Investigation of cryogenic cooling effect in reaming Ti-6AL-4V alloy

This research article is based mainly on the investigation of the effect of cryogenic machining, while reaming Titanium grade 5 alloy (Ti-6Al-4V) material. Cutting speed (V_c) and feed rate (f) are two input parameters at three different levels for a constant depth of the hole. The output parameters considered by using a cryogenic LN₂ cooling compared to a conventional flood cooling are torque (M_t), thrust force (F_t), cutting temperature (T), quality of the hole (circularity and cylindricity), surface roughness (R_a) and chip morphology. The results show cryogenic liquid nitrogen (LN₂) cooling resulting in 15–31% reduction in the cutting temperature, 23–57% reduction in the thrust force and 14–65% reduction in torque. Higher surface roughness, circularity (Cir) and cylindricity (Cyl) were observed in the cryogenic LN₂ cooling condition. Furthermore, better chip breakability was observed in the cryogenic LN₂ cooling condition. No drastic change in the microstructure was observed in both flood and cryogenic LN₂ cooling. Increase in microhardness by 10–16% and 8–19% in cryogenic LN₂ cooling over flood cooling was observed.