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62 巻, 2 号
選択された号の論文の8件中1～8を表示しています
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研究論文
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安斎 浩一, 内田 敏夫1990 年 62 巻 2 号 p. 90-95
発行日: 1990/02/25
公開日: 2011/07/27
ジャーナル フリーA mold filling simulation method for die casting is proposed. New type cell named FS Cell is employed to improve the accuracy of mold filling simulation by Simplified Marker And Cell (SMAC) method. The FS cell has a free surface paralleled to two dimensional (X-Y) plane.
Exsistence of the free surface is considered by fluid filling ratio of the mesh used by SMAC Method.
Pressure is assumed to be constant in the FS cell and the fluid filling ratio is determined to satisfy mass conservation equation after determining the velocity of the FS cell by momentum equations.
Availability of quasi three dimensional model to die casting problem is examined and some applications of the extended SMAC method are described.抄録全体を表示PDF形式でダウンロード (798K) -
朱 金東, 大中 逸雄1990 年 62 巻 2 号 p. 96-100
発行日: 1990/02/25
公開日: 2011/07/27
ジャーナル フリーAl-4.5 mass % Cu alloy ingots were solidified under high atmospheric pressures upto 4MPa. The effect of total atmospheric pressure, initial hydrogen content and cooling rate on porosity were examined and discussed by comparing the experimental results with computer simulation. Both the simulation and experimental results showed that the amount of porosity decreased with increasing total atmospheric pressure, decreasing initial hydrogen content and increasing cooling rate. Porosity was almost completely suppressed above 2MPa. Further, it was found that the decrease in porosity is mainly caused by the increase in internal pressure of pores and the effect of the increase in hydrogen solubility is small.抄録全体を表示PDF形式でダウンロード (718K) -
青山 正治, 松尾 國彦, 小林 俊郎1990 年 62 巻 2 号 p. 101-106
発行日: 1990/02/25
公開日: 2011/07/27
ジャーナル フリーIn this study, effects of silicon content and austenitizing condition on the impact characteristics of austempered ductile cast iron were investigated by special austempering treatment. The cast iron was alloyed in three levels of Si content of ranging from 1.5 to 3.5wt% with or without Ni and Mn.
The optimum condition of the heat treatment for improving the impact properties was to prequench once from the austenite region in order to refine the prestructure and then to austemper from near the Af (austenitizing finishing temperature) range. It was ascertained that refined mixed structure of ferrite and bainite were formed in the final state by this special treatment.
The proper content of Si was also found. The sample containing 2.1wt%Si showed a good conbination of strength and toughness. Although the unalloyed cast iron showed a good impact value, dynamic fracture toughness value was lowered probably due to its poor strength.抄録全体を表示PDF形式でダウンロード (907K) -
藤田 武男, 大城 桂作, 福井 昻, 末永 允1990 年 62 巻 2 号 p. 107-111
発行日: 1990/02/25
公開日: 2011/07/27
ジャーナル フリーThe rolling contact fatigue strength of spheroidal graphite cast iron which was austempered at 375°C and 235°C for 2hr was investigated by using a Nishihara-type wear machine under a light oil lubricant, and the results were compared with those of quenched and tempered spheroidal graphite cast iron and steel. The rolling contact fatigue limit (F*) of steels and cast irons became larger as their hardness increased. At the same hardness level, F* of austempered cast Irons were much higher than those of quenched and tempered cast irons. Moreover, the austenitic-bainitic cast iron was superior to qenched and tempered steels.抄録全体を表示PDF形式でダウンロード (730K) -
片島 三朗, 田島 俊造, 楊 栄顕, 近藤 孝幸, 九十九 一貫1990 年 62 巻 2 号 p. 112-116
発行日: 1990/02/25
公開日: 2011/07/27
ジャーナル フリーThe experiment is regarded as a fundamental of a gas defect's countermeasure on the Evaporative Pattern Casting Process. Observations of the fluidity, the formation of a molten metal skin and the substitutional state of the EPS pattern-molten silumin were performed by adopting a new method.
