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Volume 19, Issue 5
Displaying 1-15 of 15 articles from this issue
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Susumu Oki, Ren Obata1955 Volume 19 Issue 5 Pages 303-306
Published: 1955
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStudies were made on solidification and cooling of sand mould castings of various shapes by temperature measurements and pour-out tests. W-Fe and W-Mo thermocouples were used for the temperature measurement, as they were more convenient and economical than Pt/Pt-Rh thermocopules to use for the work of this kind. Results obtained were summarized as follows: (1) The rate of skin formation at the early stage of solidification of cylindrical steel castings, with and without chills, was determined by pour out tests. (2) Many cooling curves were obtained at the centres and the surfaces of cylinders of various diameters. In the whole range of diameter of the steel castings, the metal surface instantly cooled to 1350°∼1400° and was kept in this temperature range until freezing of the centre began. (3) The cooling curves obtained at the centres of risers and the casting surfaces of some rollingstock parts showed that the thin part next to a heavy section, such as a spoke of a locomotive driving wheel casting, cooled irregularly due to thermal influence of the heavy section. (4) The surface temperature of a core set near the centre of a large mass of cast steel such as the boss of a wheel casting was found to rise gradually from 1350° to the liquidus temperature. This temperature rise was considered to be a cause of secondary metal penetration into the mould.View full abstractDownload PDF (679K) -
Tadamichi Takei1955 Volume 19 Issue 5 Pages 306-309
Published: 1955
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA spectrographic method was studied for determining the local concentrations of copper and nickel enriched in the surface layer of steel heated in oxidizing atmosphere. This method employs a Feussner spark between the sample surface and the upper counter electrode of graphite with flat top and rounded edge, and the successive determinations were carried out each time after polishing away the sample surface by 0.03 mm, each of them comprising four different exposure times to secure high precision. Moreover, Seidel’s transformation was used to compute the nickel concentration, and the working curves were made for each plate to eliminate the long period variation of sparking condition. It was impossible to obtain chemical results in the enriched layer comparable with those of spectrographic analysis,while the chemical results for the average concentrations of the sample agreed with the spectrographic results at a position 0.2 mm or more deep from the surface.View full abstractDownload PDF (693K) -
Yoshiaki Miura1955 Volume 19 Issue 5 Pages 310-313
Published: 1955
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESS(1) For the determination of iron in zinc pot samples, the sample was dissolved in nitric acid, neutralized with sodium hydroxide and analysed polarographically in a supporting electrolyte consisting of 1 mol-sodium acetate and 0.05 mol-E.D.T.A. (Complexone). According to this method, iron can be determined in 17 min without any interference. In the case of aluminium, Willard and Dean method was applied after removing the interfering ions by electrolysis with magnetic mercury cathode. The time required for Al analysis is about one hour. (2) The determination of both elements in coatings was carried out by sealing the section of sheet with paraffin, dissolving in hydrochloric and perchloric acid mixture and then treating the sample solution in the same manner as in the case of pot samples. (3) To avoid the effect of segregation, the sample of zinc-coated sheets should be taken perpendicular to the rolling direction of the sheet. (4) Appearance of blackish colloidal precipitation was observed during electrolytic separation and the precipitation was found to be platinum originated from the anode and to have no interference with the determination of aluminium. (5) The waste mercury used in the electrolytic separation can be purified simply by treating with concentrated hydrochloric acid.View full abstractDownload PDF (778K) -
Hidehiro Gotô, Shurô Takeyama1955 Volume 19 Issue 5 Pages 314-317
Published: 1955
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe study was carried out to establish the method for the determination of Ti2+, Ti3+, metallic aluminium and total amounts of aluminium and chlorine in the reaction products of titanium tetrachloride with metallic aluminium. The amounts of Ti2+ and Ti3+ were determined by dissolving the sample with ferric sulfate solution and water, and titrating each solution with potassium permanganate or ferric solution. The total amounts of aluminium was determined with oxine after the separation of titanium with sodroxide, and chlorine was determined by the usual gravimetric method as silver chloride. The metallic aluminium content was estimated from the residue obtained by dissolving the sample in water, by gravimetric or volumetric method.View full abstractDownload PDF (684K) -
S. Kachi1955 Volume 19 Issue 5 Pages 318-322
Published: 1955
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe thermodynamic properties of the intermediate compound AgMg were studied by the electrochemical technique using a galvanic cell AgMg|Mg++ ion in (LiCl-KCl)|Mg. The electromotive force E of this cell, as a function of the degree of disorder α, can be well defined by the equation derived by Wagner and Schottoky as follows;
(This article is not displayable. Please see full text pdf.)
