At the high cutting speeds typical for machining with ceramics and the concomitant high temperatures generated at the cutting edge and the rake face of the tool, chemical interaction between tool and workpiece material becomes the predominant mode of tool wear. Commercial SiA1ON and YSiA1ON cutting tools are known to be unsuitable for the machining of steel because of the chemical incompatibility of these materials at elevated temperatures. In this work, the flank and crater wear behaviour in turning steel with a number of experimental ceramics, belonging to the Si3N4-SiO2-A1N-A12O3 system, are compared with that of a commercial YSiA1ON cutting tool and the influence of the workpiece composition on the wear behaviour is investigated. The relative tool wear of the different ceramics is compared with the predicted mechanical wear by abrasion, calculated from the mechanical properties of the ceramics, and the predicted chemical wear, estimated from equilibrium solubility calculations of the ceramic in pure iron. The relative crater and flank wear of the different ceramics correlates well with the predicted chemical wear. Those ceramics with a low solubility in pure iron were not sensitive towards crater formation and showed the least flank wear of the investigated ceramics, although the modest mechanical properties of these ceramics makes them more sensitive to abrasion. The relative tool wear during turning is correlated with the reactivity measured in static interaction couples.
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