Turning of Inconel 718 using inserts with cooling channels under high pressure jet coolant assistance

A large amount of cutting heat is generated in the turning process of nickel-base superalloy Inconel 718. This research proposed a new concept of inserts with cooling channels to enhance the heat transfer from the tool to coolant by generating turbulent flow in the flank clearance under the condition of high pressure coolant. Through and blind channels were made from the flank face and their influences on the wear and tool life were investigated in the longitudinal turning of Inconel 718. Energy dispersive spectroscopy analysis and computational fluid dynamics analysis were also conducted in addition to the cutting experiments. As a result, inserts with cooling channels decelerated flank wear rate and reduced the adhesion of workpiece material on the flank faces. The extension of tool life brought by the through channel was about twice larger than that done by ordinary tool in the high pressure jet coolant machining. However, the tool life extension advanced by the blind channel was limited to the turning at a small depth-of-cut. Computational fluid dynamics analysis clearly showed the differences in the coolant flow pattern caused by the through and blind channels, and concluded that their cooling abilities depend on the hydraulic pressure value and gradient, respectively.