| 摘要 |
PROBLEM TO BE SOLVED: To enhance soldering intensity at a connecting part by engaging a connecting head part involving an extended diameter part which has a cross-section arc-shaped wall or a cross-section rectangular wall in a dish-shaped seat part whose cross-section is step-wise, and soldering its contact and engagement part. SOLUTION: A main tube 1 is formed out of a thick-wall stainless steel tubing material, such as a pressure piping carbon steel pipe and a stainless steel pipe, at whose inside a flow passage 1-1 is formed. At the peripheral wall part over axial direction leading to the flow passage 1-1, the dish-shaped seat part 1-3 of a penetrated hole whose cross-section is step-wise is formed at a single point or a plurality of spaced points. A branch tube 2a is formed out of the same type of steel pipe or steel material as the main tube 1, as a branching connecting body. The connection head part 2a-1 is constituted of an extended diameter part 2a-2 and a straight cylindrical part 2a-3 whose end part has a wall 2a-2' of arc-shaped cross section. The extended diameter part 2a-2, of its head part is brought into contact with the dish-shaped seat part 1-3, and a mutual contact and engagement part is soldered 3. |
