Effects of chamber shapes of porthole die on elastic deformation and extrusion process in condenser tube extrusion

This paper describes a 3D FEM simulation of porthole die extrusion process for producing condenser tubes used for a cooling system of automobiles. In general, condenser tube is mainly manufactured by the conform extrusion method, but this process is less effective as compared with the direct extrusion method in productivity per unit time and in the equipment investment. Therefore, it is essential for the conversion to the direct extrusion with porthole die that can produce condenser tube with competitiveness in costs and qualities compared with the existing conform extrusion. However, an experimental method to quantify the deformation behavior of porthole die for condenser tube extrusion has not been established yet, due to its complicated die assembly and complexity of metal flow. FEM is a good alternative to evaluate the three-dimensional deformation behavior of metals in condenser tube extrusion. Especially, an understanding of metal flow in porthole die extrusion is important, because it provides necessary information in die design for high performance extrusion. This study was designed to evaluate material flow, welding pressure, extrusion load, and the tendency of mandrel deflection that is affected by variation of chamber shape on porthole die. An estimation was carried out using FE analysis in non-steady state. Also, this study examined into the mandrel fracture behavior through investigating elastic deformation of mandrel during the extrusion.