Cutting element with improved substrate material

Abstract

Cutting elements comprise a body and a polycrystalline diamond table disposed thereon, wherein the diamond table has a thickness of greater than about 2 mm. The body is specially formed from WC—Co and has a Co content of equal to or less than about 10 weight percent based on the total weight of the WC—Co, a coefficient of thermal expansion that is less than about 5×10 −6 /° C., a Palmqvist toughness greater than about 180 kg/mm, and a hardness equal to or greater than about 88 HRA. In an example, the WC has an average particle size of about 1 to 5 micrometers, the Co content is from about 7 to 9 weight percent, the coefficient of thermal expansion is from about 4 to 5×10 −6 /° C., the Palmqvist toughness is from about 200 to 300 kg/mm, and the hardness is in the range of from about 88 to 90 HRA.

What is claimed is: 
     
         1 . A cutting element comprising:
 a body formed from a material comprising WC—Co, the body comprising:   a Co content of equal to or less than about 10 weight percent based on the total weight of the WC—Co;   a coefficient of thermal expansion that is less than about 5×10 −6 /° C.;   a Palmqvist toughness greater than about 180 kg/mm; and   a hardness equal to or greater than about 88 HRA;   a polycrystalline diamond table bonded to the body and forming a wear surface of the cutting element.   
     
     
         2 . The cutting element as recited in  claim 1 , wherein the polycrystalline diamond table has a thickness that is greater than about 2 mm. 
     
     
         3 . The cutting element as recited in  claim 1 , wherein the polycrystalline diamond table has a thickness that is greater than about 5 mm. 
     
     
         4 . The cutting element as recited in  claim 1 , wherein the WC has an average particle size of between 1 to 5 micrometers. 
     
     
         5 . The cutting element as recited in  claim 1 , wherein the Co content is in the range of from about 7 to 9 weight percent. 
     
     
         6 . The cutting element as recited in  claim 1 , wherein the coefficient of thermal expansion is from about 4 to 5×10 −6 /° C. 
     
     
         7 . The cutting element as recited in  claim 1 , wherein the Palmqvist toughness is from about 200 to 300 kg/mm. 
     
     
         8 . The cutting element as recited in  claim 1 , wherein the hardness is from about 88 to 90 HRA. 
     
     
         9 . The cutting element as recited in  claim 1 , further comprising one or more transition layers of material interposed between the substrate and polycrystalline diamond table. 
     
     
         10 . The cutting element as recited in  claim 1 , wherein an interface between the body and the polycrystalline diamond table is smooth. 
     
     
         11 . The cutting element as recited in  claim 1 , wherein an interface between the body and the polycrystalline diamond table is nonsmooth. 
     
     
         12 . A bit for drilling subterranean formations comprising a number of cutting elements as recited in  claim 1  operatively attached thereto. 
     
     
         13 . A cutting element comprising:
 a body formed from a material comprising WC—Co, the body comprising:   a Co content of equal to or less than about 10 weight percent based on the total weight of the WC—Co;   a WC average particle size between about 1 to 5 micrometers; and   a coefficient of thermal expansion that is less than about 5×10 −6 /° C.;   a polycrystalline diamond table bonded to the body and forming a wear surface of the cutting element, the polycrystalline diamond table having an average thickness between about 2 to 10 mm.   
     
     
         14 . The cutting element as recited in  claim 13 , wherein the polycrystalline diamond table thickness is at least 5 mm. 
     
     
         15 . The cutting element as recited in  claim 13 , wherein the body has a Palmqvist toughness greater than about 180 kg/mm. 
     
     
         16 . The cutting element as recited in  claim 13 , wherein the body has a hardness greater than about 88 HRA. 
     
     
         17 . The cutting element as recited in  claim 13 , wherein the Co content is from about 7 to 10 weight percent. 
     
     
         18 . The cutting element as recited in  claim 13 , wherein the coefficient of thermal expansion is from about 4 to 5×10 −6 /° C. 
     
     
         19 . The cutting element as recited in  claim 13 , wherein the Palmqvist toughness is from about 200 to 300 kg/mm. 
     
     
         20 . The cutting element as recited in  claim 13 , wherein the hardness is from about 88 to 89 HRA. 
     
     
         21 . The cutting element as recited in  claim 13 , comprising one or more transition layers of material interposed between the body and the polycrystalline diamond table. 
     
     
         22 . The cutting element as recited in  claim 13 , wherein an interface between the body and the polycrystalline diamond table is smooth. 
     
     
         23 . The cutting element as recited in  claim 13 , wherein an interface between the body and the polycrystalline diamond table is nonsmooth. 
     
     
         24 . A bit for drilling subterranean formations comprising a number of cutting elements as recited in  claim 13  operatively attached thereto. 
     
     
         25 . A bit for drilling subterranean formations comprising:
 a body; and   a number of cutting elements connected with the body, the cutting elements comprising:   a substrate formed from a material comprising WC—Co, the substrate comprising:   a Co content of less than about 10 weight percent based on the total weight of the WC—Co;   a WC average particle size that is about 1 to 5 micrometers;   a coefficient of thermal expansion that is less than about 5×10 −6 /° C.;   a polycrystalline diamond table bonded to the substrate and forming a wear surface of the cutting element, the polycrystalline diamond table having an average thickness of at least 2.5 mm.   
     
     
         26 . The bit as recited in  claim 25 , further comprising a number of legs extending from the body and a cone rotatably disposed on each respective leg, wherein the cutting elements are attached to the cones. 
     
     
         27 . The bit as recited in  claim 25 , further comprising a number of fixed blades extending from the body, wherein the cutting elements are attached to the blades. 
     
     
         28 . The bit as recited in  claim 25 , wherein the polycrystalline diamond table thickness is at least 5 mm. 
     
     
         29 . The bit as recited in  claim 25 , wherein the substrate has a Palmqvist toughness greater than about 200 kg/mm. 
     
     
         30 . The bit as recited in  claim 28 , wherein the Palmqvist toughness is from about 200 to 300 kg/mm. 
     
     
         31 . The bit as recited in  claim 25 , wherein the substrate has a hardness greater than about 88 HRA. 
     
     
         32 . The bit as recited in  claim 30 , wherein the hardness is from about 88 to 90 HRA. 
     
     
         33 . The bit as recited in  claim 25 , wherein the Co content is from about 7 to 10 weight percent. 
     
     
         34 . The bit as recited in  claim 25 , wherein the coefficient of thermal expansion is from about 4 to 5×10 −6 /° C.