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Volume 22, Issue 2
Displaying 1-12 of 12 articles from this issue
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Sakae Takeuchi, Tsuneo Honma1958 Volume 22 Issue 2 Pages 55-59
Published: 1958
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFor investigating the effect of shot-peening on the fatigue in notched conditions, rotary bending fatigue tests were carried out on 1-R grooved and 90°-V notched specimens of Si-Mn spring steels, heat-treated to 140∼150 kg/mm2 in tensile strength. The results obtained were as follows: (1) The surface stressing by shot-peening was more effective on notched than on polished surfaces, and the fatigue limits were increased by 3.33 and 73% over that in the polished, in the 1-R grooved and the 90°-V notched specimens respectively, increasing in proportion to the notch factor (fatigue limit in polished specimen/fatigue limit in notched specimen. (2) The work was sufficiently effective even when the shot could not reach the root of notch. Accordingly, it is considered that shot-peening is always effective in preventing fatigue failure of structural materials under notched conditions in various types of stress concentration.View full abstractDownload PDF (753K) -
Sakae Takeuchi, Tsuneo Honma1958 Volume 22 Issue 2 Pages 59-63
Published: 1958
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt has been shown in our previous report that the surface stressing by shot-peening has a remarkable effect on the fatigue strength of steels and other metals having various types of surface weakness under non-corrosive atmosphere. In this paper, we examined the effect of shot-peening on the fatigue of Si-Mn steels under the corrosive atmosphere of distilled water and dilute H2SO4 solution. (1) The fatigue strength reduced under the atmosphere of distilled water was recovered considerably by shot-peening. For example,the fatigue limit at 107 cycles was increased from 36 kg/mm2 in the polished condition to 57 kg/mm2 in the shot-peened specimen,or about 58% in percentage. (2) In a dilute H2SO4 solution,the effect of shot-peening was reduced gradually in accordance with the increase of fatigue duration and of H2SO4 concentration,but it was still remarkable at short-time testing. (3) It was found from microscopic observation of the corrosion fatigued specimens that the propagation of fatigue cracks was prevented or delayed due to surface stressing, although the number of cracks in shot-peened specimens was much larger than in polished ones. Consequently, it is considered that the surface stressing by shot-peening is always effective in the view of prevention of fatigue failure under practical service condition which is usually accompanied by a somewhat corrosive atmosphere.View full abstractDownload PDF (950K) -
Tokushichi Mishima, Ryukiti R. Hasiguti, Yasuo Kimura1958 Volume 22 Issue 2 Pages 63-66
Published: 1958
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe coercive force of quench-hardened magnet steels has hitherto been explained by Becker’s internal stress theory. However, in the light of recent experience with iron and iron alloy, it is likely that stresses play rather a minor role. In this paper the magnetic properties, the Vickers hardness and the magnetic domain patterns of quench-hardened magnet steels (mainly MT magnet steel) were observed.As the results of measurements, it was found that the change of the coercive force is not proportional to that of the Vickers hardness, which is related to the internal stress, and that the coercive force is proportional to the square root of the volume, (1−v), of austenite. The best magnetic properties of quench-hardened magnet steels are obtained, when fine particles of martensite needles are distributed in the nonmagnetic retained austenite and the ratio of martensite to austenite is 2 to 1.View full abstractDownload PDF (747K) -
Masataka Sugiyama, Hisashi Suzuki1958 Volume 22 Issue 2 Pages 67-70
Published: 1958
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSExperiments on sintering 302 type stainless steel powder specimens prepared by intergranular corrosion and in addition,on those made by mechanical crashing were carried out.The density, the hardness, the tensile properties and the structures of compacts pressed at 30 to 60 tsi, sintered at 1100 to 1350° for 1 to 5 hrs and also resintered at 1200° for 1 hr after cold rolling of 10 to 40 per cent reduction in thickness were investigated.View full abstractDownload PDF (798K) -
