Establishment And Verification Of Heat Source Model Based On The Fluid Behavior Of Keyhole Of Electron Beam Welding

Heat source model is important to the calculation accuracy of instantaneous temperature field and the stress and deformation in the welding process of numerical simulation. Right now, the heat source models of electron beam welding are mostly based on assumptions. It is essential to get a clear understanding of the physical mechanism of electron beam welding in order to improve the accuracy of the simulation of temperature field, stress and deformation. As electron beam penetrating welding has the effect of keyhole, here we build our heat source model by study the formation of physical processes of keyhole to establish the heat source model.Firstly, the physics equations of the process of electron beam longitudinal welding and the boundary conditions were established by analysis of the longitudinal welding physical process of electron beam deep penetration welding. The process of electron beam welding was modeled through the VOF algorithm combined with temperature field and fluid field iterative computation. Secondly, Solid-liquid interface curve was fitted with stable temperature field data. Then, the heat source model of electron beam welding was established according to the energy distribution and the fitting curve using mathematical integration method. Lastly, the coordinates between the established heat source model and the software were combined together using the secondary development method of MARC.Electron beam spot welding of TC4 plate was simulated by fitted heat source model and experimental verification was carried out with the simulation parameters. According to the hot cyclic curve of simulation, the rationality of the electron beam welding simulation can by initially obtained. Then, according to the law of the welding structural deformation, good agreement between simulation and experiment can be seen by analyzing experimental data and the simulation values of thickness axis of the three lines. Verifications from both deformation and the temperature field confirmed that the fitting heat source model was credible.