JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 44, Issue 6
Displaying 1-8 of 8 articles from this issue
  • [in Japanese]
    1975 Volume 44 Issue 6 Pages 449-450
    Published: June 05, 1975
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Download PDF (152K)
  • Sin-ichi Nisida, Hiroshi Yada, Hironori Yamamoto
    1975 Volume 44 Issue 6 Pages 451-458
    Published: June 05, 1975
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The mechanical properties of electron beam (EB) welded joints of various stainless steel sheets were investigated in comparison with those of TIG arc welded joints, especially from the view point of draw and formability.
    The main results obtained are as follows.
    1) The width of weld bead at the center of thickness is about 0.5 mm in EB welding and is about 4 mm in TIG arc welding. The grain growth in TIG arc weld bead is more remarkable than in EB weld bead in the cases of ferritic stainless steels.
    2) The draw and formability of EB welded joint are the same as those of base metal and superior to those of TIG arc welded joint.
    3) When the width of EB weld bead is on purpose widened, its proprties are deteriorated on the equal level of TIG arc welded joint.
    4) From 1)-3) etc, the reason why the properties of EB welded joint are better than those of arc welded may be attributed to the narrow width of EB weld bead. The change of properties of this weld bead is not revealed by the restraint of the base metal.
    Download PDF (7122K)
  • Atsushi Hasui, Yasuo Suga, Hideo Toma
    1975 Volume 44 Issue 6 Pages 459-465
    Published: June 05, 1975
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The feasibility of underwater overhead welding by gravity arc welding process is investigated. The 4 mm dia. coated electrodes of five types and SM41 steel base metal of 6 mm thickness are used. And it is ascertained that this process may be put to practical use. Main results are summarized as follows:
    (1) Sound weld can be obtained easily, if only proper welding conditions are selected. Especially high titanium oxide type, ilmenite type and lime titania type electrodes have relatively good weldability for overhead welding.
    (2) The range of proper welding conditions using the high titanium oxide type electrode seems to be relatively wide. For example the proper range of electrode angle is 45°-80° and the proper welding current 135-180 Amp.
    (3) Fillet welded joints got by high titanium oxide type, ilmenite type and lime titania type electrodes have sufficient tensile strength.
    (4) The maximum hardness of the weld got by overhead welding is lower than that by flat and vertical welding.
    (5) Cooling rate in overhead welding is lower than that in flat and vertical welding. For example, cooling rate at bond at 500°C is about 135°C/sec in overhead welding, 140°C/sec in flat and 205°C/sec in vertical.
    Download PDF (5751K)
  • Ueda Yukio, Eiji Takahashi, Keiji Fukuda, Keiji Nakacho
    1975 Volume 44 Issue 6 Pages 466-474
    Published: June 05, 1975
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    When thick plates are connected, it is usual to apply a multi-pass welding process. Although there have been many studies reported on weld cracks in multi-pass welds, it is very difficult to find information concerning detailed mechanical behavior of multi-pass welded joints in the entire course of welding. The main reason can be attributed to difficulties encountered in both theoretical analysis and experimentation.
    Since one of the authors has developed an analytical method of thermal elastic-plastic problems solving based on the finite element method, the difficulties in theoretical analysis were fundamentally resolved and the application of this method has provided useful information on the mechanical behaviors of weld joints of many types.
    In this paper, an investigation was carried out into welding stresses and strains induced in multipass welds in a research model (total 167 passes). The theoretical analysis was performed by the developed method, in which changes in the mechanical properties due to thermal cycles can be accounted with consideration of metallugical changes. An experiment was also conducted to be compared with the theoretical analysis.
    From the results of the investigation, the following important information was obtained.
    (1) The residual stresses predicted by the theoretical analysis coincide well with those obtained by the experiment. This implies that the analytical method applied is reliable even for this kind of very complicated problem, and can be expected to provide information which would not be readily obtained by experiment.
    (2) The highest transient value of σx always appears below the surface of the latest layer, where it is comparatively small.
    (3) In the distribution of residual stress, σx, the location of the highest stress is several layers below the finishing bead in the midsection, and is about 20 mm away from the toe of the bead on the surface.
    (4) Delayed cracking will initiate below the finishing bead and propagate to the surface.
    This new information is very useful to discuss the conventional construction procedure of structures of thick plates, such as pressure vessels, including prevention of weld cracking, meaning of intermediate annealing, etc.
    Download PDF (656K)
  • Effect of aluminum and titanium
    Masahiro Adachi, Makoto Inui
    1975 Volume 44 Issue 6 Pages 475-482
    Published: June 05, 1975
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    A small amount of aluminum and titanium are generally added, so as to avoid the porosity in weld metals and improve their mechanical properties, to the nickel and monel welding electrodes.
    Such addition of aluminum and titanium, however, it may be promoted the possibility of crack occurrence of the weld metals, because the content of silicon in the weld metals shall increase by reducing reaction of the aluminum and titanium to the silicates of coating flux.
