Ultrasonic Processing Across Different Phases in Laser Welding of Large Thin-Walled Structures

Abstract

In laser welding applications for large structures like oil storage tanks, ships, automobiles, and high-speed rail, effective post-weld heat treatment is challenging because the structures are large and cannot be disassembled. This results in significant residual welding stress, leading to reduced mechanical properties, shorter fatigue life, and excessive welding deformation, which compromises assembly accuracy. Current studies on ultrasonic field application in thin-walled structures predominantly position the ultrasonic source directly beneath the welding pool. While this approach offers high ultrasonic transfer efficiency and a straightforward physical model, it is impractical for large, enclosed, or non-transparent structures, where access from behind is limited and weld protection is required. This paper proposes a novel process model that positions the ultrasonic source on the same side as the welding pool, addressing key challenges in practical engineering. Preliminary investigations into critical aspects of this model provide a foundation for further research and potential industrial application.