Machinability of Waspaloy: an investigation of cutting forces and tool wear in turning

The machinability of Waspaloy, a nickel-based superalloy widely used in aerospace applications due to its excellent mechanical and thermal properties, presents significant challenges during machining processes. This study experimentally investigates the influence of two heat treatment conditions (solution annealing and age hardening) as well as the effect of coolant pressure (conventional and high-pressure cooling) on cutting forces, tool wear, and chip morphology during the turning of Waspaloy. Quantitative and qualitative analyses were performed on tool wear types including rake face, flank, and notch wear, while chip morphology was also evaluated to gain deeper insight into the machinability behavior. The results show that high pressure cooling (HPC) improves machinability by reducing cutting forces and minimizing wear, particularly in solution-annealed, large grain samples. In contrast, age-hardened specimens with conventional cooling exhibited the highest wear and cutting forces due to increased hardness and insufficient thermal dissipation. Overall, the findings highlight that both coolant pressure and heat treatment significantly influence the wear mechanisms and cutting performance, with HPC and lower hardness conditions enhancing the machinability of Waspaloy. This work uniquely combines the effects of dual heat treatments and cooling pressures to comprehensively evaluate their combined impact on Waspaloy machinability, providing new insights into optimizing cutting performance and tool life for this challenging superalloy.