Takuro Saga, Kinji Satô1958 Volume 22 Issue 2 Pages 70-73
Published: 1958
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe residual stress in aluminium-coated steel has been measured by using the equation described in our previous paper. The materials used were annealed mild steel sheets 0.2 mm thick. The successive uniform layers of material were removed chemically from the surface of a test specimen in order to introduce no further residual stress in the remaining material during removal. The following results were obtained. (1) Within the limit of our experiments, the effect of dipping temperature on the residual stress distribution is more perceptible than that of the dipping time. (2) The stress in the Al-layer derived from dipping process varies toward the compression side while its magnitude increases progressively with increasing dipping time and temperature. (3) The stress in the Fe-layer varies from the compression to the tension side with increasing dipping time and temperature. (4) At above 750° of the dipping temperature, the stress in Fe-layer and Al-layer showed tension and compression respectively.View full abstractDownload PDF (438K) -
Kunio Okabayashi1958 Volume 22 Issue 2 Pages 73-77
Published: 1958
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAs to the change in the characteristics of Mg-treated spheroidal graphite iron, the effects of remelting temperature and duration of molten state after remelting are reported in the present paper. Th results obtained are summarizede as follows. (1) The decrease of the residual Mg content due to remelting was faster at the earlier stage of remelting, but became gradually slower. (2) The initial spheroidal grpahite changed to nodular, and then, to irregular quasi-flaky graphite with the decrease of the residual Mg content in proportion to the duration after remelting. (3) At this stage a ledeburite structure appeared in the matrix and then its amount increased.It was an interesting phenomena that this chilled effect appeared with the decrease of the residual Mg content. (4) However, when the initial spheroidal graphite was remelted perfectly into molten iron, the chilled effect disappeared and suddenly changed to the D-type undercooled graphite structure, and then, gradually to the normal flaky graphite structure, (5) The structural change above mentioned became faster with higher remelting temperature. (6) Reappearance of spheroidal graphite iron due to remelting in the air can hardly be expected.View full abstractDownload PDF (1171K) -
Kunio Okabayashi1958 Volume 22 Issue 2 Pages 77-80
Published: 1958
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the previous paper, the change in the characteristics of Mg-treated spheroidal graphite iron caused by remelting was described in details. It was ascertained that the change occurred, keeping some relationship with the decrease in residual Mg content. Hence the change due to remelting should be deemed to originate in the behavior of residual Mg in molten iron remelted. In the present paper, some considerations were given to the relationship between the change in the characteristics caused by remelting and the behavior of residual Mg from the standpoint of the mechanism of spheroidal graphite formation due to Mg treatment. The results seemed to suggest that the effective state of residual Mg in spheroidal graphite iron may be found as an active state in the spheroidal graphite domain.View full abstractDownload PDF (793K) -
Akira Takaoki1958 Volume 22 Issue 2 Pages 81-84
Published: 1958
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe change of the attenuation of ultrasonic waves in steels due to compressive and bending stresses within the elastic limit were studied using a pulsed reflection method (3 mega cycles). The results obtained were as follows: (1) By the compressive stress in feeric steel, a small decrease of attenuation appeared in the direction of 0, 45 and 90 degrees to that of the principal stress. (2) In the case of austenitic steel no change of attenuation was brought from the action of compressive stress as well as tensile stress. (3) In ferritic steel, a little decrease of attenuation appeared by the bending stress although a little increase appeared by tensile and compressive stresses. (4) It may be considered that the change in attenuation by bending stress is due to the deformation of wave front caused by the inclination of the stress destribution or the stress field under the tensile and compressive stresses.View full abstractDownload PDF (589K) -
