JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 50 , Issue 11
Showing 1-18 articles out of 18 articles from the selected issue
  • Nobuya Iwamoto
    1981 Volume 50 Issue 11 Pages 1029-1032
    Published: November 05, 1981
    Released: August 05, 2011
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  • Tomio Senda
    1981 Volume 50 Issue 11 Pages 1033-1034
    Published: November 05, 1981
    Released: August 05, 2011
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  • Keiji Yokoyama
    1981 Volume 50 Issue 11 Pages 1035-1037
    Published: November 05, 1981
    Released: August 05, 2011
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  • Shigeru Miyoshi
    1981 Volume 50 Issue 11 Pages 1037-1041
    Published: November 05, 1981
    Released: August 05, 2011
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  • Kazuo Hirayama
    1981 Volume 50 Issue 11 Pages 1042-1048
    Published: November 05, 1981
    Released: August 05, 2011
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  • Sadao Hirose, Hiroshi Uragaki
    1981 Volume 50 Issue 11 Pages 1049-1056
    Published: November 05, 1981
    Released: August 05, 2011
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  • Koichi Akizono
    1981 Volume 50 Issue 11 Pages 1057-1058
    Published: November 05, 1981
    Released: August 05, 2011
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  • Nobuyuki Yamauchi, Kazuo Agusa
    1981 Volume 50 Issue 11 Pages 1059-1065
    Published: November 05, 1981
    Released: August 05, 2011
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  • Kazuo Agusa, Nobuyuki Yamauchi
    1981 Volume 50 Issue 11 Pages 1066-1074
    Published: November 05, 1981
    Released: August 05, 2011
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  • Itsuhiko Sejima, Tomokazu Godai, Minoru Kawahara, Hirokazu Nomura
    1981 Volume 50 Issue 11 Pages 1074-1080
    Published: November 05, 1981
    Released: August 05, 2011
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  • Tsugihiko Satoh, Jyoichi Katayama, Seigo Kodama
    1981 Volume 50 Issue 11 Pages 1081-1088
    Published: November 05, 1981
    Released: August 05, 2011
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    As a part of investigation on the fatigue strength of multi-spot welded joints arranged in perpendicular to load direction, plane stress distributions of single- and multi-spot welded joints were studied. The purposes are to make clear effects of specimen width and/or lap length on stress distribution of single-spot welded joint and of spot space and/or lap length on that of multi-spot welded joint. Moreover, it was intended to find out a relationship between plane stress distributions of single- and multi-spot welded joints.
    First, qualitative studies of stress distribution on line (the X-axis in Fig. 1) including nugget front where fatigue crack may generate were carried out. Second, based on the above qualitative studies, quantitative studies of stress distribution by means of finite element method were carried out. Main conclusions obtained in this investigation are as follows:
    (1) Effects of specimen width and/or lap length on stress distribution of single-spot welded joint were made clear.
    (2) Effects of spot space and/or lap length on stress distribution of multi-spot welded joint were made clear.
    (3) Effects of specimen width on stress distribution of single-spot welded joint and of spot space of the same length on that of multi-spot welded joint are equivalent, as long as ratio of specimen width of single-spot welded joint or of spot space of multi-spot welded joint to nugget diameter is not extremely small.
    (4) If the stress distribution (σy on the X-axis) of single-spot welded joint with sufficiently large specimen width is known, it is possible to estimate. approximately stress distributions of single- and multi-spot welded joints with different specimen widths or spot spaces but with the same lap length.
    (5) Moreover, if an applied load that either maximum stress of single-spot welded joint with some specimen width and lap length or of multi-spot welded joint with some spot space and lap length becomes a specific stress value is known, it is possible to estimate, by using the graph shown in Fig.12 (This figure shows the relationships between specimen width or spot space and load ratios, using lap length as parameter), a similar load for single-spot welded joint with any specimen width and lap length or for multi-spot welded joint with any spot space and lap length.
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  • Mutsuo Nakanishi, Seiichi Watanabe, Jun Furusawa
    1981 Volume 50 Issue 11 Pages 1088-1094
    Published: November 05, 1981
    Released: August 05, 2011
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    The creep cracking caused by the high temperature and high pressure environment has been reported in the welds of Cr-Mo steels used for the chemical reactor vessels. So the mechanism and prevention of creep cracking of Cr-Mo steel welds were investigated in connection with reheat cracking using the creep rupture test and the SERT test.
    From the observation of scanning electron micrographs of fracture surface and optical microstructures of fracture appearance, it is confirmed that the creep cracking could be simulated either by the creep rupture test or the SERT test. Therefore the susceptibility to the creep cracking can be evaluated from the reduction of area in the creep rupture test or the SERT test. And it is concluded that the susceptibility to the creep cracking of 1 1/4Cr-1/2Mo steel decrease with the combination of the stress relief treatment at high temperature, the decrease of carbon content and the reduction of copper and nickel.
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  • Isao Masumoto, Muneharu Kutsuna, Kozo Yasuda
    1981 Volume 50 Issue 11 Pages 1095-1101
    Published: November 05, 1981
    Released: August 05, 2011
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    One side welding joints of thick material are made by high power electron beam welding which is expected high quality, high welding speed, low heat input per unit joint area and small welding deformation. Big machinery goods, pressure vessels and penstocks are expected to be welded by high power, electron beam welding.
    This high power electron beam gun has beam characteristics of relatively wide beam diameter, low power density and long beam active zone in comparison with low power high voltage type electron beam gun.
