巻号一覧
後続誌
61 巻, 12 号
選択された号の論文の9件中1～9を表示しています
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技術解説
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堤 信久1989 年 61 巻 12 号 p. 852-860
発行日: 1989/12/25
公開日: 2015/01/27
ジャーナル フリーPDF形式でダウンロード (4363K) -
近藤 展啓, 細田 清彦1989 年 61 巻 12 号 p. 861-868
発行日: 1989/12/25
公開日: 2015/01/27
ジャーナル フリーPDF形式でダウンロード (4541K) -
植原 寅藏1989 年 61 巻 12 号 p. 869-875
発行日: 1989/12/25
公開日: 2015/01/27
ジャーナル フリーPDF形式でダウンロード (3509K)
研究論文
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桃野 正, 井川 克也1989 年 61 巻 12 号 p. 895-900
発行日: 1989/12/25
公開日: 2011/08/20
ジャーナル フリーA number of shrinkage predictions in castings have been proposed. In many cases, it has been assumed that the critical values of the parameters for shrinkage are independent of cast structures. In this paper, two-dimentional temperature measurements in aluminum alloy castings were carried out to clarify the effect of cast structures on shrinkage predictions. Temperature gradient (G) distribution and temperature gradient divided by the square root of the cooling rate (G√V) distribution proposed previously applied to these castings at several fraction solid (fS). The area of shrinkage porosities correspond to G = 1.0°C/cm and G/√V = 3.0°C1/2 sec1/2/cm for Al-Cu and Al-Si alloy castings. The shrinkage defect could be estimated from the G/√V in the range of about 0.56 to 0.80 fS. Fraction solid fS depended on the averaged grain size of castings, that is, fS decreased with an increasing the grain size. It is considered that fine crystals may be moved with molten metals by fluid flow during solidification. For a more exact prediction of shrinkage, it may be necessary to take account of the cast structures.抄録全体を表示PDF形式でダウンロード (664K) -
杉本 公利, 田中 浩之, 岡村 正義1989 年 61 巻 12 号 p. 901-905
発行日: 1989/12/25
公開日: 2011/08/20
ジャーナル フリーThe simulation program of inverse V segregation was developed considering floating up of solute enriched liquid during solidification of steel castings. Assumptions adopted in this program were as follows ;
(1) Generation of solute enriched liquid occurs when ε2.1⋅G-1.1 ≦ Climit is satisfied at the area of 30% fraction solid (ε ; cooling rate, G ; temperature gradient).
(2) solute enriched liquid floats up along the solidification front of 30% fraction solid at a uniform rate.
(3) Solute enriched liquid can exist when ε2.1⋅G-1.1 ≦ Climit is effected at the site of floating up.
The result of simulation coincided with the pattern of ghost streaks which were observed on a sulfur print taken from an actual casting. This program has been used to control inverse V segregation and to keep off micro shrinkages at the important portions of castings.抄録全体を表示PDF形式でダウンロード (594K) -
高森 晋, 新山 英輔, 井川 克也1989 年 61 巻 12 号 p. 906-912
発行日: 1989/12/25
公開日: 2011/08/20
ジャーナル フリーDuctile iron melt was poured into dry sand molds to make L-shaped castings. Shrinkage appeared near the internal corner of the casting, depending on the casting thickness and riser neck length.
Two types of solidification simulation were performed. In one type solidification rate was assumed to be a direct function of heat loss. In the other type solidification rate was indirectly related to the rate of heat loss through crystal nucleation and growth, and hence, liquid-solid coexisting zones were modeled.
When using the first type of simulation, predictions based on temperature gradient or modified temperature gradient, considering cooling rate, agreed with shirinkage appearance, provided that the critical values of criteria were suitably selected. When using the second type of simulation, which is considered more realistic than the former, predictions based on the progress of solid fraction in the neck and casting agreed with the experiments, provided that the critical solid fraction for feeding through neck was assumed to be 75%.抄録全体を表示PDF形式でダウンロード (667K) -
陳 適範, 新山 英輔, 大出 卓, 井川 克也1989 年 61 巻 12 号 p. 913-918
発行日: 1989/12/25
公開日: 2011/08/20
ジャーナル フリーAl-Cu alloys with various compositions were solidified unidirectionally. The observed porosities were classified into five types with respect to the aspect ratio and other geometric characteristics. The largest quantity of porosities are formed in a condition which favors the growth of long secondary dendrite arms. Primary and secondary arm spacing, eutectic area ratio, and tortuosity of the feeding paths were measured by image analysis of the solidification structure. Using a simple physical model, the observed amount of porosity ratio was qualitatively related to a parameter combining the above factors and hydrogen content.抄録全体を表示PDF形式でダウンロード (748K) -
品田 与志栄, 上田 俶完, 滝 顕治1989 年 61 巻 12 号 p. 920-925
発行日: 1989/12/25
公開日: 2011/08/20
ジャーナル フリーThe gases in biscuit, runner, gate, product and overflow portions of aluminum alloy die castings were investigated by mass spectrograph. The gas content was the lowest in the biscuit, and gradually increased in the runner and gate, and abruptly in the product and overflow. The gas of the biscuit contained about 80% hydrogen and 20% nitrogen, but the content ratio of hydrogen to nitrogen in the product portion was reversed, because the molten metal injected through a gate included large amounts of air from die cavity. The gas content and porosity varied from position to position in the product and was the highest in the position near the gate which included more nitrogen than hydrogen.抄録全体を表示PDF形式でダウンロード (644K) -
品田 与志栄, 上田 俶完, 滝 顕治1989 年 61 巻 12 号 p. 926-931
発行日: 1989/12/25
公開日: 2011/08/20
ジャーナル フリーIt was revealed by mass spectrograph that gas defects were caused by nitrogen and hydrogen in aluminum alloy die castings. The amount of nitrogen included by molten metal was varied by some mechanical factors of die casting conditions. When the plunger speed was turned to fast after passing of molten metal through the gate and entering into the die cavity, the amount of nitrogen and the gas porosity in the product portions were significantly decreased. On the other hand, the amount of hydrogen was influenced by some chemical factors of die casting conditions. The use of much moldwash increased the amount of hydrogen and the gas porosity, but the hydrogen absorption and the porosity formation were prevented after blowing of the excessive lubricant.抄録全体を表示PDF形式でダウンロード (640K)
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