GB2228031A - Improvements in or relating to cutting elements for rotary drill bits - Google Patents
Improvements in or relating to cutting elements for rotary drill bits Download PDFInfo
- Publication number
- GB2228031A GB2228031A GB9003141A GB9003141A GB2228031A GB 2228031 A GB2228031 A GB 2228031A GB 9003141 A GB9003141 A GB 9003141A GB 9003141 A GB9003141 A GB 9003141A GB 2228031 A GB2228031 A GB 2228031A
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- United Kingdom
- Prior art keywords
- cutting element
- substrate
- metal
- tungsten
- element according
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Links
- 238000005520 cutting process Methods 0.000 title claims abstract description 56
- 239000000758 substrate Substances 0.000 claims abstract description 52
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 claims abstract description 44
- 229910052751 metal Inorganic materials 0.000 claims abstract description 42
- 239000002184 metal Substances 0.000 claims abstract description 42
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims abstract description 39
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 39
- 239000010937 tungsten Substances 0.000 claims abstract description 39
- 239000000463 material Substances 0.000 claims abstract description 33
- 229910003460 diamond Inorganic materials 0.000 claims abstract description 23
- 239000010432 diamond Substances 0.000 claims abstract description 23
- 239000011819 refractory material Substances 0.000 claims abstract description 16
- 239000011156 metal matrix composite Substances 0.000 claims abstract description 13
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 9
- 239000011230 binding agent Substances 0.000 claims abstract description 8
- 239000002923 metal particle Substances 0.000 claims abstract description 6
- 229910052802 copper Inorganic materials 0.000 claims abstract description 5
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 5
- 229910052742 iron Inorganic materials 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 15
- 239000002245 particle Substances 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 7
- 239000003054 catalyst Substances 0.000 claims description 6
- 239000002131 composite material Substances 0.000 claims description 6
- 238000007731 hot pressing Methods 0.000 claims description 5
- 238000005245 sintering Methods 0.000 claims description 5
- 150000001875 compounds Chemical class 0.000 claims description 4
- 238000001816 cooling Methods 0.000 claims description 4
- 239000007787 solid Substances 0.000 claims description 4
- 229910017052 cobalt Inorganic materials 0.000 claims description 3
- 239000010941 cobalt Substances 0.000 claims description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical group [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 3
- 238000005552 hardfacing Methods 0.000 claims description 2
- 230000008595 infiltration Effects 0.000 claims description 2
- 238000001764 infiltration Methods 0.000 claims description 2
- 238000005299 abrasion Methods 0.000 description 10
- 230000015572 biosynthetic process Effects 0.000 description 9
- 238000005755 formation reaction Methods 0.000 description 9
- 238000005553 drilling Methods 0.000 description 8
- 238000000429 assembly Methods 0.000 description 5
- 230000000712 assembly Effects 0.000 description 5
- 230000003628 erosive effect Effects 0.000 description 4
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 238000005219 brazing Methods 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 229910052735 hafnium Inorganic materials 0.000 description 2
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 description 2
- 229910052741 iridium Inorganic materials 0.000 description 2
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- 229910052758 niobium Inorganic materials 0.000 description 2
- 239000010955 niobium Substances 0.000 description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 2
- 229910052762 osmium Inorganic materials 0.000 description 2
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 description 2
- 229910052702 rhenium Inorganic materials 0.000 description 2
- WUAPFZMCVAUBPE-UHFFFAOYSA-N rhenium atom Chemical compound [Re] WUAPFZMCVAUBPE-UHFFFAOYSA-N 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- 239000010948 rhodium Substances 0.000 description 2
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 2
- 229910052715 tantalum Inorganic materials 0.000 description 2
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- 241001568665 Ocinebrellus inornatus Species 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000012876 carrier material Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B10/00—Drill bits
- E21B10/46—Drill bits characterised by wear resisting parts, e.g. diamond inserts
- E21B10/56—Button-type inserts
- E21B10/567—Button-type inserts with preformed cutting elements mounted on a distinct support, e.g. polycrystalline inserts
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/64—Burning or sintering processes
- C04B35/645—Pressure sintering
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B37/00—Joining burned ceramic articles with other burned ceramic articles or other articles by heating
- C04B37/001—Joining burned ceramic articles with other burned ceramic articles or other articles by heating directly with other burned ceramic articles
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B37/00—Joining burned ceramic articles with other burned ceramic articles or other articles by heating
