Abstract: A direct resistance heating method includes placing a first electrode and a second electrode on a plate-shaped workpiece such that the first electrode and the second electrode extend across the workpiece in a direction substantially perpendicular to a center line of a heating target region of the workpiece, the center line connecting a middle portion of one side of the heating target region and a middle portion of the other side of the heating target region; and moving at least one of the first electrode and the second electrode along the center line while applying electric current between the first electrode and the second electrode.

Abstract: An apparatus applies a wear coating on the interior surface of conduits, particularly conduit elbows, in which the weld head applying a weld bead forming the wear coating is supported by a wheel engaging the bottom surface of the conduit and interconnected with a push/pull cart mounted on a linear support frame exteriorly of the conduit by a plurality of linkage elements. Each of the head element and the linkage elements include a centralizing joint having a pair of transversely opposing rollers that engage the lateral sides of the conduit to maintain a consistent positioning of the welding arm at the distal end of the apparatus. The welding arm includes a three-axis adjustment for the welding torch tip for accurate location thereof within the conduit. Positional adjustment of the welding torch tip is provided by independent electric motors associated with each pivot axis in the welding arm.