Integrated approach to machinability and optimization of nitronic-50 with uncoated carbides

Abstract

Nitronic-50 has been dry-turned with uncoated carbides at three distinct levels of cutting velocities, feeds and cutting depths following a face-centered central composite design. Responses in the form of tangential cutting force, tool-tip temperature, flank wear, material removal rate and surface roughness have been thoroughly studied. Wear characteristics showed prevalence of attrition, abrasion, micro-pitting, grooving and spalling as the major forms. Simulated wear was studied using Usui's tool wear criteria. Depth of cut and cutting velocity significantly influenced tangential cutting force, tool-tip temperature and MRR, while feed rate was the prime factor affecting surface roughness. Experimental outcomes showed strong agreement with predictive models, bearing low error percentages and high R-squared values validating their reliability. Further process parameters have been optimized using MCDM and hybridized MCDM integrated metaheuristic techniques. Optimization results advocate of 66.8297 m/min as cutting velocity, 0.08 mm/rev as feed and 0.1 mm as cutting depth obtained with TLBO. Least surface roughness was recorded with MOORA-based Taguchi optimized set, consisting of 100 m/min as cutting velocity, 0.08 mm/rev as feed and 0.5 mm as cutting depth, while highest material removal rate was obtained under optimized sets of MOORA or MOORA-based TLBO, both of which consisted of higher levels of parametric settings. The TLBO-optimized conditions offered reductions of up to 51.94 % in tangential cutting force, 66.67 % in tool-tip temperature, and 57.41 % in flank wear as compared to alternative optimal setups. Surface roughness was 19.64 % lower than MOORA optimization, while MRR was marginally lower, indicating productivity-tool wear trade-offs.