Patent ID: RE39912

Claim:
A cutting tool insert for milling of grey cast iron with or without cast skin under wet conditions at low and moderate cutting speeds and milling of nodular cast iron and compacted graphite iron under wet conditions at moderate cutting speeds, comprising: a cemented carbide body comprising WC, 7.3-7.9 wt. % Co, 1.0-1.8 wt. % cubic carbides of Ta and Nb, and a highly W-alloyed binder phase with a CW-ratio of 0.86-0.94; a coating comprising a first, innermost layer of TiC x N y O z with x+y+z= 1, y<x y>x and z<0.2 having an equiaxed grain structure with a size <0.5 μm and a total thickness of 0.1-1.5 μm; a layer of TiC x N y with x+y= 1, x<0.3 x>0.3 and y< 0 . 3 y> 0 . 3 with a thickness of 1-4 μm having a columnar grain structure with an average diameter of <5 μm; a layer of a smooth, fine-grained, 0.5-2 μm κ-Al 2 O 3 with a thickness of 1-2.5 μm; and an outer layer of TiN with a thickness of 0.5-1.0 μm.