Patent Application
20080289880
The invention pertains to a fixed cutter bit, as well as a blade for a fixed cutter bit, and the methods for making the same, that is useful in drilling boreholes in subterranean formations such as is common in oil and gas exploration. More specifically, the invention pertains to a fixed cutter bit, as well as a blade for a fixed cutter bit, and the methods for making the same, that is useful in drilling boreholes in subterranean formations wherein the fixed cutter bit contains blades that exhibit improved wear resistance and toughness.
Earth-boring bits may have fixed or rotatable cutting elements. Earth-boring bits with fixed cutting elements typically include a bit body machined from steel or fabricated by infiltrating a bed of hard particles, such as cast carbide (WC+W2C), tungsten carbide (WC), and/or sintered cemented carbide with a binder such as, for example, a copper-base alloy. Several cutting inserts are fixed to the bit body in predetermined positions to optimize cutting. The bit body may be secured to a steel shank that typically includes a threaded pin connection by which the bit is secured to a drive shaft of a downhole motor or a drill collar at the distal end of a drill string.
Steel bodied bits are typically machined from round stock to a desired shape, with topographical and internal features. Hard-facing techniques may be used to apply wear-resistant materials to the face of the bit body and other critical areas of the surface of the bit body.
In the conventional method for manufacturing a bit body from hard particles and a binder, a mold is milled or machined to define the exterior surface features of the bit body. Additional hand milling or clay work may also be required to create or refine topographical features of the bit body.
Once the mold is complete, a preformed bit blank of steel may be disposed within the mold cavity to internally reinforce the bit body and provide a pin attachment matrix upon fabrication. Other sand, graphite, transition or refractory metal based inserts, such as those defining internal fluid courses, pockets for cutting elements, ridges, lands, nozzle displacements, junk slots, or other internal or topographical features of the bit body, may also be inserted into the cavity of the mold. Any inserts used must be placed at precise locations to ensure proper positioning of cutting elements, nozzles, junk slots, etc. in the final bit.
The desired hard particles may then be placed within the mold and packed to the desired density. The hard particles are then infiltrated with a molten binder, which freezes to form a solid bit body including a discontinuous phase of hard particles within a continuous phase of binder.
The bit body may then be assembled with other earth-boring bit components. For example, a threaded shank may be welded or otherwise secured to the bit body, and cutting elements or inserts (typically cemented tungsten carbide, or diamond or a synthetic polycrystalline diamond member (“PDC”)) are secured within the cutting insert pockets, such as by brazing, adhesive bonding, or mechanical affixation. Alternatively, the cutting inserts may be bonded to the face of the bit body during furnacing and infiltration if thermally stable PDC's (“TSP” (thermally stable polycrystalline diamond)) are employed.
Fixed cutter bits have been used in drilling boreholes in subterranean formations such as is common in oil and gas exploration. United States Patent Application Publication No. US2005/0133272 to Huang et al., U.S. Patent Application Publication No. US2005/0247491 to Mirchandani et al., U.S. Pat. No. 6,615,934 to Mensa-Wilmot, and U.S. Pat. No. 7,096,978 to Dykstra et al. show exemplary fixed cutter bits, and these patent documents are hereby incorporated by reference herein. One typical kind of fixed cutter bit includes blades that extend or project from the main body of the cutter bit. The blades typically carry a plurality of cutter elements wherein the cutter elements impinge the earth formation during the drilling operation.
Earth-boring bits typically are secured to the terminal end of a drill string, which is rotated from the surface or by mud motors located just above the bit on the drill string. Drilling fluid or mud is pumped down the hollow drill string and out nozzles formed in the bit body. The drilling fluid or mud cools and lubricates the bit as it rotates and also carries material cut by the bit to the surface.
The bit body and other elements of earth-boring bits are subjected to many forms of wear as they operate in the harsh down hole environment. Among the most common form of wear is abrasive wear caused by contact with abrasive rock formations. In addition, the drilling mud, laden with rock cuttings, causes erosive wear on the bit.
The service life of an earth-boring bit is a function not only of the wear properties of the PDCs or cemented carbide inserts, but also of the wear properties of the bit body (in the case of fixed cutter bits) or cones (in the case of roller cone bits). One way to increase earth-boring bit service life is to employ bit bodies or cones made of materials with improved combinations of strength, toughness, and abrasion/erosion resistance.
Since the blades that carry the cutter elements experience (or can experience) a significant amount of abrasive wear during the drilling operation due to the abrasive nature of a typical earth formation. Thus, it would be highly desirable to provide a fixed cutter bit, as well as a method for making such a fixed cutter bit, that is useful in drilling boreholes in subterranean formations wherein the fixed cutter bit contains blades that exhibit improved wear resistance, and this is especially the case with respect to the leading edge or region of the blade.
Since the blades that carry the cutter elements experience (or can experience) a significant amount of impact during the drilling operation due to the inconsistent nature of a typical earth formation in that it contains hard inclusions (e.g., rock). Thus, it would be highly desirable to provide a fixed cutter bit, as well as a method for making such a fixed cutter bit, that is useful in drilling boreholes in subterranean formations wherein the fixed cutter bit contains blades that exhibit improved impact resistance.
Fluid emitted from the nozzles in the bit body can directly impinge upon the cutter bit body including impingement upon the blades that carry the cutter elements. During the drilling operation, the blades, which carry the cutter elements, experience (or can experience) a significant amount of erosive wear. This erosive wear can be due to the impingement of the fluid, as well as the abrasive nature of a typical earth formation. Thus, it would be highly desirable to provide a fixed cutter bit, as well as a method for making such a fixed cutter bit, that is useful in drilling boreholes in subterranean formations wherein the fixed cutter bit contains blades that exhibit improved erosive wear resistance.
In one form thereof, the invention is a blade for use on a tool that impinges earth strata. The blade comprises a blade body that has a leading surface. The blade body has a first portion that defines at least a part of the leading surface. The blade body further has a second portion. The first portion comprises a first material composition and the second portion comprises a second material composition.
