Exploring Ideal Process Parameters to Enhance the Surface Integrity Using Grey Fuzzy Integrated Technique

Abstract

Inconel 625 belongs to the category of austenitic nickel chromium-based super alloys and is extensively used in sea water applications, including propeller blades in aerospace as well as oil and gas industries. However, the precision machining of Inconel 625 alloy is still a challenge due to high rate of work hardening, which hinders further applications in industries. In this context, this research study was carried out, involving the end milling of Inconel 625 nickel-based alloy, using process parameters, such as cutting speed, feed per tooth, radial depth of cut and radial rake angle. The study explored the ideal process parameters to enhance the surface integrity of machined surface under a dry cutting environment. The grey fuzzy integrated approach followed gave the best experimental performance, using grey relational coefficient and multi-performance criteria index. Combination of cutting and tool geometry parameters at the feed per tooth of 0.1 mm/tooth, cutting speed 90 m/min, radial depth of cut 0.4 mm and radial rake angle of 11° are recommended as part of the result. It minimizes work hardening of the machined surface and could ensure induction of superior surface integrity in the machined surfaces, by inducing compressive residual stress 158 MPa, minimum average roughness 0.906 µm and microhardness 379 HV.