JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 36, Issue 2
Displaying 1-8 of 8 articles from this issue
  • 1967 Volume 36 Issue 2 Pages 92
    Published: 1967
    Released on J-STAGE: August 05, 2011
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  • Ken Ocho
    1967 Volume 36 Issue 2 Pages 100-115
    Published: February 25, 1967
    Released on J-STAGE: August 05, 2011
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  • Kazuhisa Suzuki, Toshikazu Shimoyama, Toshihiro Hamada
    1967 Volume 36 Issue 2 Pages 116-131
    Published: February 25, 1967
    Released on J-STAGE: August 05, 2011
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  • Kohei Ando, Kimiyuki Nishiguchi
    1967 Volume 36 Issue 2 Pages 132-139
    Published: February 25, 1967
    Released on J-STAGE: August 05, 2011
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    Arc welding conditions are discussed for a mother plate which is n times as large as and geometrically similar to the original plate. From the theory of heat conduction, it easily follows that the temperature of the geometrically similar point is equal if we select the values of current, effective arc voltage for heat input, welding velocity and time as n, 1, 1/n and n2 times those of the original plate, respectively.
    This is based on the assumption that the current distribution in the arc obeys the law of similitude which holds in metal conductor parts. It is well known that the melting rate of welding rod is proportional to the current and the heat input to the base metal is also proportional to the current and is independent of arc voltage when we neglect the heat from the arc column. However the relation of similitude fails when we consider the phenomena in welding arc, i.e., the electromagnetic pinch effect, plasma stream, surface tension and convection in the molten pool. Some discussions on each theme are described.
    From the standpoint of heat conduction, we presume that the welding speed as well as the welding current should be much larger in aluminum compared to steel. However the practical recommended conditions contradict the presumption above mentioned. It is well known in practise that the tendency of finger type penetration is very strong in aluminum. This is based on the reason that the liquid pressure which counteracts the digging action due to arc is much smaller in aluminum owing to its smaller specific density compared to steel.
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  • Tensile relaxation test of HT 60 and deposited metal
    Zinkichi Tanaka, Tadayoshi Obata
    1967 Volume 36 Issue 2 Pages 140-145
    Published: February 25, 1967
    Released on J-STAGE: August 05, 2011
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    In order to study the effect of stress relief heat treatment quantitatively, tensile relaxation test and short-time high temperature tensile test were carried out using HT60 and deposited metal. High temperature tensile test was done to measure the stress-strain curve, Young's modulus and yield strength or proof stress at high temperature. The relaxation conditions were as follows; Initial stress 45 Kg/mm2 and 25 Kg/mm2, relaxation temperature 500°C-650°C, holding time at relaxation temperature 2 hours.
    The relaxation test results were discussed on the basis of high temperature tensile test data and discussion is summarized as follows,
    I During heating process, residual stress decreased in accordnace with the temperature-rise due to temperature dependence of Young's modulus and conversion of elastic strain to plastic strain. Residual stress, at the instant when the temperature of specimen reached relaxation temperature, was lower than the stress which was obtained from stress-strain curve at the same strain amplitude as relaxation condition. The difference between experimental and calculated stress increased as relaxation temperature rose and as initial stress increased.
    2 In the holding period at relaxation temperature, residual stress decreased owing to creep. The reduction of stress became larger as initial stress was higher. The 2/3th of the total reduction of stress took place in the first period within 1 hour.
    3 The reduction of heating speed increased the reduction of stress during heating period and decreased it in the holding period. But after 2 hours, residual stress showed a constant value, independent of heating speed.
    4 The stress relaxation of deposited metal was much less than that of base metal and its high temperature strength was higher than that of base metal. But in this case, the structural change during relaxation test must be considered.
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  • Iwao Onishi, Ikuo Okamoto, Masaki Imachi
    1967 Volume 36 Issue 2 Pages 146-153
    Published: February 25, 1967
    Released on J-STAGE: August 05, 2011
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    The mechanical properties of adhesive joints of metals and the cured adhesive used in the experiment were examined. Mild steel, copper, aluminium etc. were used for the adherend but as an adhesive, the epoxy-adhesive was employed.
    The results are summarized as follows:
    1) As the curing process of adhesive advances, the adhesive strength increases bnd there is almost no change in adhesive strength after about 70 hours. In 6 months, the adhesive strength slightly decreases because of aging.
    2) In the case of narrow adhesive joint clearance up to 0.2 mm, the narrower the clearance is, the more the adhesive strength decreases. This is probably caused by the defects such as blowholes.
    3) In the tensile test, owing to the rise of temperature of atmosphere, the adhesive strength decreases remarkably and then at the low temperature below 0°C, there are some cases where the adhesive strength decreases.
    This tendency of the adhesive joint is similar to that of the cured adhesive, even if the fracture of the adhesive joint occurs at the adhesive-adherend interface.
    4) There was no significant difference in the adhesive strength among the various metals.
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  • Kunihiko Satoh
    1967 Volume 36 Issue 2 Pages 154-159
    Published: February 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The present report discusses on heat conduction in an infinite body in which a point heat source of intensity q (cal/sec) moves at a constant speed v along x-axis as shown in Fig. 1. The problem has been well known since Rosenthal reported a mathematical analysis in 1941. However, analysis in the present report shows that temperature at a point during cooling by a moving heat source is approximately the same as temperature when using an instantaneous line or plane heat source.
    For the three-dimensional quasi-stationary heat flow of an infinite body the temperature θ during cooling at a point P in Fig. 1 is approximately given by eq. (1) or the temperature θL under heating by an instantaneous line heat source of intensity q/v (cal/cm) along x-axis, in which c is specific heat, ρ is density, k is heat diffusivity and t is the time after the point heat source comes to the point O1 in Fig. 1.
    For the two-dimensional quasi-stationary heat flow of an infinite plate of thickness h the temperature θ during cooling at a point P is approximately given by eq. (2) or the temperature θp under heating by an instantaneous plane heat source of intensity q/vh (cal/cm2) on x-z plane.
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  • Properties of Welded Metal for 9%Ni Steel
    Toshikage Ikkai
    1967 Volume 36 Issue 2 Pages 160-168
    Published: February 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Performances of submerged arc welds by using a bonded flux experimentally produced for low temperature material (Aluminum killed steel, 35% Ni steel) were described in the previous report.
    Using the bonded flux experimentally manufactured for the purpose of achieving automatic welding of 9% Ni steel for lower temperature use (from -101°C to-196°C) use, the tests of tensile strength and impact vafue at low temperature of submerged arc welded metal have been conducted.
    The results obtained are summarized as follows:
    (1). Because the bonded flux H-900 for 9% Ni steel is low hydrogen type of mixture without SiO2 content it is somewhat poor in operating property, whereas the use of direct current reversed polarity results in good operating property and bead weld.
    (2) The mechanical properties of 9% Ni steel plate at -196°C were satisfactory : 100 kg/mm2 in tensile strength, 80 kg/mm2 in yield point, 20% in elongation and 6 kg-m in impact value. Accordingly, when designing equipments with this steel, it is possible to reduce its thickness considerably.
    (3) The mechanical properties of all deposited metal at -196°C are 87 kg/mm2 in tensile strength, 55 kg/mm2 in yield point, 30% in elongation, and 3.5 kg-m in impact value, all of which satisfy the standards at low temperature prescribed in ASTM.
    (4) The highest hardness of heat-affected zone is approximately 360 in Hv as welded, while it decreases to about 290 in Hv after stress relief annealing at 570°C for 2 hours. There is found no transverse crack of bead weld and no crack of heat-affected zone, but the non-removed crater leads to a development of crater cracks.
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