Patent ID: 7396581

Claim:
A cutting tool insert comprising a substrate having a surface at least partially coated with a coating, the coating having a total thickness of about 10-40 μm, one or more refractory layers of which at least one layer is an alumina layer, the alumina layer comprising columnar α-Al 2 O 3 grains with texture coefficients expressed as TC(hkl) of: TC(012) and TC(024) both 2.5-3.5, wherein the 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 the (hkl) reflection I 0 (hkl)=standard intensity according to JCPDS card no 46-1212 n=number of reflections used in the calculation (hkl) reflections used are: (012), (104), (110), (113), (024), (116), wherein the coating comprises a first layer adjacent the substrate of CVD Ti(C,N), MTCVD Ti(C,N), or combinations thereof.