日本金属学会誌
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
27 巻, 6 号
選択された号の論文の10件中1~10を表示しています
  • 中沢 一雄
    1963 年 27 巻 6 号 p. 245-250
    発行日: 1963年
    公開日: 2008/04/04
    ジャーナル フリー
    On the six hypereutectoid alloy steels, the effects of austenitizing temperature and holding time on the Ms point have been investigated by dilatometric method. In view of the fact that the lowering of the Ms point results from dissolution of the carbide in the austenite and when dissolution is finished the Ms point reaches the constant value, activation energy of carbide dissolution for the three Cr steels with different carbides was derived from the relation between the time required for the Ms point to reach the constant value at each austenitizing temperature and the austenitizing temperature. Their values were 74300 cal/mol (1.02%C and 1.99%Cr: θ carbide), 55600 cal/mol (0.96%C and 9.37%Cr: η carbide) and 50700 cal/mol (0.26%C and 12.97%Cr: ε carbide). From the results obtained, it has been considered that the process of carbide dissolution relates to the compositions of the carbide and the neighbouring austenitic matrix and to the quantity of the dissolved carbide and moreover the mechanism of carbide dissolution is not a simple diffusion process. In the case of addition of 3.82%W, 0.50%Ti and 1.40%V respectively to 1%C∼2%Cr steels, the Ms points became higher as a whole than in the case of no addition, especially remarkable in addition of vanadium. Their behaviors may have revealed the dependence of carbon content of the austenite on the solubility of the special carbide formed by each additional element and moreover the effect of each additional element dissolved in the austenite on the Ms point.
  • 大日方 一司, 栗原 健助, 竹内 庸, 渡辺 正晴
    1963 年 27 巻 6 号 p. 251-256
    発行日: 1963年
    公開日: 2008/04/04
    ジャーナル フリー
    Es ist neuerdings von den Verfassern gelungen, reine Mangan-Kalzium-Legierungen mit gewünschten Zusammensetzungen durch Lichtbogenschmelzverfahren herzustellen, das darin besteht, Einsatz von Mangan und Kalzium im Lichtbogenofen mit Wolframelektrode in einer wassergekühlten Kupferkokille unter Argon zu erschmelzen. Auf Grund der Ergebnisse der Gefügeuntersuchung und chemischen, thermischen Analysen an den Knopfschmelzproben wurde ein Zustandsdiagramm für das System Mangan-Kalzium vorgeschlagen. Im System Mangan-Kalzium ist keine intermetallische Verbindung vorhanden. Die beiden Metalle sind im flüssigen Zustand nur teilweise mischbar und bilden eine Mischungslücke. Eine monotektische Reation findet bei 1252°C statt, bei der die manganreiche Schmelze mit etwa 0.5% Kalzium unter Ausscheidung des Manganmischkristalls mit geringem Kalziumgehalt in die kalziumreiche Schmelze mit etwa 2.7% Mangan umwandelt. Kalziumschmelze vermag bei 1200°C bis zu 2.52% Mangan und bei 900°C bis zu 1.25% Mangan zu lösen. Anderseits löst sich Kalzium im festen Mangan bei 1100°C bis zu mindestens 0.34%. Die Mischungslücke des Systems Mangan-Kalzium erstreckt sich weit über das ternäre System Mangan-Kalzium-Silizium und schliesst sich bei etwa 32% Silizium, 34% Mangan.
  • 中村 文俊, 斎藤 省三, 岡林 邦夫
    1963 年 27 巻 6 号 p. 257-262
    発行日: 1963年
    公開日: 2008/04/04
    ジャーナル フリー
    Vavious theories, such as those of Bowden-Tabor (theory of adhesive wear), Kerridge (theory of metal transfer), Feng (plastic roughening theory) having been presented, wear phenomena have been made clear to some extent. The details of wear phenomena, however, are still unknown on account of their complexity. The purpose of this study is to show the reason why those theories cannot well explain the experimental results, and also to find out the factor on dry wear. Special wear tester was made for this study and in this report, the outline of the wear tester and the results of preliminary test are described. Preliminary tests showed the satisfactory results, and it is pointed out that the working accuracies of wear tester and specimen have an effect on the reproducibility of experimental results.
