JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 52, Issue 1
Displaying 1-9 of 9 articles from this issue
  • Fundamentals of Fracture Mechanics
    Hiroyuki Okamura
    1983 Volume 52 Issue 1 Pages 7-18
    Published: January 05, 1983
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Investigation on Fracture Surface after Fracture Toughness Test
    Shizuo Mukae, Mitsuaki Katoh, Kazumasa Nishio, Siangshuy Chui
    1983 Volume 52 Issue 1 Pages 19-24
    Published: January 05, 1983
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Fracture toughness test was performed on the specimens of SS41 steels including different amount of Ti, which were heat treated using a synthetic thermal cycle apparatus. The streched zone widths on the fracture. surfaces measured using SEM were in proportion to J, values. Plastic strain in the region of the streched zone obtained using X-ray micro-diffractometer was the largest of all the strains obtained. The maximum plastic strains thus obtained increased in proportion to Jc values. Consequently, it would be concluded from this result that the plastic strain in the region of the streched zone obtained by X-ray corresponds to the true fracture strain arising at crack tip.
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  • High Speed Welding of Thin Aluminum Alloy Plate with Twin Electrode Switching TIG
    Satoshi Kokura, Masayasu Nihei, Eiji Ashida, Fumio Taguchi, Itsuhiko S ...
    1983 Volume 52 Issue 1 Pages 25-29
    Published: January 05, 1983
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    A newly developed twin electrode switching TIG welding method, has been applied to the welding of thin aluminum alloy plate. The new method has a characteristic of prevening the arc interaction by alternately switching the welding current to the each electrodes.
    In the welding of 4 mm thick aluminum alloy plate (A5052), the critical welding speed of the new method is about 2 m/min and is about two times as fast as that of a conventional one electrode DCSP TIG welding method. Furthermore, the new method can expand the suitable ranges of the arc voltage and the welding current.
    The resaon for the expanding of welding conditions is due to the reduction of the arc pressure that is about one-forth as low as the conventional one electrode method.
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  • Effects of Shielding Gas Compositions on Properties of Weld Metals
    Seiichi Ando, Michinori Ohkubo, Keiji Gotou
    1983 Volume 52 Issue 1 Pages 29-37
    Published: January 05, 1983
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Hot cracking susceptibility of weld metals by angle expanding type cracking test (gas mixture ratio; 0, 20, 40%), chemical compositions of weld metals by bead welding (0, 10, 20, 30, 40, 50%) and mechanical properties, chemical compositions of weld metals by narrow gap butt welding (gap; 10 mm, 0, 20%) in the flat position and vertical position have been investigated for CO2-O2, Ar-CO2, Ar-O2 gas shielded arc welding of high carbon steel (0.65%C, 0.O26%S). The results obtained are as follows:
    (1) Appropriate shielding gas composition concerning hot cracking susceptibility is CO2+20%O2. In case of Ar-CO2, Ar-O2 shielding gases, hot cracking susceptibility increase as increasing gas mixture ratio.
    (2) In case of bead welding, carbon contents of weld metals increase 0.24%, to 0.34% as increasing gas mixture ratio. Contents of Si, Mn, Ti decrease as increasing gas mixture ratio. Decreasing tendency of these elements are in order of Ar-O2, CO2-O2 and Ar-CO2. Hot cracking are not recognized in the weld .metals:
    (3) In case of narrow gap welding, weld metals with sound mechanical properties (tensile test, impact test) are obtained by CO2+20%O2. Carbon contents of weld metals for butt welding in the flat position are about 0.14-0.15% and for vertical welding are about 0.18% and hot cracking are not recognized in the weld metals.
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  • Takashi Zaizen, Shiro Aoki, Katsumi Suzuki, Seishiro Bando
    1983 Volume 52 Issue 1 Pages 37-45
    Published: January 05, 1983
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Changes of the metallurgical and mechanical properties, in the root pass weld metals accompanied with the repeated welding heat cycles of the multi-layer submerged arc welding, are studied. The obtained results are as follows.
