Butt Welding Experiment on Aluminum Pipe using a Space Gas Hollow Tungsten Arc Welding Process with a Filler Wire Feed in a Simulated Space Environment

Abstract

Gas hollow tungsten arc (GHTA) welding experiments on aluminum pipe were performed in a simulated space environment and in a vacuum at 1 G. Square butt welding joints with a non-root gap on aluminum pipes were formed by orbital welding with filler metal using a pulsed DC power supply in a vacuum chamber under 10⁻² G and 1 G gravity conditions. The butt welding process during aluminum-pulsed DC GHTA welding with a filler metal was investigated by analyzing images obtained using a high-speed video camera. In addition, the macrostructure and mechanical properties of the butt welding joints were investigated. The results revealed that arc discharge and melting–solidification during pulsed DC GHTA welding were insensitive to the gravity conditions because welding is strongly affected by the impulsive arc pressure generated by the peak current. In addition, GHTA welding experiments performed in a simulated space environment demonstrated that pulsed DC GHTA welding with a filler metal can produce defect-free aluminum butt welding joints with sufficiently high strength.