1990 Fiscal Year Final Research Report Summary
Development and Practical Use of Toughened Austempered Ductile Iron
| Project/Area Number |
63850147
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B).
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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 | Toyohashi University of Technology |
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Principal Investigator |
KOBAYASHI Toshiro Toyohashi University of Technology ・ Engineering ・ Professor, 工学部, 教授 (90023324)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEUCHI Kuniaki Nissei Industries, Ltd. ・ Department of Research and Development, Section Chief, 研究開発部, 課長
MATSUO Kunihiko Kurimoto, Ltd. ・ Material and Technology Center ・ Head of The Metallic Materials, 金属材料技術部, 部長
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| Project Period (FY) |
1988 – 1990
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| Keywords | Austempered ductile cast Iron / toughening / gear wheel / fatigue property |
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| Research Abstract |
This research is consisting of three steps as follows.
(1) Development and evaluation of a new austempered ductile cast iron
from the results of various tests such as tensile test, instrumented Charpy impact test and fracture toughness test, it has been clarified that the newly developed toughened austempered ductile cast iron (TADI) has greater strength and toughness than the conventional austempered ductile cast iron (ADI). Moreover, it has been clarified that the loss of ductility in the ADI is due to the formation of chi-carbides and the precipitation of the secondary graphites.
(2) Evaluation of fatigue properties, durabilty and noise of TADI
at first, the fatigue propagation test has been conducted. It has been confirmed that both of the fatigue crack initiation resistance and fatigue crack propagation one are higher than the conventional ADI. Its cause can be considered due to the increasing of the crack nucleation energy by the TRIP effect in the retained austenite phase. Next, the durability test and the noise one have been conducted for the gear wheel made from the TADI. It has been confirmed that TADI can prolong the life time and lower the noise of the gear wheel.
(3) Trial test of the TADI gear wheel
The TADI gear wheel has been put into the reduction gear combined motor and the durability test has been conducted. It has been found that the TADI gear wheel has almost the same durability with the one made from SCM material. We can have the confidence from these results that the TADI can be used practically as the gear wheel material.
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