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60 巻, 5 号
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技術報告
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片岡 義博, 樋口 正司, 村井 香一1988 年 60 巻 5 号 p. 297-300
発行日: 1988/05/25
公開日: 2015/01/27
ジャーナル フリーHigh manganese cast steel was prepared in a high frequency induction furnace, using steel scrap and ferromanganese as raw materials. Effects of mischmetal additions on the mechanical properties and cast structure were investigated by measuring tensile strength, elongation and grain size of austenitic structure. Results are summarized as follows. 1) 0.01% mischmetal addition results in the highest mechanical properties. 2) The grain size of austenitic structure becomes finer with increasing mischmetal addition. 3) Mechanical properties, however, begin to decrease at the mischmetal addition of 0.02%. The decrease is even larger at and above 0.05% addition.抄録全体を表示PDF形式でダウンロード (1776K)
研究論文
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中澤 哲夫, 森本 庄吾, 酒井 淳次1988 年 60 巻 5 号 p. 301-306
発行日: 1988/05/25
公開日: 2011/09/08
ジャーナル フリーThe authors pointed out earlier a possibility of using aquous solution of alkali neutralized copolymer of isobutylene and maleic anhydride as a binder for CO2 gas hardening rapid molding process. Characteristics of binders which were neutralized by different kinds of alkali compounds were examined. Viscosity of binders were different depending on the combination of copolymer and alkali compound. The LiOH neutralized binder showed the highest viscosity, followed by NaOH, KOH and NH3 neutralized binders, in the decreasing order. This order of viscosity corresponds to the order of the lyotropic series of cation (Li+, Na+, K+, and NH4+). The pH values of the binders and reactivity of the binders with CO2 gas were independent of the kind of alkali compounds. With mold using LiOH neutralized aquous solution as the binder, strength of the mold immediately after CO2 gas blowing was 85 N/cm2, showed the highest among the binders. When KOH and NaOH neutralized dinders were used, mold strength was 56 and 35 N/cm2, respectively.抄録全体を表示PDF形式でダウンロード (680K) -
斎藤 和夫, 太田 実1988 年 60 巻 5 号 p. 307-312
発行日: 1988/05/25
公開日: 2011/09/08
ジャーナル フリーThe authors analyzed the heat transfer phenomena in the preheat zone of cupola by using a model. In this paper, effects of shape and charge material composition on the melting efficiency are described. To model a condition similar to the cupola operation, steel of spherical, cylindrical and rectangular shapes was used as charge material for comparing the difference in the heat absorption behavior. In another series, graphite was used together with steel ball to simulate a coexisting condition. Heat absorption behavior was examined by blowing hot gas into the packed bed. When changing the shape of steel, with surface area kept constant, heat accumulation was faster with increasing specific surface area as expected. Further, when the specific surface area and the heat receiving area of the packed bed were kept nearly constant, heat absorption was almost the same, independent of the charge shape. This fact can be used as a basis for determining the optimal cupola charge.
To study the influence of charge composition in the preheat zone, graphite was placed near the bottom and steel balls near the top. Heat accumulation of graphite was fast due to its higher heat conductivity and lower heat capacity, resulting in a higher heat absorption rate by the steel. Heat absorption rate was lower, when steel balls and graphite were uniformly mixed. The results of this model indicate that a “layer by layer ” charging is effective for obtaining a high melting efficiency in cupola melting.抄録全体を表示PDF形式でダウンロード (681K) -
高橋 忠義, 工藤 昌行, 大笹 憲一, ファルーク セディキ1988 年 60 巻 5 号 p. 313-319
発行日: 1988/05/25
公開日: 2011/09/08
ジャーナル フリーFeeding behavior in the processes of unidirectional and cylindrical solidification of Al-3mass%Si alloy ingots was examined by measuring the change in height of a hot top. A method for accurately measuring the surface fluctuation of the hot top was devised by the authors. The surface of the hot top starts to fall rapidly as the molten metal at the bottom of the mold initiates to solidify. The fall is suppressed immediately after the top of the ingot reaches the temperature corresponding to the fraction solid of 0.67.
