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67 巻, 11 号
選択された号の論文の8件中1～8を表示しています
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研究論文
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糸藤 春喜, 山田 肇1995 年 67 巻 11 号 p. 767-774
発行日: 1995/11/25
公開日: 2011/03/25
ジャーナル フリーIn this paper, the author puts forward a new proposal relating to the nucleation and growth mechanism of spheroidal graphite in magnesium-treated cast irons. The new theory is named the site theory. The site theory can explain the nucleation and growth mechanism for not only spheroidal graphite but also all other forms of graphite in cast irons. A magnesium map of the microstructure was analyzed using EPMA in conjunction with a coloured mapping display system. A Mg halo was found as a segregation around the spheroidal graphite nodules. Although inclusions were observed within some graphite nodules. each also had Mg halo. The Mg halo suggests that Mg gas bubble played the role of the nucleation and growth site for spheroidal graphite. The results were considered sufficient to prove the site theory.抄録全体を表示PDF形式でダウンロード (948K) -
旗手 稔, 塩田 俊雄, 炭本 治喜, 中村 幸吉1995 年 67 巻 11 号 p. 775-781
発行日: 1995/11/25
公開日: 2011/03/25
ジャーナル フリーThe average coefficient (α) of Iinear thermal expansion of low-expansion flake and spheroidal graphite cast irons with 35 mass % Ni-1.8 mass % C-1.2 mass % Si, subjected to heat treatment under different conditions, was measured in the temperature range from 323 K to 773 K. When the cast irons were subjected to solution treatment or annealing at the temperature range from 873 K to 1373 K for 3.6 ks, the values of α at 373 K decreased with elevating the heat treatment temperature. The cast irons annealed at 1273 K for 3.6∼360 ks showed a decrease in the value of α at 373 K with increasing the holding time. It was concluded that such a decrease in α was caused by the homogenization of nickel in austenite.抄録全体を表示PDF形式でダウンロード (678K) -
中江 秀雄, 勝山 利広1995 年 67 巻 11 号 p. 782-787
発行日: 1995/11/25
公開日: 2011/03/25
ジャーナル フリーShape of flake graphite in cast iron was so complicated that the real three dimensional morphology could not be understood in general. Influence of the graphite morphology on the tensile strength of cast iron had not been analyzed sufficiently. In this paper, we would like to discuss the influence of co-existence A-type with D-type graphite on the tensile properties of cast iron. For the investigation of graphite morphology on tensile properties, we changed the graphite morphology by using inoculation, Ti addition and holding of melt in furnace, and then, these samples were fully annealed into ferrite. The stress-strain curves of these specimens were measured and we concluded the experimental results as follows, (1) D-type graphite sample surpassed in tensile strength than that of A-type samples, but were inferior in elongation than that. (2) The tensile properties of samples were decreased not only tensile strength but elongation by the co-exitence of A-type graphite with D-type graphite. (3) The influence of the co-existence in graphite types explained by the Rule of Mixtures in tensile strength for fiber reinforced composites (F. R. C).抄録全体を表示PDF形式でダウンロード (554K) -
辻川 正人, 冨永 正須, 日野 実, 川本 信1995 年 67 巻 11 号 p. 788-793
発行日: 1995/11/25
公開日: 2011/03/25
ジャーナル フリーWear characteristics of metallic materials can be greatly improved by the dispersion of ceramics particles. The relation of dispersed particles fraction and wear is still not clear but this subject is of close relation to the friction and wear mechanism of hard particles dispersion composites. In this study, alumina particles dispersion aluminum alloy composite castings were made by the vortex method and investigated by a pin on disc tribo-tester under dry condition. It was found that at all sliding speeds (from 0.1 m/s to 3.0 m/s), wear rates of the composite pin specimens and mated steel discs increased as the fraction of dispersed particles increased. The investigation of sliding surface and wear debris clarified the steps to the wear mechanism of composites. These are, the fracture of alumina particles at sliding surface, stacking of debris on the composite surface and falling off of stacked layer. The increase in particles fraction increases the frequency of particles fracture and causes the stacking layer to become thick and easy to peel off.抄録全体を表示PDF形式でダウンロード (811K) -
