Journal of the Japan Institute of Metals and Materials
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
Volume 20 , Issue 7
Showing 1-15 articles out of 15 articles from the selected issue
  • Masayoshi Tagaya, Imao Tamura
    1956 Volume 20 Issue 7 Pages 357-360
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    In comparing the cooling curves which conform to Newton's law of cooling, with the mother cooling curves presented in our 8th report in terms of cooling time from 800° to different terminal temperatures, the relation between the quenching severity and the terminal temperature was introduced (Fig. 4). The severity of quench changes with the terminal temperature corresponding roughly to the main three stages of cooling process and has a maximum value at about the beginning temperature of the convestion stage revealing the characteristics in the cooling process for each coolant. There are tendencies that the severity of quench shows larger value for the surface of the specimen than that for its center and the smaller the dimension of specimen the larger is the severity of quench.
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  • On the Distribution of Hardness and Structure Cauesed by Cold Drawing, and Some Considerations on the Phenomena (1)
    Waichi Ota
    1956 Volume 20 Issue 7 Pages 360-363
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    The hardness distribution both on a transverse section and an oblique section of cold drawn Armco iron and nickel was measured in detail, and it was clarified that three steps in the surface, the middle and the centre parts appeared in the hardness distribution. Moreover, the relationships of the hardness change to the reduction of one pass and of the hardness distribution to residual internal stress were studied.
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  • On the Distribution of Hardness and Structure Caused by Cold Drawing and Some Considerations on the Phenomena. (II)
    Waichi Ota
    1956 Volume 20 Issue 7 Pages 363-367
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    The changes in distribution of structure caused by cold drawing were studied microscopically and the different structures appeared at three parts, i. e. the surface, the middle and the centre, respectively. The process of hardness distribution at three steps in the drawing die was clarified. Then the effect of cold drawing and subsequent annealing upon the mechanical properties was studied.
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  • The Isothermal Transformation in Intermediate and Martensite Ranges
    Hideji Hotta, Itsurô Tatsukawa
    1956 Volume 20 Issue 7 Pages 368-371
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    The authors determined the isothermal transformation diagrams in temperature ranges of 180-600°for structural Ni-Cr-Mo steel (0.52C, 1.58Ni, 0.71Cr, 0.56%Mo) and Cr-Mo steel (0.47C, 0.93Cr, 0.46%Mo) by micrography and hardness test, and then inspected the relation between isothermal transformation and retained austenite at room temperature, using the measurement of thermal dilatation during austempering as well as tempering after austempering. The results obtained are summarized as follows: (1) In the intermediate range (330-500°), austenite transforms to lower-bainite, wich finally breaks down to α+θ aggregate. (2) In the martensite range (below 300°), austenite firstly transforms to martensite during an surely period of cooling below Ms temperature, and then to lower-bainite isothermally, the latter transformation being delayed with the lowering of the hot-bath temperature. (3) After austempering at a fixed temperature in martensite range, the amount of retained austenite at room temperature increases with the time of holding in hot-bath, reaches a maximum at an intermediate period of lower-bainite formation, and then decreases.
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  • K. Iwase, K. Ogawa, S. Fujishiro
    1956 Volume 20 Issue 7 Pages 371-375
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    Among the carbides, the nitrides, the borides and the silicides of the transition metals, molybdenum disilicide has been less studied upon than the others, though its samples are rather easily available as refractory hard metal pieces. It is, however, relatively difficult to prepare pure samples of the compound, as the vapor pressures of Mo and Si differ much from each other (the vap. press. of Si: 1mm Hg at 1, 219°C according to I. C. T.). After examining the conditions for preparing solid MoSi2 by powder method, we succeeded in obtaining samples of high purity MoSi2 (99.6%), which we subjected to X-ray and chemical analysis. In experimenting for the effects of the following factors, namely, the particle size of the powders, the duration of the mixing time, the temperature and the atmosphere of reaction and the ratio of mixture to reaction kinetics, we found that the most important condition is to add several percents more of Si than is stoichiometrically evaluated prior to the process, as explained in § III-3-(4) and Fig. 4 and 5 below.
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  • Riitsu Takagi, Kiyoshi Tamura, Susumu Yoshida
    1956 Volume 20 Issue 7 Pages 375-377
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    The sample of CrB arc-melted in an argon atmosphere in a water coold copper crucible was pure than that obtained by sintering a mixture of Cr2O3, boron and carbon black powders. The former was subjected to the following studies. It was ground, pressed and sintered to form test specimens. The optimum sintering temperature is ca. 1600-1700°. The resistance to oxidation at 1100° and corrosion against HNO3, HCl and H2SO4 is rather bad except in the case of HNO3. The ability of wetting CrB is shown to be best in Ni and to go worse in the order Fe-Cr-Co-Cu-Ag. Ag scarcely wets CrB. The reaction zones were examined by metallographic method and hardness test.
