Abstract: A drill member for percussive rock drilling is formed by forming a compound component and friction welding the compound component to the end of a drill rod. The compound component is formed by welding a core part within a shell part and machining a thread into either the shell part (male thread) or core part (female thread). The part in which the thread is machined is formed of low alloy steel, and the other part is formed of stainless steel, wherein the thread bottom is formed of stainless steel, and the thread crests are formed of low alloy steel.

Abstract: A method for forming a drill bit body is disclosed which comprises infiltrating powdered tungsten carbide with a binder alloy in a mold. The mold has therein at least one displacement adapted to form a mounting pad for a cutting element. The displacement comprises a substantially cylindrical body having a diameter selected to substantially conform to a radius of the cutting element and a projection adapted to form a relief groove under a position of a diamond table in the cutting element when the cutting element is mounted on the pad. The width of the relief groove is selected so that the relief groove extends back from an outer surface of the bit body at least about 40 percent of that portion of a thickness of the diamond table which does not extend past the outer surface.

Abstract: A superhard compact having an improved superabrasive-substrate interface region design for use in drilling bits, cutting tools and wire dies and the like. This compact is designed to provide an interface design to manipulate residual stresses to enhance the working the strength of the compact. The compact is provided with a network on interface features that share common walls to form cavities.

Abstract: Roller cone bits include a steel bit body having a leg extending therefrom. A steel cone is disposed on the leg and includes steel cutting elements projecting outwardly therefrom. One of the cutting elements comprises a steel base integral with the cone and that projects therefrom. A cutting element end is attached to the base portion and extends to form a cutting element tip. The base and end portions are attached when the cone base are in a preexisting rigid state. The end portion comprises a wear resistant material having a material microstructure comprising a first phase of grains selected from the group of carbides, borides, nitrides, and carbonitrides of W, Ti, Mo, Nb, V, Hf, Ta, and Cr refractory metals; and a second phase of a binder material selected from the group consisting of Co, Ni, Fe, and alloys thereof.

Abstract: Drill bit reinforcing members or blanks of this invention are formed from high-strength steels having a carbon content less than about 0.3 percent by weight, a yield strength of at least 55,000 psi, a tensile strength of at least 80,000 psi, a toughness of at least 40 CVN-L, Ft-lb, and a rate of expansion percentage change less than about 0.0025%/° F. during austenitic to ferritic phase transformation. In one embodiment, such steel comprises in the range of from about 0.1 to 0.3 percent by weight carbon, 0.5 to 1.5 percent by weight manganese, up to about 0.8 percent by weight chromium, 0.05 to 4 percent by weight nickel, and 0.02 to 0.8 percent by weight molybdenum. In another example, such steel comprises in the range of from about 0.1 to 0.3 percent by weight carbon, 0.9 to 1.5 percent by weight manganese, 0.1 to 0.5 percent by weight silicon, and one or more microalloying element selected from the group consisting of vanadium, niobium, titanium, zirconium, aluminum and mixtures thereof.

Abstract: A method of forming a tooth rock bit is disclosed. In one embodiment, the method includes attaching the at least one cutting element to a surface of a cone, and depositing a hard facing layer on at least one cutting element prior to the attaching.

Abstract: A roller cone body defines a circumferential channel or race into which a plurality of cutter or wear segments are mounted. The wear segments may be of any appropriate contour or shape, such as for example chisel, spherical, or even flat face and are preferably made or carbide. The wear elements may be all the same within a channel or race, or they may be varied within a race as needed for a particular application.

Abstract: A cutting element for a drill bit used in drilling subterranean formations is formed with an internal chamber or passage for the flow of drilling fluid therethrough. The cutting element includes a substrate having at least one internal passage, and prior to attaching a superabrasive table thereto, the at least one internal passage is filled with a removable, substantially incompressible filler material. Attachment or bonding of the superabrasive table to the substrate under high temperature and high pressure is accomplished without significant distortion of the shape and size of the internal passage. The filler material may be a crystalline salt such as sodium chloride or halite, which is removable by dissolution in water, or may be boron nitride or a volcanic material such as Pyrofolyte material which is mechanically removable.

