JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 49 , Issue 3
Showing 1-9 articles out of 9 articles from the selected issue
  • J.J. Chéne
    1980 Volume 49 Issue 3 Pages 163-171
    Published: March 05, 1980
    Released: August 05, 2011
    JOURNALS FREE ACCESS
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  • Tomio Senda
    1980 Volume 49 Issue 3 Pages 171-177
    Published: March 05, 1980
    Released: August 05, 2011
    JOURNALS FREE ACCESS
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  • Itsuro Tatsukawa, Sei-ichi Inoue, Haruhiko Akiyoshi
    1980 Volume 49 Issue 3 Pages 178-183
    Published: March 05, 1980
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    An experimental study is made on the formation of stress and distortion in argon-shielded GTAW of butt joints of nonheat-treatable Al-Mg alloy plates. Measurements are made of the changes in temperature, transverse distortion and restraint stress during welding unrestrained or H-type restrained V-groove joints of 6 mm thick plate. In addition, the longitudinal residual stresses and distortion as well as the temperature distributions are observed for groove welds of 10 mm thick plates.free from external restraint. The results obtained can be summarized as follows:
    1) The shielding gas flow accelerates cooling of the surface layer in the deposited metal and the surrounding base metal area, and has influence on the angular distortions of weld.
    2) The transverse thermal expansion of base metal that occurs during welding reduces the root gap, consequently promoting the transverse shrinkage. In the restrained welds, compressive restraint stress is produced at the initial stage of cooling process, and afterwards changes to shrinkage stress, the magnitude of which eventually reaches near the proof stress of the heat-affected base metal.
    3) The longitudinal dimensional change of base metal that occurs during welding according to the nonuniform temperature change in it causes rotational distortion, which gives occasion to longitudinal hot cracking near the starting-point of weld bead.
    4) The longitudinal plastic shrinkage produced at the weld area is greater at the bottom surface than at the top surface subjected to shielding gas flow, and induces longitudinal angular distortion convex at the top side.
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  • Shigetsugu Asakura, Masayasu Nihei, Hiroshi Wachi
    1980 Volume 49 Issue 3 Pages 184-190
    Published: March 05, 1980
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    The weld heat-affected zone notch toughness of 13Cr cast steels containing Ni (13Cr-Ni) and containing Ni and Mo (13Cr-Ni-Mo) were examined by the welding heat cycle simulating method. The results of these tests are summarized as follows.
    (1) When the heat cycle above Ac3 point is applied, the lower the cooling rate in the range from Ms point to Mf point, the more the impact value increases in 13Cr-Ni cast steel.
    (2) The lower the interpass temperature and the holding temperature before starting postheating in the range from the Ms point to the Mf point, the more the impact value increased for both 13Cr-Ni and 13Cr-Ni-Mo cast steels.
    (3) The impact value was considerably affected by peak temperature of the subsequent heat cycle or postheating temperature which corresponded to tempering of the martensite caused by the proceding heat cycle above Ac3 point. In 13Cr-Ni cast steel, when these temperature were around 650°C, temper brittleness occurred.
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  • Yoshihiko Mukai, Masato Murata
    1980 Volume 49 Issue 3 Pages 191-197
    Published: March 05, 1980
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    Crack propagation features of stress corrosion cracking (SCC) of type 304 stainless steel in 42 % MgCl2 solution were studied in a ream of our papers and it was made clear that crack growth rate was respresented well using the following equation.
    da/dt=C(Ke/2ff-KI/2scc) C:const …………(1)
    {da/dt : Crack growth rate
    K : Stress intensity factor
    KISCC : Threshold stress intensity factor in SCC
    In the present paper, crack propagation behavior of SCC in residual stress field in welded joints was predicted by the following integrated form of equation (1), as an example of application to nearly practical problem.
    t= ∫ da/C(K2-K2ISCC) …………(2)
    K in arbitrary crack length in welded joint was calculated by method of superposition. And the integration mentioned above can be done easily by Simpson's integration with computer. Now, SCC which was occured in actual welded joints would be more complicated, because crack morphology were not always single crack. It's almost analytically impossible to obtain strict solution for K in the case of irregular or branching cracks, so that, above all, evaluation of K in branching crack would be the most important problem to simulate the crack propagation behavior of SCC by means of computer. This problem was settled by defining the maximum mean value of K, K*eff, for branching crack as a new simplified quantative analysis method. By this method, a certain safety factor was considered in the step of calculation of K, and that it's useful from the standpoint of design, although the accuracy of solution deceases. ceases.
