With the development of high-voltage switchgear industry, the SF6 metal-enclosed switchgear, known as Gas Insulated Switchgear, GIS plays a significant role in transporting and transformation project. Circuit breakers, busbars and their shell mainly use aluminum magnesium alloy. Aluminum shell is one of the main components of the GIS product suit. Power busbar switch: Material : 5052 AI-Mg alloy and aluminum alloy Wall Thickness: less than 16mm Diameter: less than 1000mm Structure type : cylinder longitudinal seam, butt joint circumferential seam, pipe-flange inside and outside comer welding Welding seam requirement: pass X-ray inspection Welding method: aluminum alloy is a good heat conductor, so it is better to use centralized pulse MAG welding . One point is to improve working conditions to get better welding seam; and another point is to improve working efficiency. In order to improve welding seam shaping, we use AC TIG welding to modify the cover. Welding process: it is possible to use expert parameters to get optimal welding results, and to get stable one pulse one drop welding, which is also good for even shaping and perfect welding quality. In order to improve welding shaping, dual-pulse MIG welding technique is applied, to get similar welding quality as that of TIG welding. Welding gas: Argon or Argon with helium （30% or 50%） Filling wire: ER5356, diameter 1.2mm or 1.6mm The longitudinal seam is not only finished on longitudinal seam welding system, but also applied in automatic welding system, which is made up of column&boom, inclined roller, and positioner and used for longitudinal seam welding, circumferential seam welding and comer weld as well.