Methods of forming erosion-resistant composites, methods of using the same, and earth-boring tools utilizing the same in internal passageways

[0001] The invention generally relates to methods for forming wear-resistant materials, methods for using wear-resistant materials to form drilling tools having increased wear resistance, and drilling tools comprising wear-resistant material. More specifically, the invention relates to drilling tools and their components that are substantially resistant to erosion caused by fluid flow through the scrubbing channels, methods for forming such drilling tools, and methods for forming erosion-resistant materials for use in such tools.

[0002] Drilling tools are commonly used to form (eg, drill and ream) bore holes (referred to herein as "wells") in earth formations. Drilling tools include, for example, rotary drill bits, core drill bits, eccentric drill bits, double-centered drill bits, dilators, reamers and comminution devices. [0003] Earth type rotary drill bits have several configurations. One configuration is the cutting auger, which normally includes multiple blades or blades, each having a plurality of cutting elements arranged thereon. Another configuration is a drill with a tapered roller work tip, which normally includes three cones placed on the drill support arms that extend from the drill body, which can be formed, for example, from three head parts that are welded together to form the drill body . Each of the drill bits can be dependent on one head part of the drill. Each roller tapered tip is configured to rotate on a bearing shaft that extends radially inward and downward from the drill arm. The cones are normally formed of steel, but can also be formed of molecular matrix composite materials (e.g., ceramic-metal sinters such as sintered tungsten carbide). Cutting blades for cutting rock and other earth formations can be machine-made or otherwise formed in or on the outer surfaces of each cone. Alternatively, sockets are created in the outer surfaces of each cone, and inserts formed of hard, wear-resistant materials, in some cases coated with a highly abrasive material such as polycrystalline diamond, are mounted in the sockets to create cone cutting elements.

[0004] A rotary drilling tool may be placed in the wellbore so that the cutting structures are adjacent to and in contact with the earth formation to be drilled. When the drilling tool is rotated due to the longitudinal force applied to the drill pipe with jumpers, to which the rotary drilling tool is attached, the cutting structures remove the adjacent material of the formation.

[0005] It is known to apply wear-resistant materials, so-called "curing surfacing" materials, so that the surfaces of rotary drill bits entering the formations wear the drilling tools surfaces as little as possible by abrasion. For example, abrasion occurs on the above surfaces of the earth tool when these surfaces sink and move relative to the surface of the underground formation in the presence of particulate material (e.g., cuttings of the formation and detritus) carried by a conventional drilling mud. For example, hardfacing can be applied to cutting teeth on a drill cone with a tapered roller working tip, as well as to even the cone surfaces. Hardfacing can also be applied to the outer surfaces of the curved lower end or "end" of each bit arm, and other external surfaces of the drill tool that may enter the formation during drilling. Curing surfacing can also be applied to the cutting bit surfaces entering the formations.

[0006] During drilling, the drilling mud is pumped into the wellbore through a drill pipe with jumpers for the drilling tool. The drilling fluid passes through the inner longitudinal hole in the drilling tool and through other fluid channels or passages in the drilling tool, to the nozzles that direct the drilling mud from the drilling tool at substantially high speed. The nozzles can be directed to the cutting structures to remove rock debris and detritus from the cutting structures and to prevent the drill tool from clumping. Nozzles can also be directed through cutting structures and towards the bottom of the well to flush rock debris and detritus from the bottom of the well and through the ring between the drill pipe with jumpers and the housing (or exposed surfaces of the formation) in the well, which can improve the mechanical performance of the drilling tool and penetration level (ROP) of the drilling tool in the formation. [0007] It is known in the art to use flow nozzles to direct the drilling mud to the nozzle and from inside the drilling tool, in particular when it is desired to direct the drilling mud through the cones of the rotary drilling tool and towards the bottom of the well. Such flow nozzles may be formed separately from the bit body, and may be attached to the bit body (e.g., bit face or bit arm) by, for example, welding the flow nozzles to the bit body. The fluid path and channel is formed by the bit body to provide fluid communication between the inner longitudinal bore of the drilling tool and the scrubbing channel in the flow nozzle.

[0008] When the drilling mud flows through the flow nozzles and / or the mud channels in the drilling tool, the drilling mud erodes the internal surfaces of the flow nozzle and the bit body. Such erosion can be generally more severe in places where the direction of fluid flow changes, since the drilling fluid impacts the internal surfaces of the flow nozzle or bit body at substantially smaller angles. Erosion may be the result of holes that pass completely through the walls of the flow nozzle or bit body, allowing the drilling fluid to flow out of the flow nozzle or bit body before passing through the nozzle, which ultimately leads to failure of the designed hydraulic system of the drilling tool. When the hydraulic system of the drilling tool fails, the level of penetration decreases and the drilling tool becomes more susceptible to "clumping." Finally, the drilling tool may fail and must be replaced.

[0009] US 2005/146086, to which the independent claims are characterized, discloses the use of gradient layers and stress modifiers in highly hard constructions. US-5574957 discloses a method of reinforcing an object in an enclosure or outer material layer. EP-1621272 discloses a method of preparing a weld layer for an adhesive. US4228214 discloses a flexible two-layer sheet. WO 2009/018427 discloses methods for forming earth drilling tools. US-5508334 discloses a gelatinous thermoplastic elastomer and articles.

[0010] With reference to the invention, an intermediate structure is formed during the production of an earth tool, as claimed in claim 1. In a further aspect of the invention, there is provided a method of applying hard surfacing to the surface of a drilling tool as claimed in claim 7.

[0011] Disclosed herein are multiparticulates used in forming a hardfacing layer on the tool surface. The layers include a first layer that includes a first polymeric material and the first plurality of particles dispersed in the first polymeric material. The second layer covers at least a portion of the surface of the first layer and includes a second polymeric material and a second plurality of particles dispersed in the second polymeric material.

[0012] Disclosed are intermediate structures formed during the manufacture of the earth tool that include the earth tool body, a first material layer disposed on at least a portion of the surface of the body, and a second material layer disposed on at least a portion of the first material layer on the side opposite the body. The first layer of material comprises a plurality of hard particles dispersed in the first polymeric material, and the second layer of material comprises a plurality of matrix metal particles dispersed in the second polymeric material.

[0013] Methods of applying hardfacing to the surface of an earth tool are disclosed. Many hard particles, many metal matrix particles, polymer material, and liquid solvent can be mixed together to form a paste that can be spread on the surface of the substrate to form a paste layer. Liquid solvent may be removed from the paste layer to form at least a substantially solid layer that includes a plurality of hard particles, a plurality of matrix metal particles, and a polymeric material. The layer can be removed from the surface of the substrate and applied to the surface of the earth body of the tool. The tool body can be heated to a first temperature while a layer is on the tool body to remove polymer material from the tool earth body. The earth body of the tool can then be heated to a second temperature higher than the first temperature to sinter at least a plurality of matrix metal particles to form a layer of hardfacing material on the surface of the earth body of the tool that includes a plurality of hard particles dispersed in the metal phase of the matrix formed of many metal matrix particles.

