The Effect of Copper Microstructure on the Surface Characteristics in Roller Burnishing Process

The microstructure characteristics of the material have a significant effect on the results of plastic deformation processes. In this research, the effect of the coarse and fine-grained microstructure on the microhardness and surface quality in the roller burnishing process has been scrutinized. To facilitate comparison of the results, the input parameters including the size of the workpieces, speed, feed rate, the number of passes, the penetration depth, and burnishing tool were selected the same in all experiments. The results revealed that before the surface devastation, the arithmetic average of surface roughness of the coarse-grained microstructure decreased more than the fine-grained microstructure. Moreover, the penetration depth of the burnishing tool in the coarse-grained microstructure is more than the fine-grained, which indicates its proper ductility. With increasing the number of passes in the roller burnishing process, the surface microhardness of coarse and fine-grained microstructures has gradually increased and in all cases, the microhardness of the fine-grained microstructure is higher than the coarse-grained microstructure. Measurement of sub-surface hardness values shows that the microhardness in coarse-grained microstructure has increased to a greater depth than the fine-grained structure.