巻号一覧
後続誌
56 巻, 12 号
選択された号の論文の6件中1～6を表示しています
- |<
- <
- 1
- >
- >|
研究論文
-
広本 照夫, 岡村 和雄, 冨井 洋一, 水野 政夫1984 年 56 巻 12 号 p. 727-733
発行日: 1984/12/25
公開日: 2011/11/26
ジャーナル フリーTo investigate how hot cracking occurs during welding, arc spot testing and MIG welding were conducted on cast copper plates produced under different deoxidizing conditions for improving weldability. Hot cracked surfaces were examined analytically by scanning electron microscopy. Much more cracks formed in the cast copper plates deoxidized by P than in the plates deoxidized by Si. Hot cracks occured at the grain boundary and the characteristics of liquation cracking were observed on cracked surfaces. Substances having low melting points were likely to be formed at the grain boundary which may be a result of excess deoxidizer, P, or complex reaction products, CuO-P2O5, after deoxidation. Although hot cracks formed rarely in cast copper plates deoxidized by Si, castability was not so good with respect to fluidity during casting.抄録全体を表示PDF形式でダウンロード (902K) -
小室 勝博, 諏訪 正輝1984 年 56 巻 12 号 p. 734-739
発行日: 1984/12/25
公開日: 2011/11/26
ジャーナル フリーThe wear resistance of several Al- and Cu-base alloys containing graphite particles up to 20 vol% has been investigated to select the most appropriate matrix for graphite dispersed casting alloys. Alloys with uniformly dispersed graphite particles were obtained. Ni-coating graphite particles were added to the Al-base alloy melts, while Cu-coated ones were added to the Cu-base alloy melts. After finishing the pouring, high pressure of 600kgf/cm2 was applied to the melts from the mold's upper side direction. The wear resistance test was made under dry condition.
In a series of Al-base alloys, the specific wear of the Al-Cu and Al-Sn alloys remains constant in the matrices containing graphite particles up to 10 vol% and then begins to decrease when their volume fraction exceeds 10 vol%. The specific wear of the Al-Cu and Al-Sn alloys containing 20 vol% graphite particles is about 10−6mm3/mm·kg. The apecific wear of the Al-Si alloys decreases with increasing the volume fraction of graphite particles, reaching about 10−7 mm3/mm·kg when the 20 vol% graphite particles is added. In Cu-base alloys, the specific wear of the Cu-Al, Cu-Zn and Cu-Sn alloys tends to decrease with increaing the volume fraction of graphite particles. The specific wear of the former two alloys falls in the range between 10−7 and 10−6mm3/mm·kg, while the latter one is in the range between 8×10−9 and 10−8 mm3/mm·kg.抄録全体を表示PDF形式でダウンロード (741K) -
近藤 康雄, 福迫 達一1984 年 56 巻 12 号 p. 740-745
発行日: 1984/12/25
公開日: 2011/11/26
ジャーナル フリーUsing some gating systems, distribution of water flow in multiple ingate systems was simulated by water model, and then compared with calculated results which was obtained from Bernoulli's law. The water distribution ratio was affected by shape and position of ingates and length of runner. These phenomena are controlled by Bernoulli's law to some extent. But neither the hydraulic pressure of water which is flowing through the runner nor agitation flow can be described by Bernoulli's equation. Moreover, when the sectional area of runner is larger than that of the sprue, in the early stage of the pouring operation, flow rate through the runner is determined by friction factor at the junction of pouring basin and sprue. And as water fills the runner, water flow in gating system transforms into a steady flow which is predicted by Bernoulli's law.抄録全体を表示PDF形式でダウンロード (597K) -
村上 信義, 小林 俊雄, 大和田野 利郎1984 年 56 巻 12 号 p. 746-751
発行日: 1984/12/25
公開日: 2011/11/26
ジャーナル フリーAustenitizing and quench-hardening of ferritic spheroidal graphite cast iron were measured quantitatively by dipping small specimens in molten aluminum bath for various length of time followed by water quenching. The austenitizing proceeded somewhat before the specimen attained the bath temperature, but mostly thereafter. The higher the bath temperature, the shorter was the time for complete austenitizing. And the more rapid the heating rate, the faster was the austenitizing in early stage at a given bath temperature. However, the time for complete austenitizing was almost independent of the heating rate and inversely proportional to the graphite nodule count. The austenitizing curves on rapid heating were derived considering the temperature at a given time to be constant during a very short interval of time. And an approximating equation available for estimating the time for complete austenitizing was also derived. These equations were in good accord with the corresponding experimental data. The time for complete quench-hardening was found to be about five times as long as the time for complete austenitizing at the same bath temperature.抄録全体を表示PDF形式でダウンロード (638K) -
林 克光, 藤原 幹男, 田中 雄一1984 年 56 巻 12 号 p. 752-757
発行日: 1984/12/25
公開日: 2011/11/26
ジャーナル フリーSolidification process of CV graphite iron was investigated with addition of various CV-graphitizing materials to the cast iron and the crystallization behavior of the graphite during the eutectic reaction was clarified. The two arrest regions on the cooling curve during eutectic freezing were observed in the cast iron with CV graphite. At the first stage of the arrest, the spheroidal graphite nucleating prior to the eutectic freezing grew with austenite shell. CV graphite was formed at the second stage and grew in contact with the liquid due to partial dissolution of the austenite shell surrounding the graphite spheroid. Accordingly, it was suggested that the graphite nodule formed in the first stage of eutectic freezing served as the starting point of CV graphite growth.抄録全体を表示PDF形式でダウンロード (881K) -
洪 俊杓, 梅田 高照, 木村 康夫1984 年 56 巻 12 号 p. 758-764
発行日: 1984/12/25
公開日: 2011/11/26
ジャーナル フリーPrediction of shrinkage cavity formation in shaped castings by the boundary element method was demonstrated with several examples. The five prediction parameters, i. e. (1) solidification time, ts, (2) critical fraction solid for fluid flow, fs_critical, (3) temperature gradient, G, (4) fraction solid gradient, fs_G, and (5) G/√R, were analyzed. A new parameter, “shrinkage potential,” which includes amount of shrinkage cavity and porosity was proposed as a auxiliary parameter, for analyzing shrinkage cavity quantitatively. Since the amount of shrinkage cavity is mainly related to volume contraction during solidification of molten metals in casting processes, the shrinkage potential does not depend on the size or shape of the castings. By the use of this new parameter, the critical values of prediction parameters which depend on the size or shape of the castings can be determined automatically by computer simulation. It was found that solidification time mainly predicts the formation of shrinkage cavity around the region of the final solidification point ; and temperature gradient, fraction solid gradient and G/√R mainly predict the formation of internal porosities. Therefore, combined use of the prediction parameters, ts and G, and a auxiliary parameter, shrinkage potential, is necessary for predicting the formation of all types of shrinkage defects in shaped castings.抄録全体を表示PDF形式でダウンロード (721K)
- |<
- <
- 1
- >
- >|