  • 増本 量, 斎藤 英夫, 小林 猛郎
    1963 年 27 巻 6 号 p. 263-265
    発行日: 1963年
    公開日: 2008/04/04
    ジャーナル フリー
    The density ρ, Young’s modulus E, the thermal expansion coefficient α, and the temperature cofficient of Young’s modulus e were measured with the alloys of iron and palladium cooled in a furnace after having been annealed at 1000°C to asscertain whether the rule on the small expansibility of Invar proposed previously by one of the present investigators is valid in the above alloy system or not. It was found that both the curves of ρ and of E against the alloying concentration show respectively, slight bends at the composition of 30 at.% of palladium, and also α shows its minimum value of +8.9×10−6 and e its conspicuous positive maximum value of +139.9×10−5 at the composition mentioned above. The alloy containing 30 at.% of palladium is composed almost of γ phase after a furnace cooling, but when it was cooled more slowly than 30°C/hr from 800°C, the amount of the γ phase decreased. It was 0 at the cooling rate of 5°/hr, and an increase of α to +12.3×10−6 and a decrease of e to −12.5×10−5 resulted, both of these magnitudes being of the order of usual alloys. According to these results, it can be confirmed that the rule on Invar mentioned above can also be valid in the system of iron and palladium under all the conditions.
  • 赤須 英夫
    1963 年 27 巻 6 号 p. 266-270
    発行日: 1963年
    公開日: 2008/04/04
    ジャーナル フリー
    Time-temperature-austenitization diagrams (T-T-A Diagrams) were plotted to provide a guide for rapid heating and quenching of structural alloy steels like Ni-Cr (C 0.31%, Ni 1.45%, Cr 0.63%), Cr(C 0.39%, Cr 1.06%) and Cr-Mo (C 0.38%, Cr 0.96%, Mo 0.18%) steels. Specimens, 3 mmφ×10 mm, were preheated to impart them different structures: lamellar structure and fine spheroidized structure (quenched and tempered structure). For this purpose, they were heated in lead bath for different durations and then rapid-quenched in water. The T-T-A diagrams were plotted from the changes in hardness and microstructure. (1) From these diagrams, the starting and finishing times of austenitization were determined with the process of austenitization made clear. (2) Austenitization started nearly at the same time in all steels, but finished much sooner in ones of fine spheroidized structure than in ones of lamellar structure. After finishing of austenitization, with increase of the holding time, the coarsening of martensite acicula obtained by quenching occurred slower in the former than in the latter. The former structue would be more effective for the purpose of quenching. (3) In all steels, austenitization began nearly at the same time, but finished in Ni-Cr as well as 0.40%C steel at the shortest time, followed by Cr and Cr-Mo steel, the last one taking the longest time. For appropriate quenching, the holding time should be chosen for each steel.
  • 高橋 俊夫, 勝野 久治
    1963 年 27 巻 6 号 p. 271-277
    発行日: 1963年
    公開日: 2008/04/04
    ジャーナル フリー
    High aluminium iron alloy is difficult to roll, and in spite of its high permiability it is not commercially developed. This study is carried out for the purpose of determination of the best rolling process of the 12%Al-Fe alloy. The design of experiment was adopted in order to determine the optimun process, and then L16 orthognal array modified is used. There are six factors for forging, hot rolling and cold rolling, and two or four levels in each factor. The optimum working condition obtained for 12%Al-Fe alloy is as follows: The cast slab is (1) forged at 1000°C, (2) hot rolled repeatedly from 700°C to total reduction above 80%, (3) cold-rolled continuously after hot rolling, and (4) cold-rolled after quenching from 650°∼700°C after 50% cold-roll to obtain thinner sheet. According to this process, 12%Al-Fe alloy can be cold-rolled up to 99% reduction and a thin sheet of 0.12 mm thick can be obtained. It is concluded that the better workability of this alloy is developed by the fiber structure formed during hot rolling about 700°C, and this fiber structure increases toughness and strength of alloy in the direction of rolling. The mechanical properties of thin sheets are the tensile strength of 85 kg/mm2 and the elongation of 15% in maximum.
