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Volume 17, Issue 3
Displaying 1-13 of 13 articles from this issue
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Isao Gokyu, Hideo Abe1953 Volume 17 Issue 3 Pages 101-104
Published: 1953
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (583K) -
Ryuzo Ueda1953 Volume 17 Issue 3 Pages 105-108
Published: 1953
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe grain growth of austenite at high temperatures as observed by means of the emission-type electron microscope proceeds as follows: (a) On heating a specimen of plain carbon steel or Ni-Cr-Mo steel from room temperature to a certain temperature above A3 point, fine austenite grains filling the whole surface at first diminish rapidly in number, but the rate of diminution falls suddenly at a certain stage. The grain growth accompanied by the smoothing of zigzag boundaries becomes sporadic (Photo. 1, 2). (b) If then the specimen is cooled for a few seconds just below A3 point and at once restored to the previous temperature, the original pattern is preserved except at boundary regions between grains where vigorous recrystallization occurs (Photo. 4a-e). This fact means that the decomposition of austenite grains on cooling below A3 point begins at their peripheries. (c) Austenite grain boundaries as seen electronmicrographically (1) below about 1000° are only geometrical lines between light and shade, but (2) when heated at about 1150° for 10∼30 minutes, they begin to have actual breadth (Photo. 4g, h) and (3) at the same time some uniformly emitting grains begin to take on network pattern on the whole surface (Photo. 4g, h). Correspondingly on the cooled specimen surface we observe respectively (1) very fine grooves, (2) broader ones and (3) irregular furrows about 30μ apart. (d) Twin bands grow differently from the ordinary grains in that (1) they change only in length but not in width (Photo. 4c-h) and their breadth suffers no alternation even when cooled for a few seconds below A3 point (Photo. 4a, b) and (2) the straight parallel lines marking twin boundaries are either entirely not or only slightly perceptible as grooves on the cooled specimen surface, and do not broaden when heated at a very high temperature (1200°) (Photo. 4g, h).View full abstractDownload PDF (828K) -
Denjiro Watanabe, Shiro Ogawa, Takashi Kimura1953 Volume 17 Issue 3 Pages 108-113
Published: 1953
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe surface products due to the selective oxidation of Cu-Al alloys (1∼10%Al) heat-treated at 500∼800° for 15 min in hydrogen stream saturated with water vapour were examined by the electron diffraction method. In case of specimens which highly resisted the discolouration the patterns obtained did not agree with that of γ-Al2O3, but were similar to that obtained previously by Harrington et al. The subsequent gas-heating of these surfaces caused the films to change into γ-Al2O3 which had, however, a lattice symmetry slightly different from that of the ordinary spinel type. The refraction effect of electrons due to minute crystals of CuO produced on the alloy surface was also observed.View full abstractDownload PDF (1002K) -
Mikio Yamamoto, Jirô Watanabé1953 Volume 17 Issue 3 Pages 113-118
Published: 1953
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe procedure for a perfect, accurate and rapid determination of orientations of tetragonal tin single crystals by the use of light figures has been worked out. Full accounts are given of necessary geometrical relationships, etching technique, measurable ranges and kinds of angles, stereographic representation of crystal orientations, and the accuracy with reference to various actual examples. It is shown that perfect determination of crystal orientations can be made with an accuracy well within 1° by the use of the {001}, {100} and {101} light figures produced by etching with concentrated aqua regia.View full abstractDownload PDF (822K) -
Mikio Yamamoto, Jirô Watanabé1953 Volume 17 Issue 3 Pages 118-122
Published: 1953
