JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 41, Issue 1
Displaying 1-10 of 10 articles from this issue
  • Atsushi Hasui
    1972 Volume 41 Issue 1 Pages 8-18
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Tatsuya Hashimoto, Kinji Tanuma
    1972 Volume 41 Issue 1 Pages 19-27
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Fujio Tomiyasu
    1972 Volume 41 Issue 1 Pages 28-33
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Proposal on Determination of actual preheating condition
    Kunihiko Satoh, Shigetomo Matsui, Yoshinori Ito, Kiyoshi Bessyo
    1972 Volume 41 Issue 1 Pages 34-46
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Control of weld cracking is one of the most important problems on welding steel constructions.
    In this present report, practical use of weldment cracking parameter Pw previously proposed is undertaken for avoiding weld cracking in steel constructions. The relation of the Pw-value versus critical cooling time (tc) cr of weld is found to be applicable for weld heat input less than 30, 000 J/cm.
    Preheating conditions to assure no weld cracks are proposed as a function of the Pw-value founded on previous study. And determination of preheating temperature in steel constructions from y-groove weld cracking test results is also proposed. Weld cracking tests of full size model specimen reveal above proposals being applicable successfully.
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  • Further Investigation on Precipitations and Structures of Weld Heat-Affected Zone
    Hiroshi Ikawa, Shigeo Shin, Mitsuaki Yoshikawa
    1972 Volume 41 Issue 1 Pages 47-58
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    In the weld heat-affected zone of 17-4 PH stainless steel, the softened region is formed. And the authors supposed in the previous report that the cause of the formation of this region is overaging and retained austenite.
    Therefore, in the present study, the weld heat-affected zone of 17-4 PH was examined directly by transmission electron microscopy at first. Next, the behaviors of precipitation and reverse transformation were examined. And lastly the mechanism of formation of retained austenite in this material was confirmed.
    Main results obtained are as follows.
    (1) In the softened region of weld heat-affected zone, overaging was confirmed by transmission electron microscopy.
    (2) The main constituting element of precipitate of 17-4 PH is copper and nickel has not remarkable effect on the formation of precipitate.
    (3) Precipitate is present in delta-ferrite at fairly high temperature in rod-like shape.
    (4) Aged at relatively high temperature, precipitate changes into spherical in reversed austenite. And orientation relationship between this spherical precipitate and matrix martensite satisfies the relationship by Kurdjumov-Sachs.
    (5) Reverse transformation from martensite to austenite of 17-4 PH is controlled by diffusion process.
    (6) Retained austenite in 17-4 PH is caused by nickel-rich austenite formed by decomposition of martensite heated between As and Af.
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  • The Investigation of Stress Relief Cracking Susceptibility on Low Alloy Steels
    Yoshinori Ito, Mutsuo Nakanishi
    1972 Volume 41 Issue 1 Pages 59-64
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The effects of alloying elements on the tendency toward heat-affected-zone cracking due to stress reliefing heat treatment have been investigated with y-groove restraint SR cracking test specimens.
    To investigate the effect of composition, about 50 low alloy steels were obtained with different content of C, Cr, Mo Cu, V, Nb and Ti.
    The following results were obtained from this investigation.
    The stress relief cracking susceptibility of a steel can be described by PsR=[%Cr] +[%Cu] +2[%Mo]+10[%V]+7[%Nb]+5[%Ti]-2
    PsR≥0, cracked if %Cr≤1.5, 0.10≤%C≤0.25
    where PsR is stress relief cracking susceptibility index, and [%Cr], [%Cu], etc. are the content of alloying elements in weight %.
    However, the stress relief cracking susceptibility, of high Cr steels (Cr≥1.5%) and extremely lower C steels are low in spite of high value of PSR. Therefore, the stress relief cracking susceptibility of these steels cannot be represented by the value of PsR.
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  • Effects of Roughnese on Soldered Joint
    Ichiro Kawakatsu, Yoshifumi Suezawa
    1972 Volume 41 Issue 1 Pages 65-74
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Usually, the mechanical properties of soldered joint of mild steel are affected by various factores, for instance, substance of base metal, solder and flux, surface preparations such as finishing and roughness, joint clearance, presence of defects as prosity and unsoldered area or void. Among these factores, surface preparation especially roughness of base metal is very important for the tensill strength of soldered joint of mild steel. This paper presents some experimental evidences that roughness of base metal prepared by following process affects the tensile strength of mild steel (SS41) butt joint soldered by Pb-Sn alloy:
    (1) Polishing by emery paperes (emery No. 60, 120, 240, 400, 600)
    (2) Machining by plain milling cutter.
    (3) Grinding by 604# grinding wheel.
    (4) Grinding by 80# grinding wheel.
