Visualizing the influence of process parameters on fusion hole behavior in tungsten inert gas welding of thin plates with reserved gaps

Abstract

In one-side welding with back-formation with a reserved gap, the weld quality largely depends on the stability of the fusion hole. Therefore, the influence of welding process parameters on fusion hole behavior must be analyzed to realize the quality control for this type of welding. In this study, a low-cost dual camera visual sensing system is designed to conduct real-time synchronous monitoring of backside and topside fusion hole behavior and obtain clear images of the backside and topside of a fusion hole. A series of wire-filling tungsten inert gas welding tests with a reserved gap for 3 mm thick 304 stainless-steel test pieces were performed. According to the fusion hole behavior, the welding process was divided into three stages: blind fusion hole stage, fusion hole growth stage and stable fusion hole stage. Moreover, the influence law of the main process parameters (i.e. welding current, welding speed and reserved gap) on fusion hole behavior was explored. The results lay a solid foundation for fusion hole control and optimization in one-side welding with back-formation with a reserved gap.