Research on Droplet Size of Short-Circuiting Transfer in CO2 Gas-Shielded Arc Welding Based on High-Speed Photography

In order to observe the metal transfer behavior in CO(2 )gas-shielded arc welding, an optical imaging system was established and video images of droplet were captured by a high-speed camera. Based on these images, the droplet size at the moment of short-circuit was accurately measured by ellipsoid-sphere conversion method, and the effects of welding parameters including welding current, welding voltage, wire extension and welding speed on droplet size were also analyzed. The results show that, the droplet size is inversely proportional to welding current and proportional to welding voltage. With the increase in the length of wire extension, the droplet size decreases first and increases later, within the allowable welding range, welding speed hardly affects the droplet size. Lastly, considering both welding efficiency and welding quality, the optimal welding parameters are determined.