In another form thereof, the invention is a blade for use on a fixed cutter bit. The blade comprises a blade body that has a leading portion, optionally a mediate portion and a trailing portion. The leading portion contains at least one groove for receiving a cutter element. The leading portion is made from a leading portion material, the mediate portion being made from a mediate portion material, and the trailing portion being made from a trailing portion material.
In still another form thereof, the invention is a fixed cutter bit that has a bit body that presents a shoulder wherein a blade projects from the shoulder. The blade comprises a blade body that has a leading surface. The blade body has a first portion defining at least a part of the leading surface, and the blade body further has a second portion. The first portion comprises a first material composition and the second portion comprises a second material composition. The first material composition material is selected from the group consisting of cemented carbide and steel and a hard composite comprising a plurality of hard constituents and matrix powder of hard particles and an infiltrant alloy bonded together to form the hard composite. The second material composition material is selected from the group consisting of cemented carbide and steel and a hard composite comprising a plurality of hard constituents and matrix powder of hard particles and an infiltrant alloy bonded together to form the hard composite.
In yet another form thereof, the invention is a fixed cutter bit for impinging earth strata. The fixed cutter bit comprises a bit body that has a first portion of a first hardness and a plurality of blades projecting from the bit body wherein each one of the blades comprises a blade body and at least one cutter element carried by the blade body. Each one of the blade bodies has a portion of a second hardness greater than the first hardness.
The following is a brief description of the drawings:
Referring to the drawings,
As illustrated in
The bit body 22 presents at least a portion thereof that is of a first hardness. The blades have at least a portion thereof that is of a second hardness. The second hardness of the portion of the blade is greater than the first hardness of the portion of the bit body.
In this specific embodiment, the leading portion 44 of the blade 40 comprises cemented carbide (e.g., cemented (cobalt) tungsten carbide) and the trailing portion 46 of the blade 40 comprises steel. The leading portion 44 and trailing portion 46 can be joined together by any one of a number of techniques including without limitation brazing techniques and infiltration techniques. Although it will be discussed in more detail hereinafter, the blade 40 is joined at the radial inward edge 48 thereto the cutter bit body by any one of a number of techniques including without limitation brazing techniques, infiltration techniques, press fitting techniques, shrink fitting techniques, welding techniques, and mechanical technical techniques (e.g. mechanical fastening). The end result is that the blade is securely affixed to the cutter bit body.
It is contemplated that an embodiment of the blade that has only a leading portion and a trailing portion may utilize steel as a material for the portions. In this regard, as one alternative, the leading portion may be made from steel and the trailing portion made from cemented carbide. As another alternative, the leading portion may be made from cemented carbide and the trailing portion made from steel. As yet another alternative, the leading portion may be made from steel and the trailing portion made from the hard component-matrix composite material. As still another alternative, the leading portion may be made from the hard component-matrix composite material and the trailing portion made from steel.
The leading portion 84 of the blade 80 comprises cemented carbide. The mediate portion 86 of the blade 80 comprises a hard component-matrix composite material. The trailing portion 88 of the blade 80 comprises steel. For this embodiment, the leading portion, the mediate portion and the trailing portion can be joined together by any one of a number of techniques including without limitation brazing techniques and infiltration techniques. Although it will be discussed in more detail hereinafter, the blade 80 is joined at the radial inward edge 89 thereto the cutter bit body by any one of a number of techniques including without limitation brazing techniques, infiltration techniques, press fitting techniques, shrink fitting techniques, welding techniques and mechanical technical techniques (e.g. mechanical fastening). The end result is that the blade is securely affixed to the cutter bit body.
Blade 100 has a radial inward portion 107 at the radial inward edge 109 thereof. The radial inward portion 107 is infiltrated tungsten metal and is particularly useful in facilitating the joinder of the blade 100 to the cutter bit body, especially when techniques that create a metallurgical bond are the bonding techniques. It should be appreciated that any of the other blade structures could include a radial inward portion that comprises infiltrated tungsten metal. It should also be appreciated that blade 100 could be affixed to the cutter bit body by any one of a number of techniques including without limitation brazing techniques, infiltration techniques, press fitting techniques, shrink fitting techniques, welding techniques, and mechanical technical techniques (e.g. mechanical fastening). The end result is that the blade is securely affixed to the cutter bit body.
As shown in
The seventh specific embodiment of the blade 200 provides a replacability (or repairability) feature for the blade 200. During a cutting or drilling operation, one or more (but not all of the separate portions (204, 206208) of the blade 200 may become damaged to such an extent that replacement of the damaged portions is necessary. This embodiment permits replacement of only the damaged portion(s).
Replacement of only the damaged portion(s) can be accomplished by first detaching the blade 200 from the bit body. The complexity of detaching the blade 200 from the bit body can vary depending upon the manner of attachment between the blade and the bit body. Once the blade 200 is detached from the bit body, the bolts 220 are loosened so that the separate leading, mediate and trailing portions are detached from each other. The damaged portion(s) is replaced with an undamaged portion. The separate portions are the aligned and the bolts engaged the threaded bore and are tightened so as to cause the portions to press very tightly against each other.
The ability to replace a portion of the blade also exists for those blades in which the portions are joined together in such a fashion (e.g., brazing) so as to permit the disassembly of the portions. When a portion of a blade like the blade 60 in
The ability or capability to replace only a portion (e.g., the damaged portion(s)) of the blade body should reduce the overall operating costs because only a portion of the, and not the entire, blade is replaced. The ability to replace only a selected portion of the blade allows for the customization of the blade (even during the course of the drilling operation) to optimize performance. In this regard, of during the drilling (or cutting) operation one portion of the blade experiences undue or excessive wear or failure because of material selection, the damaged portion can be replaced by a corresponding portion made of a material more suitable to the specific drilling/cutting application or working environment. The replaceability or repairability feature thus serves to decrease the overall operating costs via a decrease in the cost of repair and the increase in operational performance.
As mentioned above, there are a number of ways to attach or affix the blade to the cutter bit body. These methods include without limitation brazing techniques, infiltration techniques, press fitting techniques, shrink fitting techniques and welding techniques.
