Patent ID: 6062776
Filing Date: 2000-05-16
Classification: C22C,C23C,Y10T

Abstract:
A cutting tool insert having a cutting edge comprising a cemented carbide body and a coating wherein said cemented carbide body contains WC with an average grain size of 1.5-2.5 .mu.m, 10.9-13 wt-% Co and 0.2-1.8 wt-% TaC+NbC, and a low W-alloyed binder phase with a CW-ratio of 0.87-0.99 and said coating isa first layer of TiC.sub.x N.sub.y O.sub.z with x+y+z=1, with a thickness of 0.1-1.5 .mu.m, and with equiaxed grains with size <0.5 .mu.ma second layer of TiC.sub.x N.sub.y O.sub.z with x+y+z=1, with a thickness of 1-8 .mu.m with columnar grains with diameter of <5 .mu.m anda layer of a smooth, fine-grained .kappa.-Al.sub.2 O.sub.3 with a thickness of 0.5-5 .mu.m.