Numerical investigation on fluid transport phenomena in electron beam welding of aluminum alloy: Effect of the focus position and incident beam angle on the molten pool behavior

Abstract

In this study, a three-dimensional model involving heat transfer and melt flow is established to study the influence of the focus position and incident beam angle on the molten pool behavior in electron beam welding of aluminum alloy. The effects of gravity, surface tension and recoil pressure are considered during the simulation process. The formation process of a dynamic keyhole is also investigated. Numerical results indicate that a nail-shaped weld seam with the large aspect ratio is easily formed at the defocus of 0 mm and a wedge-shaped weld seam with the small aspect ratio is easier to appear at the defocus of −8 or +8 mm. The keyhole and molten pool are inclined along the incident direction of the electron beam. Besides, a wider and shallower keyhole could be found with an incident angle of 30° or 150°. The processing parameters at the defocus of 0 mm and with beam inclination angle greater than 90° are helpful to improve the weld quantity. Moreover, the corresponding welding experiments are performed to verify the precision of the numerical models applied in this work. The simulated weld results agree well with the experimental data.