Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 25 , Issue 8
Showing 1-9 articles out of 9 articles from the selected issue
  • A. Uchida
    1956 Volume 25 Issue 8 Pages 424-427
    Published: August 25, 1956
    Released: July 14, 2010
    A brief theoretical study has been attempted on the thermal distribution, heat transfer, Joule's heat of a MIG welding electrode wire, in the measured values of the burn-off rate of which there has been noted some discrepancies.
    The conclusion of the study is summarized :
    1) Under normal conditions for MIG welding, the thermal distribution curve of the wire begins on a mild gradient, independent of heat transfer, ending in a sharp rise near the tip.
    2) Accordingly, under these conditions (eAl0>>Aθ0-Bl0), the wire as viewed from the influence of thermal constants may be divided into two regions, namely, one independent of heat transfer effect (dependent on B/A) and the one, near the tip, in which the heat transfer effect prevails.
    3) Loss of heat transferred to the contact tube is proportional to the current, and is not influenced by the length of wire or the temperature of tip. But it has been found extremely small for all the metals.
    4) The contribution of joule's heat to the burn-off rate is estimated several % for aluminum and copper ; up to 10% for iron. Excepting such an alloy as stainless steel, its effect seems not to be an large.
    5) From these considerations, it can be concluded that, as major factors affecting the burn-off rate of the wire material quality and some yet unknown intricate mechanisms around the tip are suspected, besides the welding current and arc voltage.
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  • I. Onishi, M. Mizuno
    1956 Volume 25 Issue 8 Pages 428-432
    Published: August 25, 1956
    Released: June 12, 2009
    It is believed that the contents of hydrogen and nitrogen in the deposited metal made by the oxyacetylene flame are so small that the effect of these gases are very slight. This fact has been ascertained by authors by measuring the contents of these gases.
    1. Hydrogen : The analysis of the deposited metal for dissolved hydrogen was made by the Glycerine Method. As is shown in Fig. 3, the results of these analyses indicate that the amount of extracted gas from the deposited metal decreases as the mixed ratio (O2/C2H2) of the flame increases. This amounts, when compared with those obtained from arc welding (except the low-hydrogen type electrode), are much smaller. Table 1 gives the results of the hydrogen analysis (Vacuum Heating Extraction Method) of the metal deposited in the neutral flame. The hydrogen content decreases as the welding time increases.
    2. Nitrogen : The nitrogen content of the deposited metal melted under various conditions of the oxyacetylene flame using different filler rods is illustrated in Fig. 9. The nitrogen content increases as the mixed ratio of the flame increases. These nitrogen contents are nearly equal to or a little more than that of arc welded metal obtained from heavy coated electrode by melting it by arc. In the welding operation, the flame may introduce nitrogen from the air into the deposited metal. This tendency is recognized remarkably clear when the mixed ratio is increased and also when the filler metal with a smaller diameter is used.
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  • T. Kawamura, I. Okamoto, S. Hamada, Y. Fukuzono
    1956 Volume 25 Issue 8 Pages 433-437
    Published: August 25, 1956
    Released: June 12, 2009
    In the previous report, we tried tests of hardness, tension, bending and micro-structure and confirmed generation of so-called "Ferrite band" as the result of heat treatment in case of using the austenitic stainless steel electrode.
    In order to investigation this boundary defect, we tried tests of high temperature tension, temperature of generation of "Ferrite band" and corrosion in view of general use under high temperature.
    The results obtained were as follows;
    i) In the high temperature tention test of 4-6% Cr-1/2% Mo steel, in as weld they were broken down at the weld metal and in semi-soft anneal at the base metal in case of using austenitic stainless steel electrode.
    In case of using suitable compatible composion electrode, in semi-soft anneal they were broken down at the weld metal and in full anneal at the base metal, which show whether the heat treatment is proper or not.
    ii) In the test of 9% Cr-1% Mo steel, they were broken down at the base metal in any case.
    iii) The "Ferrite band" generated by heat treatment in room temperature test with austenitic stainless steel electrode did not apeared in high temperature tension test.
    iv) Indication of generation of "Ferrite band" begins to appear from the temperature over 500°C.
    v) The corrosion resisting property of "Ferrite band" is so decreased that it is corroded in 5% H2SO4 by boiling for only ten hours.
    It is worthy of special notice that the "Ferrite band" is corroded even in as weld.
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  • T. Ohwa
    1956 Volume 25 Issue 8 Pages 438-444
    Published: August 25, 1956
    Released: June 12, 2009
    Distribution of the toughness in the neighbour of weld, depending on the hysteresis and the directionality of the steel plate, are examined. Usability of the "Synthetic Impact Test Specimens" are considered. Max. brittle ratio of the heat-affected zone of the full-annealed steel plate seems to be greater than that of as-rolled steel plate. Synthetic impact values are greater slightly than the calculated one derived from the common impact method.
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  • T. Yoshida, W. Matsunaga, K. Terai, F. Kanaya
    1956 Volume 25 Issue 8 Pages 444-455
    Published: August 25, 1956
    Released: June 12, 2009
    Authors have made a study of the effect of the thicker plates urged by the need to solve the following constructional problem of 45, 000 DWT ore and oil carrier which our yard is planning of build.
