Tool wear characteristics in rough turning of Inconel 718 with coated carbide tool under conventional and high-pressure coolant supplies

The machining of nickel-based superalloys is often challenging due to their excellent physical properties. High-temperature gradients are generated at the cutting zone, which accelerates the tool wear and impairs its performance. However, introducing high-pressure coolant (HPC) lubrication has been shown to improve both the tool life and surface integrity. In this investigation, attention has been mainly focused on the tool wear characteristics in the rough turning of Inconel 718. The longitudinal turning experiments have been conducted under conventional and HPC lubrication with two cutting speeds. Coated carbide inserts have been analyzed using several techniques including scanning electron microscopy, energy-dispersive X-ray spectroscopy, and 3D scanning. The experimental procedure has embraced the tool life, the tool wear, the generated forces, and the wear mechanisms. The examination of the worn tool surfaces demonstrates that although the depth of cut notching is more pronounced, it is possible to reduce the flank wear by using HPC lubrication. The results also highlight a marginal reduction in cutting and axial forces, a good chip fragmentation, and a significant improvement of the tool life. Furthermore, the investigations show that the wear mechanisms are strongly influenced using HPC under the various investigated cases.