MX2011007250A

MX2011007250A - Roller cones having non integral cutting structures, drill bits including such cones, and methods of forming same.

Info

Publication number: MX2011007250A
Application number: MX2011007250A
Authority: MX
Inventors: James L Overstreet; Robert J Buske
Original assignee: Baker Hughes Inc
Priority date: 2009-01-15
Filing date: 2010-01-14
Publication date: 2011-07-28
Also published as: BRPI1007049A2; CA2749482A1; WO2010083265A3; US20100175926A1; WO2010083265A2; EP2376738A2; RU2011133743A

Abstract

Methods of manufacturing roller cones for drill bits include providing both integral teeth and non-integral teeth on the roller cones. A layer of hardfacing may be applied to the integral teeth. Non-integral teeth may be formed on a body of a cone, or they may be separately formed from the body and attached thereto. In some embodiments, the non-integral teeth are formed by building-up the non-integral teeth from hardfacing material. Roller cones and earth-boring tools are formed using such methods.

Description

ROLLER CONES THAT HAVE CUTTING STRUCTURES NO INTEGRALS, DRILL BARRELS THAT INCLUDE SUCH CONES, AND METHODS FOR FORMING THEM DESCRIPTION OF THE INVENTION The present invention relates generally to rotary drill bits for drilling holes in underground deposits, to components of such drill bits, and to methods for manufacturing such drill bits and components.

Roller cone earth drilling drills are commonly used to drill underground ground deposits. One type of ground cone drilling of roller cones is a grounding drill bit of serrated teeth or steel teeth that typically comprises two or more cones with teeth projecting from the surface of each to couple the rock. The teeth are formed of hardened steel and generally have a regular cross-sectional shape (as seen in a plane perpendicular to the axis of rotation of the cone). Another type of roller cone drilling bit has ring structures that show substantially circular exteriors, which are referred to as "disk" or "disk cutters", and project from the surface of the cone to couple the rock. The discs are also formed of hardened steel and extend around a circumference of the cone. The surfaces between the toothed teeth or discs that couple the rock are usually coated with a layer of hard coating material to increase the wear resistance. Typical hard coating material can be formed from a particulate matrix composite material. Such particulate matrix composites include particles of hard material such as, for example, tungsten carbide dispersed through a metal matrix material (also referred to as a "binder" material). Particle matrix composites show relatively more corrosion resistance and wear resistance with respect to the hardened steel of the teeth and discs.

The provision of hard coating material on the surfaces of the teeth or discs can be achieved using manual welding processes or an automated hard coating system. Typical manual welding processes include a person holding a welding torch and a rod of hard coating material and welding a coating of hard coating material on the surface of a tooth. After a tooth has been coated, the person moves the torch, the hard coating material, and / or the cone to allow the next tooth to be coated. Automated processes can be very complex due to geometry, inaccessibility to the faces of each tooth or disc by a hard coating torch, and the number of teeth in a tooth cone.

If manual or automatic means are used to apply the hard coating to the roller cone, the proximity of the teeth and / or discs may make it difficult or impossible to weld. suitably the hard coating material to the surfaces of each tooth or disc. As such, there is a need in the art for improved methods for applying hard coating material to a cone for a roller cone auger.

In some embodiments, the present invention includes methods for forming a roller cone for a land drilling bit. A non-integral tooth may be formed adjacent to at least one integral tooth. For example, a non-integral tooth can be formed in an air gap between two integral teeth. As non-limiting examples, such an air gap can be located between at least two integral teeth in different rows of teeth, or such air gap can be located between at least two integral teeth in the same row of teeth.

In further embodiments, the present invention includes methods for forming a roller cone for a rotating ground drill bit in which at least one non-integral disk mill is provided in a SUMMARY Methods for making roller cones for drill bits include providing integral teeth and non-integral teeth in the roller cones. A layer of hard coating material can be applied to the integral teeth. Non-integral teeth can be formed in a cone body, or they can be formed separately from the body and connected to it. In some modalities, non-integral teeth are formed to construct non-integral teeth from the material of. hard coating. - Roller cones and terrestrial drilling tools are formed using such methods. roller cone adjacent to an integral disc cutter in the cone. For example, an air gap may be formed between two integral disc cutters, and at least one non-integral disk cutter may be provided in the air gap.

In further embodiments, the present invention includes methods for forming rotary ground boring bits in which a plurality of integral teeth is formed in a milling cutter, and hard coating material is deposited in the milling cutter to form at least one non-integral tooth in the milling cutter. the same. For example, the hard coating material can be deposited in the cutter in an air gap between two adjacent integral teeth, and the hard coating material can accumulate to form at least one non-integral tooth between the integral tooth. In addition, a hard coating layer can be applied to at least one surface in each of the adjacent integral teeth.