    As the results, when the residual stress distribution in no crack plates has already known, crack propagation behavior of SCC could be predicted by numerical analysis of equation (2). Namely, crack length in arbitraly time and arresting point of crack by decreasing of potential energy in system, or welded joint, could be predicted in the range of practically permissible error.
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  • Hirosada Irie, Tatsuya Hashimoto, Michio Inagaki, Yoshiaki Arata
    1980 Volume 49 Issue 3 Pages 197-203
    Published: March 05, 1980
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    Comparing energy densities between two electron beams, one of which penetrated through a metal and the other experienced no collision with metal, the state of electron beam in a beam hole was examined.
    The wall-facusing effect can be recognized in a simulated beam hole of solid wall made of molybdenum.
    The energy density of electron beam which practically drills a beam hole in a steel or an aluminum alloy plate decays by an interaction with metal vapors and metal. Even in this case, however, the decadance of energy density is weakened by the wall focusing-effect under a certain condition.
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  • Takeshi Matsuzaka, Seishin Kirihara, Isao Masaoka, Takatoshi Yoshioka
    1980 Volume 49 Issue 3 Pages 203-207
    Published: March 05, 1980
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    Effects of hardness and impurity contents of base materials on stress relief cracking susceptibility of 2 1/4 Cr-1Mo steel welds were examined. The results are summerized as follows;
    1) Stress relief cracking susceptibility was increased with increasing of base material hardness.
    2) Stress relief cracking susceptibility was increased with increasing of X=(l0P+5Sb+4Sn+As)/100.
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  • Yoshiaki Arata, Katsunori Inoue, Yutaka Shibata, Mitsuo Tamaoki, Haruh ...
    1980 Volume 49 Issue 3 Pages 208-213
    Published: March 05, 1980
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    The relation between welding conditions and the bead formation results are experimentally clarified and a method of the automatic setting of the suitable welding conditions by digital computer are discussed, on the horizontal narrow gap welding.
    The main results obtained are as follows:
    1) The formula by which weld bead height is given as the function of two parameters, that is, welding speed and current, was derived and its propriety was verified experimentally.
    2) The experimentally obtained weld beads were divided into three classes on the basis of their configuration. They are evaluated by their flatness factor, smoothness factor and symmetry factor. The domain in which the bead situation is satisfactory was established in the three dimensional space of groove width, welding speed and welding current.
    3) The method to set the suitable welding condition automatically by computer on considering the conclusions of (1) and (2) was proposed. The constant bead height and the satisfactory bead configuration will be obtained by adjusting welding speed and welding current according as the change of the root gap in this method.
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  • Kyoichi Murakami, Masakazu Ikeuchi, Akio Nishioka, Wataru Kawahara
    1980 Volume 49 Issue 3 Pages 213-219
    Published: March 05, 1980
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    The effect of aging treatment at 350-850°C on impact properties and microstructures of two-phase stainless steel and its heat affected zone have been investigated.
    The relation between impact properties and microstructural changes have been clarified. Results obtained are summarized as follows;
    1) Impact properties of aged two-phase stainless steel are strongly concerned with 475°C embrittlement and σ phase embrittlement. For each embrittlement impact properties are clearly related to hardness changes.
    2) For σ phase embrittlement a toughness dip of base metal is equal to that of its heat affected zone. The main reason is that σ phase precipitates with γ phase.
    3) For 475°C embrittlement. impact properties of base metal are different from that of its heat affected zone, because of the difference of α-grain size.
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