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42 巻, 7 号
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研究論文
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千々岩 健児, 伊藤 光男, 加藤 正彦1970 年 42 巻 7 号 p. 523-534
発行日: 1970/07/25
公開日: 2012/10/01
ジャーナル フリーIt is difficult to measure the distribution of temperature or the development of solidified layer or the cooling rates of the real castings. Moreover, when there is a change in design or in positions or sizes of risers or chills. a new casting must be made every time to measure its temperature to know the changes in the distribution of temperature or the state of solidification. We have made an analog simulator by which the temperature and the change of temperature distribution of castings may be measured, which eliminates any need for making real castings. The simulator was designed as an electrical system from the requirement of a simple structure and easy measurement. It consists of number of unit blocks made up of condensers and resistances, the combination of which represents a casting. The heat of a casting is represented by the electric charge, which is discharged through the electric resistances corresponding to the heat resistance of casting, and the change of voltage is thus measured. The voltage corresponds to the temperature of casting. The influence of the latent heat of solidification is fed by another circuit, which is composed of a condenser and a resistance, connected to the main circuit. It acts when the voltage corresponds to solidification temperature. The simulator was made for aluminum castings and the change of temperature and the time necessary for the solidification of plates, square blocks and cross-shaped blocks of metal and sand mold castings were measured and their values were compared with the calculated values. They coincided very well and the experiment ended in success. This simulator is big, 125cm×185cm×30cm, but we are now trying to make a portable one. Simulators for cast iron and steel castings may be made in the same way simply by changing the resistances and the capacities of the condensers of the circuit.抄録全体を表示PDF形式でダウンロード (1013K) -
土井 基邦, 西 成基, 上田 俶完1970 年 42 巻 7 号 p. 535-544
発行日: 1970/07/25
公開日: 2012/10/01
ジャーナル フリーIn order to investigate the solidification process of cast iron, the solidification of high purity iron-carbon and iron-carbon-silicon alloys must be studied. A specially designed high frequency high vacuum melting furnace was developed to perform a series of experiments under a condition in which there will be a smallest possible influence from impurities and gases, and simplifying the factors influencing the solidification process and structure. To ensure nniformity of the samples in each series, about 500g of each raw alloy was prepared in a vacuum melting and casting furnace from pure graphite, pure silicon (with less than 0.1% of impurities) and electrolytic iron (with less than 0.1% of impurities). Approximately 50g of each alloy was remelted in an alumina crucible placed in the specially designed high vacuum furnace. The specimens were kept at various temperatures for a given period and then cooled at various speed. From the results of a few experiments with this apparatus, it is concluded that the experimental conditions such as temperatures, period and cooling rates can be strictly controlled. This apparatus was found to be satisfactory for experiments of the solidification of cast iron from observation of the solidification bahavior and the thermal analysis curves. In hyper-eutectic alloys, the primary graphite crystalization was observed directly on the surface of the samples.抄録全体を表示PDF形式でダウンロード (1155K) -
土井 基邦, 西 成基, 上田 俶完1970 年 42 巻 7 号 p. 544-555
発行日: 1970/07/25
公開日: 2012/10/01
ジャーナル フリーSolidification of high-purity Fe-C and Fe-C-Si alloys were studied by thermal analysis and metallographic techniques. The objective was to investigate the effects of holding temperature and holding time on the solidification of cast iron. The experiments were conducted in a specially designed high vacuum high frequency induction furnace under controlled conditions. The quantitative data obtained were analysed using the statistical method. The results obtained are summarized as follows : (1) As the holding temperature or the holding time increases, the graphite dimension becomes shorter, the distribution changes from type B to type D and the shape changes from flaky to spherulitic. (2) In hypo-eutectic Fe-C-Si alloys at high holding temperature (1,500°C), eutectic solidification starts with grey and then changes into white. In eutectic and hyper-eutectic alloys, no effects of holding temperature and holding time were observed on the thermal analysis curves. (3) The dimension of eutectic cell increases with the increase of the holding temperature. In other words, the number of eutectic cell is reduced by increasing the holding temperature. (4) There is little difference in the eutectic solidification times of samples even when the temperatures are varied. Therefore, it was found that the growth rate of a eutectic cell increases with the elevation of the holding temperature. (5) Consequently, the change of the holding temperature not only influences nucleation, but also the growth rate of the eutectic cell.抄録全体を表示PDF形式でダウンロード (1256K) -
千々岩 健児, 大北 一夫, 笹 徹, 大川 善邦1970 年 42 巻 7 号 p. 555-565
発行日: 1970/07/25
公開日: 2012/10/01
ジャーナル フリーA foundry shop of K works Co. produces 47 kinds of cast iron pipes by centrifugal casting. This foundry shop has 3 kinds of casting machines, small, medium and large ones, for each kind of cast iron pipes. They are used according to the diameter of the pipes. The pipes are completed when the bell ends are finished after casting in the finishing shop which has also 3 kinds of finishing machines, three machines for each kind of pipes the use of which depends on the diameter of the pipes. Under the present schedule of production various kinds of pipes are produced every day since the schedule is formulated by dividing the total amount of various types of pipes to be produced for a given month by the number of days in a month. This system is profitable since the tonnage of casting products produced each day is the same and the melting quantity of cupola does not fluctuate. Nevertheless, it does take a long time for preparation at the finishing stage because so many kinds of pipes are involved. In this study we tried to formulate a new schedule where in this preparation time was made as short as possible and tonnage of the casting products does not fluctuate very much. It was planned so that the pipes of identical diameters were cast and finished as continuously as possible, since it was considered that a preparation time was hardly necessary if pipes of identical diameters come to the machines continuously. The new schedule was found to shorten the time necessary for production from 25 days to 23 days, so that at present we are trying to put this system into operation. In scheduling, an electronic computor was used because of the complexity of calculation.抄録全体を表示PDF形式でダウンロード (822K)
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