Three-dimensional (3-D) Temperature Distribution Simulation of Fiber Laser Butt Welding of AISI 304 Stainless Steel

摘要

This paper concerns the three-dimensional (3-D) numerical simulation and experimental investigation of fiber laser butt welding AISI 304 stainless steel. On the basis of the 3-D finite element method (FEM) model the temperature distributions of the weld bead at different times are simulated using a double ellipsoid heat source model. The time-temperature profiles of different points are analysed, showing that the temperature is sharply decreased away from the weld bead centre. To verify the simulation results the corresponding fiber laser welding experiments are carried out. The results show that the cross-section microstructures of welded joint are mainly composed of molten pool, narrow heat affected zone (HAZ) and stainless steel substrate. The wineglass-like molten pool shape shows good agreement with the simulated results. And the finer microstructure in the weld bead is resulted from the rapid cooling rate of laser welding which is confirmed by the FEM calculation. The finer microstructures of columnar and equiaxed dendrites are formed in the peripheral and central region of the molten pool.