The effect of cutting speed and feed rate on the surface integrity in dry turning of CoCrMo alloy

CoCrMo alloy is a high-wear resistant and biocompatible material currently utilized in the production of medical implants, which are cast or forged, and then machined to final dimensions. The machining step is usually conducted under conventional lubricating conditions, forcing to costly and time-consuming cleaning steps. On the contrary, to machine under dry lubricating conditions could modify the part surface characteristics, which, in turn, could have remarkable effects on the part functional requirements. The objective of the paper is to investigate the effect of process parameters on the surface integrity of CoCrMo alloy bars subjected to longitudinal turning under dry conditions. The surface integrity was investigated in terms of (i) surface finish; (ii) sub-surface microstructure refinement and micro-hardness; (iii) residual stresses. The presented results show that under certain conditions the part surface integrity is not altered by the dry conditions.