| 摘要 |
PROBLEM TO BE SOLVED: To make the efficient production of taper tubes possible and to manufacture products having excellent quality in which weld defects are less than those in conventional products. SOLUTION: Butting parts are welded in the state where a metallic sheet 23b is set to an O-bending die 25b after performing the final bending of the metallic sheet with a manufacturing apparatus for taper tubes, the circumference of which is arbitrarily changeable in the axial direction for hydraulic bulging which is provided with a forming device by bending and a welding device. By this invention, the securement of high accuracy of a welded joint is enabled and the quality of a product is improved. Moreover, an off-line welding machine is not required, so exclusive equipment and personnel required for welding are unnecessary and a lead time is shortened, so that the efficient production is enabled. COPYRIGHT: (C)2004,JPO
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