米田 隆志, 佐藤 敬, 新山 英輔1995 年 67 巻 11 号 p. 794-799
発行日: 1995/11/25
公開日: 2011/03/25
ジャーナル フリーIn order to obtain quantitative information for designing risers of the titanium alloy castings induction-melted in lime crucibles, their volumetric changes occurring during solidification and cooling processes were measured and compared to those of aluminum, iron and 18 % Cr-8 % Ni steel. The measured internal and external shrinkage ratios approximately agreed with the known solidification and solid shrinkages, respectively. The values of 3.5 % for commercially pure titanium, 4.5 % for Ti-6 % Al-4 % V and 5.5 % for Ti-15 % V-3 % Al-3 % Cr-3 % Sn alloys were tentatively determined as the apparent solidification shrinkage. The usefulness of those data for determining the minimum riser size required to make shrinkage-free castings was confirmed using the theoretical equation of Adams and Taylor as a criterion. The solidification and shrinkage characteristics and risering requirements of the titanium alloys are closer to those of 18 % Cr-8 % Ni steel rather than those of aluminum.抄録全体を表示PDF形式でダウンロード (681K) -
新井 浩, 辻村 太郎, 清水 保雄1995 年 67 巻 11 号 p. 800-806
発行日: 1995/11/25
公開日: 2011/03/25
ジャーナル フリーIn the rolling stock, wear resistance of the cast iron brake shoe has been improved by adding phosphorous. We reported the effects of phosphorus on the friction qualities of the brake shoe. It is not necessarily desirable that the brake shoe be used as a substitute for the present brake shoe, because phosphorus effects the frictional coefficient of the brake shoe. In 1985, a brake shoe added with chromium was developed, and the life of the brake shoe became 2.5∼5 times longer than that of the conventional brake shoe without influencing the frictional coefficient of the brake shoe. In this study, a brake shoe added with chromium to an extent of 5 mass % was produced, and the effects of chromium on the frictional wear of the cast iron brake shoe were studied using a full-scale braking tester and a friction tester. The effctive chromium content which contributed to wear resistance improvement of the brake shoe was approximately 1∼2 mass %. Correlation between the wear rate and the form of the worn particles was seen. The frictional coefficient of the brake shoe dropped slightly as the chromium content increased.抄録全体を表示PDF形式でダウンロード (994K) -
楊 弋涛, 野村 宏之, 滝田 光晴1995 年 67 巻 11 号 p. 807-812
発行日: 1995/11/25
公開日: 2011/03/25
ジャーナル フリーIt is well known that the inclusion removal process plays a key role in casting quality control. The use of ceramic foam filter has grown substantially over the past few years. In this study the pouring time, runner flow rate, and pressure head drop through runner were predicted with a simple model. A filter sizing model was used to obtain the reasonable casting conditions. They were examined by water model and practical pouring experiments. The effective combination of the application of these models with reasonable designs of the gating system provides the basis for the optimization of the inclusion removal process of molten metal at appropriate casting rates.抄録全体を表示PDF形式でダウンロード (529K)
技術報告
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大出 卓, 亀島 憲一, 近藤 幸一, 芝地 豊1995 年 67 巻 11 号 p. 813-819
発行日: 1995/11/25
公開日: 2015/01/21
ジャーナル フリーA new melt combination process which can continuously control the graphite morphology from spheroidal to flake in cast iron was developed by improving Inmold process. Two reaction chambers were prepared in one sand mold. One reaction chamber was used for spheroidizing melt, and the other one for inoculating melt. After pouring into the sprue, the molten iron of the given chemical composition was separated and passed through each reaction chamber. The separated melts were collided with each other and filled into the cavity. As the result, a new functional iron material, one side of which has the specific properties of the spheroidal graphite cast iron, and the other side of which has those of the flake graphite cast iron, was produced without difficulty. This typical graphite structure could be produced using sub-tools such as filters, dams and chillers.抄録全体を表示PDF形式でダウンロード (3522K)
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