JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 36, Issue 6
Displaying 1-10 of 10 articles from this issue
  • Michio Inagaki, Harumasa Nakamura
    1967 Volume 36 Issue 6 Pages 597-607
    Published: June 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Kazumi Mori
    1967 Volume 36 Issue 6 Pages 608-619
    Published: June 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Fatigue Properties of Notched Specimens of Mild Steel, 60kg/mm2 High Strength Steel and their Welded Parts
    Masaki Watanabe, Kinichi Nagai, Tsuneaki Yamaguchi, Shin Hioki
    1967 Volume 36 Issue 6 Pages 620-627
    Published: June 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The purpose of this study is to find the reason for decreasing fatigue strength (N=2×106) of welded joint of structural steels, especially of high strength steels of which fatigue strength (N=2×106) is only a little greater than that mild steel, in spite of the excellence in other mechanical properties.
    It is considered that there are the following factors which reduce the fatigue strength (N=2×106); (1) notch sensitivity of stress concentration due to reinforcement and welded defects, (2) metallurgical discontinuity and (3) the resistance to crack propagation in case of notched specimens like welded joint.
    In order to clarify how these factors affect the fatigue strength of high strength welded joint, fatigue test was made using the specimens notched at base metal, heat affected zone, bonded part and deposit metal of mild steel (SS41) and 60 kg/mm2 high strength steel (HT60) with various stress concentration factors α (α=1.00, 1.16, 1.57, 1.93, 2.56, 3.90).
    In case of sharp notched specimen, non-propagating crack is found at notch root, even though it might be stressed under fatigue limit, and it is possible to distinguish two fatigue limits: one is the stress to limit initiation of crack and the other is the stress to limit propagation of non-propagating crack. Therefore, notch sensitivity for crack initiation and propagation can be discussed of two steels and their welded parts, by comparing these fatigue limits with those of plain specimens.
    From these test results, the following charactaristics were known:
    I) Notch Sensitivity for Crack Initiation.
    1) Base Metal: SS41<HT60
    2) Heat Affected Zone: SS41<HT60 (α is small), SS41-HT60 (α is large).
    3) Bonded Part: SS41<HT60 (α<2.3), SS41<HT60 (α<2.3)
    4) Deposit Metal: SS41<HT60 (α is small), SS41-HT60 (α is large).
    II) Notch Sensitivity for Crack Propagation.
    Base Metal and Welded Parts: SS41<HT60. Fatigue limits for crack propagation are 12.0 to 13.5 kg/mm2.
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  • Effects of upsetting time on properties of friction welds
    Atsushi Hasui, Sadao Fukushima
    1967 Volume 36 Issue 6 Pages 628-632
    Published: June 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    It is generally said that the sudden stop of spindle and the instantaneous upsetting are both the important processes in the final phase of friction welding. However, there is no paper on upsetting time.
    Thereupon, welding was carried out to investigate the effects of upsetting time on strength of friction welded joint. In this experiment, 0.45 and 0.25 per cent carbon steel rods were used as specimens. The welding conditions were kept constant, except that the upsetting time relating to stop time of spindle was varied. Effects of upsetting time on properties of joints were judged by roller bend test.
    The results are as follows;
    (1) In order to get a satisfactorily welded joint, it is desirable to so adjust as to start the upsetting process just before the spindle is stopped.
    (2) Even under improper welding condition in previous experiments, in which upsetting time was not so controlled, a satisfactorily welded joint was obtained by adjusting the upsetting time to the abovementioned state.
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  • Tsuguyasu Wada, Makoto Tanabe
    1967 Volume 36 Issue 6 Pages 633-636
    Published: June 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    A method for testing shear strength of brazed joint has been proposed. The method is based on a compress shear test of a lap joint with two plates of 3 mm thick. The strength obtained by this method may be compared with that by AWS method for shear test. For stainless steel joint brazed with a silver brazing alloy, BAg-I, the agreement was fairly good between strengths obtained by this method and by AWS method. For mild steel joint, which showed considerable dependence of strength on the overlap distance, a slight difference was observed between results by those two methods.
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  • Yugoro Ishii, Tadao Onzawa, Masaaki Hirose
    1967 Volume 36 Issue 6 Pages 637-642
    Published: June 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    As a basic study of brazing, two dissimilar metals in contact with each other were heated to a specified temperature and fused in an electric furnace, then the micrographic structure of the bonded layer was studied to establish the relation between the microstructure of the layer and the heating temperature.
    As the simplest case, this paper is concerned with the microstructure of the combination of pure metals which form eutectics. The microstructure of bonded layer was determined by X-ray microanalyser and X-ray diffractometer.
