The invention relates to the field of automated welding, and more particularly, to an automated, gas metal arc welding apparatus for externally welding abutting sections of pipe. The apparatus has a motorized main carriage for travelling circumferentially about one of the pipe sections to be welded. The apparatus is provided with a welding torch which is connected to the main carriage. The welding torch is movable relative to the main carriage by the actuation of a multi-axis drive mechanism. The multi-axis drive mechanism has a horizontal transport mechanism for linearly translating the torch transversely of the weld seam, a vertical transport mechanism for vertically displacing the torch transversely of the weld seam and an angular transport mechanism for pivotally moving the torch transversely of the weld seam. A controller is provided for actuating the various transport mechanisms individually or simultaneously if desired.