Patent ID: 9725811
Date: 2017-08-08
CPC Classifications: B23B,C01B,C23C

Claim:
1. A coated cutting tool which comprises a substrate and a coating layer formed on a surface of the substrate, at least one layer of the coating layer being a coarse grain layer having an average grain diameter Lx measured at a direction parallel to an interface of the coating layer and the substrate exceeding 200 nm, and a composition of which being represented by (Al a grain diameter ratio (Ly/Lx) of an average grain diameter Ly of the coarse grain layer measured at a direction perpendicular to an interface between the coating layer and the substrate to said average grain diameter Lx of the coarse grain layer measured at a direction parallel to an interface between the coating layer and the substrate is 0.7 or more and less than 1.5, M represents at least one kind of an element(s) selected from the group consisting of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, B and Si, X represents at least one kind of an element(s) selected from the group consisting of C, N and O, a represents an atomic ratio of an Al element based on a total of the Al element, a Ti element and an M element, b represents an atomic ratio of a Ti element based on a total of an Al element, the Ti element and an M element, c represents an atomic ratio of an M element based on a total of an Al element, a Ti element and the M element, a, b and c each satisfy 0.30≦a≦0.65, 0.35≦b≦0.70, 0≦c≦0.20 and a+b+c=1, and an average layer thickness of the coarse grain layer being 0.2 to 10 μm.