Akira Takaoki1958 Volume 22 Issue 2 Pages 84-87
Published: 1958
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe influences of thermal stress on the ultrasonic attenuation in large specimens of ferritic steel (150 mmDia.×450 mm) and of austenitic steel (70 mmDia.×210 mm etc.) have been studied using the same method as in the first report. The results obtained were as follows: (1) The same type of attenuation change by thermal stress was found in large specimens as well as in 70 mmDia. steel bar. (2) A thermal stress heavily influences the attenuation in austenitic steel although the tensile and compressive stresses have no influence. (3) It may be considered that the mechanism of attenuation by thermal stress is not the same as that by the simple tensile or compressive stress.View full abstractDownload PDF (591K) -
Hideo Nishimura, Tsuyoshi Hiramatsu1958 Volume 22 Issue 2 Pages 88-91
Published: 1958
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe equilibrium diagram of the titanium-palladium system has been investigated in the whole range of its composition by metallographic examination, X-ray analysis, and the measurements of melting points. The diagram obtained from the experimental results is shown in Fig. 5. Only an intermediate compound (TiPd3) was found to exist. The crystal structure of TiPd3 is of hexagonal DO24 type, and a=5.489 A, c=8.964 A and c⁄a=1.635. An eutectic reaction L\ ightleftarrowsβ+TiPd3 occurs at 47% palladium and 1080°, a peritectic reaction L+TiPd3\ ightleftarrowsγ (Pd) at 89% palladium, and an eutectoid reaction β\ ightleftarrowsα+TiPd3 at approximately 25% palladium and 735°. The solubility of palladium in beta-titanium is approximately 45% at the eutectic temperature and the solubility of palladium in alpha titanium is 5% at the eutectoid temperature. Also the solubility of titanium in gamma palladium is 11% at 1000°.View full abstractDownload PDF (1529K) -
Genjiro Mima, Yoshio Kuranuki1958 Volume 22 Issue 2 Pages 92-95
Published: 1958
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to study the interface tension between molten metals and fluxes or slags, which is a very interesting problem from both the theoretical and the practical view points, the authors set up an apparatus utilizing the drop weight method which automatically calculates the accurate drop number of molten metals by using a photoelectric tube, and measured the surface tension of Sn-Pb alloys and the interface tension in the ZnCl2:NH4Cl (7:1) flux. The results were as follows: (1) The surface tension of Sn-Pb alloys was expressed as a linear function of temperature. (2) The surface tension and its temperature coefficient of Sn were larger than those of Pb. On the Sn side, the surface tension of the alloys became lower corresponding to the change of activity while on the Pb side, it decreased abruptly. (3) The interface tension of Sn-Pb alloys was considerably lower than the surface tension.View full abstractDownload PDF (581K) -
Genjiro Mima, Yoshio Kuranuki1958 Volume 22 Issue 2 Pages 95-99
Published: 1958
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe surface tension of fluxes and the interface tension between molten Sn and fluxes were measured by the maximum bubble method and the drop weight method, respectively, in the temperature range of 300∼500°. The fluxes used were ZnCl2, SnCl2 and mixtures of ZnCl2 and NH4Cl NaCl, KCl or SnCl2. The results obtained are summarized as follows: (1) The surface tension of SnCl decreased while the surface tension of ZnCl2 increased with rising temperature. (2) The surface tension of mixed fluxes increased as the quantity of the 2nd or the 3rd element added to ZnCl2 increased. (3) The interface tension between Sn and ZnCl2 is expressed by the following equation: σ=730.4−0.564θ; where σ: interface tension, dynes/cm, θ: temperature, °C; (4) In the case of Sn and 2 component fluxes, it may be said that the addition of NH4Cl to ZnCl2 results in a larger decrease of the interface tension than the addition of NaCl, but the addition of SnCl2 shows no effect and the addition of KCl shows a small increase of the interface tension. (5) In the case of Sn and 3 component fluxes, by the addition of the 3rd elements (NaCl, SnCl2) to ZnCl2-NH4Cl, the decreasing effect of the interface tension by the 2nd element (NH4Cl) was lost.View full abstractDownload PDF (571K)
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