[0014] Disclosed herein are methods of applying hardfacing on the surface of an earth tool. A first material that includes a plurality of hard particles and a first polymeric material can be applied to the surface of the earth body of the tool. A second material layer that includes a plurality of matrix metal particles and a second polymeric material can be applied adjacent the first material layer on the side opposite the earth body of the tool. The tool body is heated to a first temperature while the first material layer and the second material layer are on the earth tool body to remove the first polymer material and the second polymer material from the earth tool body. The tool body can then be heated to a second temperature higher than the first temperature to sinter at least a plurality of matrix metal particles to form a layer of hardfacing material on the surface of the tool body that includes a plurality of hard particles dispersed in a metal matrix phase formed from a plurality of metal matrix particles .

[0015] While the specification ends with claims in particular indicating and clearly stating what is considered the invention, the various features and advantages of the invention can be readily determined from the following description of the invention, read in conjunction with the accompanying drawings, in which:

FIG. 1 depicts an embodiment of an earth rotary drill according to an embodiment of the invention;

FIG. 2 is a simplified cross-sectional view of the embodiment of the multiparticulate layer that can be used to form a hardfacing layer on the surface of a drilling tool, such as the earth rotary drilling tool shown in FIG. 1;

FIG. 3 is a simplified cross-sectional view of an embodiment of a multiparticulate layer that can be used to create a hardfacing layer on the surface of a drilling tool;

FIG. 4 is a partial cross-sectional view of the earth body of the tool showing the multiparticulate layer as that shown in FIG. 2 on the surface in a flushing channel extending through the body of the drilling tool;

FIG. 5 is a partial cross-sectional view of the ground body portion of the tool shown in FIG. 4 showing a layer of curing material formed of a multiparticulate;

FIG. 6A is an axonometric view of an embodiment of a flow nozzle according to the invention that can be used with a drilling rig such as the rotary drill rig shown in FIG. 1;

FIG. 6B is a side view of the flow nozzle shown in FIG. 6A;

FIG. 6C is a front view of the flow nozzle shown in FIG. 6A and 6B;

FIG. 6D is a longitudinal cross-sectional view of the flow nozzle shown in FIG. 6A-6C along the hatching line of section 6D-6D shown on

FIG. 6C;

tool tool

FIG. 6E is a cross-sectional view of the flow nozzle shown in FIG. 6A-6D along the hatching line of section 6E-6E shown on

FIG. 6C;

FIG. 6F is a longitudinal cross-sectional view (such as in FIG. 6D) of the flow nozzle shown in FIG. 6A-6E illustrating the erosion of the inner wall of the flow nozzle that may occur during drilling due to the flow of the drilling mud through the flow nozzle;

FIG. 7A is an axonometric view of another embodiment of a flow nozzle according to the invention that can be used with drilling tools such as the rotary drilling tools shown in FIG. 1;

FIG. 7B is a front view of the flow nozzle shown in FIG. 7A;

FIG. 7C is a longitudinal cross-sectional view of the flow nozzle shown in FIG. 7A-7B along the hatching line of section 7C-7C shown on

FIG. 7B; and

FIG. 7D is a cross-sectional view of the flow nozzle shown in FIG. 7A-7C along the hatching line of section 7D-7D shown on

FIG. 7B.

[0016] As used herein, the term "abrasion" refers to a third body wear mechanism that includes two surfaces of solid materials abrasion with each other with the material of solid particles between them.

[0017] As used herein, the term "erosion" refers to a second body wear mechanism that occurs when the particulate material, fluid, or fluid carrying the particulate material hits solid surfaces.

[0018] The term "fluid" as used herein includes substances consisting solely of liquids, as well as substances containing particulate material suspended in a fluid, and includes a conventional drilling fluid (or clay mud) that may contain particulate material such as additives , as well as cut off formations and detritus suspended in liquid.

[0019] The term "hardfacing" as used herein means any material or mass of material that is applied to the surface of a separately formed body and which is more resistant to wear (abrasion and / or erosive wear) relative to the material of the separately formed body on its surface.

[0020] The illustrations herein are not, in some cases, real views of specific earth tools, flow nozzle, or flushing channel, but are merely simplified representations that are used to describe the invention. In addition, common elements in the figures may have the same reference numerals. [0021] The invention includes embodiments of methods for surfacing the inner surfaces of tools such as a drilling tool 1 on intermediate structures formed during such methods, and on drilling tools created using such methods. Generally, the methods include mixing together the polymer material and particles that will ultimately be used to form a hardfacing material, applying the mixture to the surface of earth boring rigs such as shown in FIG.

tools, and heating the mixture on an earth boring tool to remove the polymer material and sinter the particles previously mixed with it to form a layer of hardfacing material on the surface of the tool. [0022] FIG. 1 is a perspective side view illustrating an example of an earth tool to which hardfacing may be applied in accordance with embodiments of the invention. The ground tool of FIG. 1 is a rotary drilling tool of the type with movable cutting elements, wherein such drills are also known in the art as "rotary cone" drills as described above, due to the general conical shape of the cutting elements used in many such drills. An embodiment of the drilling tool 10 shown in FIG. 1 includes three end portions 12 that are welded together to form drill bit body 14 of drilling tool 10, and such an arrangement is known to those skilled in the art. Only the two front parts 12 are visible in FIG. 1. The bit body 14 may include a mandrel 22 or other means for securing the drill tool 10 to the drill pipe with jumpers or bottom assembly (not shown). In some embodiments, the mandrel 22 may be shaped to meet industry standards for threaded connections for mandrels, such as those announced by the American Petroleum Institute (API).

[0023] The bit arm 16 extends downward from each face part 12 of the drilling tool 10. Each bit arm 16 can be integrally formed with the respective face part 12 on which it depends. As shown in FIG. 1, at least one hardfacing material 20 and inserts 21 can be used to protect the outer surfaces of the arms of drill bit 16 against wear. By way of example and not limitation, curing surfacing material 20 can be rotatably applied to the front surfaces of the bit arms 16 and to the lower surfaces or "rear" at the bottom ends 18 of the bit arms 16, and the inserts 21 may be located in or on the radially outermost surfaces of the bit arms 16 as shown in FIG. 1. The hardfacing material 20 and the liners 21 may contain materials that are generally more wear resistant relative to the material of the arms of the bit 16 on their surfaces. In additional embodiments, the outer surfaces of the arms of the bit 16 may only contain inserts 21 and not contain curing material 20, or only contain curing material 20 without inserts 21. In yet further embodiments, the outer surfaces of the arms of the bit 16 may contain neither hardfacing material 20 nor inserts 21.

