WC-3TiN-0.8Cr3C2-8Co cemented carbides were sintered in de-nitriding and nitriding conditions to use as the cutting tools for HT250 gray cast iron, respectively. Their microstructures and mechanical properties were studied, and the influence of feed rate on tool wear mechanism was investigated. Tool wear mechanism was analyzed by SEM and EDS. Denitriding cemented carbides with the same composition and grain size were prepared for comparison. The results showed that the inserts of nitriding WC-3TiN-0.8Cr3C2-8Co cemented carbides possess higher hardness, and better cutting performance than denitriding inserts under the same cutting condition. There were abrasive wear, oxidative wear and obviously abrasive wear on the flank of nitriding inserts. As for denitriding inserts, there were combination of adhesive wear, oxidative wear, built-upedge (BUE) and abrasive wear on the flank face. Their dominant failure mechanism was abrasive wear. In addition, adhesive wear also played a role in the tools failure to some extent for both nitriding and denitriding cemented carbides cutting tools.

Keywords: Cemented carbide, Nitriding, Wear, Failure mechanism.