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Volume 30, Issue 8
Displaying 1-18 of 18 articles from this issue
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Kyuya Nagasaki, Mayumi Someno, Chou-Ming Chen, Hideo Hanazawa1966 Volume 30 Issue 8 Pages 709-713
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe Anodic behaviors of annealed iron-chromium (5∼30 wt%) and iron-nickel (10∼90 wt%) alloys were investigated in various concentrations of deaerated sulfuric acid solutions at 30°C by means of a potentiostat. The results may be summarized as follows:
(1) Fe-Cr (Cr<10%) and all Fe-Ni alloys have two passivities. The higher the concentration of the sulfuric acid solution, the more the first passivation potential moves to the base direction and the second passivation potential to the noble direction; the passivation current becomes smaller.
(2) Fe-Cr (Cr>16%) alloys have only one passivity. The higher the concentration of surfuric acid, the more the passivation potential moves to the noble direction; the passivation current becomes larger.
(3) The anodic behavior of Fe-Ni (<30%) is some what different that of Fe-Ni (>50%).View full abstractDownload PDF (1651K) -
Kyuya Nagasaki, Mayumi Someno, Chou-Ming Chen1966 Volume 30 Issue 8 Pages 714-718
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe first passivity film in the sulfuric acid and Fe2(SO4)3 solution was investigated by means of potentiostat, X-ray microanalysis, ion reaction, X-ray diffraction, etc., and the results are as follows:
(1) When the Fe2(SO4)3 concentration is above 5 N, a jump in corrosion potential of iron occurs and the formation of ferrous sulfate is observed.
(2) When H2SO4 concentration is high, Fe, Fe-Cr (Cr<10%), Fe-Ni (Ni<30%) have two passivities. The first passivity is considered due to the formation of ferrous sulfate.
(3) The formation of the second passivity film from the first is discussed as follows: 2FeSO4 ·mH2O → Fe2O3+6H++2SO4−−+(2m-3)H2O+2eView full abstractDownload PDF (1168K) -
Kenzaburô Kumada1966 Volume 30 Issue 8 Pages 719-724
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffects of nickel on the formation of the sigma phase in 25% chromium steels, containing 9 to 26% nickel, were studied by measurements of the magnetic and dilatometric properties, hardness and microscopic observations during annealing at 800°C up to 1000 hours after solution treatment at 1150°C for one hour after air cooling. It was shown that after 100 hours of annealing very fine particles of the sigma phase were formed at austenite grain boundaries in a specimen containing 26% nickel, and the sigma content became smaller with increasing nickel content and formed easily from the ferrite which coexisted with austenite.View full abstractDownload PDF (2506K) -
Kenzaburô Kumada1966 Volume 30 Issue 8 Pages 725-729
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSContractions by the sigma transformation of 44% chromium steel variously pre-heat treated in the temperature range from 650° to 800°C were measured with a dilatometer and thermal expansion coefficients of the sigma phase were calculated from the dilatometric curves. Expansion coefficients of the sigma phase varied by pre-heat treatments and their formation temperatures. Effects of molybdenum up to 2 wt% on contractions by the sigma transformation and on thermal expansion coefficients of the sigma phase were also studied. It was shown that the expansion coefficient increases with the molybdenum content.View full abstractDownload PDF (1578K) -
Hiroshi Kojima, Chyoji Miyakawa1966 Volume 30 Issue 8 Pages 729-733
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn examination was made on the accuracy of the quantitative analysis by an X -ray diffractometer for the binary system of known composition, the relation between diffracted intensity and concentration was determined. The results are summarized as follows:
(1) In the scope of present experiments, the maximum height of the diffracted line obtained by a slow scanning speed can be used for analysis with the same degree of accuracy as that of the integrated intensity.
(2) Using the intensity ratio of (104) in Fe2O3 and (107) in BaFe12O19, the maximum standard deviation of 0.37% can be expected for the analytical value in the range less than 10% Fe2O3 and 0.7% in the range of 60∼100% Fe2O3, respectively.
