Browsing by Author "Hung, JC"

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The design and development of a hydrostatic extrusion apparatus
(2000-08-31)
Hung, JC
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Hung, CH
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機械工程學系
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Department of Mechanical Engineering
The purpose of this research is to design and construct an experimental hydrostatic extrusion apparatus which has a maximum working pressure of 10 000 kg/cm(2). and to reduce the cost of this extrusion apparatus. The high-pressure extrusion container has been designed with two-layer pyramidal cylinders, and the material used was SKD61 which is cheap and readily available. Different materials and designs for high-pressure seals were tested and analyzed for the best combination performance. Problems in the extrusion processes using this device a ere analyzed and solved, which increased the reliability of the device. The results of extrusion experiments have established that this device is practicable, (C) 2000 Published by Elsevier Science S.A.
The influence of ultrasonic-vibration on hot upsetting of aluminum alloy
(2005-08-01)
Hung, JC
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Hung, CH
;
機械工程學系
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Department of Mechanical Engineering
The traditional ultrasonic apparatus cannot be operated at high temperature, explaining why the effect of ultrasonic-vibration on high temperature metal forming has seldom been addressed in literature. This study establishes an ultrasonic-vibration hot upsetting system. A cooling mechanism is used to solve the problem of high temperature. The effects of temperature and strain rate during ultrasonic-vibration on the upsetting of aluminum alloy were explored using this new system. Experimental results indicate that ultrasonic-vibration can considerably reduces the compressive forces during hot upsetting. The reducing effect on compressive forces decreases while the temperature increases. The strain rate does not significantly affect the reducing effect on compressive forces. (c) 2005 Elsevier B.V. All rights reserved.