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47 巻, 9 号
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研究論文
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大出 卓, 大平 五郎1975 年 47 巻 9 号 p. 615-620
発行日: 1975/09/25
公開日: 2012/09/18
ジャーナル フリーThe alloys were prepared from electrolytic iron, electrode graphite and iron-phosphorous alloy. This study was conducted by classifying three primary crystallites : austenite, iron phosphide and iron carbide. A characteristic solidification type was suggested by the peculiar segregation effect of phosphorous. The unidirectional solidification structures obtained were particularly interesting. Primary austenite did not grow dendritically at slow rate. Primary iron phosphide showed a special square type pattern and primary iron carbide (cementite) was plate-like with many small quasi-hexagonal units conbined.抄録全体を表示PDF形式でダウンロード (998K) -
鵜飼 直道, 上野 晴信, 村松 寧1975 年 47 巻 9 号 p. 621-625
発行日: 1975/09/25
公開日: 2012/09/18
ジャーナル フリーThe melting was carried out using butane-fired crucible furnace and melting atmosphere was controlled at CO2%/(CO2%+CO%) (C value) of combution gas which contacted with molten metal. C values in this work were 1.0, 0.95, 0.8 and 0.5. Tensile strength, specific gravity and fracture characteristics of specimens cast in various molds were investigated.
When deoxidizing and/or degassing agents are not added, the highest strength was obtained in castings melted at C value of 0.95. There is a suitable agent and amount corresponding to the melting atmosphere. It is effective to estimate melt quality by fracture characteristics as a foundry test. It is difficult, however, to infer the strength of castings from the fracture characteristic in this study. Considering the specific gravity as a property, properties of castings in shell mold is most sensitive and the specific gravity of castings is in direct correlation with tensile strength.抄録全体を表示PDF形式でダウンロード (664K) -
林 清讃, 中田 毅, 林 徹男1975 年 47 巻 9 号 p. 626-632
発行日: 1975/09/25
公開日: 2012/09/18
ジャーナル フリーThis paper attempts to study how additional elements influence the dendrite morphology of Zn-22%Al alloys having long freezing range. 1% of Cu, Cr, Mg, Mn, Ni, Si, Ti, V and Zr elements were added individually. The cooling rate and other casting conditions were kept constant.
Primary dendrite arm length of alloys increase rapidly until the drop temperature is approximately 30°C from liquidus by adding Cu, Ni, Si, Ti, V and Zr elements, and 20°C by adding Cr, Mg and Mn elements. Secondary dendrite arm length of alloys also increase rapidly until the drop temperature is approximately 40°C, and secondary arm cell size and arm spacing increase gradually with the increase of drop temperature by adding every one of the above elements. Regression lines were obtained between the shape factors of dendrite and solidification times. The gradients and absolute values of regression lines for primary dendrite arm length were different with each additional element, but for other shape factors they were almost the same. The dendrite morphology of alloys changed by the additional elements may be classified into (a) petal-like, Ti, (b) equiaxed, Mn and Ni, and (c) nodular, Zr. The linear growth of dendrite is encouraged by adding Cr, Si and V, and the secondary arm is coarsened by adding Mn, Ni, Ti, and Zr. Mn, Ni, Ti and Zr are effective elements for refining the dendrite structure of Zn-Al alloys.抄録全体を表示PDF形式でダウンロード (1174K) -
岡倉 常之1975 年 47 巻 9 号 p. 633-638
発行日: 1975/09/25
公開日: 2012/09/18
ジャーナル フリーTwelve kinds of domestic and foreign bentonite were kept for a day in a desiccator with saturated salt water at the bottom. Each peak of endothermic curves obtained by differential thermal analysis was classified into either A type (below 200°C), B type (about at 600°C) or C type (about at 700°C). From the results of measurements of the area of these peaks, it was found that there was a linear relation between the total sum of these three type of area of peaks and the maximum green tensile strength. In general, the total sum of the area of these peaks of Ca-type bentonite was larger than that of the Na-type bentonite and that of the alkali-treated Ca-type bentonite was smaller than the original Ca-type bentonite.抄録全体を表示PDF形式でダウンロード (661K) -
山田 俊宏1975 年 47 巻 9 号 p. 639-644
発行日: 1975/09/25
公開日: 2012/09/18
ジャーナル フリーGraphite shape was changed by controlling the amount of Fe-Si-Mg (20%) addition and matrix of the specimens was controlled to ferrite in order to interfere with the production of the thick oxide film on the sliding surface at high sliding speeds. The wear tests were carried out by a pin-and-disk type machine under a dry condition. So as to obtain good reproducibility, the wear resistance was judged both at the maximum and the minimum points of the wear characteristics curves, at which points wear is considered to take place by the same mechanism.
At above 80% graphite spheroidization, where worm-like graphites were not present, a distinct change in wear resistance was not recognized, but below 70%, where many worm-like graphites were present, wear increased, in proportion to the mass of worm-like graphites. It was found that graphite shape is one of the most important factors which govern wear of spheroidal graphite cast iron, and that the degree of graphite spheroidization of above 80% is required to ensure an improved wear resistance of the cast iron.抄録全体を表示PDF形式でダウンロード (766K) -
木村 蓊, 宮佐 明, 小沢 良平1975 年 47 巻 9 号 p. 645-650
発行日: 1975/09/25
公開日: 2012/09/18
ジャーナル フリーLocal metal penetration formed on malleable cast iron pipe fittings is a difficult phenomenon to understand because it appears on the top of pipe fittings where although foundry sand is packed most densely the metal enters deeply into the fine inter-granular cavities in the sand mold. In order to study the mechanism of the local penetration the mold-metal interface was observed under the metallographic microscope and the X-ray microanalyser, and the penetration was investigated.
Iron oxide containing SiO2 and MnO is found at the mold-metal interface of the penetration and there is some trace of the dust of mold sand fusing during pouring near the mold-metal interface. Sand mold mixed with a large amount of new sand is effective in reducing the penetration. The penetration can not be prevented by using zircon sand and chromite sand, although these sands are effective for the penetration of steel castings. The dust of mold sand which increases by repeated use fuses easily compared to bentonite and ash of seacoal. It fuses at temperatures below 1,100°C.抄録全体を表示PDF形式でダウンロード (897K) -
久保田 博, 木村 徹, 津金 秀司1975 年 47 巻 9 号 p. 651-657
発行日: 1975/09/25
公開日: 2012/09/18
ジャーナル フリーIn pressurized casting process, the molten iron was poured either in silicate bonded molds or green sand molds placed in a pressure chamber. After pouring, the chamber was immediately closed, and nitrogen gas was subsequently introduced to the chmaber. The molten iron was solidified under a fixed nitrogen gas pressue in the range of 1 to 10kg/cm2.
Pressurized casting was found to reduce the shrinkage cavity of spheroidal graphite cast iron castings in silicate bonded molds, and also that more than 5kg/cm2 was necessary to produce sound castings. On the other hand, the effect of pressurized casting was not uniform in castings by green sand molds.抄録全体を表示PDF形式でダウンロード (750K)
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