Patent ID: 7727621

Claim:
Cutting insert comprising a cemented carbide substrate and a multilayer coating wherein the substrate comprises WC, from about 8 to about 11 wt-% Co, and from about 0.1 to about 0.5 wt-% Cr, with coercivity in the range from about 18 to about 22 kA/m, and with a CW-ratio within from about 0.78 to about 0.90, and the multilayer coating comprises a laminar, aperiodic multilayered structure of A+B+A+B . . . where layers A and B are respectively, Al x Ti 1-x N and Ti y Al 1-y N in polycrystalline, non-repetitive form, with x=from about 0.4 to about 0.7, y=from about 0.6 to about 1, and x<y, with an average thickness of one A+B-sublayer within the range from about 30 to about 300 nm, varying essentially at random and with a total thickness of the multilayered coating of from about 0.5 μm to about 15 μm on the rake side and from about 2 to about 8 μm on the flank side.