\ oindentwhere E0.5 is the electromotive force of the stoichiometric compound AgMg, Δx the excess or deficit mol fraction relative to 1:1 composition, ℑ the Faraday constant, and Z is the valence of the conducting ions in the electrolyte. The degree of disorder α is shown to be of the magnititude of 10−4 at 400° to 500°, which is very small compared with the values for other intermetallic compounds. The stability of this ordered structure up to the melting point is discussed from thermodynamical standpoints.View full abstractDownload PDF (784K) -
Susumu Kawakami1955 Volume 19 Issue 5 Pages 322-325
Published: 1955
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe fundamental quantities in Soret effect for molten alloys can be determined from the thermal diffusion data as follows. As the equation of the first order reaction rate d(Δn)⁄dt=k(Δns−Δn) where the rate constant k is equated to π2D⁄a2 is satisfied well at the primary stage of separation in the case of Pb or Cd dilute solutions, the ordinary diffusion constants and at the same time, from their temperature dependence, the activation energies can be obtained experimentally from k measurements. Their magnitudes lie respectively between 2.4×10−5∼5.1×10−5 cm2/sec and 4.4∼5.6 kcal/mol for Pb-Sn and 2.5×10−5∼5.2×10−5 cm2/sec and 4.7∼6.0 kcal/mol for Cd-Sn. It is proved that, considering the nature of measurements, the above values are reasonably close to those by other methods. The thermal diffusion constants are obtained by multiplying the Soret coefficients by the ordinary diffusion constants.As the latter are estimated to be 5.8×10−4∼2.2×10−3 deg−1 for Pb-Sn and 5.6×10−4∼1.9×10−3 deg−1 for Cd-Sn from the experimental determination, the former amount to 2.4×10−8∼8.6×10−8 cm2/sec·deg. for Pb-Sn and 2.5×10−8∼8.8×10−8 cm2/sec·deg. for Cd-Sn respectively.View full abstractDownload PDF (649K) -
S. Takeuchi, K. Furukawa1955 Volume 19 Issue 5 Pages 326-329
Published: 1955
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt is known that magnetite crystals contain excess oxygen over the stoichiometric composition Fe3O4 by oxidation, and the oxygen content depends on the oxygen pressure in atmosphere and the temperature. The Fe3O4 crystal structure of the inversed spinel type, in which O ions occupy the close packed cubic lattice points, and the 8f lattice sites of its unit cell are occupied by 8 tetrahedral Fe+++ ions, the 16C lattice sites by octahedral 8Fe+++ and 8Fe++ ions statistically. When the magnetite crystal of such a structure contains excess oxygen by oxidation under an oxidizing atmosphere, it can be assumed that a vacant site accompanying two electron defects resulting in two Fe+++ ions is found on the octahedral iron-ion lattice point. Under these circumstances we can calulate the partition function of magnetite phase, from which the equilbrium relation between the oxygen content in magnetite, the partial pressure of oxygen in atmosphere, and the temperature is deduced theoretically. These theoretical results are in good agreement with observations by Greig et al. and Darken and Gurry.View full abstractDownload PDF (653K) -
Hikozô Endô, Namio Ohtani1955 Volume 19 Issue 5 Pages 329-332
Published: 1955
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe authors have investigated the effect of dissolved oxygen and H2O2 in alkaline solutions upon contact corrosion loss ΔW of zinc, in a zinc-mild steel corrosion couple. Considering oxygen electrode reaction, we have derived a formula of ΔW, k and concentration C of H2O2, which shows that the smaller the value of k and the electric resistance of the solutions, the larger is the value of \left|\dfrac∂ΔW∂k\ ight|, and have interpreted the observed effect by calculating the extent of change of ΔW, in the case of k taking a value according to the amount of dissolved oxygen or H2O2. ΔW increases by adding a small amount of H2O2 and shows a decline as the dissolved oxygen decreases. The reason why ΔW increases is, it appears, in the case of pH 7, mainly due to the depolarization of cathode effected by the dissolved oxygen or H2O2, and in the case of pH 12.5, due to the fact that the corrosion product Zn(OH)2 changes into a soluble substance HZnO2− or ZnO2−− and both the electrodes depolarize.View full abstractDownload PDF (587K) -
Isao Gokyû, Hisashi Suzuki, Kakunosuke Yamamori1955 Volume 19 Issue 5 Pages 333-335
Published: 1955
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe drawing textures in cadmium and zinc crystals, which belong to h.c.p. metals having the axial ratio of more than 1.633 were studied at various reductions. The observed experimental results were summarized as follows: (1) Both metals have the same drawing texture. (2) This texture is generally double-cone-fibered or spiral-fibered, and the preferred direction is in coincidence with the hexagonal axis. (3) But a single-cone-fibered texture is also observed near the surface. (4) The inclination of the basal plane to the fiber axis is, regardless of reductions, approximately 30° in double-cone-fibered, and approximately 20° in single-cone-fibered textures.View full abstractDownload PDF (596K) -
