ABSTRACT
The knowledge of the anisotropic and heterogeneous behaviour of the material is the key point for understanding ultrasonic testing. In the case of austenitic stainless steel multipass welds, there was no exact knowledge. The succession of passes and complex solidification processes makes the modelling of the resulting grain orientation difficult. The MINA model allows such a description. Coupling this model with the new propagation code ATHENA permits a very good understanding of the propagation of elastic waves in this kind of complex media. After discussing the existing models of grains orientations for multipass welds, we show how the new MINA model allows to simulate the anisotropic heterogeneous structure in a more realistic manner. We introduce the simulated grains structure and the real one, obtained by macrographs, into the ATHENA propagation code. We obtain a very good correlation between the two simulated propagations. A first experimental application is also successful. We show in a quantitative and qualitative way that the modelling results are close to the experimental measurements on a thick austenitic weld.
