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55 巻, 3 号
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研究論文
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遠藤 隆1983 年 55 巻 3 号 p. 137-142
発行日: 1983/03/25
公開日: 2011/12/13
ジャーナル フリーThe wear resistance of ion-nitrided flake graphite cast iron test pieces was measured under dry sliding condition (100% sliding) by use of Ōgoshi-type wear testing machine. The solbitic structure JIS SK 5 and flake graphite cast iron were used as sliding materials. (1) On the ion-nitrided surface layers ε-Fe2∼3N, γ1-Fe4N and α-Fe were observed by X-ray diffraction. The surface hardness was about Hv 1,250 under ion-nitrided atmosphere of 60%N2 and 40%H2 (IN) and about Hv 1,050 under ion-nitrided atmosphele of 30%N2, and 70%H2 (INL). The depth of the hardened surface was about 0.30-0.35 mm estimated from the hardness distribution curves. On the other hand, the surface hardness of the soft-nitrided treatment was about HV 700 ∼ 1,000. (2) In the ion-nitrided cast iron combined with SK 5, good wear properties were obtained at 3.2 kg and 6.3 kg of final contact pressures. But, it was found that the wearing loss was largest at 12.6 kg final contact pressure. (3) In relation to the sliding velocity and the wearing loss, wearing loss was smallest when the ion-nitrided iron (IN) and untreated flake graphite cast iron were combined. (4) Ion-nitrided treatment improved the wear resistance, and in comparison with untreated flake graphite cast iron, the wear resistance value of the ion-nitrided cast iron in the mechanical wearing range were higher by 102 ∼ 103 (5) In the oxidation wearing range, wearing loss was smallest in the soft-nitrided iron followed by ion-nitrided (IN) and ion-nitrided (INL) iron, and it was greatest in the untreated cast iron.抄録全体を表示PDF形式でダウンロード (766K) -
上田 俶完, 森 正平, 谷 耕治1983 年 55 巻 3 号 p. 143-148
発行日: 1983/03/25
公開日: 2011/12/13
ジャーナル フリーFe-25%Cr-12%Ni cast steels and Co-base alloy were oxidized by linearly increasing temperature and by isothermal heating at different temperatures in air, and tested by thermobalance and EPMA. Approximate temperature ranges, in which the alloy can be used, were found by linearly increasing temperature in a single try at oxidation. Using the result obtained, available temperature limit could be defined and a comparison of oxidation resistance could be made by a few isothermal oxidation tests. Addition of rare earth metals (0.2%and 1.0%) reduced the oxidation rate of the cast steel below 1,100°C, but caused catastrophic oxidation above 1,200°C. On the other hand, Co-base alloy behaved in a similar manner with the rare earth-free cast steel, but was superior in heat-resisting property. The oxidation resistance of the Co-base alloy was superior to that of the rare earth-containing cast steel at 1,200°C, but was inferior below 1,100°C.抄録全体を表示PDF形式でダウンロード (837K) -
田中 雄一, 藤原 幹男1983 年 55 巻 3 号 p. 149-155
発行日: 1983/03/25
公開日: 2011/12/13
ジャーナル フリーThe pearlite promoting effects of small additions of Sb are evaluated for compacted/vermicular graphite iron castings with 0.6%Ni and 0.9%Cu at two Si levels. Microstructural results for various section sizes of stepped pattern indicate that the level of Sb needed to ensure a nearly fully pearlitic matrix structure is dependent on the Si contents of the iron and the amount of pearlite is relatively insensitive to the section thickness, i.e., 0.057%Sb for lower Si contents iron and 0.1%Sb for high Si contents are required. By the additions of Sb, it is also observed that the graphite begins to modify from compacted graphite which is short and stubby in shape with a rounded edge, to the degenerated graphite which is slightly thinner with needle-like projections. Therefore, the numerical index, i.e., the mean shape factor of graphite K, decreases from 0.57 to 0.40 for 20 mm sections with Sb content. Also, the ultimate tensile strength and elongation of the irons decrease with the same tendency with the change in K value. The neutralizing effects of additions of Ce are investigated for the iron castings with the pearlitic matrix by addition of Sb. Increasing Ce results in the disappearance of degenerated graphite such as those with needle-like projections and thinner ones with sharp edges and in the increase of the K value. By combination of Sb and Ce, the matrix structures become essentialy fully pearlitic and significantly increases hardness and tensile strength.抄録全体を表示PDF形式でダウンロード (743K) -
