Study on weld porosity in Ti-6Al-4V titanium alloy with ultra high frequency pulsed GTAW

The study on weld porosity was carried out with Ti-6Al-4V titanium alloy. The experimental data indicated that the significant porosity elimination can be found with ultra high frequency pulsed GTAW (UHFP-GTAW), no porosity or much less porosities in weld compared with conventional GTAW (C-GTAW). The research focused on influence of arc behavior of UHFP-GTAW to porosity during growth period, detaching period, and escape period respectively. The results showed the benefits for the growing of gas pores nucleus which are pressed, the detaching process of the gas pore with higher surface tension, and decreasing of sensibility of weld porosity when the temperature in the molten pool increased which made less viscosity of the liquid metal and a large escape velocity on the condition of UHFP-GTAW.