Earth boring drill bit with improved wear inserts

Claim 2

An improved insert for use in a rotary rock bit of the type adapted to be made up in a drill string extending from the surface of the earth down a borehole, the improved insert comprising a diamond impregnated carbide containing dispersed diamond crystals, the crystals being formed via the in-situ conversion of graphite to diamond.

Claim 3

The improved insert of claim 1, wherein the diamond impregnated carbide is diamond impregnated tungsten carbide having diamond crystals dispersed around individual grains of tungsten carbide, the diamond crystals being intergrown and intertwined with the individual carbide grains of the insert.

Claim 4

The improved insert of claim 2, wherein the particle size of the dispersed diamonds which are formed in-situ and the particle size of the individual tungsten carbide grains are both in the range from about 0.2 to 1000 microns.

Claim 5

The improved insert of claim 3, wherein the particle size of the dispersed diamonds which are formed in-situ and the particle size of the individual tungsten carbide grains are both in the range from about 2 to 5 microns.

Claim 6

An improved earth boring bit of the type having rotary cutters defining a cutting structure for boring a hole, the cutters being mounted rotatably on a shank, the improvement comprising wear inserts on the cutting structure, the wear inserts comprising a diamond impregnated carbide containing dispersed diamond crystals, the crystals being formed via the in-situ conversion of graphite to diamond.

Claim 7

An improved earth boring bit of the type having rotary cutters defining a cutting structure for boring a hole, the cutters being mounted rotatably on a shank, the improvement comprising wear inserts on the cutting structure, the wear inserts comprising a diamond impregnated carbide containing dispersed diamond crystals, the crystals being formed via the in-situ conversion of graphite to diamond.

Claim 8

An improved earth boring bit of the type having rotary cutters defining a cutting structure for boring a hole, the cutters being mounted rotatably on a shank, the improvement comprising wear inserts on the cutting structure, the wear inserts comprising a diamond impregnated carbide containing dispersed diamond crystals, the crystals being formed via the in-situ conversion of graphite to diamond, the diamond impregnated carbide matrix being formed by: (a) first, blending graphite particles with particles of an unsintered carbide matrix to produce a particle blend; (b) next, forming the particle blend into a green body of a desired shape; (c) next, sintering the green body; (d) plating the insert with a protective metal coating; and (e) thereafter, subjecting the sintered body containing graphite particles to temperature and pressure conditions sufficient to convert the graphite to diamond in-situ.

Claim 9

An improved earth boring bit of the type having rotary cutters defining a cutting structure for boring a hole, the cutters being mounted rotatably on a shank, the improvement comprising wear inserts on the cutting structure, the wear inserts comprising a diamond impregnated carbide containing dispersed diamond crystals, the crystals being formed via the in-situ conversion of graphite to diamond, the diamond impregnated carbide matrix being formed by: (a) first, blending graphite particles with particles of an unsintered carbide matrix to produce a particle blend; (b) next, forming the particle blend into a green body of a desired shape; (c) next, sintering the green body; (d) plating the insert with a protective metal coating; and (e) thereafter, subjecting the sintered body containing graphite particles to temperature and pressure conditions sufficient to convert the graphite to diamond in-situ.

Claim 10

An improved earth boring bit of the type having rotary cutters defining a cutting structure for boring a hole, the cutters being mounted rotatably on a shank, the improvement comprising wear inserts on the cutting structure, the wear inserts comprising: a diamond impregnated carbide matrix, the carbide being comprised of graphite particles which are first blended with particles of an unsintered carbide matrix, the unsintered carbide matrix being comprised of at least one metal carbide powder combined with a binder which includes at least one elemental powder known to be a diamond catalyst, the unsintered carbide matrix being first formed into a green body of a desired shape, the green body then being sintered and thereafter, the sintered body being subjected to temperature and pressure conditions sufficient to convert the graphite to diamond in-situ.

Claim 11

An improved earth boring bit of the type having rotary cutters defining a cutting structure for boring a hole, the cutters being mounted rotatably on a shank, the improvement comprising wear inserts on the cutting structure, the wear inserts comprising: a diamond impregnated carbide matrix, the carbide being comprised of graphite particles which are first blended with particles of an unsintered carbide matrix, the unsintered carbide matrix being comprised of at least one metal carbide powder combined with a binder which includes at least one elemental powder known to be a diamond catalyst, the unsintered carbide matrix being first formed into a green body of a desired shape, the green body then being sintered and thereafter, the sintered body being subjected to temperature and pressure conditions sufficient to convert the graphite to diamond in-situ.

Claim 12

The improved drill bit of claim 7, wherein the metal carbide powder is selected from the group consisting of W, Ti, Zr, Hf, V, Nb, Ta, Cr and Mo.

Claim 13

The improved drill bit of claim 8, wherein the elemental powder known to be a diamond catalyst is selected from the group consisting of elements from rows 3, 4, 5 or 6 of the periodic table known to be diamond catalysts.

Claim 14

The method of claim 9, wherein the elemental powder known to be a diamond catalyst is selected from the group consisting of Ni, Co, Fe, Al, B and alloys thereof.

Claim 15

The method of claim 10, wherein the particle size of the graphite particles used in forming the particle blend is in the range from about .2-1000 microns.

Claim 16

The improved drill bit of claim 11, wherein the binder is present in the range from about 5 to 50% by volume, based on the total volume of the particle blend.

Claim 17

The improved drill bit of claim 12, wherein the green body is sintered at a temperature below about 1500 ° C and at a pressure below about 1000 psi.

Claim 18

The improved drill bit of claim 13, wherein the sintered body is subjected to a temperature of at least about 12000 C and a pressure of at least about 40 kilobars in an HPHT apparatus to convert the free carbon to diamond in-situ.

Claim 19

An improved earth boring bit of the type having rotary cutters defining a gage diameter of a hole being bored, the cutters being mounted rotatably on a shank, the improvement comprising wear inserts at the gage row of the cutters comprising a diamond impregnated carbide containing dispersed diamond crystals, the crystals being formed via the in-situ conversion of graphite to diamond.

Claim 20

An improved earth boring bit of the type having rotary cutters defining a gage diameter of a hole being bored, the cutters being mounted rotatably on a shank, the improvement comprising wear inserts at the gage row of the cutters comprising a diamond impregnated carbide containing dispersed diamond crystals, the crystals being formed via the in-situ conversion of graphite to diamond.

Claim 21

An improved earth boring bit of the type having rotatable cutters, the improvement comprising wear resistant inserts used as earth disintegrating teeth on each of the cutters, each wear resistant insert comprising a cemented tungsten carbide body containing dispersed diamond crystals which exhibit diamond-to-diamond bonding via the in-situ conversion of graphite particles to diamond in the cemented tungsten carbide body.

Claim 22

An improved earth boring bit of the type having rotatable cutters, the improvement comprising wear resistant inserts used as earth disintegrating teeth on each of the cutters, each wear resistant insert comprising a cemented tungsten carbide body containing dispersed diamond crystals which exhibit diamond-to-diamond bonding via the in-situ conversion of graphite particles to diamond in the cemented tungsten carbide body.