SURFACE-COATED CUTTING TOOL HAVING HARD COATING LAYER EXERTING EXCELLENT CHIPPING RESISTANCE AND WEAR RESISTANCE

摘要

PROBLEM TO BE SOLVED: To provide a surface-coated cutting tool exerting excellent chipping resistance and wear resistance in a wet-process high-speed intermittent cutting process of a material to be cut such as a stainless steel poor in thermal conductivity.SOLUTION: There is provided a surface-coated cutting tool formed by coating an α type aluminum oxide layer on the surface of a tool substrate directly or via a lower layer comprising a Ti compound by a sol-gel method. The fine holes having the average hole size of 10 to 100 nm are dispersed and formed, and the average density of the fine holes measured on the longitudinal section of the α type aluminum oxide layer is 30 to 70 pieces/μm. The fine holes are uniformly dispersed and distributed, and a standard deviation when obtaining the hole density in the range of a prescribed observation view over the number of the prescribed views is 15 pieces/μmor less. The number ratio of the fine holes in which Ti oxide is formed adjacently to the fine hole at least a part of the periphery of the fine hole is 50% or more of the number of the whole fine holes.SELECTED DRAWING: Figure 1