Computational Modeling of Thermo-Metallurgical Behavior During the TIG Welding Process

Welding is widely used in the aerospace, naval and automotive industries. Since high temperatures are involved in this process, solid state metallurgical changes are expected. These metallurgical changes can induce deformations and residual stresses in welded parts. The objective of this work is to develop a finite element calculation code, under the MATLAB environment, to predict the evolution of the various metallurgical transformations during TIG welding of C50 steel plates. In the proposed calculation procedure, we used Leblond’s equation and Waeckel’s model to characterize the metallurgical transformations during respectively heating and cooling stage. We also taken into account the effect of austenitic grain size on metallurgical transformations evolution. Thermal properties are introduced according temperature and phase proportions present during welding operation. Simulation results show that the metallurgical structure in the heat affected zone (HAZ) is largely related to welding thermal power and the plate preheating temperature. We compared simulation results to experimental measurements and the efficiency of the developed computational code was confirmed.