The rotary cutting element in the form of a rotary cone 40 can be rotatably mounted on a bearing shaft (not shown) which extends downwards and radially to the center from the lower end 18 of each drill arm 16 (relative to the longitudinal center line (not shown) of the drilling tool 10 and when the drilling tool 10 is facing the observer as shown in FIG. 1). The rotary cones 40 are rotatably mounted on bearing shafts such that when the drilling tool 10 is rotated at the bottom of the wellbore in an earth formation, the rotary cones 40 rotate and move over the formation below.

[0025] Each rotary cone 40 includes a plurality of cutting elements 32 that can be arranged in rows extending circumferentially around the rotary cone 40 to crush and separate the formation as the rotary cones 40 rotate and move through the formation at the bottom of the wellbore. In the embodiment shown in FIG. 1, cutting elements 32 include inserts that are pressed into respective recesses formed in the body of rotary cones 40. The inserts may contain substantially hard and abrasive material such as, for example, sintered tungsten carbide. In additional embodiments, the cutting elements 32 may include cutting teeth that are machined on or in the surface of rotary cones 40. Such cutting teeth may be coated with a hardfacing material (not shown), similar to a hardfacing material 20, which may include, for example, a composition comprising hard particles (e.g., tungsten carbide) dispersed in a metal material or matrix metal alloy (e.g. , alloys based on iron, cobalt or nickel).

[0026] Still referring to FIG. 1, drilling tool 10 includes three flow nozzles 36 (of which only two are visible in FIG. 1). In the embodiments shown in FIG. 1, the flow nozzles 36 are individual structures that are separately formed from the front parts 12 (and integrally with the arms 16 of the drill bit) of the drilling tool 10. The flow nozzles 36 are attached to the bit body 14 by, for example, welding the flow nozzles 36 to the bit body 14 after welding the face parts 12 together to form the bit body 14. In other embodiments, the flow nozzles 36 can be welded to one or more face parts 12 by welding the face parts 12 together to form the bit body 14. In yet further embodiments, the flow nozzles 36 may not be separately formed with the front parts 12 but, rather, they may be an integral part of the front part 12.

[0027] The drilling tool 10 includes internal mud channels (not shown in FIG. 1) that extend through the drilling tool 10. The mud channels may include, for example, an internal longitudinal bore (not shown), which may also be referred to as compensatory which extends at least partly through the spindle 22. The inner longitudinal bore may divide into many substantially smaller channels that lead from the longitudinal bore to the outside of the drilling tool 10. Some of the channels may lead to and extend through the flow nozzles 36.

[0028] As described above, during drilling, the drilling mud is pumped from the surface through a drill pipe with jumpers (not shown) and a drilling tool 10, to the bottom of the well. The drilling mud passes through the drilling channels in the drilling tool 10 and from the flow nozzles 36 towards the cones and / or exposed surfaces of the underground formation in the wellbore. Nozzles (not shown) can be placed in each flow nozzle 36. The nozzles may have internal geometries designed, dimensioned and shaped to at least partially determine the speed and direction of the drilling mud when the drilling mud passes through the nozzles and exits through the flow nozzles 36.

[0029] The invention includes embodiments of methods for applying hardfacing material on the inside and outside surfaces of drilling tools, such as the drilling tool 10 shown in FIG. 1, for intermediate structures created during such methods, and for drilling tools created using such methods. Broadly, the methods include mixing together the polymer material and particles that will ultimately be used to create the surfacing material, applying the compound to the surface of the earth tool, and heating the mixture on the earth tool to remove the polymer material and sinter the particles previously mixed in it to create a layer of hardfacing material on the surface of the tool.

[0030] With reference to FIG. 2, the multiparticulate layer 30 may be formed and applied to a surface of the earth tool such as, for example, the drill bit body 14 of the earth rotary drill bit 10. For example, the multiparticulum 30 may be applied to the inner surfaces of the bit body 14 in fluid scrubbing channels extending therein and, in particular, to areas of the inner surfaces that are prone to erosion caused by the flow of drilling fluid through the scrubbing channels. For the purposes of notification, "susceptible to erosion" areas caused by the flow of a drilling mud through a flow nozzle or a mud channel can be considered areas of a flow nozzle, drilling tool or other earth tool that will eventually be eroded by the drilling mud, when a conventional drilling fluid flows through a flow nozzle or mud channel at a constant conventional flow rate and fluid pressure for a period of time shorter by about five times than the average operating time, determined in operating hours, a drilling tool of a specific design or model or other earth tool having nozzles flow or flushing channel. In other words, if a conventional drilling fluid flows through a flow nozzle or a mud channel with a conventional flow rate and fluid pressure for a period of time that is about five times the average lifetime of a drilling tool of a particular design or model or other earth tool having flow nozzles or a mud channel, and the area of ​​the flow nozzle, drilling tool or other earth tool has eroded, this area for the purposes of this application can be considered as "susceptible to erosion" caused by the flow of a drilling mud through a flow nozzle or a mud channel. [0031] By way of example and not limitation, in some embodiments, the multiparticulate layer 30 may include a flexible dual molecule sheet as disclosed in US Patent No. 4,228,214 to Steigelman et al., Dated October 14, 1980.

[0032] As shown in FIG. 2, the multiparticulate layer 30 includes a first layer 32 and at least one additional second layer 34. The first layer 32 covers at least a portion of the surface 35 of the second layer 34. Each first layer 32 and second layer 34 comprise polymer material and a plurality of particles dispersed in the polymer material.

[0033] The polymeric material of the first layer 32 may have an identical composition, or at least substantially similar to the polymeric material of the second layer 34. In additional embodiments, the polymeric material of the first layer 32 may have a composition that is different from the composition of the polymeric material of the second layer 34. One or both of the polymeric materials of the first layer 32 and the polymeric material of the second layer 34 may comprise a thermoplastic and elastomeric material. The term "thermoplastic material" as used herein means and includes any material that exhibits a hardness value that decreases as the material temperature rises from about room temperature to about 93.3 ° C (200 ° F). The term "elastic" as used herein means and includes a material that, when subjected to tensile loading, undergoes more than longitudinal permanent permanent deformation (e.g., plastic) but longitudinal deformation prior to fracture. By way of example and not limitation, one or both polymers of the first layer 32 and the polymer of the second layer 34 may include at least one styrene-butadiene-styrene system, styrene-ethylene-butylene, styrene, styrene-divinyl-benzene, styrene-styrene-styrene, and styrene-ethylene-styrene. The thermoplastic elastomer may comprise a block copolymer material having at least one terminal block having a molecular weight between about 50,000 and about 150,000 grams per mole and at least one middle block having a molecular weight between about 5,000 and 25,000 grams per mole. In addition, the block copolymer material may have a glass transition temperature between about 130 ° C and about 200 ° C. In some embodiments, the at least one polymeric material of the first layer 32 and the polymeric material of the second layer 34 may be identical or at least substantially similar to those described in US Patent No. 5, 508,334, issued on April 16, 1996 to

Chen.

