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Volume 36, Issue 8
Displaying 1-18 of 18 articles from this issue
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Toshio Shimoo, Hiroshi Kimura, Masao Kawai1972 Volume 36 Issue 8 Pages 723-727
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSContents of cyanide and carbide in molten CaO-Al2O3 and CaO-SiO2-Al2O3 were determined, and nitrogen dissolved in molten slag was discussed. It is clear that nitrogen dissolved in melt exists as both CN− and N3−, although the existence of CN22− was not confirmed. The content of CN− increases with increasing lime content, and decreases remarkably with increasing silica content. Furthermore, the content of CN− in melt is dependent on temperature and gas composition.View full abstractDownload PDF (1660K) -
Toshio Shimoo, Toshiharu Iida, Hiroshi Kimura, Masao Kawai1972 Volume 36 Issue 8 Pages 728-733
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe rate of absorption of nitrogen in molten CaO-Al2O3 and CaO-SiO2-Al2O3 slags were measured to discuss the rate-determining process. The results obtained are as follows:
(1) The rate of absorption of nitrogen can be expressed by the following equation:
(This article is not displayable. Please see full text pdf.)
(2) The apparent activation energies are 49 kcal/mol for 50CaO-50Al2O3 slag and 45 kcal/mol for 40CaO-40SiO2-20Al2O3 slag. In the CaO-SiO2-Al2O3 melt, the behavior of absorption of nitrogen is complicated as the result of reduction of silica by graphite.
(3) The apparent rate constant K′ increases with increasing lime content, and decreases with increasing silica content.
(4) K′ increases with increasing slag-graphite interfacial area.
(5) K′ is independent of the forced-stirring in melt.
(6) The rate-determining process is supposed to be the following anodic reaction:
(This article is not displayable. Please see full text pdf.)View full abstractDownload PDF (1874K) -
Yasuhiko Miyoshi, Satoshi Kado, Tadao Azami1972 Volume 36 Issue 8 Pages 734-738
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe oxidation behaviours of carbon steels containing 0.01∼0.5%Sn, Sb, As and Te at 700°C in air were studied by using a thermo-balance, EPMA, X-ray diffraction and optical microscope. The results obtained are summarized as follows:
(1) Small additions of Sn, Sb, As and Te considerably improve the oxidation resistance of carbon steel, their effects remaining unaltered with higher concentrations of the additives than a certain level. This is not due to the formation of a protective oxide film containing much of these elements.
(2) These elements are enriched in the metal phase near the metal-oxide interface, as can be expected from the free energies of formation of their oxides.
(3) The oxide scales formed consisted of layers of hematite, magnetite, wustite and wustite+fayalite, as is also found in the oxidation of a pure Fe-Si alloy. Sn, Sb, As and Te additions were found to change the nature of the innermost oxide layer, i.e. wustite+fayalite. Since the diffusion of the reacting atoms through this layer determines the overall oxidation rate, the protective effect of these elements can be explained to be brought about by the change of the nature of this layer.View full abstractDownload PDF (1968K) -
Atsumi Ohno, Tetsuichi Motegi1972 Volume 36 Issue 8 Pages 739-744
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTo know the origin of equiaxed crystals in unidirectionally cooled ingots, pure Sn, Sn-Pb, Sn-Zn and Sn-Sb alloys were melted in cylindrical graphite crucibles. Five thermocouples were placed in each of the crucibles to measure the temperature in the liquids. They were spaced at equal intervals from the bottom to the top with the fifth thermocouple just below the molten surface. The molten metals were cooled unidirectionally from the bottom and the top, and finally from the bottom and the top.
The results showed that there was no relationship between the place of columnar-equiaxed transition and the supercooling at the place where the transition was located after solidification.
It was proved that the equiaxed crystals were carried from the outer surface, i.e. the mold wall and cooled molten surface, where the crystals first nucleated and then separated.View full abstractDownload PDF (1996K) -
Kozo Osamura, Kazuo Nakajima, Yotaro Murakami1972 Volume 36 Issue 8 Pages 744-750
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSQuasi-binary phase diagrams between III-V compounds are calculated on the basis of a regular solution treatment. The interatction parameters are determined by fitting the calculated curves to the experimental data. Nine phase diagrams are analyzed in the present work.
The interaction parameter in the quasi-binary solid solution is found to be mainly determined by the energy produced by the elastic strain based upon the theoretical estimation.View full abstractDownload PDF (2069K) -
Tuguyasu Yoshii, Yoshihiro Hisamatsu1972 Volume 36 Issue 8 Pages 750-759
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSOn specimens of type-304 stainless steel, having passive films formed by treating at 0.30 V (SCE) for 1 hr in 1N-H2SO4, single pits were developed by the use of a chemical pitting solution, 1N-H2SO4+0.5N-FeCl3+0.001N-FeSO4, at 25°C. Initiation of a single pit was noticed by a sharp potential drop. The passivated surface of 1 cm2 was found not enough for a pit to continue growing. The rate of potential descent is so high thal the chemical pit becomes repassivated.