In further embodiments, the present invention includes methods for forming ground drill bits in which integral teeth are formed in a milling cutter, the hard coating material is applied to integral teeth, and a non-integral tooth is formed separately from the tooth. strawberry and is linked to the strawberry in an air gap between the integral teeth.

BRIEF DESCRIPTION OF THE DRAWINGS Although the specification concludes with the claims that particularly point out and distinctly claim what is interpreted as the present invention, the advantages of this invention can easily be ascertained from the description of embodiments of the invention when read together with the accompanying drawings. , in which : FIGURE 1 is a perspective view of a rotary terrestrial drill bit embodiment of the present invention; FIGURE 2 is an enlarged perspective view of a roller cone embodiment of the present invention; FIGURE 3 is an enlarged perspective view of a partially formed roller cone embodiment of the present invention; FIGURE 4 is an enlarged perspective view of another embodiment of a partially formed roller cone of the present invention; FIGURE 5 is an elongated partial view of another embodiment of a partially formed roller cone of the present invention; FIGURE 6 illustrates the hard coating material that is applied to the portion of the partially formed roller cone shown in FIGURE 5; FIGURE 7 illustrates a cutting structure formed by the application of hard coating material to the portion of the partially formed roller cone, as shown in FIGURE 6; FIGURE 8 illustrates an example of a robot that can be used to form the roller cones according to embodiments of the present invention; FIGURE 9 is an elongated partial view of a non-integral tooth that is applied to a portion of a partially formed roller cone; FIGURE 10 is a partial cross-sectional view of one embodiment of a roller cone of the present invention including a non-integral tooth disposed between two integral teeth of roller cones; FIGURE 11 is an elongated partial view of another embodiment of a non-integral tooth applied to a portion of a partially formed roller cone; FIGURE 12 is an elongated perspective view of another embodiment of a roller cone of the present invention; FIGURE 13 is an enlarged perspective view of another embodiment of a partially formed roller cone of the present invention; Y FIGURE 14 is an enlarged perspective view of another embodiment of a partially formed roller cone of the present invention.

Some of the illustrations presented herein are not interpreted as real views of any particular material, device, or system, but are idealized only as representations which are used to describe the present invention. Additionally, common elements between the Figures may retain the same numerical designation.

One embodiment of a ground drill 102 of the present invention is illustrated in FIGURE 1 as a non-limiting example of a drill bit employing a plurality of roller cones. The drill bit 102 includes a bit body 104 having three bit bases 106. A cone 109 that is mounted rotatably on a support pin (not shown)) in each of the auger bases 106. The cone body 108 (FIGURE 2) of each cone 109 may be at least substantially comprised of, for example, an iron-based alloy (e.g., steel). In the embodiment shown in FIGURE 1, each cone 109 has three rows of teeth 110, 111 that include an outer row 112, an inner row 114, and an intermediate row 116. The cones 109 of the drill bit 102 include both integral teeth and non-integral teeth, as discussed in further detail below.

A circumferential recess 118 may be disposed between the inner row 114 and the intermediate row 116, as well as between the intermediate row 116 and the outer row 102. Each tooth 110 is separated from the adjacent teeth in the same row by a valley 128. Each cone 109 also has a bore surface 130 which defines the diameter of the auger and the borehole.

Modes of drill bits 102 and cones 109 of the present invention may have any number of rows of teeth 110, 111 and may have any number of teeth 110, 111. In addition, embodiments of drill bits 102 and cones 109 of this invention may have teeth 110, 111 that are arranged in any pattern in the cones 109, and the teeth 110, 111 may not be arranged in rows.

The drill bit 102 has a threaded section 122 at its upper end for connection to a drill string (not shown). The drill bit 102 also has an internal fluid impeller extending through the auger body 104, as well as fluid passages extending from the fluid impeller to the nozzles 124. During drilling, the drilling fluid may pumped to the center of the drill string, through the fluid impeller in the fluid passages, and out of the nozzles 124.

Each auger base 106 may also include a lubricant reservoir for supplying lubricant to the support surfaces between the cones 109 and the support bolts on which it is mounted. A pressure compensator 126 can be used to equalize the lubricant pressure with the fluid pressure of the borehole, as is known in the art.

FIGURE 2 is an elongated view of a cone 109 of the drill bit 102 shown in FIGURE 1. As mentioned previously, the cone 109 includes integral teeth 110 and non-integral teeth 111. As used herein, the term "integral tooth" means a tooth having at least a major portion thereof that is formed integrally with an integral part of the cone body 108 of a cone 109 of rollers so that no limit Identifiable discrete exists between the cone body 108 of the roller cone 109 and the main portion of the tooth. Such integral teeth 110 can be formed by machining a cone body 108 of a roller cone 109 using machining methods such as, for example, lathe, rectification and / or drilling. As used herein, the term "non-integral tooth" means a tooth having a major portion thereof that is formed separately from and connected to the cone body 108 of the roller cone 109 so that no limit Identifiable discrete exists between the cone body 108 of the roller cone 109 and the main portion of the tooth. In the exemplary embodiment shown in FIGURE 2, each of the outer row 112 and the inner row 114 comprises the integral teeth 110, while the intermediate row 116 comprises non-integral teeth 111.

