Effect of cryogenic cooling on spindle power and G-ratio in grinding of hardened bearing steel

Cryogenic coolants like liquid nitrogen (LN2) is being recognized as a promising cutting fluid to meet the requirements of sustainable manufacturing, due to its extraordinary ability to dissipate heat from machining zone temperatures and to offer environmental friendliness. In the present work, an attempt was made to explore the capability of LN2 in surface grinding of hardened AISI 52100 steel using alumina abrasive wheel. Unlike the reported literatures the present work observed and identified few adverse effects of LN2 besides its beneficial effects. A suitable power measurement setup was used to monitor the power consumption under cryogenic machining and simultaneously compared with that under dry and conventional soluble oil medium. Application of LN2, as cooling medium, was found to improve grinding ratio but adversely results into significantly higher power consumption as compared to dry and conventional soluble oil. Dimensional inaccuracy was observed to be higher with LN2. Scanning electron microscope (SEM) images of chip morphology indicated the effective cooling of grinding zone under cryogenic environment compared to other dry and wet environments. (C) 2014 Elsevier Ltd.