Investigation on dynamic behaviors of bubble evolution in underwater wet flux-cored arc welding

Bubble evolution behavior has a significant effect on the process stability and weld joint quality in underwater wet flux-cored arc welding (FCAW). In this study the visual sensing of bubble evolution behaviors based on high-speed camera method have been explored in attempt to accomplish the study of the wet welding process. The effects of preset welding parameters on the bubble evolution behaviors are investigated in detail. Four typical bubble evolution modes during the wet welding process and their corresponding welding electric information are determined to describe the bubble behaviors along with arc characteristics. Results indicated that the bubble evolution of underwater wet welding is unstable and complicated, necessitating control by adjusting the welding parameters to obtain a more stable protective effect. And there is a matching relationship between the coefficient of variation, weld appearance and bubble evolution mode for certain welding parameters. For underwater wet FCAW, a stable welding process can be acquired with a lower floating frequency and a larger maximum diameter of the bubble without arc extinguishing.