JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 36, Issue 7
Displaying 1-9 of 9 articles from this issue
  • Michio Inagaki, Akira Okada
    1967 Volume 36 Issue 7 Pages 694-705
    Published: July 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Kiyoshi Terai, Masayasu Arikawa
    1967 Volume 36 Issue 7 Pages 705-714
    Published: July 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Summarization on the Hydrogen Embrittlement of Cathodically Charged Steel Specimens
    Iwao Onishi, Yoneo Kikuta
    1967 Volume 36 Issue 7 Pages 715-719
    Published: July 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Authors have been investigating on the hydrogen embrittlement and the behavior of hydrogen in steels (absorption, permeation etc.) from a fundamentally new standpoint for these several years.
    Before reporting the new experimental results, we should inform the results summarily that had been obtained and been published by us.
    The experiments had been carried out using 18 kinds of steels and their weldments charged by the cathodically electrolytic method, under 12 kinds of testing conditions.
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  • Stress Relief Test of HT 60 Using H-type Restraint Specimen
    Zinkichi Tanaka, Tadayoshi Obata
    1967 Volume 36 Issue 7 Pages 720-727
    Published: July 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The maximum residual stress in a welded plate has been measured on the weld bead. The weld bead would behave differently from base metal in stress relief heat treatment. In this report, stress relief treatment effect in a composite specimen which consisted of base metal and deposited metal was studied using HT 60.
    A modified H-type specimen in which the weld bead was parallel to tensile residual stress, namely the so-called HL specimen, was proposed. To determine the effect of weld, an HB specimen, in which all parts were composed of base metal and the residual stress was induced by thermal contraction, was also used. Using these specimens, plastic deformation of weld and base metal could be measured by use of Pfender contact strain gauge. Finally, a wide welded plate (500×500 mm) was also used to study stress relief heat treatment effect.
    The results obtained from above three test specimens and relaxation tests were compared mutually and the mechanism of stress relief was discussed. The results are summarized as follows:
    1 The decrease of residual stress in HL specimen due to stress relief treatment was in relatively good agreement with that in wide welded plate.
    2 The reduction of residual stress in HB specimen coincided comparatively well with relaxation test results and deviated from that in wide welded plate only when stress relief temperature was lower than 600°C.
    3 The abrupt reduction of residual stress in HL specimen at lower temperature of stress relief treatment might be due to structural changes of deposited metal and heat affected zone.
    4 The reduction of residual stress in H-type specimen was mainly due to plastic deformation of tension member and some part of plastic deformation of tension member was absorped into elastic strain of restraint members, so stress reduction per unit plastic deformation became smaller in I-I-type specimen than in relaxation test. But when stress relief temperature became higher than 600°C, a plastic deformation took place in restraint members and the residual stress amounted to a certain value specified by base metal properties independently of type of specimens.
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  • Effect of potential change on initiation and propagation of crack by electrolysis
    Masaki Watanabe, Yoshihiko Mukai, Kiyoshi Ueno, Ryoichi Suzawa
    1967 Volume 36 Issue 7 Pages 728-737
    Published: July 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    We discussed the relation between corrosion potential and the so called "induction period" of austenitic stainless steels which.were subjected to stress corrosion cracking test under cathodic or anodic electrolysis.
    In the case of cathodic electrolysis, the corrosion potential of the test piece was lowered. Consequently, it took longer time until the corrosion potential reached the necessary value for initiation of crack described in the previous reports. Therefore, the induction period was also lengthened. .
    When the current density of cathodic electrolysis increased sufficiently, no stress corrosion crack occurred during the test time. In this case, the corrosion potential did not reach the necessary value for initiation of crack.
    This is the mechanism of prevention of stress corrosion cracking by the cathodic electrolysis.
    Next, we applied the cathodic current to the restrained welded plate being under stress corrosion test, and proved that the cathodic electrolysis would be effective to prevent stress corrosion cracking.
    Moreover, we made clear that the propagation of stress corrosion crack could also be controlled by the corrosion potential of test piece.
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  • Series Spot Welding of Various Materials
    Toshio Yamamoto, Takio Okuda
    1967 Volume 36 Issue 7 Pages 738-745
    Published: July 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Shunting current and tensile shear strength in series spot welding of 18-8 stainless steel, aluminium and tinned plate were studied. Especially for shunting current the shunting current equation proposed for mild steel was discussed about above materials. Further, an indicator WC of shunting current has been derived and series spot weldabilities of other various materials are given using WC.
    As the result of experiment and consideration the following were concluded.
    (1) Upper plate shunting current of stainless steel and aluminium are 0.3 and 0.9 times that of mild steel respectively but in aluminium the ratio Il/Iu is large as compared with that of mild steel or stainless steel.
