JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 38, Issue 6
Displaying 1-10 of 10 articles from this issue
  • Takeo Naka
    1969 Volume 38 Issue 6 Pages 562-571
    Published: June 25, 1969
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Toshiyasu Fukui
    1969 Volume 38 Issue 6 Pages 572-581
    Published: June 25, 1969
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    A study was made of the eutectic-melting and micro-fissuring in welds of Al-Mg, Al-Mg-Si, Al-Cu, AI-Zn-Mg-Cu and Al-Zn-Mg alloys.
    Experiments were carried out on the effects of various factors on the formation of eutectic-melting and micro-fissuring, and on the sequence of formation of these phenomena and their mechanisms.
    The results obtained were summarized as follows.
    1) Eutectic-melting and micro-fissuring were observed often in the multi-pass welds of aluminum alloys, subjected to the heat-input from the subsequent pass.
    2) The formation of eutectic-melting and micro-fissuring was influenced by welding conditions, thickness of base metal, pass-numbers, inter-layer temperatures, restraint, forced cooling, compositions of base and filler metals and so on.
    The more the heat-input to welds increased, the more the eutectic-melting and micro-fissuring of welds were observed.
    3) Micro-fissuring due to eutectic-melting was generated on the re-solidification of the partially melted zones, where the boundary segregation of eutectic-compositions with low melting temperature was observed.
    4) The formation of eutectic-melting and micro-fissuring reduced together with strength and ductility of welded joints, and resulted in a typical brittle fractures.
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  • On Reaction Stress
    Yoshikazu Moriwaki, Fujino Masayuki
    1969 Volume 38 Issue 6 Pages 582-592
    Published: June 25, 1969
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    In previous paper the intensity of restraint (K) was clarified quantitatively on the X section member built-up by intermittent weld and the correlation between K of the X section members and those of various cracking test specimens could be established.
    The experiments were carried out to determine the reaction stress ((σw)t=∞) of the weld joints of all X section members from measuring the dislocation (displacement) (η) and the throat thickness (hw) of weld joints.
    The reaction stress ((σw)t=∞) can be expressed by the following equation,
    (σw)t=∞=K⋅η√hw
    where η is the average dislocation value and hw is the
    average throat thickness of weld joints.
    The results obtained are summarized as follows;
    1) The intensity of restraint (K) is concerned with the reaction stress ((σw)t=∞) by linear relation, when K is less than 500 kg/mm-mm. The intensity of restraint being greater than 500 kg/mm-mm, however, the relation between K and (σw)t=∞ changes from linear to courved one.
    2) The critical intensity of restraint (Kcr) and the critical reaction stress ((σw)cr) depend upon the angle steel size i.e., they are in the curved range of the (σw)t=∞-K diagram on L-150 × 150 × 15, but they are in the linear bounds of the above diagram on L-250 × 250 × 25.
    3) And Kcr and (σw)cr do not influence the bead lentgh, but have an important effect upon the angle steel size.
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  • Fatigue Strength of Hot Galvanized Welded Joint of Various Steels and Different Welding Processes
    Isao Masumoto, Mitsumasa Iwata
    1969 Volume 38 Issue 6 Pages 593-600
    Published: June 25, 1969
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    It was shown in previous report that the fatigue strength of mild steel butt welded joint was improved by hot galvanizing. This experiment was performed to confirm this effect of hot galvanizing on high strength steel butt welded joint, butt joints by different welding processes and fillet welded joint.
    To make clear, whether this effect of hot galvanizing comes from coated zinc itself or it is a thermal effect of heating in zinc bath and cooling in water, the fatigue strength of welded joints, which were dip-heated in zinc bath as well as hot galvanized but had no zinc coatings, was investigated.
    The results obtained are summarized as follows;
    1) Fatigue strength of 60 kg/mm2 and 80 kg/mm2 high strength steel butt welded joints is also improved by hot galvanizing.