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  • On Cold Impact Extrusion of Magnesium and its Alloy
    Isao Gokyu, Hisashi Suzuki, Kimiatsu Shinji
    1956 Volume 20 Issue 7 Pages 378-381
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    Studies on cold backward impact extrusion of Magnesium and Dow Metal FS were carried out. The results of experiments were as follows: (1) Static extrusion of these metal and alloy was impossible at extruding temperatures approximately 100° or less. (2) But these were successfully cold-impact- extruded with more than 80-90% reduction in area. (3) Influences of reduction in area and annealing temperatures of blanks on cold impact extrusion forces were therefore investigated at higher reductions, and the annealing temperature of about 200° was found to minimize the extrusion forces. (4) The properties of cold-extruded shells, such as the hardness distribution, the microstructure, and the extruding texture were explained. (5) The earing behavior and some defects during extruding have been described also.
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  • Hidetake Kusamichi, Yoshiro Yagi, Toru Yukawa, Kazuo Miyamoto
    1956 Volume 20 Issue 7 Pages 381-385
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    The effects of hydrogen and carbon on the weldability of commercially pure titanium were studied and the following results have been obtained. Hydrogen in titanium increases the tensile and yield strength with decreased ductility, but there is no difference between the unwelded and welded high-hydrogen specimens. The welded specimens containing 0.04 and 0.12% carbon showed about the same mechanical properties as the unwelded specimens. However, the 0.29% carbon-specimen, upon welding, showed a considerable decrease in bend ductility. Porosity in welds, which did not seem to have a direct relation to the hydrogen and carbon contents, was decreased effectively by using a higher welding current.
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  • Zenji Nishiyama, Ken'ichi Shimizu, Shin'ichi Satô
    1956 Volume 20 Issue 7 Pages 386-388
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    Electron and optical microscopic examinations have been carried out on the mid-rib of a martensite using Fe-30% Ni alloy and Kovar. The results are as follows: (1) In the surface relief of Fe-30% Ni alloy, most of the martensite plates seem to have a ridge, on opposite sides of which the direction of fine bands is slightly different, the largest difference being about 7°. The ridge may be considered to correspond to the mid-rib. (2) On the etched surface of Fe-30% Ni alloy, there are occasionally found martensite plates which have two parallel mid-ribs 1μ apart or the transient region from one mid-rib to another. (3) On the etched surface of Kovar, step structures are founed in a mid-rib of the martensite.
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  • T. Ichiyama, T. Nagai
    1956 Volume 20 Issue 7 Pages 388-392
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    When certain non-cubic metals and alloys are subjected to cyclic thermal treatment, plastic deformation results from the anisotropy of thermal expansion inherent in these metals and alloys. In this paper, the plastic deformation of zinc polycrystals caused by thermal cycles is described. The specimens cycled at higher temperature ranges show, in addition to the usual deformation by slip, kinking and micro-kink bands in some grains and also grain boundary sliding and migration. Slip bands, and kinking and boundary migration were already detected by a hot-stage microscope at about 50°, and about 100° respectively. No abnormal slip has been detected in all the specimens cycled thermally. The surface rumpling of the specimens results mainly from kinking and cell structures are formed readily in some grains as a result of kinking. The specimens cycled at lower temperature ranges show slip bands, micro-kink bands, micro-ridges, twins, accommodation kinks and cleavage cracks. Slip bands and micro-kink bands were already detected after one cycle between 15° and -30°. The formation of micro-kink bands becomes more pronounced in all grains as the minimum temperature of the cycle is lowered. Micro-kinklng may be the principal mechanism of plastic deformation at low temperatures. Twins and cleavage cracks were detected in some grains after one cycle between 15° and -100° and between 15° and -190°, respectively. Some grains showed signs of cleavage cracking after only one cycle even over the range 15° and -150°.
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  • T. Ichiyama, T. Nagai
    1956 Volume 20 Issue 7 Pages 392-396
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    Mechanical twinning and de-twinning are caused by thermal cycles at lower temperature range in zinc polycrystals. Most of the twins nucleate at grain boundaries, and there are some indirect evidences supporting the hypothesis of three-stage process in twinning introduced by Bell and Cahn. The twins produced by thermal cycles at lower temperature range may grow thermally or mechanically and also disappear mechanically during thermal cycles at higher temperature range. One of the two interfaces of each twin lamella is fixed during mechanical growth of twin and the twin grows from only one side of the twin lamella. The matrix in the vicinity of the fixed interface is in a highly strained condition and the fixed interface can be made to move in the matrix by thermal cycle at higher temperature range. Therefore, it seems that the mechanical growth of twin nuclei is restrained by lattice disturbance in the highly strained material. The thermal migration of the fixed interface may be considered as strain-induced boundary migration.
