Effect of friction model in numerical analysis of equal channel angular pressing process

During the last decade or so there has been a tremendous growth in the research and development of equal channel angular pressing (ECAP) process which was originally proposed by Segal et al. Numerical analyses are being used extensively to evaluate the effect of various die design and process parameters in ECAP. Friction is one such important parameter. Coulomb and shear friction models have been used in the numerical analysis of ECAP process and contradicting results have been reported. This study evaluates the effect of coulomb and shear friction models on the deformation pattern, strain distribution and load requirement during ECAP process and suggests which friction model should be used in the numerical analysis of ECAP process.