TIG Welding of Ti Alloys with In-Process Monitoring

Titanium alloys have found increased applications in various industrial sectors. One of the critical issues in quality control is the weld penetration during welding. In the present paper, tungsten inert gas (TIG) welding of Ti-6Al-4V alloy with and without an activating flux was conducted. The effect of the activating flux on Ti alloy welding was investigated. A data acquisition system was used to monitor the welding current and voltage signals during welding. These signals were then correlated to the weld penetration information. It was found that by applying the activating flux on the Ti-6Al-4V alloy surface, weld penetration increases. The amount of the activating flux pasted in the surface determines the penetration capability. Results from monitoring of the welding current and voltage signals indicate that there is a clear correlation between the signals and the weld penetration. Therefore, process monitoring can provide an effective way to assess the consistency of the weld penetration and thus the quality of the welds.