Performance of supercritical carbon dioxide sprays as coolants and lubricants in representative metalworking operations

► Supercritical CO2 (scCO2) sprays evaluated against conventional metal working fluids (MWFs). ► Heat removal efficacy of scCO2 can be higher than aqueous MWFs. ► Lubrication efficacy of scCO2 can be higher than straight oils or minimum quantity lubrication. ► Increased penetration of MWF into cutting zone key to improved cooling and lubrication. ► scCO2 sprays give high cooling and high lubricity without a trade-off between the two.