The cooling pipe is characterized in there is the formation of direct chemical bonds between the copper elbow welded face and the wall surface of aluminum U tubes.

The welding method core of cooling pipe is two-point welding technique between copper elbow and aluminum U tube. And the cooling pipe is characterized by that two groups same phase and insulated moving electrodes are connected to both ends of the copper elbow, aluminum U tube connected to the fixed electrode; there is the opening hole on the welding position of fixed electrode plate, installing the mosaic of blocks; the cylinder push the electrodes with copper elbow move to the tube, while resistance heating on the combined area of copper and aluminum; copper elbow will be moved to the tube inside under the action of cylinder pushing.