Abstract: A welding apparatus which is designed to weld together tubular members having any exterior configuration. The welding electrode is mounted on mounting structure which in turn is movably mounted upon the periphery of a housing. The workpiece to be welded is fixedly secured and centrally disposed within the housing. The welding head is to move about the workpiece and also tilt in respect thereto to maintain the longitudinal center axis of the welding electrode continuously perpendicular to the workpiece surface. Step motors are employed to both drive the welding head about the workpiece and also tilt the welding head with respect to the workpiece. The particular exterior configuration of the workpiece has been preprogramed into a memory unit. The memory unit operates through an electronic circuit to operate the step motors to locate the welding head at the precise desired location along the entire length of the welding path.