- C04B37/02—Joining burned ceramic articles with other burned ceramic articles or other articles by heating with metallic articles
- C04B37/021—Joining burned ceramic articles with other burned ceramic articles or other articles by heating with metallic articles in a direct manner, e.g. direct copper bonding [DCB]
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
- C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
- C04B2237/32—Ceramic
- C04B2237/36—Non-oxidic
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
- C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
- C04B2237/32—Ceramic
- C04B2237/36—Non-oxidic
- C04B2237/363—Carbon
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
- C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
- C04B2237/40—Metallic
- C04B2237/401—Cermets
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
- C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
- C04B2237/40—Metallic
- C04B2237/403—Refractory metals
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
- C04B2237/50—Processing aspects relating to ceramic laminates or to the joining of ceramic articles with other articles by heating
- C04B2237/76—Forming laminates or joined articles comprising at least one member in the form other than a sheet or disc, e.g. two tubes or a tube and a sheet or disc
Abstract
A cutting element 12 for a rotary drill bit comprises a thin superhard table 13 of polycrystalline diamond material, defining a front cutting face, bonded to a less hard substrate 14. The substrate 14 is formed from a material containing at least a proportion of tungsten metal. The substrate 14 may be formed of a metal matrix composite comprising tungsten metal particles in a metal binder phase comprising material selected from: Cu, Co, Ni + Cu, Ni + Fe, Ni + Fe + Mo, Co + Ni. The substrate may also include tungsten carbide in which case the tungsten metal may be replaced by another softer refractory material. <IMAGE>
Description
"Improvements in or relating to cutting elements for rotary drill bitsOf
The invention relates to rotary drill bits for use in drilling or coring holes in subsurface formations and, in particular, to cutting elements for use on such bits, and methods of manufacturing such cutting elements.
Rotary drill bits of the kind to which the invention relates comprise a bit body having a shank and a passage for supplying drilling fluid to the face of the bit. The bit body carries a plurality of so called "preform" cutting elements. Each cutting element comprises a thin facing table of superhard material, which defines the front cutting face of the element, bonded to a less hard substrate.
Normally the superhard table is formed of polycrystalline diamond material and the substrate is formed of cemented tungsten carbide. The preform cutting elements are usually mounted on the bit body by being bonded, for example by brazing, to a carrier which may be in the form of a stud of tungsten carbide which is received and located in a socket in the bit body.
Tungsten carbide has certain characteristics which render it particularly suitable for use in the substrate and carrier of such a cutter assembly. Thus, it exhibits high rigidity, high resistance to the erosion to which such cutter assemblies are subject in use, and hot strength. Also. the coefficient of 41.
expansion of tungsten carbide is sufficiently close to the coefficient of expansion of polycrystalline diamond to reduce the residual stresses which can occur when the two materials are bonded together. However, some of the other characteristics of cemented tungsten carbide have certain disadvantages. For example, cemented tungsten carbide has low toughness (i.e. it is comparatively brittle) and this can lead to failure of such cutter assemblies in use, as a result of impact f orces on the assembly.
Also, when a preformed cutting element of the kind referred to is mounted on a. drill bit, it is mounted with its front face facing in the direction of movement, its rear face trailing behind and part of the peripheral surface of the cutting element, between the front and rear surfaces, rubbing on the formation being drilled. As drilling proceeds this intermediate surface wears down to form a wear-flat.
Due to its two-layer construction, the cutting element is self-sharpening since the part of the less hard substrate which rubs on the formation wears away more quickly than the part-of.the diamond table rubbing on the formation. Since the rearward substrate wears away more quickly,, it does not bear on the formation being cut to the same extent or with the same pressure as the diamond table. The compact is therefore rendered self-sharpening by this constant greater wearing away of material rearwardly of the front cutting 0 face.
However. the abrasion resistance of the wearf lat rubbing on the formation generates heat which is additional to the heat generated by cutting. Tungsten carbide has high abrasion resistance, and when the substrate is formed from tungsten carbide the additional heat generated by abrasion nay be suf f icient to cause the thermally activated deterioration of the diamond table at an increasingly rapid rate. It is generally accepted that a standard cutting element of the kind described, having a tungsten carbide substrate, generally operates efficiently only until it is about 30% worn. From thereon the cutting element may become thermally unstable and wear extremely rapidly leading quickly to failure of the cutter. When a suf f icient number of cutting elements have failed in this manner the bit becomes useless for further drilling.
