JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 28 , Issue 8
Showing 1-8 articles out of 8 articles from the selected issue
  • [in Japanese]
    1959 Volume 28 Issue 8 Pages 496-502
    Published: August 25, 1959
    Released: June 12, 2009
    JOURNALS FREE ACCESS
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
    1959 Volume 28 Issue 8 Pages 503-510
    Published: August 25, 1959
    Released: June 12, 2009
    JOURNALS FREE ACCESS
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  • S. Hasebe
    1959 Volume 28 Issue 8 Pages 511-516
    Published: August 25, 1959
    Released: June 12, 2009
    JOURNALS FREE ACCESS
    The effects of aluminum content upon the properties of Mn-Si high tensile steel containing C 0.20%, Si 0.30%, Mn 1.40% as shown in Table 1 and 2 were studied. Mainly the effect of aluminum upon the underbead weld crack sensitivity was studied by CTS test and Battelle one.
    By the result of CTS test, the use of small or medium amount of aluminum (about 0.01% as acid soluble alumininum) was found to increase the underbead weld crack and the crack seemed to be reduced by either omitting aluminum or by using large additions as shown in Table 3 and 4.
    By the result of Battelle test, the crack fo the forged and normalized steels decreased as the aluminum content increased. The crack of the steels as casting seemed not to be much effected by the alumininum content and was much more sensitive for the crack than the forged and normalized steels as shown in Fig. 3.
    The addition of aluminum gave no change to the tensile properties of the forged and normalized steels except yield strength and decreased the elongation and area reduction of the steels as casting as shown in Fig. 4. The effect of aluminum upon the casting structure and non-metalic inclusion as casting was shown in Fig. 5 and 6.
    As stated above for Table 3 and 4, the effect of aluminum upon the underbead weld crack of Mn-Si high tensile steel seems to be complicated. This phenomenon has beed also indicated by C.E. Sims and others (literature No.4).
    The mechanism of the phenomenon that the crack is reduced by using large addition of aluminum is explained as the effect of aluminum carbide in steel. But the mechanism of the phenomenon that the crack is reduced by omitting aluminum or using very small additions does not seem to be explained. I studied about the possibility that the aluminium nitride would be effective to reduce the weldability of the steel containing both nitrogen and aluminum.
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  • H. Sekiguchi, M. Inagaki
    1959 Volume 28 Issue 8 Pages 517-524
    Published: August 25, 1959
    Released: June 12, 2009
    JOURNALS FREE ACCESS
    The continuous cooling transformation diagrams in case of maximum heating temperature 1350°C were constructed fo three kinds of rimmed-, semi-killed-and kliled-mild steel of which ultimate tensile strengths are 35, 42 and 49 kg/mm2. As the critical cooling times of those steels are generally remarkably smaller, it is difficult to construct those continuous cooling transformation diagrams. However, when the new apparatus for thermal analysis manufactured by the authors is used, the transformation tempe-ratures and the cooling curves can be determined accurately even in the case of cooling time from 800°C to 500°C being shotter than 1 sec. The following results were obtained:
    1. For the rimmed steel having ultimate tensile strength of about 35 kg/mm2, of which A3-transfo-rmation-point is 871°C and A1-point 729°C, critical cooling times from A3-point to 500°C are determined as follows; Cz'=0.17 sec, Cf' =0.27 sec, C p'=2.0 sec, Ce'=23 sec. The cooling time corresponding to 50% martensite is 0.47 sec and Ms-temperature 435°C.
    2. For the semi-killed steel having ultimate tensile strength of about 42 kg/mm2, of which A3-point is 842°C and Al-point 719°C, critical cooling times are determined as follows; Cz'=0.26 sec, Cf=0.40 sec, Cp'=2.0 sec, Ce'=55 sec. The cooling time corresponding to 50% martensite is 0.88 sec and Ms-tem-perature 420°C.
    3. For the killed steel having ultimate tensile strength of about 49 kg/mm2, of which A3 point is 832°C and A1-point 718°C, critical cooling times are determined as follows; Cz'=0.68 sec, Cf' =1.04 sec, Cp' =10.0 sec, Ce'=140 sec. The cooling time corresponding to 50% martensite is 1.5 sec and Ms-tempera-ture 415°C.
    4. Each critical cooling times and the cooling time corresponding to 50% martensite tend to become large generally with increase of carbon, manganese and silicon contents of a steel.
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  • H. Sekiguchi, M. Inagaki
    1959 Volume 28 Issue 8 Pages 525-530
    Published: August 25, 1959
    Released: June 12, 2009
    JOURNALS FREE ACCESS
    The authors reported already on the continuous cooling transformation dragrams of steels "Wel-ten 55". In this report, they constructed two continuous cooling transformation diagrams in case of maximum heating temperature 1350°C for the high tensile steels "Wel-ten 50", which are the same type as the steel "Wel-ten 55" but different in ultimate tensile strength. The following results were obtained:
    1. For the steel YD having ultimate tensile strength of about 51 kg/mm2, of which A3-transformation-point is 821°C and A1-point 704°C, critical cooling times from A3 point to 500°C are determined as follows; Cz'=1.4 sec, Cf'=2.3 sec, Cp'=9.2 sec, Ce'=320 sec. The 50% martensite cooling time is 3.6 sec.