Abstract: A method of forming milled teeth on a roller cone of a milled tooth roller cone rock bit includes shaping a crest of a chisel shaped milled tooth on the roller cone. The crest is shaped such that the crest has a convex profile from one corner to an opposite corner of the crest. Such a crest is adapted to produce at least one of a convex axial stress distribution, a substantially even axial stress distribution, and a substantially smooth axial stress distribution. Further, the forming includes radiusing each of the corners at the ends of the crest of the chisel shaped milled tooth.

Abstract: A structural matrix drill bit body having different binder materials in different spatial locations as well as a method for forming the same, is provided. The different binder materials provide different functional properties to the different spatial locations of the drill bit body. The method for forming such a structural matrix body includes providing a matrix material within a mold, then infiltrating the matrix material with at least two binder materials which provide different functional properties in combination with the material. The arrangement is then heated and the heating process causes the different binder materials to infiltrate different spatial locations of the drill bit body.

Abstract: The present invention relates to a connection rod (1) for rock drilling comprising a first rod part (2) which has an external thread (4) provided at one end thereof, wherein the end of the rod opposite to said one end includes an end portion (6) which carries an internal thread (5), wherein the end portion (6) is joined to the first rod part (2) by friction welding and wherein the end portion (6) has been heat treated prior to being joined to said first rod part (2).

Abstract: Disclosed is a rolling cone cutter and drill bit employing multiple inserts retained as a cluster in an aperture in the cone cutter. Apertures in which the insert clusters are retained are multilobed apertures formed by intersecting bores formed in the cone steel. The apertures may also be created by forming spaced apart bores and milling regions of the cone steel that extends between the bores. The inserts in a cluster may be retained within the aperture to differing depths, may extend above the cone steel to differing extension lengths, and may have cutting portions having a variety of shapes. The inserts in a cluster may be made of different materials in order to optimize cutting duty.

Abstract: The invention is directed to a roller cone drill for drilling earth formations and a method of using the same. The drill bit includes a bit body and a plurality of roller cones attached to the bit body and able to rotate with respect to the bit body. The drill bit further includes a plurality of cutting elements disposed on each of the roller cones, an offset of at least about 0.375 inches; and a journal angle less than about thirty degrees. In one embodiment, the drill bit includes three roller cones. In another embodiment, the cutting elements of the bit are arranged on each cone so that cutting elements on adjacent cones intermesh between the cones.

Abstract: A method is disclosed for applying hardfacing to a shirttail portion of a roller cone drill bit, including masking around the shirttail portion of the bit and operating a high pressure/high velocity oxygen fuel torch to apply the hardfacing to the shirttail portion.

Abstract: The present invention provides a bit with cutting structures or inserts that include diamond particles, in which the diamond-impregnated inserts are surrounded by substantially diamond-free support members. The diamond-impregnated inserts are manufactured separately from the bit body. Once formed, the diamond-impregnated inserts are affixed to the substantially diamond-free support members on bit body by brazing or other means of attachment. The total thermal exposure of the diamond particles during manufacture in accordance with the present invention is significantly lower than the total manufacturing-related thermal exposure in previously known diamond-impregnated cutting structures. Furthermore, the substantially diamond-free support members allow the bit to continue cutting through a formation without an increased contact area, as experienced by bits with diamond-impregnated ribs. Thus, the operating life of the cutting structures, and therefore the life of the bit itself, is increased.

Abstract: A method of forming a tooth rock bit is disclosed. In one embodiment, the method includes attaching the at least one cutting element to a surface of a cone, and depositing a hard facing layer on at least one cutting element prior to the attaching.

Abstract: A drill bit including a bit body having at least one roller cone rotatably coupled to the bit body with a plurality of milled teeth formed on the at least one roller cone is disclosed. At least one milled tooth is arranged so as to form a gage row milled tooth, and the gage row milled tooth includes hardfacing thereon. A cutting element insert is mounted in a gage face of the gage row milled tooth. A method of forming a drill bit structure, the method including machining at least one hole in a preselected location on a gage surface of at least one milled tooth, positioning a plug in the at least one hole, applying a hardfacing material to the at least one milled tooth, removing the plug from the at least one hole, and positioning a drilling insert in the at least one hole is also disclosed.

Abstract: Roller cone drilling wherein the bit optimization process equalizes the downforce (axial force) for the cones (as nearly as possible, subject to other design constraints). Bit performance is significantly enhanced by equalizing downforce.

