SURFACE-COATED CERMET CUTTING TOOL HAVING HARD-COATING LAYER EXHIBITING EXCELLENT CHIPPING RESISTANCE IN HIGH-SPEED CUTTING OF DIFFICULT-TO-MACHINE MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide a surface-coated cermet cutting tool having a hard-coating layer exhibiting excellent chipping resistance in high-speed cutting of a difficult-to-machine material.;SOLUTION: In production of a surface layer of the hard coating layer of the surface coated cermet cutting tool, every crystal grain having a hexagonal crystal lattice, present in a measurement range of a polishing surface, is irradiated with electron beams by using a field emission scanning electron microscope, and an inclination angle of a normal of a crystal plane of the crystal grain, with respect to a normal of the polishing surface, is measured. Then based on the measured inclination angle obtained as a result of the measurement, distribution of lattice points at which each constituent atom shares a single constituent atom between the crystal grain phases, in an interface between the crystal grains adjacent to each other, and provided that a constituent atom covalent lattice point form in which N lattice points sharing no constituent atom between the constituent atom covalent lattice points is represented by ΣN+1, the surface layer is formed of a modified Cr₂O₃ layer showing a constituent atom covalent lattice distribution graph in which a highest peak is present at Σ3, and at the same time a distribution percentage of Σ3 accounting for the entire amount of ΣN+1 is 60% or more.;COPYRIGHT: (C)2007,JPO&INPIT