JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 27, Issue 6
Displaying 1-7 of 7 articles from this issue
  • 1958 Volume 27 Issue 6 Pages 307-312
    Published: June 25, 1958
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
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  • M. Watanabe, K. Satoh
    1958 Volume 27 Issue 6 Pages 313-320
    Published: June 25, 1958
    Released on J-STAGE: July 14, 2010
    JOURNAL FREE ACCESS
    Distortion due to welding is one of the most troublesome problems especially in welding of thin plate. The authors pointed out in the previous paper (M. Watanabe and K. Satoh; J. of J.W.S. Vol. 26 399/405) distortion in welding of thin plate is produced by buckling due to compressive thermal stress during welding. In this paper we studied on two fundamental problems for buckling of bead-on plate, that is to say, minimum half-wave length, below which a plate does not buckle, and maximum radius of curveture after buckling.
    Specimens used are rectangular steel plate of 700 mm long and 1.6 mm thick. In order to obtain time of buckling, deflections during cooling are measured by the apparatus as shown in Fig. 1, and the results are shown in Fig. 2. Deflection abruptly changes during cooling in moderately wide plate. It seems that plate buckles at this time, but in narrow plate abrupt change of deflection does not occur. For this case, the time of buckling was assumed as shown in Fig. 3. In order to obtain compressive thermal stress at the time of buckling longitudinal strain and temperature rise during cooling were measured. The results are shown in Figs. 5 and 6. Fig. 7 is an example of calculation of thermal stress at the time of buckling. Critical thermal stress σcr for each specimen is shown in Table 1.
    By considering the analogy betwcen buckling of an angle due to compression (Fig. 9) and buckling of bead-on plate, the critical inherent shrinkage is given by equation (4), in which k is a numerical factor dependent on aspect ratio L/B of the plate. k is represented by a linear function of (B/L)2 as shown in Fig. 10.
    Inherent shrinkage ξ1 due to welding, an example of which is shown in eq. (6), becomes to a critical value ξ1cr, then the plate buckles. If welding condition, and therefore inherent shrinkage, is constant, there is a minimum half-wave length or minimum weld length below which the plate does not buckle. In the case of panel specimen in Fig. 11, the minimum half-wave length is estimated about 190mm as shown in Figs. 12 and 13. Fig. 14 is minimum half-wave length of 1.6 mm thick plate for various breadth of plate and welding conditions.
    It has been already known that maximum deflection of buckled plate is linear to square of half-wave length. It implies that maximum radius of curveture is independent to half-wave length. Maximam radius of curveture for varius breadth of plate is shown in Fig. 15.
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  • S. Ito, K. Honda, K. Ishiyama
    1958 Volume 27 Issue 6 Pages 321-326
    Published: June 25, 1958
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    A study has been made of the severe wear of pearlitic steel weld metal, rubbing on itself, at a speed of 2.5cm/s under a load of 40kg, in unlubricated conditions.
    In this range of the test conditions, once equilibrium surface conditions are estabiished, the relation-ship W=KL/Pm is obeyed, where W is the wear rate, L is the load, and Pm is the flow pressure of the material.
    This values of K indicates the wear property of the weld metal.
    The relationship between wear property and micro structure or chemical composition is speculated. By the microscopical examinations of the wearing surface, it has been possible to from a picture of the movement of the wear debris.
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  • I. Ukita, S. Nobuhara
    1958 Volume 27 Issue 6 Pages 327-330
    Published: June 25, 1958
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    In recent years, the tungsten inert gas arc welding process superposing the high frequency current is being, more and more, used. According to this, it comes to the problem how the noise in the wireless fields, which is generated by the high frequency current, is decreased.
    In order to study fundamentally on this problem, we have set a vacuum tube high frequency oscillator. And we have investigatied the relations between the discharging voltage and frequency in the atomospheres of air and argon gas and in use of some shapes of electrode where the gap length is taken as parameter.
    The works performed are summarrised as follows :
    (1) Discharging voltage goes down to minimum value at about 800KC and 10MC in both atomospheres.
    (2) Discharging voltage in the argon atomosphere is about a third of that in air.
    (3) Remarcable influences of the rate of argon flow upon the discharging voltage are not found.
