Effects of high-pressure cooling on the wear patterns on turning inserts used on alloy IN718

Several emerging technologies are being explored to increase the efficiency of machining nickel based alloys. These include the so-called assisted machining processes. Within that group, use of high-pressure cooling has been increasing since its introduction in the 1950s by Pigott and Colwell. The present study compares changes in tool wear patterns for high-pressure cooling (HPC) with those for flood cooling during rough face-turning of wrought nickel-based alloy IN 718. The alloy was face-turned with uncoated carbide tools at a contact cutting speed of 30 m/min, using conventional and high-pressure coolants (HPCs) at 8 MPa (80 bar). Tool wear and cutting force components were recorded. HPC reduced flank wear more than 30%, and reduced cutting forces by more than 10%. In contrast, notch wear is higher and becomes predominant in HPC. Temperatures during turning were also measured and compared to the results obtained from finite element modeling to better understand differences in the notch formation tendency for HPCs compared with conventional.