The combination of low toughness and high heat generation can also cause heat checking of the tungsten carbide carrier material with resultant premature failure of the bit. "Heat checking" is a term in the art which refers to craze cracking of the wear flat which develops on the carrier, due to abrasive heating with intermittent quenching by the drilling fluid.
The approach taken by the present invention is to overcome the abovementioned problems by reducing the abrasion resistance of the less hard substrate of the cutting element so as to reduce the additional heat generated by rubbing of the wear-f lat on the formation being drilled. It is, however, desirable that abrasion resistance of the substrate should be reduced without also reducing its 5 cuttina elements erosion resistance. In use the are subjected to the substantial eroding ef fect of abrasive drilling f luid f lowing over the cutting elements continuously during drilling. Existing cutting elements having a cemented tungsten carbide substrate have considerable resistance to such erosion and this should preferably not be significantly reduced in attempting to reduce the abrasion resistance.
According to one aspect of the invention there is provided a cutting element for a rotary drill bit comprising a thin superhard table of polycrystalline diamond material. defining a front cutting face, bonded to a less hard substrate. wherein the substrate is formed from a material containing at least a proportion of tungsten metal.
Use of a substrate containing tungsten metal may overcome the problems described above with relation to the existing cemented tungsten carbide material. The presence of the tungsten metal in the substrate has the effect of reducing the abrasion resistance of the substrate, and thereby reducing the heat generated by rubbing of the wear flat of the substrate on the formation being drilled.
In addition, the tungsten-containing material may be even stronger than cemented tungsten carbide in cantilever bending and shear forces to which cutter assemblies may be subject in use.
The material of the substrate preferably contains at least about 50% (by weight) tungsten metal, for example at least about 80%. In a preferred embodiment the substrate is formed of a metal matrix composite comprising tungsten metal particles in a metal binder phase.
The metal matrix composite nay be formed by a sintering process, or by hot-pressing.
Any suitable metal or metal alloy may be used as the metal binder phase of the composite. For example, any of the following materials may be suitable: Cu, Co, Ni + Cu, Ni + Fe. Ni + Fe + Mo, Co + Ni.
is In one embodiment according to the invention the metal matrix composite has the following composition (percentages by weight):
W 95% Ni 3.5% Fe 1.5% The invention includes within its scope arrangements where the substrate is formed of a metal matrix including tungsten metal in addition to the tungsten carbide normally used. In such embodiments of the invention the tungsten metal and tungsten carbide together may constitute at least about 50% by weight of the material from which the carrier is formed, and preferably at least about 80%.
The metal matrix composite may include tungsten metal particles and tungsten carbide particles in a metal binder phase and nay be formed by sintering, by an infiltration process or by hot pressing a mixture of powdered tungsten carbide and tungsten metal with a catalyst, such as cobalt.
In the case where the substrate includes tungsten carbide. the tungsten metal may be replaced by another refractory material which is softer than the tungsten carbide. Such refractory materials include boron, hafnium, iridium, molybdenum, niobium, osmium, rhenium, rhodium, tantalum and zirconium. Accordingly the invention further provides a cutting element for a rotary drill bit comprising a thin hard facing table of polycrystalline diamond material, defining a front cutting face, bonded to a less hard substrate, wherein the substrate comprises a compound of cemented tungsten carbide and a softer refractory material.
The invention also provides a method of forming a cutting element for a rotary drill bit comprising placing in a high -pressure/high temperature press a layer of polycrystalline diamond particles, said layer having a front face and a rear face, and, in contact with said rear face, a further layer including at least a proportion of tungsten metal, and subjecting said layers to high pressure and temperature so as to form, on cooling, a solid composite compact comprising a superhard table of polycrystalline diamond material bonded to a less hard substrate containing at least a proportion of tungsten metal.
The invention further provides a method of forming a cutting element for a rotary drill bit comprising placing in a high pressure/high temperature press a layer of polycrystalline diamond particles, said layer having a front face and a rear face, and, in contact with said rear face, a further layer comprising a mixture including powdered tungsten carbide, a powdered softer refractory material and a catalyst, and subjecting said layers to high pressure and temperature so as to form, on cooling, a solid composite compact comprising a superhard table of polycrystalline diamond material bonded to a less hard substrate comprising a compound including cemented tungsten carbide and said softer refractory material.