    Six combinations (Bi-Cd, Bi-Sn, Ti-Cu, Ti-Co, Ti-Ni and Zr-Ni) were treated as the specimen, each combination being examined individually. The following results were obtained:
    i) The temperature for producing the molten layer must be, at least, over the lowest (or the first) eutectic temperature on the equilibrium diagram, and the composition of the molten layer agrees with that of eutectic point (see photo. 1, 4, 8, 13).
    ii) When the temperature rises further and attains the upper (or second) eutectic point for instance a eutectic temperature, 1135°C, 82 wt% Co system such as the case of Ti-CO system, in the case of Ti-Cu and Zr-Ni, the second eutectic structure co-exists with the first eutectic structure depending on the speed of its producing process (see photo. 6, 14). However, in the case of Ti-Co and Ti-Ni, the whole specimen melts by heat which is produced by metallic compound formation constituting its eutectic structure (see photo. 9, 11).
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  • Mitimasa Kono, Takasi Ueki
    1967 Volume 36 Issue 6 Pages 643-648
    Published: June 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    We tested the quality of electroslag welds in which the 600 mm dia hull steel casting was joined with hull steel forging.
    Electrode and flux used in the test were Kobe Steel US-40 electrode (3.2 mm dia) and G-90 flux.
    Welds were very sound. No defects were found on weld metals, fusion line, and heat-affected zone.
    The static strength on the welds was never inferior to that of base metal.
    The rotary bending fatigue strength of fusion line was 19.9 kg/mm2 on the side of forged steel and 18.3 kg/mm2 on the side of cast steel, tensile strength ratio being 39.8% on forged steel side and 36.2% on cast steel side.
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  • Investigation of Induction Period by Method of Preimmersion
    Masaki Watanabe, Yoshihiko Mukai, Yoshinobu Oka, Hajime Nakasugi
    1967 Volume 36 Issue 6 Pages 649-656
    Published: June 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    We investigated the mechanism of stress corrosion cracking during the so called "induction period" before cracks initiated, by using the method of preimmersion.
    During the induction period, the corrosion potential of test piece rose more and more independently of the load value, until at last it reached the necessary value causing the occurrence of "micro-pitting" which was believed to be the initial stage of stress corrosion cracking. If the necessary value of stress was applied at that time, cracks immediately started.
    Then it may be said that the stress is not necessary untill the potential of specimen reaches the necessary value described above.
    The material was not found to be attacked by corrosion agent, and become brittle during the induction period.
    Moreover, we obtained the values of the threshold stress for crack initiation and that for crack propagation, and generally speaking the latter had a lower value than the former.
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  • Age and Work Hardening
    Jitsuhiko Ueda, Setsuji Minehisa, Hizô Gô, Kô Nishim ...
    1967 Volume 36 Issue 6 Pages 657-661
    Published: June 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    An attempt has been made to improve the strength of the welded part of an AI-Zn-Mg alloy by mechanical working. Age hardening and work hardening behavior of the alloy were investigated by hardness and tensile tests, and microscopic observations. The experimental results obtained are summarized as follows.
    (1) Typical age hardening was observed in ageing below 100°C and hardening in the early stage of ageing below 80°C was found to be great.
    (2) Work hardening by rolling was found to occur both before and after ageing. There was a big difference in work hardening behavior between the two. The maximum hardness reached by working after ageing was higher than before ageing.
    (3) There was a linear relation between hardness and tensile strength.
    (4) Cold rolling before ageing has a little effect on the age hardening.
    (5) Recrystallization temperature of the alloy was found to be about 250°C.
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  • Atsushi Hasui, Shigeru Kitahara, Takeshi Fukushima
    1967 Volume 36 Issue 6 Pages 662-668
    Published: June 25, 1967
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    In order to compare with characteristics of the plasma jet described in the previous report, some properties of the oxy-acetylene flame for spraying which is now utilized extensively, that is, the gas velocity, the temperature distribution, the composition of gas and the mixing rate of air into the flame and the flying velocity of spraying particles (Mo, Al2O3 and ZrO2) along the flame axis at the various distances from the nozzle under the ordinary operating conditions, are experimented.
    For instance, at the 100'mm distance from the nozzle, the summary of results is the following.
    (1) Flying velocity of spraying particle
    Powder process Al2O3:55 m/sec, ZrO2: 40-45 m/sec
    Wire process Mo: 60 m/sec
    (2) Gas velocity
    Powder process 50 m/sec, Wire process 160 m/sec
    (3) Temperature
    Powder process 1, 900°C, Wire process 500°C
    (4) Mixing rate of air into flame
    Powder process 60%, Wire process 85%
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