Abstract: A cutting element for a drill bit used in drilling subterranean formations is formed with an internal chamber or passage for the flow of drilling fluid therethrough. The cutting element includes a substrate having at least one internal passage, and prior to attaching a superabrasive table thereto, the at least one internal passage is filled with a removable, substantially incompressible filler material. Attachment or bonding of the superabrasive table to the substrate under high temperature and high pressure is accomplished without significant distortion of the shape and size of the internal passage. The filler material may be a crystalline salt such as sodium chloride or halite, which is removable by dissolution in water, or may be boron nitride or a volcanic material such as Pyrofolyte material which is mechanically removable.

Abstract: The present invention provides a method of making an earth boring drill bit having a superhard polycrystalline diamond or diamond-like element with greatly improved resistance to thermal degradation without loss of impact strength. Collectively called PCD elements, these elements are formed with a binder-catalyzing material in a high-temperature, high-pressure process. The PCD element has a plurality of partially bonded diamond or diamond-like crystals forming at least one continuous diamond matrix, and the interstices among the diamond crystals forming at least one continuous interstitial matrix containing a catalyzing material. The element has a working surface and a body, where a portion of the interstitial matrix in the body adjacent to the working surface is substantially free of the catalyzing material, and the remaining interstitial matrix contains the catalyzing material.

Abstract: A rock drill bit for percussive drilling, especially top hammer drilling, includes a drill head provided with rock removing members. The rock drill bit is provided with a number of external grooves for conducting cuttings, the grooves extending in the axial direction of the rock drill bit. Formed between adjacent grooves are lands which also extend in the axial direction of the rock drill bit. The rock drill bit has a thread for connection of the rock drill bit to a drill rod. Rear end portions of at least some of the lands define retrac teeth. Each retrac tooth has at least one cutting edge. At least some of the lands comprise a chip surface and a clearance surface that form therebetween an edge angle not greater than 100°.

Abstract: A rotary-type earth-boring drag bit with cutters oriented at varied rake angles and methods for designing such drag bits. Specifically, cutters that are located sequentially adjacent radial distances from a longitudinal axis of the drill bit have cutting faces that are oriented at rake angles that differ from one another. These cutters may be located on the same blade of the drag bit or on different blades of the drag bit. The rake angles at which the cutting faces of these cutters are oriented may be based, at least in part, on the relative radial distances these cutters are spaced from the longitudinal axis of the drag bit, on the vertical positions of these cutters along the longitudinal axis of the drag bit, or in response to actual or simulated evaluations of the use of the drag bit to drill a subterranean formation.

Abstract: New cutting structures for roller cone drill bits are disclosed. In one aspect, a drill bit includes a bit body, roller cones attached to the bit body and able to rotate with respect to the bit body, and a plurality of cutting elements disposed on each of the roller cones, such that axial force on the bit during drilling is substantially balanced between the cones. In another aspect, a drill bit includes a plurality of cutting elements disposed on each roller cone such that the amount of work performed by each cone during drilling is substantially the same as the amount of work performed by each of the other cones. In yet another aspect, a drill bit includes a plurality of cutting elements disposed on each roller cone such that distribution of axial force on the bit is optimized. Additional aspects of the invention are also disclosed.

Abstract: A rotary-type earth-boring drag bit with cutters oriented at varied rake angles and methods for designing such drag bits. Specifically, cutters that are located sequentially adjacent radial distances from a longitudinal axis of the drill bit have cutting faces that are oriented at rake angles that differ from one another. These cutters may be located on the same blade of the drag bit or on different blades of the drag bit.

Abstract: Disclosed are a variety of arcuate-shaped inserts for drill bits, and in particular, for placement in rolling cone cutters of drill bits. The arcuate inserts include 360 degree or ring-shaped inserts, as well as inserts of smaller arcuate length. The arcuate inserts may include stress relieving discontinuities such that, upon assembly into the cone, the arcuate inserts fragment in a controlled and predicted manner into shorter arcuate lengths. The arcuate inserts are suitable for use in all surfaces of the rolling cone cutter, and in other locations in drill bits, and may have specialized cutting surfaces and material enhancements to enhance their cutting duty performance.

