Arc Welder and Related System

[0048]A welding system was setup with a CV power supply, a GMAW gun, a water-cooled GTAW torch, and four 0.1 ohm power resistors controlled by four IGBTs. The tungsten electrode, protected by a water cooling system, had a diameter of 3.2 mm. Pure argon was used to shield the GMAW gun and GTAW torch. The gas flow rates for the GMAW gun and GTAW torch were 16.5 L / min and 7.1 L / min, respectively. The following parameters were used to determine the geometrical relationship between the GMAW gun, GTAW torch, and base metal: the distance from the GMAW contact tube to the base metal was set to 20 mm; the distance from the bypass electrode to the base metal was set to 5 mm; the distance between the bypass electrode and the electrode wire was set to 4mm; and the angle between the electrode wire and the tungsten electrode was set to 60°. The base metal was a mild steel plate measuring 50×120×2 mm. A low-carbon welding wire (ER70S-6) with a diameter of 1.2 mm was used. The welding voltage was