Effects of minimum quantity lubrication with water-based nanofluid on machinability of hardened steels

Abstract

Machining of hardened steels at room temperature has always been a challenge due to the generation of excessive cutting force which eventually results in increase in tool wear that makes the machined surface rough. To address the associated problems arises in the hard turning operations, proper implementation of cutting fluid can be a viable solution. In the present decade, CNT water based nanofluid have become a promising new solution in high production machining because of its good fluidity and high thermal conductivity. In this research work the performance of nanofluid using 0.3% volume of Single Walled Carbon Nano Tubes and 0.6% volume of Sodium DodecylSulphate added as surfactantdeionized water has been evaluated in turning of hardened steels material. Dry hard turning was performed to compare the performance the of the nano-cutting fluid. The effects of the nano-cutting fluid on the response parameters (surface roughness, cutting temperature, cutting force, chip reduction coefficient and tool wear) were evaluated based on the significant input parameters (cutting speed, feed rate, depth of cut and material hardness). From the experiment result, it is evident that the developed nano-cutting fluid significantly reduces the cutting force and surface roughness by maximum of 18% and 23% respectively. Moreover, the effectiveness of the nano-cutting fluid in the hard turning process remains effective along with the increase in material hardness. Thus, CNT-water based nano-cutting fluid performed better than the dry machining in turning hardened steels. Finally, both ANN and RSM models were developed for prediction of cutting force and surface roughness as a function of cutting parameters. The models were proved to be successful in terms of agreement with experimental results and can be used in cutting process for efficient and economic production by forecasting the cutting force and surface roughness in hard turning operations.