李 鏞河, 金 豊, 原 邦夫, 沢本 崇, 井ノ山 直哉, 川野 豊1983 年 55 巻 3 号 p. 156-163
発行日: 1983/03/25
公開日: 2011/12/13
ジャーナル フリーUsing metal mold dressed with acetylene black, the change in chilling tendency of spheroidal graphite cast iron due to melting condition and addition of some elements was investigated and some factors affecting the spheroidization of graphites were also studied. It was found that melting conditions such as holding over a long period of time or at a high temperature before the spheroidizing treatment cause spheroidal graphite cast iron as well as flake graphite cast iron to chill. In order to clarify the effect of melting conditions on the chill, cast irons were melted in a high frequency vacuum furnace. Iron melts were thereafter held under either N2 (0.8 atm) or O2 (0.2 atm). It was found that in holding melts under vacuum, chill was markedly reduced, however in holding under atmosphere of N2 or O2, chill increased again remarkably. These results indicate that the effect of N and O on the chilling of cast irons are very important. Chilling tendency of the melt from which N and O were removed by addition of Al and Ca before spheroidizing treatment, was then examined. As a result, spheroidal graphite cast iron structures free from ledeburite cementite were obtained in samples of 20 mm diameter bar containing 3.4∼3.8%C, 3.5∼4.3%Si and 0.015∼0.02%Mg.抄録全体を表示PDF形式でダウンロード (932K) -
大中 逸雄, 近藤 康雄, 福迫 達一1983 年 55 巻 3 号 p. 164-170
発行日: 1983/03/25
公開日: 2011/12/13
ジャーナル フリーA numerical method to analyze quasi-steady flow phenomena in various complex gating systems by just changing the input data for the computer is proposed. The input data in this method is produced by dividing the gating system into elements which have nodal points on edges like the finite element method. In a computer, the equation of continuity at nodal points and the energy equations (Bernoulli's equation) between the melt surfaces in the spure and cavities are constructed automatically using the linear graph theory and solved numerically by an iterative method. Results of some computations have been compared with water model experiments. This shows that the flow rate at gates and fill time of cavities can be estimated within about 10 percent error. The proposed method appears to be useful for designing practical complex gating systems.抄録全体を表示PDF形式でダウンロード (707K) -
大城 桂作, 金子 国伸, 松原 安宏, 伊里 昭寛, 松田 公扶1983 年 55 巻 3 号 p. 171-177
発行日: 1983/03/25
公開日: 2011/12/13
ジャーナル フリーTorsion tests in the range of room temperature to 600°C were carried out in high chromium cast irons containing 5%, 15% and 30%Cr with varying eutectic ratio from 20% to 100%. In each specimen, the maximum shearing stress (τmax) as a strength did not change very much with the temperature up to 400°C and decreased considerably at 600°C. τmax of as-cast specimen was generally higher than that of the annealed specimen. Absorbed energy to fracture (Eab) expressing toughness depended on the shearing strain rather than the shearing stress and was inclined to become larger with the increase in temperature. However, the variation of Eab up to 400°C was small and remarkably large at 600°C. Eab decreased as the carbon content increased in the specimens irrespective of the chromium level. Eab of the as-cast specimen was always larger in the order of 30%, 15% and 5%Cr cast iron, however, was conversely reduced by annealing because of the precipitation of the coarse continuous carbides in the matrix.抄録全体を表示PDF形式でダウンロード (816K)
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