At least one outer surface of each tooth 110, 111 of the cone 109 may comprise a hard coating material 120 (FIGURES 1 and 2). For example, in some embodiments, a layer of hard coating material 120 may be applied to each integral tooth 110 of cone 109, and a major portion of each non-integral tooth 111 of cone 109 may be formed from hard coating material 120. In such embodiments, various welding processes including, for example, inert gas-metal welding (MIG) processes, inert gas-tungsten welding (TIG) process, plasma arc welding (PAW) process can be used for applying a layer of hardcoat material 120 on the integral teeth 110 and for forming a major portion of the non-integral teeth 111 when constructing the teeth 111 from the hardcoat material 120 in a layer-by-layer process. In addition, the hardcoat material 120 can be applied manually or robotically.

As shown in FIGURE 2, the teeth 110, 111 of the cone 109 are formed very close to each other. If each of the teeth 110, 111 were formed integrally with the cone 109 (ie, if they were integral teeth 110), it may be difficult to apply a layer of hard coating material 120 on each of the teeth 110, 111 due to the difficulty of placing a welding torch between the teeth 110, 111. In other words, it can be difficult to properly place a welding torch between the teeth 110, 111 to apply hard coating material 120 to the surfaces thereof. the physical interference between the welding torch and the adjacent teeth 110, 111. As a result, the areas of the teeth 110, 111 that could be covered with hard coating material 120 can be limited. In addition, it may be difficult to modify the shape, size, and / or configuration of the teeth 110, 111 of the cone 109 to facilitate such application of hard coating material 120 without comprising a desirable drilling performance of the drill bit. Additional embodiments of the present invention include methods for forming roller cones for rotating ground drill bits that can be used to overcome such problems, as described in further detail herein below.

An exemplary embodiment of the method of the present invention that can be used to form the roller cone 109 shown in FIGURE 2 is described below with reference to FIGURE 3. A cone body 108 can be machined to form the intermediate cone structure 166 shown in FIGURE 3. The intermediate cone structure 166 includes an outer row 112 of integral teeth 110 and an inner row 114 of integral teeth 110. An air gap 132 may be formed between the integral teeth 110 of the outer row 112 and the integral teeth 110 of the inner row 114 at the location in the cone body 108 in which the non-integral teeth 111 (FIGURE 2) will be formed accordingly . The outer row 112 and the inner row 114 of the integral teeth 110 may extend circumferentially about an axis of rotation of the cone body 108, as shown in FIGURE 3.

A layer of hard coating material 120 (FIGURE 5) can be applied to one or more surfaces of each integral tooth 110 of outer row 112 and inner row 114. At least a portion of the hardcoat material 120 is applied to the surfaces of the integral teeth 110, the welding torch used to apply the hardcoat material 120 may be placed at least partially within the air gap 132 between the outer row 112 and row 114 inside. By providing the air gap 132 between the integral teeth 110 of the outer row 112 and the integral teeth 110 in the inner row 114, the problems of physical interference can be reduced or eliminated to facilitate the application of the hard coating material 120 to the integral teeth 110. .

After applying a layer of hardcoating material 120 to one or more surfaces of the integral teeth 110, the non-integral teeth 111 can be formed in, or formed separately and connected to, the cone body 108 in the air gap 132 between the outer row 102 and inner row 114 to form cone 109 shown in FIGURE 2.

Another embodiment of the method of the present invention that can be used to form a roller cone similar to roller cone 109 shown in FIGURE 2 is described below with reference to FIGURE 4. A cone body 108 can be machined to form structure 170 intermediate cone shown in FIGURE 4. The intermediate cone structure 170 includes an outer row 172 of integral teeth 110, an inner row 174 of integral teeth 110, and an intermediate row 176 of integral teeth 110. An air gap 182 can be formed between the integral teeth 110 of the outer row 172, between the integral teeth 110 of the inner row 174, and between the integral teeth 110 of the intermediate row 176. The air gaps 182 can be located in the cone body 108 at locations in which the non-integral teeth 111 (FIGURE 2) will be formed subsequently. Each air gap 182 can be sized to accommodate one or more non-integral teeth 111.

