CA1231938A - Rock bit cutter cones having metallurgically bonded cutter inserts - Google Patents
Rock bit cutter cones having metallurgically bonded cutter insertsInfo
- Publication number
- CA1231938A CA1231938A CA000466146A CA466146A CA1231938A CA 1231938 A CA1231938 A CA 1231938A CA 000466146 A CA000466146 A CA 000466146A CA 466146 A CA466146 A CA 466146A CA 1231938 A CA1231938 A CA 1231938A
- Authority
- CA
- Canada
- Prior art keywords
- cutter
- core
- alloys
- cladding
- percent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000011435 rock Substances 0.000 title claims abstract description 45
- 238000005253 cladding Methods 0.000 claims abstract description 89
- 238000000034 method Methods 0.000 claims abstract description 73
- 230000008569 process Effects 0.000 claims abstract description 66
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 52
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 40
- 229910052751 metal Inorganic materials 0.000 claims abstract description 28
- 239000002184 metal Substances 0.000 claims abstract description 28
- 238000004663 powder metallurgy Methods 0.000 claims abstract description 27
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 25
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 25
- 238000000576 coating method Methods 0.000 claims abstract description 14
- 239000011248 coating agent Substances 0.000 claims abstract description 13
- 239000000843 powder Substances 0.000 claims description 61
- 239000000203 mixture Substances 0.000 claims description 33
- 239000000463 material Substances 0.000 claims description 32
- 229910000831 Steel Inorganic materials 0.000 claims description 30
- 239000010959 steel Substances 0.000 claims description 30
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 claims description 28
- 229910017052 cobalt Inorganic materials 0.000 claims description 27
- 239000010941 cobalt Substances 0.000 claims description 27
- 238000010438 heat treatment Methods 0.000 claims description 23
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 22
- 239000011195 cermet Substances 0.000 claims description 22
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 22
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 22
- 238000005553 drilling Methods 0.000 claims description 20
- 239000007787 solid Substances 0.000 claims description 20
- 238000009792 diffusion process Methods 0.000 claims description 19
- 229910000990 Ni alloy Inorganic materials 0.000 claims description 18
- 238000000151 deposition Methods 0.000 claims description 18
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 17
- 229910002804 graphite Inorganic materials 0.000 claims description 15
- 239000010439 graphite Substances 0.000 claims description 15
- 238000001513 hot isostatic pressing Methods 0.000 claims description 15
- 238000003825 pressing Methods 0.000 claims description 15
- 229910001315 Tool steel Inorganic materials 0.000 claims description 13
- 229910001316 Ag alloy Inorganic materials 0.000 claims description 12
- 229910001020 Au alloy Inorganic materials 0.000 claims description 12
- 229910000531 Co alloy Inorganic materials 0.000 claims description 12
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 12
- 229910000881 Cu alloy Inorganic materials 0.000 claims description 12
- 229910001260 Pt alloy Inorganic materials 0.000 claims description 12
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 12
- 229910001362 Ta alloys Inorganic materials 0.000 claims description 12
- 229910052802 copper Inorganic materials 0.000 claims description 12
- 239000010949 copper Substances 0.000 claims description 12
- 239000003353 gold alloy Substances 0.000 claims description 12
- 229910052709 silver Inorganic materials 0.000 claims description 12
- 239000004332 silver Substances 0.000 claims description 12
- 229910001252 Pd alloy Inorganic materials 0.000 claims description 11
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 11
- 229910052737 gold Inorganic materials 0.000 claims description 11
- 239000010931 gold Substances 0.000 claims description 11
- 229910052763 palladium Inorganic materials 0.000 claims description 11
- 229910052697 platinum Inorganic materials 0.000 claims description 11
- 229910052715 tantalum Inorganic materials 0.000 claims description 11
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 11
- 230000015572 biosynthetic process Effects 0.000 claims description 9
- 238000005755 formation reaction Methods 0.000 claims description 9
- 229910052742 iron Inorganic materials 0.000 claims description 9
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 7
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 7
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 7
- 229910052804 chromium Inorganic materials 0.000 claims description 7
- 239000011651 chromium Substances 0.000 claims description 7
- 229910052750 molybdenum Inorganic materials 0.000 claims description 7
- 239000011733 molybdenum Substances 0.000 claims description 7
- 230000035939 shock Effects 0.000 claims description 7
- 229910052710 silicon Inorganic materials 0.000 claims description 7
- 239000010703 silicon Substances 0.000 claims description 7
- 229910052720 vanadium Inorganic materials 0.000 claims description 7
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 7
- 150000002739 metals Chemical class 0.000 claims description 6
