JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 41, Issue 6
Displaying 1-9 of 9 articles from this issue
  • Yoshiaki Arata, Katsunori Inoue
    1972 Volume 41 Issue 6 Pages 613-648
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Takuro Kobayashi, Takeshi Kuwana, Masahiro Koyama
    1972 Volume 41 Issue 6 Pages 649-662
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Using six series of aluminum-alloy electrode wires, bead-on-plate specimens were made in Ar-N2 mixed gas atmospheres. The effects of titanium, zirconium, silicon, copper, zinc and magnesium in electrode wires on the surface appearance, depth of penetration, porosity and nitrogen content of weld metals were systematically studied.
    The main results obtained are as follows:
    (1) Al-Ti, Al-Zr, AI-Si and Al-Cu wires are prone to cause puckered welds at PN2=0.1-0.5 atm (PAr=0.9-0.5 atm).
    (2) Zinc and magnesium are effective alloying elements to prevent puckering phenomena in Ar-N2 atmospheres.
    (3) Use of Al-Zn and Al-Mg wires gives rise to good profiles of penetration even in nitrogen- rich Ar-N2 atmospheres.
    (4) Use of Al-Ti, Al-Zr, Al-Si and Al-Cu wires increases the porosity of aluminum welds in Ar-N2 atmospheres.
    (5) The nitrogen content of weld metals decreases with increasing Ti, Zr, Si, Cu, Zn and Mg contents in electrode wires.
    (6) From the view point of welding process, Al-Zn or Al-Mg electrode wires are fit for the Ar-N2 gas metalarc welding of aluminum.
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  • Itsuro Tatsukawa, Akira Oda
    1972 Volume 41 Issue 6 Pages 663-674
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Metallurgical aspects of the problem on explosive 18Cr-8Ni stainless clad steel heated at high temperatures have been investigated by means of microhardness test, microscopic examination, electron-microprobe technique and X-ray diffraction analysis. The main results are as follows:
    Heating above 500°C for long time causes a diffusion of carbon atoms from mild steel into stainless steel, and consequently carbon is highly concentrated at the boundary layer of stainless steel. At about 600° to 700°C, chromium carbides, mainly Cr7C3, precipitate very closely in the carburized layer with remarkable hardening. As the temperature increases up to 900°C, Cr23C6 and σ-phase appear besides Cr7C3 and they disperse into stainless steel followed by a decrease in hardness. Also, another thin layer of lower chromium and nickel contents than original composition of stainless steel forms with no precipitates at bond interface since both chromium and nickel atoms diffuse from stainless steel into mild steel. All the precipitates dissolve fully in austenite at 1100°C. Short-time spot smelting by TIG arc causes a little diffusion of carbon and precipitation of carbides at bonded zone and does a layer of α-γ phases in the heataffected stainless steel of clad metal.
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  • Shigeo Akashi, Mitsuhiro Natsume
    1972 Volume 41 Issue 6 Pages 675-686
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The objective of this study was to investigate the root-cracking in welded joints with restraint and to find the suitable welding procedure corresponding with the intensity of restraint.
    Large H-type specimen and variable restraint equipment were used to simulate four steps of restraaint, and five kinds of steels were submitted to testing.
    The conclusions are as follows:
    (1) Welded joint length of at least 150 mm appeared to be necessary for the crack testing from the study of stress distribution of H-type specimen.
    (2) The ranges of restraint intensity free from root-cracking were found as shown in Fig. 13. It is noteworthy that the low alloy 50 kg/mm2 strength steels have a high crack susceptibility.
    (3) Two or three passes welded under 10 minutes intervals are as much efficient as preheating to prevent root-cracking, whereas they have no effect to decrease the restraint stress.
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  • Misao Sawairi, Ryohei Tanaka
    1972 Volume 41 Issue 6 Pages 687-694
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    An experimental study was made on the weldability of 18Cr-10Mn stainless steels containing high concentration of nitrogen up to about 0.8%, prepared by a high-pressure melting process in nitrogen atmosphere. Main results obtained are as follows.
    (1) In the arc welding of high nitrogen l8Cr-10Mn stainless steels, if ordinary welding conditions recommended for welding commercial austenitic stainless steels are adopted, we shall usually be able to get excellent and sound welded joints.
    (2) In case of welding by using the electrode having the same composition, the tensile strength of welded joints increases in proportion to the nitrogen content of base metals. This strengtheing in the welded joints depends upon the extent of nitrogen diffusion, which occurs from the base metal to the welded metal.
    (3) The decrease of impact strength in heat-affected zone scarcely occurs even in the steel containing about 0.8% nitrogen.
    (4) While the base metal is melting, the nitrogen contained in the base metal diffuses and blows out of the metal a little. Consequently, in the base metal containing high concentration of nitrogen i.e. more than 0.65%, blowholes in the weld deposit increase and the concentration of nitrogen in the heat-affected zone decreases a little.
