JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 48 , Issue 7
Showing 1-18 articles out of 18 articles from the selected issue
  • Takuro Kobayashi
    1979 Volume 48 Issue 7 Pages 445-448
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
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  • Toshikazu Shimoyama, Osa Matsumoto
    1979 Volume 48 Issue 7 Pages 449-458
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
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  • Yoshikazu Kuriyama, Takesuke Kohno
    1979 Volume 48 Issue 7 Pages 458-467
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
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  • Keizo Ohnishi, Hisashi Tsukada, Komei Suzuki, Masamitsu Murai, Hisashi ...
    1979 Volume 48 Issue 7 Pages 468-475
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    A possibility of cold cracking in the heat affected zone (HAZ) of heavy section steel forging during stainless steel overlay cladding was investigated.
    The results of the study obtained are summarized as follows:
    1) The hydrogen embrittlement of HAZ below 120°C is remarkable, especially at room temperature. Even a small amount of hydrogen of about 1.5 ppm decreases the lower critical stress.
    2) The hydrogen contained in the deposited stainless steel metal diffuses into HAZ of the base metal and is able to be a source of hydrogen induced cracking.
    3) Over 0.5 % restricted strain, the hydrogen induced cracking will be occurred in HAZ, if the welding conditions, such as preheat and postweld heat treatments, are not appropriate.
    4) It is necessary to maintain the preheat temperature of 120°C or over during entire welding process, in order to prevent the hydrogen induced cracking under the heavily restricted condition in the large heavy section steel forgings.
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  • Tomohiko Shida, Hisanori Okamura, Hisanao Kita, Takamitsu Nakazaki
    1979 Volume 48 Issue 7 Pages 476-482
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    Relations between occurrence of vertical cracking defects, solidification structures and solidification patterns, bead shapes and welding conditions were investigated in flat position electron beam welding of heavy section 0.17C steel and 2 1/4 Cr-1 Mo low alloy steel plates. Penetration depths up to 80 mm were investigated. Models of welding phenomena were proposed to explain occurrence of the vertical cracks. It was concluded that,
    (1) 21/4 Cr-1 Mo steel was more liable to cause vertical cracks than 0.17 C steel. It was possible, however, to obtain a weld bead composed of stable type I (most stable) and type II (stable) solidification structures by selecting a proper welding condition.
    (2) The proper welding condition should be selected to satisfy the following requirements,
    (i) slow welding speed (in this experiment 0.2 m/min.)
    (ii) narrow bead width
    (iii) formation of a wedge-shaped bead (small value of "bead form factor")
    Oscillation of the electron beam in the X (in the line of welding) direction was effective to broaden the range of selection of welding conditions.
    (3) The degree of lag of solidification front was reduced by selecting a slow welding speed and parameters to form a wedge-shaped bead. This reduction of lag seemed to be one of main reasons that prevented the formation of type III (unstable structure with segregation) and type IV (vertical crick) solidification structures.
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  • Shigenori Kumakura, Yasuo Nasu, Takenobu Takeda, Takeo Sato
    1979 Volume 48 Issue 7 Pages 482-488
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    The spot welding of low carbon steel sheets was carried out using an electrode tip of a rectangle in shape. The specimen obtained had a uniform and cylindrical weld nugget in the direction of the width of the sheet, so that the welded structure was observed on the side of the specimen and the structural changes in the fatigue process were examined without cutting the specimen.
    The fatigue test was performed under the pulsating tension-shear load, and the initiation and the propagation of a crack were examined by an optical microscope. The microcracks were initiated in the slip bands formed near the edge of the junction in the heat affected zone and developed into the macrocrack along the cross section of the specimen perpendicular to the direction of the loading.
    Furthermore, it was found that the bending moment in the longitudinal direction of the specimen resulted from the offset of the overlapped part decreased considerably at a quarter cycle of the cyclic loading with an increase of a plastic deformation in the base metal.
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  • Hiroya Taguchi, Mitsuaki Haneda, Shoji Imanaga, Itsuhiko Sejima
    1979 Volume 48 Issue 7 Pages 488-493
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    Plasma arc welding with filler wire addition has been used for various purposes in industry. However, there have been few studies on metal transfer in plasma arc with filler wire.
    This paper deals with the characteristics of the metal transfer mechanism of the filler wire in the plasma arc, and observation of the droplets transfer. The metal transfer was observed by high speed camera and the wirework voltage was recorded by oscillograph.
    In case of plasma arc, the droplets transferred to the molten pool with a streaming transfer which was not observed in TIG arc. The liquid metal at the wire tip was bent downward by the plasma jet and transferred to the workpiece without contact to the molten pool.
    As a result, plasma jet stream was found to be the main factor causing the streaming transfer.
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  • Yoshiaki Arata, Katsunori Inoue
    1979 Volume 48 Issue 7 Pages 493-498
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    Theprinciple for the optical joint configuration sensing method developed by authors is described. In this method, the joint configuration near by the welding arc, generation point is projected on the screen of the image receiver of conventional type which is composed of two lenses and focussing screen. The image on the screen can easily be converted into electrical signal and the on-line joint configuration sensing during arc welding can be performed.
