Grain refinement and high performance of titanium alloy joint using arc-ultrasonic gas tungsten arc welding

Arc-ultrasonic welding technology is one approach for refining the grain structure in titanium alloy welds. This paper reports work in which welds were produced in an alpha-beta titanium alloy under a variety of conditions, including conventional gas tungsten arc welding (GTAW) and arc-ultrasonic GTAW. The results show that arc-ultrasonic energy refined beta grain structure in the weld metal, and improved the fatigue life of weld joints. Ultrasonic energy enhances fluid flow, reduces temperature gradients, and causes a continual high frequency oscillation in the welding pool. These effects are believed to be responsible for refining the solidification structure and improving the performance of titanium weld joints.