SURFACE COATING CUTTING TOOL

摘要

A surface-coated cutting tool with a body and hard coating layer is provided. (a) The hard coating layer is made of a complex nitride layer of Al and Cr. (b) The hard coating layer deposited on a region from a cutting edge to a location 100 µm from the cutting edge toward an opposite side thereof has a granular crystal structure. The average grain size of granular crystals on a surface of the hard coating layer on the region is 0.2-0.5 µm. The average grain size of granular crystals at an interface between the cutting tool body and the hard coating layer on the region is smaller than the average grain size on the surface the hard coating layer in an extent of 0.02-0.1 µm. The crystal grain size length ratio of crystal grains whose size is 0.15-20% or less.