On the specimen that was connected with an auxiliary platinum micro-electrode, a single pit could continue to develope. The rate of potential descent was, in the early stages, 0.0088 V/min. After partial repassivation inside the pit, the potential reached about 0 V. At this external potential the electrode potential at the bottom of the pit was −0.15 V. The latter potential value means that the active-state dissolution does occur in the concentrated chloride solution at the growing front of the chemical pit. This situation of growth in the later stages is similar to that of the single galvanostatic pit reported in the preceding paper.
To compare the growth behavior of chemical pits with that of potentiostatic pits, the potential of the specimens having single pits grown potentiostatically to a predetermined size was lowered with constant sweep rates in 1N-H2SO4 containing 0.5N-NaCl at 25°C. The protection potential value of the pits depends upon the degree of growth and the sweep rate. When the sweep rate is high enough, the protection potential can coincide with the stationary pitting potential. Contrary to the behavior of chemical pits, the potentiostatic pits could be repassivated at 0.25 V at the constant rate of 0.0083 V/min.
The growth of deeply growing galvanostatic pits was ceased at −0.10 V where the steel is passive in the bulk solution.View full abstractDownload PDF (4046K) -
Ichiro Shiota, Osamu Watanabe1972 Volume 36 Issue 8 Pages 760-765
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCarbon fiber-Ni composites were prepared by means of Ni electro-deposition on carbon fiber sheets and hot press.
Composites with 85∼90% density of the theoretical values were obtained by hot press. No reaction was recognized at the interface between carbon fiber and nickle.
High temperature characters, especially thermal expansion coefficient \barα, were measured.
Theoretical analysis of \barα in the composites was carried out in consideration of compression and shear deformation.
The obtained datas agreed well with the calculated values.View full abstractDownload PDF (1407K) -
Mitsunori Sato, Masayuki Hijikata, Ichiro Morimoto1972 Volume 36 Issue 8 Pages 765-770
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSilver base alloys containing magnesium-, manganese- and lanthanum-oxide were prepared by the internal oxidation in air at 650°C. The characteristics of erosion resistance, welding resistance and contact resistance of these contacts have been measured under the conditions of an applied voltage of 100 volts and circuit currents from 10 to 50 amperes in alternating current.
The addition of lanthanum oxide is very effective to improve these characteristics. The contacts containing lanthanum oxide (0.5 at%La) have higher welding resistance and lower contact resistance than the silver-12 wt% cadmium oxide contact which is used very frequently, both contacts are comparable in erosion resistance. On the other hand, although the additions of magnesium and manganese oxides are not so good as that of lanthanum oxide, the erosion resistance of magnesium oxide (1.0 at%Mg) and manganese oxide (3.2 at%Mn) contacts are comparable with that of 12 wt% cadmium oxide contact in the high current region over 30 amperes. Furthermore, the change of the amount of erosion with current becames small for magnesium oxide and manganese oxide contacts.View full abstractDownload PDF (1882K) -
Mitsunori Sato, Masayuki Hijikata, Ichiro Morimoto1972 Volume 36 Issue 8 Pages 770-774
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFour silver base alloys containing two kinds of oxides, viz. manganese and zirconium oxides, magnesium and zirconium oxides, magnesium and lanthanum oxides and lanthanum and zirconium oxides, were prepared by the internal oxidation in the air at 650°C. For these contacts the characteristics of erosion resistance, welding resistance and contacts resistance were measured under the conditions of an applied voltage of 100 volts and circuit currents from 10 to 50 amperes in alternating current.
The coexistence of zirconium oxide with others is very effective to improve the welding resistance. As compared with the characteristics of silver-12 wt% cadmium oxide contacts which are used very frequently, the contacts containing lanthanum and zirconium oxides (0.40 at%La and 0.49 at%Zr) have higher welding resistance, but their erosion resistance is a little lower. It is also shown that magnesium and zirconium oxide contacts (0.49 at%Mg and 0.50 at%Zr) have almost the same erosion resistance and welding resistance. Furthermore, both contacts are comparable in contact resistance. On the other hand, the erosion resitance of manganese and zirconium oxides (2.0 at%Mn and 0.96%Zr), magnesium and zirconium oxides (0.49 at%Mg and 0.50 at%Zr) and magnesium and lanthanum oxides (0.49 at%Mg and 0.36 at%La) is improved in the high current region, because the circuit current dependency of the amount of erosion is less than that of other contacts.View full abstractDownload PDF (1569K) -
Shinji Koyama, Teruo Ishii, Kiichi Narita1972 Volume 36 Issue 8 Pages 775-778
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe solubilities of niobium carbide and nitride in iron austenite containing about 3%Ni and 1.5%Cr or 3%Ni, 1.5%Cr, 1%Mn and 0.4%Si have been measured by the method of equilibration with methane-hydrogen mixture gas or nitrogen.
