巻号一覧
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50 巻, 1 号
選択された号の論文の6件中1～6を表示しています
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研究論文
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千田 昭夫, 瀬谷 修, 目黒 勝, 高橋 宥夫1978 年 50 巻 1 号 p. 2-7
発行日: 1978/01/25
公開日: 2012/06/02
ジャーナル フリーTo make clear the merit of pig iron used in melting by low frequency induction furnace, influences of the kind of pig iron and its charge time on melting were examined. The later the pig iron was charged into the molten steel scrap, the better was the property of cast iron. This seems to be the result of improved freezing manner of the steel due to the suspended carbon from the pig iron in the molten steel scrap. The properties of cast iron were dependent on the kind of pig iron, and some properties were much influenced by the charge time of pig iron. The properties of cast iron combined with pig iron to make ductile cast iron were remarkable and the graphite in the pig iron, especially the ratio of graphitization contributed to this improvement.抄録全体を表示PDF形式でダウンロード (797K) -
木口 昭二, 佐藤 博之, 加山 延太郎1978 年 50 巻 1 号 p. 8-13
発行日: 1978/01/25
公開日: 2012/06/02
ジャーナル フリーViscosity and fluidity of molten metals in the early stages of solidification are estimated to be closely related to the crystallization behavior of primary crystals. Hypo- and hyper- eutectic Al-Si alloys were examined to elucidate more clearly the effect of shape and size of primary crystal on viscosity and fluidity. The fluidity of hypo-eutectic Al-Si alloys is poor compared to hyper-eutectic ones. This is attributable to the fact that the hypo-eutectic alloys crystallize complicated shape of dendrites. The fluidity of hypo-eutectic alloys lowers as the primary dendrite becomes finer. This is explained by the fact that the viscosity of the molten metal suspending fine crystals is larger. That is, a general reciprocal relation between fluidity and viscosity is established in hypo-eutectic alloys. The fluidity of hyper-eutectic alloys lowers as the primary silicon crystals coarsen. At the same time, the viscosity lowers. But the viscosity at this time has lost its meaning as a physical property. Thus, the lowering of fluidity in this case is understood to be brought about by increased flow resistance with coarse crystal grains.抄録全体を表示PDF形式でダウンロード (764K) -
山本 治, 山田 博之, 斎藤 誠宏1978 年 50 巻 1 号 p. 14-19
発行日: 1978/01/25
公開日: 2012/06/02
ジャーナル フリーA comparison of two nobake binders (low-nitrogen furan and oil-urethane) is presented. The discussion centers around effects of different sands, hot compressive strength and gas evolution. Twenty four hour compressive strengths were studied at catalyst levels which produce strip times in the range of 45-60min. Furan binder exhibits stronger adhesive strength at the binder-sand interface, and wets the sand surface more easily than urethane binder. This is the reason why furan binder is sensitive to the nature of sand grains. To reduce the binder level, dry sand reclamation which retains the smooth resin film on the sand grains is recommended. The lower hot strength of urethane binder is explained based on the level of residual carbon which is calculated from the gaseous decomposition products derived from resins upon exposure to 1,000°C. Furan core has larger H2O (cal.50%) and less H2 and hydrocarbons as compared with urethane core. During 4 min of exposure at 1,200°C, urethane core generates 90% of the total gas whereas the furan core produces only 50% of the gas, However, during 8 min of exposure at 400°C, urethane core exhausts only 40% of gas, while furan core emit 80% of gas.抄録全体を表示PDF形式でダウンロード (782K) -
片島 三朗, 松浦 誠1978 年 50 巻 1 号 p. 20-25
発行日: 1978/01/25
公開日: 2012/06/02
ジャーナル フリーMechanism of molding sand compaction by squeezing was theoretically investigated. The state of stress in the mold during squeezing was interpreted based on the theory of plasticity, assuming that the compacting molding sand mass is in a state of plastic equilibrium. The plastic analysis used in soil mechanics is demonstrated to apply to the compaction of molding sand, and the distribution of stress in the mold was calculated numerically. The calculated results show fair quantitative agreement with the experimental results.抄録全体を表示PDF形式でダウンロード (658K) -
上田 俶完, 和出 昇, 原 良1978 年 50 巻 1 号 p. 26-31
発行日: 1978/01/25
公開日: 2012/06/02
ジャーナル フリーIn the early stage of ferritizing of cast irons, contraction is observed instead of expansion, which generally results from the graphitization of cementite. Using the dilatometric method, the conditions giving rise to contraction and mechanisms operating on this phenomenon were investigated. The contraction in ferritizing is affected remarkably by the thermal history. In the pearlitic cast iron, which is austenitized from ferritic iron and then air cooled, the early stage contraction in ferritizing is very distinguished and the final expansion is very little. The contraction becomes gradually remarkable changing from flaky to spheroidal graphite, and the lower the silicon content is, the more contraction is obtained. This phenomenon is explained to be as follows; in the austenitizing of ferritic cast iron, the graphite becomes porous due to the increasing vacancies formed by the Kirkendall effect, which results in the observed expansion. The porosities are retained in air cooled iron and decrease as carbon from graphitizing of cementite fills the porosities during the ferritizing process This results in contraction.抄録全体を表示PDF形式でダウンロード (714K) -
川本 信, 足立 雅彦, 安藤 繁, 岡林 邦夫1978 年 50 巻 1 号 p. 32-37
発行日: 1978/01/25
公開日: 2012/06/02
ジャーナル フリーBoth the temperature of real contacting asperities (the flash temperature) and the mean temperature of the apparent sliding surface were considered. It is assumed that the former is related to the formation of adhesive junction and the strength of its interface, while the later is a guideline of the temperature at site of adhesive junction to be sheared. Regardless of sliding condition and matrix structure, when the flash temperature is from 300°C to 500°C, the mechanical destructive wear, which is one form of the severe wear, appears and this wear rate slightly decreases with rise in the mean temperature. That the range of sliding speed where the mechanical destructive wear occurs increases with the amount of ferrite in the matrix structure depends on the fact that the sliding speed for the flash temperature to become 300°C−500°C extends because of decrease in hardness of the matrix structure. Drastic seizure appears when the mean temperature is above 400°C. There is a close relation between seizure and mean temperature and they depend on each other.抄録全体を表示PDF形式でダウンロード (769K)
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