Formation ability welding seams and mechanical properties of high strength alloy AA7075 when extrusion hollow square tube

Porthole die extrusion has a great advantage in the forming of hollow section of aluminum alloy tube. The proposed paper aims at the development of an extruding seam square tube of AA7075 high strength aluminum alloy by simulation and experiment. There are several factors related to extrusion load such as: billet temperature, billet dimensional, flow stress, die cavity and product geometry. The extrusion loads and die stresses for a hot extruding square tube of AA7075 with respect to different product have been investigated. This study used DEFORM 3D software based on finite element analysis to simulate two different types of hollow extruding die configurations in the square tube extrusion process, namely: Type I welding position at the corners of the square tube and Type II on the side faces. The welding strengths of these two kinds of extruded tube are studied by expanding test and tensile test. The die life of these two extrusion die components are studied based on the die stress and die wear information. The results of FE analysis are compared with those experiments.