(3) To reduce the error due to the variation of the intensity ratio in the same component, two lines for each phase, i.e., (104), (110) in Fe2O3 and (107), (114) in BaFe12O19, are used for analysis. But it shows an accuracy similar to the results obtained in (2).
(4) The amount of Fe2O3 in various samples of BaFe12O19 prepared by the precipitation method is determined from the obtained calibration curve by means of X-ray diffraction. Compared with the changes in their magnetic properties, the results may be regarded as appropriate.View full abstractDownload PDF (1331K) -
Makoto Endoh, Jirou Namekata1966 Volume 30 Issue 8 Pages 734-739
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn investigation was made of the changes in hardness and microstructures of 17Mn-12Cr austenite steel containing up to 0∼2.7%V when aged or tempered after solution treatment. The result are as follows: (1) The hardening responses of Mn-Cr austenite steels containing vanadium (0∼2.7%) occur by aging or tempering after solution treatment, and the hardening increases with vanadium content. (2) The temper hardening of 17Mn-12Cr austenite steel containing no vanadium takes place from the tempering temperature of 800°C and the hardness peak is obtained at the tempering temperature of 1000°C. This hardening has some relation with the precipitation of the MC type carbides. (3) The temper hardening of 17Mn-12Cr austenite steels containing vanadium results in the hardness peak at the tempering temperature of 800°C, and is chiefly concerned with the precipitation of very fine VC carbides. (4) The temper hardening of the steel containing 0.6% vanadium takes place with two hardness peaks, i.e., the first peak at 800°C, and the second at 1000°C. The first peak takes part in the precipitation of VC carbides, and the second peak has relation with the precipitation of carbides of the MC type. (5) The tempering age hardening responses of 17Mn-12Cr austenitic steel containing 2.1% vanadium corresponds to the continuous transition of the precipitate from the intermediate phase coherent with the austenite matrix to the equilibrium phase of VC carbide. The precipitates can not be observed at the early stage of the hardening.
At the stage of the hardening peak, considerably fine particles of the precipitates are observed to be distributed uniformuly in the austenite grains.View full abstractDownload PDF (2638K) -
Yûnoshin Imai, Takeo Murata1966 Volume 30 Issue 8 Pages 740-744
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTensile creep tests have been carried out with ferritic iron-chromium alloys (15, 20 and 25 wt%Cr) at temperatures ranging from 600° to 800°C and stresses up to 5 kg/mm2. The temperature and stress dependences of the steady-state creep rate have been studied with special reference to the magnetic transformation. The results obtained are as follows: (1) The greatest activation energy for steady-state creep is obtained at the magnetic transformation temperature. The activation energy at the higher temperatures does not seem to depend on stress and is higher than the activation energy for self-diffusion. Besides, at the lower temperatures a gradual decrease is found as the stress increases. These values are comparatively higher than the activation energies obtained above the magnetic transformation temperatures. (2) The stress exponent does not seem to depend on the temperatures. Transitional decrease in the activation volume occurred with increasing stress and two activation volumes for steady-state creep are obtained at each testing temperature. Both values are much larger than the atomic volume and increase as the temperature rises. (3) The experimental evidence seems to be governed to some extent by the diffusion-controlled mechanisms, partly by the climbing of edge dislocations and partly by the non-conservative movement of jogged screw dislocations. The models based on the viscous motion of dislocations due to dragging of solute atmosphere and diffusional flow of vacancies without accompanying the motion of dislocations will not be operative.View full abstractDownload PDF (1491K) -
Keisuke Ikeda, Osamu Izumi, Eihachiro Tanaka1966 Volume 30 Issue 8 Pages 744-747
