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Volume 31, Issue 9
Displaying 1-18 of 18 articles from this issue
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Toshio Izaki, Kôichi Arai1967 Volume 31 Issue 9 Pages 1023-1028
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe correlation between the pitting corrosion and the activating process of aluminium and its alloys has been investigated in Cl− containing borax buffer solutions with pH values of 5.5∼8.5. Effects of the critical activating potential, pH, concentration of Cl− and anodic polarization behavior on the pitting corrosion of aluminium are studied by means of potentiostatic electrolysis and the potentiodynamic method. The experimental results obtained are as follows.
(1) A critical activating potential exists in anodic polarization curves of aluminium. Near this potential, aluminium is rapidly activated and the anodic current density is increased.
(2) The critical activating potential is affected by the concentration of Cl− and the surface condition of aluminium and shifts toward the basic potential side in proportion to the concentration of Cl−. In case the aluminium oxide film is stable, it shifts toward the noble potential side. But additional alloy elements and cations de not affect the activating potential.
(3) Aluminium is affected after an induction period when it is held under prolonged potentiostatic electrolysis at the potential more basic than critical activating potential. The activating induction peroid depends on the potential and concentration of Cl−. The interval of the period is reduced with increasing potential and also with increasing concentration of Cl−.
(4) Aluminium is activated even at the potential lower than activating potential and pitting corrosion occurs proportionally with activating. Therefore, it is uncertain whether the critical activating potential of the anodic polarization curves is a pitting potential.View full abstractDownload PDF (1206K) -
Sho Teramae, Koji Yamada, Yasuhiko Miyoshi1967 Volume 31 Issue 9 Pages 1028-1033
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSamples of tinplate were cathodically treated in sodium bichromate solutions with pH values of 1∼8 for 1∼90 seconds. Surface films formed by these treatments were investigated by means of electron microscopy, using a replication and separation technique, to clarify their growth mechanism, and then examined by electron diffraction. Also, the reduction value of surface oxide, cathodic polarization, porosity and surface chromium content were measured as a function of treatment time to study the growth rate of the film.
The results are summarized as follows:
(1) The passivation film formed on the surface of tinplate by the cathodic treatment is not uniform in thickness, and its formation is affected by the pH of treatment solutions. That which is produced in an acid solution covers a larger area.
(2) The film grows rapidly to some extent in less than 1 sec, after which its growth is made slowly. The growth rate, though decreases with increasing treatment time, does not follow a simple functional time dependence.
(3) A compound with a tetragonal crystal structure is present in the film.View full abstractDownload PDF (1777K) -
Kiyoshi Azuma, Hideo Abe, Sakichi Goto, Kunio Ito, Y. C. Wu1967 Volume 31 Issue 9 Pages 1034-1036
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA new type of growth texture has been found in the columnar grain region of αFe-Zn alloy developed by diffusion of zinc into an electrolytic iron sheet. The longitudinal axes of the columnar grains were determined to be almost completely parallel to their [111] directions. Some possible mechanisms for the preferrential nucleation or growth of the [111]-oriented grains were discussed.View full abstractDownload PDF (655K) -
Goro Ito, Seiichi Ikeda1967 Volume 31 Issue 9 Pages 1036-1041
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe mechanical properties and oxidation resistance of Fe-Al-Cr alloys containing 8∼14% aluminium and 5% chromium in carbon dioxide gas at the temperatures of 600°∼900°C under a pressure of 10 kg/cm2 were studied. The results of experiments were summarized as follows:
(1) The oxidation of Fe-Al-Cr alloys at the temperatures tested decreased with increasing aluminium content. The oxidation rate of the alloys decreased with time and finally approaches a plateau after 300 hr.
(2) The oxidation resistance of Fe-Al alloys could be improved by the addition of more than 5% chromium provided that the content of aluminium is over 8%.
(3) The internal oxidation of aluminium observed in the Fe-Al alloys containing 8-10% aluminium was inhibited by the addition of chromium.
(4) The oxide formed at the temperature of 700°C was identified by an electron diffraction technique as a mixture of α- Fe2O3 and α-Al2O3, but the formation of α-Al2O3 was prodominant over 800°C.
(5) The tensile properties and hardness of Fe-Al alloys at the temperatures of up to 800°C were not affected by the addition of chromium.
(6) The ductility of Fe-Al(8%)-Cr(5%) alloy was makedly decreased by heating in carbon dioxide gas, and this phenomenon is attributed to the precipitation of chromium carbide at the grain boundary due to the carburization in high temperature gas.
