SURFACE-COATED CUTTING TOOL HAVING HARD COATING LAYER FOR EXHIBITING SUPERIOR CHIPPING RESISTANCE AND ABRASIVE RESISTANCE IN HIGH SPEED HEAVY CUTTING WORK

摘要

PROBLEM TO BE SOLVED: To provide a surface-coated cutting tool having a hard coating layer for exhibiting superior chipping resistance and abrasive resistance in high speed heavy cutting work. SOLUTION: In this surface-coated cutting tool, the hard coating layer comprising a lower layer, an intermediate layer, and an upper layer is vapor deposited on the surface of a tool base. The lower layer comprises a Ti compound layer. The intermediate layer comprises an α-Al2O3layer with high (0001) surface orientation rate. The upper layer is a mixed structure layer comprising the mixed structure of an α-Al2O3phase and a ZrO2phase and contains more zirconium oxide on the surface side of the upper layer than on the intermediate layer side (tool base side) of the upper layer. The distribution of the lattice points sharing one constituent atom (constituent atom sharing lattice points) on the boundary surface of the mutually adjacent crystal grains in the crystal surfaces of the mixed structure layer is calculated. Where the configuration of the constituent atom sharing lattices of N in quantity in which the lattice points not sharing the constituent atoms are present between the constituent atom sharing lattice points is ΣN+1, the peak is present in Σ3, and the distribution rate of Σ3 to ΣN+1 is 35-70%. COPYRIGHT: (C)2010,JPO&INPIT