  • 竹内 栄, 本間 敏夫, 佐藤 経郎
    1963 年 27 巻 6 号 p. 278-283
    発行日: 1963年
    公開日: 2008/04/04
    ジャーナル フリー
    The reaction of thorium metal with graphite was studied in the temperature range of 900°∼1600°C. It was found that the reaction rate was parabolic, and the activaion energy for the reaction was 53 kcal/mole below 1200°C. Marker experiments showed that the growth of carbide film was caused mainly by the migration of carbon. From these results,the rate determining process of the reaction seems to be the diffusion of carbon in the carbide film formed on the metal surface. Hydrocarbons, yielded by hydrolysis of the carbide film, were analysed by gas chromatographic method, from which the ratio of ThC/ThC2 in the carbide film was determined. The film formed below 1200°C was composed of ThC only. However, in the film formed above 1300°C the ratio of ThC/ThC2 decreased with increasing temperature. The activation energy for ThC2 formation was 140 kcal/mole. The diffusion coefficient of carbon in ThC was calculated from the parabolic rate constants. The amount of thorium carbide, which would form in a thorium blanket of graphite matrix fuel reactor, was estimated.
  • 六碕 賢亮, 鈴木 正敏, 河合 栄一郎
    1963 年 27 巻 6 号 p. 283-288
    発行日: 1963年
    公開日: 2008/04/04
    ジャーナル フリー
    In the electrical-discharge machining, the eroded surfaces were often affected by working media or electrode materials, not only to their crystal structures, but also to compositions. The surfaces of some steels, eroded by electrical-discharge, using of kerosene as working media, were examined by X-ray diffraction and optical microscope. The eroded surfaces were carburized abnomally, and some rapid-melted and rapid-solidified layers of high carbon or white-pig-like structures were found.
  • 中山 忠行, 庄司 文夫, 八木 栄一
    1963 年 27 巻 6 号 p. 289-292
    発行日: 1963年
    公開日: 2008/04/04
    ジャーナル フリー
    The present authors studied oxidation behaviors of Ti-Zr alloys (ca.5∼90 wt%), using the thermo-balance, X-ray diffraction, electron microscope and optical microscopic methods. The catastrophic oxidation was observed in alloys containing ca. 50∼90 wt%Zr oxidized in air at 700° or 900°C for 30 min or 2 hr. It was verified experimentally that β-phases (cubic type crystals) remaining in substrata were more preferentially oxidized than α-phases (hexagonal close-packed crystals) in the earliest stage of oxidation (500°C, 5 min) of the alloys showing the catastrophic oxidation at 700° or 900°C, and moreover, that these alloys showed breakaway phenomena of the surface oxide scales. The present studies also clarified by X-ray diffraction and optical microscopic observations that the surfaces were mainly covered with porous TiO2ZrO2 or TiO2ZrO2 and ZrO2 layers in the alloy showing the catastrophic oxidation.
  • 井上 繁弘, 土屋 隆
    1963 年 27 巻 6 号 p. 293-298
    発行日: 1963年
    公開日: 2008/04/04
    ジャーナル フリー
    Effect of Fe (0∼10%) on the properties of Ni-Mo alloys was investigated by hardness, tensile, microscopic and corrosion tests. The following results were obtained. (1) With increasing content of Fe, both the corrosion loss and the strength of solution-treated Ni-Mo alloys increased, but the elongation lowered remarkably. (2) When air-cooled from annealing temperature of 700°C, the lower Fe contents, the more appreciably deteriorated the corrosion resistance and the elongation. This may be attributable to the procipitation of carbide on grain boundaries, the amount of which suppressed by the addition of Fe. Therefore, the minimum corrosion loss of the alloys annealed at 700°C was obtained by the consistent Fe content, which depended on the holding time at the annealing temperature. (3) With increasing content of Fe, the hardness aged at 700°C decreased, but at 850°C increased. It may be deduced that the addition of Fe to Ni-Mo alloys varys the form the precipitation of β phase at 700°C and favours the precipitation of γ phase at 850°C.
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