Machining performance comparison of Inconel 625 superalloy under sustainable machining environments

Abstract

In this work, the performance of machining Inconel 625 under different sustainable machining conditions was investigated. Dry, minimum quantity lubrication (MQL), nanoMQL and cryogenic cooling techniques were chosen as sustainable cooling methods for this study and the turning experimental runs were performed by varying the cutting speed, feed and depth of cut at different levels to analyze the influence of each parameter along with the cooling environment on the machinability. The performance comparison was performed on the basis of surface roughness, tool flank wear and cutting force. The variation of the responses with respect to process parameters under different cooling environments was compared. The hardness of the workpieces machined under the selected cooling environments was also studied to analyze the influence of the cutting temperature. Cryogenic cooling outperformed the other sustainable cooling methods owing to the high rate of heat dissipation from the machining zone. Adhesion and abrasion were identified as the tool wear mechanisms under all cooling conditions with the help of SEM micrographs and EDS analysis of cutting tool inserts. Chips produced under each environment are also studied to understand the machinability.