Influence of nanofluid application on wheel wear, coefficient of friction and redeposition phenomenon in surface grinding of Ti-6Al-4V

Abstract

Difficulties in the grinding of Ti-6Al-4V originate from the three basic properties: poor thermal conductivity, high chemical reactivity and low volume specific heat of the material. Under severe grinding conditions, all these factors together lead to the accelerated wheel loading and redeposition of chips over the work surface. Redeposition and wheel loading have a significant effect on the surface finish, grinding forces, power consumption and wheel life. In this study, water-based Al2O3 nanofluid as metalworking fluid is applied during the surface grinding of Ti-6Al-4V under minimum quantity lubrication mode after dressing the wheel with different dressing overlap ratios. The severity of the redeposition over the work surface was observed by measuring various surface profiles taken perpendicular to the grinding direction at several locations on the ground surface. The nanofluid application was able to prevent redeposition over work surface that became evident from the measured surface finish parameters that results along the grinding direction. Coefficient of friction was estimated On-Machine using the measured forces for different wheel work speed ratios, depth of cut and dressing overlap ratios. The results showed the effectiveness of nanofluid in reducing friction at high material removal rate (i.e. high depth of cut and high speed ratio) conditions when compared to the dry environment. From the measured forces variation with respect to the number of passes, it became evident that, nanofluid application delayed the frequency of wheel loading and grit fracturing cycle, which leads to the increase in the wheel life.