SURFACE COATED CUTTING TOOL EXCELLENT IN CHIPPING RESISTANCE

摘要

PROBLEM TO BE SOLVED: To provide a surface coated cutting tool in which a hard coating layer exhibits superior chipping resistance and peeling resistance in high-speed intermittent cutting conditions.SOLUTION: A surface coated cutting tool is coated with a lower layer which contains a TiCN layer having a NaCl type face-centered cubic crystal structure and an upper layer made of a TiAlCN layer which has a crystal structure of a NaCl type face-centered cubic crystal single phase or a crystal structure of a mixed phase of NaCl type face-centered cubic crystal and hexagonal crystal. Therein, when crystal orientation is analyzed with respect to the TiCN layer and the TiAlCN layer by using an electron beam back scattering diffraction device, such a crystal grain that an orientation difference between a normal direction of (hkl) plane of TiCN crystal grain of the lower layer and a normal direction of (hkl) plane of TiAlCN crystal grain of the upper layer is 5° or less, as crystal grains adjacent to each other via a boundary face between the upper layer and the lower layer, exists on the boundary face and such a crystal grain area proportion that a line density of the crystal grain is 2 pieces/10 μm or more and the orientation difference is 5° or less is 30 area % or more for the total area of the crystal grains adjacent via the boundary layer.SELECTED DRAWING: Figure 1