JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 41, Issue 2
Displaying 1-9 of 9 articles from this issue
  • Hiroshi Ikawa
    1972 Volume 41 Issue 2 Pages 115-126
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Hiroshi Tamura
    1972 Volume 41 Issue 2 Pages 127-147
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
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  • Yoshihiko Mukai
    1972 Volume 41 Issue 2 Pages 147-161
    Published: 1972
    Released on J-STAGE: August 05, 2011
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  • Growth behavior of subgrains and competitive growth of columnar grains in weld metal
    Tomio Senda, Fukuhisa Matsuda, Hiroji Nakagawa, Mitsuaki Kato
    1972 Volume 41 Issue 2 Pages 162-169
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    Investigations were made on the growth behavior of subgrains which had been developed in the weld metal of 99.93%- and 1050-aluminum single crystal sheets. Besides, the mechanism of the competitive growth of the columnar crystals was made clear. Conclusions obtained are as follows:
    1. Subgrains which had been developed in the weld metal of 99.93%- and 1050-aluminum single crystal sheets grew in the direction of ‹100›. This growth driection, however, was shifted a little in the direction of heat flow when the directions of ‹100› and the heat flow differed to some extent. This phenomenon was obviously observed in 99.93%-aluminum which had less amount of solute than 1050-aluminum. 2. Solidification structure in 99.93%-aluminum single crystal sheet is cellular when the direction of ‹100› almost agrees with the direction of the heat flow. On the other hand, when the directions of ‹100› and the heat flow differ to some extent the subgrains branched out in the direction of heat flow and the solidification structure changes to cellular dendrite.
    3. When the direction of ‹100› inclines against the specimen surface the subgrains does not grow parallel to the specimen surface but grow in the direction of this ‹100›.
    4. The competitive growth occurs when two or more crystals, which exist in the base metal side of the fusion boundary, grow in the weld metal. That is, the crystal whose ‹100› direction almost agrees with the direction of the heat flow grows easily, but the crystal whose ‹100› direction does not agree with the direction of the heat flow does not grow so easily as the former crystal and the crystal finally disappears on the way.
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  • Heat Conduction in Laser Heating
    Yoshiaki Arata, Isamu Miyamoto
    1972 Volume 41 Issue 2 Pages 170-180
    Published: 1972
    Released on J-STAGE: August 05, 2011
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    Generalized heat onduction theory for a surface heat source, where the source moved at a constant speed, its intensity distribution was non-uniform and its power waveform was not constant, was developed, and temperature distributions in laser heating were discussed on the basis of this thenrv.
    Conclusions obtained may be summerized as follows:
    (1) Transient temperature distributions which were computed using measured energy distribution and waveform were in good agreement with the results obtained from micro-examinations observing the fusion line and temperature measurements.
    (2) When the actual focused laser beam, having a Gaussian distribution, was approximated by a circular or ideal point sources, the deviation from the actual temperature distribution increased with increasing the traveling velocity of the source.
    (3) In the case of AISI 304 stain ess steel (SUS 27), it was quite well to neglect an effect of the pulsive laser waveform on the tern perature rise except for at location in the vicinity of the surface, and then the ac excited laser beam may be regarded as an equivalent constant power source. However, for metal with high thermal diffusivity such as aluminium, the effect was large even at the bottom surface of the sheet about 0.3 mm in thickness.
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  • On the Impact Strength of Butt Joint (Report 4)
    Ichiro Kawakatsu, Yoshifumi Suezawa
    1972 Volume 41 Issue 2 Pages 181-193
    Published: 1972
    Released on J-STAGE: August 05, 2011
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    This investigation has been conducted to determine the impact strentgh of brazed (or soldered) joint of mild steel. To obtain some experimental data as to the effects of roughness of base metal, specimens of mild steel (SS41, 12×12×28 mm) were prepared according to the design of Fig. 1(a). The two abutt-ing surface of each specimens were identically finished by emery papers (No. 60, 120, 240, 400, 600), or other mechanical process such as milling, grinding, supper finishing and electrolytic polishing. These specimens were then brazed with BAG-8 filler metal using a resistance furnace (35 KW) operated in hydrogen atmosphere, or soldered by Pb-Sn alloy in the small resistance soldering bath (0.3 KW). Each specimens were machined according to the design of Fig. 1(b). The impact test of these specimens were carried out by 30 Kg-m charpy testing machine. The charpy test of these specimens gave the result shown as follows :
    (a) On the brazing by BAg-8
    (1) Impact strength of specimen polished by emery paper No. 120 was excellent, its value being 1.501 KG-m/cm2, and also that of one machined by milling cutter was very high. But impact strength of specimen polished by emery paper No. 600 was poor, its value being about 1.27 KG-m/cm2.
    (2) Impact strength of specimens with narrow joint clearance (t<0.1 mm) were very low, but that of one with wide joint clearance (t=0.4-0.55 mm) were very high.
    (3) All specimens were failured at filler metal zone as shown Photo. 4, 5.
    (b) On the soldering by Pb-Sn Alloy.
