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56 巻, 9 号
選択された号の論文の7件中1～7を表示しています
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研究論文
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米倉 浩司, 岩堀 弘昭, 山本 善章, 沢 至郎, 佐々木 正博1984 年 56 巻 9 号 p. 521-526
発行日: 1984/09/25
公開日: 2011/11/26
ジャーナル フリーShort run defects are often formed far from the sprue in small steel castings cast in a multiple cavity mold. From the study of the metal flow behavior in the mold during casting, it was found that a large amount of molten metal flowed out at the gates located in the runner's end because the runner has a wide cross sectional area with little variation, causing the metal to move downward in order to keep a level surface but which led to the generation of defects. By adopting the runner dimension which gives a uniform flow, which was calculated by using Bernoulli's law, the rejection rate was remarkably decreased. It was also confirmed by experiment that the flow behavior of molten steel from multiple ingates is the same as those of cast iron melt and water.抄録全体を表示PDF形式でダウンロード (637K) -
岡田 明, 三宅 秀和, 尾崎 良平1984 年 56 巻 9 号 p. 527-531
発行日: 1984/09/25
公開日: 2011/11/26
ジャーナル フリーDifferential thermal analysis and thermo-mechanical analysis were performed in white cast irons of the Fe-C system containing carbon up to the eutectic composition by heating at a constant rate. The structures of the irons were examined by quenching after holding at the temperature of either 1,115°C or 1,135°C for a period of up to 2hrs. The white cast iron structure consisting of primary dendrite austenite and ledeburite was changed to a simple mosaic-structure of the austenite and cementite during heating and a minute-endothermic reaction associated with contraction in the irons was observed at about 1,125°C. The minute-endothermic reaction detected was considered to be resulting from the rapid solution of cementite into carbon-deficient austenite in the mosaic-structure at about 1,125°C.抄録全体を表示PDF形式でダウンロード (684K) -
柴田 文男1984 年 56 巻 9 号 p. 532-538
発行日: 1984/09/25
公開日: 2011/11/26
ジャーナル フリーSome investigations were performed for the purpose of elucidating the mechanism of defect formation and method of its prevention when electron beam welding of spheroidal graphite cast iron is carried out. Cracks in welds notably occurred in bead welding for spheroidal graphite cast iron and carbide structure which was extremely hardened was found to be formed in the fusion zone. Further, decrease of carbon and silicon content and increase of sulphur content conceivably have much influence on the generation of cracks. On the other hand, the composition of gas in porosities were mainly CO gas derived from CO reaction. Decrease of carbon content and increase of oxygen content are believed to have much to do on the formation of CO gas. Using an inserting material for butt surface, and selecting suitable welding conditions and performing beam oscillation on the top will result in the prevention of defects and the production of sound and nearly defectless weld.抄録全体を表示PDF形式でダウンロード (823K) -
藤井 恒弥, 今村 哲郎1984 年 56 巻 9 号 p. 539-544
発行日: 1984/09/25
公開日: 2011/11/26
ジャーナル フリーIn earlier reports, the authors have described the basic studies on the adaptability of waste sand dust in foundry for asphalt filler to replace the standard CaCO3 fine power filler materials. But for the practical application of this dust, proof of its quality must been shown in the civil engineering field and conducting a long term proof test. So, by way of a long term practical test, a follow-up study over six years to find out the variation in some specific properties of paved asphalt using dust filler and a comparison with those using a standard filler were conducted. As a result, it was proved that foundry dust could be well adopted as asphalt filler material.抄録全体を表示PDF形式でダウンロード (625K) -
福迫 達一, 久保 公雄, 浅井 裕史, 上山 雅之1984 年 56 巻 9 号 p. 545-552
発行日: 1984/09/25
公開日: 2011/11/26
ジャーナル フリーDeoxidation of copper by phosphorus, aluminum, titanium and lithium additions were investigated by measuring oxygen content using a solid electrolyte. Deoxidation by adding aluminum and titanium were completed within 10 seconds and 300 seconds after stirring the melt, respectively. The oxidation products were Al2O3 and TiO2 which remained in the castings after solidification. The rates of separating and floating of Al2O3 and TiO2 were high, so that the rates of deoxidation were much higher than by adding phosphorus and lithium. In case of phosphorus or lithium addition, the deoxidation rates were controlled mainly by the rates of separation and vaporization of the deoxidation products. It took about 1,200 seconds for deoxidation to be completed. One unit by weight of phosphorus removed less than 1.81 units of oxygen composing of 2Cu2O·P2O5. It was considered that there was a gas phase of P4O10 or a volatile compound of xCu2O· yP2O5 before the formation of 2Cu2O·P2O5. The deoxidation products by adding lithium was considered to be Li2O, but was not observed in the castings after solidification.抄録全体を表示PDF形式でダウンロード (752K) -
野口 徹, 寺田 利昭, 長岡 金吾1984 年 56 巻 9 号 p. 553-558
発行日: 1984/09/25
公開日: 2011/11/26
ジャーナル フリーIn order to evaluate fracture toughness of flake graphite cast iron, JIC test was performed on standard three point bending specimens of FC 15-30 class irons and the implication of the obtained Jin values were discussed based on the J-Δa curves and fracture process observations. The compliance method was used to estimate crack lengths as these are difficult to measure by standard methods.
The J-Δa curves obtained indicate crack extention under small load, and not crack blunting as reported for nodular iron and other metals. Microscopic cracks initiate along graphite flakes around the notch tip and easily propagate in the eutectic cells. From these initial cracks, a macroscopic fracture propagates through the metallic matrix. This occurs at the nodal point in the J-Δa curve. At the nodal point, the load is about 95% of the maximum load and the initial cracks have grown to 0.5-1mm, the order of the cell size. The Jin value of flake graphite cast iron, defined by the nodal point was about 0.5-1.2kgf/mm for FC 15-30 irons, which gives a Kc value (K(Jin)) of 75-125kgf/mm3/2. This K(Jin) value is 20-30% higher than the K(Pmax), 50-100kgf/mm3/2, calculated directly from the maximum load. Considering the ease of estimating, good experimental correlation with K(Jin), and its accuracy on the whole in application, K(Pmax) can be adopted as a safe value for practical purposes although its mechanical implications are not clear.抄録全体を表示PDF形式でダウンロード (726K)
技術報告
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八島 美雄, 木町 信夫1984 年 56 巻 9 号 p. 559-562
発行日: 1984/09/25
公開日: 2015/01/27
ジャーナル フリーPDF形式でダウンロード (1707K)
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