CO2-GMA hybrid welding of carbon steel – The effect of shielding gas composition

Abstract

Metal industry producing large structures is nowadays very interested in hybrid welding processes. That isn’t a surprise, as the process has many advantages compared to the conventional welding methods. One of the major benefits is the reduction in deformations. That reduces the post-work needed and makes the assembly easier since the hybrid welded parts are more accurate. Another advantage of hybrid welding is that it allows much wider groove tolerances compared to laser welding. In addition, with filler metal the composition can be balanced, if metallurgical factors are critical.In this study CO2-GMA hybrid welding process was used. The aim was to clarify the effects of shielding gas composition on welding performance, weld profile and quality in hybrid welding of carbon steel. Shielding gases used consisted of helium, argon and carbon dioxide. Joint types used were butt and T-butt joints.The research revealed that the composition of shielding gas affects welding performance, weld quality and penetration profile in CO2-GMA hybrid welding of carbon steel. Hybrid welds of a good quality can be produced with many different shielding gas compositions, but if the productivity, low gas costs, reliability of the process and high quality are desired, the shielding gas composition does make a difference in hybrid welding of carbon steel.Metal industry producing large structures is nowadays very interested in hybrid welding processes. That isn’t a surprise, as the process has many advantages compared to the conventional welding methods. One of the major benefits is the reduction in deformations. That reduces the post-work needed and makes the assembly easier since the hybrid welded parts are more accurate. Another advantage of hybrid welding is that it allows much wider groove tolerances compared to laser welding. In addition, with filler metal the composition can be balanced, if metallurgical factors are critical.In this study CO2-GMA hybrid welding process was used. The aim was to clarify the effects of shielding gas composition on welding performance, weld profile and quality in hybrid welding of carbon steel. Shielding gases used consisted of helium, argon and carbon dioxide. Joint types used were butt and T-butt joints.The research revealed that the composition of shielding gas affects welding performance, weld quality and penetratio...