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Volume 25, Issue 5
Displaying 1-16 of 16 articles from this issue
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Teishiro Oda, Tatsuo Murasaki, Katsuaki Uehara1961 Volume 25 Issue 5 Pages 301-305
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFeed heater tubes of aluminium brass used for high temperature and high pressure boilers are liable to intergranular corrosion in hot water or steam. On this problem of intergranular corrosion we have conducted fundamental researches with tubes used in the actual plant and with pieces heated in autoclaves, using an electron microscope and the electron or X-ray diffraction methods. The following conclusion has been reached. (1) The intergranular corrosion products detected by the electron diffraction method were ZnAl2O4, CuAl2O4, γ-Al2O3, ZnO, Cu2O, CuO, etc., and the larger part of these products were Zn or Al oxides. It was also found that the atom density of the alloying element in the vicinity of the grain boundary was reduced to a level closely approximating that of pure copper. (2) In the analyses of the metal phase of the oxidized region by the X-ray diffraction method, it was found that the lattice constant did not change, and decrease in the amount of Zn was noticed. (3) From the above results, it is inferred that the dissolved oxygen in hot water and steam penetrates into the inside of the metal through grain boundaries and combines with elements having large affinity to oxygen such as Zn or Al, that is, the intergranular corrosion of aluminium brass in hot water or steam arises from the grain boundary oxidation.View full abstractDownload PDF (1244K) -
Satoru Mito1961 Volume 25 Issue 5 Pages 305-309
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe brittleness accompanying the recrystallization in W filament was investigated by measuring several mechanical properties, electrical resistivity and microstructures. In the straight specimen the brittleness was detected clearly by the bending test, while in the coiled one the decrease of the plastic elongation of coil well corresponded with its recrystallization brittleness. From the observation on the relation between the ductility and the microstructure in coiled specimens, it was found that W filaments which showed long grain-boundary structure were not always brittle after recrystallization. Several considerations were given on the mechanism of the formation of a long grain-boundary structure and analogous experiments were tried on the grain-boundary control in Cu plate. And it was clarified that such long boundary-structure can be formed by adequate doping treatment in such a popular metal as Cu.View full abstractDownload PDF (1265K) -
Genjiro Mima, Shigenori Hori1961 Volume 25 Issue 5 Pages 309-313
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSLittle attention has been paid to the way in which the isothermal transformation characteristics of steel may vary with variations in austenitizing treatment. Therefore, we studied the influence of austenitizing degree on the mechanical properties after completion of isothermal transformation of 0.68% carbon steel by means of tension-and-bending test. The progressing degree of austenizing and the homogeneity of the austenite greatly affected the mechanichal properties, in particular the tensile strength and the area contraction, after isothermal transformation of these steels. Insufficient austenizing treatment of the specimens results in inferior tensile-and-the bending properties. In the specimens incompletely austenized, the lower bainite formation process in isothermal transformation of the specimens of spheroidized pearlites differs from that of the specimens with lamellar pearlitic structure.View full abstractDownload PDF (912K) -
Yasuo Sasaki1961 Volume 25 Issue 5 Pages 313-317
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe titanium carbide solid solution (δ-phase)in Ti-C-Co system was compared with the sintered alloy from the view-point of oxidation resistance. The δ-phase alloy containing about 14.5%C and 4%Co was prepared by arc-melting in argon atmosphere. The sintered alloy containing about 14.5%C and 14%Co was prepared in argon atmosphere at 1380°C. Oxidation tests were carried out in dry oxygen at 1 atm. pressure at 750°C and 900°C. The amount of oxidation was measured with a quarz spring balance and the weight change of absorbent of CO2 generated from the specimen during the oxidation. The oxides were examined by X-ray analysis and microscopic observation. Most of the specimens nearly follow the parabolic rate law in oxidation. There is no great difference in the weight gain during oxidation between δ-phase alloy and sintered alloy. Oxides formed in these conditions are mixtures of CoO and TiO2 (rutile). The preferred oxidation of the intergranular part in sintered alloy and of δ-phase boundary occurs at early stage of oxidation.View full abstractDownload PDF (486K) -