A layer of hard coating material 120 (FIGURE 2) can be applied to one or more surfaces of each integral tooth 110 in outer row 172, inner row 174, and intermediate row 176. At least a portion of the hardcoat material 120 is applied to the surfaces of the integral teeth 110, the welding torch used to apply the hardcoat material 120 can be placed at least partially within the air gaps 182 between the teeth 110. integrals in each of row 172 outside, row 174 inside, and row 176 intermediate. By providing the air gaps 182 between the integral teeth 110 in the outer row 172, the inner row 174, and the intermediate row 176, the problems of physical interference can be reduced or eliminated to facilitate the application of the hard coating material 120 to the teeth 110. integrals After applying a layer of hardcoating material 120 to one or more surfaces of the integral teeth 110, the non-integral teeth 111 can be formed in, or formed separately and connected to, the cone body 108 and air gaps 182 between integral teeth 110 in each of outer row 172, inner row 174, and intermediate row 176 to form a cone-like cone 109 shown in FIGURE 2.

In additional embodiments of the present invention, intermediate cone structures may be formed to comprise any number of missing teeth and / or rows to subsequently provide non-integral teeth therein. For example, an intermediate cone structure can include an air gap 132 between rows of teeth, as previously described with respect to FIGURE 3, as well as the air gap 182 between the integral teeth 110 in the same row of teeth, as previously described with respect to FIGURE 4.

In some embodiments of the present invention, a marking feature or structure may be provided in a cone body 108 of an intermediate cone structure at each location in which a non-integral tooth 111 will be formed in the cone body 108 or be connected to the 108 body of cone. FIGURE 5 is an elongated partial view of an intermediate cone structure embodiment of the present invention, similar to that shown in FIGURE 4, and illustrates a second marking feature comprising a dial adapter 134 formed in the body 108 of cone in an air gap 182 adjacent to an integral tooth 110. The dial adapter 134 defines an area on the body surface 108 of at least one air gap 132 in which the non-integral tooth 111 will be formed or connected. As shown in FIGURE 5, the dial adapter 134 may comprise a relatively small projection formed in the cone body 108 having a size that corresponds at least substantially with a base size of a non-integral tooth 111 that will be formed or connected to the adapter 134 of dialing The marking adapter 134 may extend, for example, approximately 1/4 inch (approximately 0.2825 cm) from an outer surface surrounding the cone body 108.

In further embodiments, a cone body 108 may be engraved or inscribed to mark the location of the non-integral teeth 111 that will be formed or recorded to the cone body 108. For example, if a row of non-integral teeth 111 is provided in a cone body, as shown in FIGURE 3, the lines may be engraved or inscribed in the cone body 108 extending circumferentially around the cone body 108 on an axis of rotation of the cone body 108 to define longitudinal boundaries of the non-integral teeth 111 to be formed or engraved to the cone body 108, and the lines may be engraved or inscribed in the cone body 108 extending longitudinally between the lines of circumference to define the circumferential boundaries of the non-integral teeth 111 to be formed or engraved to the cone body 108. Such marks may be formed during the machining process or processes used to form the integral teeth 110 in the cone body 108.

As previously mentioned, in some embodiments of the present invention, one or more non-integral teeth 111 may be formed in a cone body 108 by depositing the hard coating material 120 on the cone body 108 such that teeth are constructed 111 non-integral on the cone body 108 from hard coating material 120. FIGURES 6 and 7 illustrate an example of the embodiment of the method of the present invention that can be used to form non-integral teeth 111 in a cone body 108. With reference to FIGURE 6, the hardcoating material 120 can be deposited in the cone body 108 (for example, in a marking adapter 134 of a cone body 108 in an air gap 132 or between iron 182) in a layer process per layer (i.e., successively deposited layers of the hardcoat material 120 that is deposited on the previously deposited layers of the hardcoat material 120) to form one or more non-integral teeth 111 similar to those shown in FIGURE 7 that they comprise multiple layers of hard coating material 120. For example, an integral tooth 110 may be formed in a cone body 108 and a hard coating material 120 may be applied to an integral tooth surface 110. A marking adapter 134 can be formed in the cone body 108 adjacent the integral tooth 110, and the hard coating material 120 can be deposited in the marking adapter 134 to build a non-integral tooth 111 in the marking adapter 134 from the material 120 hard coating. By way of example and without limitation, the hard coating material 120 can be applied for example, by manually welding the hard coating material 120 to the cone body 108 using a welding torch 138 and a tube or rod 136 comprising the material 120 of hard coating. The hard coating tube 136 and the welding torch 138 can be moved through the surfaces of the integral tooth 110 and the reaming adapter 134 to weld the hard coating material 120 to the integral tooth 110 and the marking adapter 134. The layers of the hardcoat material 120 can be sequentially deposited on the marking adapter 134 in a layer-by-layer process to form a non-integral tooth 111 having a desirable height and conformation.

