JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 39, Issue 11
Displaying 1-11 of 11 articles from this issue
  • Sho Yoshida
    1970 Volume 39 Issue 11 Pages 1132-1139
    Published: November 25, 1970
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Download PDF (3942K)
  • (Treaties using Fourier's Series)
    Kohei Ando
    1970 Volume 39 Issue 11 Pages 1140-1153
    Published: November 25, 1970
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Download PDF (805K)
  • Metallurgical Investigation on White Constrituents
    Hiroshi Ikawa, Shigeo Shin, Yoshikuni Nakao, Teruya Yamashita
    1970 Volume 39 Issue 11 Pages 1154-1162
    Published: November 25, 1970
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    In this report, metallurgical consideration was made on white constituents which had been confirmed tobe the main cause of hot crackings in the heat affected zone of Inconel 713C in the previous paper (Part 5).
    An assumption that white constituents in Inconel 713C are crystalized by the eutectic reaction between Ni solid solution and γ' phase was set up on the basis of studies on the white phases (similar to white constituents in Inconel 713C) observed in the other cast Ni-base superalloys.
    To verify the assumption, the formation process of white constituents was investigated and a metallurgical examination of white constituents was done.
    Moreover, the effects of γ' phase forming elements on the formation of white constituents were researched.
    The conclusions obtained in this study are as follows;
    (1) White constituents are crystallize from liquid by the eutectic reaction between Ni solid solution and γ' phase.
    (2) In Inconel 713C, massive white constituents are formed at the nodes of dendrite boundaries and fine white constituents at the grain boundaries.
    These white constituents are different from one another in morphorgy but same crystallographically. (3) The amounts of white constituents increase with an increase in γ' phase forming elements such as Al, Ti and Nb.
    This experimental result supports conclusion (1).
    Download PDF (8944K)
  • A Study on Stress Relief Heat Treatment (Report 8)
    Jinkichi Tanaka, Tadayoshi Obata
    1970 Volume 39 Issue 11 Pages 1163-1170
    Published: November 25, 1970
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Welded part plays an important role in stress relieving heat treatment, because it shows structural changes during S.R. treatment and enhances the decrease in residual stress. In order to make clear the role of welded part in S.R. treatment, stress relaxation test on deposited metal, stress relieving tests of welded joint and H-type restraint specimens were carried out.
    Deposited metal shows greater reduction in stress than base metal. In addition, an abrupt drop in stress at 250°C and thereafter is observed in the heating stage. This phenomenon could be ascribed to the lowering of creep resistance owing to internal strain field induced by decomposition of retained austenite.
    Stress reduction in HL specimen is smaller than that in welded joint specimen. The main reason for this discrepancy is considered to be the difference in restraint condition between two specimens, because the stress reduction rate is found, both theoretically and experimentally, to be dependent upon the restraint condition of specimen, and HL specimen has a restraint condition in which stress reduction rate is minimum.
    In comparison with the results on base metal, welded part indicates a markedly greater reduction in residual stress, especially in the lower temperature region. Whenever the reduction of residual stress due to S.R. treatment in welded structure is considered, therefore, the effect of welded part should be taken into account.
    Download PDF (577K)
  • Penetration Formed by the Fixed TIG Arc in the Metal Specimen
    Toshio Yamamoto, Wataru Shimada
    1970 Volume 39 Issue 11 Pages 1171-1179
    Published: November 25, 1970
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Various penetration shapes formed in the plates of copper, aluminum, mild steel and stainless steel by the fixed TIG arc at reduced argon pressures are discussed in relation to the electrical and thermal characteristics of the arc mentioned in the previous reports, where the arc is formed between the 2% thoriated tungsten cathode of 4 mm in diameter shaped like a pencil form and a directly or indirectly water cooled anode plate under the following conditions.
