Patent ID: 7135221

Claim:
A cutting tool insert comprising: a cemented carbide substrate; and a coating, wherein the cemented carbide substrate comprises WC, 7 to 12 wt-% Co and 5 to 11 wt-% of cubic carbides of metals from groups IVb, Vb and VIb of the periodic table, a Co-binder that is highly alloyed with W and has an S-value of 0.79 to 0.89, a tungsten carbide phase having a mean intercept length of 0.7 to 1.4 μm, wherein the coating comprises at least one 2 to 12 μm alumina layer including columnar α-Al 2 O 3 grains and a texture coefficient TC(hkl) of (hkl) reflections (012), (104), (110), (113), (024), (116), wherein TC(012)>2.2 and TC(024)>0.6×TC(012), and wherein texture coefficient TC(hkl) is defined as TC ⁡ ( hkl ) = I ⁡ ( hkl ) I 0 ⁡ ( hkl ) ⁡ [ 1 n ⁢ ∑ I ⁡ ( hkl ) I 0 ⁡ ( hkl ) ] - 1 where I(hkl)=measured intensity of (hkl) reflection I 0 (hkl)=standard intensity according to JCPDS card no 46-1212 n=number of reflections used in calculation.