After forming the non-integral tooth 111 as shown in FIGURE 7, the surfaces of the non-integral tooth 111 can be machined or ground when necessary or desirable to remove a portion of the hard coating material 120 to provide the non-integral tooth 111 with the desirable geometry and dimension. In some embodiments, a template structure can be placed on the non-integral tooth 111 and the non-integral tooth 111 can be machined to cause the non-integral tooth 111 to conform to the surfaces of the template. Using a template can help ensure that the non-integral tooth 111 conforms to a desirable shape and dimension.

The hardcoat material 120 can have any suitable composite composition comprising a discontinuous hard phase dispersed within a continuous matrix phase. For example, the hard coating material may comprise relatively hard ceramic particles dispersed through a metal matrix material. Many hard coating compositions are known in the art and can be employed as hard coating material 120 in embodiments of the present invention. Examples of such hard coating material compositions are described in, for example, U.S. Patent No. 5,663,512, entitled Hard Coating Composition for Ground Drilling Auger, issued September 2, 1997, U.S. Patent No. 6,248,149, entitled "Composition". of Hard Coating for Ground Drilling Augers using Microcrystalline Tungsten Carbide and Spherical Melt Tungsten Carbide, issued June 19, 2007, and US Pending Patent Application Serial No. 11/823, 800, entitled Compound Perforation Augers of Hard Coated Particle Matrix and Methods to Fabricate and Repair Such Drill Bits Using Hard Coating Materials, filed on October 31, 2007.

The hard coating material 120 can be applied to the cone body 108 using welding techniques. By way of example and without limitation, the hardcoat material 120 can be applied manually using a welding torch and a rod or tube comprising the hardcoating material 120. A tube comprising hard coating material may comprise a hollow cylindrical tube formed from metal material that will eventually form a continuous metallic matrix phase of hard coating material 120. The tube can be filled with hard particles, such as, for example, tungsten carbide particles which will eventually form a discontinuous hard phase of hard coating material 120. At least one end of the hollow cylindrical tube may be sealed. The sealed end of the tube can then be fused or welded onto the surface of the cone body 108. When the tube is melted, the hard particles inside the hollow cylindrical tube are mixed and suspended in the molten matrix material as it is deposited on the cone body 108. In additional methods, a solid rod of hard coating material 120 can be used in place of a tube. The welding torch may comprise, for example, an arc welding torch or a fuel torch (for example, an oxyacetylene torch). In additional methods, a plasma torch can be used to weld the hard coating material 120 to the cone body 108. In such methods, the hard powder coating material 120 (e.g., hard particles and particles comprising the metal matrix material) can be fed through the plasma torch and onto the cone body 108.

In additional embodiments, the hardcoat material 120 can be deposited using an automated (e.g., robotic) process. For example, a welding torch and a cone body 108 can be manipulated in a robotic manner while using the welding torch to deposit the hard coating material 120 on the cone body 108. Automated welding processes and systems that can be used to deposit the hardcoat material 120 in the cone body 108 are described for example in U.S. Patent No. 5,233,150 entitled Methods for Production of Workpieces by Welding Equipment, presented on 3 August 1993, US Patent Application Serial No. 10 / 095,523 entitled Method and Apparatus for Forming a Workpiece, filed on March 13, 2002, and US Patent Application Serial No. 12 / 257,219, entitled Method and Apparatus for Automated Application of Hard Drilling to Drilling Auxiliary Material, filed on October 23, 2008.

FIGURE 8 illustrates an example of an automated robotic system that can be used to apply the hardcoat material 120 to the cone body 108 (e.g., to apply a layer of hardcoat material 120 to surfaces that integral teeth 110 and / or constructed on the non-integral teeth 111 from the hard coating material 140. As shown in FIGURE 8, a robotic device 141A can be used to manipulate a roller cone body 108, and the second robotic device 141B can be used to manipulate a welding torch 138 when the welding torch 138 is used to deposit hard coating material 120 on the cone body 108. In one embodiment, the cone body 108 can remain stationary while the second robotic device 141B manipulates the torch 138. of welding around the surface of the cone body 108. In another embodiment, the welding torch 138 may remain The first robotic device 141A manipulates the cone body 108 so that the surface of the cone body 108 makes contact with the welding torch 138. In a further embodiment, the welding torch 38 and the cone body 108 can be manipulated by the first and second robotic devices 141A and 141B to contact the welding torch 138 with the surface of the cone body 108. A laser sensor 146 can be used to determine the distance between the welding torch 138 and the surface of the cone body 108 and / or to measure a thickness of the hard coating material 120 applied to the surface of the cone body 108. Each of the first and second robotic devices 141A and 141B may be provided with multiple (e.g., five, six or more) axes of rotation 144 (or degrees of freedom) to provide sufficient freedom of movement between the welding torch 138 and the body 108 of cone. In some embodiments, the welding torch 138 may comprise an arc welding torch transferred by pulse plasma (PTAW) in which the torch is used to generate a plasma column between the welding torch 138 and the cone body 108 , or an arc transferred by plasma in which the current of the plasma transfer arc can be pressed when the welding torch 138 is used to deposit the hard coating material 120 on the cone body 108.

