Patent ID: 8187430

Claim:
A method for making a cutting tool insert having a flank face, comprising a cemented carbide body and a coating, comprising the steps of: providing a substrate made by conventional powder metallurgical methods milling, pressing, and sintering with a composition comprising: tungsten carbide (WC); about 4.0 wt-% to about 7.0 wt-% cobalt (Co); about 0.25 wt-% to about 0.50 wt-% chromium (Cr); and wherein said composition has a coercivity, Hc, of about 28 kA/m to about 38 kA/m; and depositing a single layer, comprising (Ti 1-x Si x )N, wherein x is between about 0.1 and about 0.25; wherein said layer has a crystal structure of NaCl type and a total thickness of between 0.5 μm and 2.0 μm measured on the middle of said flank face; wherein said layer has a texture coefficient TC(200)>about 1.5, 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), using arc evaporation of an alloyed, or Ti+Si composition cathode having a composition comprising: about 60 at-% Ti to about 90 at-% Ti, and balance Si; with an evaporation current of between about 50 A and about 200 A and a substrate bias of between about −10 V and about −150 V, and a deposition temperature of between about 400° C. and about 700° C., and grown in an Ar+N 2 atmosphere comprising about 0 vol-% Ar to about 50 vol-% Ar, at a total pressure of about 0.5 Pa to about 9.0 Pa.