AA7075 has many good mechanical properties; however, its bonding strength is poor and is difficult to produce extruded hollow products. Although some researchers proposed different method to study welding strength of Aluminum alloy, related study for high strength Aluminum alloy in hollow extrusion process is not enough. This study use DEFORM 3D finite element analysis software to simulate two different types of hollow extruding die configurations for 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 service lives of these two extrusion die components are studied based on the die stress and die wear information. Some information about the study are as follows: ingot material is AA7075, ingot diameter is 127mm, the extruded tube outside dimension is 54mm × 54mm, thickness is 5mm, extrusion temperature is 480°C, and ramp speed is 0.5mm/s, die material is SKD61 with HRC48. Research results show that the maximum extrusion force for type II is greater than type I. The maximum equivalent die stress occurs in upper die rather than in lower die both for type I and II. However, the predicted die life for type II is greater than type I due to extrusion die design. The welding strength for type II square tube is about 300 MPa on each welding seam.

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