Measurement of residual deformations induced by high temperature load

摘要

Validation of models introduced to simulate the thermo-mechanical consequences of phase transformations in the Heat Affected Zone (H.A.Z.) during welding is a difficult task because of the multiple effects that take place such as heat transfer and the convection of the melting zone. There is also a tridimensionnality induced by the geometry of the pieces to be welded and by the melting zone and displacement of the heat source. This work treats the development of a specific device to validate thermo-mechanical models describing the H.A.Z.. All the "parasitic phenomena" that occur in reality do not take place under conditions for the wanted validation: there is no melting zone and the problem is axisymmetric. However, all thermo-mechanical consequences of phase transformations occur. Many measurement are taken to validate each step of the simulations: thermal, metallurgical and mechanical. An original software for the strain field measurement has been developed to high temperature measurement. This software used the correlation principle and is limited nowadays to the plane surface measurement. This method is particularly well adapted to measure small deformations with high gradients. This new high temperature measurement method without contact can be another tool for validating numerical simulations of the Heat Affected Zone during welding.