Weld pool oscillation during pulsed GTA welding
- Delft Univ. of Technology (Netherlands)
This paper deals with weld pool oscillation during pulsed GTA welding and with the possibility to use this oscillation for in-process control of weld penetration. Welding experiments were carried out under different welding conditions. During welding the weld pool was triggered into oscillation by the normal welding pulses or by extra current pulses. The oscillation frequency was measured both during the pulse time and during the base time by analyzing the arc voltage variation using a Fast Fourier Transformation program. Optimal results are obtained when full penetration occurs during the pulse time and partial penetration during the base time. Under these conditions elliptical overlapping spot welds are formed. In the case of full penetration the weld pool oscillates in a low frequency mode (membrane oscillation), whereas in the case of partial penetration the weld pool oscillates in a high frequency mode (surface oscillation). Deviation from the optimal welding conditions occurs when high frequency oscillation is observed during both pulse time and base time (underpenetration) or when low frequency oscillation is observed during both pulse time and base time (overpenetration). In line with these results a penetration sensing system with feedback control was designed, based on the criterion that optimal weld penetration is achieved when two peaks are observed in the frequency distribution. The feasibility of this sensing system for orbital tube welding was confirmed by the results of experiments carried out under various welding conditions.
- OSTI ID:
- 443008
- Report Number(s):
- CONF-950682-; ISBN 0-87170-567-2; TRN: IM9712%%433
- Resource Relation:
- Conference: 4. international conference on trends in welding research, Gatlinburg, TN (United States), 5-9 Jun 1995; Other Information: PBD: 1996; Related Information: Is Part Of Trends in welding research: Proceedings of the 4. international conference; Smartt, H.B.; Johnson, J.A. [eds.] [Idaho National Engineering Lab., Idaho Falls, ID (United States)]; David, S.A. [ed.] [Oak Ridge National Lab., TN (United States)]; PB: 836 p.
- Country of Publication:
- United States
- Language:
- English
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