Prediction of weld shape for fiber laser keyhole welding based on finite element analysis

It is of great theoretical significance and engineering value to predict the weld shape for selecting welding parameters. A simplified and efficient three-dimensional (3D) heat conduction model was established to predict weld shape in fiber laser keyhole welding. An improved hybrid heat source model was proposed which consisted of a surface heat flux with a Gaussian distribution and a cylindrical heat source with damped peak value through the depth. The simulation results quite coincided with experimental ones, which indicated that the improved hybrid heat model can explain the energy absorption in keyhole more accurately. Both partially and fully penetrated weld shapes and sizes were predicted. The results showed that prediction errors of the sizes of weld cross-sections in partial-penetration welding were less than 8.9 %. While in full-penetrated welds, they were less than 8.8 % except for size of weld waist.