Porthole Extrusion Process Design for Magnesium-Alloy Bumper Back Beam by Using FE Analysis and Extrusion Limit Diagram

摘要

In recent years, several studies with focus on developing state-of-the-art manufacturing technologies have been conducted to produce light vehicles by employing parts made of light materials such as aluminum and magnesium. Of such materials, magnesium has been found to pose numerous issues, because it cannot be deformed (plastic deformation) easily at low temperatures. Furthermore, oxidation on the surface of manganese occurs at high temperatures. This study analyzes the extrusion process for manufacturing magnesium bumper back beams used in vehicles, using finite element (FE) analysis. The properties of magnesium were determined through a compression test performed at high temperatures. And the temperature at which oxidation occurs at its surface was evaluated via an extrusion test. FE analysis was used to evaluate the extrusion load and temperature during the extrusion process, according to changes in initial material temperature and ram speed. Extrusion limit diagram of the extrusion process was derived based on the results of the FE analysis. Process conditions required to be established during the extrusion process were determined by using the derived extrusion limit diagram. The conditions were further validated by the extrusion test.