Control of aluminium laser welding conditions with the help of numerical modelling

Numerical modelling of laser welding in both conduction and keyhole modes is studied to highlight the influence of the main welding parameters on assembly performance. Numerical simulation enables the thermal history of assembly weld joints to be described. A hot cracking criterion is proposed. The model predicts that (1) a deviation in the localization of the shielding gas does not affect instability and that (2) fluctuations of the absorbed laser beam power generate cooling speed deviations. The results also demonstrate that laser welding in keyhole mode, when compared to laser welding in conduction mode, is more likely to induce higher cooling speeds, greater risks of hot cracking but better sensitivity to post weld age hardening heat treatment.