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41 巻, 6 号
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研究論文
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山下 昭夫1969 年 41 巻 6 号 p. 415-422
発行日: 1969/06/25
公開日: 2012/10/03
ジャーナル フリーTo make a permanent sand mold usable for repeated usage, a study has been carried out on a sand mold bonded with aluminium phosphate and magnesium oxide. The mold thus prepared was durable enough to be used more than 20 times, its compression strength being above 10 kg/cm2. The rate of hardening could be controlled by varying the amount of adding magnesium oxide to the mold. Various sands such as olivine sand, chromite sand and zircon sand were employed, but irrespective of the kind of sand the compression strength was not lowered after a heating repetition of 20 times. Further it was found that the repetition of heating had no influence upon the surface condition of thd permanent mold. When the mold was heated, the compression strength was maintained constant up to 800°C but decreased at higher temperatures, espesially because of softening of bonding material above 1,000°C.抄録全体を表示PDF形式でダウンロード (801K) -
鈴木 松夫, 松居 菊千代, 杉浦 泰夫, 落合 修二1969 年 41 巻 6 号 p. 422-434
発行日: 1969/06/25
公開日: 2012/10/03
ジャーナル フリーThe effect of cobalt addition on the grain refining of copper beryllium alloy for castings was studied. For this the liquidus part of Cu-Be-Co phase diagram was investigated to clarify the range in which grain size of the alloy was refined by adjusting the ratio of beryllium to cobalt, by using thermal analysis, microscopic and X-ray microanalytic observation. Experimental results were : 1) The grain refining of the alloys was caused due to the peritecto-eutectic reaction of Cu-Be-Co ternary alloys. There were found five primary crystals including Cu-, Co-, β-, BeCo- and X-phase in that range of alloys investigated. 2) In the copper rich part of the ternary alloy diagram there were two eutectic lines on which coarse grains were produced. One consisted of liquid, alpha Co and BeCo, the other consisting of liquid, BeCo and X-phase. The former started from a point of Be1%, Co1.6% and the rest Cu, while the other started from a point of Be4.3%, Co1.7% and the rest Cu. 3) There took place two non-variant reactions, one of which is given by Liquid+(Co)⇌(Cu)+BeCo, and the other is shown by Liquid+X-phase⇌β-phase+BeCo. The former occurred at about 1,031°C and a chemical composition of Be1%, Co1.6% and the rest Cu, the latter occurring at about 866°C and composition of Be4.3%, Co1.6% and the rest Cu. 4) The range of chemical composition in which fine grains were produced can be shown by F1 and F2 in the phase diagram in Fig. 21.抄録全体を表示PDF形式でダウンロード (1445K) -
川崎 獺雄1969 年 41 巻 6 号 p. 434-440
発行日: 1969/06/25
公開日: 2012/10/03
ジャーナル フリーThe change in the microstructure of hyper-eutectic Al-Si alloys containing silicon of 20%, which was made by adding phosphorous was studied by means of optical microscope, electron microscope and X-ray microanalyser. Fxperimental results were : 1) Addition of phosphorous to hyper-eutectic Al-Si alloys resulted in remarkable refinement of primary silicon crystals. 2) In the center of silicon crystal there existed a nucleus of grey color, having a shape similar to that of the silicon crystals. 3) X-ray microanalyzer showed that the nucleus was a compound of Al-P. 4) The effect of phosphorous addition made at 800°C was promoted by adding the other elements which had a tendency to retard the growth of primary silcon crystals.抄録全体を表示PDF形式でダウンロード (1117K) -
百瀬 敬吾, 地引 和光, 山本 郁夫, 岡林 邦夫1969 年 41 巻 6 号 p. 440-450
発行日: 1969/06/25
公開日: 2012/10/03
ジャーナル フリーHeat insulating property of refractory coating on metal mold is improved by adding transition metal phosphates such as Cr, Co or Cu phosphate. In the present paper the effect of such phoshates upon metal mold castings was tested by measuring temperature changes in both casting and metal mold and inspecting microstructure of the castings. The results obtained were : 1) Chromium phosphate had the most favourable effect on the insulating property of coating when chromium phosphate of 0.02 mol was added to a bonding material of 100 g. Cobalt phosphate was the better second and copper phosphate the third in turn. 2) The cooling rate of castings during solidification could be measured by using a sensitive pyrometer. As a result of measurement it was known that there was a clear relationship between the cooling rate and chilling effect of castings. 3) Diatom earth and silica flour showed an excellent insulating property for mold coating, while graphite showed very poor insulating property. As a bonding material aluminium phosphate was superior to sodium silicate. 4) Eutectic graphite structure was formed near the surface of castings. The thickness of the layer having eutectic graphite structure increased with increasing the rate of cooling.抄録全体を表示PDF形式でダウンロード (1078K) -
神尾 彰彦, 雄谷 重夫1969 年 41 巻 6 号 p. 450-460
発行日: 1969/06/25
公開日: 2012/10/03
ジャーナル フリーTo investigate the influence of vibration on solidifying hypo-monotectic copper-lead alloy casting was made in a mold vibrating at 910 cycles per second. In case of 20% lead-copper alloy vibration caused a grain refinement. The refinement of grains was considerably influenced by the length of vibration period during solidification. The longer the length of vibration period, the finer the grain size became parabolically. Therefore, it was desirable for grain refining that vibration was applied to casting during the whole nucleation period from liquid state to about 15°C below the liquidus line. No grain refinement occurred when vibration was applied at 20°C below the liquidus. When vibration was applied to liquid metal, undercooling did not take place during solidification. Primary crystals of alpha solid phase were deformed or broken in the beginning of solidification and so there was found no dendritic morphorogy. Further, segregation or leakage of lead in the upper part of casting could be eliminated when vibration was applied from liquid state up to the end of monotectic reaction.抄録全体を表示PDF形式でダウンロード (1499K)
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