Patent ID: 8110075

Claim:
A method for making a cutting tool insert, comprising: preparing a substrate by milling, pressing and sintering a composition comprising: WC; 5.0-7.0 wt-% Co; 0.22-0.43 wt-% Cr; and wherein said substrate has a coercivity Hc of about 19-28 kA/m; and depositing a single layer of (Ti x Al 1-x )N on the substrate, where x is 0.25-0.50, with a crystal structure of NaCl configuration and a total thickness of about 3.0-5.0 μm, measured on the middle of the flank face with a compressive residual strain of about 2.5×10 −3 -5.0×10 −3 , and with a texture coefficient TC(200) of about 1.6-2.1, the texture coefficient (TC) being defined as: TC ⁡ ( hkl ) = I ⁡ ( hkl ) I 0 ⁡ ( hkl ) ⁡ [ 1 n ⁢ ∑ n = 1 n ⁢ I ⁡ ( hkl ) I 0 ⁡ ( hkl ) ] - 1 where I(hkl)=intensity of the (hkl) reflection, I O (hkl)=standard intensity according to JCPDS card no 38-1420, n=number of reflections used in the calculation, (hkl) reflections used are: (111), (200), (220), utilizing arc evaporation of an alloyed, or Ti+Al composite cathode, wherein the cathode comprises about 25-50 at-% Ti, and a current about 50-200, the substrate bias of about −20V to −35V, a deposition temperature of about 400° C.-700° C. and grown in an Ar+N 2 atmosphere containing 0-50 vol-% Ar, at a total pressure of 1.0 Pa to 7.0 Pa.