Abstract: A percussive rock drill bit includes a head portion with a forward surface surrounded by a peripheral surface. The peripheral surface supports a wreath of peripheral buttons. Front buttons are mounted to the forward surface inside the wreath of peripheral buttons. The button shave a diameter (D) and a height (H), wherein H/D<1.2. The buttons are welded to an essentially flat part of the forward surface whereby the buttons are metallurgically bound to the head portion.

Abstract: A method of fabricating the drill bit includes employing known layered-manufacturing techniques to fabricate the bit crown, positioning a bit gage mold adjacent the bit crown, and disposing a core material within an interior of the bit crown and a cavity of the bit gage mold. A mold that may be employed to fabricate the drill bit includes an initially conforming mold region, in which the prefabricated bit crown may be disposed, and a second, substantially rigid mold region including a cavity to define the gage of the drill bit. Preferably, the conforming mold region is formed of a nonwettable, granular material.

Abstract: The cutting element including a cutting element for a drill bit used in drilling subterranean formations is formed with an internal chamber or passage for the flow of drilling fluid therethrough. A substrate having at least one internal passage, and prior to attaching a superabrasive table thereto, the at least one internal passage is filled with a removable substantially incompressible filler material. Attachment or bonding of the superabrasive table to the substrate under high temperature and high pressure is accomplished without significant distortion of the shape and size of the internal passage. The filler material may be a crystalline salt such as sodium chloride or halite, which is removable by dissolution in water, or may be boron nitride or a volcanic material such as Pyrofolyte material which is mechanically removable.

Abstract: Hardfacing is deposited on a PDC-equipped steel body rotary drag bit and forms substantially protruding structural elements, such as wear knots or chip breakers. Hardfacing may also be applied to features such as gage pads, wherein at least two different hardfacing compositions are utilized and specifically located in order to exploit the material characteristics of each type of hardfacing composition employed. The use of multiple hardfacing compositions may further be employed as a wear-resistant coating on various elements of the drill bit. The surfaces to which hardfacing is applied may include machined slots, cavities or grooves providing increased surface area for application of the hardfacing. Additionally, such surface features may serve to effect a desired residual stress state in the resultant hardfacing layer or other structure.

Abstract: The invention is directed to a bi-center drilling tool adapted to fit within and drill through a casing shoe without damage to the surrounding casing. In one embodiment, the tool comprises a bit body having a proximal and a distal end where the distal end defines a pilot bit and an intermediate reamer section, where each the pilot and reamer sections define a bit face including primary and secondary cutting blades and cutting elements disposed on said blades. In this embodiment, the cutting or wear elements disposed on the one or more cutting blades which extend to or are proximate to the pass-through gauge define a selected angle between the line of contact on the cutting or wear elements and the material to be drilled.

Abstract: The present invention provides a superhard polycrystalline diamond or diamond-like element with improved wear resistance. Collectively called PCD elements for the purposes of this specification, these elements are formed with a binder-catalyzing material in a high-temperature, high-pressure (HTHP) process. The diamond material is formed and integrally bonded to a substrate containing the catalyzing material during the HTHP process. The diamond body so formed has a working surface, a plurality of crystals being exposed at the working surface, and wherein the exposed crystals are substantially free of microfractures. The exposed parts of the exposed crystals are of rounded or domed form.

Abstract: A novel drill bit includes a cutting reamer portion that cuts to gage diameter, and a pilot portion that cuts to a radius about 50%-80% of the reamer portion. The pilot portion extends downward from the reamer portion to create a distinct cutting area including pilot. The torque and weight on bit is evenly distributed between said pilot portion and said reamer portion of said drill bit by iterative adjustment of criteria such as backrake, siderake, cutter height, cutter size, and blade spacing.

Abstract: Rock bits comprising wear and fracture resistant surface of this invention include a steel bit body having at least one leg extending therefrom. A steel cone is rotatably disposed on the leg. The steel cone includes a plurality of steel cutting elements that each projecting outwardly a distance therefrom. At least a portion of the cone comprises a wear resistant surface formed from a wear resistant composite material. The wear resistant composite material is made by the process of combining powders selected from the group consisting of carbides, borides, nitrides, carbonitrides, refractory metals, cermets, Co, Fe, Ni, steel, and combinations thereof, to form a material mixture. The material mixture is applied onto a designated surface of the cone, in one form or another, when the cone is in a pre-existing rigid state. Depending on the particular application, the material mixture can be applied in as a slurry to the designated surface of the cone to form a coating thereon.

