Cutting tool.

摘要

A coated cemented carbide tool insert with a lengthened life is provided which comprises a substrate of a cemented carbide and a coating film provided thereon consisting of one or more layers 2 to 20 mu m in thickness of a compound with a higher hardness than the substrate, in which at least the surface of the coating film, on and near the ridgeline of the cutting tip, of the tool is substantially composed of a smooth surface with a surface roughness Rmax of at most 0.2 mu m to the standard length of 5 mu m.