Finite element method-based 3-D heat transfer model for GTAW of Ti-6Al-4V tailor-welded blanks

The selection of the heat source model plays a significant role in numerical modelling of the GTAW process for achieving the accurate weld pool geometry. The present work involves the development of a finite element method (FEM) based 3-D heat transfer model to analyse the GTAW of Ti-6Al-4V TWB. Initially, the weld pool width for bead-on-plate GTAW was analysed using the Goldak’s double ellipsoidal heat source (DEHS) and the Avocado-shaped heat source (ASHS) models. The efficiency of each model was compared with the experimental data from the literature for three levels of welding speed and current. It was found that the ASHS model was more efficient for high-speed welding conditions, while the DEHS model provided accurate results for low-speed welding. The most accurate heat source was selected to generate the heat transfer model for GTAW of TWB with varying fillet geometries (convex, concave, and flat). The predicted weld pool geometry for these different fillets was compared with the experimental results. Further, the effect of changing the thickness ratio of the TWBs on the tensile strength of the Ti-6Al-4 V TWB was also computed and examined. The analysis aimed to understand how modifications in the thickness ratio affected the strength of the TWBs.