| 摘要 |
PURPOSE:To prevent stress corrosion cracking and fatigue cracking from occurring at a weld zone by providing a longitudinal hole and a lateral air hole which communicates with it in a metallic piece when connecting an austenite stainless steel pipe by the overall-cirumference fillet welding of a metallic piece. CONSTITUTION:Austenite stainless steel pipes 1a and 1b are connected together by the overall-circumference welding of a metallic piece 3. In this used metallic piece 3, a longitudinal hole 5 communicating with end surfaces 4a and 4b which abut on the steel pipes 1a and 1b are made, and a lateral hole 6 from a side surface of the metallic piece 3 to the longitudinal hole 5 is bored as an air hole. Spaces 8a and 8b between steel pipe surfaces surrounded with deposited metal 7 communicate with the air through those longitudinal hole 5 and lateral hole 6. Therefore, even if the temperature in the spaces 8a and 8b rise extremely owing to the high-temperature use of the steel pipes, residual water is not held under high pressure and discharged gradually to dry the spaces, thereby causing neither stress corrosion cracking nor fatigue cracking due to high temperaure and high- pressure moisture. |