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAs to the effect of dispersed particles on the deformation texture, the structural analysis was carried out on the hot-extruded and cold-rolled specimens of S.A.P.-type alloy (Al-1.2∼12.7 wt%Al2O3). The extruded alloys tend to show a single ⟨111⟩ fibre texture, the degree of which decreases with an increase of the Al2O3 content. On the other hand, the rolling texture of low oxide content alloys is best described as {110}⟨447⟩, and the preferred orientation parallel to the rolling direction tends to change from ⟨112⟩ to ⟨111⟩ with increasing oxide content. These textures differ from those of pure aluminium, in which the hot-extrusion texture is ⟨111⟩+⟨100⟩ and the cold-rolling one is {110}⟨112⟩+{112}⟨111⟩. The difference was discussed in the light of the slip system and the crystal rotation.View full abstractDownload PDF (897K) -
Yûnoshin Imai, Tsuyoshi Masumoto, Masaaki Naka1966 Volume 30 Issue 8 Pages 747-754
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the present work, the isothermal structural diagrams of the 18%Cr-Fe-C-N system were examined at various temperatures between 1300°C and 700°C, in the range of compositions up to 0.5% carbon and nitrogen. In consideration of the phase relation, the structural diagrams were also obtained with various cross-sections of 0.1 and 0.2% nitrogen and 0.1, 0.2 and 0.3% carbon. The compound detected in the present work were the Cr23C6 type carbide and the Cr2N type nitride, the chemical formulas of which were expressed by (Fe7Cr16)C6 and (Cr1.95Fe0.05)C0.3N0.7, respectively.View full abstractDownload PDF (2177K) -
Ryoji Watanabe1966 Volume 30 Issue 8 Pages 754-759
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA high-purity copper-hafnium alloy system has been investigated. The hafnium content in the alloys varies from 0.08 to 1.73%. The solid solubility of hafnium in copper and some physical and mechanical properties of the alloys are determined. The maximum solid solubility of hafnium in copper is 0.96% at the eutectic temperature of 970°C. The alloys are age-hardenable and during aging the platelets of Cu7Hf2 precipitate on {111} habit planes of the matrix alloys. Tensile strengths of 44∼56 kg/mm2 and electrical conductivities of 68∼70% IACS are obtained for 0.43∼1.73% Cu-Hf alloys that have been solution heat treated, cold worked and aged at 450°C. It is known that copper-hafnium alloys are able to maintain the strength acquired by cold working at temperatures up to 450°∼500°C.View full abstractDownload PDF (1792K) -
Seiichi Nishikawa, Kazuo Nagata, Shigeyoshi Kobayashi1966 Volume 30 Issue 8 Pages 760-765
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCu-Cr alloys which were given various ageing and reversion treatments were investigated by electrical resistivity, hardness and transmission electron micrographs. Some results obtained are as follows: (1) The increment of electrical resistivity after the reversion at a constant temperature decreases as the ageing temperature rises, and disappears at about 400°C. (2) In a constant ageing condition, the increment of electrical resistivity after the reversion increases, and the time required for a max reversion becomes shorter as the reversion temperature rises. (3) The reversion phenomena can be repeated, but its amount decreases rapidly by repetition. (4) At first, the amount of reversion increases with ageing time and reaches its maximum, and then tends to decrease again. (5) Hardness changes by the reversion are very small, but the hardness tends to soften slightly. The precipitate responsible for the reversion phenomena seems to make little contribution to mechanical properties of the alloys. (6) Any changes in transmission electron micrographs by the reversion treatment cannot be detected. The above results may be reasonably explained by the reversion mechanism based on the critical size of the precipitate.View full abstractDownload PDF (1641K) -
Hideo Sugawara, Saburo Shimodaira1966 Volume 30 Issue 8 Pages 765-769