    2) Fatigue limit of hot galvanized welded joint of mild steel is nearly the same as that of plain base plate.
    3) Only dip-heating in zinc bath and cooling in water is also effective to improve fatigue strength of welded joint. But the degree of the improvement by dip-heating is lower than that by hot galvanizine.
    4) A difference of welding processor the contour of weld bead has nothing to do with this effect of hot galvanizing.
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  • Yugoro Ishii, Tadao Onzawa, Toshiaki Oinuma, Makoto Murakoshi
    1969 Volume 38 Issue 6 Pages 601-607
    Published: June 25, 1969
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Dissimilar metals were bonded by using linear explosive and the constitution of fusion layer of bonded boundary was determined by X-ray microanalyser. The combination expected to form an intermetallic compound was estimated by X-ray diffractometer. The following results were obtained:
    1) The fusion layer of combination (Ag-Cu, Cu-Ni, etc.) which was expected to make eutectic reaction or produce a solid solution formed a uniform solid solution.
    2) The combination giving an intermetallic compound in equilibrium diagram was investigated by X-ray diffractometer. It was ascertained from X-ray diffraction pattern that the fusion layer consisted of an intermetallic compound. To determine the variety of intermetallic compound was difficult, because X-ray diffraction line was weak. An intermetallic compound of which the constitution resembled the experimental constitution of fusion layer was formed.
    3) The fusion layer expected to fuse and mix existed on the bonded boundary of Ag-Fe in a un-solid solution (photo. 8), but the constitution was uniform.
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  • Tadato Fujimura, Chozaburo Nakazaki, Hiroshi Namatame
    1969 Volume 38 Issue 6 Pages 608-614
    Published: June 25, 1969
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The fast-neutron irradiation embrittlement of structural steels is an important problem in the design of the pressure vessel of a nuclear power reactor. Many studies have been made on the irradiation embrittlement of steels in foreign countries.
    In Japan, plans are also in progress on the irradiation tests of domestic structural steels, and some have already been carried out by Research Commitee of Irradiation Embrittlement of Steels, The Iron and Steel Institute of Japan, acting as the center's.
    The present paper shows a part of above studies, the results of irradiation tests with JRR-2 of JAERI and also of the postirradiation tests of domestic steels, namely ASTM A302B steel, aluminium-killed steel and their weld metals.
    The contents of this paper include (1) irradiation condition of JRR-2, (2) test rig for irradiation, (3) apparatus for the post-irradiation test, and (4) results of the irradiation embrittlement tests and tensile test.
    The results obtained are as follows:
    (1) The transition temperature shifts for brittle fracture at 6-9 n/cm2 neutron doses were 67°C on A302B base metal, 107°C on its weld metal and 95°C on its bond metal.
    (2) The change of tensile property due to neutron irradiation in aluminium-killed steel was larger than in A302B steel.
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  • Isamu Ueda, Masaaki Miyake, Masaaki Kawamura
    1969 Volume 38 Issue 6 Pages 615-622
    Published: June 25, 1969
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    There are three fundamental points to understand the wettability of molten soders. Namely,
    (a) The magnitudes of surface energy in mother metal or molten solder and interfacial energy of mother metal/molten solder are closely related to the propriety of wettability.
    (b) The alloying tendency between mother metal and molten solder or the magnitude of diffusion power of molten solder to mother metal is related to propriety of wettability.
    (c) The magnitudes of alloying energy or potential energy due to gravity are related to propriety of wettability.
    Generally, wettability varies with chemical composition of soft solders, fluxes, mother metals and surface condition, heating temperature or atmosphere. And necessary condition to get perfectly wet is the following equation.
    σs>σLSL⋅cosθ
    where σs; surface tension of mother metal.
    σLS; interfacial tension of solder/mother metal.
    σL; surface tension of solder.
    θ; equilibrium contact angle of solder/mother metal.
