The Influence of Alloy Characterization Approaches on Extrusion Process FEM Simulation Reliability

FEM codes are now widely used by extruders and die makers for die design and process optimization. Accuracy in the material flow stress characterization is becoming a relevant concern for obtaining reliable simulations. Appropriate mechanical tests are necessary for an accurate characterization of different alloys. The hot torsion test is generally considered the most effective method since it allows the characterization of large strains at high temperatures surpassing the limits of tensile and compression tests. In the paper, the characterization by hot torsion test of four different alloys extracted by different casting batches, namely all belonging to the AA6082 class, is presented. The trials were performed with the testing machine available at the University of Bologna. The results of the tests were used as input for numerical simulations of an extrusion industrial case and compared to experimental data to discuss the effect of flow stress definition on numerical simulation reliability.