(7) The decrease of creep resistance of Fe-Al alloys with increasing aluminium content could not be improved by the addition of chromium.View full abstractDownload PDF (1465K) -
Keisuke Matsuura, Takeshi Nishiyama, Shigeyasu Koda1967 Volume 31 Issue 9 Pages 1042-1048
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTensile testing of Al-5.6 wt%Mg and Al-8.6 wt%Mg alloys was carried out in the temperature range −194°C to 200°C to make clear the nature of the Portevin-Le Chatelier effect. The temperature dependence of repeated yielding in stress-strain curves, slip line appearence and dislocation distribution were investigated in the alloys.
The behaviour of repeated yielding at the temperatures below −40°C was well explained by Friedel’s relation based on Cottrell’s model. From the comparision of this relation with the present results, it was concluded that the activation energy of migration of vacancy was 0.27 eV in this phenomenon and the solute concentration reached about 40% in the dislocation core when the repeated yielding started.
However, Cottrell’s model was not valid for the repeated yielding at the temperatures above −20°C, because the behaviour of repeated yielding in this temperature range was quite different from Friedel’s relation. Here, the repeated yielding should be controlled by the release of dislocations from Cottrell’s locking, because the dislocations have been sufficiently locked by solute atoms in the early stage of deformation.
No changes in dislocation distribution and slip line appearance could be recognized by changing strain rate and deformation temperature, although they affected appreciably the appearance of repeated yielding.View full abstractDownload PDF (1640K) -
Takeo Oki, Jun Tanikawa1967 Volume 31 Issue 9 Pages 1048-1052
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSome experiments on the reduction of UO3 by calcium vapor and melting of the coarse (produced) uranium powder have been performed to determine the optimum condition for preparing a uranium metal powder with good fusibility and high purity. Further experiments for preparing a small uranium metal ingot from the produced uranium powder have been done. The results obtained are as follows:
1. Optimum condition for preparing coarse uranium powder is: reaction temperature, 1100°C; Ca/UO3 mol-ratio, 9; reaction time, 2∼3 hr (in case of this experimental scale); yield percentage of coarse uranium powder (gray-white) is more than 90%.
2. The coarse uranium powder (gray-white) has better fusibility than the fine one (black or brown-black).
3. Favourable conditions for making small uranium ingot are: temperature, >1200°C; atmosphere, argon gas (1 atm); metallic calcium is put outside of the crucible in the vessel.
4. Purity of small uranium ingot obtained is more than 99.9%. Contents of impurities (typical) are: Al, 3.2 ppm; Cd, 0.3 ppm; Co, 0.8 ppm; Cr, 7 ppm; Fe, 37 ppm; Mg, 14.5 ppm; Mn, 3.4 ppm; Ni, 54 ppm; Si, 43 ppm; Cu, 7 ppm; P, 44 ppm; Pb, 0.4 ppm.View full abstractDownload PDF (1349K) -
Yoshio Kamata, Takeshi Anbo1967 Volume 31 Issue 9 Pages 1053-1057
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSColumnarization of high-coercivity Alnico alloys, such as Alnico 7 or 8 has been carried out by the addition of a small amount of S or Se. However, in the case of alloys containing higher Ti than Alnico 8, it has been difficult to coarsen the grain and to form the columnar crystal sufficiently by S or Se addition. The present authors studied the effects of the duplex addition of S and C on the columnarization of Alnico-type alloys containing more than 5%Ti. Moreover, the effect of Ti on the magnetic properties of these high-Ti alloys with a columnar structure was examined.
Consequently, even in the case of alloys containing more than 9%Ti, a coarsend grain structure and a sufficiently developed columnar crystal were obtained. Columnar crystallization dependence between Al, Ti and S, C, as compared with that between Al, Ti and S in the case of the single addition of S was made clear. As the Ti content increases, the remanence Br and energy product (BH)max decrease slightly and the coercive force Hc increases gradually. Br of 9600 G, Hc of 1630 Oe and (BH)max of 8.3 MGOe were obtained at 5.7%Ti, and Br of 9200 G, Hc of 1760 Oe and (BH)max of 7.65 MGOe at 6.4%Ti.View full abstractDownload PDF (1309K) -
Takashi Yasunaka, Tôru Araki1967 Volume 31 Issue 9 Pages 1058-1063
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA study was made of the effect of ausforming and marforming by rolling on the aging behavior and mechanical properties of Fe-25Ni-2Ti, Fe-30Ni and Fe-30Ni-0.1C alloy.
