Rough turning Inconel 750 with supercritical CO2-based minimum quantity lubrication Original Research Article

This paper describes preliminary results of replacing water-based (aqueous) flood coolant with supercritical CO2-based minimum quantity lubrication (scCO2 MQL) in an external turning operation on an Inconel 750 combustor housing. Two series of tests were performed: the first series to compare tool wear performance observed with aqueous flood coolant and scCO2 MQL under identical machining conditions, and the second series to investigate tool wear performance with scCO2 MQL at higher metal removal rates (MRR) than the MRR used in production practice with aqueous flood coolant. All tests were performed using roughing cuts on unaged Inconel with coated carbide tooling, and vegetable oil lubricant. As a key enabler, special flank jet tool holders were used to eliminate chip blockage of the lubricant stream.