JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 43, Issue 12
Displaying 1-5 of 5 articles from this issue
  • Hiroshi Kimura, Takuji Yamaguchi, Masakazu Tsubokawa, Masaharu Toyoda
    1974 Volume 43 Issue 12 Pages 1174-1182
    Published: December 05, 1974
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    This paper describes an experimental study on the characteristics at low temperature of welded low density polyethylene. The results of some measurements on the mechanical properties, fracture surfaces, X-ray diffraction patterns and electron spin resonance spectra are reported and discussed.
    This study intends to clarify the low temperature characteristics of weld comparing with those of base material, and to discuss the change in mechanical properties from room temperature down to the neighborhood of -70°C and fracture in low temperature experiment from a microscopic view point. Nothc and load velocity effects on the brittle fracture tendency are also discussed. Testing materials were low density polyethylene board of 2mm. in thickness, and tests were carried out at low temperature of methyl alchohol and dry ice. A heat plate welding apparatus, with which specimens could be secured under fixed contact force, was made in order to carry out the experiment of welding.
    The following summary can be made of the experimental results. Tendency of low temperature characteristics of the welded material is generally similar to that of the base material, except that a change occurs at -60°C.
    Effect of load evlocity is observed both on the base and the welded materials, and this effect becomes great when the temperature is low and load velocity is high. Notch effect is also obsrved both on the base and the welded materials, and this effect appears great with the welded material under the temperature of below -40°C. Correlations are observed between fractured surface and mechanical testing results, as well as between X-ray diffraction pattern and mechanical testing results. No formation of non-coupling electron by welding is observed from electron spin resonance spectrogram.
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  • Applicaton to Welding of Boiler Tube
    Yoshiaki Arata, Iwao Futami, Kiyoshi Terai, Hiroyoshi Nagai, Shigeki S ...
    1974 Volume 43 Issue 12 Pages 1183-1193
    Published: December 05, 1974
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    In the previous paper. it was fully clarified that the electron beam welding process where the metal is inserted at the joint to be welded, that is, "Insert-type" electron beam welding process has a significant effect on "Uranami Welding", that is, root pass welding with smooth back bead and that the metallurgical and mechanical properties of dissimilar metal joints of 2 1/4Cr-IMo steel and austenitic stainless steel can be remarkably improved by the "Insert-type" electron beam welding.
    This paper discusses the problems involved when the "Insert-type" electron beam welding is employed for "Uranami Welding" of boiler tube, especially, those factors controlling be external and internal weld bead on the overlapped section between start and stop ends of the bead in circumferential welding and results of investigations on the joint characteristics of the welded section.
    Conclusions obtained may be summarised as follows;
    1) Defects noted at the weld bead of the overlapped section are concavities at the external weld bead; those found at the internal weld bead are concavities, excessive reinforcements and incomplete penetrations.
    2) Both the Ib' value, which is an assumed value of beam current being determined geometrically by the increase rate of beam current in starting a weld, that is, upslope rate, and the decrease rate of beam current in finishing a weld, that is, downslope rate and the downslope rate influence the defects at the internal weld bead of the overlapped section. Incomplete penetration appears invariably when the Ib' value is low, and an excessive reinforcement is apt too ccur when the Ib' value is too high. These defects do not ocur if the Ib'value is within a proper range. This proper Ib', value increases with an increase in wall thickness. Excessive reinforcement and concavity are apt to appear with an increase of downslope rate, even if the Ib' value lies in the proper range.
    3) Only the downslope rate influences singnificantly the extenal weld bead appearance of the overlapped section. 7.5mA/cm may be defined as the critical downslope rate regardless of the wall thickness of pipe used. Therefore, at the external weld bead of the overlapped section, the concavity defect appears intensively when the downslope rate is higher than the critical value.
    4) A starting point of downslope does not influence the internal weld bead appearance if the Ib' value is proper.
    5) Metallurigcal and mechanical proerties of the welded joint are quite satisfactory.
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  • Comparison with that of moving Point Heat
    Kohei Ando
    1974 Volume 43 Issue 12 Pages 1194-1204
    Published: December 05, 1974
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Temperature cooling rate is calculated for points near bead line in thin plate when linear heat source is applied instantaneuosly along all the range of bead whose length is l. Fig. 4 shows CR (cooling rate passing a definite temperature Ts) along the bead, and we see that CR at bead end is 4 times the bead center of infinite length. For the point whose distance from the bead end is 2 times ym, CR is 0.37 times the bead end. Here ym means the perpendicular distance from the bead, where the maximum temperature is equal to Ts, and ym is shown in equ. (45). Equ. (28) gives the relation of CR and temperature Ts, input heat q0.
    Fig. 9 shows the effect of bead length, and we see that for l>3ym, CR for the bead end is practically equal to that for l=∞, and for 1<1.5ym, CR is equal to that of the point heat whose heat is equal to q0⋅l.
    For a moving point heat source it is already shown that the temperatures of the starting as well as stopping bead end are just equal to half of that of the center, where quasi-stationary state is established. So the relation of CR for these points derived in case of infinite velocity holds well for a moving point heat source. For points equally distant from the bead ends, the literature (1) shows that CR for starting side is a little higher than that of stopping side. CR for infinite velocity has an intermediate value.
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  • Flux Action of variour Silves Salts and Copper Salts on Ni and Fe Plates
    Hiroshi Kihara, Ikuo Okamoto, Akira Omori, Shinji Kawasaki, Masaaki Mi ...
    1974 Volume 43 Issue 12 Pages 1205-1211
    Published: December 05, 1974
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    In previous paper, the flux action of various inorganic metal salts (chloride, sulfate and nitrate) for soldering was reported about the relation between the reaction of flux with molten Sn solder and spreadability of Sn solder on Cu plate.
    In this report, authors have studied the relation between the reaction of base plate (Ni, Fe) or Sn solder with flux and spreading phenomenon of Sn solder on Fe plate or Ni plate in the case of various silver salts and copper salts as flux.
    The results obtained were as follows:
    (1) The corrosion rate increases from Ni, to Cu and to Fe.
    (2) The effects of corrosion products on spreadability increased from FeCl3, to FeCl2, to NiCl2, and to CuCl2.
    (3) FeSn2 coated on Sn solder obstructs spreading of Sn solder.
    (4) FeSn2 produced by the reaction of molten Sn with Fe salt is controlled in proportion to the amount of Ag or Cu in Sn solder.
    (5) Spreading of Sn solder on Fe plate is affected by FeSn2 produced at interface of Sn solder and base plate.
    (6) When Ni plate is used, Ni dissolves little in Sn solder and spreadability depends on the reactivity of Sn with flux.
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  • Kunihiko Satoh
    1974 Volume 43 Issue 12 Pages 1212-1226
    Published: December 05, 1974
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Download PDF (892K)
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