Effects of Process Parameters on Hot Extrusion of Hollow Tube

The control of hot extrusion process is a highly complicated task due to high deformation and high billet temperature during the process. A high-quality product can be produced by controlling the process temperature. In this present study, hot extrusion process of hollow tube is modeled by finite element method. Effects of process parameters, initial billet temperature, ram displacements, reduction of area, semi-die angle, and friction coefficients are studied. Finite element results are compared with the experimental results from previous studies. The results reveal that there is a good agreement between simulations and experiments. It is determined that reduction of area and friction coefficient have strong effects on surface temperature and extrusion force. The surface temperature is increased with increasing ram displacement and decreased gradually at the exit of the die due to heat transfer with the environment. Extrusion forces are increased up to friction coefficient of 0.35 for 13 and 25% reduction of areas. However, extrusion forces are not changed significantly after 0.2 coefficient of friction for 37 and 48% reduction of areas.