More specifically,
Blade 300 can be considered to present a leading region (see bracket 320) that comprises pieces 302, 304 and 306. The leading region 320 carries the cutter elements. More particularly, piece 302 contains grooves 322 that receive the polycrystalline diamond cutter elements 324. The leading portion 320 typically experiences the greatest degree of abrasive wear because it carries the cutter elements that first impinge the earth strata.
The pieces (302-306) that comprise the leading region 320 typically are made from a material that exhibits a higher hardness than the other pieces that comprise the blade 300 because it experiences more abrasive wear. However, there may be specific applications that cause the wear to be uneven or unequal between the pieces (302-306) that comprise the leading region 320. In such a situation, it may prove to be beneficial to make the different pieces (302-306) from different kinds of materials or different compositions of the same basic material. By doing so, the wear of the pieces (302-306) may be more even, and thus, extend or optimize the overall life of the tool or bit.
Blade 300 also presents a mediate region (see bracket 328) that comprises pieces 308, 310 and 312. The mediate region 328 typically does not experience as much wear as does the leading region 320 or even the trailing region 330 (as described hereinafter). As a result, the mediate region 328 is best suited to comprise pieces that are made from material that absorbs impact forces during the drilling or cutting operation. In other words, the pieces 308-312 are made from impact-resistant materials. As mentioned in connection with the description of the leading region 320, there may be instances where the wear of the pieces (308-312) is unequal. In such a circumstance, the material from which each piece (308-312) is made can be selected so that the wear or performance is more equal.
Blade 300 also presents a trailing region (see brackets 330). Trailing region 330 comprises pieces 314, 316 and 318. The pieces (314-318) that comprise the trailing region 330 typically are made from a material that exhibits a higher hardness than the pieces in the mediate region 328, but equal to or even lower than the pieces that comprise the leading region 300. While the trailing region experiences more wear than does the mediate region, it typically experiences less wear than the leading region. There may be specific applications that cause the wear to be uneven or unequal between the pieces (314-318) that comprise the trailing region 330. In such a situation, it may prove to be beneficial to make the different pieces (314-318) from different kinds of materials or different compositions of the same basic material. By doing so, the wear of the pieces (314-318) may be more even, and thus, extend or optimize the overall life of the tool or bit.
It should be appreciated that the material selection parameters for the blade 300 may be such that the material differs in a radial direction. More specifically, the pieces 302, 308 and 314 may comprise one kind of material (e.g., cemented carbide). The middle row of pieces 304, 310 and 316 may comprise another kind of material such as, for example, the hard composite material or steel. The bottom row of pieces 306, 312 and 318 may comprise still another kind of material or a material (e.g., the hard composite material) like the material of the above rows. Again it is emphasized that there is a wide range of possibilities when it comes to material selection and material positioning of the pieces. Such a wide range of possibilities for the material selection ad positioning provides the ability to customize the blade to a particular drilling or cutting application.
Referring to
Portion 676 is made from a hard composite material. While portion 676 is shown as comprising a single piece, it should be appreciated that portion 676 may comprise a plurality of pieces or segments that are joined together. Portion 678 is made from steel. Again, like for portion 676, while portion 678 is shown as comprising a single piece, it should be appreciated that portion 678 may comprise a plurality of pieces or segments that are joined together. Blade 668 has a leading surface 680, a trailing surface 682, a top (or radial outward) surface 684 and a bottom (or radial inward) surface 686.
In the embodiments such as illustrated in
A part of the groove 706 is in portion 692 and the other part of the groove is in the selected tiles. In the case of the specific embodiment of
The compositional aspects of the various portions of the blades may vary depending upon the specific drilling application. In this respect, it should be appreciated that changes in the composition or microstructure of the material results in changes in the properties of the material. For example, while there can be exceptions based upon other compositional factors, generally speaking, a decrease in the cobalt content of a cemented (cobalt) tungsten carbide material typically results in a higher hardness (as well as higher abrasion resistance and erosion resistance) and a lower toughness. An increase in the cobalt content of a cemented (cobalt) tungsten carbide material typically results in a lower hardness (as well as lower abrasion resistance and erosion resistance) and a higher toughness. The grain size of the tungsten carbide also impacts the hardness in that a smaller or finer grain size typically results in a harder material with all other parameters remaining the same. Further, it should be appreciated that different materials provide different properties (e.g., hardness, abrasion resistance, erosion resistance, and toughness). For example, generally speaking, steels typically exhibit a lower hardness, but higher toughness than do cemented carbides. The ability to vary the compositional aspects of the portions of the blades allows for the customization of the blades to suit specific drilling conditions including specific earth formations. As will become apparent, the material from which the blades are made is selected from the group consisting of (a) cemented carbide, and (b) steel, and (c) a hard composite comprising a plurality of hard constituents and matrix powder of hard particles and an infiltrant alloy bonded together to form the hard composite.
In reference to the composition of the cemented tungsten carbide, the cemented tungsten carbides may be any one of a number grades of cemented tungsten carbide that are suitable for borehole drilling operations. These cemented tungsten carbide grades may include grades that comprise between about 0.01 weight percent and about 35 weight percent cobalt with the balance tungsten carbide (the average grain size varies between about 0.01 microns and about 25 microns) and recognized impurities. These cemented tungsten carbide grades may also include grades that comprise between about 0.01 weight percent and about 35 weight percent cobalt, various additives (e.g., the carbides, nitrides and/or carbonitrides of the elements (except for tungsten) of Group IVa, Va, and VIa of the Periodic Table) with the balance tungsten carbide (the average grain size varies between about 0.01 microns and about 25 microns), and recognized impurities. Another compositional range of the cemented (cobalt) tungsten carbide is a cobalt content between about 6 weight percent and about 25 weight percent with the balance tungsten carbide (average grain size between about 2 microns to about 12 microns) and recognized impurities.
