Effect of microstructure on mitigating tool wear in diamond turning of nitrided steels

Tools used in diamond turning of steels undergo severe tool wear. In this study, several steels were heat-treated and nitrided to investigate the wear mitigating effect of the microstructure of nitrided steels. The results indicate that the tool wear is mitigated with increase in the chromium content of steel. The results also indicate that chromium carbides are transformed into chromium nitrides by nitriding. Thermodynamic analyses demonstrated that chromium nitrides are stable when in contact with diamond at the cutting temperature. Further, the ratio of iron nitrides to iron increased because the iron levels decreased as the chromium levels increased. Although diamond reacts with iron nitrides, the interaction is considerably weaker than that with iron.