Surface integrity of Inconel 718 when finish turning with PVD coated carbide tool under MQL

This paper reports the results of an experimental works to investigate the effect of cutting parameters and machining conditions on surface integrity when finish turning Inconel 718, a highly corrosive resistant, nickel-based super alloy, under three cutting conditions (DRY, MQL 50 mL/h and MQL 100 mL/h). The microstructure analysis using SEM on the machined surface suggests that severe deformation took place, leading to microstructure alteration at sub surface level measuring from a few to several micron in thickness. Work hardening under the machined surface was evident from the micro-hardness measurements where higher hardness reading was measured near the surface. The results of this study show that MQL may possibly improve surface integrity characteristics.