Welding Equipment and Process of Spiral Seam Welded Pipe in Tack-welding

The tack-welding characteristics,equipments and technologies in the two-stage SAWH pipe production are introduced. The welding equipments include two sets of DC1000A power source imported from the United States,an Ar+CO₂+O₂ tri-mixed gas proportioner,a laser tracking system developed by a British company and a large current MAG air-cooling torch developed by Harbin Welding Institute(HWI),with a ceramic composite nozzle which can be cleaned by itself through nozzle rotating. The experiments of pipe welding production are carried out with the equipments motioned above and combined with the high-speed and large current MAG welding technologies developed by HWI. After the tack-welding process,the weld shaping and microstructure of the samples are analyzed,and the impact properties of the welding line and the heat affected zone of the submerged-arc final welding samples are also analyzed. Through the experiments above,the expected results are obtained and the most important result is that the localization of the spiral pipe tack-welding equipments is realized.