The invention includes within its scope a cutter assembly for a rotary drill bit comprising a cutting element according to the invention mounted, for example by brazing, on a carrier which may be in the form of a stud or post to be received in a socket in the bit body.
The invention also includes within its scope a rotary drill bit of the kind first referred to including cutting elements or cutter assemblies according to the invention.
The following is a more detailed description -B- of an embodiment of the invention, reference being made to the accompanying drawing which is a side elevation of a typical cutter assembly to-which the present invention may be applied.
The cutter assembly comprises a generally cylindrical stud 10, which is formed adjacent one end thereof with an inclined plane surface 11 which is disposed at an angle to the longitudinal axis of the stud 10. The stud 10 may be formed from cemented tungsten carbide, but is preferably formed from a material containing at least a proportion of tungsten metal in accordance with British Patent Specification No. 2216577.
Mounted on the inclined surface 11 of the stud is a preform cutting element 12 comprising a superhard facing table 13 of polycrystalline diamond bonded to a thicker and less hard substrate 14. The cutting element 12 is in the form of a circular disc.
The rear surface 15 of the cutting element is flat and is brazed to the inclined plane surface 11 of the stud 10. The cutting element may be brazed to the stud by the process known as IlLS bonding" in which a heat sink is applied to the polycrystalline diamond table of the cutting element to prevent thermal degradation of the table during the bonding process.
A plurality of such cutter assemblies are mounted in the body of a rotary drill bit of the kind first referred to. The bit body is formed over the surface thereof with a plurality of cylindrical sockets of circular crosssection and received in each socket is the stud 10 of a cutter assembly. The cutter assembly is usually shrink-fitted or brazed into its socket. The general construction of such drill bits is well known and will not therefore be described in further detail.
Hitherto. prior art two-layer cutting elements of the kind shown in the drawing have comprised a substrate 14 of cemented tungsten carbide. The front diamond table 13 and the substrate 14 are formed simultaneously by placing layers of polycrystalline diamond particles and tungsten carbide in a high pressure/high temperature press,, a catalyst, such as cobalt, normally also being present in the layer of tungsten carbide.
According to the present invention, the material to form the substrate includes at least a proportion of tungsten metal, or comprises tungsten carbide and tungsten metal or some other softer refractory material.
In one embodiment of the invention the substrate 14 is a metal matrix composite having the following composition (percentages by weight):
W 95% Ni 3.5% Fe 1.5% In this example the percentage of tungsten metal is greater than 80%,, but lower percentages of tungsten metal may also provide advantage. Preferably, however, the inaterial contains at least about 50% tungsten metal.
Lower percentages of tungsten metal may be appropriate in the case where the material of the substrate also includes tungsten carbide, such as a metal matrix composite including tungsten metal particles and tungsten carbide particles in a metal binder phase.
In the case where the substrate includes tungsten carbide, the tungsten metal may be replaced by another refractory material which is softer than the tungsten carbide. Such refractory materials include boron, hafnium, iridium, molybdenum, niobium, osmium, rhenium, rhodium, tantalum and zirconium.
Where the material includes tungsten carbide, the tungsten metal (or other softer refractory material) and tungsten carbide together preferably constitute at least about 50% by weight. and more preferably 80%, of the material from which the carrier is formed. The substrate may be formed by sintering or hot-pressing. Such methods are well known in the art and will not therefore be described in detail.
As previously explained, the presence of the tungsten metal or other softer refractory material in the substrate 14 serves to reduce the abrasion resistance of the substrate. The reduction in abrasion resistance results in less generation of heat when the p cutting element bears against the formation being drilled, and thus delays the onset of thermal degradation of the diamond table.
As previously mentioned, although the stud 10 may be formed from cemented tungsten carbide, it might also be formed from similar material to the substrate 14, and may comprise, for example, tungsten carbide including a softer refractory material such as tungsten metal, as described in our British Patent Application No. 2216577. This may be advantageous, since after a certain degree of wear has occurred the wear-flat will also extend across part of the end of the stud 10, and reduction of the abrasion resistance of the stud will in that case assist in reducing the heat generated during drilling.
