Patent ID: 8053064

Claim:
A cutting tool insert, comprising: a cemented carbide body; and a coating; wherein said body has a composition comprising: about 7.5-8.6 wt% Co; about 0.5-2.5 wt-% of metals selected from the group consisting of Group IVb metal, Group Vb metal, Group VIb metal, and combinations thereof; balance WC; wherein said body has a coercivity of about 12.0-15.5 kA/m and an S-value of about 0.81-0.95; and wherein said coating consists of: a first (innermost) layer of TiC x N y O z with about 0.7≦x+y+z≦about 1 with equiaxed grains and a total thickness <about 1 μm; a second layer of TiC x N y O z with about 0.7≦x+y+z≦about 1 and a thickness of about 1-5 μm with columnar grains; and a strongly textured α-Al 2 O 3 outer layer having a thickness of about 1-5 μm.