Experimental and Numerical Investigation of the Frictional Forces in Equal Channel Angular Pressing

Abstract

The main limitation of the Equal Channel Angular Pressing (ECAP) is the very high required punching force for pushing the metallic sample to next channel. Frictional forces in ECAP process are responsible for very high required punching force. The participation of exit and entrance channels in total friction force has not been studied experimentally hitherto. Through the current study, two ECAP dies (1) with two channels (normal ECAP die) and (2) with only one channel (the exit channel was missed) were manufactured. Three-dimensional finite element analysis was conducted. The effect of the exit channel on the total punching force, sample geometry, and grain refinement rate were investigated experimentally and numerically. According to the results, the exit channel has a considerable effect on the amount of minimum required punching force and the grain refinement in ECAP process. The comparisons showed that, the trend of the results from experimental investigations were in good agreement with numerical analysis.

A novel equal channel angular pressing design to eliminate punch deflection and to reduce the pressing force

“…Friction on the channel walls creates resistance against metal flow and increases the inhomogeneity of the strain [14]. Friction also increases the required energy and carbon dioxide emission by increasing the required pressing force [15]. Ultrasonic assisted equal channel angular pressing is one of the practical approaches to reduce the pressing force in equal channel angular pressing process [16,17].…”