- 229910001209 Low-carbon steel Inorganic materials 0.000 claims description 5
- 238000009713 electroplating Methods 0.000 claims description 4
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 4
- 229910052721 tungsten Inorganic materials 0.000 claims description 4
- 239000010937 tungsten Substances 0.000 claims description 4
- 239000005864 Sulphur Substances 0.000 claims description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims 6
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 claims 6
- 239000010936 titanium Substances 0.000 claims 6
- 229910052719 titanium Inorganic materials 0.000 claims 6
- 229910001021 Ferroalloy Inorganic materials 0.000 claims 4
- 229910052717 sulfur Inorganic materials 0.000 claims 4
- 239000011593 sulfur Substances 0.000 claims 4
- 230000015556 catabolic process Effects 0.000 abstract description 6
- 238000006731 degradation reaction Methods 0.000 abstract description 6
- 238000007796 conventional method Methods 0.000 abstract 1
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 238000003754 machining Methods 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 229910000906 Bronze Inorganic materials 0.000 description 2
- 241001505295 Eros Species 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical group [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 2
- 239000010974 bronze Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000000314 lubricant Substances 0.000 description 2
- 238000001000 micrograph Methods 0.000 description 2
- -1 palladiurn Substances 0.000 description 2
- 239000012255 powdered metal Substances 0.000 description 2
- 238000005496 tempering Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- FSVJFNAIGNNGKK-UHFFFAOYSA-N 2-[cyclohexyl(oxo)methyl]-3,6,7,11b-tetrahydro-1H-pyrazino[2,1-a]isoquinolin-4-one Chemical compound C1C(C2=CC=CC=C2CC2)N2C(=O)CN1C(=O)C1CCCCC1 FSVJFNAIGNNGKK-UHFFFAOYSA-N 0.000 description 1
- SUBDBMMJDZJVOS-UHFFFAOYSA-N 5-methoxy-2-{[(4-methoxy-3,5-dimethylpyridin-2-yl)methyl]sulfinyl}-1H-benzimidazole Chemical compound N=1C2=CC(OC)=CC=C2NC=1S(=O)CC1=NC=C(C)C(OC)=C1C SUBDBMMJDZJVOS-UHFFFAOYSA-N 0.000 description 1
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 241001181114 Neta Species 0.000 description 1
- 229910009043 WC-Co Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 238000009694 cold isostatic pressing Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical group [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000007772 electroless plating Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000005552 hardfacing Methods 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- UPIXZLGONUBZLK-UHFFFAOYSA-N platinum Chemical compound [Pt].[Pt] UPIXZLGONUBZLK-UHFFFAOYSA-N 0.000 description 1
- 239000012254 powdered material Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 230000003252 repetitive effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 230000036346 tooth eruption Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
- B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
- B22F7/062—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools involving the connection or repairing of preformed parts
- B22F7/064—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools involving the connection or repairing of preformed parts using an intermediate powder layer
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B10/00—Drill bits
- E21B10/08—Roller bits
- E21B10/22—Roller bits characterised by bearing, lubrication or sealing details
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK 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
- E21B10/50—Drill bits characterised by wear resisting parts, e.g. diamond inserts the bit being of roller type
- E21B10/52—Drill bits characterised by wear resisting parts, e.g. diamond inserts the bit being of roller type with chisel- or button-type inserts
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
- B22F2005/001—Cutting tools, earth boring or grinding tool other than table ware
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Geology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Mechanical Engineering (AREA)
- Fluid Mechanics (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Materials Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Composite Materials (AREA)
- Earth Drilling (AREA)
Abstract
ROCK BIT CUTTER CONES HAVING
METALLURGICALLY BONDED CUTTER INSERTS
ABSTRACT OF THE DISCLOSURE
A rock bit cutter cone for a drill bit is disclosed wherein hard carbide cutter inserts are metallurgically bonded into an interior core of the cone through a cladding. The cladding is bonded onto the exterior surface of the core by a powder metallurgy process. The cladding retains the inserts in the core. A thin layer or coating of a suitable metal, preferably nickel, is provided on the carbide insert prior to mounting into the core. The coating prevents degradation of the carbide through loss of carbon into the core during the powder metallurgy process and accomodates mismatch of thermal expansion between the cutter insert and the core. The interior of the cone is formed to provide bearing surfaces either by conventional techniques, or by powder metallurgy processes.
Bearing surfaces formed in the interior of the core by powder metallurgy processes may be hard so as to permit an open bearing structure for the drill bit.
