Three-dimensional numerical modeling of continuous extrusion

TLDR: In this paper, a 3D finite element model of the Conform process was used to investigate the internal shearing in the extrusion chamber and to optimize the flow of the material within the chamber and reduce the possible defects in the final product.

Abstract: Summary In this work, FEM modeling of Conform extrusion was studied. The material model was viscoplastic and thermally coupled. The Abaqus/Explicit and Deform-3D codes were used for the simulation. Our results show that there is considerable internal shearing within the extrusion chamber. This is consistent with our earlier findings based on 2D simulation of the Conform process. The results also show that it may be possible to optimize the flow of the material within the chamber and thus reduce the possible defects in the final product. In addition, contact pressure on the tools may be reduced by proper design, which is expected to increase the tool life. Keywords: CONFORM process, finite element analysis 1 Introduction Continuous extrusion (Conform) of aluminum rod has been a commercial process since the late 70s[1-3]. Over the past decade, the Conform process has become established as a viable extrusion method for copper products. This versatile method enables the extrusion of long products such as shapes and profiles in virtually limitless lengths, when using continuously cast feed-rod. Continuous extrusion is particularly beneficial for processing non-ferrous metals such as aluminum and copper, which require breakdown processing of the cast grain structure. A cast or coarse grain structure can be transformed into uniform fine-grained metal (10-20 µm) in a single pass. Copper, in contrast to aluminum, will lead to significantly higher tool contact pressures and process temperatures. Consequently, the tool material requirements for copper are more demanding, which increases the tool costs. It is believed that a better understanding of the processing conditions in Conform extrusion will help in improving the overall cost-efficiency of the process. The Conform process was analyzed theoretically by Green [1] and Etherington [3]. Peng [4] made an investigation into material flow on the process using lead as model material. A 2D finite element model for Conform extrusion of copper was published in 1993 by Reinikainen et al. [5]. The material flow in Conform, however, is not two-dimensional. Recently, Velay [6] and Cho [7] have used full 3D finite element models to investigate Conform extrusion of aluminum.