Numerical Modeling of Keyhole Dynamics in Laser Welding
Mathematical models and the associated numerical techniques have been developed to study the following cases: 1) the formation and collapse of a keyhole, 2) the formation of porosity and its control strategies, 3) laser welding with filler metals, and 4) the escape of zinc vapor in laser welding of galvanized steel. The simulation results show that the formation of porosity in the weld is caused by two competing mechanisms: one is the solidification rate of the molten metal and the other is the speed that molten metal backfills the keyhole after laser energy is terminated. The models have demonstrated that porosity can be reduced or eliminated by adding filler metals, controlling laser tailing power, or applying an electromagnetic force during keyhole collapse process. It is found that a uniform composition of weld pool is difficult to achieve by filler metals due to very rapid solidification of the weld pool in laser welding, as compared to that in gas metal arc welding.
W. Zhang et al., "Numerical Modeling of Keyhole Dynamics in Laser Welding," Proceedings of SPIE - The International Society for Optical Engineering, SPIE -- The International Society for Optical Engineering, Jan 2002.
The definitive version is available at http://dx.doi.org/10.1117/12.497916
First International Symposium on High-Power laser Macroprocessing
Mechanical and Aerospace Engineering
The Commemorative Association for the Japan World Exp.
United States. Air Force. Office of Scientific Research
The Kao Foundation for Arts and Sciences
The Asahi Glass Foundation
Keywords and Phrases
Formation of Porosity; Keyhole Collapse; Keyhole Formation; Laser Welding; Welding with Filler Metals
Article - Conference proceedings
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