Tomo-o Sato, Hideo Kaneko, Taiji Nishizawa1955 Volume 19 Issue 5 Pages 336-340
Published: 1955
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe present paper deals with the research on the electrolytic isolation of carbide from plain carbon steel by means of a hydrochloric acid cell, in order to determine the qunantitativeness of this procedure, and to provide a general preliminary test to our further experiments. The results obtained are as follows. (1) Hydrochloric acid cells are applicable to the investigation of carbide isolation from carbon steel with a satisfactory performance, although a small amount of carbide is decomposed. (2) The suitable conditions are as follows: (a) The current density should be 5∼30 mA/cm2 according to the microstructure of specimen, (b) 0.5 N hydrochloric acid and 0.2 N hydrochloric acid+5% citric acid solutions give good results as the electroyte, and (c) the maintenance of a reducing atmosphere by hydrogen is necessary. (3) Several electron micrographs of various forms of cementite isolated from carbon steel having different structures are shown. (4) In the case of hardened steel, carbon in martensite is not ionized during electrolysis, but is either retained as amorphous carbon or removed as hydrocarbon gas. For resolving these difficulties, further experiments must be carried out.View full abstractDownload PDF (837K) -
S. Kachi1955 Volume 19 Issue 5 Pages 340-343
Published: 1955
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe precipitation of graphite during annealing of white cast-iron at the temperature range of 950° to 1100° was microscopically observed. It was shown that graphite mainly forms at the grain boundaries of austenite, austenite-cementite interfaces, or the surfaces of non-metallic inclusions. This structure sensitive nature of graphitization can be well explained by the impossibility of direct decomposition of cementite and the thermodynamic properties of austenite. The driving force of graphitization is only about 20∼150 cal at the temperature of the experiments, and is quite small compared with that of the other transformations of metals. Therefore, it may be considered that interstitial carbon has a tendency to precipitate at the place of minimum activation energy for the nucleation, say, at grain boundaries or interfaces. By this mechanisms, Fe atoms need not migrate to give a volume to the small nucleus of graphite. This interpretation get a strong support from the fact that carbon atoms in austenite mutually exert a repulsive force. Otherwise, cohesion of mutually repulsive carbon atoms is very curious. In fact the activation energy of graphitization is nearly equal to that of diffusion of carbon in austenite, and this shows the unnessessity of migration of Fe atoms for the nucleation of carbon.View full abstractDownload PDF (917K) -
Jun Kuroyanagi, Hiroshi Hirotani1955 Volume 19 Issue 5 Pages 343-346
Published: 1955
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe cause of hardening of 0.9% carbon steel due to over-heating was studied by means of electron microscope and the following results were obtained. (1) In the over-heated state, the grain boundaries have not been found more broadened than in the standard state, indisagreement with the results of experiments of Radovich. (2) In the hardened state, we could not find the segregation of precipitations in the grain boundaries. On the contrary, we found the segregation of precipitations in the ferrite texture.View full abstractDownload PDF (987K) -
Katsumi Okada, Nobuo Kawashima1955 Volume 19 Issue 5 Pages 346-350
Published: 1955
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt has been found that cluster slips, uniform slips with deformation bands, or other slips would be formed by the different orientation of crystals. In the triangle of the stereographic projection, cluster slips are formed in the crystals ⟨111⟩ and uniform slips near the crystals ⟨110⟩ in the triangle. Much investigations on the rotation axis of a uniform slip in extended crystals have been reported, but few of them examined the crystals nearest to ⟨111⟩. In the present report, the rotation axes of cluster slips in the crystals oriented nearest to ⟨111⟩ were determined by the new X-ray Laue technique. There are two rotation axes in the crystals ⟨111⟩: the one is ⟨121⟩ which is normal to the slip direction on the primary slip plane, and the other is ⟨111⟩ which is normal to the primary slip plane. The rotation of ⟨121⟩ is responsible for kink bands in the cluster slip region, while the rotation of ⟨111⟩ seems to be responsible for the screw dislocations.View full abstractDownload PDF (809K) -
[in Japanese]1955 Volume 19 Issue 5 Pages A79-A84
Published: May 20, 1955
Released on J-STAGE: November 11, 2008
JOURNAL FREE ACCESSDownload PDF (564K) -
[in Japanese]1955 Volume 19 Issue 5 Pages A84-A87
Published: May 20, 1955
Released on J-STAGE: November 11, 2008
JOURNAL FREE ACCESSDownload PDF (1586K)
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