WEAR PERFORMANCE OF CERAMIC CUTTING-TOOL MATERIALS WHEN CUTTING STEEL

Some test cycles have been carried out in continuous cutting conditions, employing cutting parameters (feed, depth of cut and cutting speed) chosen following experimental planes and suitable test fields. The wear tests have been carried out on AISI 1040 steel with cutting speeds from 5m/sec to 11m/sec. The silicon nitride, sintered carbide, cubic boron nitride and alumina reinforced with SiC whiskers inserts, have shown, at each assigned cutting parameter, poor wear resistance when cutting steel. Alumina and alumina in submicron grain, which has been toughened by ZrO2 phase transformation, and the oxide-based alumina, have been the better wear resistance. The mixed based alumina has shown a wear resistance, a little lower than the previous materials. The low chemical stability seems to be the reason for the poor performances of the silicon nitride and the silicon carbide whiskers reinforced alumina inserts. The high wear rate of the sintered carbide and the cubic boron nitride is essentially due to the pull out of the ceramic particles. From the other hand, the chemical stability, together with their good mechanical properties can explain the appreciable results obtained with the other alumina based materials