Machinability Analysis of Inconel 718 Superalloy with AlTiN-Coated Carbide Tool Under Different Cutting Environments

Abstract

Inconel 718 superalloy is hard-to-machine materials due to low thermal conductivity, high hardness, and chemical reactiveness with high-temperature tool materials. Despite these negative material characteristics, it is widely used in gas turbine engine manufacturing and aviation, where dimensional accuracy and surface integrity are very important. Finish turning, the last machining process, helps to determine the material's working life and surface quality. Thus, this study focused on improving the Inconel 718 superalloy's machinability performance, and finish turning processes were performed using different cutting environments with AlTiN-coated carbide tool. Using dry, minimum quantity lubrication and vortex tube as cooling methods aim to reduce operating costs and develop environmentally friendly methods that will affect employees and the environment less. The experiments were carried out based on Taguchi L9 experimental design. The effects of cutting conditions and machining parameters on tool wear, cutting zone temperature, cutting forces, and surface roughness were evaluated separately. Then, multiresponse optimization was performed using Grey-Taguchi Relational Analysis for the cutting zone temperature, cutting force, and surface roughness. According to the experimental results, the optimum cutting conditions were established by the MQL cooling method, 70 m/min cutting speed, and 0.05 mm/rev feed rate. Besides, SEM images were taken from the tools to investigate the performance of the cutting tools. SEM and EDS analyses were conducted to identify the variations onto cutting tools due to the tool life tests performed with three cooling methods concerning the optimum cutting parameters.