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51 巻, 11 号
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研究論文
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松田 政夫1979 年 51 巻 11 号 p. 627-632
発行日: 1979/11/25
公開日: 2012/06/02
ジャーナル フリーTemperature distribution in molten metal is calculated by rapidly converging infinite series, with a casting plate having uniform thickness T and molten metal flowing at constant velocity inside the already solidified metal layers. In the range where the dimensionless Fourier number τ is less than 0.2, the average temperature of the molten metal θm is approximately expressed by the solution of the Fourier equation with error functions as follows :
θm−θf=(θp−θf) {1−(2/√π)√τ}
where θp is the initial temperature of the molten metal and θf is the freezing point. In the range where τ is greater than 0.2, θm is approximately expressed by the solution of the equation with trigonometrical functions as follows :
θm−θf=(θp−θf) exp {−(π/2)2(τ+0.0851)}
Calculation errors of these expressions from the theoretical solutions remain less than 0.2%. The portion of heat energy over the freezing point is reduced to half during the flow from the entrance to the position which correspond to where τ is 0.197. That portion of heat energy is reduced to half every 0.281 Fourier number in the range where τ is greater than 0.197. A range where the once-formed metal layers have been remelted always exists near the entrance even though the duration of the molten metal flow may be short.抄録全体を表示PDF形式でダウンロード (701K) -
安江 和夫, 磯谷 三男, 近藤 靖彦1979 年 51 巻 11 号 p. 633-637
発行日: 1979/11/25
公開日: 2012/06/02
ジャーナル フリーStress-strain curve of gray cast iron (JIS-FC25) and ductile cast iron (JIS-FCD45) were measured under tensile and compressive stresses from room temperature up to 700°C. The non-linear character of stress-strain curve was considered to be dependent on elastic deformation and elastic-plastic deformation of void occupied by graphite. From this point of view, the stress which start to yield at the concentrated area of stress was estimated by cyclic load method. The value of that stress was confirmed to be acceptable on comparison with yield stress of Fe-2.91%Si alloy. Furthermore, the measurement of that stress by Acoustic Emmision was tried, and a continuous type of AE accompanying enlargement of the yield region was observed.抄録全体を表示PDF形式でダウンロード (650K) -
千々岩 健児, 畑村 洋太郎, 淵上 正朗1979 年 51 巻 11 号 p. 638-642
発行日: 1979/11/25
公開日: 2012/06/02
ジャーナル フリーThe usual methods of sand molding are jolt and jolt-squeeze but the former makes a big noise and there is also a lot of vibration, while in the latter there is a defect that pressure cannot be transmitted easily to the deep parts. It is therefore necessary to find a new method to solve these problems. A basic research for compaction of powder which has been conducted in the laboratory revealed that lateral vibration was very effective for compaction of powder. Thus an experimental molding machine was made to test the effect of lateral vibration on sand molding. In this machine, the pattern and the molding flask move in a parallel circular motion on a horizontal plane. They move in the same direction and have the same amplitude (0.15mm, peak to peak) and frequency (100Hz). Some parameters, such as the height of molding flask, the height of pattern and the squeeze pressure, are varied to see the hardness distribution in the mold.
The hardness of the mold is increased by the vibration, and it is particularly remarkable when the squeeze pressure is low and the molding flask is high. The hardness of the mold increases with the increase of the amplitude of the vibration. It is most desirable to apply squeeze pressure and vibration at the same time. The noise of the machine is very low, and the vibration on the ground is completely insulated by vibration proof rubber.抄録全体を表示PDF形式でダウンロード (612K) -
片島 三朗, 田島 俊造1979 年 51 巻 11 号 p. 643-647
発行日: 1979/11/25
公開日: 2012/06/02
ジャーナル フリーIn order to elucidate the movement of the moisture condensed layer and heat transfer of green sand mold, accurate moisture content values are required. A new moisture determining method was established. The method involves picking up 22 samples from a mold, cooling them in liquid nitrogen, and then weighing them before and after drying. Accurate moisture values were obtained at all measured points in the layer. In the transportation zone, moisture distribution was uniform regardless of the mixing ratio or the initial mold temperature. Transportation zone and the part where the temperature is 100°C in the thermal gradient of green sand mold just after pouring appeared at the same site. The boundary of dry-out zone/transportation zone was very clearly recognized. It is considered that heat transfer in green sand mold up to 100°C is mainly dependent on latent heat in the moisture.抄録全体を表示PDF形式でダウンロード (631K) -
大城 桂作, 長沢 憲一, 松田 公扶1979 年 51 巻 11 号 p. 648-654
発行日: 1979/11/25
公開日: 2012/06/02
ジャーナル フリー15%Cr and 30%Cr eutectic cast irons with about 1%Mo, V, Ni or Si additions were quenched by water spray during freezing at 10mm/hr unidirectionally. The distribution of the elements in the melt and eutectic cell was investigated using electron probe microanalyzer. The composition of the eutectic carbide and austenite was analyzed with the finely focused electron beam, and the average composition was taken with the enlarged beam. The partition ratio of each element, defined as the ratio of the composition of the carbide to that of the co-existing austenite, became larger in the order of Si, Ni, Mo, Cr and V. The average partition coefficients of Cr, Mo, V, Ni and Si, which are the average eutectic composition at cell tip divided by the composition of the adjacent melt, were about 1.10, 0.51, 1.03, 1.09 and 0.92, respectively. Molybdenum, with the partition coefficient much smaller than 1, segregated remarkably in the eutectic cell. The redistribution of the elements during eutectic growth was numerically analyzed by mass balance and Fick's second law. The calculated results agreed well with the experimental values.抄録全体を表示PDF形式でダウンロード (770K) -
松原 弘美, 西田 義則, 鈴木 鎮夫1979 年 51 巻 11 号 p. 655-659
発行日: 1979/11/25
公開日: 2012/06/02
ジャーナル フリーThe measurement of effective load was carried out for the indirect feeding method of the squeeze casting with aluminum and copper alloys, and load loss was estimated. The load loss increased proportionally with pressure, and decreased as the mold temperature was raised. Small load loss was observed when loading started early, but casting length did not apparently influence the load loss. These results agreed well with the qualitative knowledge which had been acquired empirically. It became apparent that the load loss, which depended upon the kind of alloy, was 30−40% of the hydrostatic pressure and was larger than that of the plunger direct squeeze casting (about 20%). These results suggest the possibility and the limit of the application of the indirect feeding method in squeeze casting.抄録全体を表示PDF形式でダウンロード (632K)
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