METALLURGICALLY BONDED CUTTER INSERTS
ABSTRACT OF THE DISCLOSURE
A rock bit cutter cone for a drill bit is disclosed wherein hard carbide cutter inserts are metallurgically bonded into an interior core of the cone through a cladding. The cladding is bonded onto the exterior surface of the core by a powder metallurgy process. The cladding retains the inserts in the core. A thin layer or coating of a suitable metal, preferably nickel, is provided on the carbide insert prior to mounting into the core. The coating prevents degradation of the carbide through loss of carbon into the core during the powder metallurgy process and accomodates mismatch of thermal expansion between the cutter insert and the core. The interior of the cone is formed to provide bearing surfaces either by conventional techniques, or by powder metallurgy processes.
Bearing surfaces formed in the interior of the core by powder metallurgy processes may be hard so as to permit an open bearing structure for the drill bit.
Description
The present invention i5 directed to improvements in the construction of roc~ bits. More particularlyl the present invention is directed to cutter cones of rock bits having metallurgically bonded cutting inserts.
Rock bits used for drilling in subterranean fo~nations when prospecting for oil, gas or minerals, have a main body which is connected to a drill string, and a plurality, typically three, cutter cones rotatably mounted on journals. The journals extend at an angle from the main body of the rocX bit~
As the main body of the rock bit is rotated either from the surface through the drill string, or by a downhole motor, the cutter cones rotate on their resyective journals.
During their rotation, teeth provided in the cones come into contact with the subterranean formation, and provide the drill-ing action.
As is known, the subterranean environment is often very harsh. Highly abrasive drilling mud is continuously circulated from the surface to remove debris of the drilling, and for other purposes. Furthermore, the suhterranean for-mations are composed of rock with a wide range of compressive strength and abrasiveness.
Generally speaking, the prior art has provided two types of cutter cones to cope with the above-noted conditions and to perform the above-noted drilling operations. The first typc of drilling cone is known as "milled-tooth" cone becausc the cone has relatively sharp cutting teeth obtained by appro-priate rnilling of the cone hody. Milled tooth cones, generally ~ ,, J
33~
have a short life and are used ~or drilling in low compressive strength (soft) subterran~an formations.
A second type of cutter cone, used for drilling in higher compressive strength (harder) formations, has a plurality o very hard cermet cu~ting inserts which are typically com-prised of tungsten carbide and are mounted in the cone to yro~ect outwardly therefrom. Such a rock bit having cutter cones containing tungsten carbide cutter inserts is shown, for exarnple, in United States Patent No. 4,358,384 wherein the general mechanical structure of the roc~ bit is also descxibed.
The cutter inserts, which typically have a cylindrical base, are usually mounted through an interference fit into matching openings in the cutter cone. This method, however, of mounting the cutter inserts to the cone is not entirely satis-factory because the inserts are often dislodged from the cone by excessive force, repetitive loadings or shocks which unavoidably occur during drilling.
Another problem encountered in the manufacture of rock bits, relates to the number of machining and other steps required to fabricate the cutter cone. Conventional cutter cones are fabricated in several machining operations, which are, generally speaking, labor intensive and expensive.
:~2~3~3 Furthermore, the internal portion of the cutter cone includes a friction bearing wherethrough the cone is mounted to the respective journal. It also includes bearing races for balls to retain the cone on the journal. These internal bearing surfaces of the cone must be sufficiently hard to avoid undue wear and to support the loads encountered in drilling. To accomplish this, it has been customary in the prior art to selectively carburise certain pre-machined internal surfaces of the cone.
None of the prior art processes are entirely satisfactory from the standpoint of providing rock bit cutter cones in sufficiently simple (and therefore inexpensive~
procedures with sufficient ability to retain the cutter inserts under severe load conditions.
SUMMARY OF THE INVENTION
The cutter cone according to the invention has a tough shock resistant core, and hard, cuttin~ inserts fi~ted in cavities provided in the core. A hard cladding is disposed on the outer surface of the cone having been metallurgically bonded thereto, preferably in a suitable mold by a powder metallurgy process.
Preferably, metallurgical bonding of the cladding occurs through hot isostatic pressing. The cu~ting inserts are also metallurgically bonded to the core and to the cladding as a result of the formation of the cladding through hot isostatic pressing or like powder mctallurgy processes.
~2~
The interior of the cone incorporates conventionally machined bearing surfaces and races for attachment of the cutter cone to a respective journal of the rock bit~ As a preferred alternative, however, the bearing surfaces and bearing races are forrned in the interior of the cone from a metal powder or cermet in the same or similar powder metallurgical bonding process wherein the exterior cladding is bonded and hardened. As still another alternative, the bearing surfaces are formed in a separate piece which is subsequently affixed into a bearing cavity provided in the core.
