Modeling the Transport Phenomena in Moving 3-D Dual-Beam Laser Keyhole Welding

In recent years, laser-beam welding using two laser beams, or dual-beam laser welding, has become an emerging welding technique. Previous studies have demonstrated that it can provide benefits over conventional single-beam laser welding, such as increasing keyhole stability, slowing down cooling rate and delaying the humping onset to a higher welding speed. It is reported that the dual beam laser welding can significantly improve weld quality. However, so far the development of the dual-beam laser welding technique has been limited to the trial-and-error procedure. In this study, the objective is to develop mathematical models and the associated numerical techniques to investigate the transport phenomena, such as heat transfer, metal flow, keyhole formation and weld pool shape evolutions during the moving three-dimensional dual-beam laser keyhole welding. Detailed studies have been conducted to determine the effects of key parameters, such as laser-beam configuration on weld pool fluid flow, weld shape, and keyhole dynamics. Some experimentally observed phenomena, such as the changes of the weld pool shape from oval to circle and from circle to oval during the welding process are predicted and can be well explained by the present model.

Download Full-text

Fluid Flow and Weld Pool Dynamics in Dual-Beam Laser Keyhole Welding

Heat Transfer, Volume 1 ◽

10.1115/imece2003-41711 ◽

2003 ◽

Cited By ~ 2

Author(s):

J. Hu ◽

H. L. Tsai

Keyword(s):

Fluid Flow ◽

Laser Welding ◽

Weld Pool ◽

Welding Process ◽

Laser Beams ◽

Pool Shape ◽

Beam Laser ◽

Dual Beam ◽

Oval Shape ◽

Weld Pool Shape

The use of dual or multiple laser beams is necessary for welding thick-section metals, especially for Nd:Yag lasers which are limited to relatively low power as compared to CO2 lasers. It was also reported that the use of dual laser beams for welding can increase keyhole stability leading to a better weld quality. So far, the development of dual-beam laser welding technologies has been in the experimental stage. The objective of this paper is to develop mathematical models and the associated numerical techniques to calculate the transient heat transfer and fluid flow in the weld pool and to study weld pool dynamics during the dual-beam laser welding process. The simulation was conducted for a three-dimensional stationary dual-beam laser welding. A very interesting change of the top-surface view of the weld pool was predicted. During the welding process, the top-view shape of the weld pool changes, starting from an oval-shape with the long-axis connecting the centers of the two laser beams, to a circle, and finally to an oval-shape with the short-axis connecting the centers of the two laser beams. Although a direct comparison with published experimental observation is impossible (due to the lack of detailed experimental data), the predicted weld pool shape is similar to that observed from experiments. The dynamical change of the weld pool shape can be well explained by the predicted fluid flow field.

Download Full-text

Investigation of Fluid Flow and Heat Transfer in 3D Dual-Beam Laser Keyhole Welding

ASME 2010 International Manufacturing Science and Engineering Conference, Volume 2 ◽

10.1115/msec2010-34252 ◽

2010 ◽

Cited By ~ 2

Author(s):

Jun Zhou ◽

Hai-Lung Tsai

Keyword(s):

Heat Transfer ◽

Laser Welding ◽

Welding Process ◽

Solidification Process ◽

Melt Flow ◽

Single Beam ◽

Keyhole Welding ◽

Beam Laser ◽

Dual Beam ◽

Laser Keyhole Welding

Dual-beam laser welding has become an emerging joining technique. Studies have demonstrated that it can provide benefits over conventional single-beam laser welding, such as increasing keyhole stability, slowing down cooling rate and delaying the humping onset to a higher welding speed. It is also reported to be able to improve weld quality significantly. However, due to its complexity the development of this promising technique has been limited to the trial-and-error procedure. In this study, mathematical models are developed to investigate the heat transfer, melt flow, and solidification process in three-dimensional dual-beam laser keyhole welding. Effects of key parameters, such as laser-beam configuration on melt flow, weld shape, and keyhole dynamics are studied. Some experimentally observed phenomena, such as the changes of the weld pool shape from oval to circle and from circle to oval during the welding process are analyzed in current study.

Download Full-text