Kazuo Ota, Ryuzo Hori1961 Volume 25 Issue 5 Pages 317-320
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the fluoride separation of cerium, the use of thorium possessing similar ionic radius as coprecipitant in the presence of NH4+ was introduced to the analysis of cast iron. The fluoride precipitate by this method is crystalline, so easy to handle in centrifugal tube, and moreover readily soluble in H3BO3 and H2SO4 mixture. The requisite time is shortened by eliminating the ignition of fluoride precipitate and successive dissolution by white-fuming with H2SO4 or HClO4, and also the procedure is more simplified. The fundamental conditions of fluoride precipitation and photometric procedure are investigated. In the fluoride precipitation the optimum amounts of reagents are 15 mL of H2SO4(6 N), 10 mg of Th, 10 mL of HF, and 10 mL of NH4OH in 100 mL of total volume. The amounts of H3BO3 and H2SO4 in the dissolution of fluoride precipitate give considerable effects on the absorbancy, and their optimum amounts at the color development are respectively 0.5 g and 5 mL in 80 mL of total volume. In the ultimate photometric determination, the absorbancy, is successfully measured at 320 mμ, and correction due to small amounts of adsorbed Fe3+ etc. can be made by decolorizing the developed Ce4+ alone with H2O2. The proposed method is suitable for determining 0.002∼0.1% of cerium in cast iron within about 1 hour.View full abstractDownload PDF (1284K) -
M. Sugiyama, H. Suzuki1961 Volume 25 Issue 5 Pages 321-324
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of free carbon contents in TiC powders on some room-temperature properties of TiC-30 and -50%Ni cermet was studied. By adding sugar carbon to as-received TiC powder having a fixed carbon content of 19.60%, the free carbon content was varied from 0.03 to 1.30%. Various cermets were vacuum-sintered in temperature range of 1300° to 1400°C for 1 hr. The results obtained were as the following: (1) The density, the hardness and the strength of cermets were decreased with increase of the free carbon contents. (2) A dispersion of free carbon in cermets was microscopically observed when the TiC powder had more than about 0.5% of free carbon. (3) These results showed that the free carbon in TiC powder seemed to be inactive to possible reactions, that is, increase of the fixed carbon content of TiC or reduction of the oxidized powders under the sintering condition. (4) The free carbon content in TiC powder for cermet application was thought to be less than 0.1 to 0.2%.View full abstractDownload PDF (900K) -
Akira Murata, Shoso Dohi1961 Volume 25 Issue 5 Pages 324-328
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSUsing the strain-anneal method, many iron single crystals were produced from pure iron sheets rolled by various reduction, then their crystallographic orientations were determined. The results obtained are as follows:- The lengthwise direction of single crystals, produced from iron sheet of 77% cold-rolling reduction, 0.4 mm in thickness, is near [001] or in a middle part of the stereographic triangle, and their normal direction of the top surfaces is near [211] or [110]. The lengthwise direction of single crystals produced from iron sheet of 89% cold-rolling reduction, 0.2 mm in thickness, is near [011], and their normal direction of the top surfaces is near [110] or [211]. The lengthwise direction of single crystals produced from iron sheet of 94% cold-rolling reduction, 0.1 mm in thickness, is near [011], [\bar111] or in the middle part of that, and their normal direction of the top surfaces is near [110], or [211]. The preferred orientation of single crystal plates obtained from a iron sheet rolled by 75% to 0.1 mm in thickness after intermediate annealing at 900°C for 6 hours is similar to that of a plate obtained from iron sheet rolled by 77% to 0.4 mm in thickness. Moreover, the orientation of single crystals is changed by the direction of cutting off from the sheet. From these results, it is clear that the orientation of single crystal plates of iron are changed by the initial rolling reduction and the cutting direction for the same pre-annealing.View full abstractDownload PDF (343K) -
Hideo Kaneko, Taiji Nishizawa, Koreaki Tamaki1961 Volume 25 Issue 5 Pages 328-331
