# US 7,407,525 B2 · Fracture and wear resistant compounds and down hole cutting tools > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,407,525 B2 - Document ID: US7407525B2 - Status: Granted - Kind: B2 - Application number: 10/700,693 - Filed: 2003-11-04 - Published: 2004-07-22 - Granted: 2008-08-05 - Earliest claimed: 2001-12-14 - Assignees: Smith International, Inc. - Inventors: Dah-Ben Liang - Web page: https://patentgrep.com/patent/US7407525B2 ## CPC - E21B 10/567: with preformed cutting elements mounted on a distinct support, e.g. polycrystalline inserts - C22C 29/08: based on tungsten carbide - C23C 30/005: {on hard metal substrates} - E21B 10/08: Roller bits (E21B10/26 takes precedence; roller core bits E21B10/06; characterised by wear resisting parts E21B10/50) - E21B 10/52: with chisel- or button-type inserts - E21B 17/1085: {Wear protectors; Blast joints; Hard facing} - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - C22C: ALLOYS (treatment of alloys C21D, C22F) - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) ## Abstract Fracture and wear resistant cutting elements are provided. Examples include a cutting element formed of a wear resistant material having a binder composition and a coarse grain size such that the portion of the cutting element formed of the wear resistant material has a fracture toughness of at least about 18 ksi(in)0.5 and a wear number of at least about 1.8. In a particular example, the wear resistant material has a fracture toughness of at least about 20 ksi(in)0.5. A down hole cutting tool incorporating such cutting elements is also provided. ## Claims ### Claim 1 A cutting element for a rock bit used to drill wellbores through earth formation, the cutting element comprising: wear resistant material, the wear resistant material comprising coarse grains disposed in a binder matrix; the coarse grains comprising grains of at least one selected from the group of a transition metal carbide, a transition metal boride, and transition metal nitride, the wear resistant material having a binder composition and a coarse grain size such that the wear resistant material has a fracture toughness of at least 20 ksi (in)0.5 and a wear number of at least 1.8. ### Claim 2 (depends on 1) The cutting element of claim 1, wherein the fracture toughness is at least about 21 ksi (in)0.5. ### Claim 3 (depends on 1) The cutting element of claim 1, wherein the fracture toughness is between 20 ksi (in)0.5 and 27 ksi (in)0.5. ### Claim 4 (depends on 1) The cutting element of claim 1, wherein the grains comprise tungsten carbide particles and the binder material comprises cobalt, and wherein the wear resistant material comprises between about 10% and about 16% by weight cobalt. ### Claim 5 (depends on 4) The cutting element of claim 4, wherein the wear number is between about 1.8 and about 2.5. ### Claim 6 (depends on 4) The cutting element of claim 4, wherein the wear resistant material comprises between 12% and 16% by weight cobalt. ### Claim 7 (depends on 6) The cutting element of claim 6, wherein the wear number is between about 1.9 and about 2.3. ### Claim 8 (depends on 1) The cutting element, of claim 1, wherein the wear resistant material has a hardness in a range of about 83 to about 86 Rockwell A. ### Claim 9 A drill bit for drilling wellbores through earth formation, the drill bit comprising: a plurality of cutting elements mounted on a cutting structure, wherein at least one of the plurality of cutting elements comprises a wear resistant material, the wear resistant material comprising coarse grains disposed in a binder matrix, the coarse grains comprising grains of at least one selected from the group of a transition metal carbide, a transition metal boride, and transition metal nitride, the wear resistant material having a binder composition and a coarse grain size such that the wear resistant material has a fracture toughness of at least 20 ksi (in)0.5 and a wear number of at least 1.8. ### Claim 10 (depends on 9) The drill bit of claim 9, wherein the fracture toughness is at least about 21 ksi (in)0.5. ### Claim 11 (depends on 9) The drill bit of claim 9, wherein the fracture toughness is between 20 ksi (in)0.5 and 27 ksi (in)0.5. ### Claim 12 (depends on 9) The drill bit of claim 9, wherein the grains comprise tungsten carbide particles and the binder material comprises cobalt, and wherein the wear resistant material comprises between about 10% and about 16% by weight cobalt. ### Claim 13 (depends on 12) The drill bit of claim 12, wherein the wear number is between about 1.8 and about 2.5. ### Claim 14 (depends on 12) The drill bit of claim 12, wherein the wear resistant material comprises between 12% and 16% by weight cobalt. ### Claim 15 (depends on 14) The drill bit of claim 14, wherein the wear number is between about 1.9 and about 2.3. ### Claim 16 (depends on 9) The drill bit of claim 9, wherein the wear resistant material has a hardness in a range of about 83 to about 86 Rockwell A. ### Claim 17 (depends on 9) The drill bit of claim 9, wherein the drill bit has a bit body, and the cutting structure comprises at least one roller cone rotatably coupled to the bit body, and the at least one of the plurality of cutting elements is disposed on the at least one roller cone. ### Claim 18 (depends on 9) The drill bit of claim 9, wherein the drill bit has a bit body, and the cutting structure comprises a plurality of radially extending blades disposed at one