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Volume 34, Issue 10
Displaying 1-9 of 9 articles from this issue
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Kazuo Ikeda1965 Volume 34 Issue 10 Pages 1039-1048
Published: October 25, 1965
Released on J-STAGE: August 05, 2011
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Otomaro Takagi1965 Volume 34 Issue 10 Pages 1049-1056
Published: October 25, 1965
Released on J-STAGE: August 05, 2011
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Tadato Fujimura1965 Volume 34 Issue 10 Pages 1057-1063
Published: October 25, 1965
Released on J-STAGE: August 05, 2011
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Studies of Cooling Processes in the Cases of Welding with Coated Electrode and Submerged Arc WeldingStudies of Cooling Processes in Various Arc Welding (Report 1)Michio Inagaki, Harumasa Nakamura, Akira Okada1965 Volume 34 Issue 10 Pages 1064-1075
Published: October 25, 1965
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSCooling time, which has an immediate connection with root cracking in a high strength steel weld with its strength level of 60 kg/mm2 and below, from 800 to 300°C was measured for various welding conditions in the cases of welding with coated electrodes and submerged are welding, respectively. Experimental formulas for the estimation of the cooling time were obtained and these nomographs were shown.
The main conclusions are summarized as follows:
(1) Dimensions of heat flow in a weld were varied by any particular combination of welding condition, plate thickness and the shape of penetration.
For the cooling process with two-or three-dimensional heat conduction in a weld, a relation between temperature T on a weld and cooling rate (dT/dS) as the temperature T is shown as follows :(dT/ds)T∞(T-T0)n
where T0: initial temperature of plate
n: the exponent which is varied with dimensions of heat flow in a weld
Hence, the dimensions of heat flow was clearly shown as the gradient of a line in a logarithmic groph of (dT/dS) VS. (-T-T0).
(2) In a finite plate, it was able to determine a minimum size of specimen, which is equivalent to an infinite plate for the given weld heat input, according to the temperature range of a weld thermal cycle to be considered. When they consider the cooling process to 500 and 300°C, the Value of T in the following formula should be chosen as, T*≤320 for 500°C and T*≤210 for. 300°C, respectively.
Where T*=0.24ηJl/mc+T0(°C)
η: thermal efficiency of arc, j: heat input (Joule/cm)
l: bead length (cm), m: weight of plate (gr) and
c: specific heat (Cal/gr.°C)
(3) If thickness (t), initial temperature (T0) of plates and weld heat imput (J) are given in the case of single bead-welding, cooling time (s) from 800 to 300°C at manual arc welding and submerged arc welding can be estimated with the following experimental formula or nomographs by the present authors;
S=K·Jn/(40-T0)2{1+2/πtan-1(t-t0/a)}View full abstractDownload PDF (759K) -
Effects of Oxygen Addition to Shielding GasAkira Uchida, Ryoko Sugawara, Tomihiko Teramoto1965 Volume 34 Issue 10 Pages 1076-1083
Published: October 25, 1965
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThe main problems presently arising with regard to MIG spot welding of aluminium alloys are the variation of weld joint strength and the cracking of weld metal. To solve them, some experiments were conducted on the effects of mixing of a little amount of O2 gas in argon shielding gas, with the following results:
1) Depth of penetration and nugget diameter increase considerably by mixing 0.3-2% amount of oxygen in argon which leads to an increase mainly of the penetration into base metal. Conversely, the button diameter was observed to decrease as a result of the mixing.
2) It was noted that O2 gas contents could be increased up to 5.0% from a metallurgical viewpoint, although for practical appearance of weld surface the mixing amount of oxygen should be kept below 0.5%.
3) Tension-shear strength of weld joint was observed to increase in proportion to the increase of nugget diameter, which in turn increases with the content of oxygen.
4) The variation of tension-shear strength could be kept below 40-30% by mixing 0.3-2% amount of oxygen.
5) The tendency was observed that both weld cracking and porosity in weld deposit decrease when a little amount of oxygen is added.
6) It appears that the improvement of arc concentration as well as arc force and agitation phenomena owing to the mixing of oxygen is the influential factor to the sectional shape of penetration.
7) The decrease of cracking can be attributed to the absence of delayed freezing which caused strain concentration.View full abstractDownload PDF (6517K) -
Tatsuya Hashimoto, Kinzi Tanuma1965 Volume 34 Issue 10 Pages 1084-1091
Published: October 25, 1965
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIt is well known that even a-slight fluctuation of the welding current reflects upon the quality of the spot weld.
