstract shortened by UMI.)