Preferred grades of cemented tungsten carbide comprise the following exemplary compositions of cemented (cobalt) tungsten carbide (without limitation): (A) about 6 weight percent cobalt with the balance tungsten carbide (average grain size ranging between about 2 microns to 6 microns) and recognized impurities, and having a hardness equal to 90.0-91.5 Rockwell A and a fracture toughness equal to between about 8 and about 14 MPa·m1/2; (B) about 10 weight percent cobalt with the balance tungsten carbide (average grain size ranging between about 2 microns to 8 microns) and recognized impurities, and having a hardness equal to 87.0-89.0 Rockwell A and a fracture toughness equal to between about 10 and about 17 MPa·m1/2; (C) about 12 weight percent cobalt with the balance tungsten carbide (average grain size ranging between about 4 microns to 12 microns) and recognized impurities; about 13-14 weight percent cobalt with the balance tungsten carbide (average grain size ranging between about 2 microns to 6 microns) and recognized impurities, and having a hardness equal to 87.5-89.5 Rockwell A and a fracture toughness equal to between about 10 and about 17 MPa·m1/2; about 16 weight percent cobalt with the balance tungsten carbide (average grain size ranging between about 4 microns to 10 microns) and recognized impurities, and having a hardness equal to 85.0-87.0 Rockwell A and a fracture toughness equal to between about 12 and about 20 MPa·m1/2; and about 20 weight percent cobalt with the balance tungsten carbide (average grain size ranging between about 2 microns to 4 microns) and recognized impurities, and having a hardness equal to 84.5-86.5 Rockwell A and a fracture toughness equal to between about 14 and about 24 MPa·m1/2. The fracture toughness is measured according to the ASTM Standard B771 B771-87(2001) Standard Test Method for Short Rod Fracture Toughness of Cemented Carbides.
Another suitable grade of cemented (cobalt) carbide has a composition of up to 0.25 weight percent cobalt with the balance tungsten carbide that has an average grain size less than or equal to about 1 micron and recognized impurities. Other grades of cobalt-bonded cemented carbides (and their properties) are disclosed in the article by Santhanam et al., entitled “Cemented Carbides” Metals Handbook Volume 2, 10th Edition Properties and Selection, wherein this article is hereby incorporated in its entirety by reference herein. The ability to vary the compositional aspects of the cemented carbide portions of the blades allows for the customization of the blades to suit specific drilling conditions including specific earth formations.
In reference to the composition of the steel used as a portion of the blades, it is contemplated that many different steel compositions are suitable. Broadly speaking, these steel compositions may include low alloy steels, alloy steels boron alloy steels, and air hardened steels.
Particularly suitable steel compositions include the following: AISI 4140 steel and AISI 316 stainless steel. The nominal composition (in weight percent) for the AISI 4140 steel is: 0.38-0.43% carbon, 0.75-1.00% manganese, 0.035% phosphorous, 0.040% sulfur, 0.15-0.35% silicon, 0.80-1.10% chromium, 0.15-0.25% molybdenum and the balance iron. The nominal composition (in weight percent) for 316 stainless steel is: maximum carbon 0.08%, maximum manganese 2.00%, maximum phosphorous 0.030%, maximum silicon 0.030%, 10.00-16.00% nickel, 16.00-18.00% chromium, 2.00-3.00% molybdenum, and the balance iron. It is contemplates that other stainless steel compositions may also be suitable wherein these include austenitic stainless steels because of their high wear and impact resistance from room temperature down to cryogenic temperatures. Of the austenitic stainless steels, AISI types 301, 302, 304 and 304L grades appear to be suitable. In addition to the above steels, the following steels are also suitable: Grade 1020 steel with a composition (in weight percent) of 0.18%-0.23% carbon, 0.3%-0.6% manganese, 0.05 maximum sulfur, 0.05 maximum phosphorous, and the balance iron; Grade 8740 steel with a composition (in weight percent) of 0.38%-0.43% carbon, 0.75%-1.0% manganese, 0.4%-0.6% chromium, 0.4%-0.7% nickel, 0.2%-0.3% molybdenum, 0.15%-0.035% silicon, 0.05 maximum sulfur, 0.05 maximum phosphorous, and the balance iron; Grade 15B37 steel with a composition of 0.30%-0.39% carbon, 1.0%-1.5% manganese, 0.0005-0.003% boron, 0.037-0.05 titanium, 0.05 maximum sulfur, 0.05 maximum phosphorous, and the balance iron; Grade 4715 steel with a composition (in weight percent) of 0.13-0.18% carbon, 0.7-0.9% manganese, 0.45-0.65% chromium, 0.7-1.0% nickel, 0.45-0.65% molybdenum, 0.15%-0.035% silicon, 0.035% maximum sulfur, 0.035% maximum phosphorous, and the balance iron; and Grade A7 steel with a composition (in weight percent) of about 2.25% carbon, 0.8% maximum manganese, 5%-5.75% chromium, 0.7-1.0% nickel, 0.9-1.4% molybdenum, 0.15%-5% silicon, 0.035% maximum sulfur, 0.035% maximum phosphorous, 3.9-5.2% vanadium, 0.5-1.5% tungsten and the balance iron.
It should be appreciated that the composition and microstructure of the steel grades can impact the properties useful to the performance of the blade in a drilling or cutting application. Like for the cemented carbides, the hardness, toughness, erosion resistance and abrasion resistance are properties of the steel that impact upon the performance of the blade during use. As can also be appreciated, the composition and microstructure of steels can vary to a great extent so that the portions of the blades made from steel can exhibit a wide variety of properties to accommodate a wide variety of drilling or cutting applications. In this regard, the treatment of the steel can impact the properties even though the chemical composition remains essentially the same. Databases such as, for example, MatWeb.com on the internet, provide properties for a wide variety of steels.
Although not described as a specific embodiment, it should be appreciated that the portion(s) of the blades that are described as being made of steel could also be made from other ferrous and non-ferrous alloys. These portions could comprise a casting having hard particles therein or white cast iron. Whatever the material of these portions, it is beneficial if the material possesses properties so that it is bondable with an infiltrant alloy when bonded to a hard component-matrix composite material. It is also beneficial if the steel material is brazable with the cemented tungsten carbide portion. The ability to vary the compositional aspects of the steel portions (or the other ferrous and non-ferrous portions) of the blades allows for the customization of the blades to suit specific drilling conditions including specific earth formations.