    1) The first and the second time welding heat cycle do not increase the hardness for the root pass weld-metal, and the hardnesses increase from Hv150 to Hv190 between the third and the sixth time welding heat cycle.
    2) Cooling rates down to 500°C for the first time and the second welding heat cycle are 24°C/s and 5.9°C/s, cooling rate decreases till 1.5°C/s for the sixth welding heat cycle.
    3) Precipitates are formed in the S ferrite along d ferrite-austenite boundaries, and the precipitates grow up to about 1000th in size.
    4) Fine precipitates, which diameter are hundreds A, are formed in the austenite matrix, and the disloca-tions in the austenite matrix are fixed by these fine precipitates.
    5) Dislocation densities in the austemte matrix are increased from 108/cm2 to 2×109/cm2 by the released strain accompanied with the six times repeated welding heat cycles.
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  • Study on Penetration Control of Weld (Report II)
    Yuzo Kozono, Satoshi Kokura, Ryoichi Kajiwara, Akira Onuma
    1983 Volume 52 Issue 1 Pages 45-49
    Published: January 05, 1983
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Surface temperature near the, rear end part of moicen pool in a low freqoncy pulsed TIG arc welding for thin thick stainless steel plates was measured with a PbS infrared radiation pyrometer.The dis-turbances of TIG arc on the temperature measurement at the-position about 5 mm away from the center of the arc was preventable at the time of the base current in the low frequency pulsed TIG welding. It was concluded from the temperature measurement that the mutual rleation existed between the surface temperature near the rear end part of the molten pool and thereverse side bead width.
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  • Shigetomo Matsui, Toshio Terasaki, Masaru Sakaguchi, Otomaro Takagi
    1983 Volume 52 Issue 1 Pages 49-55
    Published: January 05, 1983
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The effect of welding conditions on the reaction stress which produced in one pass welded steel was studied by the rigid restraint cracking test machine. Experiments of reaction stress were made by changing the value of each factor of welding conditions such as groove size, heat input, weld length and welding process. The reaction stress was not influenced by heat input when values of other factors were not changed. Equations for estimation of the reaction stress were derived from restraint intensity, mechanical properties of steel and welding conditions.
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  • Penetration Behavior of Liquid Metals
    Hirotaka Ogawa, Akira Ohmori, Tohru Yoshida, Ikuo Okamoto, Yoshiaki Ar ...
    1983 Volume 52 Issue 1 Pages 56-61
    Published: January 05, 1983
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The effect of penetration of liquid metal on the flow stress and fracture properties in LME of carbon steels by Cd-5Zn, Cd-50Zn and pure Cd.was studied. Using smooth and notched specimens, experiments were conducted just above the melting points of the embrittlers, at 350°C, and crosshead rate in a tensile test was 5 mm/min.
    It is shown that apart from the reduction in ductility, the stress-strain curves are slightly altered due to the grain boundary penetration of liquid metals. The results of tensile test with notched specimen also indicate that for the occurrence of LME, the stress or load has to exceed a critical value. Moreover, the mean penetration length of liquid metal at fracture could be estimated, assuming that the fracture stress of steel with liquid metal equals to the ultimate stress (i.e. actual stress) without liquid metal. The data suggest that LME can be evaluated by the mean penetration length.
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  • Hideki Tamura, Mitsuru Aoki, Masato Kobayashi
    1983 Volume 52 Issue 1 Pages 61-66
    Published: January 05, 1983
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    When fillet welded joints with lack of penetration is subjected to bending, the compressive part of incomplete penetration will contact and increase the crack opening displacement.
    In this paper, the stress, intensity factor, K, were analyzed with the aid of finite element method for the case where partial contact occurs, and fatigue tests under pulsating bending were carried out on fillet welded joints with lack of penetration. As a result, the fatigue limit at the root of fillet welded joint under pulsating bending can be evaluated by the application of fracture mechanics technology.
    Moreover, it is found that the partial crack contact result in the slight increase in K-values.
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