JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 18, Issue 6-8
Displaying 1-10 of 10 articles from this issue
  • Plastic Studies of Welded Joints, VIII
    M. Watanabe
    1949 Volume 18 Issue 6-8 Pages 97-102
    Published: 1949
    Released on J-STAGE: December 10, 2009
    JOURNAL FREE ACCESS
    In this report we dicussed, from the points of dynamics, the mechanisms of
    (a) Shrikage stress of the deposit metal itself.
    (b) Thermal stress of the mother metal caused by heating and cooling.
    (c) Transformation stress.
    The wave-figures of the deposit metal can be considered as a kind of isotherms of the deposit metal at the time of cooling. In the last report, we discussed the relation between a family of isotherms and constraing rate, and concluded that the maximum principal stcesses act in the tangential direction of isotherms. As the cracking is considered as a kind of bittle rupture which in practically not accompanied with deformation, the maximum principal stress theory will be applied to such a rupture. Indeed the cracks occur in the normal direction of the wave figures of the deposit metal. (Fig.1)
    Finally we an3lYsed the limiting curve for the cracking from the constraing rate and showed that this curve could be expressed by the formula i√v=const. or i2v=const. (Fig.4).
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  • Y. Kawakatu, T. Takeda, S. Dan
    1949 Volume 18 Issue 6-8 Pages 103-105
    Published: 1949
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    A new simple method is proposed of crackablity test of electrodes. The method is to check whether any crack is produced when two steel bars are welded together as shown in Fig. 1.
    A the result of the use of the above testing method has shown that the practical use of electrifies and our testing method produce the same result as the melthod adopted by the Railway Technocal Research Institute.
    We studied carefully to the relations of the quality of the steel bar to its diameter and the diameter of electrode as well as the cause of the crack.
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  • K. Nakamura, Y. Inagaki, S. Mizuno, K. Ishiyama
    1949 Volume 18 Issue 6-8 Pages 105-112
    Published: 1949
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    The term "usability" is used indefinitely by many welding operators, but the decision of the relative difficulty of welding is slightly different according to the operators.
    In this paper, we explain our view on the "usability."
    From the result of analysis of the usability of welding electrodes, we consider that the usability can be decided by 8 factors which are as follows :
    (1) stability of arc, (2) fluidity of slag, (3) *uniformity of melting, (4) penetration, (5) hardness of cleaning slag, (6) state of top of coated electrode in welding, (7) spattering, (8) slag-cvered state.
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  • Effect of Local Post-Heating on Cracks in the Welding-Heat-Affected Zone
    Harujiro Sekiguchi, Takuro Kobayashi
    1949 Volume 18 Issue 6-8 Pages 113-127
    Published: 1949
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    In this research, the correlation between cracks in the, heat-affected zone of alloy steels, welding conditions; the maximum hardness in the heat-affected zone and the local post-beating was investigated.
    In the first place, single beads were deposited on (8 mm thick) rectangular plates of alloy steel and the following facts were ascertained.
    (1) In the case of the 200 mm/min speed of bead-progress, if large diameter electrodes are used, large longitudinal cracks are apt to occur, and with small diameter electrodes small longitudinal cracks and transverse cracks are apt to occur.
    (2) In the case of 3.2 mm diameter electrodes, the larger the speed of bead-progress to is, the more difficult the occurrence of learge longitudinal cracks is and the easier th occurrence of transverse cracks is.
    (3) if the neighbourhood of a welded part is post-heated with a gas flame, both longitudinal and transverse cracks may be prevented.
    (4) But if the local post-heating is not performed in a suitable time after welding, good effect can not be expected.
    In the next place, the rectangular. specimen deposited with single beads and the special rectangular specimens having grooves slit in the center which were arc-welded, were cut perpendicular to the bead, and the hardness distribution on these sections was surveyed. Such procedures were also performed in the specimens which were deposited or welded and then post-heated. In this way, the following facts were found.
    (5) According to the hardness distribution on the above-mentioned section of specimens in which cracks did not occur, the maximum hardness is lower compared with those of-specimens in which cracks occurred.
    (6) If suitable heating is performed after welding, the maximum hardness in the heat-affected zone drops to a very low value, and cracks do not occur. But if the temperature and period of heating are not appropriate and consequently the softening of the hardened zone by welding is insufficient or on the contrary a new hardened zone appears again, the prevention of cracks is difficult. And even if post-heating is performed, when the time of heating after welding is not suitable, namely when it is after the occurrence of cracks, the good result can not be expected.
    In this manner, the relation between the maximum hardness of the heat-affected zone and cracks in the neighbourhood of this zohe, was claritied. Accordingly it is understood that if the maximum hardness is brought down to a suitable value by the local post-heating with sufficient means and cares, cracks can be prevent perfectly.
    But with the above-mentioned method, cracks in weld metals and unaffected parts can not be prevented.
    In order to prevent these cracks, other suitable methods are to be adopted.
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  • 1949 Volume 18 Issue 6-8 Pages 127b
    Published: 1949
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
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  • 1949 Volume 18 Issue 6-8 Pages 127a
    Published: 1949
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
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  • [in Japanese]
    1949 Volume 18 Issue 6-8 Pages 128-131
    Published: 1949
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    Download PDF (402K)
  • [in Japanese]
    1949 Volume 18 Issue 6-8 Pages 131-135
    Published: 1949
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    Download PDF (622K)
  • [in Japanese]
    1949 Volume 18 Issue 6-8 Pages 135-136
    Published: 1949
    Released on J-STAGE: December 10, 2009
    JOURNAL FREE ACCESS
    Download PDF (214K)
  • [in Japanese]
    1949 Volume 18 Issue 6-8 Pages 137
    Published: 1949
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    Download PDF (103K)
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