INVESTIGATION AND OPTIMIZATION OF DISK-LASER WELDING OF 1 MM THICK TI-6AL-4V TITANIUM ALLOY SHEETS

Welded Ti-6Al-4V joints are employed in nuclear engineering, civil industries, military and space vehicles. Laser beam welding has been used for welding thanks to its advantages in terms of increase in penetration depth and reduction of possible defects; moreover a smaller grain size in the fused zone is benefited in comparison to either TIG and plasma arc welding, thus providing an increase in the tensile strength of the welded structures. The aim of this work is to develop and test the regression model for a number of crucial responses. The study has been carried out on 1 mm thick Ti-6Al-4V plates; a square butt welding configuration was considered employing a disk-laser source. A three level Box-Behnken experimental design is considered. An optimum condition has been suggested via numerical optimization of the desirability function with proper weights and importance of constraints. Vickers micro hardness testing was conducted to discuss structural changes in fused and heat affected zone.