In reference to the composition of the hard component-matrix composite material portion of the blades, the compositions set forth in U.S. Pat. No. 6,984,454 to Majagi entitled WEAR-RESISTANT MEMBER HAVING A HARD COMPOSITE COMPRISING HARD CONSTITUENTS HELD IN AN INFILTRANT MATRIX, that is assigned to Kennametal Inc., are especially suitable for use as the hard component-matrix composite material portion of the blades. U.S. Pat. No. 6,984,454 to Majagi is hereby incorporated by reference herein.
In reference to the hard component-matrix composite material, it comprises a plurality of discrete hard constituents (described hereinafter) wherein these hard constituents are held within a matrix. The matrix comprises a mass of matrix powder that comprises different kinds of hard particles and/or powders, and an infiltrant alloy that has been infiltrated into the mass of the matrix powder and the hard constituents under the influence of heat and sometimes under additional environmental influences such as, for example, in a pressure or in a vacuum. Furthermore, the infiltrant alloy may be infiltrated into the mass of hard constituents and matrix powder under various atmospheres (e.g., argon, helium, hydrogen, and nitrogen).
The hard constituents may comprise sintered cemented carbide members (which hereinafter may be called sintered cemented carbide members) that can be of various geometric shapes such as, for example, triangular. The hard constituent presents a specific pre-determined shape. This shape can vary depending upon the specific application for the tough wear-resistant hard member. Powder metallurgical techniques allow for the shape of the sintered cemented carbide member to take on any one of a number of shapes or geometries. In one alternative, it is contemplated that the hard constituents are of a size so as to have a surface area that ranges between about 0.001 square inches (0.006 square centimeters) and about 16 square inches (103 square centimeters) on each exposed surface (or facet) of the sintered cemented carbide member. In this regard, for example, the sintered cemented carbide member may have a plurality of exposed surfaces wherein one exposed surface has a hard constituent that occupies between about 0.006 square centimeters and about 103 square centimeters of surface area and another exposed surface that has a hard constituent that occupies between about 0.006 square centimeters and about 103 square centimeters of surface area. It is also contemplated that the sintered cemented carbide member may be of a size that ranges between about 0.005 square inches (0.03 square centimeters) and about 5 square inches (33 centimeters). It is further contemplated that the sintered cemented carbide member may be of a size that ranges between about 0.0005 square inches (0.003 square centimeters) and about 0.5 square inches (0.003 centimeters).
It is further contemplated that the sintered cemented carbide member may be of a size so as to present one or more exposed surfaces wherein each exposed surface has a hard constituent that occupies between about 5 square inches (32.35 square centimeters) and about 225 square inches (1451.59 square centimeters). Alternate ranges of the surface area of the hard constituent on each exposed surface can be in one instance between about 25 square inches (161.29 square centimeters) and about 200 square inches (1290.3 square centimeters), in another instance between about 50 square inches (322.58 square centimeters) and about 150 square inches (96.68 square centimeters), in another instance between about 75 square inches (483.87 square centimeters) and about 125 square inches (801.39 square centimeters) and in still another instance between about 50 square inches (322.58 square centimeters) and about 110 square inches (709.61 square centimeters).
As an alternative, a hard sintered cemented carbide member could be crushed to obtain hard constituents wherein the hard constituents are crushed particles of a larger size wherein the particle size is measured by mesh size (e.g., −80+120 mesh).
The hard constituents are selectively positioned within the matrix of the hard composite which typically occurs in the mold prior to infiltration. It is contemplated that the hard constituents may cover between about 0.5 percent to about 90 percent of the surface area of the wear-resistant hard member. Applicant does not intend to restrict the invention to the specific positioning of the hard constituents in the hard composite. For example, the hard constituents may be uniformly (or non-uniformly or randomly) distributed throughout the volume of the hard composite.
One composition of the sintered cemented carbide member 34 is cobalt cemented tungsten carbide wherein the cobalt ranges between about 0.2 weight percent and about 6 weight percent of the cobalt cemented tungsten carbide member and tungsten carbide is the balance of the composition. Another composition for the sintered cemented carbide member 34 is cobalt cemented tungsten carbide wherein the cobalt ranges between about 6 weight percent and about 30 weight percent of the cobalt cemented tungsten carbide member and tungsten carbide is the balance of the composition. In still another composition, the sintered cemented carbide member may comprise cobalt (10 weight percent cobalt) cemented tungsten carbide.
By mentioning the above specific hard constituent, applicant does not intend the limit the scope of the invention to this specific hard constituent. Applicant contemplates that other materials would be suitable for use as the hard constituents in the hard composite. In this regard, the following materials would appear to be suitable for use as hard constituents in the hard composite: sintered cemented tungsten carbide wherein a binder includes one or more of cobalt, nickel, iron and molybdenum; coated sintered cemented tungsten carbide wherein a binder includes one or more of cobalt, nickel, iron and molybdenum, and the coating comprises one or more of nickel, cobalt, iron and molybdenum; one or more of the carbides, nitrides, and borides of one or more of titanium, niobium, tantalum, hafnium, and zirconium; one or more of the coated carbides, coated nitrides, and coated borides of one or more of titanium, niobium, tantalum, hafnium, and zirconium wherein the coating comprises one or more of nickel, cobalt, iron and molybdenum; chromium carbides; coated chromium carbides; coated silicon carbide wherein the coating comprises one or more of nickel, cobalt, iron and molybdenum; and coated silicon nitride wherein the coating comprises one or more of nickel, cobalt, iron, copper, molybdenum or any other suitable metal; and coated boron carbide wherein the coating comprises one or more of nickel, cobalt, iron, copper, molybdenum, and any other suitable metal.