In order to prevent degradation of the cutting inserts into undesirable "eta" phase, by diffusion of carbon from the insert into the underlying core during the powder metallurgical bonding process, and to accomodate the mismatch in thermal expansion coefficients between the cuttin~ insert and the ferrous core body, a thin coating of a suitable material is deposited on the inserts prior to placement of the inserts int-o corlesponding cavities in the core. Examples of such material are copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, pa.lladium, palladium alloys, platinum platinum alloys, and nickel or nickc;l alloys.
~ nother alternative to prevent degradation of the cutting inserts .is to provide an alternate source of carbon such as a graphite laycr, in the vicinity of the cuttinc3 inserts.
~3~
According to the present invention there is provided a cutter member of a rock bit comprising:
a core including a plurality of cavities on its exterior surface;
a plurality of hard cutter inserts in the cavities in the core;
a powder metallurgy cladding metallurgically bonded on the exterior surface oE the core, and being metallurgically bonded ko the cutter inserts for retaininy the cutter inserts in the core; and means disposed on the cutter inserts for substantially preventing diffusion of carbon from the cutter inserts into the core and the cladding during heating of the cladding for metallurgically bonding the same to the core.
Also according to the present invention there is provided a process for making a cutter member of rock bit having a plurality of tungsten-carbide cutter inserts, the process being characterized by the steps of:
depositing a thin layer of a material selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, go:Ld, gold alloys, palladiurn, palladium alioys, platinum, platinum alloys, and nickel or nickel alloys on a plurality o~ cutter lnserts;
. ,~
-placing the plurality of cutter inserts into cavities formed in the outer surface of a solid core of t~le cutter member, depositing a powder composition on the outer s-lrface of the core so as to partially embed the cutter inserts;
presslng the powder in a mold to substantially conform to the to the desired final exterior configuration of the cutter melrlber; and heating the powder to metallurgically bond said powder to the melnber and thereby provide an exterior cladding of the cutter member Eor retaining the cutter inserts in the cavities.
Further to the present invention there is provided a process Eor securing at least one cemented carbide body to a steel body comprising the steps of:
depositing a thin layer oE a material selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, nickel and nickel alloys on such a carbide body;
placing such the carbide body into a cavity formed in the outer surface of a solid body of steel, the cavity being di.rnensioned to accept the cemented carbide body without sllbstantial interference;
applying a powder composition on the outer surEace oE the steel body so as to partially ernbed the cemented carbide body;
pressing the powder in a mold to substantiall.y conEorm to a desired Einal exterior conEiguration; and - Sa ~`
heating the powder to metallurgically bond said powder to the steel body and thereby provide an exterior cladding of the steel body for retaining the carbide body in the cavity.
Further to the present invention there is provided a cutter member oE a rock bit, comprising:
a core, including an interior opening, wherethrough the cutter Inernber rnay be mounted to a pin connected to a drill string, sa:id core also including, on its exterior surEace, a plurality of cavities;
a plurality of hard cutter inserts, the cavities and the cutter inserts having substantially matching dimensions so that the cutter inserts are accommodated in the cavities without substantial interference;
a cladding disposed on the exterior surface of the core, the cladding having been deposited by a powder metallurgy technique including a step wherein compacted powder o~ the cladding is heated to metallurgically bond said powder to the core, the cladding being substantially harder than the core, said cladding partially embedding the cutter inserts and rneta:Lluryically bonding sai.d inserts to thC core and to the c.ladd.ing, and means disposed on the cutter inserts for substantially preventing diffusion Oe carbon fcom the cutter inserts into the core and the cladding during the step wherein compacted powder of the c.ladcliny is heated to metallurgically bond the same to the core.
~1 - 5b 3~
Further to the present invention there is provided a cutter cone of a rock drilling bit used for drilling in subterranean forrnations and adaptecl for mounting to a journal leg of the rock drilling bit~ the cone comprising:
A tough, shock-resistant steel core having an interior opening wherethrough the cone is rotatably mounted to the journal, and a plurality of cavities disposed on its exterior surface;
a plurality of hard cutter inserts comprising tungsten-carbide and being dimensioned Eor mounting into the exterior cavities of the core without substantial interference;
a cladding comprising material selected from a group consisting of tool steel and cermets, said cladding substantially coverng the exterior surface of the core, partially embedding the cutter inserts and being metalurgically bonded thereto, having a hardness of at least 50 Rockwell C hardness units and having been deposited on the core by a powder metallurgy process, including a step of placing a suitable powder on the exterior surface of the core to which the inserts are mounted, and heating the powder to metallllrgically bond the powder to the core, the cladding having substantially 100 percent density, and a coating disposed on the cutter inserts comprising a material. which substantially prevents difEusion of carbon from the cutter inserts into the core during the powder metallurgy process.
