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Volume 21, Issue 12
Displaying 1-15 of 15 articles from this issue
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Taro Ohtsuki1957 Volume 21 Issue 12 Pages 683-685
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESS(1) The gas evolved from copper manufactured by deoxidizing with carbon and still containing 0.2% of oxygen consists largely of CO2 with smaller H2, CO and H2O at the temperature 720∼945° and the evolving energy of CO2 is 11.5 kcal/mol. The evolution depends on the chemical reaction of 2Cu2O+C\ ightleftarrowsCO2+4Cu at the interface. (2) Measuring the evolution of H2O from copper whose evolved gas consists mainly of H2O, and in which the oxygen content is 0.2% ,it was found that at the temperature 730∼920°, in the earlier stage the evol ing energy is 10 kcal/mol and the evolution depends on the chemical reaction of Cu2O+H2\ ightleftarrowsH2O+2Cu at the interface. In the later stage the evolving energy is 45 kcal/mol.View full abstractDownload PDF (345K) -
Takuichi Morinaga, Shigeo Zaima, Tsuneo Takahashi1957 Volume 21 Issue 12 Pages 685-689
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (586K) -
Kyôji Tachikawa1957 Volume 21 Issue 12 Pages 689-693
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe changes of the magnetic properties and the microstru ture of high-C high-Cr magnet steel by various heat treatments were investigated, and the origin of the permanent mag etism o this steel was studied. The best magnetic properties (B∼7000 G, Hc∼140 Oe and (BH)max∼0.4×10) are obtained after primary heating and subsequent air-cooling from 1060°. During air-cooling from 1060° many fine spherical carbides which are about 2000 Å in diameter precipitate in the martensite. By primary heating at 600∼900° follow d by air-cooling from 1060°, the quantity of the retained austenite is decreased and the precipitation of the fine carbides promoted. In the case of oil-or water-quenched specimens, dispersion of the fine carbides is supressed. Both Hc and Br of the specimen are increased, whereas the hardness is decreased by the precipitation of the fine spherical carbides. The coercive force of this steel is due to the internal stress in the martensite and also to the magnetization fluctuation of the martensite caused by the precipitation of many fine carbides.View full abstractDownload PDF (917K) -
Nobuteru Awa1957 Volume 21 Issue 12 Pages 693-696
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe plating degree and the current efficie cy are var d in conti uous and intermittent plating process. The value of the plating degree as well as the c rrent e iciency usually diminishes with the lapse of time, unless the bath voltage is controlled at the outset of the experiment below a certain bath voltage, that is below the decomposition voltage in most cases. The report deals with the case of a plating bath of low concentration at the temperature of 45° and 2.2 volt. The results showed that the plating under suc conditions, continued for a period of time would make the surface of the anode. Changeless and eventually produce a state where no variation of the voltage and the current is obs rvable.View full abstractDownload PDF (465K) -
Takuro Saga, Kinji Sato1957 Volume 21 Issue 12 Pages 697-699
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEquations to determine the residual stress distribution in composite materials are introduced by expanding the customary equation for beams or strips. As the specimens are removed mechanically or chemically, their curvatures are changed by the action of the residual stress. The stress distribution can be determined by removing the successive layer from the surface and measuring the resulting curvature. As the explicit function of them the stress is presented for general cases, besides practical examples are given, so the equations will be of practical value in many cases.View full abstractDownload PDF (321K) -
Fumitaka Yoshikawa1957 Volume 21 Issue 12 Pages 699-703
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn this report, samples of pure iron were carbonitrided under various conditions by using C2H6,NH3, and H2 gas mixtures, and the changes near the starting temperature of austenitization were measured by means of differential thermal dilatation, X-ray diff action, micro-Vicker’s hardness, and chemical analysis tests. The results in summary were as follows : (1) The double-staged contraction beginning at 590∼605° and 620∼650° is du to γ-generation. The transition b gins with the first stage. (2) Layers of compounds of high-N low-C ε+γ′ and high-N high-C θ+ε+γ′ were found, usually in large thich ess. (3) The cause of lowered surfacial hardness and scattering of the measured values in the hardness distribution curve of anncealed specimens lies mainly in the existence of irregular black spots formed by change in concentration during cooling. (4) A radical revision of the experimental method was felt desirable for assuring better accuracy.View full abstractDownload PDF (798K) -