The matrix powder can comprise a crushed cemented carbide particle. The crushed cemented carbide particles may be present in a size range for these crushed cemented carbide particles equal to −325+200 mesh. Another size range for these crushed cemented carbide particles is −80+325 mesh. The standard to determine the particle size is by using sieve size analysis and the Fisher sub-sieve size analyzer for −325 mesh particles. One composition for the crushed cemented carbide particles is cobalt cemented tungsten carbide wherein the cobalt ranges between about 6 weight percent and about 30 weight percent of the cobalt cemented tungsten carbide material and tungsten carbide is the balance of the material. Another preferred composition for crushed cemented carbide particles is cobalt cemented tungsten carbide wherein the cobalt ranges between about 0.2 weight percent and about 6 weight percent of the cobalt cemented tungsten carbide material and tungsten carbide is the balance of the material.
By mentioning specific compositions, applicant does not intend the limit the scope of the invention to these specific cemented carbides. Applicant contemplates that other cemented carbides (e.g., chromium carbide) would be suitable for use as the crushed cemented tungsten carbide particles in the hard composite. In this regard, the carbides could be different from tungsten carbide (e.g., titanium carbide and chromium carbide) and the binder could be different from cobalt (e.g., nickel). Applicant further contemplates that the crushed cemented carbide particles may vary in composition throughout a particular hard composite depending upon the specific application. Applicant also contemplates that certain hard materials other than cemented carbides may be suitable to form these particles.
The matrix may also contain crushed cast carbide particles wherein one size range for these particles is −325 mesh. Another size range for these particles is −80 mesh. One composition for these particles is cast tungsten carbide. Applicant contemplates that the crushed cast carbide particles may vary in composition throughout a particular hard composite depending upon the specific application. Applicant further contemplates that other cast carbides or hard materials are suitable for use in place or along with the crushed cast carbide particles.
The matrix powder may further include in addition to crushed cemented carbide particles and/or crushed cast carbide particles, any one or more of the following: crushed carbide particles (e.g., crushed tungsten carbide particles that have a size of −80+325 mesh), steel particles that have an exemplary size of −325 mesh, carbonyl iron particles that have an exemplary size of −325 mesh, cemented carbide powder, and coated (e.g., nickel coating) cemented carbide particles, and nickel-coated tungsten carbide particles (−80+325 mesh).
As discussed above, it is desirable that the infiltrant alloy 31 has a melting point that is low enough so as to not degrade the hard constituents upon contact therewith during the infiltration process. Along this line, the infiltrant alloy has a melting point that ranges between about 500 degrees Centigrade and about 1400 degrees Centigrade. Applicant contemplates that the infiltrant alloys may have a melting point that ranges between about 600 degrees Centigrade and about 800 degrees Centigrade. Applicant further contemplates that the infiltrant alloys may have a melting point that ranges between about 690 degrees Centigrade and about 770 degrees Centigrade. Applicant still further contemplates that the infiltrant alloys may have a melting point below about 700 degrees Centigrade. Exemplary general types of infiltrant alloys include copper-based alloys such as, for example, copper-silver alloys, copper-zinc alloys, copper-nickel alloys, copper-tin alloys, and nickel-based alloys including nickel-copper-manganese alloys. Exemplary infiltrant alloys are set forth in Table 1 herein below.
By mentioning specific infiltrant alloys in Table 1, applicant does not intend to limit the scope of the invention to infiltrant alloys with these specific compositions and/or properties. As one alternative, the composition of the infiltrant alloy could be within the range of 5-40 weight percent nickel, 5-40 weight percent manganese and the balance copper.
Referring to a hard component-matrix composite material, the hard particles in the hard composite may comprise 100 percent crushed nickel cemented chromium carbide particles. The nickel could comprise between about 3 weight percent and about 25 weight percent of the cemented carbide with chromium carbide comprising the balance. The preferred composition of the cemented carbide is about 15 weight percent nickel and the balance chromium carbide. The particle size of the crushed cemented (nickel) chromium carbide particles can range between about −325 mesh and about +80 mesh. The infiltrant alloy can comprise between about 60 weight percent and about 80 weight percent of the hard composite and the crushed nickel cemented chromium carbides can comprise between about 20 weight percent and about 40 weight percent of the hard composite.
Referring to another hard component-matrix composite material, it can also be made from the compositions set forth in Table 1A below. The matrix powder is Mixture No. 2 taken from Table 2 hereof. The hard constituents are crushed nickel cemented chromium carbide wherein the nickel is present in an amount of 15 weight percent. The particle size of the crushed cemented (nickel) chromium carbide particles can range between about −325 mesh and about +80 mesh. The titanium diboride (TiB2) particles have a particle size equal to −325 mesh. The infiltrant alloy was the copper-based alloy A-1 set forth in Table 1. The infiltrant alloy comprised between about 60 weight percent and about 70 weight percent of the hard composite.
In yet another embodiment of the hard constituent-matrix composite, there are a plurality of sintered cemented carbide members that typically have a composition of 10 weight percent cobalt and the balance tungsten carbide. The matrix powder typically includes tungsten carbide, chromium carbide, as well as cobalt and nickel in the form of a binder alloy for the carbides and/or a coating on the carbides. One typical infiltrant alloy has a composition (weight percent) of copper(53%)-nickel(15%)-manganese(24%)-zinc(8%) and a melting point equal to about 1150 degrees Centigrade.
In certain embodiments, the cemented carbide members, which for example take on a drop-like shape, typically cover between about 40 percent to about 60 percent of the surface area of the hard composite. The cemented carbide members generally comprise about 90 weight percent of the hard composite 52. In the case where the cemented carbide members take on a square or rectangular shape, the members can cover up to between about 80 percent and about 85 percent of the surface area of the hard composite.
Another composition for the hard constituent-matrix composite material comprises hard constituents that comprise one or more sintered carbides wherein these carbides include tungsten, titanium, niobium, tantalum, hafnium, chromium and zirconium. The matrix powder typically comprises one or more sintered carbides, crushed sintered carbides, cast carbide, crushed carbides, tungsten carbide powders and chromium carbide powders. The infiltrant alloy has a composition (weight percent) of copper(53%)-nickel(15%)-manganese(24%)-zinc(8%) and a melting point equal to about 1150 degrees Centigrade.
