| 摘要 |
PURPOSE:To easily manufacture the finned pipe having a fin in the axial direction of the pipe outer periphery by drawing the hollow tube stock with a circular sectional outer periphery and a thick fin forming part by a specific die. CONSTITUTION:The hollow tube stock having a thick part B at the part corresponding to the fin D, D of a finned pipe as a product on the inner face of a cylindrical metal pipe A whose inner diameter is iD and outer diameter oD, is subjected to a cold drawing by using the die having an inlet port part (a), lead-in port (b) forming part (c) and holding part (d). In this case, a fin part is mainly formed at the drawing initial term as shown in the tube stock (e) prior to drawing and (a), (b), (c), and then by mainly forming the tube part at the drawing end term as shown in (d) the fin part difficult to work is formed within less work hardening at the drawing initial term and the finned tube C having a fin part D is simply manufactured without using a special roll.
|
