Development of novel differential velocity sideway extrusion techniques to fabricate lightweight curved structural components

Abstract

In this paper a new extrusion technology, in which two punches are used, and its application to forming lightweight curved structural profiles, is described. The technology is known as differential velocity sideway extrusion (DVSE) and can include, hot extrusion (DVSE-HE), welding extrusion (DVSE-WE), and co-extrusion (DVSE-CE), which have been widely used for curved thin-walled profiles, tubes, and aluminum/magnesium sandwich hybrid bars. By tailoring extrusion temperature, speed, and speed ratio of the punches, a thin-walled profile (~ 1 mm thickness) with small bending radius (less than its width), has been fabricated using DVSE-HE. Using DVSE-WE, two billets were welded in an extrusion die and extruded into a curved tube, in which the welding interface was eliminated. Utilization of DVSE-CE by inserting a magnesium bar into an aluminum tube to form a billet, co-extrusion enabled an aluminum/magnesium sandwich bar with Al as sleeves, to be obtained. These newly developed DVSE techniques illustrate the potential for forming curved lightweight structural parts using a single operation.