巻号一覧
後続誌
46 巻, 5 号
選択された号の論文の7件中1～7を表示しています
- |<
- <
- 1
- >
- >|
研究論文
-
高瀬 孝夫, 中村 康彦, 高田 良規1974 年 46 巻 5 号 p. 415-421
発行日: 1974/05/25
公開日: 2012/09/20
ジャーナル フリーThe liquid nitriding (Tufftride process) is being used for machine parts for improving fatigue strength and resistance to wear and seizure in cast iron. Silicon, which is dissolved in great amount in α-iron of cast iron, has an important effect on the nitriding. In this study, Fe-Si and Fe-C-Si alloys were nitrided by Tufftride Process at 570°C for 1-6 hours for a basic study on the nitriding of cast iron.
The compound and diffusion zones in Fe-Si alloy were obtained by the nitriding. The compound zone consists of ε(Fe2-3N), γ'(Fe4N) and Si3N4. Nitrogen of ε nitride was determined by X-ray diffraction and its value was estimated to be about 8%. The existence of Si3N4 in samples which were annealed at 700°C and extracted by ammonium persulphate solution was confirmed by means of X-ray diffraction and electron microscopy.
The values of maximum hardness in the compound and diffusion zones increased together with the increase of amount of silicon which forms a very fine Si3N4 compound. As the silicon content increased, the diffusion constant declined as a result of the reduction of compound and diffusion zones. Precipitate free zone has been found in the diffusion zone which was tempered at 300°C after being quenched from the nitriding temperature. This means that γ' (Fe4N) could not be precipitated from α solid solution due to the lack of dissolved nitrogen. The width of compound zone and diffusion constant in Fe-C-Si alloy decreased in proportion to the silicon content; and their values were smaller than those in Fe-Si alloy.抄録全体を表示PDF形式でダウンロード (880K) -
手塚 秀男, 葉山 房夫1974 年 46 巻 5 号 p. 422-428
発行日: 1974/05/25
公開日: 2012/09/20
ジャーナル フリーAn investigation was conducted to clarify the stress-strain properties of gray cast iron at elevated temperatures up to 700°C under tensile stress. Hardness at elevated temperatures was also measured to examine the correlation between the stress-strain properties and the hardness of matrix.
Elastic modulus of cast iron under tensile stress at both elevated temperature and room temperature decreased linearly as tensile stress increased. Hardness of cast iron decreased as temperature rose and this downward propensity of hardness was very different in different temperature ranges. In the range from room temperature to 100°C, hardness decreased to a certain degree, it decreased slightly in the range 100∼400°C, and then rapidly in the 400∼700°C. Hardness and elastic modulus at elevated temperatures showed similar tendencies according to the testing temperatures. They showed relatively little change at temperatures below 400°C, but decreased markedly above 400°C.
Diagrams of total and permanent strain ε, εp and stress σ-strain ε of cast iron under tensile stress can be expressed well by the following empirical formulae.
εp=βeασ, ε = (σ+E0βeασ-mβeασ·σ)⁄(E0-mσ)
where α and β are constant, m and E0 are respectively the coefficient of Young's modulus at zero stress level of cast iron.抄録全体を表示PDF形式でダウンロード (799K) -
陣山 展夫, 古宮 志郎, 戸崎 宏, 藤田 幸男, 谷村 凞1974 年 46 巻 5 号 p. 429-435
発行日: 1974/05/25
公開日: 2012/09/20
ジャーナル フリーChilling effect and ferrite formation should be avoided in order to obtain thin-wall gray iron castings having high quality. The influences of mold and inoculation on the strength and microstructure of thin-wall gray iron castings were investigated in relation to the cooling rate.
The microstructure of thin-wall castings having composition of high carbon equivalent is composed of fine graphite of eutectic form and ferrite. When the cooling rate increased, the amount of ferrite in the structure decreased and the tensile strength increased. When the cooling rate is kept constant, the thinner the thickness of castings, the more the ferrite ratio is.
Inoculation is effective to prevent chilling effect. The use of combination of 75% ferrosilicon and tin as inoculant is useful to obtain thin-wan castings having high strength. The mechanical properties of round-bar test piece (diameter D) are somewhat better than those of plate test piece (thickness T) under conditions D=2T.抄録全体を表示PDF形式でダウンロード (751K) -
宮手 敏男1974 年 46 巻 5 号 p. 436-440
発行日: 1974/05/25
公開日: 2012/09/20
ジャーナル フリーEffects of phosphorus or sodium addition on the microstructures and mechanical properties of the Al-(11.7∼25)%Si alloys were studied.
