| Project/Area Number |
62550504
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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 | Kyushu Institute of Technology |
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Principal Investigator |
KISHITAKE Katsuhiko Dept. Materials science, Professor, 工学部, 教授 (40029880)
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| Co-Investigator(Kenkyū-buntansha) |
NAGAI Kyoichi Dept. Materials science, Research Associate, 工学部, 助手 (50128120)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1988: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1987: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | undercooled graphite / coral graphite / ベイナイト鋳鉄 / 射出成形用金型 / 共晶状黒鉛鋳鉄 / 一方向凝固 |
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| Research Abstract |
The aim of this project is to develop bainitic coral graphite cast iron which is suitable for the plastics injection dies. In order to make clear the condition forming fine undercooled graphite, i.e. coral graphite, firstly the temperature of the solidification front of austenite-graphite eutectic was measured in Ti-bearing cast iron or vacuum-treated cast iron solidified unidirectionally. And the effect of oxygen and nitrogen on the graphite structure was investigated.
Secondary, coral graphite cast irons containing nickel and copper were austempered and the mechani-cal properties of the irons were examined. The results obtained are summarized as follows.
1) Increasing the growth rate changed the graphite morphology from flaky to fine undercooled type. The growth rate where the change took place decreased by the addition of titanium or vacuum treatment of melts.
2) The formation of the coral graphite did not necessarily need large undercooling.
3) The content of solute oxygen and solute nitrogen of the specimen with fine coral graphite structure was lower than those of the specimen with flaky graphite structure. Accordingly, it was concluded that the promotion of fine graphite structure by means of Ti addition or vacuum treatment was caused by the reduction of oxygen and nitrogen from the melt.
4) Bainitic structure were obtained by austempering treatement of the coral graphite cast iron contain-ing nickel and copper. The mechanical properties of this bainitic coral graphite cast iron was judged to be suitable for the plastics injection dies.
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