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPhenomenon of solution bodies has been investigated with bismuth single crystals of circular rod and sphere forms etched with various reagents and some information as to the anisotropy of solution rate have been obtained. By etching with 31.6 percent nitric acid, a circular-rod crystal of which the rod axis is nearly parallel to the [111] direction converted into a hexagonal prism and crystals of which the rod axes are nearly parallel to the [\bar101] or [\bar211] directions transformed into elliptical rods. Also, a spherical crystal converted into a rugby ball-like shape of which the long axis coincided with the [111] direction and the surface was surrounded with six curved faces. From the relation of the forms and dimensions of the solution body produced with crystal orientations, it has been found that the relative rates of solution in 31.6 percent nitric acid along various crystal directions are in a ratio V⟨111⟩:V⟨011⟩:V⟨001⟩:V⟨111⟩:V⟨\bar111⟩:V⟨\bar101⟩=1.00:1.07:1.14:1.19:1.20:1.40. Reagents other than 31.6 percent nitric acid did not produce any clear-cut solution body. It was found, however, that the series of rates of solution in 50 percent aqueous solution of 1:2 mixture of hydrochloric acid and nitric acid (61.7%) was V⟨111⟩<V⟨\bar211⟩\doteqdotV⟨\bar201⟩.View full abstractDownload PDF (772K) -
Nobuo Nakamura, Yutaka Sato1953 Volume 17 Issue 3 Pages 122-125
Published: 1953
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSRegarding pelletizing, we have recently heard reports on various theories about the mechanism of forming wet balls in a balling drum. Most of those theories described simple mechanical mechanism. One of the authors also investigated on this matter a few years ago, and contributed a new theory of “The Arrangement Effect.” According to a author’s calculation, the so-called capillary force, was not so effective in giving strength to the wet ball as long as it was constructed by the grog of particles about 10−4 cm in radius, but, if it were bound with some colloidal matters, the capillary force should be about 50 kg per square cm between any two particles in a pellet. Further-more, a new theory from the physico-chemical point of view should be introduced in this field. It will be given in detail in our next paper (II).View full abstractDownload PDF (624K) -
Nobuo Nakamura, Yutaka Sato1953 Volume 17 Issue 3 Pages 126-129
Published: 1953
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the previous report (I), the authors described the physical mechanism of pellet glomerizing in a balling drum. In this report (II), we show the results investigated on the chemical factors by means of the cataphorisis, electron-diffraction and other methods. The following fact was recognized from these experiments. When iron ore was pulverized and mixed with water, some colloidal substances were produced, of which γ-Fe2O3·H2O was most effective in binding the particles in to green pellets.View full abstractDownload PDF (807K) -
Yûnoshin Imai, Hikotarô Imai1953 Volume 17 Issue 3 Pages 129-134
Published: 1953
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThis paper describes the results of mechanical tests on several series of low-carbon (0.05∼0.08%), low-alloy (0.3∼0.5% Mo) steels containing boron (0.003%), tested in a normalized condition. The max. stresses and yield stresses are improved markedly by addition of boron, that is the former is raised from 40 kg/mm2 to 60 kg/mm2, and the latter, from 20 kg/mm2 to 40∼50 kg/mm2. In spite of such a remarkable increase of its strength, the toughness and ductility are not affected so much, only the elongation is decreased from 40% to the degree of 25∼27% and indicated local contractions distinctly. The desirable effects, mentioned above, are obtained only when the steels are deoxidized and denitrogenized with the required amount of Ti (0.05∼0.2%) or Al (0.1∼0.2%), prior to the addition of brone. The addition of Mn or Cr, to the degree of 1.0%, to these steels is very effective, and the max. stress and the yield stress are increased remarkably. Also, an increase of carbon-cotents up to the degree of 0.15% is very effective, similar to Mn or Cr-addition, but an increase of carbon-content results in a sharp decrease of toughness and ductility. Therefore, it is desirable that the carbon-content of these types of steels is limited under 0.2%.View full abstractDownload PDF (853K) -
Yûnoshin Imai, Hikotarô Imai1953 Volume 17 Issue 3 Pages 134-139
Published: 1953
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThis paper describes the results of mechanical tests on several series of low-carbon (0.05∼0.08%), low-alloy (0.3∼0.5% Mo) steels containing boron (0.003%), tested in a hardened-tempered condition. Like the results of tests under normalized condition, in a 550°-tempered condition, the mechanical properties of these types of steels are improved markedly by addition of boron, the max. stress rising from 55 kg/mm2 to 75∼85 kg/mm2 and the yield stress, from 40 kg/mm2 to 70∼80 kg/mm2. The reduction of area or impact values are not effected so much; the former remaining at 55∼65% and the latter showing the considerably high values of 7.5∼12.0 kg·m/cm2. The elongation is slightly decreased from 30% to 20∼25%. An addition of Mn or Cr, in the order of 1.0% or an increase of carbon-content up to 0.2%, are very effective to raise their strength much as in samples prepared under normalized condition.View full abstractDownload PDF (820K) -
