| 摘要 |
PURPOSE:To prevent the occurrence of defects of a welded zone by cutting the pipe plate surface in the specific dimensional range in a circumferential shape and notching the contact surface between the pipe and the pipe plate at the time of cutting the welding surface of the pipe plate. CONSTITUTION:The pipe 2 is inserted into a pipe hole of the pipe plate 1 and expanded and brought into close contact with the pipe hole in advance. Next, a cut part 9 in the circumferential shape is formed on the outside periphery of the pipe 2 and further, a notched part 10 is formed on the contact surface between the pipe 2 and the pipe plate 1 so that the weld zone is welded to the pipe plate 1 in a lip welding state. At this time, depth and width of the cut part 9 are restricted to >=0.2mm and in the range of 1-5mm respectively. The depth of the notched part 10 is also made in the range >=0.2mm. Next, the TIG welding is performed with a torch 4 to form weld metal 8. Since the occurrence of blowholes and oxidation by oxygen and hydrogen can be prevented, the occurrence of the defects of the welded zone can be prevented.
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