    Gas Pressure : 18 to 760 mmHg
    Arc Current : 250, 400, 450A
    Arc Length (Distance between Electrodes) : 4, 9, 15, 25 mm
    The facts elucidated are as follows
    (1) At reduced gas pressure, "cathode zone" (a bright spherical zone) is observed at the neighborhood of the cathode. When the cathode zone touches the anode specimen, the contact zone on the anode surface melts rapidly and a large "conduction type penetration" is formed in the specimen. Then the cathode zone is presumed to have a higher energy density compared to the arc column.
    (2) In the specimen of low thermal conductivity, the "peripheral type penetration" is formed due to the convectional flow in the molten pool when the energy density of the arc is considerably high. It happens sometimes that the depth of the conduction type penetration formed at small current is deeper than that of the peripheral type penetration of larger current.
    (3) At higher pressure the molten pool beneath the arc depresses and the "finger type penetration" is formed in this case. For directly water cooled specimen, the shape of the molten pool is conserved down to room temperature and a hollow part is often formed when the arc length is sufficiently long. At the bottom of the hollow part a solid surface is exposed and no solidified layer is observed on it.
    (4) The, penetration in low thermal conducters such as mild steel and stainless steel varies from the "conduction type" to the "peripheral type" and further to the combined type of "peripheral type" and "finger type", with an increase in the energy density and the plasma stream at the specimen surface.
    For high thermal conductors like copper and aluminum, the "conduction type" is easily formed by the thermal conduction mechanism. Although the "finger type" is likely to appear when the arc energy density is considerably high, no "peripheral type" penetration is observed.
    Download PDF (4914K)
  • Crystallographic Anisotropy of Columnar zone in Aluminum Weld Metal
    Tomio Senda, Fukuhisa Matsuda, Mitsuaki Kato, Hiroji Nakagawa
    1970 Volume 39 Issue 11 Pages 1180-1189
    Published: November 25, 1970
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    By x-ray diffraction technique preferred orientation of columnar zone in TIG-arc welded metal has been investigated for commercially pure aluminum (1S and 2S) 1 mm thick sheets. Conclusions obtained are as follows:
    (1) The preferred orientation of the columnar zone in the weld metals which have been welded in the welding speeds of 250 to 1500 mm/min is seen to be [100] fiber texture as in castings.
    (2) The fiber texture is usually formed near the fusion boundary in the weld metal irrespective of the welding speed.
    (3) The direction of the fiber axis follows that of the maximum temperature gradient as far as the latter changes gradually as the growth proceeds inward in like elliptical shaped puddle. This is because of the competitive growth of the columnar crystals which have been originated epitaxially at the fusion boundary and the growth of the stray crystals which have been newly originated inside the weld metal.
    However the direction of the fiber axis can not follow the direction of the maximum temperature gradient when the latter changes abruptly as is seen at the weld center of tear-dropped shaped puddle.
    (4) In elliptical shaped puddle the angle between the direction of the fiber axis and the welding direction changes from nearly 90 degrees at the fusion boundary to 0 at the weld center as the growth proceeds inward.
    On the other hand in tear-dropped shaped puddle the angle is maintained at nearly 90 degrees from the fusion boundary to the weld center.
    (5) The spread of the direction of the fiber axis is expected within 20 to 60 degrees irrespective of the welding speed.
    (6) From metallographic observation regarding the origination of the stray crystal it is recognized that the growing direction of the subgrain in the stray crystal accords with the normal to the weld ripple, while that in columnar crystal for which the new stray crystal has been substituted considerably deviates.
    Download PDF (10342K)
  • Yoshinori Ito, Akio Michishita
    1970 Volume 39 Issue 11 Pages 1190-1196
    Published: November 25, 1970
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Gas pressure welding is a common process used in the field to weld deformed concrete bars. However, when the bar diameter is greater than e.g. 30 mm, oxide inclusions are liable to form on the surface of gas pressure weld. Because of this phenomenon, the ioint reliability is often lowered.
    The authors herein report a newly developed gas pressure welding process where an extremely rich content of acetvlen was is used and a highly reduced flame is produced so that the oxide inclusions decrease.