With the addition of both phosphorus and sodium, primary silicons and eutectic structures were modified and their mechanical properties were improved more than by the addition of phosphorus or sodium alone. The amount of phosphorus and sodium sufficient to obtain the most desirable mechanical properties varied with the content of silicon in the alloys. That is, the adequate amount was 0.1% in phosphorus and 0.3% in sodium in the case of the Al-18%Si alloy, and 0.1% in phosphorus and 0.1%, sodium in the Al-25%Si alloy. When excessive sodium, that is more than the quantity mentioned above, was added, overmodified structures were obtained, and the mechanical properties were poorer than in the case of phosphorus addition.抄録全体を表示PDF形式でダウンロード (861K) -
ティエリ・ クルザティエ, 中島 宏興, 倉部 兵次郎1974 年 46 巻 5 号 p. 441-447
発行日: 1974/05/25
公開日: 2012/09/20
ジャーナル フリーThe purpose of this study is to appraise and attempt to explain the differences in the results of mechanical tests of cast and forged Cr-Mo steels.
Tensile strength, yield strength, uniform elongation and impact transition temperature were about the same in the cast and forged steels. Elongation at fracture, reduction of area and impact value of longitudinal section of forged specimens were better than those of cast steel.
For the attempt to explain these differences, four factors have been investigated : grain size, segregation, microporosity and directionality of structure. Differences in grain size and segregation in the froged and cast specimens did not explain the differences in mechanical properties. Microporosity of cast steel had a big influence on the reduction of area and elongation and also there was a slight influence on impact values. On the other hand, directionality of structure had a weak influence on the values of reduction of area and elongation but was a predominant factor in the impact values.抄録全体を表示PDF形式でダウンロード (732K) -
大出 卓, 大平 五郎1974 年 46 巻 5 号 p. 448-454
発行日: 1974/05/25
公開日: 2012/09/20
ジャーナル フリーThe variation in the morphology of eutectic carbide in white cast iron has not been verified, alfhough there are a number of papers on the structure of white cast iron, which solidifies as plate-like or rod-like eutectic carbide, according to the differences in the composition and the solidification rate. In this paper, a close investigation was made on the relation between carbon and chromium content and solidification rate in the hypo-eutectic white cast iron molten in a Tammann tube and a silica crucible.
A remarkable decarburization of melt was observed on silica crucible melting. Accompanying the undercooling and recalescence of eutectic temperature, plate-like eutectic carbides were formed when carbon, chromium content and solidification rate were within certain values. The formation of the plate-like eutectic carbide was dependent on the ratio of the time required from primary to eutectic solidification and the time required for eutectic solidification. The type of plate-like eutectic structure was between the stable Fe-C system and the metastable Fe-Fe3C system.抄録全体を表示PDF形式でダウンロード (1058K) -
上田 俶完, 國光 誠司1974 年 46 巻 5 号 p. 455-461
発行日: 1974/05/25
公開日: 2012/09/20
ジャーナル フリーA kinetic study on the effect of magnesium on the first-stage graphitization in white cast iron containing magnesium in a commercial range of composition, was made vis-a-vis the graphitization time, incubation period and activation energy for graphitization. Two types of the graphitization models, proposed by Burke and Owen, and Ferry, were evaluated from the results. Metallographic observations were also carried out in order to find out the effect of magnesium on the graphite morphology after graphitization.
Magnesium up to 0.064% promoted first-stage graphitization and reduced incubation period. The morphoplogy of temper carbon was transitional in the range of magnesium content between 0.022% and 0.045%, and became close to spherical above 0.045%Mg. As magnesium increased, the number of nodule of temper carbon increased and the size of the nodule became smaller. This coincided with the promotion of the first-stage graphitization. From results of the present work, Burke and Owen's model was found to be more reasonable than Ferry's. The activation energy for graphitization estimated from Burke and Owen's model was reduced from 49kcal/mol to 28kcal/mol with the increase of magnesium content from nil to 0.064%.抄録全体を表示PDF形式でダウンロード (751K)
- |<
- <
- 1
- >
- >|