Wear behavior of some cutting tool materials in hard turning of HSS

This study presents an assessment of the performance of four cutting tool in the machining of medium hardened HSS: polycrystalline c-BN (c-BN+TiN), TiN coated polycrystalline c-BN (c-BN+TiN), ceramic mixed alumina (Al2O3+TiC), and coated tungsten carbide (TiN coated over a multilayer coating (TiC/TiCN/Al2O3)). The Al2O3+TiC and the coated carbide tools can outperform both types of c-BN at high cutting speeds. Raman and SEM mapping revealed an alumina tribo-layer that protects the surface of the Al2O3+TiC cutting tool. The high chemical and thermal stability of Al2O3 tribo-films protects the tool substrate because it prevents the heat generated at the tool/chip interface from entering the tool core.