In some embodiments, a hard coating material 120 used to form non-integral teeth 111 may be established at least substantially identical in composition to a hard coating material 120 that is applied over the surfaces of the integral teeth 110. In additional embodiments, the hardcoat material 120 having a first composition can be used to form the non-integral teeth 111 in a cone body 108, and the hardcoat material 120 having a different second composition can be used to form a layer of hard coating material 120 on the integral teeth 110 in the cone body 108.

In some embodiments, the hardcoat materials 120 having different compositions can be used to form different portions or regions of the non-integral teeth 111. For example, an interior region of non-integral teeth 111 can be formed from and comprise hard coating material 120 having the first composition, an outer region of non-integral teeth 111 can be formed from and comprise a coating material 120 hard that has a second composition different from that of the first hard coating material 120. In some embodiments, for example, the composition of the first hardcoating material 120 may exhibit a toughness that is relatively greater than a toughness exhibited by the composition of the second hardcoating material 120, and the composition of the second hardcoated material 120 may showing a hardness and / or wear resistance that is relatively greater than its hardness and / or wear resistance exhibited by the composition of the first hard coating material 120.

As previously mentioned, the non-integral teeth 111 can be formed separately from the cone body 108 and connected subsequently to it. FIGURE 9 is an elongated partial view of the cone body 108 and illustrates non-integral teeth 111 that are deposited and connected to the cone body 108 in an air gap 132 adjacent an integral tooth 110. The non-integral tooth 111 can be formed separately from the cone body 108. For example, the non-integral tooth 111 may comprise a particulate matrix composite material (e.g., a hard coating material) that includes hard particles (e.g., tungsten carbide particles) dispersed within the metal matrix material (eg. example, nickel metal, cobalt, or iron alloy).

The non-integral tooth 111 can be formed using, for example, a sintering process in which an unprocessed body of particles is sintered to form the non-integral tooth 111. Such an unprocessed body of particles can be formed using the known raw body forming techniques including, for example, powder processing techniques, powder injection molding techniques, and mold casting techniques (e.g. grout casting and ribbon casting techniques). For example, in an injection molding process, a powder mixture comprising hard particles and particles of a metal matrix material (and, optionally, organic binders, lubricants, compaction acids, etc.) can be injected into the cavity of mold having a shape corresponding to a desirable shape for a non-integral tooth 111 to form an unprocessed body. The unprocessed body can then be removed from the mold and synthesized to a desired final density in an oven to form non-integral tooth 111.

By way of example and without limitation, the non-integral tooth 111 may be connected to the cone body 108 by link (eg, bronze-weld or weld) of the non-integral tooth 111 to the cone body 108 with a metallic material. The metallic material 154 may comprise, for example, an iron alloy, a nickel alloy, or a cobalt alloy. FIGURE 10 is a partial cross-sectional view of a non-integral tooth 111 connected to a cone body 108 between the integral teeth 110. As shown in FIGURE 10, a metallic material 154 can be deposited between at least a portion of the non-integral tooth 111 and the cone body 108. Figure 11 is a partial perspective view of a non-integral tooth 111 welded to a cone body 108 with a bead of metallic material 154 adjacent an integral tooth 110. The metallic material cord 154 can be welded to the non-integral tooth 111 and the cone body 108 around the perimeter of the base of the non-integral tooth 111.

Producing a non-integral tooth 111 separately and subsequently connecting the non-integral tooth 111 to the cone body 108 may be relatively useful for smaller cone bodies 108 in which it may be difficult to form a non-integral tooth 111 directly on the body 108 of cone, as previously described herein.

In further embodiments, the non-integral tooth 111 and the cone body 108 can be co-synthesized together in an oven to link the non-integral tooth 111 to the cone body 108.

Although previously described embodiments of the present invention include a roller cone 109 having integral teeth 110 and non-integral teeth 111, further embodiments of the present invention include roller cones having all non-integral teeth 111 and integral teeth 110. Such non-integral teeth 111 can be formed directly in the body 108 of how or form separately and connect to the cone body 108 as previously described herein.

Additional embodiments of the present invention may comprise cutting structures other than teeth. For example, FIGURE 2 illustrates an exemplary embodiment of a roller cone 177 of the present invention having three disc cutters. The roller cone 177 has an outer disk cutter 183, an inner disk cutter 184, and an intermediate disk cutter 186. Each of the disk cutters 183, 184, 186 extends circumferentially around the cone body 108 on an axis of rotation thereof. In additional embodiments, the roller cone 177 may comprise more or less 3 disc cutters. One or more of the disk cutters 183, 184, 186 can be an integral disk cutter that is integrally formed with and integral with the cone body 108. Additionally, one or more of the cutters 183, 184, 186 may comprise a non-integral disk cutter which is formed in the cone body 108 or is formed separately from the cone body 108 which is connected thereto.

