A CO_2 Gas Shielded Gas Tungsten Arc and Its Application to Welding of Steel Sheets

摘要

In order to develop a novel welding process with low costs and high productivity in comparison with the TIG welding process, the characteristics of aCO_2 gas shielded gas tungsten arc (GTA) are studied. A double gas shielded system which consists of CO_2 gas and inert gas is employed for the GTA welding torch due to avoiding the consumption of tungsten electrode. The arc voltage of the CO_2 gas shielded GTA in the conditions of arc current 150 A and arc gap 3 mm is about 19 V which is much higher than 12 V of TIG arc in the same conditions. The CO_2 gas clearly constricts the arc and the maximum heat intensity at the surface of a water cooled copper anode in the CO_2 gas shielded GTA becomes about 10 times larger than that of TIG arc. Furthermore, the CO_2 gas shielded GTA has very good performance in the traveling speed for welding zinc coated steel sheets in comparison with the TIG welding process.