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  • Low Hydrogen Content and Frequency of Fisheye Occurrence of Weld Metal
    H. Sekiguchi, I. Masumoto
    1958 Volume 27 Issue 6 Pages 331-339
    Published: June 25, 1958
    Released on J-STAGE: December 10, 2009
    JOURNAL FREE ACCESS
    From the results of the determinations of hydrogen, nitrogen and oxygen contents of the weld metals obtained by the various welding processes, the authors recognized the following facts:
    1. In comparison with the argon-metal-arc, the submerged arc and the manual arc welding with two types of coated electrodes, the C. S. arc welding gives a weld with the smallest content of hydrogen.
    2. It is deduced that the shielding effect of thesupplied gas in case of the C. S. are welding process is the same degree as well as the argon-metal-arc and the submerged arc welding processes, because the nitrogen content of the weld metal by the former process is the same degree as the latter.
    3. A manual arc welding with a low hydrogen type electrode has the poorest shielding effect, because it gives a weld with the largest nitrogen content in comparison with the other welding processes.
    4. The total oxygen content of weld increases with welding process in order as follows ; the argon-metal-arc, the C. S. arc, the manual arc with a low hydrogen type electrode, the one with a ilmenite type electrode and the submerged arc welding.
    Then the authors clarified experimentally the relation between the dew point of supplied gas and the hydrogen content of weld by the C. S. arc welding, and the fact that the hydrogen content increases steeply with the increment of the dew point of the supplied gas over-10°C. And the ductility of the weld metal, obtained by the shielding with the gas having such a high dew point, is lower than the one with the gas having a lower dew point.
    Moreover, the authors showed that the moisture in a conduit and the rust on an electrode increases the hydrogen content of the weld by the C. S. arc welding process. If the sufficient attention is paied on such points, i.e., if the dried gas and conduit and a rustless electrode are used, the C. S. arc welding gives a weld having the lowest hydrogen content in comparison with all other arc welding processes.
    Accordingly, the C. S. arc welding showed also a very low frequency of fisheye occurrence, which is due to hydrogen in weld metal, on the fracture of tension test specimen. This was ascertained experimentally by many tension tests in comparison with the manual arc welding using a low hydrogen or an ilmenite type electrode.
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  • On 46 and 49kg/mm2 mild steels
    H. Sekiguchi, M. Inagaki
    1958 Volume 27 Issue 6 Pages 340-346
    Published: June 25, 1958
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    In this report, the continuous cooling transformation diagrams in case of maximum heating temperature 1350°C, being convenient to estimate the strurture and hardness of the heat-affected zone near the fusion line by welding, were constructed for two kinds of steels of which ultimate tensile strengths are 46 and 49kg/mm2. The continuous heating austenitization diagrams of those steels were also constructed. And, the following results were obtained;
    1. For the steel having ultimate tensile strenght of 46kg/mm2, of which A3-transformation-point is 829°C and A1- point 720°C, critical cooling times, from A3-point to 500°C, are determined as follows ;
    Cz'=1.25sec, Cf'=2.3sec, Cp'=9.0sec & Ce'=275sec, and the cooling time corresponding to 50% martensite is 3.8sec.
    2. For the steel having ultimate tensile strength of 49kg./mm2, of which A3-point is 824°C and A1-point 702°C, critical cooling times are determined as follows ;
    Cz'=1.35sec, Cf'=3.2sec, Cp'=19sec & Ce'=280sec, and the cooling time corresponding to 50% martensite is 7.5sec.
    That is, concerning to the examples in this report, the values of critical cooling times of the steel having higher ultimate tensile strength are larger than those of the one having lower ultimate tensile strength.
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  • T. Nakamura, E. Maeda
    1958 Volume 27 Issue 6 Pages 347-353
    Published: June 25, 1958
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    In this paper, the purpose of this investigation was to study the characteristics of spot weld in commercially pure Ti and its fatigue strength when used for three phase frequency converter type spot welder. We studied the spot weld results in shear strength, indentation, macro section and fatigue strength etc. by changing some welding variables. Results obtained are as followes ;
    (1) The influence of welding current and heat time on spot weld are very significant.
    (2) The influence of weld pressure was little observed.
    (3) Indentation are very small when used for three phase converter type spot welder.
    (4) No defect is produced for wide heating range.
    (5) The fatigue limits of spot weld in commercially pure Ti are somewhat higher than for similar joints in Alclad 24S-T alminum alloy.
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