In still another composition, the hard constituents that comprise crushed cemented tungsten carbide having a particle size equal to −80+120 mesh. The cemented carbide is cobalt cemented tungsten carbide where the cobalt is present in an amount of 10 weight percent. The hard composite further contains a matrix powder that could be any one of the matrix powders set forth in Table 2 through Table 6 hereof, but preferred a matrix powder may be any one of Matrix Powders Nos. 1 through 3 set forth in Table 2 a hereof. The ratio by weight of the matrix powder to the infiltrant alloy is about 40:60 by weight. In some applications, the hard constituent crushed cemented tungsten carbide particles (−80+120 mesh) range between about 2.5 volume percent and about 40 volume percent of the hard composite with the balance comprising matrix powder and infiltrant alloy. However, there are some applications in which the crushed cemented tungsten carbide particles range between about 2 volume percent to about 4 volume percent of the hard composite. There are also other applications in which the crushed cemented tungsten carbide particles range between about 30 volume percent and about 40 volume percent of the hard composite.
In yet another embodiment, the hard constituents may comprise one or more sintered carbides wherein these carbides include tungsten, titanium, niobium, tantalum, hafnium, chromium and zirconium. The matrix powder typically comprises one or more sintered carbides, crushed sintered carbides, cast carbide, crushed carbides, tungsten carbide powders and chromium carbide powders. The infiltrant alloy has a composition of copper(53%)-nickel(15%)-manganese(24%)-zinc(8%) and a melting point equal to about 1150 degrees Centigrade.
The hard constituent-matrix composite material can comprise crushed cemented tungsten carbide having a particle size equal to −80+120 mesh. The cemented carbide is cobalt cemented tungsten carbide where the cobalt is present in an amount of 10 weight percent. The hard composite further contains a matrix powder that could be any one of the matrix powders set forth in Table 2 through Table 6 hereof, but preferred a matrix powder may be any one of Matrix Powders Nos. 1 through 3 set forth in Table 2 hereof. The ratio by weight of the matrix powder to the infiltrant alloy is about 40:60 by weight. In some applications, the hard constituent crushed cemented tungsten carbide particles (−80+120 mesh) range between about 2.5 volume percent and about 40 volume percent of the hard composite with the balance comprising matrix powder and infiltrant alloy. However, there are some applications in which the crushed cemented tungsten carbide particles range between about 2 volume percent to about 4 volume percent of the hard composite. There are also other applications in which the crushed cemented tungsten carbide particles range between about 30 volume percent and about 40 volume percent of the hard composite.
In some embodiments, the hard constituents can also comprise cemented carbides, silicon carbides, boron carbide, aluminum oxide, zirconia and other suitable hard materials. The matrix powder typically comprises one or more of crushed tungsten carbide, crushed cemented tungsten carbide, crushed cast tungsten carbide, iron powder, tungsten carbide powder (the tungsten carbide made by a thermit process or from co-carburized tungsten carbide), chromium carbide powder, spherical cast carbide powder and/or spherical sintered carbide powders. The infiltrant alloy has a composition of copper(53%)-nickel(15%)-manganese(24%)-zinc(8%) and a melting point equal to about 1150 degrees Centigrade.
Examples of specific matrix powders (Mixtures Nos. 1 through 20) are set forth in Tables 2 through 6 hereinafter. In reference to the composition of the matrix powders, it should be appreciated that the crushed tungsten carbide component or the crushed cast tungsten carbide component may be substituted, in whole or in part, by spherical sintered tungsten carbide and/or spherical cast tungsten carbide particles. In some cases the spherical sintered tungsten carbide and/or spherical cast carbide particles (or powders) could be used 100% in combination or alone as the hard constituents in the matrix powders.
Additional examples of the hard constituent-matrix composite material are set forth hereinafter. One such example of the hard constituent-matrix composite material comprises sintered cobalt (10 weight percent cobalt) cemented tungsten carbide members and the matrix powder comprised Mixture No. 1 in Table 1 and the infiltrant alloy comprised (in weight percent) a Cu(53%)-Ni(15%)-Zn(8%)-Mn(24%) alloy described above. The matrix powder comprised 40 weight percent and the infiltrant alloy comprised 60 weight percent of the combination of the matrix powder and the infiltrant alloy. Depending upon the specific application, the cemented tungsten carbide members were present in a specified amount between about 1 weight percent and about 95 weight percent with the balance of the hard composite comprising the matrix powder and the infiltrant alloy. In the alternative and depending upon the specific application, the cemented tungsten carbide members were present in a specified amount between about 1 weight percent and about 90 percent of the surface area of the hard composite. For some applications, the cemented tungsten carbide members may be present in a range between about 1 percent to about 5 percent of the surface area. For other applications, the cemented tungsten carbide members may be present in a range between about 70 percent and about 90 percent of the surface area.
For yet another example of the hard constituent-matrix composite material, it comprised a sintered cobalt (6 weight percent cobalt) cemented tungsten carbide member. The matrix powder comprised Mixture No. 2. The infiltrant alloy comprised in weight percent) a Cu(53%)-Ni(15%)-Zn(8%)-Mn(24%). The matrix powder comprised 45 weight percent and the infiltrant alloy comprised 55 weight percent of the combination of the matrix powder and the infiltrant alloy. Depending upon the specific application, the cemented tungsten carbide members were present in a specified amount between about 1 weight percent and about 95 weight percent with the balance of the hard composite comprising the matrix powder and the infiltrant alloy. In the alternative and depending upon the specific application, the cemented tungsten carbide members were present in a specified amount between about 1 weight percent and about 90 percent of the surface area of the hard composite. For some applications, the cemented tungsten carbide members may be present in a range between about 1 percent to about 5 percent of the surface area. For other applications, the cemented tungsten carbide members may be present in a range between about 70 percent and about 90 percent of the surface area.
