Analyzing and enhancing the porthole die design for extruding a complicated AA7005 profile

Abstract

Porthole extrusion enables the production of aluminum profiles with intricate cross-sections. It can efficiently shape complex profiles; however, few studies have investigated complex hot extrusions using porthole dies, particularly with 7000-series aluminum alloys. Although 7000-series aluminum alloys are renowned for their superior strength, they have poor extrudability, especially for complex extrusion profiles. Implementing an effective die design is essential for avoiding extrusion defects and maximizing extrusion performance. In this study, a porthole extrusion method for a complex profile was developed for AA7005, a medium-high-strength aluminum alloy. Computer-aided engineering simulations were employed to analyze die strength and forecast the flow of the material. After the first trial with the initial design, the lower die was slightly modified. However, following this minor modification, there were occurrences of material blockages. A major revision of die design was then performed, in which bearing length, die runout, and pocket shape were all adjusted. For validation, extrusion testing was conducted, and the effectiveness of the modifications was determined. Finally, the extrusion processes of the modified and initial die designs were compared, including their metal flow behavior, maximum extrusion forces, and product dimensions. The study highlights a well-rounded methodology that incorporates simulation and empirical results to comprehensively understand the challenges of complicated profile extrusion processes with medium-high-strength aluminum alloy.