| 摘要 |
PURPOSE:To enable to use materials other than aluminum and produce the tube which is large in length and diameter and has a reduced wall thickness by a method wherein fins are formed by shaving on an extruded long plate-shaped blank material provided with fin-erecting protuberant parts on both sides thereof, the thus finned blan material is bent into the shape of a tube and the lateral edges of the material are jointed with each other. CONSTITUTION:The skive-fins 4, 5 are formed by shaving at the fin-erecting protuberant parts 2, 3 which are provided on both sides of the long flat plate blank material 1 and extending in parallel with the longitudinal direction A of the material 1. The thus finned blank material 10 is bent in the width direction thereof, with the back face being on the inside, and the lateral edges are abutted and jointed with each other to obtain a tube body 6. Accordingly, materials other than aluminum can be used, the fins are increased in height, and the tube with an increased diameter and a reduced wall thickness can be produced. |
