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Volume 18, Issue 3
Displaying 1-15 of 15 articles from this issue
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Susumu Kawakami1954 Volume 18 Issue 3 Pages 141-145
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn this paper, the kinetic method was applied to explain quantitatively the thermal diffusion phenomena of molten alloys. The thermal diffusion flow of solute molecule in a binary system can be calculated from the difference of probabilities of migration in the hot and the cold parts respectively. Thus, the heat of transport ε* can be derived in the following formula: & ε^*=Soret coefficient ×RT^2........................ \labele1
& ε^*=ε_d-ε_h\ otagwhere εd and εh are the energy of inhibition at the original position and that of hole formation at the final position of the migrating molecule respectively. To calculate the value of ε*, the Soret coefficient must be determined from experiment. For a dilute solution it may be calculated by the equation Soret coefficient=\fracΔN_sN_oτ........................ \labele2as shown in the previous report by using temperature difference given to the system τ, initial concentration No, and concentration difference at Soret equilibrium ΔNs. If possible, it is desirable that the differential Soret coefficient is obtained. This value can be acquired by the interpolation method. As regards systems satisfying the equation of rate of first order reaction for that of thermal diffusion, the experimental determination becomes very easy. The value of ΔNs required for calculating the Soret coefficient can be represented in the following simple equation when the time ratio t2⁄t1 is chosen experimentally to be 2 in the primary stage regarded as first order reaction, ΔN_s=\frac(ΔN_1)^22ΔN_1-ΔN_2........................ \labele3where ΔN1 and ΔN2 are the concentration difference at time t1 and t2 respectively. As mentioned above, the heat of transport can be determined experimentally from Eq. (1), (2), and (3).View full abstractDownload PDF (687K) -
Yuzo Nakamura1954 Volume 18 Issue 3 Pages 145-149
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn account is given of a method of determining orientations in single crystals and polycrystals of aluminium by etch-pits, by which a stereograph can be directly and simply drawn with tolerable accuracy and it is easy to construct the pole figures by using triangular etch-pits. In this method, an accurately constructed model of unit cell having long axes which correspond to ⟨111⟩ and ⟨100⟩ directions is just inserted into the required triangular hole on a celluloid sheet mounted on a hanging horizontal table and so that the upper spotlight projects the poles of the axes on the lower paper board, the pole figures being thus obtained. Further, the pole figures of a grain with rectangular etch-pits can be constructed by measuring the angle between the slip line and the side line of the etch-pit and using some graphs. It has been ascertained that the pole figures prepared by this method agree well with those produced from results obtained by X-ray analysis.View full abstractDownload PDF (752K) -
Isao Gokyu, Hisashi Suzuki, Fumio Seki1954 Volume 18 Issue 3 Pages 149-153
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe textures for cold-rolled and annealed commercially pure titanium may have never been reported, for all the informations on iodide titanium. Here preferred orientations developed in this material are, in detail, investigated and are compared with the results already shown. The experimental results obtained in five specimens having different reductions are a little differnt from those in iodide titanium, as follows: (1) Cold-rolled texture is such shown 25∼30° rotated {0002}⟨10\bar10⟩ texture about the axis of rolling direction. In the basal plane pole figure, there develops the texture like that from compression, spread approximately 15° and 25∼30° about the rolling and the cross direction respectively. These textures are mainly explained by the twinned orientations of the first order. (2) Annealing texture at less than 600° retains the cold-rolled texture, and at 700° shows a component explained by the cold-rolled and recrystalized one already noticed in the cold-rolled. Recrystalized texture is shown by aproximately 25° rotation of {0002}⟨11\bar20⟩ texture about the axis bfore mentioned and is clearly described by a 30° rotation about the ⟨0002⟩ direction held with cold-rolled texture. Recrystalized and its basal plane double texture become more pronounced the higher the reduction and the annealing temperature. The recrystalized texture is the same as the high temperature anneled, even after the transformation.View full abstractDownload PDF (929K) -
