Heating Characteristics of Gas Tungsten Arc Welding of Copper Thick Plates with Shielding Gas of Argon, Helium or Nitrogen

Abstract

The welding temperature patterns of gas tungsten arc welding for copper thick plates during Ar, He or N2 shielded arc welding were simulated, and the size of weld pools and heat-affected zones have been compared. It was predicted that the heat-affected zone in the welded joints during Ar arc welding is the widest and that during N2 arc welding is the narrowest, while the size of weld pools using Ar (preheating at 400°C), He and N2 (without preheating) shielding arc welding is very similar. Among the three kinds of gases shielded arc welding, the temperature gradient of welded joints during Ar arc welding is the least and that during N2 arc welding is the greatest. The temperature rise velocity at the arc center during N2 arc welding is the highest, and those at the zone close to the weld pool of welded joints during He arc and N2 arc welding are a few higher than that during Ar arc welding.