    Above process were carried out with one direction on the soldering surface of the base metales. To obtain some experimental data, soldering operation of these specimens was carried out in the 0.3 Kw small electric soldering bath installed the heat-controll (±5°C) unit using ZnCl2-NH4Cl flux. These soldering temperatures were 200°C, 250°C, 300°C, 350°C, and joint clearance was adjusted by using the device of Photo. 3 for very short time. Tensile test of these specimens gave the results as follows:
    (1) Among the these specimens polished by various emery paperes, specimens polished by emery No. 600 gave the highest tensile strength, its value being 20.87 Kg/mm2 (t=0.18 mm). But specimens polished by emery No. 60 gave lower strength, its value being 13.74 Kg/mm2 (t=0.22 mm) at the 250°C soldering temperature.
    (2) These specimens soldered at 250°C gave high tensile strength and specimens soldered at 350°C gave lowest strength, also specimens soldered at other temperature gave lower strength than that of the specimens soldered at 250°C.
    (3) Tensile strength of specimens ground by 80# grinding wheel was very high, its value being 22.05Kg/mm2 (t=0.28 mm), and specimens ground by 60# grinding wheel was lower, its value being18.22 Kg/mm2 (t=0.24 mm). Also, tensile strength of specimens machined by milling cutter showed17.51 Kg/mm2 (t=0.35 mm).
    Also, studies on spreadabilty of Pb-Sn alloy on the base metal with various roughness were conducted at the soldering temperature 250°C and 350°C. To obtain some experimental data, mild steel plates (SS41 500φ × 1.6/) polished by emery paper No. 60, 120, 240, 400, 600, and mild steel disc machined by milling and grind ing process were prepared. Also, Pb (61.9%)-Sn (38.1%) filler metal (wt= 1 g) were prepared. This experiment was carried out using a small resistance soldering bath (0.3 KW). As a result, spreadabilty of filler metal on the specimens polished by large grain size emery paper was better than that of one polished by small grain size emery paper, and there are a few difference between spreadabilty of filler metal on the specimens prepared by milling and grinding process.
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  • The Change of Solidification Structure in Aluminum weld metal
    Tomio Senda, Fukuhisa Matsuda, Mitsuaki Kato, Hiroji Nakagawa
    1972 Volume 41 Issue 1 Pages 75-82
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The changes and the construction mechanism of solidification structure were investigated for the weld metal which had been welded with a moving arc heat source. The materials used were aluminum sheets with different chemical compositions. The conclusions obtained are as follows:
    (1) The nominal growth rate in the weld metal increases generally as the inward growth proceeds, while the temperature gradient decreases.
    (2) When the welding is performed in a condition that the bead width is almost the same, the values of the temperature gradient decrease as the welding speed increases. Accordingly the extent of the constitutional supercooling zone in the weld metal increases as the inward growth proceeds and besides the welding speed increases.
    (3) The columnar crystals develop in the weld metal and under certain circumstances the equiaxed dendrites develop near the center of the weld metal.
    (4) In the 99.96%- and 99.93%-aluminum sheets, the planar growth is observed near the fusion boundary and afterwards the cellular subgrain is observed. In this case the equiaxed dendrites do not develop.
    (5) In the commercially pure aluminum sheets, the solidification structure changes from planar to cellular subgrain and cellular dendrite as the inward growth proceeds. The equiaxed dendrites develop near the center of the weld metal when the welding is performed in a high speed.
    (6) In aluminum alloy sheets, the cellular dendrite is observed even near the fusion boundary and afterwards a lot of equiaxed dendrites develop.
    (7) The changes of the solidification structure shown in (4), (5) and (6) can be accounted for in terms of the phenomenon of the constitutional supercooling.
    (8) When the welding is performed in a condition that the bead width is almost the same, it becomes easy for the equiaxed dendrites to develop in the weld metal as the welding speed increases. This phe-nomenon will be accounted for in terms of the extent of the constitutional supercooling zone.
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  • Zen-ichi Murakami, Minoru Nishida
    1972 Volume 41 Issue 1 Pages 83-92
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The microstructures of the interface of SUS 27, SUS 28 and SUS 29 stainless explosive cladding steel, 5 Cr-0.6 Mo over-lay cladding steel and SUS 27 roll cladding steel which had been subjected to heat treatments at various temperatures were investigated by microscopy and electron probe microanalyzer, and the correlations between width of decarburized band and carburized band, heat treatment temperature and time were examined.
    It was found that the width of decarburized and carburized band could be correlatable by means of the parameter equation of Christoffel-CLirran, P/=-K1T+logt, or the parameter equation of Larson-Miller, P2=T (C+logt). For the aluminium explosive cladding steel, exposure to a high temperature for a long time promotes interdiffusion of aluminium and iron, The width of interdiffusion band may be correlatable by Larson-Miller parameter.
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  • 1972 Volume 41 Issue 1 Pages Plate1-Plate4
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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