    Accordingly, in this test, authors have measured the spread area of solders combined with various fluxes and investigated the surface tension of mother metal, interfacial tension of solder/mother metal, surface tension of solders and viscosity of fluxes which have effect on the magnitude of spread area. As fluxes, ZnCl2, ZnCl2-SnCl2⋅2H2O, ZnCl2-NH4Cl, ZnCn2-NaCl, ZnCl2-KCI binary system fluxes and ZnCl2-SnCl2. 2H2O-NH4Cl ternary system flux are used. As solders, Sn-Pb, Pb-Cd, Sn-Bi, Sn-Cd, Sn-Zn and teernary solders are used.
    The results obtained from above investigations are as follows.
    (1) The spread area of eutectic solder at 350°C is little affected by flux such as ZnCl2-NaCl or ZnCl2-KCl.
    (2) The spread areas of Sn-Pb, Zn-Cd and Pb-Cd solders are comparatively satisfactory with ZnCl2 flux at 350°C. And in the case of Sn-Pb, Sn-Bi, Sn-Cd, Pb-Sn and Pb-Cd, i.e., two component solders, the spread area with ZnCl2:NH4Cl=2:1 binary flux at 350°C has a comparativey larger value than with ZnCl2 only.
    (3) With regard to the effects on spread area of the 3rd alloying metals in eutectic solders, the effects of these metals are not a negligible factor; especially, the spread area is increased by addition of As to eutectic solders. As the quality is deteriorated by addition of As, Bi and Zn, addition of these metals is to be avoided.
    (4) When Sn70Wt%-Zn30Wt%, Sn70Wt%-Bi30Wt%, Sn70Wt%-Pb30Wt% and Sn70Wt%-Cd30W% i.e., two component solders combined with ZnCl2;SnCl2⋅2H2O=2:1 and ZnCl2:SnCl22H2O:NH4Cl=2:1:1 system fluxes are used, the temperature dependency of the spread area of solders is relatively high in range from 300 to 400°C. The spread area of above solders combined with ZnCl2:SnCl2⋅2H2O:NH4Cl=2:1:1 ternary flux has a larger value than ZnCl2:SnCl2⋅2H2O=2:1 binary flux.
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  • Hideo Mikashima, Shizuo Mukai, Tamotsu Hashimoto
    1969 Volume 38 Issue 6 Pages 623-630
    Published: June 25, 1969
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Recently, with the progress of a large scale construction, various welding methods for heavy steels have been developed and utilized. Most of them, however, use a large heat input in one pass welding, so that the cooling rate of deposit metal is very slow and the deterioration in notch toughness based on growth of the crystal grain hoses a problem.
    Although notch toughness of deposit metal is improved by full annealing after welding, addition of some alloy elements and application of supersonic vibration for the refinement of crystal grains under as-welded condition have been tried so far. But it is considered that the latter is limited in the range of application and grain refinement effects, while further examinations are required for the former.
    Seeing that macro-and micro-structures of deposit metal closely resemble that of cast steel, the effects of Ti and Zr on the micro-structure and impact value of cast steel were investigated to make some indirect considerations about the effects of those elements on the notch toughness of welding deposit metal.
    Both of Ti and Zr have acted as nucleus in the solidification of molten metal and have refined austenite grain. But, under addition of Ti, the hardness of ferrite grain remarkably increased and the impact value not improve. On the other hand, as the result of addition of Zr which was a considerable refining elemement as austenite grain little increased the hardness of ferrite grain and the impact value markedly rose up to 0.04% Zr.
    As the average size of the cleavage fracture facets observed in impact fracture face corresponds to that of austenite grains, it is concluded that the improvements of impact value through addition of Zr is attributed to the refinement of austenite grains without increasing the hardness of micro-structure.
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  • 1969 Volume 38 Issue 6 Pages 643-654
    Published: June 25, 1969
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • 1969 Volume 38 Issue 6 Pages Plate1-Plate2
    Published: June 25, 1969
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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