H. Orii, A. Ono, K. Sumino, S. Sakui1957 Volume 21 Issue 12 Pages 703-707
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInformations on the temperature change of molten metal during die casting would play important part in explaining the various phenomena which are presented at die casting. But it is very difficult to record the rapid temperature change of molten metal during casting, because the molten metal solid fies within the very short time of 0.05∼0.07seconds after injection. We measured the temperature change of zinc alloy ZAC. No 1 during die casting by using a piano wire-constantan wire thermocouple, each of 0.1 mm diameter, and an electromagnetic oscillorgraph. The results obtained were as follows: (1) The molten me al injected through the gate is cooled about 25° by passing through the gate. (2) A chilled surface is formed in 0.03 seconds after the ar ival of metal at the cavity wall. The cavity is filled in 0.07 seconds after injection. So the molten metal flows through the spac surrounded by the shell of chilled surface, thus retaining the blow holes on the center line of the test piece. (3) The temperature difference of molten metal between the gate end and the opposite end of the cavity of the test piece decreases with the rise of die temperature. (4) We observed an instantaneous rise of temperature of molten metal at the end of injection.View full abstractDownload PDF (656K) -
K. Sumino, H. Orii, A. Ono, S. Sakui1957 Volume 21 Issue 12 Pages 707-711
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe change of pressure acting on the plunger during die casting was recorded by a wire strain gage bound on the plunger surface and an electromagnetic oscillograph. The displacement vs time curve of the plunger was also recorded by the same oscillogragh. The following results were obtained. (1) The pressure vs time curve had several peaks and plateaus. The plateau appeared during the period of filling the cavity with molten metal, while the peak indicate the end of filling up. (2) The pressures of plateaus and peaks increased with increasing pressure of the accumulator, though not in proportional ratio. (3) The tendencies of these curves varied with the different types of dies shown in Fig. 1 and Fig. 2 of our first report. Die II showed smoother a d lower peaks and plateaus than that of die I. This perhaps explains the superior mechanical properties of the test piece cast in die II.View full abstractDownload PDF (578K) -
Yôtarô Murakami, Hirozo Kimura, Yoshio Nishimura1957 Volume 21 Issue 12 Pages 712-716
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMicroscopic examination, melting point det rmination and X-ray analysis have been employed to construct the general outline of the constitutional diagram of the titanium-iron-carbon system. There exist two quasi-binary eutectic reactions as liquid\ ightleftharpoonsδ+TiFe2 and liquid\ ightleftharpoonsδ+(Fe)α in the ternary system, consequently, the equilibrium relationships therein can be divided into the three indipendent parts of TiC-Fe-C, TiC-Fe-TiFe2 and TiC-TiFe2Ti. In the region of TiC-Fe-C, there exist three non-variant reactions as follows:
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Tadayuki Nakayama1957 Volume 21 Issue 12 Pages 716-720
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe present author studied, by the electron transmission method, surface films of 8.86%Al-, 19.30%Al-, 28.60%Al-Fe alloys and calorized steel heated in air at high temperature (700° and 1000°), and thereby detected special protective layers which have not yet been found by the electron reflection method. A solution of iod ne in methanol was used satisfactorily for isolating surface oxide films from Fe-Al alloys. The present studies verified experimentally that fine Al2O3 (α-Al2O3 or γ-Al2O3) films besides α-Fe2O3 crystals, are formed on the surfaces of Fe-Al alloys and calorized steel oxidized in air at 700°. It was also clarified by electron diff action measurements that a compact α-Al2O3 film is mainly produced on the surface of 19.30%Al-Fe alloy, and moreover, that 28.60%Al-Fe alloy and calorized steel are covered with well grown γ-Al2O3 crystals at high temperature oxidation. These α-and γ-Al2O3 films retard not only the diffusion of Fe and Al atoms from inside to surface, but also the penetration of O2 towards inside, and therefore these films on Fe-Al alloys containing high % of Al and calorized steel are considered to have a good effect upon the resistance against for high temperature oxidation.View full abstractDownload PDF (689K) -
Toshio Doi1957 Volume 21 Issue 12 Pages 720-724
