| 摘要 |
PURPOSE: To provide a coated cutting tool insert that shows superior performance in turning of cast iron. CONSTITUTION: The coated cutting tool insert comprises a cemented carbide body and a coating and is particularly useful in turning of cast iron, wherein the cemented carbide body has a composition comprising 3.0 to 9.0 wt.%, preferably 4.0 to 7.0 wt.% of Co, more than 4.0 to 10.0 wt.%, preferably 6.0 to 9.0 wt.% of cubic carbonitride forming elements selected from groups IVb and Vb of the periodic table and the balance being N, C and WC and has a surface region of which thickness is 5 to 50μm, preferably 10 to 40μm, and on which a binder phase is enriched, but a cubic carbonitride phase hardly exists, the maximum content of the binder phase on the surface region being 1.2 to 3 by volume of content of a bulk binder phase; and the coating comprises a first innermost layer of TiCxNyOz (where 0.7<=x+y+z<=1, preferably z<0.5, more preferably y>x, and z<0.2, most preferably y>0.7, grains being equiaxed grains, and the total thickness being less than 2μm, preferably exceeding 0.1μm), a TiCxNyOz layer (where 0.7<=x+y+z<=1, preferably z<0.2, x>0.3, and y>0.2, most preferably x>0.4, thickness being 3 to 14μm, preferably 4 to 12μm, most preferably 5 to 10μm, and grains being columnar grains), and at least one Al2O3 layer (where thickness being 2 to 14μm, preferably 3 to 10μm, and most preferably 3 to 8μm). |
