Effect of Die Radii on Material Waste during Equal Channel Angular Extrusion

The principal objective of the present article is focused on the determination of the effect of angular die radii on the strain intensity, strain unevenness, and material waste for material plastic flow in the Equal Channel Angular Extrusion (ECAE) of metals through the use of a 2D Finite-Element Simulation and a regression analysis technique. This analysis is used to determine the effect of external and internal radii of an angular die and workpiece length on the value of the workpiece truncated “fore part,” which characterizes the workpiece waste. It has been found that the relative radius of the external rounding of the angular die has to be minimized at 0.028, and the internal relative radius of the angular die must be within a range of [0–0.3]. The proposed angular die radii conditions for workpieces with relative length 8.474 have allowed the achievement of high strain intensity [0.79–0.91] together with low strain unevenness [0.35–0.48] and minimal waste of an initial nonstationary workpiece part [0.051–0.055] during one pass of an ECAE. Derived regression models give the background for experimentally determined appropriateness for deformation of longer workpieces during angular extrusion with the objective of reducing deformed material waste.