Age hardening of Fe-25Ni-2Ti alloy was accelerated by ausforming, but was not affected by marforming.
The strength of 20% red. ausformed and aged Fe-25Ni-2Ti alloy was lower than that of conventional heat-treated alloy, but the strength was increased with the amount of reduction, when over 20% reduction. The increase in 0.2% yield strength of ausformed and aged martensite in the tested steel was proportional to the rolling true strain of austenite, and strongly depended on carbon content. The increase rate of yield strength of aged Fe-25Ni-2Ti alloy was 0.10 kg/mm2/% true strain, when over 0.22 true strain, and of the same order as that of Fe-30Ni alloy, and then a half of that of Fe-30Ni-0.1C alloy.
The strength of Fe-25Ni-2Ti alloy was affected by ausforming temperature, while the strength of Fe-30Ni, Fe-30Ni-0.1C alloy was little affected by ausforming temperature.
Although marforming was effective in increasing the strength, the toughness was inferior as compared with ausforming. One of the reasons of good toughness of ausformed alloy seemed to be ascribed to its inhomogeneity of microstructure.View full abstractDownload PDF (2202K) -
Hisasuke Takeuchi1967 Volume 31 Issue 9 Pages 1064-1070
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInfluence of Ni/Fe ratio on the ductility of W-Ni-Fe Heavy Metals was studied. Sintered 95% tungsten alloys were prepared, using coreduced fine powder, with the varying Ni/Fe ratios of 1/9, 3/7, 5/5, 7/3, 8/2 and 9/1. In the case of alloys made by liquid-phase sintering, the optimum strength and ductility, as well as the lowest micro-hardness in matrix, were obtained at the Ni/Fe ratios from 5/5 to 7/3. The alloys made by solid-phase sintering were comparatively hard and less ductile. In most of the W-Ni alloys and W-Ni-Fe alloys with the Ni/Fe ratios less than 3/7, two phases were observed in the bonding matrix. It is to be noted that these alloys were relatively less ductile. Electron probe microanalysis of 80%W-Ni-Fe alloys revealed that the tungsten content in the matrices changed with the Ni/Fe ratio, reaching the minimum at the Ni/Fe ratio of 7/3.
It was concluded that the high ductility of W-Ni-Fe alloys was obtained when there was little tungsten dissolved in the matrix and no brittle phase was contained in the system.View full abstractDownload PDF (1255K) -
Tasaburo Nishioka, Yukio Yasukuni, Takeshi Nishioka1967 Volume 31 Issue 9 Pages 1070-1075
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn dieser Abhandlung wurde Einfluss der Wärmebehandlung auf die Erscheinung der sternförmigen Bruchfläche beim Zugversuch von Stahldraht untersucht und die folgenden Ergebnisse wurden hervorgegangen:
(1) Unter verschiedenen wärmebehandelten und gezogenen Stahldrähten bildet der vergütete zähe Stahldraht die sternförmige Bruchfläche am leichtest und dann folgen die weichgeglühten, bleipatentierten und luftpatentierten Drähte nacheinander. Beim ausgeglühten spröden Draht erscheint es nicht.
(2) Der bei Anlasstemperatur von 600° bis 680°C vergütete Draht zeigt die sternförmige Bruchfläche auch in wärmebehandeltem Zustand.
(3) Der patentiert-gezogene und sodann geglühte Stahldraht bildet die deutliche sternförmige Bruchflache bei Glühtemperatur von 400° bis 650°C.
(4) Über das Gefüge des Stahldrahtes, beim Gefüge aus streifigem Zementit tritt die sternförmige Bruchfläche leichter als aus körnigem Zementit in Erscheinung. Diese Neigung wird grösser mit feiner und gleichmässiger werdendem Gefüge sowie mit zunehmender Streckung des Gefüges durch Ziehen und Einschnüren.View full abstractDownload PDF (711K) -
Minoru Tanaka, Tomoo Suzuki, Masayoshi Yodogawa1967 Volume 31 Issue 9 Pages 1075-1081
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe age-hardening response of martensitic structures of Fe-Ni-Mn ternary alloys was studied in relation to their dilatation, microstructures and the results of X-ray diffraction tests.
