| 摘要 |
PURPOSE: To improve the durability against fatigue or creep by interposing a tube of an austenite steel having a predetermined length between a steel tube and a header in a welding structure in which the tube of a ferrite steel is stood on the surface of the header of the ferrite steel and connected. CONSTITUTION: When a ferrite steel tube 2 is connected to a ferrite steel header 1, austenite steel tube 3 is interposed between both the tubes 1 and 2. The tube 3 is set to the length which can be extended to the position separated by 1/2 or more of the outer diameter of the tube from the welding stop end 13 of the tube 3 to the header 1. A route 6 of an annular protrusion partly cut at the tube welding position at the periphery of the position of the header 1 side of the connector of the tube 3 to the header 1, while the end of the tube 3 is formed with a route 6' collided with the route 6. Then, the routes 6 and 6' are butted to form a V-shaped groove 5, and which is welded by using an Ni-based alloy welding material. |
