| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a hollow-formed product by which a large working quantity can be obtained and a product having high accuracy can be formed. SOLUTION: A primary formed material C having a solid in the intermediate part C1 and opening parts C2, C2 are formed by forging a solid blank A, spinning work is performed while leaving the intermediate part C1 of the primary material C as the solid-state and at the same time, the solid position of the intermediate part C1 is plastically worked from both sides of the inner part and the outer part, and a secondary formed material D, in which the intermediate part D1 is solid and both end parts D2, D2 show cylindrical state having smaller diameter than the outer diameter of the intermediate part D1 through tapered parts D4, D4 are formed. Both end parts D2, D2 of the secondary formed material D are compressed toward the intermediate part D1 side and at the same time, the solid portion in the intermediate part D1 is plastically worked from the inner and the outer both sides and largely bulged to the outer part while leaving the solid part in the intermediate part E1 and a ternary formed material E showing both end parts E2, E2 as a small diameter cylindrical state, is formed. The solid portion in the intermediate part E in the ternary formed material E is punched out so as to form a finished hollow-formed product F in which the intermediate part F1 communicates with both end parts F2, F2. COPYRIGHT: (C)2008,JPO&INPIT
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