COATED PCBN CUTTING TOOLS

摘要

The present invention provides a coated sintered body which can be used in precious machining hardened steel. The coated PCBN cutting tool comprises a substrate which contains not le ss than 35 volume % and not more than 85 volume % of CBN, and a hard coated layer formed on the substrate. The hard coated layer comprises at least one compound layer consisting of at least one element selected from a group of 4 a, 5a, 6a elements of the periodic table and Al, and at least one element selected from a group of C, N and O. The thickness of the layer is not less than 0.3 .mu. m and not more than 10 .mu. m. The center -line mean roughness of the hard coated layer is not more than 0.1 .mu. m.