Chip segmentation behaviour and surface topography in high-speed turning of titanium alloy (Ti-6Al-4V) with eco-friendly water vapour

In this paper, a new eco-friendly approach of use of water vapour cooling is presented to machine titanium alloy (Ti-6Al-4V) at higher cutting speed. A plain turning operation was carried out for three different cutting speeds (60, 120, 180 m/min) and feedrates (0.08, 0.16, 0.32 mm/rev) with constant depth of cut. The machining performance is evaluated in terms of chip thickness ratio, chip segmentation frequency, surface roughness and surface damage. The experimental study revealed that at higher cutting speed the chips become more ductile and show continuous morphology with serrated tooth because of increased temperature of shear zone and concentrated shear in the deformation zone. It is observed that chip thickness ratio and cross sectional area of the chip is increased with an increase in feedrate for all cutting speeds. The surface finish was improved when snarled and ribbon type chips are formed. Pitch of the chip is decreased as the cutting speed increases for all the feedrates. A significant change in surface roughness was found at different feedrates as compared to cutting speed. A variety of surface alterations are found which vary according to machining conditions.

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