| 摘要 |
PURPOSE:To eliminate a residual stress generated in the inside circumferential part of a small diameter part after welding and to prevent the generation of stress corosion cracking, etc., by fitting the small diameter pipe into a large diameter pipe by limited depth and performing fillet welding. CONSTITUTION:A fitting part 4 is formed in the inside circumferential part of a large diameter pipe 1 and a small diameter pipe 2 is fitted therein. Fillet welding 3 is applied in the circumferential direction, whereby the welded joint of a dissimilar diameter concentrical circular pipe is produced. The insertion depth L of the pipe 2 in the part 4 is made smaller than the thickness t2 of the pipe 2 and larger than 0.2t2. Since the welded joint by this has no residual stresses present in its small diameter part and, therefore, there is no possibility of stress corrosion cracking when this is adapted to an austenitic stainless steel pipe used at high temp. and high pressure. The rate of working, the depth of insertion, etc. are required relatively less and therefore, the reduction in the number of working steps, and the saving of the usage of materials are made possible. |
