• Title/Summary/Keyword: TIG Welding

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The Use of Orbital TIG Welding Process for the Construction and the Repair of Field Piping (자동 오비탈 TIG 용접기술을 이용한 배관 용접)

  • 정인철;심덕남
    • Proceedings of the KWS Conference
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    • pp.27-29
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    • 2004
  • Orbital TIG welding process being used fur the new construction, the repair of nuclear piping system ana other critical piping. When weld quality is important or there are a large number of similar weld to be made or when access is restricted with manual torch, Orbital TIG welding is most effective process because of practical for out-of-position and high weld quality. Furthermore, typically superior to manual TIG welding process where the pipe remains in place and the tungsten electrode orbits the weld. As smaller and more compact welding head is being developed, could operate in tight spaces and lend itself to this type of application better than any other welding process. Orbital TIG welding has become more and more field practical process.

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Pulse TIG welding: Process, Automation and Control

  • Baghel, P.K.;Nagesh, D.S.
    • Journal of Welding and Joining
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    • v.35 no.1
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    • pp.43-48
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    • 2017
  • Pulse TIG (Tungsten Inert Gas) welding is often considered the most difficult of all the welding processes commonly used in industry. Because the welder must maintain a short arc length, great care and skill are required to prevent contact between the electrode and the workpiece. Pulse TIG welding is most commonly used to weld thin sections of stainless steel, non-ferrous metals such as aluminum, magnesium and copper alloys. It is significantly slower than most other welding techniques and comparatively more complex and difficult to master as it requires greater welder dexterity than MIG or stick welding. The problems associated with manual TIG welding includes undercutting, tungsten inclusions, porosity, Heat affected zone cracks and also the adverse effect on health of welding gun operator due to amount of tungsten fumes produced during the welding process. This brings the necessity of automation. Hence, In this paper an attempt has been made to build a customerized setup of Pulse TIG welding based on through review of Pulse TIG welding parameters. The cost associated for making automated TIG is found to be low as compared to SPM (Special Purpose machines) available in the market.

Effect of Be Mixing Ratio on the Characteristics of TIG Welding with High Current and High Speed (대전류 고속 TIG 용접 특성에 미치는 He 혼합비의 영향)

  • Oh Dong-Soo;Kim Yeong-Sik;Cho Sang-Myung
    • Journal of Welding and Joining
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    • v.23 no.3
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    • pp.54-60
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    • 2005
  • Tungsten Inert Gas(TIG) welding is today one of the most popular arc welding process because of its high quality welds and low equipment costs. Even if welding productivity increases with welding speed and current, this strategy is limited by the appearance of defects such as undercut and humping bead due to the depressed molten metal. The purpose of this study investigates the effect of He mixing ratio on the characteristics with high current and speed in TIG welding. The conclusions obtained permit to explain the arc start characteristics quantitatively and the maximum welding speed on stable bead formation with He mixing ratio for high current and speed TIG welding observed in experiments. Also through the relation of the maximum arc pressure and surface depression depth at high current and speed TIG welding, it made clear the mechanism of unstable bead formation.

Evaluation of the Integrity of TIG Welding Using Non-Contact SH-EMAT (비접촉 SH-EMAT을 이용한 TIG용접부 건전성 평가)

  • Park, Tae Sung;Park, Yeong Hwan;Park, Ik Keun
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.25 no.1
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    • pp.48-53
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    • 2016
  • An EMAT can be used to reliably detect defects as it serves as a non-contact transducer with the ability to transmit ultrasonic waves into specimens without couplant. Moreover, an EMAT can easily generate desired waves by altering the design of the coil and magnet. This study proposes an SH-EMAT to evaluate the integrity of the TIG welding part. A stainless steel was welded using the TIG welding method. The welding current was varied to create artificial defects. Both the PA-UT and the RT were applied to verify the defect size. The experimental results generated by using the EMAT were compared with those methods. The amplitude was observed to decrease with an increase in the defect size. These results confirmed that the presence of defects can be reliably detected by attenuation of signal amplitude. The results demonstrated that the proposed method is suitable for evaluating the integrity of TIG welding.

The comparison of weld shrinkage between Electron beam welding and Narrow-gap TIG welding for stainless steel (스테인레스강에 대한 전자빔용접과 협개선TIG 용접수축량 비교)

  • Kim Yong Jae;Jeong Won Hui;Sim Deok Nam;Jeong In Cheol
    • Proceedings of the KWS Conference
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    • v.43
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    • pp.76-78
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    • 2004
  • The phenomenon of weld shrinkage mainly occurs owing to residual stress by heating, which largely effects on welding quality, Actually as the shrinkage rate depends on the weld deposit amount, so it is desired that the sectional area of weld joint shall be reduced. In this respect the Electron beam welding has more profitable position compare to Narrow-gap TIG welding which is even superior to other arc welding processes. In case of thick austenitic stainless steel the shrinkage rate of Electron beam welding has about $10\%$ of Narrow-gap TIG welding's, which means that residual stress is a lot less than that of Narrow-gap TIG welding. And heat input and welded section area also indicate large difference between two processes.

