US Patent 7789598 Surface coated cutting tool

A surface coated cutting tool comprises a substrate and a hard layer formed on the surface of the substrate, and a contact angle of water θ on the rake face of the hard layer is in the range of 30 to 80°. A surface coated cutting tool comprises a substrate and a hard layer formed on the surface of the substrate, and a contact angle of water θR on the rake face of the hard layer and a contact angle of water θF on the flank face of the hard layer have a relation of θR<θF. Thereby, excellent resistance to wear and fracture can be shown, leading to a excellent surface coated cutting tool.