Age-hardening was observed at 450°∼500°C in the decomposition process of metastable, supersaturated Fe-Ni-Mn martensitic structures in the egg-shaped region around the composition of 12%Ni and 6%Mn. In this region, the increment of hardness was measured as 10∼12 in Rockwell-A scale, and the Ms points of alloys were observed at about 100°C.
It was concluded that the hardening occurred due to the internal strain caused by the compositional fluctuation in the matrix as in the case of Fe-Ni-Co alloy or by the precipitation of NiMn phase (bcc).View full abstractDownload PDF (617K) -
Tomoo Suzuki1967 Volume 31 Issue 9 Pages 1081-1088
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe agehardening response of martensitic structures of Fe-Mn-Co ternary alloys was studied in relation totheir dilatation, microstructures and the results of X-ray diffraction tests.
Age-hardening was observed at 500°∼550°C in the decomposition process of the Fe-Mn-Co martensitic structure in the comma-shaped region around the composition range of 15%Mn, 20∼50%Co to Mn 13% 50%Co. This hardening was a hardeness increment of 9∼10 in the Rockwell-A scale.
The Fe-Mn-Co alloys containing about 50%Co, however, showed an additional isothermal transformation of γ to α at a higher temperature than the athermal martensitic transformation point. In these alloys the weak hardening effect due to ordering was observed at low-temperature ageing, as is the case with Fe-Ni-Co alloys.
It was concluded that (1) hardening occurred due to the internal strain caused by the compositional fluctuation or/and the fine dispersion of austenite with highly concentrated solute atoms as in the cases of hardening in Fe-Ni-Co or Fe-Ni-Mn alloys already reported, and (2) the isothermal transformation of Fe-50%Co-Mn alloys was caused by the formation of ordered α phase from the γ phase.View full abstractDownload PDF (1730K) -
Asahi Kawashima, Michinori Takano, Saburo Shimodaira1967 Volume 31 Issue 9 Pages 1089-1095
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe propagation of stress-corrosion cracking in the brass-ammonia system was studied by means of an impedance bridge method.
The apparatus was designed to continuously measure impedance changes due solely to stress-corrosion cracking with an accuracy of 10−6 ohm, eliminating the effect of temperature change and general corrosion by the use of reference specimen.
Based on impedance-time curves obtained from stressed specimens in corrosives, the process of initiation and the growth of stress-corrosion cracking and the effects of the zinc content or the corrosive environment on stress-corrosion cracking susceptibility were discussed. The curves do not show any discontinuous crack propagation step as a brittle fracture. Under anodic polarization the crack propagation is accelerated with increasing current density, but at current densities larger than 0.5 mA/cm2, cracking hardly occurs. The crack propagation was stopped when polarized cathodically.View full abstractDownload PDF (2064K) -
Yûnoshin Imai, Tsuyoshi Masumoto, Masatoshi Sakamoto1967 Volume 31 Issue 9 Pages 1095-1100
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of nickel on the solubility of Fe4N and the diffusion of nitrogen in α-iron was examined by an internal friction technique. The used materials were pure iron and iron alloys containing 0.5, 1.0, 2.1 and 4.7 wt% nickel. The experimental results are as follows:
(1) During measuring the Snoek peak of internal friction, it is necessary to apply the magnetic field of more than about 80 Oe to the specimen in order to eliminate the magnetoelastic damping.
(2) The Snoek peak due to nitrogen in iron-nickel alloys takes place by the single relaxation mechanism.
(3) The diffusion of nitrogen in α solid solution of iron and iron-nickel alloys was examined in the frequency range from 0.5 to 2.0 cps. Consequently, the diffusion coefficent of nitrogen in these alloys is represented by D=2.2×10−3exp(−18000⁄RT) and the effect of nickel on diffusion is negligible.
(4) The solubility of Fe4N in α-iron is given by the equation log(N%)=−1230⁄T+0.36, and the heat of solution of Fe4N for α-iron is about 5600 cal/mol. The increase of nickel content dissolved in α solid solution has an effect of decreasing the solubility of Fe4N and has an effect of increasing the heat of solution of Fe4N.View full abstractDownload PDF (1186K) -
Hisashi Suzuki, Kozi Hayashi, Ichiro Kawakatsu1967 Volume 31 Issue 9 Pages 1100-1106
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInvestigations were made on fundamental properties of various WC-βt-10%Co alloys (βt=WC-TiC-TaC triple carbide phase having definite ratio of 70/30 in WC/TiC) affected by the carbon content, i.e., the binder phase composition. Specimens were vacuum-sintered at 1400°C for 1 hr.