    The sensing characteristics on the obtained image are investigated by assuming a primary geometrical model and several limits of sensing ability are estimated qualitatively and quantitatively. The results are compared with the experiment.
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  • Isao Masumoto, Kazuo Matsuda, Masayoshi Hasegawa
    1979 Volume 48 Issue 7 Pages 498-504
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    All types of the humid coated electrode except low-hydrogen type produced sound weld metals in the experimental range of absorbed water contents, as described in the previous report. And in this study on the porosity by low-hydrogen type electrode were investigated with supply of complementary shielding gas, addition of deoxidizer in weld metal, rebaking of humid coated electrode and chemical analysis of blowhole gases in deposited metal.
    The experimental results were as follows:
    1) The porosity could not be prevented by CO2 or Ar complementary shielding gas. Therefore, the cause of this porosity was not to be ascribed to nitrogen or oxygen by invasion of air.
    2) The porosity could not be prevented by addition of various deoxidizing elements. Therefore, the cause of this porosity was not to be ascribed to carbon monoxide reaction in weld metal.
    3) The sound weld metal was obtained by rebaking of the coated electrode at 150 or 400°C for 1 or 2 hours.
    4) The gases in blowhole consisted mainly of hydrogen (ca. 80.0 %), some amount of nitrogen (ca. 3.0 %) and oxygen (ca. 1.1 %). But carbon monoxide was hardly determined.
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  • Kunihiko Satoh, Toshio Terasaki, Yashuo Yamashita
    1979 Volume 48 Issue 7 Pages 504-509
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    This paper deals with the effect of welding conditions on hydrogen concentration at the root of weld metal. The calculations of hydrogen concentrations in weld metal and HAZ are done by means of two dimensional finite difference method based upon hydrogen diffusion equation which is composed of temperature, stress and strain terms.
    The results obtained in this report are summarized as follows:
    (1) Hydrogen diffusion equation and numerical method for hydrogen concentration at the root of joint are described.
    (2) On comparison of hydrogen concentrations among single-bevel-groove, double-Vee-groove and implant specimen, hydrogen concentration of single-bevel-groove turns out to be largest.
    (3) The influence of stress term on hydrogen concentration is large as compared with strain term.
    (4) Hydrogen concentration at the root of joint increases with yield strength of weld metal increasing and transformation temcerature of cooling process decreasing.
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  • Ikuo Okamoto, Tadashi Takemoto, Chikara Fujiwara
    1979 Volume 48 Issue 7 Pages 510-515
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    The corrosion behaviour of silver brazed SUS 304 stainless steel has been studied in 0.4M NaCl solutions with additions of CuCl2⋅2H2O up to 0.05M. Effects of filler alloy composition and copper in solutions on the corrosion behaviour were discussed. Simultaneous corrosion of filler alloy and stainless steel at brazed interface took place. To evaluate each corrosion rate, a new specimen shape, filler alloy was flown along the stainless steel groove with the radius of 2.5 mm, was used. Major elements of filler alloys and stainless steel except silver were dissolved into the solution. The corrosion of filler alloy was the preferencial dissolution of α-Cu (mainly Cu-Zn) phase. Filler alloys containing cadmium and indium had lesser corrosion resistance than Ag-Cu-Zn ternary alloys and exhibited rapid interfacial corrosion.
    Corrosion rates of filler alloys and interface were found to depend greatly on the copper content in chloride solution. Copper increased the corrosion rate mainly by the enhancement of cathodic reaction. Over the range of this study, BAg-4 filler alloy was suitable for the corrosion resistant SUS 304 braze joint.
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  • Shigetsugu Asakura, Hiroshi Wachi
    1979 Volume 48 Issue 7 Pages 515-519
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    The effects of Ni contents in 13 Cr cast steel and coated electrode with 2-6 % of Ni added for improvement of weldability on the crack sensitivity were investigated using the slit type cracking test specimens. The results of these test are sununerized as follows.
    (1) Crack sensitivity of the HAZ remarkably decreases when Ni contents of base metal is increased from 2% to 6%.
    (2) In case of no preheating, weld cracks could be perfectly prevented when 13 Cr-Ni base metal with Ni added by 6 % and 13 Cr type electrode (containing Ni 2.5-4 %) were used.
    (3) In the 13 Cr-Ni cast steel containing Ni 4 %, weld cracking was not observed when the preheating temperature was above 100°C and 13 Cr type electrode (containing Ni 2.5-4 %) was used.
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  • Kunihiko Satoh, Toshio Terasaki
    1979 Volume 48 Issue 7 Pages 520-525
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    Implant test has following merits: Data on cold cracking susceptibility are easily obtained from small size specimens as compared with self-restrained weld cracking test like Lehigh test, RRC test etc..Implant test is valuable in economical sense. However, implant test has its inherent disadvantage; several experiments have suggested that it has been apparently difficult to apply directly the critical stress and/or the critical cooling time obtained from implant test to welding procedure in RRC test which is considered as welded joint of real structures. In the present report, attention is forcussed to determine correlation between RRC test and implant test. Firstly implant-and RRC-test are carried out under various conditions of materials and preheat temperatures. Secondly two dimensional finite element method based on elasto-plastic theory is carried out to find out the parameter determing initiation of cold cracking from the standpoint of engineering.