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe electrochemical behaviors of copper-zinc alloys in NaCl solutions were studied by means of a potentiodynamic method. The anodic polarization curves of α-brass in the 3% NaCl solution were similar to those of copper. The anodic current density observed in the active region before the first passivation of α+β brass was higher than α-brass but the other anodic behaviors were similar to those of α-brass. The anodic polarization of β-brass in the NaCl solution was smaller than α or α+β brass. The corrosion potential shifts to the less noble direction with increasing zinc contents in Cu-Zn alloys and the decrease of anodic polarization were observed. In the Cu-Zn coupling electrode, a great part of the anodic current were distributed over the zinc and the anodic current density on copper was low. The mixed potential change by dezincification layer formation during the corrosion of brass is deduced to explan the increase of corrosion velocity of brass. The cathodic polarization of brass increased with the zinc contents.View full abstractDownload PDF (1231K) -
Hideo Sugawara, Hideaki Ebiko, Saburo Shimodaira1966 Volume 30 Issue 8 Pages 770-775
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe observation with an optical microscope and an electron probe microanalyzer (EPMA) has been made on copper-zinc alloys electrochemically dezincified in a 3% NaCl aqueous solution and the Admiralty and Munty metal dezincified in practical use, respectively. In a groupe of α-brasses, the alloys of low zinc content are easily dezincified at the less noble potentials. In a two-phase brass, β-phase were dezincified more rapidly than α-brass, but the depth and morphology of the dezincified layer were independent of the potentiostatically applied potential. Measuring with EPMA, the Zn Kα radiation was not detected in the dezincified α-brass. On the other hand, in the two-phase brass the dezincified β phase grains emitted the Zn Kα radiation. The dezincification seems to start from the grain boundary and propagate into the inside of the grain. The Zn Kα radiation appears to be emitted from accumulated corrosion products of zinc near dissolution sites. Because of the presence of a surface films, the potential at the metal-solution interface may be less noble than the applied potential. At that potential, brass dissolve in the solution and the copper ions in the solution deposit on the brass surface.View full abstractDownload PDF (2382K) -
Hideo Sugawara, Saburo Shimodaira1966 Volume 30 Issue 8 Pages 775-779
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe electrochemical behaviors of brass containing 0.02∼0.20% arsenic in a 3%NaCl solution and of copper or copper-zinc alloys in 3%NaCl solutions containing 0.005∼0.5%NaAsO2 were studied by means of a potentiodynamic method. Anodic and cathodic polarization curves of Cu-30%Zn or Cu-40%Zn brass containing arsenic in the 3%NaCl solution are similar to those of arsenic free brass. The current density required for the first passivation in anodic region is higher in the orders of 0.056%As>0.013%As>0.186%As on Cu-30%Zn brass and 0.018%As>0.04%As>0.18%As on Cu-40%Zn brass. In the chloride solution containing 0.05∼0.5%NaAsO2, the increases in both anodic and cathodic polarizations on copper or copper-zinc alloys are larger than those in the NaAsO2-free solution. In the presence of 0.005%NaAsO2, the anodic and cathodic polarizations decrease on copper and increase on Cu-40%Zn alloy, but there is no effects on copper or Cu-30%Zn alloy. The corrosion inhibitive action appears to be due to the formation of arsenic or arsenious oxide film on copper-zinc alloys. Corrosion products of brass containing arsenic are complicated in structure. None of arsenic compounds listed A.S.T.M. card corresponds with electron diffraction rings of corrosion products.View full abstractDownload PDF (1347K) -
Tokuzou Tsujimoto, Masao Adachi1966 Volume 30 Issue 8 Pages 780-785
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe relations between hardness and tensile strength and between microstructures and tensile properties were studied on quenched Ti-2∼6%Al-2∼8%Co alloys. The features of tensile properties of various specimens were discussed from the rate of the strain hardening and microscopic observations. The tensile properties of the quenched-aged specimens were compared with those of the quenched specimens.
