| Summary: | 碩士 === 國立虎尾科技大學 === 機械與機電工程研究所 === 97 === Stamping process is usually applied in sinking the open end of high pressure vessels. The amount of sinking has to be divided to several stamping operations to avoid buckling on the vessel body. Therefore, the adjustment of the stamping dies becomes complex, die parts are increased, and die cost becomes expensive. Moreover, process annealing is required to avoid fracture on the workpiece from excessive strain hardening in the transfer-stamping. Rotary swaging is a genre of incremental deformation. Strain hardening is minimal and its die design methodology is simple. It requires only one stage of rotary swaging to achieve the same geometry by transfer-stamping. This work applies experiments and FE software DEFORM-2D to investigate the effects of feeding speed on the distribution of thickness, hardness and strain for the rotary swaging process. The comparison is made with the transfer-stamping to evaluate the feasibility of sinking high pressure vessels with rotary swaging process.
The forming tests showed that thickness was similar from the stamping and rotary swaging processes. The influence of feeding rate on thickness was insignificant. Hardness tests indicated the hardness on the inner tube was greater than that of outer tube. Moreover, hardness level of rotary swaging was less than that of stamping. The influence of feeding rate on hardness was insignificant as well. Tube sinking with rotary swaging with preforms without annealing had better distributed hardness. The simulations also showed the effective strain on the inner tube was greater than that of outer tube. Axial stress was smaller in sinking with rotary swaging.
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