Study of high frequency pulsed arc on molten pool thermal properties of Ti-6Al-4V

Infrared thermal observation and thermocouple temperature measurement of molten pool were carried out synchronously with Ti-6Al-4V plates (h = 5 mm). The molten pool surface emissivity was detected, and the non-contact temperature monitoring was calibrated by thermocouple. The temperature distribution was analyzed with the different parameters. The results indicated that the surface emissivity reduced from 0.65 to 0.22. Meanwhile, compared with conventional GTAW (C-GTAW), the maximum surface temperature of molten pool increased by 146K at least with extinguishing arc, and it decreased rapidly within a short distance. By contrast, the external diffusion of high temperature region under ultra-high frequency pulsed GTAW (UHFP-GTAW) decreased by 12.97% to 16.83% (50 A), 2.62% to 9.28% (60 A), and 0.57% to 6.63% (80 A).