The results obtained for the quenched specimens are as follows: Hardness has a strong relationship with tensile strength, except for the specimens forming martensite from ratained β due to stress. The specimens forming martensite due to stress have the highest tensile strength and elongation, because they have a high rate of strain hardening. The rates of strain hardening for the specimens having the α+β structure with stable β and those for the specimens having the α+Ti2Co structure are nearly equal. In the specimens containing Ti2Co, the tensile strength and elongation are low. They cause the lowering of load at a lower uniform elongation than that expected from the rate of strain hardening. The lowering of load at a lower uniform elongation would be caused by the initiation of cracks at the part of aggregation of Ti2Co.
The specimens aged after quenching have high strength, but overaging to improve ductility lowers strength markedly.View full abstractDownload PDF (1399K) -
Teruo Ohashi, Zensaku Kozuka, Joichiro Moriyama1966 Volume 30 Issue 8 Pages 785-788
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe vapor pressure of selenium in Bi-Se alloys has been measured in the temperature range of 500°∼800°C by means of the “dew-point” method. Based on the these experimental results, P-T-x equilibrium relations of Bi-Se alloys were determined. The results obtained were as follows:
(1) The maximum melting point of Bi2Se3 and the monotectic temperature of this system were found to be 704° and 614°C, respectively. They were in good agreement with the previous reports. And also the vapor pressure of selenium at the composition corresponding to the maximum melting point was about 23 mmHg.
(2) It was found that there was a small solubility range of selenium in Bi2Se3, within which the vapor pressure of selenium remarkably changed with a slight change of the composition.View full abstractDownload PDF (915K) -
Shigeo Zaima, Kinichi Koyama, Mitsuhiro Muramoto1966 Volume 30 Issue 8 Pages 788-794
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe turning tests were carried out on aluminium cast alloys. The specimens were metal moulding rods of 80 mmφ×120 mm and were melted with different amounts of magnesium in the range of 0.5∼8.5%. The effects of magnesium additions on the machinability of aluminium alloys were examined mainly in the sight of the cutting resistance, cutting surface and growth of the built-up edge and chip treatment.
According to the results, the cutting resistance decreases gradually with the rise of the magnesium content and when the magnesium content is over 2.5%, the cutting resistance shows almost constant values with the cutting speed of 100∼600 m/min in this experiment. The cutting resistance of the G-2 tool shows a tendency similar to that of the SKH-4 tool, but the value of the former is about 40% higher than the latter. It seems that the cutting resistance of the alloy is not influenced by heat treatments such as quenching or tempering. However, it can be said that the hardness decreases and the cutting resistance increases slightly by quenching, and by tempring the cutting resistance decreases again slightly and is nearly equal to the as-cast cases. When the magnesium content is small, there is the formation of many built-up edges and continuous straight-type chips which poses a question of treatment. When the magnesium content is over 2.5% however, there is no such a problem. The surface roughness is comparatively good with more than 2.5% magnesium, and the surface of the as-cast alloy is inferior to the heat treated alloy. The machinability is improved by magnesium additions, but it seems that there is no great difference in the adding effect if the magnesium content is more than 2.5%.View full abstractDownload PDF (1912K) -
Masanobu Ohmori, Yoshitoyo Yoshinaga1966 Volume 30 Issue 8 Pages 794-800
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the present paper, the ductile-to-brittle transition behaviors in the standard Charpy V- and U-notched specimens of a killed carbon steel with 0.14%C were studied under the bending speeds of 0.05, 2.5, 33 and 5500 mm/sec. The results obtained are summarized as follows:
(1) The highest temperature at which the brittle crack appeared at the tip of the ductile tear was essentially constant, i.e., independent of the bending speed for the specimen with a given notch.
(2) The increase of the bending speed facilitated the propagation of the brittle crack, resulting in the increase of the slope of the transition curve. This phenomenon can be explained in terms of the strain rate effect.
(3) Estimated strain rate at the notch root was very high, which can be expressed reasonably by V/2ρ where V is the bending speed and ρ is the radius of the notch root.
(4) The brittle fracture stress below the notch was found to be about 105∼135 kg/mm2 for the V-notched specimen.View full abstractDownload PDF (2249K)
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