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSamples of copper alloys containing chromium up to 1.02% were prepared by vacuum melting and casting with which the author studied the effects of chromium addition upon the softening temperature and mechanical properties at elevated temperatures, furthermore the effects of quenching temperatures, aging conditions and chromium addition upon the age-hardening. The results of the experiments were as follows: (1) The softening temperature of pure copper was about 200°, but of 0.10%Cr-Cu it was about 300°, and of 0.29∼1.02%Cr-Cu it was at about 400°. (2) To obtain better properties, the quenching must be done at proper temperatures, as follwos:
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(3) The aging temperature to obtain the maximum hardness and tensile strength, when the alloys were aged 1 hour, were about 520° and 480°. (4) At elevated temperatures, the tensile strength of 0.29%Cr-Cu was 3 to 4 times as large as that of pure copper.View full abstractDownload PDF (661K) -
Effects of Cold Working on Precipitation in Age-hardenable Alloys (1st Report). On the Copper AlloysYôtarô Murakami, Osamu Kawano1957 Volume 21 Issue 12 Pages 724-728
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSExper ments have been carried out to examine the effects of cold-working on the rate of precipitation in binary polycrystalline Cu-Ti, Cu-Cr and Cu-Fe alloys by measurements of electrical resistance, microhardness and thermoelectromotive force. In Cu-Ti alloys (1.72%Ti), in which the existence of the intermediate phase in precipitation process was suggested from our previous experiments, the electrical resistance measurements provided evidence that at lower aging temperature (220°) the rate of precipitation of cold-worked specimens is less than that of unworked specimen, and that at higher temperature cold working accelerates the process. In either Cu-Cr alloys (0.30%Cr) or Cu-Fe alloys (1.29%Fe), such a suppressive effect of cold-working is found at lower aging temperature, too, although not so remarkable as in the Cu-Ti alloys. On the other hand, in copper of high purity, such an effect is not found. It is suggested that the rate of precipitation at lower temperature in cold-worked specimens is retarded by the stronger binding interaction between solute atoms and lattice defects, and this interaction effect is more remarkable in the Cu-Ti alloys. These results have been confirmed by the calculations of the interaction energies between solute atoms and dislocations.View full abstractDownload PDF (770K) -
Tunezô Saitô, Kazuo Maruya1957 Volume 21 Issue 12 Pages 728-732
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe self-diffusion coefficients of calcium in molten slags (CaO-SiO2, CaO-Al2O3, CaO-SiO2-Al2O3, and CaO-SiO2-Al2O3-MgO systems) have been measured by the method of semi-infinite medium at the temperature range from 1350° to 1600°. The diffusion coefficients were in the order of 10−6∼10−7 cm2 sec−1, and the activation energies were 40∼70 kcal/g·mol for all slags investigated. The results of ternary basic slags were expressed as follows:
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The diffusion coefficient has a good correspondence with both the specific electric conductivity and the viscosity coefficient. Some behaviors of Al2O3 and MgO in basic slags have been also discussed.View full abstractDownload PDF (691K) -
Mikio Yamamoto, Jirô Watanabé1957 Volume 21 Issue 12 Pages 732-736
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe light-figure phenomena have been observed with lead single crystals etched chemically with various reagents and the suitability of the obser ed light figures for determining crystal orientations and the crystal faces developed by etching have been examined. Distinct{100},{110} and {111} light figures, suitable for orientation determination, are produced by etching with concentrated nitric acid plus water (3:7), with concentrated nitric acid plus acetic acid an ydride plus water (3:5:12), or with acetic acid anhydride plus 40 percent hydroperoxide plus water (19:2:19). It has been found that the crystal faces developed by etching are, besides the{100},{110} and {111} faces developed commonly by short-time etching, the {994} faces due to the first reagent, the{720} faces due to the second, and the {210}, {552}, {922}, and {311} faces due to the last.View full abstractDownload PDF (852K) -
Namio Ohtani1957 Volume 21 Issue 12 Pages 736-739
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSupplementing the results described in the first report in which the corrosion current of eutectic binary alloy was analysed, the author interpreted the tendency of the variation of the corrosion rate of eutectic alloy in the case of cathodic control by the difference of hydrogen overpotentials η of component metals as follows : If ηA of a component A (base metal) is greater than ηC of a compo nent C (noble metal), that is, ηA>ηC, the corrosion rate of eutectic alloy would generally increase and have its maximum point, but if ηA<ηC, it would decrease rapidly.View full abstractDownload PDF (444K)
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