Coated cemented carbide cutting tool member and process for producing the same

摘要

A coated cemented carbide cutting tool member and a process for production thereof are disclosed. The coated cemented carbide cutting tool comprises a substrate and a hard coating layer deposited on said substrate by chemical vapor deposition and/or physical vapor deposition, wherein said hard coating layer has average thickness of 3 to 25 mu m, and comprises (1) at least one Ti compounds layer that is composed of at least one granular layer of TiC, TiN, TiCN, Ti2O3, TiCO, TiNO and TiCNO, whose average thickness is 0.1 to 5 mu m, (2) TiCN layer having longitudinal growth crystal structure whose average thickness is 2 to 15 mu m, and (3) Al2O3 layer whose average thickness is 0.5 to 8 mu m, wherein, said longitudinal TiCN layer has compositional gradient of carbon and nitrogen along with its growth direction.