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67 巻, 1 号
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研究論文
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水上 秀昭, 加藤 彰, 坂田 直起, 星田 達男, 土田 裕1995 年 67 巻 1 号 p. 3-8
発行日: 1995/01/25
公開日: 2011/06/11
ジャーナル フリーInvestment castings of C. P. titanium and titanium alloys, and die-casting of aluminum alloys are near-net-shape technologies for complex shape parts and hard workable materials. The yield of thin wall castings less than 1 mm thickness decreases with decreasing wall thickness. The effect of casting conditions such as atmospheric pressure, mold pre-heating temperature, and centrifugal force on filling ability in the lost wax process was studied using experimental casting equipment. The following results were obtained. (1) A reduced pressure is needed for better filling ability. (2) Centrifugal force which overcomes surface tension is needed for better filling ability. (3) Filling ability can be evaluated using “Fluidity” which is the length of the metal flow before it is stopped by solidification. (4) The filling ability of titanium alloy is inferior to those of aluminum and Ni-base superalloys.抄録全体を表示PDF形式でダウンロード (566K) -
丸 達彦, 野村 宏之, 王 承志, 寺嶋 一彦1995 年 67 巻 1 号 p. 9-15
発行日: 1995/01/25
公開日: 2011/06/11
ジャーナル フリーIt is necessary to avoid entrapment of air and inclusions during metal casting in order to prevent formation of casting defects. Large-size inclusions, in particular, yield serious problems concerning casting quality. To solve the problem of inclusion defect in the products, it is quite important to know movement and trajectory of inclusion from which information can be given on the countermeasure for inclusion entrapment. With the above point of view, this study dealt with the model experiments and the computer simulation on inclusion movement during melt filling in mold cavity. In the experiments, inclusion trajectory in the mold cavity was obtained under the various conditions of timing and location at the gate of inclusion inflow. The experimental results were explained reasonably by the model of fluid dynamics. Furthermore finally entrapped position of inclusions in castings was predicted by the model combined with solidification anlaysis. The present study affords a basic idea to CAE (Computer Aided Engineering) on inclusion-free casting production.抄録全体を表示PDF形式でダウンロード (669K) -
楊 錦成, 曹 申, 蘇 国璋1995 年 67 巻 1 号 p. 16-19
発行日: 1995/01/25
公開日: 2011/06/11
ジャーナル フリーA foamed aluminum can be produced by adding aluminum powder and titanium hydride to molten Al-7 % Si alloy and by heating the mixture to decompose the titanium hydride to evolve gas. In this case, the addition of powdered aluminum to the Al-7 % Si alloy melt raises the viscosity of the molten solution and effectively retains the gas from thermal decomposition of titanium hydride in the melt. The optimum torque value of the melt stirring was about 0.3 N⋅m. A homogeneously foamed aluminum with the porosity of about 87 % was obtained.抄録全体を表示PDF形式でダウンロード (489K) -
揚 錦成, 闕 山璋1995 年 67 巻 1 号 p. 20-23
発行日: 1995/01/25
公開日: 2011/06/11
ジャーナル フリーThe foaming factors of foamed aluminum were investigated by a gas foaming process. 0.5 to 2.5 % powdered titanium hydride containing Al-7 % Si-0.45 % Mg alloy as the base material was added to the molten aluminum alloy as a foaming agent to adjust to the optimum agent amount. Furthermore foaming conditions were controlled in the temperature range from 893 K to 943 K, and in the time range from 0 s to 600 s to determine the optimum foaming process for obtaining homogeneous foamed material. As a result, the optimum foamed aluminum with air bubbles of 2 mm to 5 mm diameter and homogeneous distribution was obtained by adding 1.5 % titanium hydride at a foaming temperature of 913 K and in a foaming time of 180 s to 360 s.抄録全体を表示PDF形式でダウンロード (697K) -
松田 政夫, 頃安 貞利, 横山 康雄1995 年 67 巻 1 号 p. 24-29
発行日: 1995/01/25
公開日: 2011/06/11
ジャーナル フリーThe solidification time of cylindrical sand castings with adjacent castings or riser was numerically simulated by three-dimensional solidification analysis. The solidification time of a row of cylindrical casting increases with decreasing ratio of pitch to cylinder diameter, and it is about three times that of a single cylindrical casting in the case where cylinders are arrayed touching with each other. While the effect of heat transfer from adjacent castings on solidification time is not significant when the rato is more than 1.7. The solidification time at the last solidified part of the cylindrical casting with typical riser arrayed touching with the casting is about 1.5 times that of a single cylindrical casting without riser, and the effect of the distance between casting and riser is not singnificant.抄録全体を表示PDF形式でダウンロード (620K) -
