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57 巻, 12 号
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研究論文
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洪 鍾徽, 辻川 正人, 池永 明, 川本 信, 岡林 邦夫1985 年 57 巻 12 号 p. 767-772
発行日: 1985/12/25
公開日: 2011/11/17
ジャーナル フリーThe tensile properties of Hard Eye spheroidal graphite cast iron and graphite steel were examined, which are consisted of ferritic matrix and harder second phase surrounding graphite nodules and have excellent wear resistance and toughness. The 0.2% proof stress of ferritic materials was improved about 30% by slightly surrounding the graphite nodules with martensite phase. But, when the sorrounding martensite phase in small fraction was tempered at 600°C for 3h, such improvement was scarcely developed. The stress-strain curve of ferritic graphite steel has low strain hardening coefficient region with e=0.03, and this phenomenon disappeared by surrounding graphite nodules with thin martensite which was obtained by quenching or tempering at 200°C for 1hr. The improvement mechanism of 0.2% proof stress by Hard Eye treatment is explained well by considering constraint factor S which is a function of microstructure.抄録全体を表示PDF形式でダウンロード (684K) -
渕上 正朗, 松尾 勇一, 千々岩 健児, 畑村 洋太郎1985 年 57 巻 12 号 p. 773-777
発行日: 1985/12/25
公開日: 2011/11/17
ジャーナル フリーCharacterization of some usual molding methods, such as jolt, squeeze and air flow-squeeze methods as well as lateral vibration squeeze and pattern squeeze methods developed by the authors was carried out by means of measuring mold hardness using same sand, pattern and flask. And the existence of additive effect was examined when two of these methods are used in combination. For compacting pocket, vertical vibration squeeze jolt-squeeze, air flow-squeeze, lateral vibration squeeze and pattern squeeze are more effective. For compacting locations near flask, pattern squeeze, bottom squeeze and lateral vibration squeeze are more effective. No additive effect was found in combinations of these methods.抄録全体を表示PDF形式でダウンロード (652K) -
堀江 皓, 小錦 利憲, 阿部 喜佐男, 千田 昭夫1985 年 57 巻 12 号 p. 778-783
発行日: 1985/12/25
公開日: 2011/11/17
ジャーナル フリーCast irons containing 3.8%C and 2.2%Si were melted in a graphite crucible using a high frequency induction furnace. At 1,530°C, the nodularization treatment was done by addition of 1.6% of Fe-Si-Mg alloy together with various amount of rare earth element (RE) and calsium using RE-Si and Ca-Si alloys respectively. After the magnesium reaction subsided, the melt was post-inoculated with Fe-Si and was cast to the 3mm thickness plate using CO2 process mold. The formation of chilled structure and graphite nodule count were examined and X-ray microanalysis was carried out to detect RE and Ca in graphite spheroids.
Nodule count was enhanced by the addition of small amount of rare earth element and further increased by the addition of an optimum amount of rare earth element in combination with a small amount of calcium. Some heterogeneous phases with diameter of 1μm or more were observed at the center of graphite spheroids. These phases were composed of spherical rare earth sulfides containing MgO, MgS and CaS. On these phases graphite crystallized in eutectic solidification. It is suggested that rare earth sulfides contribute as the substrate on the formation of graphite spheroids in the thin section cast iron with rare earth element.抄録全体を表示PDF形式でダウンロード (684K) -
新山 英輔, 安斎 浩一1985 年 57 巻 12 号 p. 784-789
発行日: 1985/12/25
公開日: 2011/11/17
ジャーナル フリーSolidification of sand cast steel of some typical shapes was simulated by a finite difference method, assuming that the molds consisted of three kinds of thermally independent parts, i.e. plane mold and molds at external and internal corners. It was found that the assumption of locally independent mold parts leads to error within +2% in the solidification time. Based upon this finding a method of solidification calculation without numerical treatment of the mold was proposed. First, the heat absorption as a function of time characteristic to each localized mold part was determined, assuming an insulated mold except at the casting-mold interface which was kept at a constant temperature. Solidification simulation of steel castings of various shapes was performed using the heat absorption functions determined above as the boundary conditions imposed upon the casting surfaces. It was demonstrated that the computer time is reduced to one third as compared with that of the conventional method of simulation involving numerical treatment of the mold, while increases in the errors of the calculated solidification time are within ±3%.抄録全体を表示PDF形式でダウンロード (637K) -
高柳 猛, 津田 昌利1985 年 57 巻 12 号 p. 790-794
発行日: 1985/12/25
公開日: 2011/11/17
ジャーナル フリーAvailability of α-quartz, α-cristobalite and fused silica to the base refractory for the preformed ceramic core was studied by measuring the sintering characteristics of these materials. The green compacts of each refractory were obtained by injection. In spite of firing at 1,500°C for 1h, the sintering compacts of α-quartz and α-cristobalite were very weak due to poor sinterability and impossible to handle. Only fused silica was well sintered and it prefered to use as the base refractory for the core. The sintered compact of fused silica without crystallization was deformed by softening at high temperature. On the other hand, when almost of fused silica crystallized to cristobalite, the strength of the sintered compact lowered extremely at room temperature. These faults were prevented by controlling the crystallization of fused silica.抄録全体を表示PDF形式でダウンロード (800K) -
徳井 雅昭, 森田 章義, 太田 厚, 鈴木 育夫1985 年 57 巻 12 号 p. 795-800
発行日: 1985/12/25
公開日: 2011/11/17
ジャーナル フリーAluminum alloy specimens cast by vertical pressure diecasting have higher mechanical strength than that in the specimens by conventional pressure diecasting process. In cast specimens produced by vertical pressure diecasting process, which have thick section and machined surface, the lowering of the strength is not serious in comparison with that in the specimens having thin section and as-cast surface. Tensile strength of cast specimens is good correlation with their specific gravity. The coarse primary crystals formed at low casting temperature have an negative influence on the mechanical strength.抄録全体を表示PDF形式でダウンロード (665K)
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