Claims (20)
1. A cutting element for a rotary drill bit comprising a thin superhard table of polycrystalline diamond material, defining a front cutting face, bonded 5 to a less hard substrate. wherein the substrate is formed from a material containing at least a proportion of tungsten metal.
2. A cutting element according to Claim 1, wherein the material of the substrate contains at least about 50% (by weight) tungsten metal.
3. A cutting element according to Claim 1, wherein the material of the substrate contains at least about 80% (by weight) tungsten metal.
4. A cutting element according to any of Claims 1 15 to 3, wherein the substrate is formed of a metal matrix composite comprising tungsten metal particles in a metal binder phase.
5. A cutting element according to Claim 4, wherein the metal matrix composite is formed by a sintering process.
6. A cutting element according to Claim 4.
wherein the metal matrix composite is formed by hotpressing.
7. A cutting element according to any of Claims 4 25 to 6, wherein the metal binder phase of the composite comprises a material selected from:
Cu, Co, Ni + Cu. Ni + Fe, Ni + Fe + Mo, Co + Ni.
8. A cutting element according to Claim 7, o' wherein the metal matrix composite has the following composition (percentages by weight):
W 95%.
Ni 3.5% PE 1.5%
9. A cutting element according to any of Claims 1 to 8, wherein the substrate further includes tungsten carbide.
10. A cutting element according to Claim 9, wherein the tungsten metal and tungsten carbide together constitute at least about 50% by weight of a material from which the substrate is formed.
11. A cutting element according to Claim 9, wherein the tungsten metal and tungsten carbide together constitute at least about 80% by weight of the material from which the substrate is formed.
12. A cutting element according to any of Claims 9 to 11, wherein the substrate.is a metal matrix composite including tungsten metal particles and tungsten carbide particles in a metal binder phase.
13. A cutting element according to Claim 12, wherein the metal matrix composite is formed by sintering, by an infiltration process, or by hot pressing a mixture of powdered tungsten carbide and tungsten metal with a catalyst.
14. A cutting element for a rotary drill bit comprising a thin hard facing table of polycrystalline diamond material. defining a front cutting face, bonded to a less hard substrate, wherein the substrate comprises a compound of cemented tungsten carbide and a softer refractory material.
15. A method of forming a cutting element for a 5 rotary drill bit comprising placing in a high pressure/high temperature press a layer of polycrystalline diamond particles, said layer having a front face and -a rear face, and, in contact with said rear face, a further layer including at least a proportion of tungsten metal, and subjecting said layers to high pressure and temperature so as to form, on cooling, a solid composite compact comprising a superhard table of polycrystalline diamond material bonded to a less hard substrate containing at least a proportion of tungsten metal.
16. A method of forming a cutting element f or a rotary drill bit comprising placing in a high pressure/high temperature press a layer of polycrystalline diamond particles. said layer having a front face and a rear face, and, in contact with said rear face, a further layer comprising a mixture including powdered tungsten carbide, a powdered softer refractory material and a catalyst, and subjecting said layers to high pressure and temperature so as to form, on cooling, a solid composite compact comprising a superhard table of polycrystalline diamond material bonded to a less hard substrate comprising a compound including cemented tungsten carbide and said softer refractory material.
17. A method according to Claim 16, wherein the softer refractory material is tungsten metal.
18. A method according to Claim 16 or Claim 17, 5 wherein the catalyst is cobalt.
19. A cutter assembly for a rotary drill bit comprising a cutting element according to any of Claims 1 to 14 mounted on a carrier in the f orm of a stud or post to be received in a socket in the bit body.
20. A cutting element or cutter assembly f or a rotary drill bit substantially as hereinbefore described with reference to the accompanying drawing.
