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46 巻, 11 号
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研究論文
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山田 始, 田中 他喜男1974 年 46 巻 11 号 p. 955-961
発行日: 1974/11/25
公開日: 2012/09/20
ジャーナル フリーThis study was carried out to examine the machinability of spheroidal graphite cast iron by high speed and super-high speed machining at 1,000 m/min degree under the following conditions; depth of cut, 0.5 mm; feed, 0.05 mm/rev; tool, sintered hard metal or ceramic.
The cutting resistance in the super-high speed machining of spheroidal graphite cast iron considerably decreased because the decrease of cutting resistance with increased cutting speed was considerable in case of the spheroidal graphite cast iron although it was small in the case of negative rake angle such as −5°. Also flank adhesion phenomenon disappeared under this cutting speed. Flank adhesion phenomenon occured under cutting speed of 300-600 m/min when using sintered hard metal tool. It was considered that adhesion in spheroidal graphite cast iron is caused by the coexistence of ferrite and graphite, which graphite produces very fine chips during machining.
The life of sintered hard metal tool was very short in super-high speed machining, while that of the ceramic tool was much longer than that of the sintered hard metal tool, though its life was inferior compared to the case of grey cast iron machining. Flank adhesion did not occur with the ceramic tool. Finished surface improved with the super-high speed machining, though the case of the ceramic tool was inferior to the case of the sintered hard metal tool.抄録全体を表示PDF形式でダウンロード (1058K) -
大出 卓, 大平 五郎1974 年 46 巻 11 号 p. 962-967
発行日: 1974/11/25
公開日: 2012/09/20
ジャーナル フリーIt has been known that a thin surface layer (casting skin) is formed on the surface structure of grey cast iron castings. This surface layer is said to consist of a reaction zone where the metal has reacted chemically with the mold materials and the gasses in the mold and a transition zone which formed because of the cooling condition of the mold. There is no precipitated graphite in this layer so that is offers greater resistance to machining. The formation of the layer is influenced by various factors such as the composition of cast iron, casting temperature, cooling rate, molding materials, mold dressing, innoculation and so on. Though it is difficult to describe sufficiently the effect of these factors on the formation of the layer, the main purpose of this study is to examine how it is formed.
In this investigation, five kinds of raw iron materials were used; ductile iron (A) and (B), charcoal iron, low phosphorus iron and electrolytic iron. Under constant molding and casting conditions, the iron of a standard composition (3.5%C-2.0%Si) was cast into a unified green sand mold. The effect of heredity of the raw iron materials, solidification characteristics, innoculation and alloying elements (Mn, P, S) on the formation of the layer were examined. The results obtained were that the formation of the surface layer of the grey iron castings depended not only on the decarburization of the metal-mold chemical reaction which was already reported, but also on the solidification characteristics of the molten metals.抄録全体を表示PDF形式でダウンロード (896K) -
西 成基, 篠田 武雄, 鈴木 寛志1974 年 46 巻 11 号 p. 968-974
発行日: 1974/11/25
公開日: 2012/09/20
ジャーナル フリーThe influences of Si, Mg and Zn on the mechanical properties and fluidity of Al-4.5%Cu alloy was investigated. The cast alloys were solution heat-treated at 515°C for 10 hrs and tempered 160 °C for 8 hrs.
The addition of Si to Al-4.5%Cu-0.25%Ti alloy lowered the tensile strength somewhat and increased elongation. The addition of Mg to Al-4.5%Cu-0.25%Ti alloy made the tensile strength higher and the elongation smaller than those of Al-4.5%Cu-1.0%Si-0.25%Ti alloy. The addition of both Si and Mg to the Al-4.5Cu-0.25%Ti alloy made the tensile strength higher and the elongation smaller than those of Al-4.5%Cu-0.3%Mg-0.25%Ti alloy. The addition of 1-3%Zn to Al-Cu-Si-Ti alloys improved the tensile strength remarkably. However, these alloys containing 4%Zn were susceptible to burning so that the solution heat treatment temperatures had to be lowered.
