Tool wear and machining performance of hardened AISI M2 steel in hard turning has been studied. Ceramic tools were used in the cutting tests without coolants, and the workpiece was heat treated to increase its hardness up to Re 60. Cutting forces, temperature, and tool wear were measured in the experiments and the effects of cutting conditions on these were investigated. Important aspects from the research are summarized as follows:1.Flank wear was the dominant wear mode on the ceramic tool insert in hard turning. In contrast, crater wear was very small due to the ceramics high resistance against chemical reactions at high temperature. A notch was unlikely to be formed in the tool.2.The initial flank wear rate mainly depends on the feed rate. High feed rates cause a high initial flank wear rate.3.Depth of cut was the most important cutting parameter to affect cutting force variation, and the cutting force increased due to tool wear.Presented at the 54th Annual Meeting Las Vegas, Nevada May 23–27, 1999