Chip-tool interface access and chip-breakability investigations when turning nitronic 33® steel with conventional and high-pressure coolant supply

Chip control in automated production lines is still poses serious problems when machining ductile metals like most steels. In the past 10 years cutting fluids applied under high-pressure (typically between 3-30 MPa) have been successfully implemented to improve chip breakability and machinability of titanium and nickel-base super-alloys. This study investigates the relationship between coolant pressure employed and plastic deformation in the primary and secondary shear planes as well as its effect on chip-breakability when turning high chromium base, Nitronic 33((R)), steel. Results show that improved coolant access to the cutting interfaces was achieved when turning with 14 MPa coolant pressure. Increase in the coolant pressure enhances chip breakage.