Finite element analysis of die offsetin two-turn incremental ECAP

Abstract

Severe plastic deformation (SPD) is the process used to produce ultra fine grain(UFG), metals are characterised by improved mechanical properties which make them suitable for advanced structural applications. Apart from various SPD techniques, two turn incremental equal channel angular pressing (ECAP), S-shape channel discussed in this paper to double the effective strain in a single press. Unfortunately, processed UFG metals are rarely used in industrial applications due to lack of advancement in ECAP technique. Analysis of ECAP technique by changing die geometry and process parameter helps to produce defect free UFG metals. ECAP channel continuously pressed a very long billet in which repetitions accumulate large plastic strain. Two turn ECAP is useful to increase the productivity. However, any changes in channel angle, corner angle as well as offset length are cause for variation in mechanical properties of metals. In order to check the die suitability of two-turn ECAP with variation of effective strain, punch load, a FEA simulation is carried out and the suitable tool geometry and process kinematics are established. Die channel sat two different offset length are used to study the flow behaviour of metal through 900 channel angel. The mode of material flow is the same as in the well established classical L-shape ECAP process following route C pass, while continuous character and improved productivity suggest that new S-shape ECAP process might be suitable for grain refinement of metals on an industrial scale.