Performance of PVD hard ceramic coatings on HSS cutting tools during machining of free cutting steels

The effect of a hard ceramic physical vapour deposited coating on high speed steel (HSS) cutting tools on the machining behaviour of free cutting steels has been studied. TiN, TiCN, and CrN coatings were applied to M2 high speed steels and studies were made of MnS layer formation on the rake face of the cutting tool after a continuous short cutting time. The compositions of the deposited layers were assesses by X-ray analyses of coated and uncoated M2 high speed steel tools. MnS layers have been observed to form within certain cutting conditions depending on the type of coating. Such tribiological layers across the tool/chip interface improve machining performance, which has been confirmed by measurements of cutting force.