Etsujiro Yajima, Koichi Furusawa1954 Volume 18 Issue 3 Pages 153-158
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe brittleness of steel at high temperature is very important for forging or hot working of steel. We dertermined the elongation of various carbon steels between 700° and 1050° and from these results we discussed the brittleness of steel at high temperature. All the samples of steel except the Armco iron showed two kinds of brittleness in the experimental temperature range. The first appears over the A1 transformation point. The reason seems to be in the coexistence of the two solid solutions α and γ. The second brittleness appears at a higher temperature and the minimun elongation occurs at about 850°. This is probably caused by the recrystallization of austenite and precipitation Al nitrides.View full abstractDownload PDF (1216K) -
Masuo Kawakami, Noboru Komuro1954 Volume 18 Issue 3 Pages 158-163
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTown gases in Japan, in general, have such a composition (%) as follows: CO 7∼12, CH4 16∼20, CmHn 2∼3, H2 30∼36, CO2 2∼6, H2O 0.5∼2, N2 28∼31. Of these components, the oxydizing ones, CO2 and H2O, are severely obstructive to the carburizing activity of CO, CH4 or CmHn. In order to minimize the obstruction, it has been usual to employ the method of reducing them with charcoal. In our investigation, it was found that the reducing power of charcoal is promoted by adding carbonates of alkaline or alkaline-earth metals, especially BaCO3. This is also recommended from the stand point of economics. Applying these results, we succeededin realizing carburization of gas produced in many kinds of steel works.View full abstractDownload PDF (869K) -
Isamu Igarashi, Yo Serita1954 Volume 18 Issue 3 Pages 163-165
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSpecimens were prepared as 4.1% C, 0.3 % di ferro-alloys by chill-casting. These were heated of various temperatures and for various hours, and their microscopic structures were examined. Cementite precipitated specklike or granular in dendritic austenite during annealing at above A1 temperature, and they coalesced with increased annealing time. At last, in austenite some coalesced large cementite grained in austenite which are difficult to graphitze like the eutectic cementite in chill-castings. While cooling the graphitized specimens, the primary precipitated cementite will be swiftly graphitized even by furnace-cooljng. So, it may be considered that there are some differences between coalesced or eutectic cementite and primary precipitated cementite.View full abstractDownload PDF (625K) -
Yoshitsugu Mishima1954 Volume 18 Issue 3 Pages 165-169
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTo measure the hardness at grain boundary region and at the central part of grain seperately has been successfully carried out by the author during the process of precipitation in Al-Ag alloy, using improved Vickers micro-hardness tester (load used was 25 g). It is easily understood that the grain boundary region is harder than the interior as deformation caused by the indentation will be interfered near the grain boundary. When aging proceeds, hardening can be thought to occur faster at the grain boundary region because diffusion must be more rapid near the grain boundary. These facts were confirmed in this report as shown in Fig. 1 and 2. However, as precipitation goes on, a state of maximum hardness will be attained, then softening must follow if further aging is to proceed. As the changes occur earlier near the grain boundary, softening, too, will be early to occur at the region and so, the hardness will become lower there than that of the interior when softening proceeds to some extent. This time this fact, have been clearly observed which, the author believes, is important in the study of aging process, as it proves that aging proceeds faster near the grain boundary. The process of precipitation; general precipitation, growth of the preceipitates into Widmanstätten figure and grain boundary reaction, was also observed microscopically at 200° and 300°, as shown in Photo. 1∼16, taken through a photgraphic apparatus attached to the micro-hardness tester. The re-solution of the precitpitate and its re-precipitation within the recrystallized new grain were also observed and the mechanism of the phenomenon was discussed to some extent.View full abstractDownload PDF (1210K) -
