| 摘要 |
PURPOSE:To weld pipe materials made of Al alloys with excellent workability and welding quality in the stage of inserting said pipe materials to each other in their end parts and welding the same by incorporating specific ratios and shapes for the wall thicknesses of the inside and outside pipes and the shapes in the preceding end part of the outside pipe. CONSTITUTION:In the stage of welding pipes made of Al or Al alloys, the end part of an inside pipe 11 is inserted into the end part of an outside pipe 10, and both end parts are welded by a low frequency AC pulse welder. The relation T=(1.2-1.5)t is provided between the wall thickness T of the pipe 10 and the wall thickness (t) of the pipe 11. Such a slope 12 which has the diameter decreasing along the preceding end direction of the outside circumferential surface is formed to the preceding end part of the pipe 10 and is so formed that the wall thickness width (a) of the preceding end face is 0.5-1.0 times the thickness (t) of the pipe 1. Welding is accomplished by 1-8Hz low frequency AC pulse welding current. The joint part 13 of both pipes 10, 11 is formed of a good single pass weld zone 14, and the joint part of high quality is obtained with high workability. |
