Study on cutting force under serrated chip formation and adiabaitic shear instability during high speed turning of AISI 1045 hardened steel

The metallurgical observation and measurement analysis of the chip morphology and cutting force in high-speed turning of AISI-1045 hardened steel were performed. The influences of workpiece material hardness, cutting condition, serrated chip morphology and adiabatic shear instability on cutting force were analysed. The investigations indicate that two types of serrated chips with deformed adiabatic shear band and transformed adiabatic shear band form during the experiments. Also the hardness of workpiece material and cutting conditions have great influence on cutting force. When the ribbon chips transform into the serrated chips and the deformed bands develop into the transformed bands, the cutting forces decrease significantly because of the adiabatic shear instability and the dynamic ductile damage fracture occurs in primary shear zone.