新山 英輔, 安斎 浩一1995 年 67 巻 1 号 p. 30-36
発行日: 1995/01/25
公開日: 2011/06/11
ジャーナル フリーOne-dimensional heat flow simulation of solidification was performed to examine the behavior of solidification velocity V and temperature gradient at solidification G, both of which are major variables governing various phenomena including shrinkage formation. In the solidification of semi-infinite solid of pure metals or alloys, G/V ratio is constant and acceleration of solidification is not observed. The same applies to pure metal plates of finite thickness. In alloy plates of finite thickness, V increases near the center, and hence, G/V ratio decreases. The beginning point of the decrease is nearer to the surface in sand mold castings than in metal mold castings. The point of decrease in aluminum alloy castings is nearer to the surface than in steel castings. G/V ratio is a function of the relative distance from the surface, independent of the casting thickness. In cylindrical castings, acceleration is always observed for both pure metal and alloy.抄録全体を表示PDF形式でダウンロード (622K) -
仲井 宏和, 星加 洋, 松村 嘉高1995 年 67 巻 1 号 p. 37-42
発行日: 1995/01/25
公開日: 2011/06/11
ジャーナル フリーThe joining of cast iron (FC 200) to Al2O3 ceramics with Al filler metal was conducted in a vacuum. Al2O3 surfaces were coated with 0.5 μm copper film by means of vacuum evaporation method to increase the wettability of Al2O3 by molten Al. Joint strengths were evaluated in relation to the brazability of Al2O3 and the growth of intermetallic compound layers formed between filler metal and cast iron. The results are summarized as follows. (1) A reaction between molten Al and Cu film on Al2O3 enhances the driving force for wetting of Al2O3 by filler metal. (2) The maximum shear strength of the joint is slightly larger than Al2O3-mild steel joint. (3) The formation of interlayers between cast iron and molten Al is not affected substantially by Si and graphite contained in cast iron.抄録全体を表示PDF形式でダウンロード (610K) -
菅野 利猛, 中田 毅1995 年 67 巻 1 号 p. 43-48
発行日: 1995/01/25
公開日: 2011/06/11
ジャーナル フリーIn gray cast irons, the presence of small amounts of lead may contribute to the formation of undesirable types of graphite, such as Widmänstatten, spiky, or mesh like graphite. The object of this work is to investigate the influences of lead on the mechanical properties and microstructures of gray cast irons. Melted gray cast irons, with various contents of lead, were poured into 30-80 mm diameter bars. The addition of lead was found to increase the hardness, chill depth, and amount of undesirable graphite in the gray cast iron. Also, the addition of lead was found to decrease the tensile strength of gray cast irons. In heavy castings, such as the 80 mm diameter specimen, the harmful effects of lead were more easily recognized.抄録全体を表示PDF形式でダウンロード (896K) -
武 宏強, 笹栗 信也, 橋本 光生, 松原 安宏1995 年 67 巻 1 号 p. 49-55
発行日: 1995/01/25
公開日: 2011/06/11
ジャーナル フリーType and three-dimensional morphology of carbides precipitated in as-cast multi-component white cast irons, which contain 5 % Cr, 1-8 % Mo and W, 1-15 % V, 0-12 % Co and 1.3-3.2 % C, were investigated using an optical microscope, SEM and X-ray diffraction. The types of carbide are MC. M2C and M7C3. Morphology of the MC carbide is classified into three of petal-like, nodular and coral-like types. The M2C carbide is classified into two of lamellar and coarse plate-like types, and the morphology of M7C3 is rod-like or ledeburitic type. The type and morphology of carbides varies remarkably depending on chemical composition of iron, particularly carbon and vanadium, and tungsten equivalent (Weq), when chromium and cobalt contents are constant. However, they are not changed by cobalt content. Region of chemical compositions in which each type of carbide precipitates is expressed by simple equations in relation to the contents of carbon and vanadium and Weq.抄録全体を表示PDF形式でダウンロード (1016K)
解説
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井川 克也1995 年 67 巻 1 号 p. 56-61
発行日: 1995/01/25
公開日: 2015/01/21
ジャーナル フリーPDF形式でダウンロード (2319K)
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