| 摘要 |
<p>In a method of manufacturing a radial cross section pipe, in order to easily form a fold portion along a desired range in a direction of a pipe axis so that a level difference between a crest portion and a root portion is great, the same number of first pressing sheets (8) and second pressing sheets (9) are alternately arranged by positioning a pipe material (1) along a fold portion forming area in an axial direction at an outer periphery of the pipe material (1). A radial fold portion (12) is formed by deeply pressing the first pressing sheets (8) in a centripetal direction and shallowly pressing the second pressing sheets (9) in the centripetal direction. <IMAGE></p> |