    The authors investigated on the effect of aluminum and titanium in nickel and monel welding electrodes on weld crackings of nickel and monel weld metals.
    The results are summerized as follows.
    1) In nickel weld metals, hot crackings are remarkably observed with increasing aluminum and titanium in the welding electrodes.
    This is considered that some low melting substances are formed in austenite grain-boundaries with the reducing reaction of aluminum and titanium to the silicates.
    On the contrary, in monel weld metals such a phenomenon was not observed.
    2) Amount of aluminum and titanium in nickel weld metals was increased with aluminum and titanium contents in the welding electrodes and such elements were considered to be cause of the decrease of oxygen in the weld metals.
    Therefore, micro crackings with decreasing ductilities (refers as micro crackings) in multitude nickel weld metals were remarkably decreased as the increase of aluminum and titanium in the welding electrodes.
    Meanwhile, the effect of aluminum and titanium on micro crackings of monel weld metals was less than it of nickel weld metals.
    The occurrence of micro crackings of monel weld metals, however, was promoted by a small amount of aluminum in the welding electrodes.
    Download PDF (5294K)
  • Taro Hayashi, Masaru Shibata, Koichi Ogawa, Isamu Fukuhara
    1975 Volume 44 Issue 6 Pages 483-491
    Published: June 05, 1975
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Various local exhaust apparatuses are applied to eliminate the welding fume for the purpose of improving the environment in welding shops. Nevertheless, these apparatuses do not always function, but it comes into question that the parts to be welded are hurt in the case of CO2 gas welding method, on account of the reason that inflow streams of hoods disturb the shield gas atmospheres.
    Therefore, the following are tried to solve above mentioned problem; that is, making the hood's opening ring form would be effective to prevent the disturbance of shield gas atmosphere and to raise the inhaling efficiency of hood.
    From the point of view in this experimental study, the sizes of hoods, the distances between base metals and hood's openings and the suction flow rates are varied, and the fundamental characteristics of hoods aie investigeted.
    Now, the results are summarized as follows.
    (1) Generally speaking, enlarging the size of a hood, closing the distance between a base metal and a hood's opening and increasing suction flow rate improve respectively the inhaling efficiency of hood.
    (2) Such defects as the creation of blow-holes and the lowering of penetration efficiency are partly observed in cases of smaller sizes of hoods.
    As the consequence, it is cleared that a ring hood is very effective, but always the most suitable hood should be designed, considering welding methods, welding position and so on.
    Download PDF (7647K)
  • Isao Masumoto, Koreaki Tamaki, Takeshi Kubo, Shun-ichi Shimada, Akira ...
    1975 Volume 44 Issue 6 Pages 492-498
    Published: June 05, 1975
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Nitrogen was intentionally alloyed to the stainless steel weld metals by shielding gas containing nitrogen of MIG welding. Nitrogen contents, mechanical properties and corrosion rate of weld metals were examined and the following results were obtained:
    (1) Nitrogen content of weld metal increased with the increase of nitrogen content of shielding gas. CO2-N2 shielding gas gave the higher nitrogen content into the weld metal than Ar-N2 shielding gas.
    (2) Nitrogen content of weld metal generally decreased with the increase of welding current. On the higher current welding of a nitrogen alloyed stainless steel (0.2%N) by the same electrode wire, however, nitrogen content of weld metal remained unvaried under the increasing nitrogen content of shielding gas.
    (3) Weld metal strength increased lineally with the increase of its nitrogen content, accompanied with a little decrease of ductility at room temperature and 500°C. The same increase of strength was observed at 700°C, but ductility drop was remarkable.
    (4) The general corrosion of weld metal accelerated lineally with the increase of amount of nitride. However, the influence of nitride on the intergranullar corrosion seemed to be not essential.
    Download PDF (523K)
  • Yutaka Kasamatsu, Masayoihi Kono, Masanori Matsuoka
    1975 Volume 44 Issue 6 Pages 499-504
    Published: June 05, 1975
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The relationship between Charpy V-notch impact characteristics and brittle fracture initiation characteristics in Deep Notch Test has been investigated.
    The summary is as follows:
    (1) Brittle fracture initiation temperature [Ti]C=40, when the applied stress becomes equal to the half value of yield strength and the crack length is 80mm, is related to Charpy V-notch 50% crystallinity transition temperature in the equation: [Ti]C=40=0.687α⋅Trs+7.83 √t -54(°K) where α is yield ratio and t is plate thickness.
    The coefficient of correlation between measured values of [Ti]C=40 and estimated ones is 0.92.
    (2) The required vTrs becomes more stringent with increasing strength and thickness when [Ti]c=40 is constant.
    (3) For preventing brittle fracture in the weldment at-15°C, the estimated maximum heat input is 170 KJ/cm for 60 Kg/mm2 class high strength steel, while it is 50 KJ/cm for 80 Kg/mm2 class high strength steel.
    Download PDF (348K)
feedback
Top