    Deformed concrete bars of 51 mm diameter were welded by the developed process, and the mechanical properties of the joints were examined. The results showed highly improved reliability of thus welded joints.
    Download PDF (8407K)
  • Cracking properties under pulsating sine and triangular wave load
    Masaki Watanabe, Yoshihiko Mukai, Toshiyuki Shijima, Terumich Kutsuki
    1970 Volume 39 Issue 11 Pages 1197-1208
    Published: November 25, 1970
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The effect of loading speed on resistance to stress corrosion cracking of AISI 304 stainless steel in the boiling solution of 42 percent MgCl2 under pulsating sine and triangular wave load was studied.
    In the range of comparatively lower loading speeds (for example, in the case of the test under pulsating sine wave load, up to 30 c.p.m.), time to failure became longer with the decrease of loading speed, and approached the estimated time to failure calculated according to the static linear damage law, in which the time to failure was given as the accumulation of only static damage. This variation of time to failure was mainly caused by the variation of crack propagation time rather than that of crack initiation time.
    Moreover, static and dynamic damage rates formed in the total damage which gave the time to failure were calculated according to the static linear damage law, and it was shown from this calculation that the static damage rate was decreased and dynamic damage rate was increased with the increase of cyclic speed for pulsating sine wave load test, and the degree of these variations was more remarkable in the lower stress rank.
    On the other hand, in the range of comparatively higher loading speeds (for example, in the case of the test under pulsating sine wave load, over 30 c.p.m.), time to failure which tended to decrease up to 30 c.p.m. began to increase abruptly with the increase of cyclic speed. This phenomenon may be perhaps caused by the corrosion speed being lower than the loading speed, and authors intend to discuss this problem in another report.
    The threshold stress of stress corrosion cracking which is very important from the viewpoint of design was also varied by the change of loading speed, and this variation was larger for the notched test piece (of which stress concentration factor is about 3) than for the flat test piece. The effect of notch on the threshold stress under pulsating load was larger than that under static load, and in this experiment, the most dangerous cyclic speed of pulsating sine wave load was 30 c.p.m.
    Judging from the coincidence of macroview of fractured part, the stress under static load test should beequivalent to the maximum stress under pulsating load test.
    Download PDF (5724K)
  • Kohei Ando, Takio Okuda
    1970 Volume 39 Issue 11 Pages 1209-1221
    Published: November 25, 1970
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Heat conduction in radial direction in spot welding of infinite wide plate is treated neglecting the heat conduction to electrodes.
    Instead of infinite wide plate, an isolated cylinder (Fig. 2) whose radius α is 1/R2 times of the spot radius r0 is considered and the temperature is calculated when heat is generated uniformly in the inner zone of radius r0. See Fig. 3.
    The temperature is calculated by using Bessel function series for two extreme cases of boundary condition at cylinder surface r=a, namely h=0 and h=∞. See eq. (1)
    Fig. 6, 7 show the temperature variation when the dimensions r0, a are 3 mm, 10 mm, k being 0.065 cm2/sec.
    Fig. 11, 12 show the temperature variation of r=0 and r=a for h=∞, 0.
    The time constant of the first term of Bessel function series which express the temperature variation is given as
    τ1=a212k
    where λ1 is equal to 2.41 or 3.83 according as h=∞ or h=0. See eq. (6), Table 1.
    We see the heat does not reach to r=a for t<τ1, when we take R0=r0/a<0.3. Therefore the calculated temperature for the cylinder of radius a gives the real value for the spot welding in infinite wide plate. The calculated result also shows that the temperature at r=a for infinite wide plate is a little lower than the average value of the results obtained for cylinder by h=0 and h=∞
    Download PDF (839K)
  • 1970 Volume 39 Issue 11 Pages 1222-1236
    Published: November 25, 1970
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Download PDF (1120K)
  • 1970 Volume 39 Issue 11 Pages 1243-1265
    Published: November 25, 1970
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Download PDF (21300K)
feedback
Top