    This report discusses the fundamental characteristics of high power electron beam welding and the results obtained in this study are as follows;
    1) Energy density of high power electron beam gun was up to 105×106 W/cm2 required to the characteristics of deep penetration, but beam diameter was increasing in accordance with increment of beam current and average beam energy density was almost constant level (about 2×106 W/cm2).
    2) Penetration depth of horizontal position was deeper than flat position but it was in proportion to the square root of heat input per unit length.
    3) Melting zone of welding cross section was in proportion to the heat input per unit length.
    4) Influence of vacuum condition on penetration depth was large for high power electron beam gun of low average beam energy density in comparison with high average beam energy density electron beam gun.
    5) The melting efficiency of high power electron beam welding was about 32%.
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  • Yoshikuni Nakao, Takeshi Nishiyam
    1981 Volume 50 Issue 11 Pages 1102-1107
    Published: November 05, 1981
    Released: August 05, 2011
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    The effects of grain size and impurity elements on an intergranular crack initiation stress at 600°C were investigated to clarify the mechanism of reheat cracking. Two kinds of steels were used, one was crack sensitive A387-12, the other one was insensitive A533B-Class 1.
    The results obtained in this study are, as follows;
    1) There is a linear relationship between intergranular crack initiation stress at 600°C and inverse square root of grain size.
    The stress increases with decreasing grain size.
    2) In case of same grain size, the stress decreases with increasing content of phosphorus or antimony.
    3) Phosphorus or antimony influences the effective surface energy to nucleate or propagate intergranular crack. The energy is lowered by increasing content of phosphorus or antimony.
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  • Yoshikuni Nakao, Kazutoshi Nishimoto, Syoji Inoue
    1981 Volume 50 Issue 11 Pages 1107-1111
    Published: November 05, 1981
    Released: August 05, 2011
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    As reported in the previous work, the formation of Widmanstatten austenite at constant temperature in Type 329J1 duplex stainless steel can be expressed by Austin- Rickett's type equation.
    In this report, the method for calculation of austenite amount formed during thermal cycle was considered, based on this equation. The validity of this method was examined in synthetic heating and cooling thermal cycle process. Subsequently, this method was applied for the formation of austenite in HAZ. As the result, it was experimentally confirmed that the amount of austenite in HAZ could be calculated using this method.
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  • Shuji Nakata, Naoki Ooshiro
    1981 Volume 50 Issue 11 Pages 1112-1118
    Published: November 05, 1981
    Released: August 05, 2011
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    Direct current flash welding phenomena and the control of flashing characteristics by inserting the electric condenser in parallel with specimen were studied experimentaly in the single phase direct current flash welding process using thin sheet of low carbon steel and stainless steel.
    It is shown that in single phase-full wave direct current flash welding process, the flashings with large current often occur near the phase of the voltage being zero in terminal of the welding transformer and the maximum values of these fashing current are 3-6 times of those near the maximum phase in terminal voltage as similar as those in alternate current flash welding process.
    But, by inserting the electric capacitor with high capacity in parallel with specimen, flashing became more fine and continuous at not only the neighberhood of zoro value but that of peak value in terminal vlotage. These phenomena are caused by feeding enough large current at very short duration to break and burn off the contact part in abutting specimen end by charged capacitor, and furthermore, the effective inductance in the welding power source can be adjusted to decrease to small value by conecting the capacitor.
    Thus, it is confirmed that the degree of concaves at abutting ends of specimens decrease by fine and continuous flashing, and, as the result, the flash welded joints with good mechanical property are obtained easily.
    Furthermore, it is confirmed experimentaly that the polarity effect on the amount of specimens burned off by flashing is small in direct current flash welding process, that is, the difference of the amount flashed off in anode and cathode is nearly 10%.
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  • Katsunori Inoue
    1981 Volume 50 Issue 11 Pages 1118-1124
    Published: November 05, 1981
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    It is possible to improve the visual information, which is obtained from the arc welding process, by taking the wavelength spectrum into consideration.
    In the first stage of this paper, the spectrum of welding arc and molten pool is measured with a grating monochrometer. This measurement indicates that CO2 arc, Ar arc and molten pool have their characteristic spectrum respectively.
    The images of the arc welding process are improved and the configuration of the molten pool is relatively emphasized by selecting the image pickup device and the optical filter on the basis of the spectrum characteristics in the next.
    The bead width and the penetration depth are measured by digital processing of these images in real time in the final stage and the results of measurement agree well with the actual bead width and penetration depth.
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  • Hirosada Irie, Tatsuya Hashimoto, Michio Inagaki
    1981 Volume 50 Issue 11 Pages 1125-1129
    Published: November 05, 1981
    Released: August 05, 2011
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    The melting process of solid metal by an electron beam during the electron beam welding under steady state was investigated and discussed from the microscopic point of view. The melting process progresses not continuously, but intermittently, which contains three kinds of occurrence frequency, that is, a few kHz component, the ripple frequency of the high voltage power source and the intrinsic melting frequency depending upon the electron beam property (power density distribution). In the conventional high power electron beam welding, however, the welding phenomena are influenced strongly by both the ripple variation of the power source and the intrinsic melting process. The spiking phenomenon depends not only the intermittent melting process but also the state of molten metal in the beam hole and inhomogeneity of the metal. The possibility of suppression of the spiking phenomenon was also discussed.
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