JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 36, Issue 8
Displaying 1-8 of 8 articles from this issue
  • Tomomichi Hotta
    1967 Volume 36 Issue 8 Pages 793-805
    Published: August 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Susumu Gohda, Makoto Sato
    1967 Volume 36 Issue 8 Pages 806-819
    Published: August 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Tsuguyasu Wada, Ken Sasabe, Makoto Tanabe
    1967 Volume 36 Issue 8 Pages 820-827
    Published: August 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The properties of brazed joint of titanium with silver-base filler metals have been examined, and an improvement of the filler metals has been made to find ones suitable for vacuum and inert-gas atmosphere brazing. It is found that the increase in the Cu-content of Ag-Cu filler metal increases the brittleness of the joint, the upper limit allowable being about 10% Cu. With electron-probe microanalysis, Cu in the brazement is found to be concentrated around the base metal/filler metal interface. By addition of Ni to the filler alloy, the microstructure of brazement is changed and the distribution of Cu becomes more uniform, resulting in an improvement of mechanical properties of the joint. The alloys Ag-15 Cu-3Ni and Ag-20Cu-3Ni are proved to give joints with satisfactory strength by vacuum brazing. The joints brazed in argon atmosphere by Li-containing Ag-Cu-Ni alloy show similar strength to that brazed in vacuum by Li-free Ag-Cu-Ni alloys.
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  • Hydrogen Embrittlement of Commercial Steels and their Weldments
    Iwao Onishi, Yoneo Kikuta, Takao Araki, Eitaro Kakimoto, Kooichi Harad ...
    1967 Volume 36 Issue 8 Pages 828-839
    Published: August 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The results of studies with respect to hydrogen embrittlement phenomenan have been reported by many workers and many hypotheses of that mechanism are advanced, but it seems that any unified opinion is not published.
    Then, in the study of that mechanism, it is significant to discuss about hydrogen-occluded steels under various stresses.
    From this point of view, this paper deals with the hydrogen embrittlment of commercial steels which are subjected to the constant load rupture test.
    Hydrogen was charged into steels cathodically under given constant loads (bath; 5% sulphric acid in poison phosphorus, charging temperature; R.T., current density; 0.08-0.09 amp/cm2, anode; platinum coil).
    The steels examined were carbon steels, chromium steels, stainless steels, 60 kg/mm2 class and 80 kg/mm2 class high tension steels, all commercial.
    This work discusses, using base material specimens and weld joint specimens of each steel, their susceptibility to hydrogen embrittlement.
    The results are summarized as follows:
    (1) The gradient of hydrogen embrittlement lines (relations between given stress and fracture time) for 80kg/mm2 class high tension steels are very steep and the stress range in which a hydrogen-delayed fracture occurs is very wide: 60 kg/mm2 class, carbon steels and chromium steel show in this order gentler slope and narrower stress range in which a delayed fracture occurs. Therefore, 80 kg/mm2 class high tension steels suffered most embrittlement and carbon steel did less embrittlemt. Stainless steel did not fracture by hydrogen.
    (2) High tension steel being affected by hydrogen, in the construction of high tension steels close attention must be paid to the problem of hydrogen embrittlement.
    (3) The susceptibility to hydrogen embrittlement of weld joint specimens was very different from that of each steel. High tension steel onffered most embrittlement which was more remarkable than in base material specimens. The fractured part mostly falls on bond and H.A.Z., for the welded part is affected easily by hydrogen.
    (4) When hydrogen-occluded steels were placed in a certain stress field, hydrogen cracks initiate at the defect and inclusion which exist already in steels and propargate. Propagation of hydrogen cracks is affected by the structure of matrix and the distribution of the lamination, but it needs more detailed microscopic analysis.
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  • Effect of temperature, concentration and pH of MgCl2 solution on induction period of stress corrosion cracking
    Masaki Watanabe, Yoshihiko Mukai, Akira Matuda, Kazuhiro Tunefuji
    1967 Volume 36 Issue 8 Pages 840-845
    Published: August 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    In the previous reports, we investigated the initiation of stress corrosion cracking in austenitic stainless steels by the boiling solution of 42 percent MgCl2 from the electrochemical standpoint. As the result of this research, we confirmed that the stress corrosion crack never occurs, unless the potential of test piece rises above the certain value determined by applied stress and material.
