Influence of geometrical parameters on material welding in porthole die extrusion: FE analysis

The importance of aluminum extruded profiles is increasing more and more in many industrial fields. The most complex profiles presenting hollow section are cbtained using porthole die configurations. One of the most important phenomena taking place within this configuration is the material solid state welding that occurs when the flows reach the "welding chamber", located before the extrusion hole. The present paper describes the implementation of the welding critsrion proposed by Piwnik and Plata in DEFORM 2D environment. The innovative aspect of this research is that it is possible to actually weld the material considering what happens to the billet material itself. This procedure was used to evaluate the influence of die geometrical parameters on the welding formation. A simplified 2D extrusion model was used to reduce calculation time and to focus the attention just on what happens in the welding region. The results show that the implemented procedure is capable to monitor the weld...