All issues
Volume 49, Issue 1
Displaying 1-9 of 9 articles from this issue
- |<
- <
- 1
- >
- >|
-
J.D. Harrison1980 Volume 49 Issue 1 Pages 6-13
Published: January 05, 1980
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSDownload PDF (533K) -
On the Cosideration of the Noise for the Servo Control System in Directly Arc Observing MethodKatsunori Inoue, Yoshiaki Arata1980 Volume 49 Issue 1 Pages 14-18
Published: January 05, 1980
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThe discussion is made on the noise for the servo control system which is generated when the "Directly Arc Observing Method" is applied to the weld joint tracking.
The structure of the sensor for the weld joint tracking is shown and its performance is explained in the first part.
The result of the experimental measurement of the noise, due to the arc plasma light fluctuation, from the sensor is shown in the next.
Then, the stochastic theory for random process is developed to compare with the experimental result.
The consideration on the noise generation is made on the basis of the theoretical calculation in the last part.View full abstractDownload PDF (323K) -
Yukio Mori, Isao Masumoto1980 Volume 49 Issue 1 Pages 19-23
Published: January 05, 1980
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSA pear-shaped bead crack and the segregations around it were investigated. The best coefficient and limit value to the cracking were also studied.
Main results obtained are as follows.
(a)Pear-shaped bead crack is a solidification crack at last solidification point (L.S.P.), and when restraint stresses work on this, the crack is enlarged reaching the bead surface.
(2)The segregations are recognized in the crack.
(3)As the coefficients of pear-shaped bead crack, there are P/W, (P:bead depth, W:surface bead width), Wm/W(Wm: max. bead width), and A/P, (A:area of weld metal).Among these three, P/W has the best relations to the occurrence of the crack.
(4)When the value of P/W is more than 1.3, the pear-shaped bead crack is liable to occure very often.
(5)The occurrence of the crack depends on the coefficient value of bead shape, P/W or Wm/W.
(6)It is clear that the pear-shaped bead crack is caused by the L.S.P. being enclosed in a bead.View full abstractDownload PDF (4345K) -
Study on Diffusion Welding (Report 8)Osamu Ohashi, Tatsuya Hashimoto1980 Volume 49 Issue 1 Pages 24-29
Published: January 05, 1980
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSRods of pure iron and titanium were welded at cycling temperature containing transformation temperature and constant temperatures which were above and below transformation temperature. The effect of allotropic transformation on the process of diffusion welding has been investigated, compared with isothermal welding.
The following results were obtained.
1.Tensile strength of welded joint is due to welding deformation. As welding deformation is markedly accelerated by repeated transformation during welding compared with isothermal welding, application of transformation to diffusion welding makes welding pressure and time deciease.
2.The shrinkage and decrease of voids along welding interface is accelerated a little by repeated transformation during heating under no load, not due to the acceleration of diffusion, but due to surface roughening.
3.Diffusion coefficient is not enhanced by allotropic transformation.View full abstractDownload PDF (2854K) -
Studies on Electromagentic Welding (Report 1)Isao Masumoto, Koreaki Tamaki, Masatoshi Kojima1980 Volume 49 Issue 1 Pages 29-35
Published: January 05, 1980
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThe electromagnetic force was applied for welding aluminum tubes. The main part of the welding equipment was the condenser of total capacitance of 800μF and the maximum charge voltage of 5 kV. Coils of 10 to 15 turns were attached around the tubes. The test specimens were the couples of aluminum tubes and core bars of similar or dissimilar metals and alloys. Both the tapered and straight cores weree used.
The welded joints were examined by peel test and also by microscopic observation on the cross-section.
Annealed aluminum tubes of 15 mm in diameter and the maximum thickness of 1 mm could be welded with the cores at the minimum current of 60 kA. Both the specimens of tapered and straight cores could be welded. The clearances of 1.0 to 1.5 mm were usually necessary between tube and straight core; no successful results could be obtained without clearance. A taper of about 8 degrees was suitable for the tapered core.
Cores of mild steel, carbon steel, cast iron, copper, titanium, molybdenum as well as aluminum and its alloy could be welded with aluminum tubes. Although intermetallic compound layers were produced at the interface of welded zones as in the case of other welding processes, the thickness of the layers were very small as 2 to 20 μm.
The wavy patterns were observed at the interface of welded zones, which were similar with those observed in explosive welding. And it is considered that such the patterns were produced by the high velocity collision between tube and core.View full abstractDownload PDF (1928K) -
Yoshiaki Arata, Shinichi Murakami, Hisakatsu Nishihara, Toshiaki Moric ...1980 Volume 49 Issue 1 Pages 35-38
Published: January 05, 1980
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSHK-40(0.4C-25Cr-20Ni)centrifugal cast steel pipes have been used for reforming and cracking tubes in the reaction furnace for the petro-chemical industry.
The authors have studied the application of the plasma arc welding to the circumferential joint of those pipes and developed the proper programming as to the start of weld, formation of back bead, crater treatment etc. and previously reported about it.
As these pipes are used in the atomosphere under high pressure and temperature, the properties of the welded joint must show as same excellent heat resistance as base metal.
So the authors investigated properties of welded joint by this plasma arc welding and confirmed that the joint shows more excellent properties than TIG.
This time, this welding method was applied for joining of cracking tubes which were used for producing ethylene.
The joint performance in service is reported in this paper.View full abstractDownload PDF (2797K) -
Investigation on Welding Arc Sound (Report 3)Masami Futamata, Yoshiaki Arata, Hiroshi Maruo, Katsunori Inoue, Tetsu ...1980 Volume 49 Issue 1 Pages 39-45
Published: January 05, 1980
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSInvestigations have been made of the effects of the rectangle, sawtooth, triangle and sine current waveforms on the welding arc sound of TIG arc, that is a stationary arc on the water cooled copper plate, by means of a transistor control type power source.
The experimental results have indicated that the welding arc sound depends on the current wavetorm, repetition frequency fp and amplitude τp. The welding arc sound is composed of a fundamental tone which has a frequency spectrum of fp and its harmonics. An excellent frequency spectrum fig agrees with fp in the triangle and sine wave current, but fox changes to higher harmonic in the rectangle and sawtooth wave current.
The effective sound pressure Pe is shown as a function of fp and τp(Pefpm⋅τpn), and the useful equations which are possible to estimate the noise level have been obtained.View full abstractDownload PDF (1841K) -
Jinkichi Tanaka, Toyofumi Kitada1980 Volume 49 Issue 1 Pages 45-52
Published: January 05, 1980
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSHeel cracking, a kind of cold cracking, is successfully reproduced by non-restraint T-type fillet weld cracking test. This crack is likely to be caused with decreasing vertical plate thickness and increasing heat input. This tendency can not be explained by the conventional concept of restraint cracking dealing with relatively thick plate in one dimensional field, but the generation of rotational deformation on the condition of vertical plate thickness smaller than critical thickness, hcr. " These "results lead to the fact that this tvne of crack is characterized as deformation cracking in corimparison with restraint cracking.
The large sized fillet weld cracking tests are also conducted, and their preheat temperature for avoiding cracks is compared with that of non-restraint T-type cracking test. As the results, using the results of non-restraint T-type cracking test, the diagrams are established for avoiding single fillet weld cracking for given thickness, heat input and cracking index of chemical compositions of steel plate, PN.View full abstractDownload PDF (538K) -
1980 Volume 49 Issue 1 Pages 54-82
Published: January 05, 1980
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSDownload PDF (2167K)
- |<
- <
- 1
- >
- >|