    In this report, we discussed whether the above conception with crack initiation potential obtained in the boiling solution of 42 percent MgCl2 is applicable to the case of stress corrosion cracking in the solution of different temperatures, concentrations or pH.
    When the temperature of solution was changed within the range of our experiment (from 120°C to 154°C), the induction period of stress corrosion cracking became long with a decrease of temperature of 42 percent MgCl2 solution. But the potential of test piece was constant in every case, when the stress corrosion crack occurred.
    On the other hand, when the concentration of MgCl2 boiling solution was changed within the range of our experiment (from 26.2 percent to 42.0 percent), the weaker the concentration, the longer the induction period was. But the potential for initiation of crack was constant.
    Moreover, when the pH of solution was changed, the potential was always constant at the time of crack initiation.
    Judging from the result obtained in this paper, it became clear that the necessary value of potential for the initiation of crack did not change at all with the variation of temperature, concentration and pH of MgCl2 solution.
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  • Welding of Low-Nickel Alloy Steel with Austenitic Electrode Wire
    Isao Masumoto, Kaneyuki Imai
    1967 Volume 36 Issue 8 Pages 846-853
    Published: August 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    As it was difficult to improve the impact value of weld metal to as high value as that of low nickel alloy steel base metal by addition of various elements, other improvements of the notch toughness of weld metal were experimentally examined by some heat treatments and by welding of low nickel alloy steel with austenitic electrode wires.
    (1) The more the fine grained structure increased in a low nickel alloy steel weld metal by multipass welding, the higher its impact value became.
    (2) The impact value of an as-welded metal of low nickel alloy steel was considerably improved by a heat treatment of normalizing from 900°C.
    (3) A post-weld low temperature annealing below A1 point lowered the impact value of 2 1/2% nickel steel weld metal. This is attributed to granularization of boundary cementite.
    (4) If low nickel alloy steel is to be welded by austenitic electrode wire to secure notch toughness of weld metal comparable to that of the base metal, the composition of the electrode wire must be so selected as to give a completely austenitic structure in weld metal, considering the dilution of base metal.
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  • Aging Characteristics of Heat-Affected Zone
    Masao Mizuno, Terumitu Takada, Shuichiro Katoh
    1967 Volume 36 Issue 8 Pages 854-861
    Published: August 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    A study has been made of aging characteristics of heat-affected zones in commercial Al-Zn-Mg alloy welds by means of hardness measurements. The work shows that in the material aged at room temperature the region where the temperature has reached 200°C and above during welding can be reversed, and the region heated to 140-200°C can be partially reversed. In this material the hardness of heat-affected zone can be fully restored by post-weld aging.
    In the material previously aged at 130°C for 24 hrs. the region where the peak temperature exceeds 300°C can be re-solution treated, and the region heated to 200-300°C can be partially reversed and remains the weakest part in the heat-affected zone after post-weld aging.
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  • Application of Series Spot Welding
    Toshio Yamamoto, Takio Okuda
    1967 Volume 36 Issue 8 Pages 862-868
    Published: August 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Experiment has been conducted on shunting current and tensile shear strength in series spot welding without back up bar (Series clad welding) and series projection welding which are considered as applications of series spot welding. And theoretical consideration is made about shunting current in twin spot welding. Further the effect of prewelded spot existing between electrodes on shunting current is discussed.
    As the result of experiment and consideration the following were concluded.
    (1) For a mild steel lower plate thicker than 3 mm, good welding results are obtained by series spot welding without a back up bar when an upper plate of stainless or mild steel is 0.5-1.0 mm in thickness.
    (2) Shunting current of series projection welding is about 20% larger than that of series spot welding.
    (3) When a prewelded spot exists between electrodes, upper and lower plate currents decrease or increase depending on the position of the prewelded spot, but the sum of upper and lower plate currents remains constant.
    (4) Shunting current of twin spot welding is 0.5-0.1 times as much as that of series spot welding.
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