THE ROLE OF FRICTION IN TUBULAR CHANNEL ANGULAR PRESSING

Abstract

In this paper, numerical, analytical, and experimental investigations were undertaken in order to clarify the influence of friction in tubular channel angular pressing (TCAP) as a severe plastic deformation technique for producing nanostructured pipes. The effects of different Coulomb friction coefficients of 0, 0.025, 0.05, 0.075, and 0.1 on the deformation behavior and required load were investigated using the finite element method (FEM). The results showed that the friction coefficient in the TCAP has a significant effect on the required load due to the variation in the friction force during the TCAP. A comparison between the FEM and experimental results showed that the Coulomb friction coefficient is approximately 0.055 in the TCAP process when MoS2 was used as a lubricant. The analytical investigation results in the calculation of the equivalent plastic strain were close to those of the FEM when the friction coefficient increased from 0 to 0.1. The die corner gap in shear zone III decreased with the increasing friction coefficient.