    (5) But, the decrease of nitrogen content in the base metal occurs only in the limited portion near the weld bond, and the amount of the decrease is small. Therefore, in the steels containing nitrogen less than about 0.65%, the decrease of the nitrogen content scarcely influences the mechanical properties and the microstructures of the welded joints.
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  • Fracture Characteristics of High Heat Input Submerged-Arc Weld Bond for 80kg/mm2 HTS
    Makoto Sato, Hajime Nakasugi
    1972 Volume 41 Issue 6 Pages 695-699
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    A study was made on prevention of brittle fracture in a high heat input welded joint for 80kg/mm2 high tensile steel and a metallurgical investigation into the improvement of cleavage fracture strength of weld bond was carried out.
    In this report the fracture characteristics of conventional HT80 steels' welded joints welded with 80 KJ/cm heat input are clarified. They fracture at weld bond in a brittle manner at 15-20°C.
    And the clue to prevention of brittle fracture is discussed according to fracture analysis diagram.
    It is stressed that the solution to this problem lies in the fact that the compound microstructure of low carbon bainite and low .carbon martensite has superior notch toughness and higher yeild stress.
    Namely, the higher the notch toughness and the higher the yield stress are in weld bond, the tendency of weld bond brittle fracture becomes the lis less conspicuous.
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  • Junichiro Tsuboi, Noboru Sakamoto, Kazuhiko Miura
    1972 Volume 41 Issue 6 Pages 700-708
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    It is often observed that the shape of horizontal fillet weld bead is influenced by welding variables and flux.
    From the viewpoint of the interfacial tension phenomena, this study was done to investigate the relation among the shape of horizontal fillet weld bead, welding variables and flux composition.
    Firstly, a theoretical consideration on the formation of horizontal fillet weld bead was made on the assumption that the shape of weld bead would be determined by the balance of interfacial tensions between slag, molten metal and solid metal, gravity of liquid metal and so forth.
    Secondly, the effect of interfacial tension between slag and metal on the bead shape was examined experimentally.
    The interfacial tension was measured by a new method proposed in this paper.
    That is, flux and wire were melted by TIG arc in a copper crucible cooled with water. The interfacial tension was calculated from the shape of a frozen steel drop.
    The following results were obtained:
    (1) The shapes of horizontal fillet weld bead are classified into three types in submerged arc welding.
    (2) The main factor which determines the bead shape of submerged arc horizontal fillet weldindg is the interfacial tension between slag and metal.
    (3) In order to get a good shaped horizontal fillet bead, it is necessary to use a flux which exhibits as large values as possible of interfacial tension and specific gravity.
    But, according to theoretical consideration, more than 9.5 mm of leg length could not be attained for the horizontal fillet bead welded in one pass.
    (4) It was confirmed that the interfacial tension between molten slag and molten metal was able to be measured by the shape of a frozen steel drop.
    (5) With the above-mentioned method, the interfacial tension between weld slag and wled metal was measured.
    The values of the interfacial tesion were 1250 dyne/cm for the maximum case and 750 dyne/cm for the minimum case, respectively.
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  • Investigation for Commercially Used Constructional Metals and Alloys
    Tomio Senda, Fukuhisa Matsuda, Genta Takano, Kiyoshi Watanabe, Tadaaki ...
    1972 Volume 41 Issue 6 Pages 709-723
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    In fusion welding of constructional ferrous and non-ferrous materials solidification cracking frequently occurs in the weld metal when a great deal of distortion and shrinkage takes place in the parent and weld metals due to a local rapid weld heat cycle. The occurrence of this solidification cracking, which is a kind of hot cracking, often gives rise to serious problems for some constructional materials from a view-point of weldability.
    Meanwhile those constructional materials including commercially pure metals have a brittleness temperature range during solidification whose ductility is very low to cracking.
    The properties in the solidification brittleness range such as temperature difference, minimum ductility and shape of ductility curve depend upon the kind and amount of impurities or alloying elements in the materials. Increasing the temperature interval and decreasing the minimum ductility are considered to increase the susceptibility of solidification cracking for the material in general.
    Unfortunately, however, there are few reports, so far, concerning the properties in the solidification brittleness range during welding of the constructional materials in spite of their close relation to solidification cracking.
    In this report authors have firstly investigated the nominal susceptibility of solidification cracking during TIG arc bead-on-plate welding for various constructional materials of carbon steels, low alloy high tensile strength steels, austenitic stainless steels, aluminum and aluminum alloys and brass, using the Trans-Varestraint Tester which was modified from the original Varestraint. Secondly, utilizing the relationship between the maximum crack length occurring in the center of weld metal with the Trans-Varestraint Test and the temperature distribution during welding which was actually measured, the properties of the solidification brittleness range have been investigated for the weld metals of the materials.
    Lastly, authors have proposed new indices, the critical strain rate for temperature drop (CST), which reasonably evaluates the solidification crack susceptibility of material during welding and the critical strain rate to time (CSS), which is easy to measured and is substituted for (CST) under a limited condition.
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  • 1972 Volume 41 Issue 6 Pages 734-741
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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