High speed milling of INCONEL 718

High speed milling of nickel based supper alloy INCONEL 718 with (Ti, AI)N coated cemented carbide tool was conducted in the cutting speed range 175 similar to 300 m/min. Cutting temperature was also measured by tool-work thermocouple method. The wear rate depended largely on the temperature. There was the threshold cutting temperature about 600 similar to 700 deg. C. Tool wear rapidly grew at the cutting temperature over the threshold whereas gradually grew below the threshold. Long tool life was obtained under the cutting condition that the cutting temperature was controlled below about 600 deg. C. Increase of feed and axial depth of cut in stead of cutting speed or radial depth of cut was recommended in order to achieve the improvement of metal removal rate and acceptable tool life.