Modeling keyhole instability and weld pool dynamics during dual beamlaser welding of Aluminum alloys
Many advances have been made to understand the keyhole and weld pool dynamics in single beam laser welding, however, few studies of the transient keyhole instability and weld pool dynamicsduring dual beam laser weldingare reported. Here we present a theoretical study of three dimensional transient keyhole and weld pool dynamics during tandem dual beam laser welding of Aluminum alloy. Effects ofinterbeam distance, welding speeds on the keyhole and weld pool dynamics are investigated. The mechanisms of the improvement of process stability of dual beam laser welding are also discussed. The theoretical results indicate that under a certain interbeam distance, a common keyhole with a single keyhole aperture and two separate keyhole tipsis produced, and the second tip is deeper due to the preheating effect of the first beam in dual beam laser welding. It is found that the two keyhole tipsusually have violently depth fluctuations and only the depth oscillation of the second keyhole tip is likely to be responsible for the porosity defect in the welds. The frequenciesof the depth oscillations of two keyhole tips are both in the order of several kHz, which arecomparable to that of single beam laser welding.Moreover, similar to single beam laser welding, the keyhole oscillations in dual beam laser welding can also be tamed by increasing the welding speed. Furthermore, the predicated weld pool dynamics of dual beam laser welding are significantly different with that of single beam laser welding, particularly near the top part of weld pool. A less turbulent weld pool dynamics is predicated during dual beam laser welding. However, some similar fluid dynamics of weld pool are found near the rear keyhole wall both in dual beam and single beam laser welding. The theoretical results are also compared with experimental results and a good agreement is achieved.
Dual beam laser welding keyhole instability weld pool dynamics numerical simulation
Shengyong Pang Weidong Chen Dunming Liao Jianxin Zhou
State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science State Key Laboratory of Materials Processing and Die&Mould Technology, Huazhong University of Scienc
国际会议
济南
英文
1-20
2012-08-24（万方平台首次上网日期，不代表论文的发表时间）