Coated cutting tool insert

摘要

Coated cemented carbide inserts (cutting tool), particularly useful for milling at high cutting speeds in steels and milling in hardened steels are characterised by a WC-Co cemented carbide containing NbC and TaC and a W-alloyed binder phase and a coating including a first, innermost layer of TiC_xN_yO_z with equiaxed grains, a second layer of TiC_xN_yO_z with columnar grains and at least one layer of Al₂O₃ composed primarily of the kappa-phase.