Utilization of Process Monitoring in Ti Alloy Welding

Abstract

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 was used to weld 8.0-mm thick Ti-6Al-4V alloy plates with and without an activating flux. 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. Results show that by applying the activating flux on the Ti-6Al-4V alloy surface, weld penetration depth increases, while the corresponding weld bead width is reduced. It was also found that various welding conditions, particularly flux thickness, influence the effectiveness of the activating flux. Results from monitoring of the welding current and voltage signals reveal that there is a clear correlation between the signals and the weld penetration. By analyzing the acquired signals, inconsistency in weld penetration can be identified. This demonstrates that process monitoring can provide an effective way to assess the consistency of the weld penetration and thus the quality of the welds.