| 摘要 |
PURPOSE:To eliminate trouble even at the time of reduction processing of cylindlical diameter at a large reduction ratio, by performing openings on a flange in a radial direction. CONSTITUTION:A flange 18 extending to a radial direction is formed at one end of an outer cylinder 14 in the axial direction of said cylinder and has a plurality of openings 20 formed toward the outer periphery thereof. At the time of reduction processing, each of the opening parts 20 of the flange 18 is closed or the sides of each opening mutually approach to enable the split flanges 18 to move to a mutually approaching direction. Therefore, the flange generates no rippling phenomenon even after draw processing and can retain a flat surface. |