The measured values of the solubility products of niobium carbide and nitride in the low-alloyed iron austenite agree approximately well with the calculated values obtained by adding arithmetically the part dependent on the content of alloying element in the logarithms of the solubility products of them in iron austenite containing each one of the elements. The results support the thermodynamic consideration on the solubility products of compounds in the multi-component solution.View full abstractDownload PDF (1533K) -
Hajime Suto, Norimasa Uchida1972 Volume 36 Issue 8 Pages 779-786
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStability of reverse austenites in three kinds of high nickel steels has been investigated. The 32%Ni-and 28%Ni-0.2%C-steels which athermally transform to martensite were chosen to investigate the effect of carbon content on the stability of reverse austenite, and the 24%Ni-3%Mn-steel used is well known to form isothermal martensite. The results obtained are as follows: (1) The major factor affecting the stability of reverse austenite in 34%Ni-steel is the dislocation density, and the contribution of re-distribution of nickel between α′ and γ seems to be relatively small. (2) The controlling mechanisums of stabilization of reverse austenite in 28%Ni-0.2%C-steel are considered to be the hardening by dislocations introduced during transformation, the lowering Ms point by resolution of carbide and the disparsion strengthening by undissolved carbide particles. (3) Transformation from martensite to austenite and that reverse transformation are retarded by cyclic transformation, and reach a saturate value after several cycles. (4) The reverse austenite in 24%Ni-3%Mn-steel hardly transforms to martensite isothermally at −78°C.View full abstractDownload PDF (3164K) -
Akinori Matsuda1972 Volume 36 Issue 8 Pages 787-790
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSLine broadening analyses of the retained austenite and martensite in quenched steel during the process of the low temperature tempering were investigated, and the results obtained are summarized as follows;
(1) The integral breadth of the retained austenite increased with decreasing of its volume fraction.
(2) For the retained austenite phase, the effective strain increased and the effective particle size decreased with the ageing process, and vice versa for the martensite phase.
(3) The dislocation density for martensite was estimated to be 4.7×1012/cm2 after tempering at 180°C for 30 min and it decreased with the ageing process, while that of the retained austenite, which is 5.1×1011/cm2, increased. The stabilization of retained austenite was discussed from these results.View full abstractDownload PDF (825K) -
Hiroshi Saito, Mayumi Someno1972 Volume 36 Issue 8 Pages 791-796
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe solubility of hydrogen in beta titanium and beta solid solution of its binary alloys with vanadium, chromium, manganese, iron, cobalt, nickel, copper, zirconium, niobium, molybdenum and tantalum has been measured by Sieverts’ method.
The measurements were made as a function of temperature in the range from 750 to 900°C and of hydrogen pressure from 0.5 to 25 mmHg. Solubility of hydrogen in all alloys investigated obeyed Sieverts’ law up to 5 atomic per cent.
All the alloying elements except zirconium, niobium and tantalum decrease the hydrogen solubility of titanium. The effect of each alloying element was described in terms of interaction parameter. Each alloying element has only a small effect on the heat of solution of hydrogen in beta titanium. Niobium was the only element that increased the heat of solution.View full abstractDownload PDF (1585K) -
Toshiyuki Suzuki, Katashi Masumoto1972 Volume 36 Issue 8 Pages 796-802
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to make the cause of quench-hardening in Ni-rich NiTi clear, the relation between composition and electrical resistivity and the change in the resistivity at constant rate of heating for NiTi have been measured.
On the Ni-rich side of the stoichiometry, the resistivity increases with increasing nickel content for water-quenched specimens and the resistivity remains constant at non-stoichiometric composition for slowly cooled specimens. The measurement on electrical resistivity at a constant rate of heating for water-quenched Ni-rich NiTi shows a significant decrease in resistivity around 300°C and 700°C. Above 700°C the resistivity changes in the same manner as slowly cooled specimens. Activation energies were 1.1 eV for low temperature reaction and 3.7 eV for high temperature reaction. Electrical resistivity for the specimens having stoichiometric composition and 55 at%Ni after being ordered just below critical temperature increases with increasing temperature. No significant change in the resistivity due to order-disorder transformation or eutectoid reaction was observed.
