Effects of Surface Depression on Pool Convection and Oscillation in GTAW

GTA 용접에서 용융풀의 표면 변형이 유동과 진동에 미치는 영향

  • 고성훈 (한국과학기술원 기계공학과) ;
  • 최상균 (영남대학교 공과대학 기계공학부) ;
  • 유중돈 (한국과학기술원 기계공학과)
  • Published : 1999.12.01

Abstract

Surface depression in the arc welding is calculated numerically to analyze its influence on pool convection and oscillation. The magnitude of surface depression due to arc pressure on the stationary GTA pool surface is relatively small, and fluctuations of the surface and velocity are caused mainly by arc pressure. The inward flow on the surface due to the electromagnetic force and positive surface tension gradient acts to decrease surface depression. Surface depression appears to have minor effects on average flow velocity and thus pool geometry. Pool oscillation occurs due to surface vibration, and oscillation frequencies are affected mainly by the surface tension and pool width. The input parameters such as arc pressure and current have negligible effects on the oscillation frequency, and the surface tension gradient has limited effects. Since the oscillation frequency varies slightly according to penetration, pool oscillation for the partial penetration weld pool is applicable to monitor the pool width.

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