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

2003 ◽  
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.

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

2005 ◽  
Author(s):  
J. Zhou ◽  
H. L. Tsai ◽  
P. C. Wang
Keyword(s):  
Laser Beam ◽  
Laser Welding ◽  
Weld Pool ◽  
Transport Phenomena ◽  
Pool Shape ◽  
Beam Laser ◽  
Dual Beam ◽  
Laser Keyhole Welding ◽  
Weld Pool Shape ◽  
Welding Technique

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.

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

2010 ◽  
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.

Weld Pool Weld Width Prediction Based on Artificial Neural Network

2013 ◽  
Vol 462-463 ◽  
pp. 171-174
Author(s):  
Xiao Gang Liu ◽  
Le Ting Liu
Keyword(s):  
Neural Network ◽  
Weld Pool ◽  
Bp Neural Network ◽  
Arc Welding ◽  
Welding Process ◽  
Pool Shape ◽  
Weld Width ◽  
Network Method ◽  
Weld Pool Shape

In the COgas shielded arc welding, the weld pool forms is closely related to the quality of welding,but weld pool shape is affected by the welding process parameters. By using BP neural network to predict weld puddle weld width, the results show that the experimental data are very close, thus indicating that prediction of weld width through this network method is very effective.

Weld Pool Shape Variations and Electrode Protection in Double Shielded TIG Welding

2010 ◽  
Vol 97-101 ◽  
pp. 3978-3981 ◽  
Author(s):  
Dong Jie Li ◽  
Shan Ping Lu ◽  
Dian Zhong Li ◽  
Yi Yi Li
Keyword(s):  
Weld Pool ◽  
Marangoni Convection ◽  
Welding Process ◽  
Tig Welding ◽  
Width Ratio ◽  
Mixed Gas ◽  
Pool Shape ◽  
Welding Method ◽  
Weld Depth ◽  
Weld Pool Shape

A new welding method named double shielded TIG welding has been investigated and is described in this paper. It is applicable to the TIG process and can improve the weld depth/width ratio and protect the electrode from oxidation during the welding process. A two pipeline structure is designed in the torch. Pure inert gas passes though the inner pipeline which keeps the arc stable and protects the tungsten electrode. A mixed gas containing an active gas passes through the outer pipeline. The active element which is decomposed from the active gas dissolves in the weld pool so as to change the Marangoni convection from an outward to an inward direction, and, as a result, the weld pool shape becomes deep and narrow. The double shielded TIG welding method increases the weld depth by about 2~3 times over the conventional TIG welding. The effects of the active gas (oxygen) in the outer pipeline on the weld pool shapes are discussed. Heavy oxide layer is considered to weaken the Marangoni convection and changes the weld pool shape.

Effects of phase changes on weld pool shape in laser welding

1997 ◽  
Vol 30 (24) ◽  
pp. 3322-3329 ◽  
Author(s):  
Wisanu Pecharapa ◽  
Aravinda Kar
Keyword(s):  
Laser Welding ◽  
Weld Pool ◽  
Phase Changes ◽  
Pool Shape ◽  
Weld Pool Shape

Keyhole and Weld Pool Dynamics in Dual-Beam Laser Welding

2021 ◽  
pp. 183-201
Author(s):  
Shuili Gong ◽  
Shengyong Pang ◽  
Hong Wang ◽  
Linjie Zhang
Keyword(s):  
Laser Welding ◽  
Weld Pool ◽  
Beam Laser ◽  
Dual Beam

scholarly journals The Investigation of Laser Lap Welding Process on High-Strength Galvanized Steel Sheets

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Shiquan Zhou ◽  
Yi Zhao ◽  
Zhenguo Peng ◽  
Fangjie Ren
Keyword(s):  
Laser Welding ◽  
Welding Process ◽  
High Strength ◽  
Galvanized Steel ◽  
Process Technology ◽  
Surface Appearance ◽  
Beam Laser ◽  
Dual Beam ◽  
Laser Lap Welding ◽  
Lap Welding

The development of automobile steel was analyzed in this paper; it is pointed out that high-strength galvanized steel will be widely used in the car body structure. By analyzing welding problems about the dual phase (DP) series of high-strength galvanized steel, the importance of laser welding was concerned. Finally, laser lap welding process technology of high-strength galvanized steel was studied; the results show that the lap weld with welding process smooth and spatter-free as well as beautiful welding bead surface appearance and good mechanical properties can be made by using the dual-beam laser welding technology and interlayer for welding high-strength galvanized steel.

scholarly journals A Study on the Influences of Welding Position on the Keyhole and Molten Pool Behavior in Laser Welding of a Titanium Alloy

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1082
Author(s):  
Baohua Chang ◽  
Zhang Yuan ◽  
Hao Cheng ◽  
Haigang Li ◽  
Dong Du ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Fluid Flow ◽  
Laser Welding ◽  
Weld Pool ◽  
Heat Input ◽  
Welding Process ◽  
Computational Fluid Mechanics ◽  
Weld Quality ◽  
Laser Weld ◽  
Vertical Up

Various welding positions need be used in laser welding of structures with complex configurations. Therefore, it is necessary to gain knowledge of how the welding positions can influence the keyhole and weld pool behavior in order to better control the laser weld quality. In the present study, a computational fluid mechanics (CFD) model was constructed to simulate the laser-welding process of the titanium alloy Ti6Al4V, with which the keyhole stability and the fluid flow characteristics in weld pool were studied for four welding positions, i.e., flat welding, horizontal welding, vertical-up welding, and vertical-down welding. Results showed that the stability of the keyhole was the best in flat welding, the worst in horizontal welding, and moderate in vertical welding positions. Increasing heat input (the ratio of laser power to welding speed) could increase the keyhole stability. When the small heat input was used, the dimensions and flow patterns of weld pools were similar for different welding positions. When the heat input was increased, the weld pool size was increased, and the fluid flow in the weld pool became turbulent. The influences of gravity became significant when a large heat input was used, especially for laser welding with vertical positions. Too high a heat input in vertical-up laser welding would lead to oscillation and separation of molten metal around the keyhole, and in turn result in burn-through holes in the laser weld. Based on the present study, moderate heat input was suggested in positional laser welding to generate a stable keyhole and, meanwhile, to guarantee good weld quality.

Sign in / Sign up

Export Citation Format

Share Document