Application of Inside Three Wire Welding on Tack-welding Process for SAWH Pipe

The inside three wire welding process of finishing welding is studied based on the tack-welding process for SAWH pipe. The inside welding mechanical equipment and control system of the fin ishing welding unit are described. The five wire welding for inside and outside finishing welding is realized with the optimization of the welding power supply parameters and configuration and position parameters of the inside three wire welding process.The statistics of the practical production data of the steel pipe with size of Φ1 016 mm×15.3 mm and grade of X80M shows that the appearance quality, inner quality and mechanical properties of the welding seam of SAWH pipe with the inside three wire welding process are all superior to those of the welding seam with the inside two wire welding process.