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt is the purpose of this paper to discuss the effect of alloying elements upon the composition, the crystal structure and the distribution of sulfides in steels. Examinations of these sulfides by electrolytic isolation, X-ray diffraction and chemical analysis, coupled with microscopic observations, led to the following conclusions: (1) Co, Ni, Mo, W and Si have little effect on sulfides in steels except that these elements slightly dissolve into FeS. These sulfides appear in continuous network at the grain boundaries of matrix. (2) Cr and V concentrate in great amount into FeS, replacing the iron atoms in FeS lattice to attain the composition CrS and VS. These sulfides form a broken network pattern. (3) Mn, Nb, Ti, Zr and Al concentrate into sulfide phase, forming MnS, NbS, TiS, ZrS and Al2S3, respectively. NbS, TiS and Al2S3 form a peculiar network pattern, while MnS and ZrS are grobular, and disperse in the matrix. (4) FeS, CrS, VS, NbS and TiS have a NiAs-type hexagonal structure,but MnS and ZrS have a NaCl-type cubic one.View full abstractDownload PDF (634K) -
Masao Kawabata, Kozoh Yokota, Yukishige Fukase, Shoichi Katoh1961 Volume 25 Issue 5 Pages 332-336
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFollowing the rapid development of many superior nickel and cobalt-base alloys strengthened by the presence of the dispersions of intermetallic compounds within matrix, iron-base alloys of such types., e.g., A-286 and W-545, have been developed recently. The purpose of this investigation is to contribute to the development of these iron-base alloys, by giving data on the hot-strength potentialities and the effects of melting processes on the high temperature properties of modified alloys containing a small amount of Mo, W, V, Cb, Ti, Al and B in iron-base Cr 16%, Ni 20∼25% and Co 0∼10% alloys. Both air- and vacuum-melted forged bars were used for solution annealing, age hardening, short-time tensile tests, high-temperature creep-rupture tests, electron-microscopic and X-ray examinations. Specimens containing Ti and Al have conspicuous age-hardenable characteristics. These specimens are much the same in solution-annealing and age-hardening characteristics and short-time tensile strength, but the ductility after tensile test in the vacuum-melted specimens is superior to that in the air-melted. The creep-rupture properties of vacuum-melted alloys investigated up to 732°C were better than those of commercial alloys such as A-286, LCN-155 or S-816 and were comparable to those of Nimonic 80 A. By the X-ray diffraction data on the electrolytic extracts from these specimens after creep-rupture tests, MC, M23C6, σ phase, Lave’s phase, γ′ phase, boride and η phase have been identified. It might be suggested that the remarkable age-hardening and the high-rupture strength properties of these alloys are principally caused by a precipitation of γ′ type Ni3(Al,Ti).View full abstractDownload PDF (505K) -
Shigetoshi Takayanagi1961 Volume 25 Issue 5 Pages 336-340
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe oxidation of tungsten in powder form is investigated at the temperature below 400°C and at the oxygen pressure ranging from 10 to 400 mmHg. It is found that the apparent oxidation rate increases with the increase of the oxygen pressure PO2. Applying the model of double oxide layers, as previously described, to the present experimental results, the following facts are observed: (1) For the growth of the thin barrier scale layer, the parabolic rate constant kp increases with PO2n and the activation energy is 29.4 kcal/mol; (2) for the formation of the outer porous layer from the barrier scale, the linear rate constant kl increases with logPO2 and the activation energy is 18.9 kcal/mol. The kinetics of the formation of these layers is discussed and the obtained results are found to be reasonable.View full abstractDownload PDF (429K) -
T. Fujiwara, T. Kato1961 Volume 25 Issue 5 Pages 340-344
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMagnetostriction in isotropic Alnico magnet was studied by the of strain-gauge method. The results obtained were as follows: An increase in Co generally causes an increase in magnetostriction, except in some cases of heat-treatment. In the measurement of magnetostriction dependent upon Ni content for a basic material, an unusual change which was not correspondent to the change of magnetic properties was detected. The change of magnetostriction due to aging-treatment is not simple. However it is supposed from these results that there is in all probability another mechanism which was comfirmed for anisotropic magnet, Alnico 5, by the authors in the precipitation in isotropic Alnico magnet, too.View full abstractDownload PDF (356K) -
Nakaaki Oda, Noboru Katayama, Kazue Endo1961 Volume 25 Issue 5 Pages 345-349