Published 1990 at The Patent Office, State House. 6671 I-Iighi-iolborn. London WC1R4TP. Further copies maybe obtainedfromThePatentOfnce. Sales Branch. St Mary Cray. Orpington. Kent BR5 3RD. Printed by MWtIplex techniques ltd, St MarY CraY. Kent. Con. 1W
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB898903246A GB8903246D0 (en) | 1989-02-14 | 1989-02-14 | Improvements in or relating to cutting elements for rotary drill bits |
| GB898925409A GB8925409D0 (en) | 1989-11-10 | 1989-11-10 | Improvements in or relating to cutting elements for rotary drill bits |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9003141D0 GB9003141D0 (en) | 1990-04-11 |
| GB2228031A true GB2228031A (en) | 1990-08-15 |
| GB2228031B GB2228031B (en) | 1993-09-22 |
Family
ID=26294947
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9003141A Expired - Fee Related GB2228031B (en) | 1989-02-14 | 1990-02-12 | Improvements in or relating to cutting elements for rotary drill bits |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0384623B1 (en) |
| DE (1) | DE69006867T2 (en) |
| GB (1) | GB2228031B (en) |
| IE (1) | IE64021B1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0592210A2 (en) * | 1992-10-07 | 1994-04-13 | Camco Drilling Group Limited | Cutting element for rotary drag drillbit |
| US5469927A (en) * | 1992-12-10 | 1995-11-28 | Camco International Inc. | Cutting elements for rotary drill bits |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5460233A (en) * | 1993-03-30 | 1995-10-24 | Baker Hughes Incorporated | Diamond cutting structure for drilling hard subterranean formations |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2151283A (en) * | 1983-12-03 | 1985-07-17 | Nl Petroleum Prod | Improvements in rotary drill bits |
| GB2152104A (en) * | 1983-12-03 | 1985-07-31 | Nl Petroleum Prod | Rotary drill bits and cutting elements for such bits |
| GB2216577A (en) * | 1988-03-11 | 1989-10-11 | Reed Tool Co | Improvements in or relating to cutter assemblies for rotary drill bits |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3982911A (en) * | 1972-11-01 | 1976-09-28 | General Electric Company | Process for the preparation of a composite cubic boron nitride layer abrasive body |
| US4319707A (en) * | 1978-01-10 | 1982-03-16 | General Electric Company | Brazing apparatus to manufacture composite compact components |
| US4225322A (en) * | 1978-01-10 | 1980-09-30 | General Electric Company | Composite compact components fabricated with high temperature brazing filler metal and method for making same |
| DE3226648C2 (en) * | 1982-07-16 | 1984-12-06 | Dornier System Gmbh, 7990 Friedrichshafen | Heterogeneous tungsten alloy powder |
| US4626281A (en) * | 1983-07-26 | 1986-12-02 | The United States Of America As Represented By The United States Department Of Energy | Hard metal composition |
| US4979234A (en) * | 1988-12-20 | 1990-12-18 | At&T Bell Laboratories | Saturated semiconductor laser amplifier for compensation of optical fibre dispersion |
-
1990
- 1990-02-12 GB GB9003141A patent/GB2228031B/en not_active Expired - Fee Related
- 1990-02-12 DE DE69006867T patent/DE69006867T2/en not_active Expired - Fee Related
- 1990-02-12 EP EP90301437A patent/EP0384623B1/en not_active Expired - Lifetime
- 1990-02-14 IE IE52290A patent/IE64021B1/en not_active IP Right Cessation
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2151283A (en) * | 1983-12-03 | 1985-07-17 | Nl Petroleum Prod | Improvements in rotary drill bits |
| GB2152104A (en) * | 1983-12-03 | 1985-07-31 | Nl Petroleum Prod | Rotary drill bits and cutting elements for such bits |
| GB2216577A (en) * | 1988-03-11 | 1989-10-11 | Reed Tool Co | Improvements in or relating to cutter assemblies for rotary drill bits |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0592210A2 (en) * | 1992-10-07 | 1994-04-13 | Camco Drilling Group Limited | Cutting element for rotary drag drillbit |
| EP0592210A3 (en) * | 1992-10-07 | 1995-03-15 | Camco Drilling Group Ltd | Cutting element for rotary drag drillbit. |
| US5469927A (en) * | 1992-12-10 | 1995-11-28 | Camco International Inc. | Cutting elements for rotary drill bits |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0384623A1 (en) | 1990-08-29 |
| IE900522L (en) | 1990-08-14 |
| IE64021B1 (en) | 1995-06-28 |
| GB2228031B (en) | 1993-09-22 |
| DE69006867D1 (en) | 1994-04-07 |
| DE69006867T2 (en) | 1994-10-13 |
| GB9003141D0 (en) | 1990-04-11 |
| EP0384623B1 (en) | 1994-03-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20060212 |