    2. For the steel YE having ultimate tensile strength of about 54 kg/mm2, of which A3-point is 819°C and Al-point 702°C, critical cooling times are determined as followed; Cz'=2.0 sec, Cf' =3.7 sec, Cp'=21 sec Ce'=370 sec. The 50% martensite cooling time is 5.3 sec.
    3. For both steels YD and YE, the finishing tempratures of martensite transformation MF could be observed fairly clearly. For the steel YD, the starting temperature of martensite transformation Ms is 405°C and its finishing temperature MF 225°C. For the steel YE, M5-temperature is 400°C and MF 220°C. 4. The each critical cooling times and 50% martensite cooling time of steel YE, of which carbon and manganese contents are higher, are larger than those of steel YD respectively. That is, in cases of the same trade mark "Wel-ten 50", it is recognized that each critical cooling times and 50% martensile cool-ing times of steels change with chemical composition, consiting of carbon, manganese and other contents.
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  • K. Kato, K. Nakai
    1959 Volume 28 Issue 8 Pages 531-536
    Published: August 25, 1959
    Released: June 12, 2009
    JOURNALS FREE ACCESS
    Non-metallic inclusions in mild steel weld metals were analysed by alcohlic iodine method and observed by optical microscope. It was found that larger inclusion particles were sphere or angular (crystal) in shapes and MnO-SiO2 in chmical compositions. Auther considered the mechanism of formation of inclusion particles in weld metal and explained relation between these shapes and chemical compositions.
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  • F. Oshiba, K. Shimizu
    1959 Volume 28 Issue 8 Pages 537-541
    Published: August 25, 1959
    Released: June 12, 2009
    JOURNALS FREE ACCESS
    In the metallic arc welding with a. c. the effect of the inclination of electeode to the steel plate on the arc phenomena was studied and the following results were obtained.
    (1) The max. length of the electric arc which exists between the tip of electrode and the steel plate depends on the angle of inclination of electrode to the steel plate and is given by the next equation,
    L (θ)=(A+B sinθ+C sin 2θ) L(π/2) …………………………………………………………(1) where a is the angle of inclination of electrode to the plate, L(θ) the value of the max. arc length for θ, L(π/2) ditto for the inclination of 90° and A, B and C are conitants.
    (2) The equation for the max. length of the electric arc obtained by the theoretical considerations is quite similar to the experimental one given above.
    (3) The vertical distance of the tip of electrode from the steel plate just when the electric arc attains its max. length depends on the angle of inclination of the electrode as given by the following equation.
    H(θ)={a+b sin (θ-45°)+c sin2 (θ-45°)}L(π/2) …………………………………………………(2)
    where H (θ) is the vertical distance of the tip of electrode from the steel plate, L(1/2) the max. arc length when the electrode inclination is 90° and a, b and c are constants.
    (4) The kind of electrode has definite effect on the max. arc length, namely the max. arc length differs in its magnitude, according to the kind of electrode, in the same order for all inclination angles of electrode.
    The case is quite the same as to the vertical distance of the tip of electrode form the steel plate.
    (5) The arc angle i.e. the angle of arc against the steel plate at its starting point on the plate is always greater than the inclination angle of electrode excepting for 90 inclination, the difference of these angles becoming greater as the inclination of electrode decreases.
    (6) The arc angle decreases as the inclination of electrode decreases to a min. value of about 40° at 22.5° inclination of electrode, but it increases slightly and takes 45° when the inclination angle of electrode becomes 0°.
    (7) The change in the electric current and voltage and also the burn-off rate of electrode were mea-sured in relation to the change of the angle of inclination of electrode.
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  • F. Oshiba, K. Shimizu
    1959 Volume 28 Issue 8 Pages 542-546
    Published: August 25, 1959
    Released: July 14, 2010
    JOURNALS FREE ACCESS
    Using the same method as described in the previours paper, the effect of the size of interval between core wires of electrodes, which are set parallel to each other, on the welding characteristics of the automatic arc welding was studied, and the following results were obtained. (1) The rate of melting of electrode decreases as the interval increases at a given intensity of electric current, and increases as the intensity of electric current increases at a given size of interval. The relation among the rate of melting of electrode, the size of interval between core wires and the intensity of electric current is given by the following formula.
    V= (a-bG)I
    whereV is the rate of melting of electrode, G the size of interval between core wires and Ithe intensity of electric current, and a and b are constants.
    The actual rate of melting of electrode in the case where the core wires contact to each other is less than the calculated value with the above formula putting G=0
    (2) The max. interval across which the arc can move alternately from the one of electrodes to the other at their tips during the course of welding increases as the intensity of electric current increases. It decreases, however, as the diameter of electrode increases.
    (3) The breadth of bead increases first proportionally with the size of interval within a certain limit and thereafter it increases rapidly as the size of interval increases.
    (4) The height of bead decreases first proportionally with the size of interval and then it decreases rapidly.
    (5) The depth of penetration becomes less gradually as the size of interval increases for a certain range while thereafter it decreases rapidly.
    (6) The rate of deposition of molten electrode metal is greater than 80% for the proportionality range described in.(3) and (4).
    (7) The appearance of the bead is almost good if the interval of core wires is kept less than a certain size which is approximately equal to the core wire diameter.
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