[0034] Still referring to FIG. 2, the particles in the first layer 32 may at least substantially contain hard particles. By way of example and not limitation, the particles in the first layer 32 may at least substantially contain particles containing a hard material such as diamond, regular boron nitride (the above two materials are also known in the art as "ultra-hard" and "super-abrasive" materials) boron carbide, regular nitride boron, boron carbide, aluminum nitride and carbides or borides of the group consisting of W, Ti, Mo, Nb, V, Hf, Zr, Si, Ta, and Cr.

[0035] The particles in the second layer 34 may at least substantially include metal-containing particles or a metal alloy for forming the matrix phase of the hardfacing material. By way of example and not limitation, the particles in the second layer 34 may at least substantially contain cobalt-containing particles, a cobalt-based alloy, iron, an iron-based alloy, a nickel, a nickel-based alloy, a cobalt and nickel-based alloy, an iron-nickel-based alloy , iron and cobalt based alloy, aluminum based alloy, copper based alloy, magnesium based alloy or titanium based alloy.

[0036] In additional embodiments, the particles in the first layer 32 may at least consist essentially of metal-containing particles or a metal alloy for forming the matrix phase of the surfacing material, and the particles in the second layer 34 may at least essentially consist of hard particles. In further embodiments, both the first layer 32 and the second layer 34 may comprise hard particles and metal or metal alloy containing particles.

[0037] In some embodiments, one or both, the first layer 32 and the second layer 34 of the multiparticulum 30 may comprise a layer of at least substantially solid material. For example, at least the second layer 34 may include a layer of at least substantially solid material. Additionally, in some embodiments, one or both, the first layer 32 and the second layer 34 of the multiparticulates 30 may comprise a paste. By way of example and not limitation, the second layer 34 may include a layer of at least substantially solid material, and the first layer 32 may include a paste that is disposed on and at least substantially covers the surface of the second layer 34 as shown in FIG.

2. FIG. 3 illustrates an additional embodiment of the multiparticulate layer 30 'of the invention, which includes a first layer 32' and a second layer 34. The multiparticulate layer 30 'is substantially similar to the multiparticulate layer 30 of FIG. 2, except that the first layer 32 'of the multiparticulate layer 30' comprises a solid layer similar to the second layer 34.

[0038] FIG. 4 shows the multiparticulate layer 30 of FIG. 2 applied to the surface 15 of the bit body 14 of the drilling tool 10 in which it is desirable to apply a hardfacing material such that the paste of the first layer 32 is sandwiched between the surface of the earth tool and the second layer 34 of the multiparticulate layer 30. In other words, the paste of the first layer 32 may be placed on at least a portion of the surface 15 of the drill bit body 14 of the drilling tool 10, and the second layer 34 may be placed on at least a portion of the first layer 32 on its side opposite the surface 15 of the earth body of the rotary drill bit 10 . The paste can be used to hold or bond the multiparticulum 30 to the surface of the earth tool until the earth tool and the multiparticulate 30 are heated to form a curing material from the multiparticulate layer 30, as further described in detail below. In some embodiments, the surface 15 of the body 14 of the earth turntable 10 may include a surface 15 in a mud channel 26 extending at least partially through the body 14 of the earth turntable 10, as shown in FIG. 4.

[0039] FIG. 5 is a partial cross-sectional view of the part of the bit body 14 of the earth-boring bit 10 shown in FIG. 4, further showing a layer of curing material 28 formed with the multiparticulate layer 30, 30 'or paste, as described above, on the surface 15 of the bit body 14 in the flushing channel 26. By way of example and not limitation, the hardfacing material 28 may comprise a composite material having a substantially hard first phase distributed in the second continuous metal or metal matrix phase. [0040] By way of example and not limitation, the first phase may contain hard materials such as diamond, boron carbide, regular boron nitride, aluminum nitride and carbides or borides of the group consisting of W, Ti, Mo, Nb, V, Hf, Zr, Si , Ta and Cr, and the matrix metal phase may include cobalt, cobalt-based alloy, iron, iron-based alloy, nickel, nickel-based alloy, cobalt-nickel-based alloy, iron-nickel-based alloys, alloy based iron and cobalt, aluminum-based alloy, a copper-based alloy, a magnesium-based alloy or a titanium-based alloy. In some embodiments, the first step may comprise a plurality of discrete regions or particles dispersed in the metal or metal alloy matrix phase. [0041] In some embodiments, the hardfacing material 28 may include the hardfacing composition as described in US Patent No. 6,248,149, dated June 19, 2001, and titled "Hardfacing Composition for Earth-Boring Bits Using Macrocrystalline Tungsten Carbide and Spherical Cast Carbide," or US Patent No. 7,343,990, dated March 18, 2008 and titled "Rotary Rock Bit With Hardfacing to Reduce Cone Erosion. "[0042] In some embodiments, the multiparticulates 30, 30 '(FIG. 2 and 3) used to create hardfacing material 28 can be formed in place on surface 15 (FIG. 4) of drill bit body 14 of drilling tool 10, while in other embodiments, the multiparticulates 30, 30 'can be separately formed and sequentially applied to a surface 15. Methods for forming the 30 and 30 'multiparticulates will be described in detail below.

[0043] The particles that will be used to form the hardfacing material 28 (FIG. 5) (i.e., hard particles and / or particles comprising a metal or matrix metal alloy material) may be mixed with one or more polymeric material and one or more more solvent to form a paste or suspension.

[0044] One or more polymeric materials may comprise a thermoplastic and elastomeric polymeric material as described above. For example, at least one of the styrene-butadiene-styrene systems, styrene-ethylene-butylenestyrene, styrene-divinylbenzene, styrene-isoprene-styrene, and styrene-ethylene-styrene can be mixed with particles and a solvent to form a paste or suspension.

[0045] The suspension may contain one or more plasticizers added to the polymer material to selectively modify the deformation of the polymer material. The plasticizer may be or include light oils (e.g., paraffinic and naphthenic petroleum oil), polybutene (polybutylene), cyclobutene, polyethylene (e.g. polyethylene glycol), polypropene, fatty acid ester or fatty acid amide.

