Use of ceramic tools in hard turning of hardened AISI M2 steel

Tool wear and machining performance of hardened AISI MZ steel in hard turni ng has been studied. Ceramic tools were used in the cutting tests without c oolants, and the workpiece was heat treated to increase its hardness up to Rc 60. Cutting forces, temperature, and tool wear were measured in the expe riments and the effects of cutting conditions on these were investigated. I mportant 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 ceramic's high resistance against chemical reactions at high temperature. A notch was unl ikely to be formed in the tool. 2. The initial flank wear rate mainly depends on the feed rate. High feed r ates 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.