Results obtained were as follows: (1) The amount of dissolved W in the γ-phase was considered to be the same as in WC-Co, WC-TaC-Co or WC-TiC-Co alloys; that is, it was in the range of 9∼10% in maximum and 1∼2% in minimum according to the carbon content. Ti and Ta hardly dissolved in the γ-phase. (2) The maximum carbon content in the βt-phase gradually approached the stoichiometric value with increasing tantalum carbide content, and the maximum carbon content reached the stoichio metric value at the content of more than 50∼60%TaC. (3) Hardness and strength of the alloys having the βt-phase with 50∼60%TaC were superior to those of the other alloys. (4) The range of the (WC+βt+γ) three-phase region and the mechanical properties of the alloys were mainly controlled by the titanium carbide content, but not by the tantalum carbide content in the alloys. (5) Magnetic saturation, specific gravity, hardness and lattice parameters of both γ and βt phases showed a change with the carbon content in the alloys.View full abstractDownload PDF (1746K) -
Takashi Sakaki1967 Volume 31 Issue 9 Pages 1106-1111
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn experiment was carried out to establish a simple and accurate method for the determination of microamounts of lead in high alloy steel.
The lead was separated as thionalide complex from the iron and other elements in an ammoniacal solution in which were masked those elements by use of ammonium tartrate, sodium cyanide and sodium sulfite. By means of this separation method with thionalide, the lead can be separated easily and accuratlly from large amounts of iron, manganese, nickel, chromium, molybdenum, copper, tungsten, vanadium, cobalt, titanium, aluminum, zirconium and others. Niobium and tantalum were separated beforhand as pentaoxides from other elements by the hydrolysis method with sodium sulfite and tannic acid.
The separated lead was determined by the spectrophotometric method with dithizone.
As a result of the experiment, the author succeeded in establishing a method in which less than 0.005% of lead in high alloy steel can precisely be measured without difficulty.
The lead contents in synthetic samples were measured by this method with satisfactory results.View full abstractDownload PDF (980K) -
Masao Ibaraki, Taira Okamoto, Katsuhiko Kishitake1967 Volume 31 Issue 9 Pages 1112-1116
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of growth conditions and alloy constituents on the breakdown of columnar growth has been investigated in the aluminum-coppe-silicon ternary system. The columnar-equiaxed transition in ternary alloy ingots is accounted for by the formation of equiaxed grains in the constitutionally supercooled region, as in binary alloys. However, it must be assumed that some form of interaction exists between the two solutes in the ternary system. With the interaction factor to be taken into consideration, an analysis of the experimental results indicates that the columnar to the equiaxed transition in the ternary Al-Cu-Si system may be expressed by the equation (G_L/R^1/2)_Al-Cu-Si=0.75C_Si-0.29C_Cu-0.084C_SiC_Cu, where GL is the temperature gradient in the liquid contacted with growing dendrite tips in °C/cm, R the freezing rate at the position of the transition in cm/sec, and CSi is the silicon content, and CCu the copper content in wt%.View full abstractDownload PDF (449K) -
Hakaru Masumoto, Takeo Kobayashi, Y\={u}etsu Murakami1967 Volume 31 Issue 9 Pages 1117-1121
Published: 1967
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFollowing the disovery of a new high magnetic permeability alloy “Nimalloy” in the system of nickel and manganese, the present authors made a study of the effect of additions of iron and vanadium on its magnetic properties. The highest value of initial and maximum permeabilities obtained were 39,200 and 213,000, respectively. The present investigation on the influence of the addition of silicon on magnetic properties of “Nimalloy” has revealed that the initial and maximum permeabilities of the alloy are increased generally by the addition of a small amount of silicon. Thus the alloy containing 8.77% manganese and 3.55% silicon shows the initial permeability of 22,500 when reheated at 400°C for 80 hr after cooling at a rate of 240°C/hr from 900°C, and the alloy containing 9.24% manganese and 3.57% silicon exhibits the maximum permeability of 140,000 when reheated at 380°C for 19 hr after cooling at a rate of 240°C/hr from 900°C. The alloy containing 8.28% manganese and 4.18% silicon shows the magnetic hysteresis loss of 3.67 erg/cm3/cycle and the coercive force of 0.0076 Oe for the maximum induction of 2,000 G when reheated at 400°C for 50 hr after cooling at a rate of 240°C/hr from 900°C, its specific electrical resistivity being 55.7 μΩ-cm at 20°C.View full abstractDownload PDF (323K)
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