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Volume 32, Issue 10
Displaying 1-8 of 8 articles from this issue
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Toshio Ohwa1963 Volume 32 Issue 10 Pages 955-967
Published: October 25, 1963
Released on J-STAGE: August 05, 2011
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Masanobu Hamasaki1963 Volume 32 Issue 10 Pages 968-975
Published: October 25, 1963
Released on J-STAGE: August 05, 2011
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Mamoru Nishihara, Syunzi Yamamoto, Syoziro Shibata1963 Volume 32 Issue 10 Pages 976-983
Published: October 25, 1963
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSCommercial pure Titanium can be readily joined by either TIG or MIG inert-gas shield welding process, but occasionally fine blow holes are detected by X-ray examination.
A study was carried out to make clear the effect of welding conditions on the tendency to "blow hole development" in butt joints of 5 mm thick commercial pure Ti plate. As to welding conditions or factors, purity of shielding inert-gas, welding geometry, welding current, welding speed, feeding rate of filler wire and appearance of filler wire were taken into consideration.
It was concluded that ;
1) MIG welding process, being less susceptible to blow hole, is more suitable than TIG welding to obtain more sound welds.
2) Welds made under atmospheres containing nitrogen, oxygen and hydrogen are more susceptible to blow hole than those obtained under pure Argon atmosphere.
3) Cleanliness of the work to be welded and smoothness of filler wire surface are necessary factors to obtain sound welds.
4) To obtain sound welds, suitable ranges of current and speed for welding are necessary.View full abstractDownload PDF (4666K) -
Kohei Ando1963 Volume 32 Issue 10 Pages 984-985
Published: October 25, 1963
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIt is proved that the optimum current or kVA of condenser connected continuously parallel to A.C. welder, which is used intermittently with duty cycle α is equal to time averaged reactive wattless current or kVA of the welder proper, to mimimize the copper loss in the distribution line. In equations (3), (6), which show the result above mentioned, Ic, Io, Iα mean the condenser current, no load magnetizing current, primary compensating arc load current respectively, IW, IWL being components of Iα.View full abstractDownload PDF (124K) -
Kohei Ando1963 Volume 32 Issue 10 Pages 986-988
Published: October 25, 1963
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThermal equivalent current Ie of electric source supplying to n loads is calculated when eacl load current varies in two modes, i.e. the duty cycles for current I1 and I2 are α1, α2 respectively, α1+α2 being equal to unity. Equation (12) shows the result.
The result can be applied to the case of A. C. arc welders, when the power factor improving condensers are connected continuously parallel to the welders. It is shown that the minimum copper loss of the source can be attained when the condenser current is equal to average wattles current of welder proper. Under this condition, Ie is expressed in equ. (21) and we see that the effect of wattless currents IWL of the welders is neglegible when n>10.View full abstractDownload PDF (195K) -
Solidification of Mother DropKeizo Ishizaki1963 Volume 32 Issue 10 Pages 989-995
Published: October 25, 1963
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThe author discussed various phenomena of solidification of a molten metal droplet with a certain contact angle on the solid surface of the same metal. It was concluded as follows.
(1) If the solidifying layer of a droplet is always flat and horizontal, the contact line of the remaining droplet must move inward to maintain the contact angle. If the droplet is very small and spherical, the final solidified body obtained must be a cone of which the base angle φ is calculated to be 70% of the contact angle θ0.
(2) First assumption is satisfied in the case of very rapid solidification of welding spatter, and the fact that the beautiful conical bodies, 'Ishizaki's cones', were obtained experimentally is considered to support the theory.
(3) The base angle of conical spatters obtained with lime type coated electrode was found to be 45 degrees, therfore its contact angle should be 64 degrees.
(4) Staircase-like solidification found on small metal spatter was explained to be the result of oscillation of remaining molten droplet confined at the edge of each solidified layer.
(5) Three types of bead solidification, that is, slipping, confined and overlapping type, were defined.