[0046] The solvent may contain any substance in which the polymer material can at least partially dissolve. For example, the solvent may contain methyl ethyl ketone, alcohols, toluene, hexane, heptane, propyl acetate, and trichlorethylene or other conventional solvent.

[0047] The suspension may also contain one or more stabilizers to assist in the suspension of one or more polymeric material in a solvent. Suitable stabilizers for various combinations of polymers with solvents are known to those skilled in the art.

[0048] After the paste or suspension is formed, the paste or suspension can be applied as a substantially thin layer to the surface of the substrate using, for example, a casting process. The solvent may then be allowed to evaporate from the paste or slurry to form a substantially solid layer of polymeric material in which hard particles and / or particles containing metal material or matrix metal alloy are placed. For example, the paste or suspension may be heated on a substantially flat surface of the dried substrate after casting to a temperature sufficient to evaporate the solvent from the paste or suspension. The paste or suspension can be dried in a vacuum to reduce drying time and eliminate fumes generated during the drying process.

[0049] To form the multiparticulate layer 30 shown in FIG. 2, the slurry may be formed by mixing particles containing a metal material or matrix metal alloy with one or more polymeric material and one or more solvent, and the slurry may be cast and dried to form the second layer 34 of the multiparticulum 30. After forming the second layer 34, the paste can be formed by mixing hard particles with one or more polymeric material and one or more solvent, and the paste can be applied to the main surface of the second layer 34 so that the main surface of the second layer 34 is at least substantially coated paste to form the first layer 32 of the multiparticulates 30.

[0050] To form the multiparticulate layer 30 'shown in FIG. 3, the first suspension may be formed by mixing particles containing a metal material or matrix metal alloy with one or more polymeric material and one or more solvent, and the first suspension may be cast and dried to form the second layer 34 of the 30 'multiparticulate layer as described above. After forming the second layer 34, the second suspension may be formed by mixing hard particles with one or more polymeric material and one or more solvent, and the second suspension may be cast and dried on the main surface of the second layer 34 to form the first layer 32 'of the multiparticulate layer thirty'. In other embodiments, the first layer 32 'and the second layer 34 may be separately formed in a separate casting and drying process and sequentially folded together to form the multiparticulate layer 30' by, for example, placing the first layer 32 'and the second layer 34 adjacent to each other in turn and moving them together through the pressure rollers.

[0051] In additional embodiments, a paste formed by mixing hard particles and particles containing a metal material or matrix metal alloy with one or more polymeric materials and one or more solvent (and, optionally, plasticizers, etc.) can be applied directly to the surface 15 of the bit body 14 of the drilling tool 10 to which the surfacing material 28 is to be applied (FIG. 5), and the hardfacing material 28 may be formed from a paste as described in turn herein.

[0052] After the multiparticulate layer 30, 30 'has been formed, the multiparticulate layer 30, 30' can be applied to the surface 15 of the bit body 14 of drilling tool 10 onto which the hardfacing material 28 is applied (if the multiparticulate layer 30, 30 'has not been formed in place on the surface 15 of the body 14). If the macromolecular layer 30, 30 'does not itself stick to the surface 15 of the body 14, the adhesive may be placed between the macromolecular layer 30, 30' and the surface 15 of the body 14 to glue the multiparticulate layer 30, 30 'to the surface 15 of the body 14. The multiparticulate layer 30, 30 'can be cut or otherwise formed to have an appropriate shape matching the surface 15 to which it is applied. For example, the multiparticulate layer 30, 30 'may be cut or otherwise formed to have a shape matched to the inner surface of the earth tool in the scrubbing channel extending therethrough. [0053] The body 14 of the earth rotary drill bit 10, together with the multiparticulate layer 30, 30 'or paste on one or more surfaces 15, may then be heated in an oven to form curing material 28 on the surface 15 of the multiparticle body 14 from the multiparticulate layer 30, 30 'or paste. After heating the 30, 30 'multiplayer or paste to temperatures between about 150 ° C and about 500 ° C, the organic materials in the 30, 30' multiparticulate or paste can oxidize and / or decompose, leaving inorganic components of the multiparticulate 30, 30 'or paste on the surface 15 of the body 14. For example, the multiparticulate layer 30, 30 'or paste may be heated at a rate of about 2 ° C per minute to a temperature of about 450 ° C to cause oxidation and / or degradation of organic materials (including polymeric materials) in the multiparticulate layer 30, 30' or paste.

[0054] After heating the multiparticulum 30, 30 'or paste for oxidation and / or decomposition of organic materials therein, the remaining inorganic multiparticulates 30, 30' or paste may further be heated to a substantially higher sintering temperature to sinter inorganic components and form hard surfacing material from them 28. For example, other inorganic multiparticulates 30, 30 'or pastes may further be heated at a rate of about 15 ° C per minute to a sintering temperature of about 1150 ° C. The sintering temperature may be close to the melting point of the metal material or metal alloy matrix matrix particles in the 30, 30 'multiparticulate or paste. For example, the sintering temperature may be slightly below, slightly above, or equal to the melting point of the metal material or matrix metal alloy.

[0055] The volatilization and / or decomposition process as well as the sintering process may be carried out under reduced pressure (e.g. in a vacuum oven), in an inert atmosphere (e.g., nitrogen, argon, helium or other at least substantially inert gas) or in a reducing atmosphere (e.g. hydrogen).

[0056] During the sintering process, at least the metal or metal alloy containing particles can concentrate and coagulate to form at least a substantially solid metal or metal alloy matrix phase in which the discontinuous hard phase formed from the hard particles is distributed. In other words, during sintering, hard particles can nestle in the metal layer material or matrix metal alloy formed from particles containing the metal material or matrix metal alloy. During the sintering process, the metal material or matrix metal alloy in the second layer 34 of the multiparticulates 30, 30 'can be fused into the first layer 32, 32' between its hard particles. When the body 14 of the rotary earth drill bit 10 is cooled, the metal material or matrix metal alloy joins the surface 15 of the body 14 and holds the hard particles in place on the surface 15 of the body 14.

[0057] In some embodiments, the multiparticulate layer 30, 30 'or paste may have an average thickness and a composition that, after sintering, allows obtaining a layer of hardfacing material 28 formed on the surface 15 of the earth body 14 of an average thickness between about 1 , 25 millimeter (0.05 inch) and about 12 millimeter (0.5 inch).

[0058] As described above, embodiments of the methods of the invention can be used to apply hardfacing material to the surfaces of drilling tools in the flushing channels extending therein at least partially. Such scrubbing channels may extend, for example, through the earth drill bit body and / or through the flow nozzle on the earth drill bit body. FIG. 6A-6F show an example of a flow nozzle 36 on which curing surfacing material 28 may be applied in accordance with embodiments of the invention. FIG. 6A is an isometric view of the flow nozzle 36, FIG. 6B is a side view of the flow nozzle 36, and FIG. 6C is a front view of the flow nozzle 36.

