A comparative study on iso-speed extrusion and isothermal extrusion of 6061 Al alloy using 3D FEM simulation

In the present work, computer simulation was used as an alternative means to investigate the effect of process parameter, namely iso-speed and stepwise ram speed change, on extrusion pressure, the thermal response of the workpiece and the stress state of a round bar being pushed through the die. Simulation results show that the stepwise ram speed decrease enables the temperature of the extrudate to reach a steady value, which corresponds to a nearly constant exit temperature, while with an unvaried ram speed the temperature increases monotonically. Such a stepwise ram speed change can increase the productivity by increasing the average ram speed. Furthermore, extrusion pressure is also reduced when the ram speed is lowered in a stepwise manner. This reduces the tensile stresses acting on the extrudate, thus making it less vulnerable to tearing. The results obtained from the simulations show the benefits by changing the conventional iso-speed extrusion mode.