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The Characteristic Investigation on Narrow-gap TIG Weld Joint of Heavy wall Austenitic Stainless Steel Pipe (오스테나이트계 SS 배관의 협개선 TIG 용접부 특성 조사)

  • Shim, Deog-Nam;Jung, In-Cheol
    • Proceedings of the KSME Conference
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    • pp.670-677
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    • 2003
  • Although Gas Tungsten Arc Welding (GTAW or TIG welding) is considered as high quality and precision welding process, it also has demerit of low melting rate. Narrow-gap TIG welding which has narrow joint width reduces the groove volume remarkably, so it could be shorten the welding time and decrease the overall shrinkage in heavy wall pipe welding. Generally Narrow-gap TIG welding is used as orbital welding process, it is important to select the optimum conditions for the automatic control welding This paper looks at the application and metallurgical properties on Narrow-gap TIG welding joint of heavy wall large austenitic stainless steel pipe to determine the deposition efficiency, the resultant shrinkage and fracture toughness. The fracture toughness depends slightly on the welding heat input.

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A Study on Productivity Improvement in Narrow Gap TIG Welding (Narrow Gap 맞대기 TIG 용접에서 생산성 향상을 위한 연구)

  • Jun, Jae-Ho;Kim, Sung-Ryul;Cho, Sang-Myung
    • Journal of Welding and Joining
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    • v.34 no.1
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    • pp.68-74
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    • 2016
  • Adoption of narrow gap welding shall be increased for the butt joint of thick plate, because the deformation and welding cost is reduced by decrease of cross-sectional area. However, sometimes narrow gap causes defects such as lack of fusion since it has small groove angle and narrow groove width. Therefore, GMAW, GTAW and SAW process shall be adopted to narrow gap welding with small bead hight and low deposition rate. In this study, Super-TIG welding using C-type strip was applied to semi-narrow gap butt joint in order to increase the welding productivity. High deposition rate 10kg/hr was obtained by high current 600A without undercut, humping bead and other welding defects. Measuring the mean and standard deviation of the melting depth to evaluate the developed processes, the fusion line type was determined by measuring the difference between maximum and minium melting depth. Furthermore, a model on arch fusion line and linear fusion line was suggested in order to prevent LF on groove wall in narrow gap butt welding.

T-joint Welding Characteristics of Multi-thin Plate Dissimilar Thickness of SS41 of Automobile Battery by using Nd:YAG Laser (Nd:YAG 레이저를 이용한 자동차 배터리용 SS41 다층박판 이종두께 T형상 용접 특성)

  • Yang, Yun-Seok;Hwang, Chan-Youn;Yoo, Young-Tea
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.10
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    • pp.1078-1088
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    • 2012
  • In this paper, we present research experimental results about the different thickness T-joint welding of the high power continuous wave(CW) Nd:YAG laser for the secondary battery of a vehicle. Although the conventional method used for the secondary battery is a argon TIG welding, we utilize a laser welding to improve Tungsten Inert Gas(TIG) welding's weakness. The laser, which has a couple of advantage such as aspect ratio, low Heat Affected Zone(HAZ), good welding quality and fast productivity utilized in this work is a CW Nd:YAG laser. In order to observe laser welding sections, we used a optical microscope. Through the analysis of the metallographic, hardness, aspect ratio, and heat input, we obtained the desired data in condition of 1800 W laser beam power and 1.8 m/min and 2.0 m/min laser beam travel speeds. In order to compare electric resistances of the argon TIG welding and laser welding, we made an actual battery and the electric resistance of the laser welding is reduced by 40~45% comparing with the argon TIG welding.

A study of model for nitrogen permeation in TIG welding of super duplex stainless steel (슈퍼듀플렉스 스테인리스강의 TIG 용접에서 질소 침투 모델에 관한 연구)

  • Lee, Jae-Hyoung;Jung, Byong-Ho;Cho, Sang-Myung;Jun, Jae-Ho
    • Journal of Welding and Joining
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    • v.33 no.3
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    • pp.68-74
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    • 2015
  • Superduplex stainless steels are important materials to the oil and gas industry, especially for off-shore production. TIG welding of super duplex stainless steels to obtain the optimal phase balance between austenite and ferrite is mainly achieved by controlling the cooling rate and the weld chemistry. The latter depends on the filler wire chosen and the shielding gas used. If TIG welding of superduplex stainless steels is performed with argon shielding gas only, then nitrogen gets lost from the weld pool, which can result in a ferrite-rich weld metal, with an inferior corrosion resistance than parent metal. In the present study, nitrogen permeation model from the shield gas which gets into the weld metal in DCEN-TIG welding has suggested. This plasma stream model shows characteristics of permeation of nitrogen ions into the molten metal due to the strong physical effect of plasma stream which formed by the arc pressure rather than the permeation of nitrogen ions caused by electric effect.

Effect of Heat Flux on the Melting Efficiency and Penetration Shape in TIG Welding (TIG 용접에서 열유속이 용융효율과 용입형상에 미치는 영향)

  • Oh, Dong-Soo;Cho, Sang-Myung
    • Journal of Welding and Joining
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    • v.27 no.2
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    • pp.44-50
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    • 2009
  • The characteristics of arc pressure, current density and heat flux distribution are important factors in understanding physical arc phenomena, which will have a marked effect on the penetration, size and shape of a weld in TIG welding. The purpose of this study is to find out the effect of the heat flux on the melting efficiency and penetration shape in TIG welding using the results of the previous investigators. The conclusions obtained permit to draw a proper method which derived the heat flux distributions by arc pressure distribution measurements, but previous researchers calculated heat flux and current distribution with the heat intensity measurements by the calorimetry. Heat flux of Ar gas arc was concentrated at the central part and distributed low from the arc axis to the radial direction, that of He mixing arc was lower than that of Ar gas, and it was wide distributed to radial direction. That showed a similar characteristic with the Nestor's by calorimetry calculated values. Throughout heat flux drawn in this study was discussed melting efficiency and penetration shape on Ar gas and He mixing gas arc.