DEVELOPING A NUMERICAL MODEL TO OPTIMISE THE LASER-BEAM-WELDING PARAMETERS FOR JOINING TITANIUM TUBES

In this work Nd:YAG laser beam welding (LBW), which requires a low heat input, was applied to join grade-2 titanium tubes. The pulse duration and pulse energy were varied according to a two-factor three-level central composite face-centred (CCFC) design to join grade-2 titanium tubes. A numerical model was developed to correlate LBW process parameters and ultimate tensile strength (UTS). Validation of the developed model was done using the analysis of variance. Pulse duration has a more significant impact compared to pulse energy. The highest and lowest values of each process parameter produced a weak UTS, which was less than 338 MPa. The change in the UTS for each process parameter was analysed with metallurgical studies of the joints. Optimised process parameters for improved UTS were identified and reported.