Stress analysis of forward aluminium extrusion process using finite element method

摘要

This paper presents the influence of stresses on the nature of the forward extrusion behaviour of aluminium alloy Al-2014, using different die angles (alpha=15 degrees, 30 degrees, 90 degrees), and different die bearing length (4, 6, 10 mm). These stresses became high effect towards the die life. It was observed that the high values were created in the contact area between the die and the extruded material. The results showed that, a small die angles required higher extrusion load with 20% more than that of large die angles. In all used die geometry, the deformation of aluminium billet, which is caused by shearing and compression stresses, occurred in a small sectional area (bearing area). The results also showed that, the values of these stresses can either increase or decrease depending on the die entrance angle and the die bearing length. To avoid the effects of these stresses on die dimensions, the hardness, material selection, and geometry should be well calculated. A correlation between the calculated data and FEA was studied in this research by constructing an axisymmetrical 2D geometric (Al) model of the tooling and billet for analysis purpose. The required data, which include: effective stress, strain, material deformation velocity and die-work piece contact pressure were obtained from the finite element (FE) model.