[0059] With reference to FIG. 6A, flow nozzle 36 includes a nozzle body 38, which may include metal or a metal alloy such as, for example, steel. As shown in FIG. 6D, which is a longitudinal cross-sectional view of the flow nozzle 36 along the dashed line 6D-6D shown in FIG. 6C, the flushing channel 26 extends through the nozzle body 38 of the flow nozzle 36 from the inlet 42 to the outlet 44. Drilling mud flows during drilling through the mud channel 26 from the inlet 42 to the outlet 44. The annular recesses 48 or other geometric elements (e.g., thread) can be machined or otherwise in the internal walls 39 of the nozzle body 38 in the mud channel 26 at outlet 44, to place and attach the nozzle and other associated seals (e.g., seals) and retaining rings.

[0060] Again with reference to FIG. 6A, the hardfacing material 28 can be applied to one or both of the rotatable front outer edge 50 and the rotatable rear outer edge 52 of the nozzle body 38. In addition, the hardfacing material 28 can be applied to the outer surfaces of the nozzle body 38 of the flow nozzle 36 on the areas, which are near or adjacent to interior areas of wall 39 (FIG. 6D) of the nozzle body 38, which are prone to erosion caused by the flow of drilling fluid through the flow nozzle 36.

[0061] With reference to FIG. 6D, the first portion 41A of the flushing channel 26 extends through the flow nozzle 36 in a first direction from the inlet 42 radially outward and downward (relative to the longitudinal center line of the drilling tool 10 when the flow nozzle 36 is attached to the drilling tool 10 and the drilling tool 10 is positioned relative to observer as shown in FIG. 1). The first portion 41A of the flushing channel 26 passes into the second portion 41 B of the flushing channel 26, which extends generally downward to the outlet 44. In the embodiment shown in FIG. 6A-6E, the first portion 41A of the flushing channel 26 is directed at an obtuse angle (i.e. between 90 ° and 180 °) relative to the second portion 41B of the flushing channel 26. In this configuration, when the drilling mud passes from the first part 41A to the second part 41 B of the mud channel 26, the drilling mud may strike the radially outwardly directed areas of the inner walls 39 of the nozzle body 38 in the second part 41 B at an acute angle of less than ninety degrees (90 °). As a result, the radially outer regions of the inner walls 39 of the nozzle body 38 in the second portion 41 B of the mud channel 26 may be more susceptible to erosion caused by the passage of the drilling mud through the mud channel 26 relative to other areas of the inner walls 39 of the nozzle body 38.

[0062] To limit damage to the flow nozzle 36 caused by erosion, a substantially thick layer of hardfacing material 28 'may be applied to the outer surfaces of the nozzle body 38 of the flow nozzle 36 that are adjacent to the inner walls 39 of the nozzle body 38 that are susceptible to erosion as shown in FIG. 6A- 6E. The substantially thick layer of hardfacing material 28 'may be formed in the form of an elongated strip extending downwards and covering radially the outer areas of the outer surface of the nozzle body 38 of the flow nozzle 36 (relative to the longitudinal center line of the drilling tool 10 (FIG. 1)) as best illustrated in FIG. 6A and 6C.

[0063] Using the surfacing material 28 'to limit damage to the flow nozzle 36 caused by erosion of the inner walls 39 of the nozzle body 38, it may be desirable to shape the substantially thick layer of surfacing material 28' to have a thickness that is greater than the thickness of the material hardfacing 28 used to prevent or reduce abrasion of the outer surfaces of the flow nozzle 36, such as hardfacing material 28 applied to the rotatable front and rear outer edges 50, 52 of the flow nozzle 36. By way of example and not limitation, a substantially thick layer of curing surfacing material 28 'may have an average thickness greater than about 5.0 millimeters (greater than about 0.2 inches), and curing surfacing material applied to the rotatable front and rear outer edges 50, 52 of the nozzle Flow 36 may have an average thickness less than about 4.5 millimeters (less than about 0.18 inches). As one particular non-limiting example, a substantially thick layer of curing surfacing material 28 'may have an average thickness between about 6.9 millimeters (about 0.27 inches) and about 8.2 millimeters (about 0.32 inches), and curing surfacing material 28 applied to the rotatable front and rear outer edges 50, 52 of the flow nozzle 36 may have an average thickness between about 0.8 millimeters (about 0.03 inches) and about 1.6 millimeters (about 0.06 inches).

[0064] In some embodiments, it may be desirable to shape the outer surface of the substantially thick layer of hardfacing material 28 'and the outer surface of the hardfacing material 28 applied to the rotatable front and rear outer edges 50, 52 of the flow nozzle 36 to be substantially the same in the plane as shown in FIG. 6A. To allow the outer surface of the hardfacing material 28 'and the hardfacing material 28 to align, the layer of hardfacing material 28' can be at least partially inserted in a recess 56 provided on the outer surface of the nozzle body 38 of the flow nozzle as shown in FIG. 6A, 6C, 6D, and 6E. With reference to FIG. 6D and 6E, in some embodiments, the recess 56 may be shaped as a groove that extends downward along the outer surface of the nozzle body 38. As a non-limiting example, the recess 56 may extend to the outer surface of the nozzle body 38 to a depth of between about 5. , 0 millimeters (about 0.20 inches) and about

13.0 millimeters (about 0.50 inches). More specifically, the recess 56 may extend to the outer surface of the nozzle body 38 to a depth of between about 6.1 millimeters (about 0.24 inches) and about 6.6 millimeters (about 0.26 inches).

[0065] FIG. 6F is a longitudinal cross-sectional view of the flow nozzle 36 similar to FIG. 6D, illustrating the erosion of the inner walls 39 of the nozzle body 38 of the flow nozzle 36 that may occur after the flow of drilling fluid through the flow nozzle 36 for a period of time during drilling. As shown in FIG. 6F, the inner walls 39 of the nozzle body 38 in the scrubbing channel 26 can erode until a substantially thick layer of curing surfacing material 28 'is exposed in the scrubbing channel 26. Curing surfacing material 28' can wear at a certain rate by erosion, which is lower than the rate wherein the material of the nozzle body 38 of the flow nozzle 36 is worn through erosion. Thus, the hardfacing material 28 'may prevent complete erosion through the drilling mud of the flow nozzle wall 36 from inside the flushing channel 26 as fast as in prior art flow nozzles, thereby allowing the embodiments of the flow nozzles 36 of the invention to function properly for longer periods of time and for the life of the drill bit 10.

