A Comparative Study on Direct and Pulsed Current Micro-plasma Arc Welding of Alloy Ti-6Al-4V

In this project, the sheet of Ti-6Al-4V alloy (annealed) with a thickness of 1 mm was welded with butt joints by means of pulsed current micro-plasma arc welding without using a filler metal. The purpose of this study is to optimize parameters in the event of increasing tensile strength by using pulse current and its comparison with the pulse-free system. Optical microscope and scanning electron microscope were used to investigate the type of phases, microstructure of weld metal, base metal and heat-affected zone. Results illustrated that due to the low thickness of the sheet, the non-use of filler metal in the welding process and the lower heat input of this process, all contributed to a higher cooling rate of the molten pool.