Machinability analysis of nickel-based superalloy Nimonic 90: a comparison between wet and LCO2 as a cryogenic coolant

The usage of cryogenic fluid is increasing in the machining industries especially to cut the materials having a lower machinability like Nimonic 90, a nickel-based alloy. However, the comparison of flood coolant and LCO2 as a cryogenic fluid based on machining performance has not been found for machining Nimonic 90. In this regard, this study compares LCO2 and conventional mineral oil-based flood coolant on the basis of machining performance while turning Nimonic 90. The effect of turning process parameters (cutting speed (v(c)), feed (f), and depth of cut (a(p))) and cutting fluids has been identified by analyzing machinability indicators like cutting force, flank tool wear, power consumption, surface roughness in terms of R-a, and chip morphology. Increment of 34%, 25%, and 24% in cutting forces has been observed for cryogenic turning using LCO2 in comparison with wet machining when the values of a(p) are 0.75, 0.50, and 0.25 mm, respectively. A decrement of 63% tool wear has been seen in LCO2 cryogenic fluid in contrast to wet machining at higher values of v(c), f, and a(p). The superior surface finish has been found in wet machining, while lesser power consumption was recorded for LCO2 as a cutting fluid. Cryogenic machining provided better chip breakability in comparison with wet machining.

Automated summary

This study compares the performance differences between using liquid carbon dioxide and traditional mineral oil-based flood coolant in machining Nimonic 90 alloy, finding that cryogenic turning with liquid carbon dioxide can reduce cutting forces and decrease tool wear compared to wet machining.