Abstract: A drill bit including a bit body having at least one roller cone rotatably coupled to the bit body with a plurality of milled teeth formed on the at least one roller cone is disclosed. At least one milled tooth is arranged so as to form a gage row milled tooth, and the gage row milled tooth includes hardfacing thereon. A cutting element insert is mounted in a gage face of the gage row milled tooth. A method of forming a drill bit structure, the method including machining at least one hole in a preselected location on a gage surface of at least one milled tooth, positioning a plug in the at least one hole, applying a hardfacing material to the at least one milled tooth, removing the plug from the at least one hole, and positioning a drilling insert in the at least one hole is also disclosed.

Abstract: A method to design a bi-center drill bit designed to drill out the cement and other material in the casing and then proceed to drill out the full gauge drilling diameter borehole with a diameter greater than the inside of the casing. The bi-center drill bit has a pilot section on the end of the bit body, an eccentric reamer section and a plurality of cutting elements on the pilot section. The design method comprises the steps of: defining a first center of rotation of the pilot section about the longitudinal axis, defining a radius of rotation R1 of the drill bit about the first center of rotation, defining a second center of rotation of the pilot section spaced apart from the first center of rotation by a distance D, defining a radius of rotation R2 of the drill bit about the second center of rotation, and setting the relationship between D, R1 and R2 such that R1 is less than the sum of R2 and D.

Abstract: A method is disclosed for forming a drill bit structure to which a cutting element is to be affixed. The method includes applying a layer of hardfacing material to a basic bit structure, removing the layer of hardfacing material in a location to which the cutting element is to be affixed, and forming an attachment structure at the location. In one embodiment, the removing is performed by electrode discharge machining. In one embodiment, the basic bit structure is a roller cone, and the cutting element is an insert adapted to be interference fit within a socket in the roller cone.

Abstract: A roller cone for a drill bit is disclosed which includes a cone body having a plurality of sockets. An interior portion of at least one of the sockets is treated on an interior surface of the socket to provide a residual compressive stress proximate the interior of the socket to reduce stress cracking. Forms of treating include shot peening, laser shock peening and hammer peening. In one embodiment, the socket is treated over approximately the lower 50 percent of the lateral wall. In another embodiment, the socket is treated on the bottom surface from the lateral wall inward approximately 33 percent of the diameter of the socket. Another aspect of the invention is a roller cone for a drill bit including a cone body having a plurality of sockets formed in the cone. In this aspect, an interior portion of at least one of the sockets is locally annealed on an interior surface of the socket. In one embodiment, the socket is locally annealed over approximately the lower 50 percent of the lateral wall.

Abstract: A roller cone drill bit having selected left hand walk is disclosed. The bit includes a bit body adapted to couple to a drill string, and a plurality of legs depending from the bit body. Each leg has a roller cone rotatably mounted thereon. Each cone includes a plurality of cutting elements thereon. At least one cone has a nose point of its profile displaced radially inward with respect to a nose point of the profile of the other cones. A roller cone drill bit having selected right hand walk is also disclosed. The bit include a bit body adapted to couple to a drill string, and a plurality of legs depending from the bit body. Each leg has a roller cone rotatably mounted thereon, each cone including a plurality of cutting elements thereon defining a profile. At least one cone has a nose point of the profile displaced radially outward with respect to a nose point of the profile of the other cones.

Abstract: A rotary cone bit, having a functionally-engineered surface of this invention, comprises a bit body having at least one leg extending therefrom, and a cone that is rotatably disposed on the leg. The cone typically comprises a plurality of cutting elements that project outwardly therefrom. The cutting elements comprises a cermet material selected from the group consisting of refractory metal carbides, nitrides, borides, carbonitrides and mixtures thereof. A functionally-engineered material is disposed over a surface portion of at least one of the cutting elements to form a wear resistant surface thereon. The wear resistant surface has a hardness that is different than that of the underlying cutting element. The wear resistant surface is provided by forming a conformable material mixture by combining one or more powders selected from the group consisting of cermets, carbides, borides, nitrides, carbonitrides, refractory metals, Co, Fe, Ni, and combinations thereof, with an applying agent.

Abstract: A method for manufacturing drill bits in segments, using a single key which is nowhere concave in its axial profile to position all three segments together for welding; and drill bits so made.

