Effect of Machining Parameters on Surface Integrity in Machining Nimonic C-263 Super Alloy Using Whisker-Reinforced Ceramic Insert

Whisker-reinforced ceramic inserts were used to conduct turning trials on nimonic C-263 super alloy to study the effect of different combinations of cutting parameters on surface integrity (roughness, microhardness, and residual stress) by employing energy dispersive spectroscopy, scanning electron microscopy, x-ray diffraction, and Vicker's microhardness test. Abrasion, adhesion and diffusion were found to be the main tool wear mechanisms in turning nimonic C-263 alloy. Based on characterization of surface roughness, a combination of 190 m/min cutting speed and 0.102 mm/rev feed rate was found to be the critical condition for turning nimonic C-263 alloy. Microhardness varied between 550 and 690 HV at the feed rates of 0.102-0.143 mm/rev for a cutting speed of 250 m/min after 9 min of turning. A tensile residual stress of 725-850 MPa on the machined surface was recorded at the preceding combination of cutting parameters. Cutting speed and cutting time had a dominant effect on the magnitude of the residual stress. No evidence of thermal relaxation and reduction in the degree of work hardening was noted during machining at high cutting speed.