| Project/Area Number |
60550489
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属加工(含鋳造)
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| Research Institution | Kyoto Institute of Technology |
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Principal Investigator |
FUKUDA Masayoshi Professor, Kyoto Institute of Technology, 工芸学部, 教授 (20027741)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAKURA Norio Research Associate, Kyoto Institute of Technology, 工芸学部, 助手 (40163183)
MORI Ken-ichiro Research Associate, Kyoto Institute of Technology, 工芸学部, 助手 (80127167)
YAMAGUCHI Katsuhiko Assosiate Professor, Kyoto Institute of Technology, 工芸学部, 助教授 (90027805)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1986: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1985: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Superplastic Forging / Rigid-plastic Finite Element Method / Optimum Forging Speed / Deformation Resistance / ひずみ速度感受性指数 |
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| Research Abstract |
In recent years, Ni- and/or Ti-based superalloys are widely used as new materials for various parts such as turbine blade and disk which must be proof against high temperature and pressure. However, since these materials have high deformation resistance and low ductility, it is very difficult to produce such parts by a conventional cold forging process. Thus, for the production of precise superalloy parts with complicated shape, the so-called superplastic forging is employed. In this forging process, the forging is carried out under a high temperature and the forging speed is kept very slow to prevent the occurrence of cracks. The slow forging speed is due to the rate sensitivity of the material and this leads to another problem of low productivity.
To overcome this problem, in the present investigation, the rigid-plastic finite element simulation of the superplastic forging is made and the stress, strain, strain rate and temperature distributions of the material during the forging are
… More
calculated. For this simulation, the accurate data of the deformation resistance of material and of the frictional coefficient for various strain rates and temperatures are inevitable as fundamental data. From this point of view, the deformation resistance and the coefficient of friction are also measured using a computer controlled high speed press which enables compression tests under the constant strain rate.
The results of the FEM simulation for a simple model of the superplastic forging are qualitatively consistent with the experimental observation. A new empirical expression of the deformation resistance is derived from the compression test of 18-8 stainless steel. This expression is able to estimate not only the effects of strain, strain rate and initial temperature of the material but also the effect of the temperature rise due to plastic deformation. This made it possible to predict the experimental results that for the high speed compression the deformation resistance decreases with increasing plastic strain.
On the basis of the results obtained from this investigation, a further study should be extended to the practical superplastic forging of various materials. Less
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