Further to the present invention there is pcovided a cutter cone rotatably mountable on a journal oE a rock bit oE the type having a plurality of journals disposed anc3ll1arly relative to the rotational axis of the rock bit, the cone comprising:
- 5c -3~
a tough~ shock-resistant, solid steel core, the core having ar, interior opening wherethrough the cone is mounted on its respective journal, the core also having means disposed on its surface for accepting, through a slip fit, a plurality of cutter inserts;
a plural.ity of tungsten-carbide cutter inserts, each of the cutter inserts being mounted into the means disposed on the exter:ior surface of the core;
an exterior cladding disposed on the core partially embeddirly the cutter inserts, having a hardness of at least 50 Rockwell C units, said cladding having been deposited on the core by a powder metallurgy process including a step wherein a suitable metal powder is heated under high isostatic pressure to metallurgically bond said powder to the core and to metallurgically bond the cutter inserts to the core and cladding, and a thin layer of a diffusion preventing metal disposed between each cutter insert and the core, said layer comprislng means for preventing diffusion of carbon from the tungsten-carbide insert into the core during the step of heating under high isostatic pressure.
Further to the present invention there is provided a process for makin~ a cutter member of a rock bit of the type rnounted throu~h a pln to a drill string, the cutter member having a plurality o~ tungsten-carbide cutter inserts, the process compr;.sincJ the steps o~:
'\~
~ 5cl -~3~
depositing a thin layer of a material selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, nickel, and nickel allo~s on the cutter inserts;
after said step of depositing, placing a plurality of the cutter inserts into cavities formed in the outer surface of the sol:id core of the cutter member, said cavities being dimensioned to accept the cutter inserts without substantial interference;
depositing a suitable powder composition on the outer surface of the core so as to partially embed the cutter inserts, and heating and pressing the powder in a suitable mold to metallurgically bond said powder and said cutter inserts to the member and thereby to provide an exterior cladding of the cutter member, said cladding having a hardness of at least 50 Rockwell C
units, substantially conforming to the desired final exterior configuration of the cutter member, and being comprised of a Material selected from a group consisting of metals and cermets.
Further to the present invention there is provided a cutter cone to be mounted on a journal of a rock bit comprising:
a solid core including an interior opening wherethrough the cutter cone may be rotatably mounted to a journal o the rock bit, said core also inclucling, on its exterior surface, a p:Lurality o cavities;
a plurality o~ hard cutter inserts in the cavit:ies in the core, and - 5e _\
~.2~3~3~
a powder metallurgy cladding metallurgically bonded on the exterior surface of the core, and comprising means for rnetallurgically bonding the cutter inserts to the core and to the cladding and for Letaining the cutter inserts in the core.
Further to the present invention there is provided a process for making a cutter cone for a rock bit of the type having at least one journal on which the cutter cone is rotatably rrlounted, the cutter cone having a plurality of cutter i.nserts, the process cornprising the steps of:
placing a plurality of cutter inserts into cavities Eormed in the outer surface of a solid core of the cutter cone;
depositing a powder composition on the outer surface of the solid core so as to partially embed the cutter inserts, pressing the powder in a mold to substantially conform to the desired final exterior configuration of the cutter cone, and heating the powder to bond said powder to the cone, an exterior cladding of the cutter cone being formed in said steps of heating and pressing, and said cladding serving as means for retaining and metallurgically bonding the cutter inserts in the cavities.
~t~,l - 5f -~3~
The features of present invention can be best under-stood, together with further objeets and advantages, from the following deseription taken together with the appended drawings wherein like numerals indicate like parts.
BRIEF DESCRIPTION OF THE DRAWINGS
Fiqure 1 is a perspective view of a rock bit ineor-por~ting the cutter cone of the present invention.
Figure 2 is a eross seetional view of a journal leg of ~ rock bit with the cutter cone of the present invention mounted thereon;
Figure 3 is a schematie eross sectional view of an intermediate in the fabrication of the cutter cone of the present invention, the intermediate having a solid core;
Figure 4 is a schematie cross-seetional view of an intermediate in the process of fabricating another embodiment of the eutter cone of the present invention;
Figure 5 is a schematie eross-sectional view of a tungsten carbide cobalt (cermet3 insert coated with a layer of nickel, which is encorporated in the cutter cone of the present invention, and Figure 6 is schematie representation of a Scanning Electron Microscope (SE~) micrograph of the boundary layers between the tungsten carbide cobalt insert and a nick~l coating on the cne hand, and the nickel coating and underlying mild steel core, cn the other hand.
