著者

坂本 満 秋山 茂 萩尾 剛 大城 桂作

出版者

Japan Foundry Engineering Society

雑誌

鋳造工学 (ISSN:13420429)

巻号頁・発行日

vol.69, no.3, pp.227-233, 1997-03-25 (Released:2011-02-01)

参考文献数

10

被引用文献数

13

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The oxide films formed on the molten Mg-Ca alloy were investigated by using an optical microscope, scanning electron microscope (SEM), X-ray diffraction and X-ray photoelectron spectroscopy (XPS) in order to elucidate the effect of Ca addition on the suppression of ignition and burning of the molten metal. While the pure Mg almost always ignited and burnt before melting down, the Ca addition increased the ignition temperature by about 250K, at which a very thin and uniform oxide film was formed on the molten Mg-5mass%Ca alloy, X-ray diffraction and XPS revealed that the oxide film on the Mg-5mass%Ca alloy consisted of two layers ; most upper layer of CaO and mixed layer of MgO-CaO under the CaO layer. The former was very thin and its thickness was independent of the exposure time at 973K in air, but the latter gradually grew with the exposure time. It appeared that the CaO film first formed depressed the volatilization of Mg and the permeation of oxygen gas, which made the molten alloy incombustible and manipulatable in air.

著者

髙橋 芳朗 清水 一道 足立 真彦 大城 桂作 片岸 庄史

出版者

Japan Foundry Engineering Society

雑誌

鋳造工学 (ISSN:13420429)

巻号頁・発行日

vol.75, no.3, pp.196-201, 2003-03-25 (Released:2011-02-01)

参考文献数

21

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Solidification structures and frictional wear characteristics of high P cast iron containing 3.3 mass%C, 1.7 mass%Si, 1.4 mass%Mn, 0.3-3.0 mass%P, 0.37 mass%Cr, 0.20 mass%V were examined with an image analyzer and original braking test machine. High P cast iron consists of steadite, eutectic cementite and flaky graphite distributed in pearlitic matrix. The addition of higher levels of P increases the steadite, which raises frictional wear resistance against the wheel steel.The wear resistance effectively improved with the addition of about 0.6 mass%P. The braking ability also improved with the addition of more than 1 mass%P at the initial braking speed of above 15 m/s. The contact surface was heated above 990 K at the initial braking speed of 25 m/s and the steadite partially melted or softened, which enhanced the braking ability of cast iron.

著者

池田 朋弘 梅谷 拓郎 甲斐 信博 大城 桂作 赤木 大地 野田 尚昭 佐野 義一

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.851, pp.16-00455-16-00455, 2017 (Released:2017-07-25)

参考文献数

26

被引用文献数

2

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In this study, the notch strength σBnotch was investigated for high silicon solid solution strengthened ferritic ductile cast iron in comparison with the tensile strength σBsmooth. High speed tensile tests were conducted on notched and smooth specimens at various strain rate and temperatures. The strain rate-temperature parameter (R parameter) is found to be useful for evaluating the temperature and strain rate upon the notch strength. The required range of R parameter was investigated for welded structural members in several industrial fields. The notch strength σBnotch is always larger than the tensile strength at room temperature σB,smoothRT in the range of R parameter required for the welded structures. Therefore, tensile strength σB,smoothRT is confirmed to be more useful than Charpy absorbed energy for the structural design. It is expected that the high Si ductile cast iron has wide industrial application potentiality.