• Title/Summary/Keyword: Welding pressure

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A Study on the Measurement of Constraint Force of STS304 Thin plate Using the Load Cell (로드셀을 이용한 STS304 박판용접부의 구속력 측정에 관한 연구)

  • 고준빈;최원두;이성구;박성두;이영호
    • Journal of Welding and Joining
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    • v.19 no.5
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    • pp.548-554
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    • 2001
  • The restraint force is required an accurate measurement and analysis to protect weldment from residual stress. Also, this residual stress caused by clacks in weldments are often observed in the weldments of large size nozzles or radial tanks after welding. This paper is preformed on the study of evaluation of welding restraint forces using load cell with STS thin plate which are using pressure vessel steel in the industry field. As a result of this study, as the welding currents are higher and the welding speeds are more slowly, the magnitude of restraint force in process of the flat plate welding hows to be more large. Also, the temperature in process of melting is increasingly rising, then the restraint forces exhibit the compressive forces, whereas the restraint forces during cooling represent extensional force.

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A Study on the Bead Stability in High Speed TIG Welding (고속 TIG 용접의 비드 안정성에 관한 연구)

  • 조상명
    • Journal of Advanced Marine Engineering and Technology
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    • v.18 no.3
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    • pp.68-77
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    • 1994
  • TIG welding process is applied for the active metal such as aluminum and titanium, also sometimes for overlay welding of superalloy. However the welding speed to be applied is very low because of the unstable bead formed in the region of high current and high welding speed. The present study was carried out to examine the basic phenomena of high speed TIG melt run welding by the 2% Th - W electrode(dia.3.2mm) of various tip shapes.

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The welding Characteristics of the Insertion Device Vacuum Chamber of PLS Storage Ring (가속기 저장링 삽입장치 진공 챔버의 용접)

  • 최만호;한영진;김창균;정진화;권영각
    • Journal of Welding and Joining
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    • v.17 no.4
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    • pp.32-38
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    • 1999
  • PAL(Pohang Accelerator Laboratory) designed and manufactured a 5m-long straight vacuum chamber to adopt U7 undulator that is the first insertion device. Top and bottom plates of the vacuum chamber were made of Al alloy A5083-H321, and welded together by the GTAW welding. The leak rate is less than 1×{TEX}$10^{-10}${/TEX} torr·ℓ/s with negligible welding deformation. The pressure has been maintained below {TEX}$10^{-10}${/TEX} torr after installation. This paper reports the welding process and the method applied to achieve ultimate vacuum performance and t satisfy integrity of welds.

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Characteristics of Plasma Emission Signals in Fiber Laser Welding of API Steel (II) -The Relationship between Welding Conditions and Emission Signals- (API강재의 파이버레이저 용접시 유기되는 플라즈마의 방사특성 (II) -용접조건과 방사신호의 관련성-)

  • Lee, Chang-Je;Kim, Jong-Do;Kim, Yu-Chan
    • Journal of Welding and Joining
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    • v.30 no.4
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    • pp.24-30
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    • 2012
  • Laser welding by fiber laser accompanied by a lot of spatter and humping bead. This is because the deep and narrow keyhole usually form due to high beam quality. So the weld bead is formed defects, because the plasma jet with a high vapor pressure make the molten pool on keyhole wall scattered. For such a reason, unstable behavior of keyhole is difficult to monitor laser welding by using the laser induced plasma. Mostly, fiber laser welding of thick plates most be influenced by this effect. Therefore, fiber laser welding has been difficult to apply the sole. Thus, laser welding monitoring based on plasma measurements have much difficulty in measurements and analysis of signal. In this study, influence of the plasma emission signal according to welding speed and laser power in fiber laser welding analysed by using RMS and FFT analysis. We can verify that RMS value of the plasma emission signal changes with welding parameters in fiber laser welding, and aspect ratio greater than 1, the peak of FFT frequency had been moved in accordance with welding parameter.