Change in Strain Distribution of Cu–35mass%Zn Alloy by Applying Torsional Moment in Cold Upsetting

Abstract

Influence of torsional moment on strain, hardness and microstructure of Cu–35mass%Zn alloy workpiece was investigated in cold upsetting. The cylindrical workpiece was simultaneously compressed in axial direction with a speed of 0.1mm/s and twisted around the compression axis with a speed of 0.5 rpm. The torsional motion was either one–way with a maximum angle of 180° or cyclic alternating with a maximum amplitude angle of 45°. The Vickers hardness of the workpiece forged with a reduction in height of 60% was improved by approximately 7% and reduced heterogeneity of the distribution by approximately 25% by applying torsional moment. The strain distribution of the forged workpiece calculated by finite element analysis agreed with the hardness distribution of the forged workpiece measured by experiment. The shear texture in the microstructure of the forged workpiece increased approximately 20% by applying torsional moment with torsional angle of higher than 15°.