3~
D~SCRIPTION O~ TH~ PREF~RRED E~iBODI~NTS.
Referring now to the drawing figures, the perspective view of Figure 1 shows a rock bit 8 wherein a cutter cone of the present invention is mounted. The cross-sectional view of Figure 2, shows mountinq of a first embodiment of the cutter cone 10 of the present invention to a journal leg or journal 12 of the rock bit 8.
It should be noted at the outset, that the mechanical configurations of the rock bit 8, the journal 12 and of the cutter cone 10 are conventional in many respects, and therefore need to be disclosed here only to the extent they differ from well known features of conventional rock bits. For a descrip-tion of the conventional features of a rock bit, the specifica-tion of United States Patent No. 4,358,384 is incorporated herein by reference.
For the purpose of explaining the several features of the cut-ter cone, it is deemed to sufficient to note that, in conventional rock bit cons:ruction internal friction bearing surfaces 14 and ball races 1;i are lubricated by an internal supply of a lubricant ~not shown). The bearing surfaces 14 and ball races 16 are sealed from extraneous material, such as drilling mud and drilling debris, by a suitable seal, such as an elastic O-ring seal 20. The conventional internal bearings are usually of the "hard-on-soft" type; e~g. a hard metal bearing surface of the journal 12 engages a bronze bearing surface ~4 of the cutter cone 10~
~3~
Furthermore, in conventional cutter cone construction, a plurality of tungsten carbide cobalt (cerme~) cutter inserts 26 are interference fitted into corresponding circular holes which are drilled individually in the cutter cone 10. This procedure is not only labor intensive, but provides a cutter cone which may have, under severe drilling conditions, less than ad~q~late retention of the cutter inserts 26.
~ eferring now principally to Figure 3, a solid core 28 o~ the cutter cone 10 is shown in a first embodiment. The core
Rock bits used for drilling in subterranean fo~nations when prospecting for oil, gas or minerals, have a main body which is connected to a drill string, and a plurality, typically three, cutter cones rotatably mounted on journals. The journals extend at an angle from the main body of the rocX bit~
As the main body of the rock bit is rotated either from the surface through the drill string, or by a downhole motor, the cutter cones rotate on their resyective journals.
During their rotation, teeth provided in the cones come into contact with the subterranean formation, and provide the drill-ing action.
As is known, the subterranean environment is often very harsh. Highly abrasive drilling mud is continuously circulated from the surface to remove debris of the drilling, and for other purposes. Furthermore, the suhterranean for-mations are composed of rock with a wide range of compressive strength and abrasiveness.
Generally speaking, the prior art has provided two types of cutter cones to cope with the above-noted conditions and to perform the above-noted drilling operations. The first typc of drilling cone is known as "milled-tooth" cone becausc the cone has relatively sharp cutting teeth obtained by appro-priate rnilling of the cone hody. Milled tooth cones, generally ~ ,, J
33~
have a short life and are used ~or drilling in low compressive strength (soft) subterran~an formations.
A second type of cutter cone, used for drilling in higher compressive strength (harder) formations, has a plurality o very hard cermet cu~ting inserts which are typically com-prised of tungsten carbide and are mounted in the cone to yro~ect outwardly therefrom. Such a rock bit having cutter cones containing tungsten carbide cutter inserts is shown, for exarnple, in United States Patent No. 4,358,384 wherein the general mechanical structure of the roc~ bit is also descxibed.
The cutter inserts, which typically have a cylindrical base, are usually mounted through an interference fit into matching openings in the cutter cone. This method, however, of mounting the cutter inserts to the cone is not entirely satis-factory because the inserts are often dislodged from the cone by excessive force, repetitive loadings or shocks which unavoidably occur during drilling.
Another problem encountered in the manufacture of rock bits, relates to the number of machining and other steps required to fabricate the cutter cone. Conventional cutter cones are fabricated in several machining operations, which are, generally speaking, labor intensive and expensive.
:~2~3~3 Furthermore, the internal portion of the cutter cone includes a friction bearing wherethrough the cone is mounted to the respective journal. It also includes bearing races for balls to retain the cone on the journal. These internal bearing surfaces of the cone must be sufficiently hard to avoid undue wear and to support the loads encountered in drilling. To accomplish this, it has been customary in the prior art to selectively carburise certain pre-machined internal surfaces of the cone.
