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64 巻, 7 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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呂 傳盛, 陳 立輝1992 年 64 巻 7 号 p. 439-442
発行日: 1992/07/25
公開日: 2011/06/25
ジャーナル フリーSpheroidal graphite cast iron is one of a typical two phases material with coarse spherical second phase particles of very low stiffness and strength. By regarding the nodule graphites as a load carrier and as to provide notch effect, the linear rule can be proposed in which the Young's modulus and flow stress are linearly proportional to the area fraction of graphite. This study is to model on the Young's modulus and tensile flow stress of spheroidal graphite cast iron. The tensile data of a series of spheroidal graphite cast iron with various matrix structures and area fraction of graphites correlate well with the model. The quantitative understanding of notch effect, related to the development of triaxial stress, which is the major role of graphite nodules were discussed.抄録全体を表示PDF形式でダウンロード (396K) -
辻川 正人, 冨永 正須, 日野 実, 川本 信1992 年 64 巻 7 号 p. 443-448
発行日: 1992/07/25
公開日: 2011/06/25
ジャーナル フリーThe influence of pores on the wear property of Al2O3 particles dispersed Al-Si alloy castings was discussed. Specimens were prepared by the vortex method and casted into graphite moulds. These specimens trapped a certain amount of gas pores corresponded to mixing volume of particles during the fabrication. Vigorous stirring dispersed these bubbles as pin hole defects. Volume fractions of pores were measured and one halves of these castings were HIP treated to eliminate the pores. Macro hardness test and dry slide friction tests revealed the differences between the porous as cast series and the HIP treated series. Observation of pores unveiled that the pores incorporated an aggregation of un-wetted particles in the cavities. The macro hardness of as cast series did not increase with the increase of particles addition, while that of HIP treated series increased with particles addition. On the other hand, composite materials, with or without pores, showed drastic effect on prevention of the sever adhesive wear that was usual for matrix alloy at high sliding speed. Also, there was no advantage of HIP treatment for 10 vol % particle composite compared with as cast specimen. HIP treatments improved the wear rates of 30 vol % composite. The wear rate depended on sliding speed in the same manner for two series of materials, however. From these results it was concluded that the pores increased wear rate only they appeared at sliding surface by suppling un-wetted particles as abrasive, and that this did not alter the mechanism of wear.抄録全体を表示PDF形式でダウンロード (707K) -
天野 遼彦, 鳥山 君彦, 小島 政広, 近藤 三二1992 年 64 巻 7 号 p. 449-456
発行日: 1992/07/25
公開日: 2011/06/25
ジャーナル フリーUsing some bentonite from the different deposits, five batches of bentonite-silica sand-water mixtures, in which contains various proportion of temper water respectively were mulled continuousely by Simpson type sand mixer or an agitator type sand mixer processing in sequential series of procedures of a mulling-drying-water adding. Then the green sand properties of the mixture were studied as mulling advanced. 1) Depending on the mulling progress, the green compressive strength of the mixture enhanced considerably and approached an equilibrium value about the mixture. Maximum of green compresive strength of the mixture sifted to the sides of lower moisture content and lower compactability as the mulling further advanced. For the property changes of the mixtures mentioned above, it is considered that the occurence of green strength is primarily a result from dispersion of aggregate structure in bentonite particles. This conclusion is supported with the result that the methyleneblue adsorption capacity of the mixture increased appreciably. 2) From the methyleneblue adsorption capacity and the moisture content at 35 % compactability of the mixture, which approached to the eqilibrium green compressive strength by the continued mulling respectively, adsorption surface areas of each bentonite were calculated. Surface area were in the ranges of 600∼800cm2 / g bentonite according to the characteristics of bentonites. It was shown that α-cristobalite in bentonite also contributes to water adsorption and occurence of green strength of the mixture.抄録全体を表示PDF形式でダウンロード (659K) -
呂 傳盛, 丁 泰安, 陳 立輝1992 年 64 巻 7 号 p. 457-461
発行日: 1992/07/25
公開日: 2011/06/25
ジャーナル フリーThe tensile deformation behavior of austempered spheroidal graphite cast iron were investigated by varying test temperature (from 300 K to 873 K) and strain rate. The microstructure of the materials used in this study is upper bainitic structure, typically consisted of bainitic ferrite and retained austenite. But after holding or testing at elevated temperature, the retained austenite decreased rapidly from about 25 % at 300 K to almost 0 % at 770 K. Therefore, for understanding the tensile character of this material, the study were carried out by using tensile test, optical microscopy, scanning electron microscopy and X-ray diffraction analysis. The results reveal an inverse dependence on test temperature below 550K, and also on the strain rate at about 473 K are worthy to notice. Based on the experimental data, the dominant factors of above-mentioned phenomenon were clarified and discussed in this report.抄録全体を表示PDF形式でダウンロード (639K) -
長坂 悦敬, 那智 雅博, 木口 昭二, 大中 逸雄1992 年 64 巻 7 号 p. 462-468
発行日: 1992/07/25
公開日: 2011/06/25
ジャーナル フリーA numerical analysis technique to predict microstructure of austempered ductile cast iron has been developed. In this technique, heat balance equation is solved by the Direct Finite Difference Method. The cooling curves of each element are compared with CCT diagrams to know the start time of phase transformation. Once the phase transformation begins, the volume percentage of each phase during continuous cooling can be calculated by using TTT diagrams. Furthermore, a parameter to predict hardness distribution of a thick austempered casting is proposed. To verify this numerical analysis technique, test pieces with different thickness and alloying elements have been cast and austemperd in salt bath and fluidized bed. The predicted microstructure agreed well with experimental results. The numerical anaysis can be applied as an effective tool to optimize austemper condition for the practical ductile iron casting.抄録全体を表示PDF形式でダウンロード (748K) -
鈴木 俊夫, 小林 史典, 土田 保1992 年 64 巻 7 号 p. 469-475
発行日: 1992/07/25
公開日: 2011/06/25
ジャーナル フリーA method for the evaluation of primary dendrite arm spacing using the Fourier transform has been proposed. The accuracy of the measurement is checked using 2-dimensional lattice point models whose latice spacings are normaly distributed. By the Fourier transform, the latice spacing can be evaluated within the error less than 2 % . Existence of vacancies in the model patterns does not affect the determined values of spacings. The standard deviation of latice spacings is also qualitatively estimated by measuring the half width of the maximum spectrum peak in the transformed image. Primary dendrite arm spacings of unidirectionally solidified copper 8 mass % tin alloy are measured by the Fourier transform method. The results show that there exists a principal spacing at the position with the same solidification conditions even when the apparent local dendrite spacings are different.抄録全体を表示PDF形式でダウンロード (715K)
技術報告
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福田 宗弘, 鈴木 喜好, 橋本 邦弘1992 年 64 巻 7 号 p. 476-483
発行日: 1992/07/25
公開日: 2015/01/22
ジャーナル フリーPDF形式でダウンロード (3680K) -
干場 俊昌1992 年 64 巻 7 号 p. 484-490
発行日: 1992/07/25
公開日: 2015/01/22
ジャーナル フリーPDF形式でダウンロード (3239K)
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