Numerical Modeling of Extrusion Welding in Magnesium Alloys

摘要

Solid-state welding takes place during the extrusion of hollow shapes and tubes made from selected metals such as aluminum and magnesium and their alloys. DEFORM? is one of the most frequently used FEM software packages to analyze the metal flow in deformation processes. However, it has some limitations while applied to study the extrusion welding. The 2D and 3D versions of DEFORM? cannot determine if extrusion welding takes place in a port-hole die. This limitation is a result of a lack of ability to transfer the localized deformation conditions to a judgment about a good or poor weld. In this work, a new modeling method has been proposed to obtain the localized information at the extrusion welding seam. A so-called pressure plate was virtually inserted in the position of the extrusion welding seam, which plays a role of a sensor and has recorded all the information at the given seam during the entire extrusion process. Analytical methods have been utilized to study the data collected from this sensor to evaluate the probability of the formation of the sound extrusion welding seam. The generated results have been used to verify Plata & Piwnik extrusion welding criterion and can be implemented into existing extrusion models to achieve better prediction of weld integrity.