None of the prior art processes are entirely satisfactory from the standpoint of providing rock bit cutter cones in sufficiently simple (and therefore inexpensive~
procedures with sufficient ability to retain the cutter inserts under severe load conditions.
SUMMARY OF THE INVENTION
The cutter cone according to the invention has a tough shock resistant core, and hard, cuttin~ inserts fi~ted in cavities provided in the core. A hard cladding is disposed on the outer surface of the cone having been metallurgically bonded thereto, preferably in a suitable mold by a powder metallurgy process.
Preferably, metallurgical bonding of the cladding occurs through hot isostatic pressing. The cu~ting inserts are also metallurgically bonded to the core and to the cladding as a result of the formation of the cladding through hot isostatic pressing or like powder mctallurgy processes.
~2~
The interior of the cone incorporates conventionally machined bearing surfaces and races for attachment of the cutter cone to a respective journal of the rock bit~ As a preferred alternative, however, the bearing surfaces and bearing races are forrned in the interior of the cone from a metal powder or cermet in the same or similar powder metallurgical bonding process wherein the exterior cladding is bonded and hardened. As still another alternative, the bearing surfaces are formed in a separate piece which is subsequently affixed into a bearing cavity provided in the core.
In order to prevent degradation of the cutting inserts into undesirable "eta" phase, by diffusion of carbon from the insert into the underlying core during the powder metallurgical bonding process, and to accomodate the mismatch in thermal expansion coefficients between the cuttin~ insert and the ferrous core body, a thin coating of a suitable material is deposited on the inserts prior to placement of the inserts int-o corlesponding cavities in the core. Examples of such material are copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, pa.lladium, palladium alloys, platinum platinum alloys, and nickel or nickc;l alloys.
~ nother alternative to prevent degradation of the cutting inserts .is to provide an alternate source of carbon such as a graphite laycr, in the vicinity of the cuttinc3 inserts.
~3~
According to the present invention there is provided a cutter member of a rock bit comprising:
a core including a plurality of cavities on its exterior surface;
a plurality of hard cutter inserts in the cavities in the core;
a powder metallurgy cladding metallurgically bonded on the exterior surface oE the core, and being metallurgically bonded ko the cutter inserts for retaininy the cutter inserts in the core; and means disposed on the cutter inserts for substantially preventing diffusion of carbon from the cutter inserts into the core and the cladding during heating of the cladding for metallurgically bonding the same to the core.
Also according to the present invention there is provided a process for making a cutter member of rock bit having a plurality of tungsten-carbide cutter inserts, the process being characterized by the steps of:
depositing a thin layer of a material selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, go:Ld, gold alloys, palladiurn, palladium alioys, platinum, platinum alloys, and nickel or nickel alloys on a plurality o~ cutter lnserts;
. ,~
-placing the plurality of cutter inserts into cavities formed in the outer surface of a solid core of t~le cutter member, depositing a powder composition on the outer s-lrface of the core so as to partially embed the cutter inserts;
presslng the powder in a mold to substantially conform to the to the desired final exterior configuration of the cutter melrlber; and heating the powder to metallurgically bond said powder to the melnber and thereby provide an exterior cladding of the cutter member Eor retaining the cutter inserts in the cavities.
Further to the present invention there is provided a process Eor securing at least one cemented carbide body to a steel body comprising the steps of:
depositing a thin layer oE a material selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, nickel and nickel alloys on such a carbide body;
placing such the carbide body into a cavity formed in the outer surface of a solid body of steel, the cavity being di.rnensioned to accept the cemented carbide body without sllbstantial interference;
applying a powder composition on the outer surEace oE the steel body so as to partially ernbed the cemented carbide body;
pressing the powder in a mold to substantiall.y conEorm to a desired Einal exterior conEiguration; and - Sa ~`
heating the powder to metallurgically bond said powder to the steel body and thereby provide an exterior cladding of the steel body for retaining the carbide body in the cavity.
Further to the present invention there is provided a cutter member oE a rock bit, comprising:
a core, including an interior opening, wherethrough the cutter Inernber rnay be mounted to a pin connected to a drill string, sa:id core also including, on its exterior surEace, a plurality of cavities;
a plurality of hard cutter inserts, the cavities and the cutter inserts having substantially matching dimensions so that the cutter inserts are accommodated in the cavities without substantial interference;
a cladding disposed on the exterior surface of the core, the cladding having been deposited by a powder metallurgy technique including a step wherein compacted powder o~ the cladding is heated to metallurgically bond said powder to the core, the cladding being substantially harder than the core, said cladding partially embedding the cutter inserts and rneta:Lluryically bonding sai.d inserts to thC core and to the c.ladd.ing, and means disposed on the cutter inserts for substantially preventing diffusion Oe carbon fcom the cutter inserts into the core and the cladding during the step wherein compacted powder of the c.ladcliny is heated to metallurgically bond the same to the core.