    (2) Shunting current of tinned steel is 0.4 times that of steel, therefore good welding results are obtained in the series spot welding of tinned plate.
    (3) Linear relationship exists between upper plate current of various materials and indicator of shunting current WC=log pO3/pT2 and magnitude of shunting current is expressed by this indicator.
    (4) Using the indicator WS given in equation (6) series spot weldabilities of various materials are obtained.
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  • Effect of Pitch on the Fatigue Strength
    Teruyuki Ueda, Shoichi Yokobori, Takeo Oikawa, Hidetoshi Kawataka
    1967 Volume 36 Issue 7 Pages 746-757
    Published: July 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    To ascertain the effects of the pitch of spots on the fatigue strength, two kinds of spot welded joints with pitches of 10-60 mm were tested under pulsating tensile loads (stress ratio 0). The first was made by lapping and joining two stainless steel plates and was named SUS+SUS. The second was made of a stainless steel plate and a carbon steel plate lapped and joined together, SUS+SPC. In order to explain the relation between the pitch and the fatigue strength of joints, also studied were the effect of the pitch on the welding consequences (nugget size, structure of heat affected zone and welding residual stress) and the relation between the pitch and stress concentration at the nugget edge where the joints failed due to fatigue.
    In the results of fatigue test, the fatigue strength expressed by the load per one.spot, at any life, was not necessarily constant but had a tendency to lower as the pitch became smaller. In SUS+SPC joints, fatigue ratio (fatigue strength/tensile strength) was approximately constant regardless of the pitch. In SUS+SUS joints the ratios for lives up to 106 cycles were also constant, for longer lives over 106 cycles, however, the ratios decreased with an increase of the pitch.
    Effects of the pitch on the consequences of welding were obtained as follows. Concerning the size of nugget and the microstructure of heat affected zone around the nugget, no considerable differences by the pitch were observed. However, concerning residual stress caused by welding which was measured by X-ray diffraction (sin2 Ψ method), the differences due to the pitch were great. For instance, the residual stress at the nugget edge was estimated about 39 kg/mm2 with a pitch of 60 mm, while it was about 24 kg/mm2 with one of 20 mm (for SUS+SUS joints).
    By stress measurement with electric wire strain gauges and stress analysis, relations between the stress concentration at nugget edge and the pitch were obtained. In this result for SUS+SUS joints, the stress concentration with a pitch of 60 mm was about 2.4 times as that for 20 mm pitch.
    Taking the residual stress and the stress concentration at nugget edge into consideration on the fatigue strength at 107 cycles for SUS+SUS joints, for any pitches, the maximum stress of stress cycle at nugget edge was approximately identical to the proof stress of the base material, and so it was pointed out that the effect of the residual stress on fatigue strength was very important.
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  • Impact value of weld metal
    Isao Masumoto, Kaneyuki Imai
    1967 Volume 36 Issue 7 Pages 758-765
    Published: July 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The effect of several elements on impact value of low nickel alloy steel weld metals was investigated by a bead-on-plate experiment, with deposit by the CO2-O2 arc welding using several electrode wires of various compositions. The following results were obtained:
    (1) If a low nickel alloy steel is welded by high current automatic welding with an electrode wire of which composition is the same as base metal, it is difficult to get an as-welded metal, of which the impact value is equal to that of base metal.
    (2) Though it is generally said that nickel has a highly beneficial effect on the low temperature notch toughness of steel, nickel of as-welded metals of low nickel alloy steels did not improve its impact value so effectively as that of heat-treated base metal.
    (3) In as-welded metal molybdenum was more effective than nickel to improve the impact value.
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  • Hajme Nakamura, Yoshikazu Kuriyama, Yasuhisa Yamazaki
    1967 Volume 36 Issue 7 Pages 766-773
    Published: July 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    A new ultra-high-tensile-strength steel was developed by addition of proper amount of AlN, which is known as IN-treatment, to a commerical 80 kg/mm2 high tensile strength steel. The development was carried out as a joint work with the YAWATA IRON & STEEL CO., LTD, Prior to use for steel structure or pressure vesseles, various weldability tests were undertaken, and it has been established that the ultra-high-tensile-strength steel has completely satisfactory weldability. After the tests, authors reached following conclusions.
    1. Weld-joint properties are satisfactory and quite comparable to those of base metal, when optimum welding condition is applied.
    2. To increase the ductility in free bend specimen of weld-joint, it is necessary to keep weld-heat-input to a range of 20, 000-32, 000 joule/cm.
    3. Preheating to 120°C or higher is quite effective to avoud cracks in 25 mm thick weld-joint.
    4. Some deterioration is observed in weld-heat-affected-zone in V-notch charpy impact test for weldment. Authors have pointed out the need for further investigation of the phenomenon.
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