Densities of liquid and solid necessary for the analysis of the feed behavior were determined. The ingot was partitioned into minute volume elements for the analysis, and “ feed components ” were evaluated in the range from liquid state to solid state via liquid-solid transformation, from the density change with the lapse of time after pouring. Feeding consists of the following components for compensation of contraction ; thermal contraction in the complete liquid and complete solid, solidification contraction below and above the fraction solid of 0.67, and thermal contraction of the hot top. The value of 0.67 is the limit of feeding possibility. A comparison of the feeding curve obtained by summing the quantities of those components and measured one shows a good agreement in the range of the feed.抄録全体を表示PDF形式でダウンロード (788K) -
安江 和夫, 西尾 敏幸, 山田 康雄, 近藤 靖彦1988 年 60 巻 5 号 p. 320-325
発行日: 1988/05/25
公開日: 2011/09/08
ジャーナル フリーNodular cast iron was cast into metal mold to study occurrence of defects similar to seams, while varying casting conditions such as chemical compositions of molten metal, pouring temperature, gating systems and coating materials. Detailed investigation was made on the relation between the seams and the dilatation by graphitization at the eutectic solidification which has so far been believed to be the cause of seams. As a result, however, no apparent relation was observed. In an experiment on seams using bismath, it was found that the occurrence of seams decreased when rouge was used as a mold coating material. Therefore, it was suggested that the viscosity of molten metal and the interfacial tension between molten metal and mold were closely related with the seam formation.抄録全体を表示PDF形式でダウンロード (750K) -
米倉 浩司, 山本 善章, 中村 元志, 平野 春好, 成瀬 賢次1988 年 60 巻 5 号 p. 326-331
発行日: 1988/05/25
公開日: 2011/09/08
ジャーナル フリーGating systems commonly used for automobile castings are mainly composed of linear runners, such as L-shaped or reverse T-shaped runners. A stuby has been made on the amount of flow through multi-ingates in these gating systems using Bernoulli’s theorem.
When the gaing systems can be considered to be filled with molten metal, the amount of flow through each gate can be calculated from the theory that the sum of losses, including the loss by friction, the loss at bending, the loss due to the cross sectional area change and the velocity heads of metal flow through gates, will be equal to the energy determined by the height of the sprue.
The loss coefficients of bending and choking were obtained by measuring the pressure loss of water flow poured into a plastic tube. These loss coefficients can be used as the loss coefficients of the flow in calculating the amount of flow of molten metal.
The loss coefficient of bending at the sprue bottom and that on the horizontal plane take the values of 1 to 4 and 1 to 2.5, respectively. The loss coefficient at 50% stepwise areal reduction takes the value of 0.2.抄録全体を表示PDF形式でダウンロード (652K) -
田中 雄一, 今 宗由, 平岡 武1988 年 60 巻 5 号 p. 332-337
発行日: 1988/05/25
公開日: 2011/09/08
ジャーナル フリーA thin surface layer of flake graphite cast iron was once melted by applying inert gas tungsten arc (TIG) and solidified to form a hardened chill layer. The amount of pores which remained in the remelted zone was increased with increasing silicon content while carbon content was kept constant, i. e. with increasing carbon equivalent. It was suggested that the pores were produced by CO gas formed by reducing SiO2 with carbon in a temperature range higher than the criticall point of CO-SiO2 equilibrium. As high temperature melting remarkably decreases SiO2 formation, evolution of CO gas can be decreased during high temperature TIG arc remelting and thus the amount of pores can be reduced. An addition of aluminum was particularly beneficial for the remelting practice, because aluminum has a high ability of reducing SiO2 and its reaction product is not reduced during remelting.抄録全体を表示PDF形式でダウンロード (794K)
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