Patent ID: 8043729

Claim:
A cutting insert comprising a cemented carbide body and a coating wherein said cemented carbide body has a composition of from about 12.5 to about 14.5 wt % Co, from about 0.52 to about 0.64 wt % Cr, balance WC, with a CW-ratio in the range of from about 0.76 to about 0.84 and a polarization coercivity, HcJ, value in the range of from about 12.5 to about 14.5 kA/m; said insert being at least partly coated with an from about 4.1 to about 6.9 μm thick coating including at least three layers of TiC x N y O z of which one is adjacent to the cemented carbide and a blasted α-Al 2 O 3 -layer being the outer layer at least on the rake face, the TiC x N y O z layers having a total thickness of from about 1.9 to about 3.6 μm comprising: a first TiC x N y O z layer adjacent to the cemented carbide having a composition of x+y=1, x equal to or greater than about 0, a second TiC x N y O z layer having a composition of x more than about 0.4, y more than about 0.4 and z is equal to or greater than about zero but less than about 0.1, a third TiC x N y O z layer adjacent to the α-Al 2 O 3 -layer having a composition of x+y+z equal to or more than about 1 and z more than about 0, and the α-Al 2 O 3 -layer having a thickness of from about 1.8 to about 3.6 μm with flattened grains on the surfaces that have been subjected to the blasting treatment.