Patent ID: RE39884

Claim:
A cutting tool insert for milling low and medium alloyed steels with or without raw surfaces during wet or dry conditions comprising a cemented carbide body and a coating wherein said cemented carbide body comprises WC, 8.6-9.5 wt-% Co and 0.2-1.8 wt-% cubic carbides of Ta, Ti and Nb, with Ti present on a level corresponding to a technical impurity, and a highly W-alloyed binder phase with a CW-ratio of 0.78-0.93 and said coating comprises a first (innermost) layer of TiC x N y O z with x+y+z=1, with a thickness of 0.1-1.5 μm, and with equiaxed grains with size <0.5 μm a second layer of TiC x N y O z with x+y+z=1, with a thickness of 1-6 μm with columnar grains with diameter of <5 μm and a layer of a smooth, fine-grained (0.5-2 μm) κ-Al 2 O 3 with a thickness of 0.5-5 μm.