Ceramic cutting insert of polycrystalline tungsten carbide

Abstract

A polycrystalline tungsten carbide ceramnic cutting insert with chip control is disclosed for high speed machining.

What is claimed is:  
     
         1 . A ceramic cutting insert for high speed machining consisting essentially of polycrystalline tungsten carhbide comprising: 
 (a) a cutting edge;    (b) a rake face with a chip control groove surface;    (c) a flank face;    wherein the cutting edge is formed at the juncture of the flank face and the rake face.    
     
     
         2 . The ceramic cutting insert of  claim 1 , wherein the flank face is in an as molded or ground condition.  
     
     
         3 . The ceramic cutting insert of  claim 1 , wherein the chip control groove surface is in an as molded or ground condition.  
     
     
         4 . The ceramic cutting insert of  claim 2 , wherein the chip control groove surface and the flank face are each in an as molded condition.  
     
     
         5 . The ceramic cutting insert of  claim 1 , wherein the polycrystalline tungsten carbide: 
 (a) has a density of at least 95% of its theoretical density; and    (b) an average grain size of 0.001 to 10 micrometers.    
     
     
         6 . The ceramic cutting insert of  claim 5 , wherein the polycrystalline tungsten carbide has an average grain size of 0.2 to 4 micrometers.  
     
     
         7 . The ceramic cutting insert of  claim 5 , wherein the polycrystalline tungsten carbide comprises at least 98.5% by volume tungsten carbide.  
     
     
         8 . The ceramic cutting insert of  claim 5 , wherein the polycrystalline tungsten carbide comprises 99% by volume tungsten carbide.  
     
     
         9 . The ceramic cutting insert of  claim 5 , wherein the polycrystalline tungsten carbide has the density of at least 98% of its theoretical density.  
     
     
         10 . The ceramic cutting insert of  claim 5 , wherein an iron group element is present from about 0.01% to about 1% by volume.  
     
     
         11 . The ceramic cutting insert of  claim 10 , wherein the iron group element is cobalt.  
     
     
         12 . The ceramic cutting insert of  claim 11 , wherein cobalt is present from about 0.01% to about 1.0% by volume.  
     
     
         13 . The ceramic cutting insert of  claim 11 , wherein the cobalt is present at about 0.25% by volume.  
     
     
         14 . The ceramic cutting insert of  claim 5 , wherein a carbide, nitride, oxide and/or boride have a free energy of formation less than that of the respective carbide, nitride, oxide and/or boride of tungsten is present in the amount from about 0.1% to about 1% by volume.