| 摘要 |
PURPOSE:To obtain a hollow vacuum vessel comprising various sectional shapes suited to vacuum to ultrahigh degree, by bulging a material tube to protuberantly form a boat. CONSTITUTION:Inner pressure P and an axial load F are synchronizedly applied to a material tube 1', to form said material tube 1' into a shape corresponding to a metal die 5 provided outside the material tube 1'. Hence, a predetermined boat 2 is formed. Hereon, a flange 4 is attached to said boat 2 by burring. Hence, the vacuum vessel comprising the main body 1 of the vessel, the boat 2 and the flange 4 having the improved reliability of strength is obtained. |
