Patent ID: 7150925

Claim:
A coated cutting tool comprising a substrate selected from the group consisting of cemented tungsten carbide and cermet comprising TiCN, (a) a crystal orientation hysteresis layer comprising a carbonitride compound layer comprising aluminum, and (b) a hard coating layer comprising a layer of nitride compound comprising a well-defined crystal orientation, degree of crystallinity, or a combination thereof; wherein (a1) the carbonitride compound layer has an average thickness of 0.05 to 0.5 μm and comprises a Ti—Al carbonitride compound layer expressed by the composition formula (Ti 1−X Al X )(N 1−Y C y ), wherein X ranges from 0.05 to 0.20 and Y ranges from 0.01 to 0.15 by atomic ratio; and (b1) the nitride compound layer has an average thickness of 2 to 15 μm and comprises a Ti—Al nitride compound layer expressed by the composition formula as (Ti 1−Z Al Z )N, wherein Z ranges from 0.45 to 0.65 by atomic ratio; wherein the carbonitride compound layer and the hard coating layer are formed on the surface of the substrate by physical vapor deposition; and wherein the crystal orientation hysteresis layer is deposited between the surface of the substrate and the hard coating layer.