Comparative Analysis of Two Twist-Based SPD Processes: Elliptical Cross-Section Spiral Equal-Channel Extrusion vs. Twist Extrusion

Abstract

The present paper deals with numerical comparison of two twist-based severe plastic deformation processes: (i) the elliptical cross-section spiral equal-channel extrusion (ECSEE) proposed recently as a novel process and (ii) the classical twist extrusion (TE). ECSEE was developed in attempt to process cylindrical work pieces and to generate more uniform strain distribution compared to classical TE. However, the present finite element simulations showed that twist zones used in both methods impose identical stress and strain states. Furthermore, the ability of ECSEE to treat cylindrical billets is achieved at the expense of the possibility to perform multi-pass extrusion through the twist zone and it requires higher loads for the overall process of extrusion.