Tool Wear under High Speed End Milling of Nickel-Base Superalloy Inconel 718

Abstract

High speed end milling of nickel base supper alloy Inconel 718 with (Ti, Al)N coated cemented carbide tool was conducted in the cutting speed range of 175∼300m/min. Cutting temperature was also measured by tool-work thermocouple method. The temperature increased in power law of cutting speed, feed rate, and radial depth of cut as seen in milling of Ti-6Al-4V alloy. Temperature in milling of Inconel 718 was about 150∼200°C higher than that in milling the titanium alloy. The wear rate depended largely on the temperature, and it had a local maximum value at the temperature of 640°C because of the adhesive wear. The rate increased rapidly when the temperature was over 680°C because of the thermal wear, while the rate was low and stable when the temperature was below about 600°C because of abrasive wear. There were the optimal conditions that achieved both long tool life and the maximum removal volume. The conditions, however, were limited in extremely narrow range of the temperature about 680°C. The wear rate in milling of Inconel 718 was ten times higher than that of Ti-6Al-4V alloy.