Abstract: A graphite or silicate plug is coated with a refractory metal and positioned in the cutter pocket of a steel bodied bit as molten hardfacing material is applied to the bit surface under high temperature conditions. The refractory metal cooperates with the hardfacing material to act as a wetting agent that draws the hardfacing material into intimate contact with the body of the displacement plug. The plug is removed leaving a composite pocket opening formed by the steel body and the hardfacing material. A PDC cutter inserted into the composite pocket opening closely adheres to the sides of the opening to reduce the gap between the cutter and the hardfacing material to hereby minimize the effects of erosion in the area of the gap. The wetting material on the displacement plug permits the hardfacing material to flow into and remain in position immediately adjacent the displacement body and in the small surface area between adjacent cutter pockets.

Abstract: Using inserts which are welded in place allows the use of hardfacing in the immediate vicinity of the inserts. Areas of high wear, such as cutting structures and gage areas, can use a combination of ultra-hard inserts with hardfacing for protection against wear. The inserts slows wear, while the hardfacing prevents erosion around the inserts.

Abstract: The present invention provides a cutting element having a cylindrical body having a canted end face on which is formed a ultra hard material layer and a method of forming the same. One or a plurality of transition layers may be provided between the ultra hard material layer and the cutting element body.

Abstract: A method of forming a drill bit structure, the method including fixing spacers to the drill bit structure. The spacers are arranged at preselected locations on an outer surface of the drill bit structure. A hardfacing material is then applied to the drill bit structure, and the spacers are removed. Holes are machined in the drill bit structure at the preselected locations, and drilling inserts are positioned in each hole.

Abstract: A drill bit for use in drilling operations in a wellbore, the drill bit having a bit body including a plurality of bit legs, each supporting a rolling cone cutter; a coupling member formed at an upper portion of the bit body; at least one temperature sensor for monitoring at least one temperature condition of the improved drill bit during drilling operations; and at least one temperature sensor cavity formed in the bit body and adapted for receiving, carrying, and locating the at least one temperature sensor in a particular position relative to the bit body which is empirically determined to optimize temperature sensor discrimination.

Abstract: The cutting plate for a drill bit is press-formed from a powdery starting material. In the process, the cutting plate is arranged horizontally in the press die and the relative movement of top punch and bottom punch with respect to the die is effected parallel to the flank or flanks of the lateral supporting edge or edges. The novel method enables a variety of special design configurations of the cutting plates.

Abstract: A novel and improved roller cone drill bit and method of design are disclosed. A roller cone drill bit for drilling through subterranean formations having an upper connection for attachment to a drill string, and a plurality cutting structures rotatably mounted on arms extending downward from the connection. A number of teeth are located in generally concentric rows on each cutting structure. The actual trajectory by which the teeth engage the formation is mathematically determined. A straight-line trajectory is calculated based on the actual trajectory. The teeth are positioned in the cutting structures such each tooth having a designed engagement surface is oriented perpendicular to the calculated straight-line trajectory.

Abstract: To eliminate or reduce the possibility of fracture in drill steels used in the roof bolting operations in mines the square or hexagonal surfaces of such drill steels or the elements such as couplings or collars which are to be connected to them are machined rather than forged.

Abstract: A roller cone drill bit for drilling earth formations is disclosed. The bit includes a bit body and a plurality of roller cones attached to the bit body and able to rotate with respect to the bit body. The drill bit includes plurality of cutting elements disposed on each of the roller cones such that at least one of the cutting elements includes a step shaped crest on its outer surface. In one embodiment, the step shaped crest includes a difference in extent between a more extensive and less extensive crest segment selected to correspond to a penetration depth in a particular earth formation at which fracture failure is expected. Other embodiments include one or more flank surfaces having more and less extensive surfaces thereon corresponding to the more and less extensive crest segments.

Abstract: A method for optimizing drilling performance of a roller cone drill bit is disclosed. The method includes simulating drilling with the bit in a selected earth formation to determine at least one drilling performance parameter. The orientation of at least one non-axisymmetric cutting element on the bit is adjusted and the simulating the drilling and determining the at least one performance parameter are repeated. The adjusting and simulating the drilling are repeated until the at least one performance parameter is determined to be at an optimum value. In one embodiment, the performance parameter includes rate of penetration.