    The conclusions obtained in this report are summarized as follows:
    1. It is concluded from comparison of implant-test results with RRC-test results that the local stress in loading direction at region where cold cracking starts becomes engineering parameter of cold cracking.
    2. Correlation between the critical net stress of implant test (σIpm)cr and the critical net stress of RRC test (σRRC)cr is given in following equation from engineering sense stand point
    Ipm)cr = (K1)RRC/(K1)lmpRRC)cr
    where, (Kt)Imp is stress concentration factor of implant specimen and (Kt)RRO is stress concentration factor of RRC specimen.
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  • Yukio Ueda, Iwao Nishimura, Hideaki Iiyama, Naomichi Chiba, Keiji Fuku ...
    1979 Volume 48 Issue 7 Pages 525-531
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    Lamellar tearing of opening type occasionally occurs in multipass welded corner joints. Effects of gas cutting for the edge surface of the vertical plate and shapes of grooves on the occurrence of the lamellar tearing are investigated experimentally and theoretically. The main results obtained in this study are as follows.
    (1) In the cases where the edge surface of the vertical plate is prepared by gas cutting or machine, the transverse. welding residual stress on the edge surface of the vertical plate reaches approximately the yield point at the position 10 mm away from the toe and the lamellar tearing occurs, when the intensity of bending restraint increases. No difference between these cases is observed in the critical intensity of bending restraint for lamellar tearing.
    (2) In order to reduce transverse welding residual stresses and to prevent the occurrence of the lamellar tearing, it is effective to use such a groove that the edge of the vertical (web) plate is projected out of the upper surface of the flange plate or that the vertical plate is cut obliquely.
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  • Isao Masumoto, Takeshi Shinoda, Jun Takano, Tsuneo Suzuki
    1979 Volume 48 Issue 7 Pages 532-536
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    An algorism and program for determination of welding parameters of CO2 horizontal fillet welding is studied. The proposed program is applicable to the globular transfer condition, of 1.6 mm wire diameter.
    Calculated parameters were confirmed experimentally to give good bead appearance from 5 to 8 mm in leg length.
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  • Takehiko Watanabe, Isao Okane, Ken Sasabe
    1979 Volume 48 Issue 7 Pages 536-542
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    The basic experiments for brazing on a large number of combinations of base metal and brazing filler metal were carried out to investigate the relationship between wettability and bond strength of brazed joint, which is being thought the most primary and important problem in brazing phenomena.
    In this report, the experimental results of contact angle and bond strength and metallurgical structure of bonded layer were shown, and fracture path by tension test of brazed joint was inspected.
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  • Toshie Okumura, Takahide Tanaka, Yoshinori Ito, Hajime Nashiwa
    1979 Volume 48 Issue 7 Pages 542-550
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    The mechanical properties of low silicon 80kg/mm2 high tensile strength steel were investigated. The effect of lowering silicon content on the properties of welds was confirmed using low silicon 80kg/mm2 high tensile strength steel plate manufactured by the practical converter and the mill. The results obtained are summarized as follows.
    (1) Lowering silicon content below 0.1wt%, the toughness of weld bond and the lamellartearing susceptibility are improved.
    (2) As the result of the improvement of weld bond Charpy impact toughness and fracture characteristics of welds, the allowable weld heat input can be expanded. High Charpy impact toughness of weld bond can be obtained without nickel addition in high heat input welding same as nickel addition steel.
    (3) The improvement of weld bond toughness by lowering silicon content is due to the improvement of microstructure, especially the elimination of high carbon martensite island formation in high heat input welding.
    (4) The improvement of lamellartearing susceptibility is due to the decreace of the total length of nonmetallic inclusions by lowering silicon content.
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  • Shizuo Mukae, Mituaki Katoh, Kazumasa Nishio, Micho Egashira
    1979 Volume 48 Issue 7 Pages 550-556
    Published: July 05, 1979
    Released: August 05, 2011
    JOURNALS FREE ACCESS
    The relationship between static tensile properties and weld solidification structures were studied. Tensile test was performed on a base metal and weld metals of A5052-O aluminum alloy sheet at test temperatures of room temperature, -20; -70 and -196°C. Tensile speeds were. 5 and 200mm/min.
    With decreasing the test temperature, the tensile strength and also the elongation of the base metal and the weld metals increased. The tensile strength of columnar crystal had almost the same value as that of equiaxed dendrite. These values agreed. approximately with that of the base metal at each test temperature. The tensile strength of feathery crystal had smaller value than that of the other solidification structures and was about 90% of that of the base metal.
    When a longitudinal-bead tensile test was performed, little difference was observed in the elongation of each solidification structure. The value of elongation was about 75% of that of the base metal. In a transverse bead tensile testing, the elongation of the feathery crystal was considerably smaller than that of the other solidification structures, and was about 60% of the that of the base metal.
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