The Influence of Cryogenic Coolants in Machining of Ti–6Al–4V

Machining of titanium alloy Ti–6Al–4V is a challenging task because of the greatly increased cutting temperature that results in short tool life. Numerous attempts have been made in the past by employing various cutting fluids for machining purpose, including liquid nitrogen (LN₂) as the cryogenic coolant. This study deals with the influence of cryogenic coolants, especially LN₂ and carbon dioxide (CO₂), in machining of Ti–6Al–4V and its effects on cutting temperature, cutting forces, surface roughness, chip morphology, and tool wear. The results obtained in cryogenic machining are compared with that of dry and wet machining. Cutting temperature was reduced to an extent of 36% and 47% in cryogenic CO₂ machining and cryogenic LN₂ machining in comparison with wet machining. The application of CO₂ produced reduced cutting forces up to 24% and improved surface finish up to 48% compared to cryogenic LN₂ machining. It also produced better chip control and minimized tool wear than dry, wet, and LN₂ machining.