An example of an embodiment of a method of the present invention that can be used to form a cone, such as the roller cone 177 shown in FIGURE 12, is described below with reference to FIGURE 13. As shown in FIGURE 13 , a cone body 108 can be formed (e.g., machined) to form an intermediate cone structure 178 comprising an integral disc cutter 183, integral disk cutter 184, and an air gap or recess 132 between the integral disk cutter 183 and the integral disk strawberry 184.

A layer of hardcoating material 120 can be applied to an integral disc cutter 183 and the integral disc cutter 184 using techniques known in the art as previously described. After the hardcoating material 120 is applied to the integral disk cutter 183 and the integral disk cutter 184, the non-integral disk cutter 186 can be formed directly on the cone body 108, a non-integral disk cutter 186 can be formed separately from the cone body 108 and subsequently connected thereto to form the roller cone 177 shown in FIGURE 12.

The non-integral disc cutter 186 can be provided in the cone body 108 in at least one air gap 132, for example, by depositing the hard coating material 120 on the surface of the cone body 108 in at least one air gap 132 and forming at least one non-integral disc cutter 186 from hard coating material 120.

FIGURE 14 is an enlarged perspective view of another embodiment of a roller cone 195 of the present invention. The roller cone 195 is similar to the roller cone 177 shown in FIGURE 12 and includes the cone body 108, an integral outer disc cutter 192, an anterior integral disc cutter 194, and an intermediate non-integral disc cutter 196. . In the embodiment of FIGURE 14, however, the disk cutters 192, 194, 196 have a serrated cutting edge. The roller cone 195 shown in FIGURE 14 can be formed using the modalities of the methods of the present invention, as previously described herein.

Although the present invention is described herein with respect to embodiments of the rotary ground drilling tools including roller mills and methods of forming such drill bits, the present invention also encompasses other types of ground drilling tools such as , for example, reamers, milling cutters, and so-called "hybrid drills" that include one or more roller cones and fixed cutters on pallets or other support structures, as well as components for forming such tools. Thus, as used herein, the term "drill bit" includes and encompasses all prior terrestrial drilling tools, as well as components and subcomponents of such structures.

Although the present invention has been described herein with respect to certain embodiments, those of ordinary skill in the art will recognize and appreciate that they are not limited in this manner. In fact, many additions, deletions, and modifications to the embodiments described herein can be made without departing from the scope of the invention as claimed after this. In addition, features of one embodiment may be combined with features of another embodiment while still encompassing the scope of the invention as contemplated by the present invention.