    (1) Impact strength of specimens polished by large grain size emery powder (No. 60, 120) showed about 0.3-0.35 Kg-m/cm2, but that of one polished by small grain size emery powder (No. 400, 600) were about 0.45-0.5 Kg-m/cm2.
    (2) Most of specimens were fractured at interface of joint, but a few of them were fractured at filler metal zone as shown Photo. 7.
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  • Yugoro Ishii, Tadao Onzawa, Nobuyoshi Kobayashi, Kenshi Tsukuda
    1972 Volume 41 Issue 2 Pages 194-203
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    The behavior of molten silver brazing filler metal which is rising a vertical capillary space has been investigated by X-ray fluoroscopy. The specimen used in this experiment, is made of a pair of metal plates and a clearance of capillary space is set from 0.05mm to 0.5mm by metal spacer. After heated to a certain temperature in furnace, the molten metal begins to penetrate into capillary space from lower side of specimen which contacts with it. The movement of the molten metal is observed with 16mm cine camera using X-ray image intensifyer. The penetration rate of molten metal and ratio of void in it are examined from these films. The following results are obtained.
    (1) The penetration rates, of molten metals for the specimens of copper are faster than those for mild steel and stainless steel.
    (2) With increasing a clearance of capillary space, the initial penetration rate increases but equilibrium penetration height becomes lower, as shownin Fig.6 and 7.
    (3) In the experiment, varied the kind of silver brazing filler metal, all kinds of molten metals show good penetration for the specimen of copper, while for the specimen of stainless steel two kinds of molten metals, BAg-7 and BAg-1, exhibit well penetration but a molten metal, BAg-3, is unsatisfactry.
    (4) The voids included in capillary space of copper specimen are easy to move, but in the case of mild steel and stainless steel, the voids are hard to move. In general, void tends to increase in the following case of lower heating temperature, narrower clearance and specimen interface roughly scratched by belt sander etc.
    (5) In the experiment using the fluxes of KF-H3BO3-Na2B4O7 systems, with decreasing the viscosity of fluxes, the voids become to decrease considerably.
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  • Isamu Oda, Itsuro Tatsukawa
    1972 Volume 41 Issue 2 Pages 204-214
    Published: 1972
    Released on J-STAGE: August 05, 2011
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    As a basic research of strain characteristics in automatic arc welding process, which is executed in considerably higher arc current and welding speed than those of manual arc welding, the investigation has been experimentally carried out on submerged arc welding of mild steel plate under different heat inputs (Fig.1 and Table 2). Detailed observation covers the welding thermal cycles, the progress of longitudinal and transverse strains in base metal during welding and cooling as well as the distributions of the longitudinal total, elastic and plastic strains, the transverse shrinkage and the angular distortion after welding. Main results obtained are as follows.
    The transient mechanical strains of longitudinal and transverse directions occur respectively in tension and compression conversely to each other during the former stage of welding and, afterward, change into compression and tension according to the thermal expansion and shrinkage of the weld zone, which are inferable from the thermal cycles (Figs.3 and 8).
    From the distributions of longitudinal total strain and transverse shrinkage after welding, it is clear that the welded plate expands longitudinally in its middle and contracts in its outer portions, that is, the half of plate on either side of the weld line deforms into fan-shape, these rotational deformation being re-markable in case of large heat input (Figs.5 and 10). And also, the large heat input reduces the magnitudes of longitudinal plastic shrinkage occurring in the weld zone, extends transversely the region of its occurrence and consequently reduces the inherent shrinkage (Figs.11 and 12). The observed distributions of longi-tudinal residual stress and plastic strain along the transverse center line of welded plate, in case of low heat input, well agree with those theoretically derived (Tables 4 and 5).
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  • Mainly on Effects of Silicon and Phosphorus in Base Metal
    Noboru Kimata, Seiichi Ando
    1972 Volume 41 Issue 2 Pages 215-224
    Published: 1972
    Released on J-STAGE: August 05, 2011
    JOURNAL FREE ACCESS
    To investigate the effect ofsilicon and phosphorus content in base metal on the hot cracking susceptibility of welds, slit type cracking tests and angle expanding type (the modified Murex type) cracking tests were carried out. The materials used here were two series of austenitic manganese steel base metal, one varying in silicon (0.18-1.85%) and the other in phosphorus content (0.035-0.086%), and 16 Mn-16 Cr type electrodes. 17 Cr-7 Ni stainless steel (AISI 301 type) base metal and 16 Mn-16 Cr, 19 Cr-9 Ni and 25 Cr-20 Ni type electrodes were also used for comparative test with austenitic manganese steel base metal which had normal silicon and phosphorus content.
    In the slit type cracking test on Si series base metal, a few micro cracks were observed in weld heat-affected zone (HAZ), but they seldom extended into the weld metal even if 1.86% Si base metal was used, while conspicuous cracks were observed in the HAZ and weld metal when the phosphorus content of base metal exceeded 0.065% as reported previously by the authors.
    In the angle expanding type cracking test, the cracking susceptibility of weld bead increased as increasing the silicon as well as phosphorus content of base metal. It is also substantially affected by the difference of 0.025% in phosphorus content of the electrodes.
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