    The construction of this ship as it is shown in the Fig. 1-Midship section, there is a large opening in the centre of upper deck. In this case, in way of supporting upper deck sectional area, there arose a question whether we shall adopt the doubling system which is usually applied to ore carrier, or boldly do away with the doubling plate and use extra thick plate instead. To be more in detail, if (a) two lines of doubling plates were passed on one side the plate thickness of upper deck would be sufficient by being 38 mm, but if (b) the doubling plates were limited to a single line then the thickness of plates requires to be 40mm and in case of (c) no doubler the thickness must be 47 mm.
    In consideration of the work in the spot, the compensation by the doubling involves a diffecult job. On the other hand, in consideration of the quality of steel and its weldability it seems more undesirable as the thickness of the steel plates become larger. As far as the thickness of the plates is concerned, there is not much difference in the effect 'between 38mm and 40 mm, so our consideration of the problem was focussed to whick should we choose, (b) or (c).
    The steel to be used for the purpose which came to our mind was C class steel of AB Rule, but when the thickness of steel becomes so large it is questionable whether we many obtain a suitable material that comes within the specifications of C class steel and a satisfactory joinability of the same time. So with a view to find out which possesses better joinability and the weldability for service, we made the following tests in order to make a comparative study between (b) and (c).
    1. Tension Test in room temperature.
    2. Standard V-Charpy Impact Test in the range of temperature -40°C to +60°C.
    3. Longitudinal Bead Bending Test (Kommerell Test) in the rang of temperature -60°C to +40°C.
    From these tests we could reach to the following conclusions.
    (1) According to the static tension test of both plates, of cf .Fig. 4, the normalizing will increase both yield strength and elongation, but gives hardly any effect to the tensile strength. (cf Fig. 5)
    (2) In the V-Charpy test, cf Fig. 6, the normalizing will lower 40 ft-1b transition temperature of the steel of both plates, but there was not hardly notceable of the effect to 15 ft-1b transition temperature. (cf Fig. 9) Generally 47mm thick plates, in comparison with 40mm thick plates, the notch sensitivity is somewhat larger, but the impact value in low temperature was sufficiently large when normalized. (cf Table 3 and Figs 7-13)
    (3) In the Kommerell test, cf Figs 14 and 27, both plates showed much larger bending angle than what is required under Austrian Welding Standard (cf Fig. 27). (cf Fig. 28). When low hydrogen electrode was used, the toughness of the weldments was very high, and even when the other types of electrode were used, if weldment was preheated it regained its toughness very noticeably. (cf Figs. 22-26)
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  • M. Watanabe, K. Satoh
    1956 Volume 25 Issue 8 Pages 455-460
    Published: August 25, 1956
    Released: December 10, 2009
    From the results of our previous paper (Report 1), the transverse shrinkage St in butt-welded joint is given by eq. (3), where w is deposited metal per unit weld length (gr/cm), w0 is deposited metal per unit weld length per one pass of weld (gr/cm), W is total deposited metal per unit weld length (gr/cm) (see Fig. 1), h is thickness of plate (cm) and C1 is a constant. C1 is proportional to (I/μα)(1/√φ), where I is welding current (Amp.), u is deposition efficiency of core, α is weight of melted core of electrode per unit current and unit time (gr/A. sec) and is diameter of electrode (mm). Trsnseverse shrinkage of first pass of Sto is given by eq. (5). I/μα depends on the welding conditions and W/h2 depends on the grove of butt-joint.
    The result of three series of experiments in Table 1 are plotted on the abscissa of log w. (see Figs. 2-4). Transverse shrinkage curse is decided by the following two factors :
    (1) Point of shrinkage of first pass {abscissa log w0
    ordinate St0=C0W/h2∞√I/μa√W/h2
    (2)Tangent of St-log w curve =2.302 C1(W/h2)∞(I/μa)(I/√φ)(W/h2)
    Transverse shrinkage is decreased by the increase of w0 and by the decrease of 1/μa, 1/√φ and W/h2. (see Figs 5-7).
    Angugar change is given by eq. (7) and Fig. 8. It is most affected by the type ob bevel of groove. Angular change is very small when deposited metal of top surface is about 60% of total deposited metal.
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  • A. Tsuruta, A. Minow, I. Funahashi
    1956 Volume 25 Issue 8 Pages 460-463
    Published: August 25, 1956
    Released: June 12, 2009
    Recently the large size fillet (L=19-25 mm) is used for building construction frequently. In generally, breaking strength of fillet is inclined to decrease in proportion as it's size inclease, but allowable stress of fillet is constant.
    Test was then made to study above mentioned point. The number of specimens were 29. Those specimens were devided into Front Fillet and Side Fillet Specimens, and each fillet's size were ranging from 10 to 25 mm.
    Test Result : Breaking strength increased compare with former tests. Breaking stress of large size fillet on both throat area, except or include penetration, were decreased. But average yield point on throat by Wire Straih Gauge were not various.
    Maximum stress, at first, distributed on outside of fillet, but at yield point and breaking point it changed on inside.
    We consider, then, the difference of strength by fillet size is due to the process from yield pt. to breaking pt. of fillet.
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  • Fred L. Plummer
    1956 Volume 25 Issue 8 Pages 464-468
    Published: August 25, 1956
    Released: June 12, 2009
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  • [in Japanese]
    1956 Volume 25 Issue 8 Pages 469-477
    Published: August 25, 1956
    Released: June 12, 2009
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