Patent ID: 8455116

Claim:
Cemented carbide cutting tool insert comprising a substrate and a wear resistant coating wherein: the substrate comprises WC, from about 5.5 to about 8.5 wt-% Co and Cr such that the Cr/Co weight ratio is from about 0.08 to about 0.12, and also Ti and Ta in such amounts that the ratio of Me/Co=(at % Ti+at % Ta)/at % Co is less than or equal to about 0.014−(CW—Cr)*0.008 and higher than about 0.0005 and CW—Cr is from about 0.75 to about 0.95, whereby the CW—Cr is defined as CW—Cr=(magnetic-% Co+1.13*wt-% Cr)/wt-% Co where magnetic-% Co is the weight percentage of magnetic Co and wt-% Co is the weight percentage of Co in the cemented carbide, the coercivity is more than about 20 kA/m, and the wear resistant coating is a homogeneous Al x Ti 1−x N-layer where x equals from about 0.6 to about 0.67, with thickness of more than about 1 μm, but less than about 3.8 μm, both composition and thickness being measured on the flank face about 0.2 mm below the nose radius and in the center of the cutting edge.