| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface-coated cutting tool which exhibits superior abnormal damage resistance in high-speed intermittent cutting.SOLUTION: In a surface-coated cutting tool in which a hard coating layer comprising a lower layer and an upper layer is formed by coating, (a) the lower layer is made of a Ti compound layer having a layer thickness of 3 to 15 μm and has one carbonitride layer, (b) the upper layer is made of a chemically deposited α type aluminum oxide layer having a layer thickness of 2 to 20 μm, (c) in a Ti carbonitride layer (hereinafter called as the thickest Ti carbonitride layer ) constituting the lower layer and having a layer thickness of 1.5 μm or more being the thickest layer among the lower layer, a crack origins layer in which fine vacancies having an average diameter of 25 to 200 nm exist with an average density of 3 or more and less than 20 pieces/μmis formed in a region of 1/3 to 2/3 of layer thickness of the thickest Ti carbonitride layer, with a thickness from 0.5 μm to a thickness of 1/3 of the thickest Ti thickest carbonitride layer, and (d) a stress relaxation layer in which cracks exist with an average density of 0.2 or more and less than 2 pieces/μm is formed from the crack origins layer to the lower layer of the base body side. |