Claims

CLAIMS 1. A method for forming a roller cone for a terrestrial rotary drilling bit, characterized by: forming at least two integral teeth in a cone body with at least one air gap therebetween; Y providing at least one non-integral tooth in the cone body in at least one air gap. 2. The method in accordance with the claim 1, further characterized in that it comprises applying a hard coating material to at least one surface of each tooth of at least two integral teeth. 3. The method according to claim 1, characterized in that forming at least two integral teeth in the cone body comprises: forming a first row of integral teeth extending circumferentially on an axis of rotation of the cone body; Y forming a second row of integral teeth extending circumferentially on an axis of rotation of the cone body; Y wherein at least one air gap comprises at least one air gap between a tooth of the first row of integral teeth and a tooth in the second row of integral teeth. 4. The method according to claim 1, characterized in that forming at least two integral teeth in the cone body comprises forming at least one row of integral teeth extending circumferentially on an axis of rotation of the cone body, and wherein at least one air gap between at least two integral teeth comprises at least one air gap between two teeth of at least one row of integral teeth. 5. The method according to claim 1, characterized in that providing at least one non-integral tooth in the cone body in at least one air gap comprises providing two or more non-integral teeth in the cone body in at least one air gap. 6. The method according to claim 1, characterized in that it comprises: marking an area on a cone body surface in at least one air gap; Y providing at least one non-integral tooth in the area marked on the surface of the cone body in at least one air gap. 7. The method according to claim 6, characterized in that marking an area on the surface of the cone body comprises forming an adapter in the cone body at least in an air gap and wherein forming at least one non-integral tooth comprises forming by at least one non-integral tooth in the adapter. 8. The method in accordance with the claim 1, characterized in that forming at least one non-integral tooth in the cone body in at least one air gap comprises: successively depositing multiple layers of hard coating material on the cone body in at least one air gap; Y forming at least one non-integral tooth of multiple layers of hard coating material. 9. The method according to claim 8, further characterized in that it comprises robotically manipulating the cone body while using a welding torch to deposit multiple layers of hard coating material. 10. The method according to claim 9, further characterized in that it comprises: use the welding torch to generate an arc transferred by plasma; Y driving an arc current transferred by plasma as the welding torch is used to deposit the multiple layers of hard coating material. The method according to claim 7, characterized in that successively depositing the multiple layers of hard coating material comprises: forming an interior region of at least one non-integral tooth from a first hard coating composition; Y forming an outer region of at least one non-integral tooth from a second hard coating composition that differs from the first hard coating composition. 12. The method according to claim 7, further characterized in that it comprises removing at least a portion of the hard coating material from at least one non-integral tooth to provide at least one non-integral tooth with a desired shape. 13. The method according to claim 12, further characterized in that it comprises placing a template on at least one non-integral tooth and machining at least one non-integral tooth to conform to the template. 14. The method according to claim 1, characterized in that it comprises providing at least one non-integral tooth in the cone body in at least one air gap comprising: forming at least one non-integral tooth separately from the cone body; Y connect at least one non-integral tooth to the cone body. 15. The method according to claim 14, characterized in that forming at least one non-integral tooth comprises: injecting a powder mixture comprising hard particles and particles of a metal matrix material into a mold cavity to form an unprocessed body; Y sintering the unprocessed body into a desired final density to form at least one non-integral tooth. 16. The method according to claim 14, characterized in that connecting at least one non-integral tooth to the cone body comprises connecting at least one non-integral tooth to the cone body with a metallic material. 17. The method according to claim 14, characterized in that linking at least one non-integral tooth to the cone body with the metallic material comprises: providing the metallic material between at least one non-integral tooth and the cone body; Y co-sintering at least one non-integral tooth, the cone body, and the metallic material. 18. A method for forming a roller cone for a terrestrial rotary drilling bit, characterized in that it comprises: forming at least two integral disk cutters in a cone body extending circumferentially to the cone body on an axis of rotation of the cone body; leave at least one air gap between at least two integral disk cutters; Y providing at least one non-integral disc cutter in the cone body in at least one air gap. 19. The method according to claim 18, characterized in that it comprises providing a non-integral disc cutter in the cone body in at least one air gap comprising: depositing hard coating material on the surface of the cone body in at least one air gap; Y forming at least one integral disk bur of the hard coating material. 20. The method in accordance with the claim 18, characterized in that it comprises forming a serrated edge in at least one non-integral disc mill. 21. The method according to claim 20, characterized in that forming at least one non-integral tooth in the air gap comprises successively depositing a layer of hard coating material in the air gap using a welding torch. 22. A method for forming a roller cone for a terrestrial rotary drilling bit, characterized in that it comprises: forming at least one integral disk cutter in a cone body circumferentially extending the cone body on an axis of rotation of the cone body; Y providing at least one non-integral disc burr in the cone body. 23. A method for forming a terrestrial drilling bit, the method characterized in that it comprises: forming a plurality of integral teeth in at least one milling cutter; forming an air gap between at least two integral teeth adjacent to the plurality of integral teeth; applying a hard coating layer to at least one surface in each of at least two integral teeth adjacent to the plurality of integral teeth; Y deposit hard coating material in the air gap between at least two adjacent integral teeth and constructing at least one non-integral tooth in the gap using the hard coating material deposited. 24. A method for forming a terrestrial drilling bit, the method characterized in that it comprises: forming a plurality of integral teeth in at least one milling cutter; providing an air gap between at least two integral teeth adjacent to the plurality of integral teeth; applying a hard coating layer to at least one surface of each of at least two integral teeth adjacent to the plurality of integral teeth; forming at least one non-integral tooth separately from at least one milling cutter, comprising: molding an unprocessed body comprising a plurality of hard particles and a plurality of particles comprising a metal matrix material; Y sinterize the unprocessed body to form the non-integral tooth; Y connecting at least one non-integral tooth in at least one milling cutter in the air gap between at least two adjacent integral teeth with a metallic binder material. 25. A terrestrial drilling bit, characterized in that it comprises: a body having at least one auger base; Y a roller cone mounted at least on the auger base and which can rotate at least on the auger base about a rotation axis; at least one integral tooth formed on the roller cone surface; a hard coating material deposited on at least one surface of at least one integral tooth; at least one non-integral tooth connected to the surface of the roller cone adjacent to at least one non-integral tooth, at least one non-integral tooth comprising a composite material of particle matrix. 26. The land drilling bit according to claim 25, characterized in that at least one non-integral tooth comprises an inner region having a first hard coating composition in an outer region having a second hard coating composition, the first composition of Hard coating exhibits a higher tenacity than the toughness exhibited by the second hard coating composition, and the second hard coating composition exhibits greater wear resistance than a wear resistance exhibited by the first hard coating composition. 27. The land drilling bit according to claim 25, characterized in that at least one non-integral tooth comprises multiple layers of hard coating material.