Abstract: The temperature distributions on the surface of Si 3N 4 and Ti(CN) ceramic cutting tools for turning different metallic materials were computed and plotted by using computer simulation based on a mathematic model of heat sources. The results showed that the temperature on the rake face of ceramic cutting tools for turning 18 8 stainless steel was much higher than turning 1045 plain carbon steel due to the much lower thermal conductivity of the former, and it was increased