The results in this experiment are as follows:
1. By this new method, immediately after pouring, a suitable volume of water was poured into the mold in order to chill the mold. As a consequence, this method of observing the substitution between the EPS pattern and the molten silumin becomes a possible method.
2. At the boundary of the pattern and mold, the space made by the molten silumin where the EPS pattern is heated quickly, is not filled by the molten silumin, but almost flows by contact on the molten silumin.
3. The molten metal flows through the boundary of the pattern and molds firstly, and then wraps the EPS pattern, and finally fills the internal portion of the mold. So it is thought to be the usual cause of gas defects.
4. At the boundaries of the EPS pattern and the mold, the flow velocity of the molten metal is deeply affected by the vacuum degree; i. e., the higher the vacuum degree, the faster the flow velocity.抄録全体を表示PDF形式でダウンロード (714K) -
斎藤 和夫, 川口 健美, 鵜飼 利昌1990 年 62 巻 2 号 p. 117-123
発行日: 1990/02/25
公開日: 2011/07/27
ジャーナル フリーThis study is intend to improve and extend the life of refractory brick used in the melting zone which is the most critical zone for long campaign operation of a small size cupola. To determine the wear mechanism of the refractory brick used in the melting zone, several laboratory tests and actual cupola lining tests were performed to compare various different refractory brick designs.
It was found, as a result of those tests, that the refractory brick used in the melting zone needs thermal resistance under extremely high temperatures as well as balanced erosion and corrosion resistance against slag and molten pig iron. A SiC bonded SiC-Al2O3 brick which was designed and produced to provide such properties was actually tested in the melting zone of a small size cupola. The brick showed the same durability as high purity SiC brick.抄録全体を表示PDF形式でダウンロード (847K) -
永井 恭一, 岸武 勝彦1990 年 62 巻 2 号 p. 124-129
発行日: 1990/02/25
公開日: 2011/07/27
ジャーナル フリーImpact characteristics have been investigated in ferritized spheroidal graphite cast iron varying both graphite nodule size and ferrite grain size in order to clarify these effects independently. The results are summarized as follows:
(1) Impact value of the specimen of coarse graphite nodules is higher than that of fine graphite nodules in the temperature range of ductile fracture, while the effect of graphite nodule size on maximum load for impact fracture is reverse.
(2) Upper-shelf impact value is influenced primarily by the graphite nodule size and less affected by the ferrite grain size.
(3) Transition temperature of impact value is lowered by refining the graphite nodule size as well as the ferrite grain size.
(4) Upper-shelf impact value of the specimen containing secondary precipitated fine graphites is lower than that of a normally ferritized iron. The transition temperature of impact value is shifted to a lower temperature by the secondary graphite precipitation. This is the same behavior as the refinement of graphite nodule size.抄録全体を表示PDF形式でダウンロード (789K) -
佟 慶平, 鈴木 俊夫, 梅田 高照1990 年 62 巻 2 号 p. 130-137
発行日: 1990/02/25
公開日: 2011/07/27
ジャーナル フリーThe influence of chemical composition was investigated on the eutectic solidification and the structure of high chromium cast irons with various carbon (2∼3.5%) content and chromium (7∼20%) content, to which silicon, nickel, molybdenum and vanadium were added as alloy elements.
Liquidus temperature (Tl), (γ + M7C3) eutectic temperature (Te) and solidification finishing temperature (Tf) depend mainly on the carbon content.
The larger the carbon content, the lower the Tl, Te and Tf. On the other hand, for the alloy with a constant carbon content, (γ + M7C3) eutectic temperature (Te) and solidification finishing temperature (Tf) increase, however, liquidus temperature (Tl) remains almost unchanged with increase of chromium content.
Two kinds of eutectic carbides (M7C3 and M3C) appear in 7%Cr cast irons with more than 2%C and also in 10%Cr cast irons with more than 3%C. The monovariant (γ + M3C) eutectic solidification starts at 1157°C. (γ + Mo2C) eutectic structure was identified in all cast irons with 1%Mo or more. Amount of eutectic carbides is determined by the contents of carbon and chromium.抄録全体を表示PDF形式でダウンロード (941K)
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