[0066] In some embodiments, the hardfacing material 28 and the hardfacing material 28 'may have identical or similar compositions. In other embodiments, however, the composition of the hardfacing material 28 may differ from the composition of the hardfacing material 28 '. For example, in the embodiment described above with reference to FIG. 6A-6F, the hardfacing material 28 applied to the rotatable front and rear outer edges 50, 52 of the flow nozzle 36 can be primarily intended to reduce wear caused by abrasion, while at least a portion of the hardfacing material 28 'can be mainly intended to reduce wear caused by through erosion. Abrasion and erosion are two different wear mechanisms, and some compositions have better wear resistance, while other compositions have better resistance to erosion. Thus, the hardfacing material 28 'may have a composition that exhibits increased resistance to erosion relative to the hardfacing material 28, while the hardfacing material 28 may have a composition that exhibits increased abrasion resistance relative to the hardfacing material 28' in some embodiments of the invention .

[0067] With reference to FIG. 6E, in some embodiments, a substantially thick layer of curing surfacing material 28 'optionally may include a multi-layer structure having different layers that exhibit one or more distinctive physical properties. By way of example and not limitation, a substantially thick layer of hardfacing material 28 'may include a radially inner first layer 28A' having a composition with special properties such as to exhibit increased erosion resistance, and a radially outer second layer 28B 'having composition with special properties to have a composition increased abrasion resistance. In other words, the first layer 28A 'may exhibit an erosion resistance that is greater than the erosion resistance exhibited by the second layer 28B', and the second layer 28B 'may exhibit an abrasion resistance that is greater than the abrasion resistance that the first layer exhibits 28A '. As one non-limiting particular example, the first layer 28A 'of hardfacing material 28' may substantially fill in a recess 56 formed in the outer surface of the nozzle body 38 of the flow nozzle 36, and the second layer 28B 'of hardfacing material 28' may have a composition identical to the hardfacing material 28 applied to the rotary front and rear outer edges 50, 52 of the flow nozzle 36. In addition, the second layer 28B 'of hardfacing material 28' may be integrally formed with the hardfacing material 28 applied to the rotatable front and rear outer edges 50, 52 of the flow nozzle 36.

[0068] FIG. 7A-7D show another embodiment of a flow nozzle 66 having surfaces on which curing surfacing material may be applied in accordance with embodiments of the invention. FIG. 7A is an axonometric view of the flow nozzle 66 and FIG. 7B is a front view of the flow nozzle 66. FIG. 7C is a longitudinal cross-sectional view of the flow nozzle 66 along the dashed line 7C-7C in FIG. 7B, and FIG. 7D is a cross-sectional view of the flow nozzle 66 along the dashed line 7D-7D of FIG. 7B.

<td>[0069] W</td><td>regards</td><td>down</td><td>FIG.</td><td>7A, flow nozzle</td><td> 66</td>

<td>It includes</td><td>nozzle body</td><td> 68,</td><td>which</td><td>is generally similar</td><td>down</td>

<td>described</td><td colspan="2">above the body</td><td>nozzle</td><td>38 flow nozzle</td><td> 36</td>

shown in FIG. 6A, and includes a flushing channel 26 that extends through the nozzle body 68 of the flow nozzle 66 from the inlet 42 to the outlet 44 (FIG. 7C). In addition, curing surfacing material 28 may be applied to the rotatable front and rear outer edges 72, 74 of the flow nozzle 66. The nozzle body 68 of the flow nozzle 66, however, may not include a recess 56 (FIG. 6A), and the flow nozzle 66 may include a plurality of wear-resistant inserts 70 instead of a substantially thick layer of curing material 28 'as described above with respect to the flow nozzle 36. Wear-resistant inserts 70 can be efficient in reducing abrasive wear on the outer surface nozzle body 68, flow nozzle 66. Wear-resistant inserts 70, however, may be substantially less efficient (relative to the hardener surfacing layer 28 'described above (FIG. 6D) while limiting the erosive wear of the nozzle body 68 caused by the drilling fluid flow through the mud channel 26.

[0070] With reference to FIG. 7C, the hardfacing material 28 can be applied to at least a portion of the inner wall 80 of the nozzle body 68 in the flushing channel 26. The hardfacing material 28 can be used to reduce the erosive wear of the nozzle body 68 due to the flow of the drilling mud through the flushing channel 26. In some embodiments, curing surfacing material 28 can be applied to and cover substantially all internal walls 80 of the nozzle body 68 of the flow nozzle 66 that are exposed in the flushing channel 26 after attachment of the nozzle (not shown). In other embodiments, the hardfacing material 28 can only be applied to areas of the inner walls 80 that are prone to erosion, such as areas of the inner walls 80 that the drilling mud will strike on the inner walls 80 at sharp angles when the drilling mud is pumped through flow nozzle 66.

[0071] By way of example and not limitation, a layer of curing material 28 applied to the inner walls 80 of the nozzle body 68 may have an average thickness between about 1.25 millimeters (0.05 inches) and about 20 millimeters (0.8 inches). The curing material 28 may have a composition with special properties so that it exhibits increased resistance to erosion.

[0072] In additional embodiments, the flow nozzles may comprise both a substantially thick layer of curing material 28 'as disclosed above with reference to FIG. 6A-6F and hardfacing material 28 applied to at least a portion of the inner wall of the body in the flushing channel as disclosed above with reference to FIG. 7A-7D.

[0073] Although the flow nozzle 36 previously described with reference to FIG. 6A-6F and the flow nozzle 66 previously described with reference to FIG. 7A-7D are shown as comprising separate bodies that are attached to the bit body (or one bit arm or part of the bit body head) by, for example, welding, additional embodiments of the invention may include flow nozzles that are integrally formed of (and are an integral part of the bit body (or one bit of the bit or part of the bit head), as well as drilling tools having such integrally formed flow nozzles or mud channels.

[0074] Additional examples to the embodiments are described below.

[0075] Embodiment 1: a multiparticulate layer for use in forming a hardfacing layer on the surface of a tool, comprising: a first layer comprising: a first polymeric material; and the first plurality of particles dispersed in the first polymeric material; and a second layer covering at least a portion of the surface of the first layer, the second layer comprising: a second polymeric material; and the second many particles dispersed in the second polymeric material. [0076] Embodiment 2: the multiparticulate layer of Embodiment 1 wherein the first polymeric material and the second polymeric material have at least substantially similar compositions.

[0077] Embodiment 3: the multiparticulate layer of Embodiment 1 wherein at least one of the first polymeric material and the second polymeric material comprises a thermoplastic and elastomeric material.