It was found in these alloys that the more the silicon was added, the more the shrinkage cavity in the feeder decreased, and titanium reduced the contraction of the feeder remarkably, The length of fluidity was extended more in Al-Cu alloys with silicon or magnesium addition. When a small amount of titanium was added to Al-Cu-Si, Al-Cu-Mg and Al-Cu-Mg alloys, the sensibility to temperature on the fluidity became smaller and the fluidity of those alloys became better.抄録全体を表示PDF形式でダウンロード (742K) -
喜多 清, 清重 正典, 中村 敬和1974 年 46 巻 11 号 p. 975-980
発行日: 1974/11/25
公開日: 2012/09/20
ジャーナル フリーThough the ultimate strength and the proof stress of austenitic stainless steel increased by lowering the temperature, the tensile ductility and the toughness were reduced. However, the steels containing a small amount of ferrite still had a relatively high toughness at a temperature as low as −196°C. Scanning microscope examination of the broken tensile and impact test pieces showed that a quasi-cleavage type of fracture appeared at lower tempratures. It is considered that the quasicleavage type fracture is related to the area of ferrite and the stability of the austenite.抄録全体を表示PDF形式でダウンロード (1007K) -
岡倉 常之, 久保田 博1974 年 46 巻 11 号 p. 981-987
発行日: 1974/11/25
公開日: 2012/09/20
ジャーナル フリーIt has been found that mold damages and swelling which occur in low pressure squeeze molding can be prevented by adding an excess of clay substance to the sand mixture. It the amount of clay substance can be decreased by means of high pressure molding, a denser and more uniform mold can be gained and the above mentioned mold defects can be prevented. This report is concerned with the method of determining the optimum moisture content of green sand mixtures for high pressure molding to minimize the clay content and stabilize the compaction properties, sand grain density, uniformity of grain density and permeability.
The optimum moisture content for minimizing the clay content and stabilizing the compaction properties was obtained when the moisture/bentonite content ratio was about 3/7. Further, it was found to be important to choose the bentonite that showed the highest green tensile strength at the above ratio. The scattering of values of compaction properties and the spring-back property, owing to the changes in moisture and bentonite content, was minimized when the ratio of moisture/bentonite content was approximately 3/7.抄録全体を表示PDF形式でダウンロード (657K) -
中野 耕作, 雄谷 重夫1974 年 46 巻 11 号 p. 988-992
発行日: 1974/11/25
公開日: 2012/09/20
ジャーナル フリーIt was already predicted in the preceeding papers by the present authors that the factors governing inverse segregation in the Cu-Sn alloy were the interdendritic flow of solute-rich liquid and the solute concentration in the liquid which depend on the dendrite morphology. This paper describes the dependence of dendrite morphology on inverse segregation. The Cu-8%Sn alloys containing small amounts of Al, Si, P, Ni or Fe to alter dendrite morphology were solidified unidirectionally or free-directionally under controlled conditions.
The alloys containing Al and Si have elongated arms of primary dendrites, while ones containing Ni and Fe have shortened arms. The inverse segregation is accelerated in the former and relieved in the latter. The inverse segregation strongly depends on the dendrite morphology.抄録全体を表示PDF形式でダウンロード (764K) -
加藤 栄一, 太田 久司, 鵜飼 直道1974 年 46 巻 11 号 p. 993-999
発行日: 1974/11/25
公開日: 2012/09/20
ジャーナル フリーThe equilibrium data in the reaction
H2O(g)=H2(g)+O(in liquid copper)
are very important for foundry practice of copper casting. Allen and Hewitt determined this equilibrium about fourty years ago, but the importance of this equilibrium is such that redetermination would be useful. In this study, the equilibrium constant has been obtained at the temperature of 1,150°C, 1,250°C and 1,350°C, and at a water vapour pressure of 92.5mmHg. A sample of about 150g in weight was heated by high frequency induction heating and the developing hydrogen pressure was measured by diffusing hydrogen into an evacuated palladium tube. The oxygen in samples was determined by the vacuum fusion technique.
The equilibrium constant for the reaction is expressed as :
log K0=log(PH2·a0⁄(PH2O))=−8594⁄T +1.956
This value is quite different from that obtained by Allen and Hewitt, but is in good agreement with the values calculated from the experimental results obtained by the electrochemical determination of oxygen in liquid copper or by the equilibrium measurements of the reaction of carbondioxide with liquid copper.抄録全体を表示PDF形式でダウンロード (683K)
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