Chip morphology assessment in turning of hardened AISI 52100 steel under ZnO nanofluid environment

The chip morphology in hard turning significantly impacts tool performance influenced by factors like strain softening, machining parameters, workpiece hardness, and tool geometry. In this current study, AISI 52100 steel of hardness (∼ 55 HRC) has been taken into consideration for the hard turning experiment and a detailed chip morphology study was conducted under ZnO nanofluid MQL (Minimum quantity lubrication) condition assisted by dual nozzle set up. The influence of machining parameters such as cutting speed, feed, depth of cut, and MQL flow rate on different chip morphology criteria like chip reduction coefficient, chip curl angle, chip pitch length, chip pattern, and colour has been studied thoroughly in this investigation. From the experimental study, it was observed that CRC is influenced by the depth of cut while chip curl angle and chip pitch length are majorly influenced by feed followed by cutting speed. Helical, wavy, and spiral shape chips followed by saw-tooth formation chips were observed in the entire investigation. However, spiral chips and blue colour chips were noticed at higher feed and higher cutting speed conditions respectively.