end of the bit body, and the at least one cutting element is disposed on at least one of the blades. ### Claim 19 A cutting element for a rock bit used to drill wellbores through earth formation, the cutting element, comprising: wear resistant material, the wear resistant material comprising coarse grains disposed in a binder matrix, the coarse grains comprising grains of at least one selected from the group of a transition metal carbide, a transition metal boride, and transition metal nitride, the wear resistant material having a binder composition and a coarse grain size such that the fracture toughness and the wear number of the wear resistant material generally follow the relationship: y=62.085·x(−1.3676) wherein y is the fracture toughness which is greater than or equal to 20 ksi (in)0.5, and x is the wear number, within a range defined by a coefficient of determination, R2, of about 0.86. ### Claim 20 (depends on 19) The cutting element of claim 19, wherein the wear resistant material has a fracture toughness in the range of 20 ksi (in)0.5 to about 27 ksi (in)0.5. ### Claim 21 (depends on 19) The cutting element of claim 19, wherein the wear resistant material also has a hardness of between about 83 to about 86 Rockwell A. ### Claim 22 (depends on 19) The cutting element of claim 19, wherein the binder composition comprises a cobalt content of between about 10% and about 16% by weight cobalt. ### Claim 23 A drill, bit for drilling wellbores through earth formation, the drill bit; comprising: a plurality of cutting elements mounted on a cutting structure, wherein at least one of the plurality of cutting elements is formed from wear resistant material, the wear resistant material comprising coarse grains disposed in a binder matrix, the coarse grains comprising grains of at least one selected from the group of a transition metal carbide, a transition metal boride, and transition metal nitride, the wear resistant material having a binder composition and a coarse grain size such that the fracture toughness and the wear number generally satisfy the relationship: y=62.085·x(−1.3676), wherein y is the fracture toughness which is greater than or equal to 20 ksi (in)0.5, and x is the wear number, within a range defined by a coefficient of determination, R2, of about 0.86. ### Claim 24 (depends on 23) The drill bit of claim 23, wherein the wear resistant material has a fracture toughness in the range of 20 ksi (in)0.5 to about 27 ksi (in)0.5. ### Claim 25 (depends on 23) The drill bit of claim 23, wherein the wear resistant material has a hardness of between about 83 to about 86 Rockwell A. ### Claim 26 (depends on 23) The drill bit of claim 23, wherein the wear resistant material has the binder composition of between about 10% and about 16% by weight cobalt. ### Claim 27 (depends on 23) The drill bit of claim 23, wherein the cutting tool comprises a drill bit including a bit body, wherein the cutting structure comprises at least one roller cone rotatably coupled to the bit body, and the at least one cutting element is disposed on the at least one roller cone. ### Claim 28 (depends on 23) The drill bit of claim 23, wherein the cutting tool comprises a drill bit including a bit body, and the cutting structure comprises a plurality of radially extending blades disposed on an end of the bit body, and the at least one cutting element is disposed on at least one of the blades. ### Claim 29 (depends on 1) The cutting element of claim 1, wherein the wear resistant material comprises coarse grains having an average grain size of greater than 6 μm. ### Claim 30 (depends on 29) The cutting element of claim 29, wherein the wear resistant material comprises coarse grains having an average grain size of around 9 μm or more. ### Claim 31 (depends on 9) The drill bit of claim 9, wherein the wear resistant material comprises coarse grains having an average grain size of greater than 6 μm. ### Claim 32 (depends on 31) The drill bit of claim 31, wherein the wear resistant material comprises coarse grains having an average grain size of around 9 μm or more. ### Claim 33 A drill bit used to drill wellbores through earth formation, the drill bit comprising: a plurality of cutting elements mounted on a cutting structure, wherein at least one of the plurality of cutting elements is formed of a wear resistant material comprising coarse grains of tungsten carbide disposed in a cobalt binder matrix, the tungsten carbide grains having an average grain size of around 9 μm, and the wear resistant material having a cobalt binder content of between about 10% and about 16% by weight. ### Claim 34 (depends on 33) The drill bit of claim 33, wherein the drill bit further comprises a bit body, and the cutting structure comprises at least one roller cone rotatably coupled to the bit body, and the at least one cutting element is disposed on the at least one roller cone. ### Claim 35 (depends on 34) The drill bit of claim 34, wherein the at least one roller cone comprises three roller cones, and a plurality of cutting elements disposed on each of said roller cones is formed entirely of said wear resistant material. ### Claim 36 (depends on 34) The drill bit of claim 34, wherein said at least one cutting element is disposed on a gage row of said at least one roller cone. ### Claim 37 (depends on 34) The drill bit of claim 34, wherein the wear resistant material has a cobalt binder content of between about 12% and about 16% by weight.