SURFACE COATED CERMET CUTTING TOOL WITH HARD COATING LAYER HAVING EXCELLENT CHIPPING RESISTANCE

摘要

PROBLEM TO BE SOLVED: To provide a surface coated cermet cutting tool with a hard coating layer having excellent thermal shock resistance. SOLUTION: This cutting tool has the hard coating layer formed on a surface of a tool base body constituted of WC base cemented carbide alloy or TiCN base cermet. The hard coating layer is constituted of the following (a) to (c) layers: (a) a Ti compound layer as a lower layer having a total average layer thickness of 3 to 20μm formed by deposition, (b) a heat transformedαtype Al2O3layer as an upper layer having a crystal structure of an Al2O3layer having aκtype orθtype crystal structure transformed into anαtype crystal structure by applying heat treatment to a surface of the Al2O3layer having theκtype orθtype crystal structure in a chemically depositioned state in a dispersed and distributed state of Ti oxide particulates formed by chemical deposition as a transformation generating crack initiating material and satisfying a specified composition formula: TiOx and having an average layer thickness of 1 to 15μm, and (c) a CrN layer formed by deposition as a surface layer and having an average layer thickness of 0.5 to 3μm. COPYRIGHT: (C)2006,JPO&NCIPI