Patent ID: 6217992
Filing Date: 2001-04-17
Classification: C23C,Y10T

Abstract:
A cutting insert comprising:a rake face and a flank face, a cutting edge at the juncture of the rake face and the flank face;the cutting insert having a coating and a substrate wherein the coating is adherently bonded to the substrate; the substrate being a tungsten carbide-based ceramic carbide having a bulk composition comprising:the substrate being a tungsten carbide-based cemented carbide having a bulk composition comprising:at least about 70 weight percent tungsten carbide,at least about 3 weight percent cobalt, andsolid solution carbides and/or carbonitrides of tungsten and one or more of one of tantalum, niobium, titanium, hafnium, zirconium, and vanadium;wherein the cobalt concentration being enriched in a zone of non-stratified cobalt enrichment beginning near and extending inwardly from a peripheral surface of the substrate, the enriched zone having a maximum cobalt concentration of between about 125 and about 300 percent of the cobalt in the bulk substrate;the zone of non-stratified cobalt enrichment being at least partially depleted of the solid solution carbides and/or solid solution carbonitrides; andwherein the bulk substrate having a porosity according to ASTM Designation B 276-86 of greater than C00 and less than or equal to C02.