US Patent RE40005 Coated cutting insert

There is disclosed a coated cutting insert particularly useful for cutting in cast iron materials. The insert is characterized by a straight WC-Co cemented carbide body having a highly W-alloyed Co binder phase, a well-defined surface content of Co and a coating including an innermost layer of TiCxNyOz with columnar grains, a layer of a fine-grained, textured Al2O3 layer and a top layer of TiCxNyOz that has been removed along the cutting edge line.