JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 42, Issue 1
Displaying 1-7 of 7 articles from this issue
  • Eijiro Sugihara, Katsuyuki Amanuma
    1973 Volume 42 Issue 1 Pages 9-17
    Published: January 25, 1973
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Newly developed voltage reducing devices are described for engine driven AC arc welders of both self and separate excitations.
    Output voltage of the welder is regulated by changing the field current electronically with semiconductor elements.
    Difficulty of rapid arc starting due to large field inductance is eliminated by using a condenser discharge circuit connected to the field winding. Thus, field current can rise very fast to shorten the arc starting time, that is, the buildup time of output voltage of welder. This buildup time is as small as 0.06 seconds which satisfies the Japanese Industrial Standard of voltage reducing device for transformer type AC arc welder.
    Efforts are also made to protect the devices from the damage caused by the vibration of engine. As a result, high reliability and good performance are obtained.
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  • Atsushi Hasui, Junichi Kinugawa, Yasuo Suga
    1973 Volume 42 Issue 1 Pages 18-28
    Published: January 25, 1973
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    A new underwater plasma welding process has been developed. In this process, viscous liquid is used in place of shielding gas to protect the part being welded from the surrounding water and to stabilize plasma arc.
    Welding experiments are done by using steel for welded structure of 6 mm in thickness and it is ascertained that this process can be put to practical use.
    Main results are summarized as follows:
    (1) Water glass is used as a typical viscous liquid.
    (2) Water glass shielding for the part being welded has a marked effect on stabilization of underwater plasma arc.
    (3) Water glass shielding has an effect on heat insulating of the part being welded and lowers the solidification rate of molten metal. Owing to this feature, the weld metal does not include a blowhole and the maximum hardness of the heat-affected zone adjacent to the bond is lowered considerably.
    (4) The weld resulting from this process has excellent mechanical properties, and especially its ductility and notch toughness can be improved remarkably, compared with those of the weld resulting from nonshielding.
    (5) Coefficient of viscosity and flow (feeding) rate of shielding water glass should be selected properly. However, the proper range of combinations of viscosity and flow rate may be relatively wide.
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  • Michio Inagaki, Jun Nishikawa, Rokuro Kohno
    1973 Volume 42 Issue 1 Pages 29-39
    Published: January 25, 1973
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    A newly developed high strength steel HY130(NSC), to which copper has been richly added, is investigated for practical usage. The influence of addition of a large amount of copper on weldability had been so little known that this investigation was carried out to make claer this influence. A hot cracking susceptibility was mainly investigated using the Varestraint Test. HY130(T) and NS63 were also tested to compare with the result of HY130(NSC). Scanning electron micrographs of hot cracks were taken. Distributions of some components were studied with an electron probe microanalyser.
    The results are as follows:
    (1) Hot cracks occur only in bead nearly perpendicular to a ripple line.
    (2) A difference between hot cracking susceptibility of HY130(NSC) and that of HY130(T) is hardly found.
    (3) Scanning electron micrographs of hot cracks show that growth of dendreits relates to hot cracks.
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  • On the Molding Properties
    Hiroshi Kimura, Takuji Yamaguchi, Masakazu Tsubokawa
    1973 Volume 42 Issue 1 Pages 40-47
    Published: January 25, 1973
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    In the present paper, we try to study the molding property and the weldability of fiber glass reinforced polyethylene. Fiber glass reinforced polyethylene is a composite material of the reinforced engineering plastics and the polymer is its main matrix. It presents a difficult property of matter because glass fiber is mixed as the reinforcing agent with polymer (that has the organic physical property), which has makes fiber glass reinforced polyethylene a more complex structure. Therefore its coalescence (for example, molding or welding) becomes one of the difficult and serious problems. However the reinforcing of engineering plastics is one of the important problems to be solved in the future study of engineering materials of plastics and, above all, its bonding is a problem one should not ignore. In this paper we describe an experimental study of its molding property. Fiber glass reinforced thermoplastics used for experimental study had a low density polyethylene as the matrix, random mat of glass fiber as reinforcing agent.
    The following summary can be made from the results of the present experiment. Fiber glass reinforced ployethylene could acquire'satisfactory properties by the proper treatment before molding.
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  • Investigation for Commercially Used Aluminum and Aluminum Alloys
    Tomio Senda, Fukuhisa Matsuda, Genta Takano
    1973 Volume 42 Issue 1 Pages 48-56
    Published: January 25, 1973
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    In fusion welding of structural aluminum alloy plates solidification cracking frequently occurs in the weld metal and gives rise to serious problems for the soundness of the welded joint.
    In this report, using the Trans-Varestraint test which was developed previously, authors have investigated the sloidification crack susceptivility of commercially used structural aluminum alloy plates.
    Firstly the time required for straining in the specimens given by various bending blocks and the time required for the propagation of solidification crack during straining were dynamically investigated. using 6.1mm thick 5083 aluminum alloy plates. Secondly the properties of the ductility whithin the solidification brittleness range were measured and also evaluated for eleven commercial aluminum alloys.
    The main conclusions obtained are as follows:
    (1) In the observation with high speed cine camera the propagation of the solidification crack which occurs during the Trans-Varestraint test was so fast that the time required for the completion of a crack was from 0.005 to 0.02 sec in the case of 2.1% augmented-strain for a 6.1mm thick 5083 aluminum alloy plate.
    Moreover a crack started in the vicinity of the trailing end of the puddle and propagated rearward of the puddle along the weld bead.
    (2) Indices of crack susceptibility such as the brittleness temperature range (BTR), the minimum augmented-strain required to cause cracking (emin) and the critical strain rate for temperature drop (CST) were decided for these aluminum alloys. Thus, in order of the CST value these alloys are placed in this experiment as 1070. 3003, (7075, 5154, 5052, 2024), (6061, 2017, 74S, 5052) and 5083.
    (3) The BTR for each alloy is roughly proportional to the nominal solidification temperature range between liquidus and solidus, although there is a considerable scatter. Moreover the CST value for each alloy can be approximately represented by the εmin/BTR.
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  • Kunihiko Satoh, Yukio Ueda, Hiroshi Kihara
    1973 Volume 42 Issue 1 Pages 57-72
    Published: January 25, 1973
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Download PDF (922K)
  • 1973 Volume 42 Issue 1 Pages Plate1-Plate4
    Published: January 25, 1973
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Download PDF (5886K)
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