Kyuya Nagasaki1954 Volume 18 Issue 3 Pages 170-172
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe changes in structure during the isothermal transformation at the temperature of 500° and 400° for 4.75%, 4.97%, and 5.50% Si-Cu alloys quenched from 800° were tested microscopically. The transformation proceed very slowly from the initial state, α for 4.75% and 4.97% Si-Cu alloys and α+κ for 5.50% Si-Cu alloy, to the most stable equilibrium state α+γ through the meta-stable equilibrium state between α and κ, as shown in Fig. I extending the boundary lines α⁄α+κ and α+κ⁄κ to the lower ranges of temperature. It was considered that the slow phase change of α to κ on quenching into a region of temperature of about 400° where it whould be stable as κ, i.e., beneath the extension of the line α+κ⁄κ, is of diffusionless “nucleation and growth” type.View full abstractDownload PDF (732K) -
Rihei Kawachi1954 Volume 18 Issue 3 Pages 173-176
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSExperiment was carried out about the effects of preheating on the annealing characteristics of final product of 24S type alloys with or without Mn (and Cr). In the case of alloys with Mn or Cr preheating of ingot reduces softening temperature and improves the ductility in annealed state. However, of the alloys without Mn and Cr preheating has no such effects, the ductility of annealed sheets being very good even in unpreheated samples. These beneficial effects of preheating may be due to the reduction of Mn content in α phase.View full abstractDownload PDF (682K) -
Riei Ichikawa1954 Volume 18 Issue 3 Pages 177-180
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCoarsening of recrystallized grain is recognized in Mg, as in other metals, which is severely deformed and annealed at higher temperature. The effect of kind and quantity of alloying elements upon the grain coarsening in Mg alloys was researehed. Ten kinds of alloys having some components whith were in the range of α-solid solution were severely compressed (about 50∼60%) at 250° and annealed at various temperatures, and the ranges of the component and the temperature of coarsening were measured. In such alloys having a rich solubility range of α-solid solution as Mg-Pb and Mg-Cd, the coarsening happened in a wide range of alloying component, but in those having poor solubility as Mg-Cu, Mg-Ca and Mg-Mn, the coarsening did not happen. In such alloys having a solubility between the above two as Mg-Al, Mg-Sn, Mg-Ag, Mg-Bi and Mg-Zn, the coarsening accurred for a smaller range of component than that of Mg-Pb and Mg-Cd. The lowest temperature of coarsening was 480° in annealing for 24 hours. There were two orientations of the coarsened grains, the one, [11\bar20] which was nearly paralled to the direction of deformation and the other, [0001] which was inclined about 30∼65° to the working direction.View full abstractDownload PDF (767K) -
Goro Itoh1954 Volume 18 Issue 3 Pages 181-184
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe mechanism of cathodic protection was studied with aluminium alloys, containing copper, in 3% NaCl aqueous solution. For this purpose, a model experiment was made using an aluminium-NaCl2 couple as a model of corrosion cell in aluminium alloy. When external electric potential for cathodic protection is applied to an Al-CuAl2 couple, the corrosion current decreases in the rate of inverse proportion to the external potential. On the other hand, the current flowing from the liquid into the cathode (CuAl2) remains the same, until the corrosion current becomes zero. Therefore, the actual cathodic polarization curve is invariable and independent of the external current, till the cathodic current increases to such a heighr as to suppress the corrosion of anode. In order to assure complete protection, the cathodic current must be applied proportionally to the cathode area, but the polarized potential of the couple remains constant. To compare these model experiment with actual results with various alloys, the other experiment was made with an Sn-Zn couple as a model of their alloy, and with ordinary Sn-Zn (8.1%) alloy. The correlation was found satisfactory between these two cases of the model and of the alloy.View full abstractDownload PDF (690K) -
Tokutaro Hirone, Kazuo Kamigaki1954 Volume 18 Issue 3 Pages 185-188
