JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 46, Issue 5
Displaying 1-7 of 7 articles from this issue
  • Yasuhiro Iwasaki
    1977 Volume 46 Issue 5 Pages 237-243
    Published: May 05, 1977
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Kohsuke Horikawa
    1977 Volume 46 Issue 5 Pages 244-251
    Published: May 05, 1977
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Yukio Arita
    1977 Volume 46 Issue 5 Pages 252-257
    Published: May 05, 1977
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Atsushi Hasui, Masayuki Ogawa, Kenji Okada
    1977 Volume 46 Issue 5 Pages 258-264
    Published: May 05, 1977
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The possibility of friction welding of malleable cast iron and S48C carbon steel of 12 mm diameter was investigated. And experiments on some fundamental welding phenomena to be related with the tensile property of the joint were carried out.
    The welding machine used was of continuous drive type, and the experimental range of the weld-ing factors was,
    rotational speed: 3600 rpm,
    heating pressure: 4.0-9.0 kg/mm2,
    upsetting pressure: 9.0 kg/mm2,
    heating time: 20-80 sec.
    Main results of the study are as follows;
    (1) When heating pressure Ph of 6.0, 7.0 and 8.0 kg/mm2 and the comparatively long heating time are selected, the joint having the tensile strength equivalent to that of base metal can be got. The specimen obtained under the condition of heating pressure 7.0 kg/mm2 and heating time 40 sec trends to be broken at base metal in tensile test.
    (2) To get such sound joint that fracture takes place at base metal in tensile test, it is required that the graphite adjacent to friction interface in cast iron is diffused in its surrounding ferrite and the region enriched with carbon by diffusion is molten so far as the graphite disappears. Moreover, the requirement that graphite in the area continued to the above-mentioned area should not be flattened severely is added.
    (3) In the joint broken at the weld, the graphite adjacent to the interface remains in severely flattened state or finely torn.
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  • Cutting Phenomena
    Masanobu Hamasaki, Fumikazu Tateiwa, Munehide Katumura, Yoji Ogawa
    1977 Volume 46 Issue 5 Pages 264-270
    Published: May 05, 1977
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The authors are developing a consumable electrode water jet technique as an underwater cutting method, which has such characteristics as low cost, high working efficiency, possibility of cutting various metal and high degree of safety. With this cutting technique, it was also found out interesting facts that cutting for thick plate could be done at arc voltage of 40V, and change of cutting current depended on the cutting speed and had little to do with the wire feeding rate. Therefore as the result of observing arc phenomena whilst cutting proceed using high speed motion camera and oscillograph, the following conclusion was introduced.
    An arc is struck between an electrode and the work, a jetting water is directed at the cut portion to blow away the molton metal, and the arc is therefore moved from anupper side to a bottom side, where the arc is extenguished, but the arc re-ignited by the contacting of the wire and the work. By repeating this phenomena, arc cutting proceed smoothly.
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  • Austenite Grain Growth during Thermal Cycle in Steels
    Hiroshi Ikawa, Shigeo Shin, Hiroaki Oshige, Yutaka Mekuchi
    1977 Volume 46 Issue 5 Pages 270-278
    Published: May 05, 1977
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    In this report, grain growth equation during thermal cycle, derived by the authors, was applied to the austenite grain growth of steels during thermal cycle.
    At first, the formation of austenite grains during rapid heating was examined, and then the method to calculate austenite grain growth during thermal cycle was investigated using grain growth equation during thermal cycle.
    Main results obtained are as follows.
    1) When 0.2 and 0.35 % carbon steels (initial microstructure: ferrite-pearlite, ferrite grain size:0.01-0.04mm) heated rapidly, austenite grains are formed at 950-1050°C and grain size of the austenite formed is 0.013-0.02 mm.
    2)When low alloy steels (initial microstructure:martensite, tempered martensite, prior austenite grain size: 0.020.38mm) are heated rapidly, austenite grains are formed at 950-1050°C and grain size of the austenite formed is 0.01-0.05 mm.
    3)It was confirmed that austenite grain growth could be calculated by grain growth equation during thermal cycle using the results mentioned above as initial conditions.
    4)In case of the normalizing or quenching and tempering conditions for practical use, austenite grain growth during thermal cycle above 1000°C can be calculated assuming that austenite grain size is zero at the finishing temperature of austenite transformation.
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  • Dissolution Phenomenon of Carbides During Isothermal Heat Treatment
    Hiroshi Ikawa, Shigeo Shin, Yoshikuni Nakao, Kazutoshi Nishimoto, Taka ...
    1977 Volume 46 Issue 5 Pages 279-285
    Published: May 05, 1977
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The dissolution phenomena of MC type carbides in HAZ of SUS 321 and SUS 347, which were the commencements of knife line attack phenomena in these steels, were quantitatively and theoretically considered.
    In this report, as the first step to make clear these phenomena, the dissolution phenomenon of Nb(C, N) in SUS 347 under isothermal heat treatment was analyzed theoretically on the basis of diffusion controlled model of Nb.
    In order to obtain (∂C/∂r)r=R in a theoretical equation, the sperical approximation which was reported by Zener, was adopted.
    By comparing theoretical values with experimental results, the validity of this model was discussed. The results obtained in this report are as follows;
    (1)Two different theoretical equations were derived. One is derived on the assumption of the radius of Nb(C, N) being uniform, and the other is derived by considering the distribution of radius of Nb(C, N)
    (2)Comparing theretical values with experimental results, the validity of the theoretical equation derived by considering the distribution of radius of Nb(C, N) was proved.
    (3)The fact that the obtained n value in Johnson-Mehl's equation is about 3/2 concerning the dissolution phenomenon of Nb(C, N) in SUS 347 supports diffusion controlled reaction model proposed in this report.
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