Embodiment 4: the multiparticulate layer according to Embodiment 1 or Embodiment 2 wherein at least one of the first polymeric material and the second polymeric material comprises at least one of the styrene-butadiene-styrene, styrene-ethylene-butylene-styrene, styrene systems - divinylbenzene, styrene-isoprene-styrene, and styreneethylene-styrene.

[0079] Embodiment 5: the multiparticulate layer according to any of Embodiments 1 to 4, wherein at least one of the first polymeric material and the second polymeric material further comprises at least one of oil, polybutene, cyclobutane, polyethylene, polyethylene glycol, and polypropylene.

[0080] Embodiment 6: the multiparticulates according to any one of Embodiments 1 to 5, wherein the first plurality of particles at least essentially consist of hard particles.

[0081] Embodiment 7: the multiparticulates according to Embodiments 1 to 6, wherein the second plural of the particles consists of at least substantially metal-containing particles or a metal alloy.

[0082] Embodiment 8: the multiparticulate layer according to any of Embodiments 1 to 7, wherein at least one of the first polymeric material and the second polymeric material comprises a thermoplastic and elastomeric material.

[0083] Embodiment 9: the multiparticulate layer according to any of Embodiments 1 to 8, wherein at least one of the first and second layers comprises a layer of at least substantially solid material.

[0084] Embodiment 10: the multiparticulate layer according to any of Embodiments 1 to 9, wherein one of the first and second layers comprises a paste. [0085] Embodiment 11: The intermediate structure formed during the manufacture of the earth tool includes: the earth tool body; a first layer of material disposed on at least a portion of the surface of the body, the first layer comprising: a first polymeric material; and many hard particles dispersed in the first polymeric material; and a second material layer disposed on at least a portion of the first material layer on its side opposite the body, the second material layer comprising: a second polymeric material; and many matrix metal particles dispersed in the second polymeric material. [0086] Embodiment 12: the intermediate structure according to Embodiment 11, wherein each first layer of material and second layer of material comprises a layer of solid material.

[0087] Embodiment 13: the intermediate structure according to Embodiment 11, wherein the first material layer comprises a paste layer, and the second material layer comprises a solid material layer.

[0088] Embodiment 14: an intermediate structure according to any of Embodiments 11 to 13, wherein at least a portion of the body surface includes a surface of the earth body of the rotary drill in a mud channel extending at least partially through the body of the earth rotary drill.

[0089] Embodiment 15: a method of applying hardfacing to the surface of an earth tool, comprising: mixing a plurality of hard particles, a plurality of matrix metal particles, a polymer material, and a liquid solvent to form a paste; spreading the paste on the surface of the substrate to form a layer of paste; removing liquid solvent from the paste layer to form at least a substantially solid layer comprising a plurality of hard particles, a plurality of matrix metal particles, and a polymeric material; removing at least a substantially solid layer from the surface of the substrate; applying at least a substantially solid layer to the surface of the earth body of the tool; heating the earth body of the tool to a first temperature while at least a substantially solid layer is on its surface and removing polymeric material from the earth body of the tool; and heating the earth body of the tool to a second temperature higher than the first temperature and sintering the at least many metal matrix particles to form a layer of hardfacing material on the surface of the earth body of the tool comprising a plurality of hard particles dispersed in the metal phase of the matrix formed from the many metal particles of the matrix. [0090] Embodiment 16: the method of Embodiment 15 wherein the application of at least a substantially solid layer to the surface of the earth body of the tool includes applying at least a substantially solid layer to the surface of the earth body of a rotary drill in a mud channel extending at least partially through the earth body rotary drill.

[0091] Embodiment 17: the method of Embodiment 15 or Embodiment 16, further comprising selecting the polymeric material to include a thermoplastic and elastomeric material.

[0092] Embodiment 18: the method of Embodiment 17, further comprising selecting the polymeric material to include at least one of styrene-butadiene-styrene, styrene-ethylene-butylene-styrene, styrendivinylbenzene, styrene-isoprene-styrene, and styrene- etylenstyren.

[0093] Embodiment 19: the method of Embodiment 17 or Embodiment 18, further comprising selecting the polymer material to include at least one of oil, polybutene, cyclobutane, polyethylene, polyethylene glycol, and polypropylene. [0094] Embodiment 20: a method of applying hardfacing to the surface of an earth tool, comprising: providing a first layer of material comprising a plurality of hard particles and a first polymeric material on the surface of the earth body of the tool; providing a second layer of material comprising a plurality of matrix metal particles and a second polymeric material adhered to the first layer of material on its side opposite the earth body of the tool; heating the earth body of the tool to a first temperature while a first layer of material and a second layer of material are on the body of the earth tool and removing the first polymeric material and the second polymeric material from the earth body of the tool; and heating the earth body of the tool to a second temperature higher than the first temperature and sintering the at least many metal matrix particles so as to form a layer of hardfacing material on the surface of the earth body of the tool comprising a plurality of hard particles dispersed in the metal phase of the matrix formed from the many metal particles of the matrix. [0095] Embodiment 21: the method of Embodiment 20, further comprising forming the second layer of material to include at least a substantially solid layer comprising a second polymeric material and matrix metal particles dispersed in the second polymeric material.

[0096] Embodiment 22: the method of Embodiment 20 or Embodiment 21, further comprising forming the first layer of material to include a paste comprising a plurality of hard particles, a first polymeric material, and a liquid solvent.

[0097] Embodiment 23: the method of Embodiment 21, further comprising: coating the surface of the at least substantially solid layer with a paste; and applying at least a substantially solid layer on the surface of the earth body of a paste tool sandwiched between the surface and at least a substantially solid layer.

[0098] Embodiment 24: The method of any of Embodiments 20 to 23, further comprising selecting the surface of the earth body of the tool to include the surface of the earth body of the rotary drill in a mud channel extending at least partially through the body of the earth rotary drill.

[0099] Embodiment 25: the method of any of Embodiments 20 to 24, further comprising selecting at least one of the first polymeric material and the second polymeric material to include a thermoplastic and elastomeric material.

[0100] Embodiment 26: the method of any of Embodiments 20 to 25, further comprising selecting the first polymeric material and the second polymeric material to have at least a substantially similar composition.

[0101] While the invention has been described herein with reference to the specific embodiments shown, it is clear to those skilled in the art that it is not quite as so.

<td>limited.</td><td>On the contrary, many are possible</td>

<td>additions</td><td>deletions and modifications in the presented</td>

<td>examples</td><td>performance without departing from the one claimed here</td>

scope of the invention, including its legal equivalents. In addition, the features of one embodiment may be combined with the features of another embodiment while they will still be within the scope of the invention as defined by the inventors. In addition, the invention can be used with various and various drill profiles as well as types of cutting elements and configurations.

21774 / EP / 12

EP 2 226 129 B1 multi-molecular mud channel (30) with the first layer (32)