Abstract: Pre-stressed insulated concrete panels are disclosed. Methods of making and using pre-stressed insulated concrete panels are also disclosed.

Abstract: A method is disclosed for applying a weld overlay to a tube. Using a first weld head, a bead of overlay material is applied onto a tube by melting the overlay material. In the process of applying the weld bead to the tube, a heat affected zone is created within the tube. Thereafter, a second weld head is employed to apply sufficient heat to the exterior of the tube to raise the temperature within the heat-affected zone to a temperature higher than its tempering temperature but lower than its Ae1 temperature. In this manner the heat affected zone is eliminated without creating a new heat affected zone in the process.In the disclosed embodiment, the tube is rotated with respect to the weld heads, while the weld heads move along the longitudinal axis of the tube. According to the disclosed embodiment, the first weld head employs a gas-metal arc welding process, and the second weld head employs a gas-tungsten arc welding process.

Abstract: An apparatus for circumferentially and longitudinally positioning a weld head or other tool with respect to the surface of a pipe. A first annular ring is affixed to the pipe. A longitudinally movable annular indexing track is also circumferentially fitted about the pipe and rides upon a plurality of support rods mounted to the indexing track. The support rods are slidably received within corresponding holes in the clamping ring and extend longitudinally and parallel to the outer surface of the pipe. A motor mounted to the fixed ring drives a ring gear concentric to the fixed ring to reciprocate a ball screw which moves the second longitudinally moveable ring toward and away from the fixed ring. An orbitally moveable third annular ring is circumferentially mounted to the second ring, and a second motor mounted to the fixed ring drives a telescoping drive shaft which rotates the orbital third ring.