Mesh Reconstruction Technology of Welding Process in 3D FEM Simulation of Porthole Extrusion and Its Application

For extrusion of hollow profile with asymmetric cross-section, existing FEM software cannot simulate the influence of divergent and welding on the metal flowing behaviors, because it is inability to deal with meshes separation and penetration during welding. A mesh-reconstruction technology based on the reverse engineering is proposed in this paper, and extrusions of Al-alloy hollow profiles with various cross-sections are simulated. The results show that the mesh-reconstruction technology can solve the problem of simulation termination caused by the meshes separation and penetration during porthole die extrusion. It is effective to analyze the metal flowing behaviors, temperature distribution, hydrostatic stress in weld-chamber, and stress on dies, which provides a practicable way for die structure design and optimization of porthole extrusion as well as quality forecast of extrusion products.