The fluctuation of the welding current is frequently caused by the fluctuation of the source voltage during the spot welding, so it is most important to keep the source voltage constant to improve the consistency of spot weld.
The purpose of this report is to discass a few problems concerning with the influence of fluctuation of the source voltage during welding on the strength of weld. The following results were obtained.
(1) The influence of the drop of the source voltage on the strength of weld depended upon the material to be welded and the welding conditions, and was more sensitive in aluminum alloy than steel.
(2) The influence of fluctuation of the source voltage in the beginning of welding cycle on the strength of weld was greater than in the rear period in aluminum alloy, but in steel it was reversible.
(3) The strength of weld decreased slowly with the drop of the source voltage in steel, but in aluminum alloy gave the Vee curve property having the minimum strength at critical conditions, and about 10 percentage drop of the source voltage in the beginning of welding cycle produced the worst result in aluminum alloy.
(4) It was found to be wrong to correlate the strength of weld only with the effective current equivalent to modified welding current.View full abstractDownload PDF (2049K) -
Tomozo Miura, Shizuo Saburi1965 Volume 34 Issue 10 Pages 1092-1100
Published: October 25, 1965
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIt is presumed that weld joint properties of quenched and tempered high strength steel of 60 kg/mm2 by electro-gas arc welding seem to present some problems as to the proper result since the process induces enormous heat input of 130, 000 to 300, 000 joule/cm and slow cooling speed.
The tppical seven plates of Japanese manufactured quenched and tempered high strength steel of 60 kg/mm2 and the Arcos Vertomatic-G for electro-gas arc process have been used. The wire was flux cored type. The groove preparations was square groove.
Respectively general technical tests on the weld efficiency and various studies by small size specimen on the heat-affected zone have been made.
The result of the former test was satisfactory. The later test showed following
Decrease the strength and yield ratio in the coarsened zone of the refined zone side. The 2 mmV notched charpy impact energy indicated minimum in the coarsened zone of the weld metal side. And the hardness decreased toward coarsened zone of the refined zone side and refined zone. However there is no difinite relation of maximum and minimum test value on different zone relative to the heat-affected result.
To improve the notch toughness of weld metal, five kinds of wire have been tested, namely Mn-Si-Ni-Cr-Mo type, Mn-Si-3 Ni-Mo type, Mn-Si-Ni-Mo type and Mn-Si-Mo type. There has been slightly effective increase possible by alloy elements however not quite satisfactory. The fusion parts are greatly affected by the base metal. Good results can be achieved on both heataffected zone and weld metal with less heat input and V or Y groove preparations is prooved to be one of the offective design.View full abstractDownload PDF (3420K) -
On Research for the Effect of Heat Input, Shape of Groove and Heat Treatment on Weld JointTakeharu Watanabe1965 Volume 34 Issue 10 Pages 1101-1108
Published: October 25, 1965
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThe use of self-preheating thermit welding for reinforcing bars had been investigated and described by the author in the previous reports.
In order to determine the field-welding condition, in this report, the author applied the method which had been developed in ealier work, and studied the soundness of weld joint in changing heat input, shape of groove and heat treatment.
The results are as follows :
1) The increasing of heat input resulted in some effects on penetration and impact value. However, tensile strength changed slightly with the increasing of heat input.
Conclusively, little effective change resulted in weld joint with going as high as about 60% of heat input.
2) Although the change of cutting methods of reinforcing bars such as saw, gas and shear cutting resulted in shape of groove, the change of them had no effect on joint strength.
Oil, paint and rust produced bad effects on joint strength.
3) Sufficient joint strength was obtained even in as-welded condition, but better results were gained by normalizing in a short time. For example, the number of repeating bending test and the value of V-notch Charpy at 0°C increased about twice as compared with those of as welded.
4) The welding of different sizes of reinforcing bars was possible when the difference in diameter was not more than 6 mm.View full abstractDownload PDF (3779K) -
Arrangement of Spor Welds and Satic StrengthKimio Kimura, Sadasi Nisino1965 Volume 34 Issue 10 Pages 1109-1116
Published: October 25, 1965
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIn the case of aircrafts etc., the use of spot-welded joints in primary structures is restricted. One of the reasons is that the effect of the design factor such as the spacing, number or arrangement of spot welds on the strength of joints has not been clarified. Due to this reason, the effect of the factor on the static strength of the multiple spot-welded Al alloy joints by MIL-Specification which widely used in aircrafts was studied.
As the result of this study, the relationship between the factor and the static strength of joints has been clarified, and a method of determining the strength of multiple spot-welded joints by the simple joints has been obtained.View full abstractDownload PDF (475K)
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