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  • Mikio Yamamoto
    1956 Volume 20 Issue 7 Pages 396-400
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    It is shown that the anisotropy of the solution rate along any direction, υ, and that of the radius vestor along the same direction, γ, from the origin to the circumference of a solution body produced from an originally sphere crystal, are generally expressed by υγ=υcγc•cos4θ+(υaγa•cos22φ+υbγb•sin22φ)sin4θ+(4•υdγdcγcaγa)cos2θsin2θ for tetragonal crystals, by υγ=υcγc•cos6θ+(υaγa•cos23φ+υbγb•sin23φ)sin6θ+1/3(24•υdγd-8•υeγe-10•υcγc+3•υaγa)cos4θsin2θ+1/3(-8•υdγd+24•υeγe+3•υcγc-10•υaγa)cos2θsin4θ for hexagonal crystals, and by υγ=υcγc•cos6θ+(υaγa•cos23φ+υbγb•sin23φ)×sin6θ+1/3{12(υdγdgγg)-4(υeγefγf)-10•υcγc+3•υaγa}cos4θsin2θ+1/3{-4(υdγdgγg)+12(υeγefγf)+3υcγc-10υaγa}cos2θsin4θ+(4/√3){-(υdγdgγg)+(υeγefγf)}cosθsin3θcos3φ+(16/3√3){3(υdγdgγg)-(υeγefγf)}cos3θsin3θcos3φ for rhombohedral crystals, where θ and φ are, respectively, the polar and azimuthal angles of the direction referred to a polar coordinate system of which the polar axis and zero line for φ are, respectively, the [001]and [100]axes for tetragonal crystals, the [0001]and [1010]axes for hexagonal crystals, and the [111]and [211]axes for rhombohedral crystals.
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  • N. Ohtani
    1956 Volume 20 Issue 7 Pages 400-403
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    Assuming that the corrosion of pure iron is controlled equally by anode and cathode reactions, the electrochemical properties of the stressed ayer of the surfaces of specimens polished by various methods, that is, the order of the variation of the thickness, the electrode potential of the layer and the free energy of the activation of hydrogen electrode reaction were researched.
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  • Measurement of Spontaneous Potentital and Corrosion of Titanium
    Susumu Morioka, Akimi Umezono
    1956 Volume 20 Issue 7 Pages 403-407
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    The reason why the spontaneous potential of titanium vibrates periodically to positive and negative directions in distilled or tap water, changing gradually to positive value with time, is that the positive and the negative ions accumulated in anodic (in pin holes of the oxide film) and cathodic (the oxide film) areas respectively, are not neutralized until they attain a certain amount in water. The spontaneous potential of titanium changes to a negative value with time in such solutions under natural aeration as HF>0.005%, HCl>10%, H2SO4>5%, H3PO4>30%, NH4F>0.01%. On the contrary, in such solutions as of HNO3, CrO3, K2Cr2O7 and K2MnO4 in acid solutions, Cu++, Fe+++, Ag+, it varies largely to a positive value and titanium is passivated. The corrosion rate of titanium in naturally aerated HF, H2SO4 or HCl solutions containing different oxidizing agents was measured.
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  • Measurement of Polarization of Titanium
    Susumu Morioka, Akimi Umezono
    1956 Volume 20 Issue 7 Pages 407-411
    Published: 1956
    Released: December 25, 2008
    JOURNALS FREE ACCESS
    When the anodic polarization curves of titanium are measured in a solution wherein the corrosion potential of titanium varies to positive direction with time, the potential of titanium becomes constant between 1.7 to 1.9 volt (vs. S. C. E.) while the anodic current density is increased and the curve has an arrest. The arrest, which corresponds to the oxygen evolution potential, on the polarization curve can be found in neither measurement, the one performed in a solution in which the corrosion potential of titanium varies to negative direction with time and the other carried out with the titanium surfae pretreated so that the natural oxide film is reduced cathodically or chemically. From these experiments and electron diffraction studies, it is concluded that the oxide film of titanium produced by electrochemical oxidation is different from the natural oxide film formed in air, and that the former is of rutile type, non-conductive crystals and the latter is presumably of rutile type, conductive crystals. An anatase type TiO2 is formed only when titanium is oxidized in the solution without applied current.
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