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the previous report, the authors reported mainly on the influences of some factors in analytical method on the precision and accuracy in determination of gas contents in titanium by vacuum fusion technique with tin bath. The distribution of the grain size of sponge titanium produced by Kroll process is spread over so wide a range that it is presumed that there are segregations of gas impurities, especially oxygen. Therefore, segregation should be averaged so as to obtain the representative contents in any sample preparation. Under such consideration, advantages and disadvantages between a few procedures of sample preparation were investigated on the basis of experimental designation. Consequently, it has been confirmed that Pench-dividing procedure is the more desirable one compared with any other method of sample preparation. This procedure obtained by improvement of the previous one (mentioned in the first report) made it possible not only to determine gas quantities in sponge titanium itself, but also to obtain high precision in the result.View full abstractDownload PDF (408K) -
Kingo Kiyonaga, Kunio Shitori1961 Volume 25 Issue 5 Pages 349-353
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe carburized case properties of some practical case hardening steels were studied under gas carburizing and direct quenching conditions. The results obtained are as follows: The case properties such as case hardness, micro structures, toughness and retained austenite contents could be improved by lowering carburizing temperature and controlling surface carbon content within nearly the eutectoid range. Although case hardenability varied over a wide range depending on the type of steel and carbon content, it rose to maximum at about 0.6% carbon in all alloy steels examined.View full abstractDownload PDF (350K) -
Hisashi Yamamoto1961 Volume 25 Issue 5 Pages 353-357
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSNitriding in ammonia gas was applied to W-Co layer (36 wt%W) electrodeposited on mild steel to increase its hardness at a temperature lower than the temperature of hardening by carburizing or heating in vacuum. Consequently, the value of 1200 Hv was obtained by nitriding at 700°C or 800°C for 30 minutes, but such high value of hardness could not be obtained at lower temperature. In the case of this hardening the precipitation of β W2N was found to take place in α Co. Next, fine cracks were formed in W-Co deposit on mild steel when it was heated above 400°C. In order to disclose the cause of this cracking the volume of gas released from the deposit by heating and the thermal expansion of the deposit were measured. An abnormal shrinking of the deposit was observed during the heating from 400°C to 690°C and it created cracks in the deposit. This shrink seemed to be produced by the ordering transformation of α Co→Co3W in deposit.View full abstractDownload PDF (903K) -
Ryôzô Isomura, Hatsukichi Satô1961 Volume 25 Issue 5 Pages 357-359
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSApplication of Sachs’ method to the measurement of residual stresses in hard cylinders is difficult. The authors succeeded in carrying out the measurement by using electric spark machining for boring and a resistance strain meter for strain measurement. In the present paper, they deal with the problems encountered in the practice of this method and with their solutions, bearing in mind the measurement of the residual stresses in water-quenched carbon tool steel cylinders; the results on these cylinders are illustrated.View full abstractDownload PDF (230K) -
Ryôzô Isomura, Hatsukichi Satô1961 Volume 25 Issue 5 Pages 360-364
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSBaseing themselves on the results of actual measurements of quenching stresses, the authors considered the quench-cracking phenomena in high carbon steel cylinders, and arrived at the following conclusions: (1) Quenching cracks due to water quenching frequently occur in the state of surface compression. They are caused by a tri-axial tension below the surface. (2) Great liability to quenching cracks at high quenching temperatures is attributed not to the quenching stresses but to the reduction of strength due to overheating. (3) Intensification of the effect of thermal contraction results in less liability to quenching cracks, while an increase in the effect of transformational expansion results in greater liability to them. (4) Tempering can considerably decrease the quenching stresses; so tempering immediately after quenching would be effective for prevention of quenching cracks (aging cracks).View full abstractDownload PDF (383K)
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