Still another example of the hard constituent-matrix composite material is a composition that comprises sintered cobalt (6 weight percent cobalt) cemented tungsten carbide cylindrical members. The matrix powder was Mixture No. 3 as set forth in Table 1. The infiltrant alloy comprised (in weight percent) a Cu(53%)-Ni(15%)-Zn(8%)-Mn(24%). The matrix powder comprised 40 weight percent and the infiltrant alloy comprised 60 weight percent of the combination of the matrix powder and the infiltrant alloy. Depending upon the specific application, the cemented tungsten carbide members were present in a specified amount between about 1 weight percent and about 95 weight percent with the balance of the hard composite comprising the matrix powder and the infiltrant alloy. In the alternative and depending upon the specific application, the cemented tungsten carbide members were present in a specified amount between about 1 weight percent and about 90 percent of the surface area of the hard composite. For some applications, the cemented tungsten carbide s may be present in a range between about 1 percent to about 5 percent of the surface area. For other applications, the cemented tungsten carbide members may be present in a range between about 70 percent and about 90 percent of the surface area.
Another example of the hard constituent-matrix composite material comprises nickel-coated sintered cobalt (10 weight percent cobalt) cemented tungsten carbide members. The matrix powder comprised Mixture No. 4 from Table 1. The infiltrant alloy comprised (in weight percent) a Cu(53%)-Ni(15%)-Zn(8%)-Mn(24%). The matrix powder comprised 45 weight percent and the infiltrant alloy comprised 55 weight percent of the combination of the matrix powder and the infiltrant alloy. Depending upon the specific application, the cemented tungsten carbide members were present in a specified amount between about 1 weight percent and about 95 weight percent with the balance of the hard composite comprising the matrix powder and the infiltrant alloy. In the alternative and depending upon the specific application, the cemented tungsten carbide members were present in a specified amount between about 1 weight percent and about 90 percent of the surface area of the hard composite. For some applications, the cemented tungsten carbide members may be present in a range between about 1 percent to about 5 percent of the surface area. For other applications, the cemented tungsten carbide members may be present in a range between about 70 percent and about 90 percent of the surface area.
It should be appreciated that the composition and microstructure of the hard composite material can impact the properties useful to the performance of the blade in a drilling or cutting application. Like for the cemented carbides and the steels, the hardness, toughness, erosion resistance and abrasion resistance are properties of the steel that impact upon the performance of the blade during use. As can also be appreciated, there are many variations for the composition and microstructure of the hard composite material so that the portions of the blades made from the hard composite material can exhibit a wide variety of properties to accommodate a wide variety of drilling or cutting applications.
In regard to the method of making the blades with multiple portions, as one alternative, the portions may be first made via a powder metallurgical technique such as, for example, sintering to form fully dense sintered portions, Then, these portions may be joined together via a suitable technique such as, for example, brazing to form the blade member.
As another alternative, there is provided a mold of the geometry of the blade. Powders of the various portions are positioned within the mold in pre-elected positions. The powder composite is then consolidated under heat and optionally pressure to form the blade. As one option in this alternative, one or more of the portions could be a fully dense portion and one or more of the portions could be in powder form. In the case where one of the portions is the hard constituent-matrix composite material, the hard constituents and matrix could be infiltrated with the infiltrant as described in U.S. Pat. No. 6,984,454 to Majagi.
In
As another alternative to the above method, the blades or least some portion(s) of the blades may not be essentially fully dense, but can be in powder form. In such a case, the powder(s) for the blade portion(s) are positioned in the mold and the various powders and any other components are also positioned within the mold. The contents of the mold are heated so as to consolidate all of the powder components (including any of the portions of the blades) whereby the blades are metallurgically joined to the cutter bit body.
A further embodiment of the invention is a method of producing an earth-boring bit, comprising casting the earth-boring bit from a molten mixture of at least one of iron, nickel, and cobalt and a carbide of a transition metal. The mixture may be a eutectic or near eutectic mixture. In these embodiments, the blades are positioned in the mold and the earth-boring bit may be cast directly to metallurgically bond the blade to the cutter bit body.
As can be appreciated, the present invention provides an improved blade, which carries cutter elements, that is affixed or attached to a tool or bit body. The tool or bit (e.g., fixed cutter bit) is useful in applications that involve impingement of the earth strata (e.g., downhole drilling, mining applications, road planning applications, concrete cutting applications, and the like). The improved blade increases the overall tool life of the tool or bit by the use of materials with improved combinations of strength, toughness, abrasion wear resistance and/or erosion wear resistance.
More specifically, tools or bits used in drilling boreholes in subterranean formations experience (or can experience) a significant amount of abrasive wear during the drilling operation due to the abrasive nature of a typical earth formation. Tools or bits used in other applications that impinge the earth strata (e.g., mining applications, road planning applications, concrete cutting applications, and the like) also experience a significant amount of abrasive wear during use. It is now apparent that the present invention provides an improved blade, which carries cutter elements, affixed or attached to a tool or bit body wherein the blade as well as the tool or bit exhibit improved abrasive wear resistance.
More specifically, tools or bits used in drilling boreholes in subterranean formations experience (or can experience) a significant amount of impact during the drilling operation due to the abrasive nature of a typical earth formation. Tools or bits used in other applications that impinge the earth strata (e.g., mining applications, road planning applications, concrete cutting applications, and the like) also experience a significant amount of impact during use. It is now apparent that the present invention provides an improved blade, which carries cutter elements, affixed or attached to a tool or bit body wherein the blade as well as the tool or bit exhibit improved impact resistance.
More specifically, tools or bits used in drilling boreholes in subterranean formations experience (or can experience) a significant amount of erosive wear during the drilling operation due to the abrasive nature of a typical earth formation. Such erosive wear can be exacerbated by fluid emitted from the nozzles in the bit body that directly impinges upon the tool or bit body, as well as the blades that carry the cutter elements. Tools or bits used in other applications that impinge the earth strata (e.g., mining applications, road planning applications, concrete cutting applications, and the like) also experience a significant amount of erosive wear during use. It is now apparent that the present invention provides an improved blade, which carries cutter elements, affixed or attached to a tool or bit body wherein the blade as well as the tool or bit exhibit improved erosive wear resistance.
All patents, patent applications, articles and other documents identified herein are hereby incorporated by reference herein. Other embodiments of the invention may be apparent to those skilled in the art from a consideration of the specification or the practice of the invention disclosed herein. It is intended that the specification and any examples set forth herein be considered as illustrative only, with the true spirit and scope of the invention being indicated by the following claims.
