JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 33, Issue 7
Displaying 1-7 of 7 articles from this issue
  • Hiroshi Tamura, Masao Ishiwara
    1964 Volume 33 Issue 7 Pages 486-497
    Published: July 25, 1964
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • 1964 Volume 33 Issue 7 Pages 498-512
    Published: July 25, 1964
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Masaki Watanabe, Kunihiko Satoh
    1964 Volume 33 Issue 7 Pages 513-523
    Published: July 25, 1964
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    It is well known that reaction stresses of weldments produced during cooling under external restraint will be one of the serious factors affecting on weld cracking particularly on cold cracking. That is the reason why various types of restrained specimen have been used for weld cracking test. Reaction stresses in these specimens will be changed by the two factors ; the one is the relative rigidity of weld metal to restrained specimen and another is free contraction due to welding. Weld cracking test results may be influenced by the rigidity of specimen used even if the same conditions of materials and heat input are used. Therefore, it will be important for the evaluation of weld cracking test results to obtain informations on the rigidity of cracking test specimens.
    In order to consider the rigidity of restrained specimens, restraint coefficient was used, the definition of which is such that the restraint coefficient is equal to average value of transverse stress along weld line necessary to produce average elastic change of root gap of unit magnitude along the weld line. The restraint coefficient thus defined will be calculated with elastic theory for restrained specimens of simple shape, however, the calculation will be difficult for more complicated specimens and practical welded joints. For the measurements of restraint coefficient a new apparatus called "Restraint Meter" was designed by the authors. Principle of the restraint meter is that separating force is applied to both beveled edge planes of a weld groove before welding by the action of a wedge pushed into the groove and then the change of root gap is measured with displacement gauges. The separating force per unit change of root gap will be increased with the increase of rigidity. The restraint coefficient can be obtained from the separating force.
    Measurement of restraint coefficient by the restraint meter was performed for various cracking test specimens such as Lehigh type, N.R.L. type and Tekken type, which is widely used in Japan. Restraint coefficient of Lehigh type specimens ranges between 33 and 75 Kg/mm2. mm for 75 mm weld length and 11 and 45 Kg/mm2. mm for 125 mm weld length. Tekken weld cracking specimen shows 59 Kg/mm2. mm restraint coefficient. Reftraint coefficient of N.R.L. type specimen is much smaller than the above two because a end of weld groove is opened. (See Column (4) in Table 1.)
    The restraint coefficient obtained has close relationship to reaction force due to welding by the equation
    R=phlΔl
    where R: reaction force due to welding
    p: restraint coefficient
    h: thickness of plate
    l: weld length
    Δl: average elastic dislocation along weld line
    The relationship was confirmed for Lehigh cracking test specimens as shown in Table 2. (See Columns (5) and (8) in Table 2.)
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  • Yoshihiko Sugiyama
    1964 Volume 33 Issue 7 Pages 524-532
    Published: July 25, 1964
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Recently a new type of MIG welding torch, so-called a spool-on-gun torch has been developed in Japan. This study has been made to put this torch to practical use for welding thinner aluminum alloy sheets which cannot be welded by the conventional MIG welding torch. First the welding parameter guides in all positions for making butt and fillet joints of the thicknesses from 1 to 3 mm were chosen. Because of its smooth feeding of fine wires this type of torch facilitates the welding of thinner materials to which an ordinary push type manual torch has not been applicable. The useful minimum sheet thicknesses by this torch are seemed to be 0.8 mm in a butt joint and 1.6 mm in a tee joint respectively. This process is also applicable to all position welding at nearly the same welding condition as in the flat position. Welding speed by this process being faster than by TIG process, this process may be an effective joining method for aluminum to minimize welding distortion and to prevent the loss of mechanical properties caused by welding heat. The hardness survey for welds showed that the heat affected zones in MIG welds usually narrower than in TIG welds and consequently the joint effeciencies of undressed MIG welds were superior to those of TIG welds but without reinforcement they behaved adversely possibly due to a lot of fine porosities in weld metal made by this process.
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  • Measurement of Micro and Macro Residual Stress
    Toru Yoshida, Kikuji Hirano
    1964 Volume 33 Issue 7 Pages 533-537
    Published: July 25, 1964
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    In the measurement of residual stress in weldment carried out with use of Kα doublet diffraction, it is often difficult to determine the position of the diffraction peak exactly so far, because of the component lines of the doublet spaced so closely and of the their broadening occurring often in welded specimens. Here a method is presented to alleviate the difficulty, where the double diffraction patterns are separated to their single component profiles by means of a simple numerical calculation. While it facilitates the more exact determination of the diffraction peak and therefore of the macro scopic residual stress level, it facilitates the quantitative determination of the broadening of the diffraction profiles with a reasonable precision, too. Thus it becomes possible to draw into account the problem of estimating microscopic residual stress level therefrom, and therefore a mathematical scheme possibly useful for the practical analysis of experimental results and for the physical interpretation is presented also.
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  • Residual Stress of Butt-Welded Mijd Steel
    Toru Yoshida, Muniji Kato
    1964 Volume 33 Issue 7 Pages 538-543
    Published: July 25, 1964
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Study was undertaken in an attempt to measure the residual stresses in weld, where the effects of rolling residual stress in specimen, rate of cooling and rigidity of clamping were investigated. Two types of stress were measured ; i) the macroscopic residual stress indicated by shift of diffraction peak and ii) the microscopic residual stress indicated by broadening of diffraction profile. In welded specimens of as-rolled mild steel macroscopic residual stress was higher by the level of the macroscopic rolling residual stress than in welded specimens of annealed plate ; if specimens were cooled in water immediately after welding, the maocrscopic residual stress was increased by thermal stress of cooling ; and if specimens clamped in welding, the macroscopic residual stress in bead was higher than in specimens not clamped. Meanwhile, the microscopic residual stress value was monotonically decreased in welded specimens of annealed plate, as the point of measurement get farther from the bead ; however, in specimens of as-rolled plate, microscopic residual stress value, observed once to decrease from its maximum value at the center of the bead in the heat affected zone about the bead locally, was observed to increase somehow again thereafter until the value of the microscopic rolling residual stress level is attained in the farther part of specimen.
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  • Sadaaki Ekuni, Sadao Ishihara
    1964 Volume 33 Issue 7 Pages 544-552
    Published: July 25, 1964
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Authors studied about the shear-strength on brazed joints at the room and elevated temperatures, especially on the factors that affected on shear strength of brazed joints.
    Those factors were the strength of base metal, the kinds of brazing filler metals, the annealing after brazing, the thickness of filler metals in brazed joints and the roughness of filling surfaces.
    Base metals Selected the electric tough pitch copper and 0.45%C carbon steel, and ten filler metals selected from Ag-P-Cu, Ag-Cu-Cd-Zn and Cu systems. Specimens were used in a ring and plug type.
    The results of investigation were concluded as follows ;
    1. As to the filler metals which were stronger than base metals, the shear-strength of brazed joints of copper was nearly equal to that of base metals without relation to various filler metals.
    2. As to the base metals which were stronger than the filler metals, the shear-strength of brazed joints of steel was different with the filler metals.
    3. After annealing process had been adopted to brazed carbon steel joints, those shear-strength was dropped about 8-25%. When base metal was copper, its effect was negligible.
    4. The thickness of filler metals in brazed joints had no effect on shear-strength of brazed joints without relation to copper and stell.
    5. The smoothness of brazed surfaces had a slight effect on shear-strength, smooth surfaces in joints were better at shear strength than rough surfaces. The former's strength was 10% stronger than the latter's.
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