Research Studies on Equal Channel Angular Pressing

Abstract

The most popular Severe Plastic Deformation (SPD) process is Equal Channel Angular Pressing (ECAP), is envisaged as the best method for large volume and at low cost for obtaining Ultra-Fine Grain (UFG) in bulk metals, due to its low force requirement and the resulting low tool pressure. High-strength semi-finished products produced from ECAP have a high potential for application for the manufacture of fasteners for aircraft, components of aircraft fuselage, medical devices, sports equipment, and microsystems. newlineIn this thesis, studies on ECAP process have been carried out by the method of experimental analysis and by FEM modelling and simulation. ECAP dies shapes of different angles (intersection angle and outer arc angle) under different process parameters are used for simulation studies. newlineFollowing limitations of conventional ECAP process are remedied in this research work: newline1. Larger time consumption newline2. Labour intensiveness newline3. High production cost newline4. Material wastage newline5. Billet jamming and die failure newlineThe usefulness of Experimental and FEM analysis in developing practical ECAP process with innovative dies is demonstrated. A Multi-turn (Three Turn) ECAP process to increase the process efficiency and for up-scaling the procedure is developed and patented. A smaller grain size and consequently better yield strength, hardness and surface profile are obtained, with the innovative three turn ECAP design. The outcome of research work has certainly provided momentum to commercialization of ECAP process. newline