Methods of making cemented carbide inserts for earth-boring bits

Abstract

This invention relates to cuffing inserts for earth boring bits comprising a cutting zone, wherein the cutting zone comprises first cemented hard particles and a body zone, wherein the body zone comprises second cemented hard particles. The first cemented hard particles may differ in at least one property from the second cemented hard particles. As used herein, the term cemented hard particles means a material comprising hard particles in a binder. The hard particles may be at least one of a carbide, a nitride, a boride, a silicide, an oxide, and solid solutions thereof and the binder may be at least one metal selected from cobalt, nickel, iron and alloys of cobalt, nickel or iron.

1 - 10 . (canceled) 
     
     
         11 . A method of preparing a cutting insert for an earth-boring bit, the method comprising:
 partially filling a mold with a first cemented hard particle powder;   filling at least a portion of the remaining portion of the mold with a second cemented hard particle powder;   consolidating the first and second cemented hard particle powders into a single green compact; and   sintering the single green compact.   
     
     
         12 . The method of  claim 11 , wherein sintering the single green compact is performed at a temperature between 1300° C. and 1500° C. 
     
     
         13 . The method of  claim 11 , wherein at least one of the first cemented hard particle powder and the second cemented hard particle powder is a cemented carbide powder. 
     
     
         14 . The method of  claim 11 , wherein at least one of the first cemented hard particle powder and the second cemented hard particle powder comprises a recycled cemented carbide powder. 
     
     
         15 . The method of  claim 13 , wherein the cemented carbide powder comprises:
 a carbide of at least one transition metal selected from titanium, chromium, vanadium, zirconium, hafnium, tantalum, molybdenum, niobium, and tungsten; and   a binder comprising cobalt, a cobalt alloy, nickel, a nickel alloy, iron, and an iron alloy.   
     
     
         16 . The method of  claim 15 , wherein the binder further comprises an alloying agent selected from tungsten, titanium, tantalum, niobium, chromium, molybdenum, boron, carbon, silicon, and ruthenium. 
     
     
         17 . The method of  claim 13 , wherein the cemented carbide powder comprises a hybrid cemented carbide powder, the hybrid cemented carbide powder comprising a plurality of first cemented carbide grade particles and a plurality of second cemented carbide grade particles. 
     
     
         18 . The method of  claim 11 , wherein sintering the single green compact provides a sintered compact comprising a first region of a first cemented hard particle material autogenously bonded to a second region of a second cemented hard particle material. 
     
     
         19 . The method of  claim 13 , wherein:
 sintering the single green compact provides a sintered compact comprising a first region of a first cemented hard particle material autogenously bonded to a second region of a second cemented hard particle material; and   wherein at least one of the first cemented hard particle material and the second cemented hard particle material is a cemented carbide including
 a carbide of at least one transition metal selected from titanium, chromium, vanadium, zirconium, hafnium, tantalum, molybdenum, niobium, and tungsten, and 
 a binder comprising cobalt, a cobalt alloy, nickel, a nickel alloy, iron, and an iron alloy. 
   
     
     
         20 . The method of  claim 17 , wherein sintering the single green compact provides a sintered compact comprising a first region of a first cemented hard particle material autogenously bonded to a second region of a second cemented hard particle material, and wherein at least one of the first cemented hard particle material and the second cemented hard particle material is a hybrid cemented carbide. 
     
     
         21 . A method of preparing a cutting insert for an earth-boring bit, the method comprising:
 consolidating a first cemented carbide powder in a mold to provide a first green compact;   placing the first green compact in a second mold, wherein the first green compact fills a portion of the second mold;   filling at least a portion of a remaining portion of the second mold with a second cemented carbide powder;   consolidating the second cemented carbide powder and the first green compact together to form a second compact; and   sintering the second compact.   
     
     
         22 . The method of  claim 21 , wherein at least one of the first cemented carbide powder and the second cemented carbide powder comprises a recycled cemented carbide powder. 
     
     
         23 . The method of  claim 21 , further comprising, prior to placing the first green compact in the second mold, presintering the first green compact at a temperature up to 1250° C. 
     
     
         24 . The method of  claim 21 , wherein sintering the second compact comprises heating the second compact at a temperature between 1300° C. and 1500° C. 
     
     
         25 . The method of  claim 21 , wherein the first cemented carbide powder and the second cemented carbide powder independently comprise:
 a carbide of at least one transition metal selected from titanium, chromium, vanadium, zirconium, hafnium, tantalum, molybdenum, niobium, and tungsten; and   a binder comprising cobalt, a cobalt alloy, nickel, a nickel alloy, iron, and an iron alloy.   
     
     
         26 . The method of  claim 25 , wherein the binder further comprises an alloying agent selected from tungsten, titanium, tantalum, niobium, chromium, molybdenum, boron, carbon, silicon, and ruthenium. 
     
     
         27 . The method of  claim 21 , wherein at least one of the first cemented carbide powder and the second cemented carbide powder comprises a hybrid cemented carbide powder, the hybrid cemented carbide powder comprising a plurality of first cemented carbide grade particles and a plurality of second cemented carbide grade particles. 
     
     
         28 . The method of  claim 21 , wherein sintering the second compact provides a sintered compact comprising a first region of a first cemented carbide autogenously bonded to a second region of a second cemented carbide. 
     
     
         29 . The method of  claim 25 , wherein sintering the second compact provides a sintered compact comprising a first region of a first cemented carbide autogenously bonded to a second region of a second cemented carbide, and wherein the first cemented carbide and the second cemented carbide individually comprise:
 a carbide of at least one transition metal selected from titanium, chromium, vanadium, zirconium, hafnium, tantalum, molybdenum, niobium, and tungsten; and   a binder comprising cobalt, a cobalt alloy, nickel, a nickel alloy, iron, and an iron alloy.   
     
     
         30 . The method of  claim 27 , wherein sintering the second compact provides a sintered compact comprising a first region of a first cemented carbide autogenously bonded to a second region of a second cemented carbide, and wherein at least one of the first cemented carbide and the second cemented carbide is a hybrid cemented carbide. 
     
     
         31 . A method of preparing a cutting insert for an earth-boring bit, comprising:
 pressing a first cemented carbide powder and a second cemented carbide in a mold to form a green compact, wherein at least one of the first cemented carbide and the second cemented carbide powder comprise a recycled cemented carbide powder; and   sintering the green compact.