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe attenuation of ultrasonic waves in chromium-molybdenum steel was measured for various frequencies from 2 to 25 megacycles per second. The method of measurement is similar with the two probe method used in the ultrasonic flaw detection of metals; The ultrasonic pulse is sent into the specimen by one of the crystals and the transmitted pulse is received by the other. The attenuation during the transmition is measred by a calibrated attenuator. The specimen is at first quenched from 1000°C and then annealed for one hour each at 100°, 200°, 300°, 400°, 500°, 600° and at last for five hours at 680°C, and the attenuation was measured at each successive stage of the heat treatment, the results being plotted in Fig. 3 as functions of frequency. The attenuation constant becomes smaller for martensitic structure (quenched specimen) than for pearlitic one. This tendency becomes more remarkable for troostite. Those characteristic changes of attenuation are illustrated qualitatively by considering the Rayleigh scattering of ultrasonic waves due to the metallographic structures of steels.View full abstractDownload PDF (1039K) -
Yoshizo Takeda1954 Volume 18 Issue 3 Pages 188-192
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe rectification characteristic of cuprous oxide rectifiers depends on various factors, especially on the purity of copper plates used as base metal. Copper plates including various kinds of inpurities were examined as cuprous oxide rectifier elements. The said impurities being S, Se, As, Sn, Bi, Sb, Cd, Zn, Ni, Fe, Al, Ag, Au, Pb, O, Mg, P, Tl and Si. In this report, cuprous oxide rectifier elements which were contaminated with S, Se, As, Sn and Bi were studied. The following results have been obtaind: (1) When copper plates contain S from 0.0016% to 0.014%, the resistance in the foward direction scarcely increases, and is almost unaffected in the reverse direction except by the one containing 0.014% S. In general S contents in copper plates exert small influences. (2) Within creasing Se content from 0.000% to 0.05%, the resistance decreases in both directions, therefore Se contamination is more injurious to the characteristics in the reverse direction. When copper contains over 0.05% Se, the oxide layers scale off with nonadherence. (3) When as content in copper varies from 0.0016% to 0.041%, the resistance in the forward direction increases, but decreases in the reverse. (4) When Sn content varies from 0.000% to 0.04%, the reverse resistance decreases, but the forward increases a little more than to 0.04%, in the case of As. (5) The forward current increases when copper plate contains Bi from 0.000% and the reverse current, too.View full abstractDownload PDF (584K) -
Kazuo Hori1954 Volume 18 Issue 3 Pages 192-196
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of some factors resulting from the differences in melting conditions and the differences of casting conditions were studied in our former reports and now, the effects of holding time at max. melting temp. have heen nstudied and inspected with reference to the results of the macrostructure of specimens, crystal the grain sizes and specific gravities. The results obtained were as follows: (1) It was recognized that the effects of holding time on runnability were in close mutual relation with the temperature urder which the molten metals were held. (2) The effects of holding time on running velocity did not always serve in controling the length of runnability. These depended on the holding time insh ort holding but in long holding, the running velocity did not always determine the runnability. (3) In the measurements of crystal grain sizes, the effects of holding time were clearly recognized with effects of max. melting temperature. (4) The differences of specific gravities based on the different holding time and max. melting temp. were clearly recognized and these effects were larger in long holding and at high temperature.View full abstractDownload PDF (687K) -
Harumichi Kawasaki1954 Volume 18 Issue 3 Pages 196-197
Published: 1954
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSGenerally, gunmetal include Cu, Zn, Sn, Fe, Al, Ni, Mn. (1) Dissolve sample with mineral acid and dilute with the water, then Sn is removed as H2SnO3. (2) Cu and Mn are removed by electrolysis as Cu and MnO2 (use mineral acid solution and Pt electrodes. (3) Neutralize the solution with NH4OH and organic acid, then Fe is removed as Fe(OH)3. (4) Only Zn is electrolysed from organic acid solution on a Cu cathode (5) Al and Ni are not electrolysed from acidic solution.View full abstractDownload PDF (195K)
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