The analysis of the results on the electrical resistivity measurements indicates that the existence of order-disorder transformation and eutectoid reaction is improbable, and also the precipitation of Ni3Ti at water-quenched state is unlikely.View full abstractDownload PDF (2759K) -
Masanobu Ohmori, Shigeyuki Okimoto, Yoshitoyo Yoshinaga1972 Volume 36 Issue 8 Pages 803-808
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn a temperature range from −196 to 400°C, a commercially pure polycrystalline aluminium, 2S-Al, was tested in tension to study its ductility as a function of strain rate over a range from about 10−3 to 102/sec. Findings in the present study are given as follows:
(1) The total elongation measured in tension at a high strain rate, i.e., an impact tension, became larger than that measured in a quasi-static tension over the temperature range from −78 to 300°C, especially at room temperature to 200°C. This remarkable increase in elongation at a high strain rate may be attributed not to variations in grain boundary behaviours but to changes in behaviours of the matrix itself. The larger total elongation in the impact tension was brought, at least at room temperature, by the increase in both uniform and local elongations.
The reduction in area increased gradually with temperature and no dip was observed on the reduction-temperature curves in all cases, though a deep dip around about 100°C was found on the total elongation-temperature curves obtained in tension at lower strain rates.
(2) At room temperature, when the specimen was stretched incrementally to fracture, the total elongation was larger than that measured in a continuous tension, i.e., in a tension without unloading. The increase in total elongation due to an incremental deformation became larger in the impact tension and in tensions with larger repeated numbers of incremental deformation and with larger duration of unloading.
(3) The total elongation at −196°C decreased abruptly beyond the strain rate of 1/sec. This decrease was due mainly to the decrease of local elongation. Since at −196°C the aluminium specimen has a small value of specific heat and its strength decreases rapidly with increasing temperature, a necked portion of the specimen subjected to a rapid tension at −196°C becomes remakably weakened under the effect of an adiabatic temperature rise, as compared with other portions which are not necked. The necking generated in rapid tension at −196°C is, therefore, restricted within a shorter length of the specimen, showing a local elongation smaller than that observed in a quasistatic tension at the same temperature.View full abstractDownload PDF (2439K) -
Masahisa Otsuka, Ryo Horiuchi1972 Volume 36 Issue 8 Pages 809-817
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTo clarify the mechanism of high temperature deformation of Al-Mg alloy single crystals, the lattice rotation behavior was investigated experimentally and was compared with that of pure aluminum single crystals. The results are summarized as follows:
(1) While distinct asterism was observed in the back-reflection Laue photographs taken on crept aluminum crystals, it was hardly observed in high temperature deformation of Al-Mg alloys up to the extension of about 30%. This result shows that subgrains are not likely to be formed, and the direction of tension axis rotation was largely deviated from that predicted on the assumption of simple glide.
(2) Transmission electronmicroscopy showed that not only the primary dislocations but also the secondary ones contribute to the high temperature deformation of Al-Mg alloys and also that the dislocations mainly with an edge character are uniformly distributed in the crystals without forming subboundaries.
(3) The direction of tension axis rotation which is estimated on the assumption of doubl glide on the primary and the most probable secondary slip planes and the atmosphere dragging of dislocations as a rate controlling process, is in good agreement with the measured direction.
(4) It is concluded that high temperature deformation of Al-Mg alloy single crystals is controlled by the atmosphere dragging of dislocations and that in addition to the primary slip system some latent slip systems are activated probably due to the high dragging stress in comparison with the stress required for the forest cutting. These conclusions are consistent with those obtained in our previous work on high temperature creep of polycrystalline Al-Mg alloys.View full abstractDownload PDF (3413K) -
Kazumi Shimotori, Kagetaka Amano, Yoshiharu Fukasawa1972 Volume 36 Issue 8 Pages 818-825
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFrom the view point of the excellent resistance to hot corrosion, high Cr, Ni-base alloys seem highly potential, but their strengths are not sufficient. In this experiment, 15 heats of systematically varied compositions were prepared from the base alloy (36.4Cr, 1Al, 1Ti, 4Mo, 5Ta and balanceed with Ni). Tensile and stress rupture tests were carried out at 800°C. Metallographic examinations of the ruptured specimens and hardness measurements were also made. From these data, effects of Al, B, C, Co, Cr, Mo, Ta and Ti on the properties of the high Cr, Ni-base alloy were evaluated.
Additions of 1%Al and 1%Ti increased greatly the age hardenability and tensile strength, as in the case of Ni base superalloy. But the hardenability of this alloy was found to be due to the duplex precipitations of bcc α phase and ordered fcc γ′ phase. Almost no improvement in stress rupture strength was made by alloying with Al and Ti, but the strength of the alloy was improved when alloying was made in combination with Ta and/or Mo. Fractographic examinations revealed that there were predominant grain boundary cracks in the weaker specimens.View full abstractDownload PDF (2663K) -
1972 Volume 36 Issue 8 Pages 825
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPlease see pdf. Wrong:[Please see pdf] Right:[Please see pdf]View full abstractDownload PDF (24K)
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