Effect of high-pressure cooling on life of SiAlON tools in machining of Inconel 718

Abstract

High-pressure cooling has proven to be very effective when machining with carbide inserts. Longer tool life and improved chip breaking are among the most commonly mentioned advantages. Nevertheless, this cooling method has been reported to reduce thelife of ceramic tools in machining of heat-resistant alloys. The main reason for that is said to be the accelerated notch wear. Therefore, in this study, SiAlON ceramic inserts with improved resistance to notching were tested in machining of Inconel 718 under highpressure cooling. The results were compared to conventional cooling. It turned out that, while notch wear was still slightly increased when high-pressure cooling was applied, it was no longer critical for the tool life. Flank wear, on the other hand, was reduced, which led to significantly longer tool life. The variation of the tool life appeared to be slightly less and chip breaking was considerably improved. This shows that, when used properly, high-pressure cooling can help to increase the productivity in machining of heat-resistant alloys with ceramic tools. © Springer-Verlag London Limited 2010.