| 摘要 |
PURPOSE: To press-fit and to stabilize the notch on a metallic pipe by shrinkage of a weld spot at the time of cooling by dividing a metallic fin into two halves, providing the halves with a semi-circular notch that fits the outer diameter of the metallic pipe, and welding a gap at the parting line after mounting the halves on the pipe. CONSTITUTION: Each metallic fin is divided into two halves 2, 3, each of which is provided with a semi-circular notch 4, 5 having a radius r that fits the outer diameter D of a metallic pipe 1, and each of which is produced to have a side face 7, 8, 9, 10 on both sides of the notch parallelly against a parting line 6. Then, a distance of the side face 7, 8, 9, 10 from the parting line 6 is set so that a gap S is obtained between the opposing side faces after both halves 2, 3 or the fin are mounted on the metallic pipe 1. Then, after both halves 2, 3 of the fin are mounted on the metallic pipe 1, the gap S between the halves 2, 3 is welded; the weld spot 11, 12, when cooled, shrinks and reduces the gap so that both halves of the fin are press-fitted on the metallic pipe 1 at the notch 4, 5. Consequently, both halves 2, 3 of the fin are spot-welded to each other and fixed on the outer surface of the metallic pipe 1 by force transmission coupling. |