(6) Under-cut of weld bead is caused by the simillar mechanism to that of the above-mentioned phenomenon.View full abstractDownload PDF (5348K) -
Studies on Electron-Beam Welding, 7Haruyoshi Suzuki, Tatsuya Hashimoto, Fukuhisa Matsuda1963 Volume 32 Issue 10 Pages 996-1005
Published: October 25, 1963
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSFundamental researches and considerations for welding forces and bead formation in electronbeam welding were done to make use of the measured results of actual vertical force in welding.
The conclusions were as follows :
(1) Vertical force in electron-beam welding is generally increased with an increasing of welding current at constant anode voltage and welding speed.
The vertical force in carbon steel plate is about 2 to 3 times greater than that in aluminium at the same weld heat input.
(2) The vertical force is caused by the repulsion of metal vapour in evaporation because the repulsive force by calculation agrees with the measured force. However, forces of collision of electron-beam and repulsion by magnetic phenomenon are negligibly small compared with the repulsive force of evaporation
(3) It seems that maximum temperature in molten metal of carbon steel, aluminium, titanium or zirconium is about 200 to 400°C higher than the melting temperature of each metal.
(4) Forces which push up the molten metal backward in the back of electron-beam consist of the repulsive force of evaporation, capillary action in wedge-shape hole and surface tension in the solidus line of crater.
It seems that drilling action by electron-beam is stopped and held at the constant depth in molten metal when the push-up forces reach the counter-balance to the forces, such as weight of molten metal and repulsive force in crater, which pull down the molten metal to the bottom of the wedge-shape hole.View full abstractDownload PDF (4530K) -
Current Cayacity and ConsumptionAkira Uchida1963 Volume 32 Issue 10 Pages 1006-1017
Published: October 25, 1963
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIn this paper, the author intends to determine the current capacity and consumption of tungsten electrode in TIG arc welding for the purpose of establishing the standard (JIS) of the electrode.
From this work, the following conclusions are obtained :
(1) The current capacity of pure tungsten electrode under DCSP depends on Joule's heat and consequently on the stick-out length of electrode, and is formulated by experiment as Im=220× (α/le×102)3/4, where a is the cross section of electrode in cm2 and le is the stick-out length of. electrode in cm. The current capacity of thoriated tungsten in argon shielded DCSP arc is rather a little less than that of pure tungsten.
(2) The DCRP current capacity has not a definite critical value, but is determined from a practial standpoint.
(3) The failure of electrode due to over current in the AC TIG arc occurs in two ways ; that is, of S.P. type in smaller diameter electrode and of R.P. type in larger diameter electrode. The AC capacity depends largely on the amount of DC component, and their relation is given by Im=Im0/(1-αPd), where Im0 is the maximum allowable current in the case of balanced AC, Pd is the ratio of DC component to effective value of AC component and a is a theoretically given coefficient. The AC capacity of thoriated tungsten is considerably larger than that of pure tungsten.
(4) From careful measurements using water-cooled Cu anode or aluminum plate as a work piece and preventing start spattering, the electrode consumption under DCSP steady arc is found to be a few mg/30 min. and seems to be caused through pure evaporation. The electrode consumption for AC arc under the same condition is 2 to 3 times the value mentioned above.
(5) For, the arc when using steel plate as base electrode, the consumption is nearly 10 times that for DCSP arc with water cooled Cu anode, and especially in the case of the AC arc successive spattering sometimes accompanies.
(6) At the start of DCSP arc, the spattering of electrode is caused when applying nearly maximum allowable current suddenly to pure, tungsten which was once used. Start spattering is not caused by (a) thoriated tungsten (b) pure, virgin tungsten, (c) arc starting with smaller current.
(7) The start spattering is found to occur succeedingly for about 1/4sec. following the arc ignition, and seems to be caused by the cavity formed at the tip of electrode and the thermal shock.View full abstractDownload PDF (4625K)
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