Numerical modeling of the welding phenomenon in forward aluminium extrusion process

There is often need to use welding methods in the aluminium alloys extrusion processes. Welding methods while extruding are divided in to transverse and longitudinal one. In paper the energy criterions for transverse and longitudinal joining during extrusion of aluminium alloys in warm conditions are showed. Numerical simulation results for two cylindrical billets transverse joining, during forward extruding with using the flat punch are presented. Irregularity in the billets material flow and presence of a void are proved. In order to equalization the flowing billets volumes streams, the numerical model for forward extrusion of cylindrical billets, with using the punch with a toe and initially formed upper billet is proposed. The application of this method causes both transverse and longitudinal welding schemes appearing. Combination of two welding schemas gives the product, which has a core made of material from the upper billet and external layers of the lower billet.