Shigeyasu Koda, Eiji Isono1953 Volume 17 Issue 3 Pages 140-144
Published: 1953
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESS(1) As given in Part I of our report, we obtained a copper-chromium wire with a conductivity of 86%, a tensile strength of 62 kg/mm2 and an elongation of 2% by the following process-quenching, drawing, tempering and drawing again. (2) In this report, we describe how, to obtain better properties, we prepared wire rods with 0.86% of chromium, and quenched them, cold-drawn, tempered, cold-drawn and tempered again under several different conditions. (3) As the results of this research, we could obtain a wire with a conductivity of 80∼82%, a tensile strength of 65∼67 kg/mm2 and an elongation of 4∼6%.View full abstractDownload PDF (672K) -
Saburo Murai, Hidemi Sako1953 Volume 17 Issue 3 Pages 144-148
Published: 1953
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMany results were reported on the martensite transformation Al-bronze, but the theories on the mechanism of this transformation are not yet satisfactorily established. For this reason, to treat the problem of this momentary transformation in a fundamental manner, the writers have considered the factors that govern this transformation. In the present work, phenomena and mechanism of its transformation were re-examined not only by means X-ray analysis, photomicrostructure and specific gravity methods but also by an instantaneous measuring apparatus consisting of a set of magnetic ocillograph and amplifier devised newly. From the results obtained, it was ascertained that martensite transformation of this alloys is necessarily followed by a shear mechanism to some extent and that the process of martensite formation progresses in certain colony at a velocity of 10−2∼10−3 second.View full abstractDownload PDF (958K) -
Yoshihiro Hisamatsu, Masayoshi Kanno1953 Volume 17 Issue 3 Pages 149-152
Published: 1953
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe local cell polarization curves of mild steel in 10 percent sulfuric acid with and without inhibitor at the temperature 40° have been measured and presented by two indirect methods. The first is by the corrosion rate when a current from external source is applied, and the second is by the mixed potential and the breaks of the polarization curves when the external current is applied. Used inhibitors were mainly 0.5 percent diethylaniline. And it is shown, that the corrosion of steel under such conditions is controlled by both the anodic and cathodic polarizations of the local cell, the former being greater, and that the inhibitor affects both the anodic and cathodic polarizations of the local cell, the former being more strongly affected. This may be reasonably generalized to apply to many other organic inhibitors because most of them make the mixed potential nobler while the open circuit potential of the local anode is scarcely affected.View full abstractDownload PDF (732K) -
Toshihiko Okamura, Takashi Kimura1953 Volume 17 Issue 3 Pages 153-156
Published: 1953
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe imitation gold, which has been investigated by the authors, has the defect of tarnishing by the perspiration in practical use. The present investigation has been carried out on the tarnish-resistance properties of copper alloys by the measurement of the tarnishing rate and by the observation of the colours produced by tarnishing, using salt, lactic acid, urea and sodium sulphide as experimental reagents. In binary copper alloys, the tarnish-resistance to salt is improved by adding zinc, against lactic acid nickel and silver are effective, and α+β phase alloy of copper-zinc system is also good. No remarkable effects are obtained in the case of sodium sulphide particularly, neverthless it is full of interest that the tarnish-resistance property is improved by nickel, in spite of its weakness against sulphide. The tarnishing by urea is negligible. Oxide films, produced by selective oxidation of aluminium copper-aluminium alloys, are highly protective against tarnishing.View full abstractDownload PDF (665K)
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