JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 42 , Issue 10
Showing 1-7 articles out of 7 articles from the selected issue
  • Hiroshi Tamura, Takehiko Watanabe
    1973 Volume 42 Issue 10 Pages 966-977
    Published: October 25, 1973
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    Mechanism of grain-boundary liquation cracking in weld heat-affected zone of HT100 (HY 130 type) high strength steel was studied using a high temperature microscope and an electron probe X-ray microanalyser.
    The main understandings are as follows:
    (1) For test high strength steel, low-melting point liquation of grain boundary was obviously observed at the temperature of about 1355°C-1360°C in rapid heating (heating rate about 270°C/sec.). This temperature was extremely lower than the solidus temperature (about 1440°C) in rapid heating.
    (2) In the heat-affected zone of the test high strength steel, there was formed some unetched “whitelike grain boundary”, so-called “heavy boundary” mainly due to Cr and Ni enrichments.
    The width of these boundaries becomes wider with an increasing peak temperature, and liquation was observed in these boundaries when heated to peak temperature over about 1360°C.
    (3) In “white-like grain boundaries” arrays of MnS particles were also observed frequently.
    By direct observation with a high temperature microscope, it was recognized that these precipitated MnS particles were formed during rapid cooling at the temperature below about 1000°C.
    (4) It was presumed that the most important factor to cause the grain-boundary liquation in the heataffected zone of the test high strength steel was the low-melting point eutectic reaction between Cr and Ni elements which had been swept up and enriched to the grain boundary.
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  • Yoneo Kikuta, Nobuaki Miyao, Saijiro Yoshida, Hiroshi Tanimoto
    1973 Volume 42 Issue 10 Pages 978-989
    Published: October 25, 1973
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    The followings are the test results of the bead shaping in Lay Down Welding.
    1. All of the factors, viz. (1) kind of the covering, (2) the covering composition, (3) the eccentricity ratio of electrode, (4) arc current, (5) groove angle of base metal, and (6) welding position as welding conditions, influence on the bead shaping.
    2. As to the relation between 3 factors (the covering composition, the eccentricity ratio of electrode and arc current in welding condition) and good bead area in flat and horizontal fillet welding; By increasing iron powder in the coverings, decreasing the gas materials and enlarging the eccentricity ratio of electrode, the currency for good bead area becomes higher and the extent of current become enlarged. The good bead area in horizontal fillet welding become narrower as compared with the V groove (flat fillet) welding.
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  • Isamu Koizumi
    1973 Volume 42 Issue 10 Pages 990-995
    Published: October 25, 1973
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    Studies were conducted to investigate the effect of chemical elements, grain size and degree of cold working on the HAZ cracking of 75 Ni-15 Cr-Fe alloy.
    The results obtained in this report are as follows:
    1. Increasing Mg content of 75 Ni-15 Cr-Fe alloy, the HAZ cracking occures remarkably.
    2. C, Ti and Al do not influence on the HAZ cracking within the content of specification value.
    3. Austenitic grain size and cold working do not effect remarkably on the HAZ cracking of 75 Ni-15 Cr-Fe alloy.
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  • Tomio Senda, Fukuhisa Matsuda, Hiroji Nakagawa
    1973 Volume 42 Issue 10 Pages 996-1006
    Published: October 25, 1973
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    Theoretical Investigation is discussed on the change in liquid composition among growing cells or cellular dendrites in Fe-S-X ternary alloy, where X is the third element. Main conclusions obtained are as follows:
    1) Under the condition that the liquid among the growing cells or cellular dendrites is completely mixed and the diffusion in solid is negligible, the liquid composition in Fe-S-X ternary phase diagram follows the “changing curve in composition” given by:
    Cls={CSI/CXX(1-kS)/(1-kX)}CIX(1-kS)/(1-kX)
    where Cls and Clx are the concentrations of S and X in liquid respectively, CsI and CxI are these initial concentrations, and ks and kx are these equilibrium distribution coefficients.
    2) The law of coincidence for the change in liquid compositions in alloys of various compositions is given by:
    CXI(1-kS)/(1-kX)/CsI=constant
    Alloys whose compositions satisfy this equation undergo the same change in liquid composition, and therefore sulphides formed have same composition.
    3) In the case of Fe-rich Fe-S-O alloy, the changing curve in composition, until the liquid composition reaches the miscibility gap in Fe-S-O diagram, is given by:
    Cl/S=(CsI/CoI)Clo
    where ClO and Cor are the concentration in liquid and initial concentration of O respectively.
    4) The law of coincidence in Fe-rich Fe-S-O alloys is given by:
    Cor/Csr=constant
    5) In the case of Fe-rich Fe-S-Mn alloy, the changing curve in composition, untill the liquid composition reaches the eutectic curve crystallizing (Mn, Fe)S in Fe-S-Mn diagram, is given by:
    in the region of δ solidification
    Cls=(CSI/CMI3) ClM3
    in the region of γ solidification
    ClS=(CsI/CMI5)ClM5
    where ClM and CmI, are the concentration in liquid and initial concentration of Mn respectively.
    6) The law of coincidence in Fe-rich Fe-S-Mn alloys is given by:
    in the region of δ solidification
    CMId3/CsI=constant
    in the region of γ solidification
    CMI5/CsI=constant
    7) In the case of welding the complete mixing of liquid and the negligible effect of diffusion in solid on the solute distribution in liquid are approximately estimated. Therefore it is considered that the changing curve in composition and the law of coincidence can be applied to the weld solidification.
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  • Kunihiko Satoh, Kenji Seo, Kenji Iwai, Daisuke Takahashi
    1973 Volume 42 Issue 10 Pages 1007-1017
    Published: October 25, 1973
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    This paper is concerned with the elasto-plastic analysis of thermal stresses and strains in weld metal of multi-pass butt weld. Analysis is performed based on the incremental theory of thermo-elasto-plasticity under one dimensionaly distributed temperature. Numerical calculations are made for two kinds of weld joint as shown in Figs. 1(b), (c), each of which corresponds to the behavior of the transverse and longitudinal section of weld joint respectively.
    Assumptions are made for heat flow that a rectangular distribution of initial temperature is given at the start of each pass and heat flow occurs only in y-direction. Another initial condition is also applied to the calculations that a line heat source is given at the start of each pass as shown in Fig.9.
    From the calculations are estimated successfully transient thermal stress and plastic strain distributions. Effects of weld conditions on residual stress and strain are clarified. Relations between plastic strain in back surface and angular distortion under several weld conditions are also obtained.
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  • Yasuhiro Nishio, Yasuyuki Yoshida, Kisaburo Tanaka, Zenichiro Okamoto
    1973 Volume 42 Issue 10 Pages 1018-1023
    Published: October 25, 1973
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    Strange silver white spot illustrated in photo. 2 appeared in the tensile test specimen of thick weld metal which is free from weld cracking. We studied the cause of the phenomenon, the result obtained is as follows.
    (1) Strange silver white spot in photo. 2 is enlarged fish eye.
    (2) Silver white spot in tensile specimen have two kind, one is fish eye, and the other is micro weld cracking.
    (3) Micro weld cracking includes small columnar structure and fish eye does not include it. Difficulties to judge the strange silver white spot in tensile specimen the micro weld cracking is solved by finding small columnar rstructure in fracture surface. i.e. Micro welding crack includes small columnar structure and fish eye does not include it.
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  • Takeshi Kanazawa
    1973 Volume 42 Issue 10 Pages 1024-1040
    Published: October 25, 1973
    Released: August 05, 2011
    JOURNALS FREE ACCESS
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