~1 - 5b 3~
Further to the present invention there is provided a cutter cone of a rock drilling bit used for drilling in subterranean forrnations and adaptecl for mounting to a journal leg of the rock drilling bit~ the cone comprising:
A tough, shock-resistant steel core having an interior opening wherethrough the cone is rotatably mounted to the journal, and a plurality of cavities disposed on its exterior surface;
a plurality of hard cutter inserts comprising tungsten-carbide and being dimensioned Eor mounting into the exterior cavities of the core without substantial interference;
a cladding comprising material selected from a group consisting of tool steel and cermets, said cladding substantially coverng the exterior surface of the core, partially embedding the cutter inserts and being metalurgically bonded thereto, having a hardness of at least 50 Rockwell C hardness units and having been deposited on the core by a powder metallurgy process, including a step of placing a suitable powder on the exterior surface of the core to which the inserts are mounted, and heating the powder to metallllrgically bond the powder to the core, the cladding having substantially 100 percent density, and a coating disposed on the cutter inserts comprising a material. which substantially prevents difEusion of carbon from the cutter inserts into the core during the powder metallurgy process.
Further to the present invention there is pcovided a cutter cone rotatably mountable on a journal oE a rock bit oE the type having a plurality of journals disposed anc3ll1arly relative to the rotational axis of the rock bit, the cone comprising:
- 5c -3~
a tough~ shock-resistant, solid steel core, the core having ar, interior opening wherethrough the cone is mounted on its respective journal, the core also having means disposed on its surface for accepting, through a slip fit, a plurality of cutter inserts;
a plural.ity of tungsten-carbide cutter inserts, each of the cutter inserts being mounted into the means disposed on the exter:ior surface of the core;
an exterior cladding disposed on the core partially embeddirly the cutter inserts, having a hardness of at least 50 Rockwell C units, said cladding having been deposited on the core by a powder metallurgy process including a step wherein a suitable metal powder is heated under high isostatic pressure to metallurgically bond said powder to the core and to metallurgically bond the cutter inserts to the core and cladding, and a thin layer of a diffusion preventing metal disposed between each cutter insert and the core, said layer comprislng means for preventing diffusion of carbon from the tungsten-carbide insert into the core during the step of heating under high isostatic pressure.
Further to the present invention there is provided a process for makin~ a cutter member of a rock bit of the type rnounted throu~h a pln to a drill string, the cutter member having a plurality o~ tungsten-carbide cutter inserts, the process compr;.sincJ the steps o~:
'\~
~ 5cl -~3~
depositing a thin layer of a material selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, nickel, and nickel allo~s on the cutter inserts;
after said step of depositing, placing a plurality of the cutter inserts into cavities formed in the outer surface of the sol:id core of the cutter member, said cavities being dimensioned to accept the cutter inserts without substantial interference;
depositing a suitable powder composition on the outer surface of the core so as to partially embed the cutter inserts, and heating and pressing the powder in a suitable mold to metallurgically bond said powder and said cutter inserts to the member and thereby to provide an exterior cladding of the cutter member, said cladding having a hardness of at least 50 Rockwell C
units, substantially conforming to the desired final exterior configuration of the cutter member, and being comprised of a Material selected from a group consisting of metals and cermets.
Further to the present invention there is provided a cutter cone to be mounted on a journal of a rock bit comprising:
a solid core including an interior opening wherethrough the cutter cone may be rotatably mounted to a journal o the rock bit, said core also inclucling, on its exterior surface, a p:Lurality o cavities;
a plurality o~ hard cutter inserts in the cavit:ies in the core, and - 5e _\
~.2~3~3~
a powder metallurgy cladding metallurgically bonded on the exterior surface of the core, and comprising means for rnetallurgically bonding the cutter inserts to the core and to the cladding and for Letaining the cutter inserts in the core.
Further to the present invention there is provided a process for making a cutter cone for a rock bit of the type having at least one journal on which the cutter cone is rotatably rrlounted, the cutter cone having a plurality of cutter i.nserts, the process cornprising the steps of:
placing a plurality of cutter inserts into cavities Eormed in the outer surface of a solid core of the cutter cone;
depositing a powder composition on the outer surface of the solid core so as to partially embed the cutter inserts, pressing the powder in a mold to substantially conform to the desired final exterior configuration of the cutter cone, and heating the powder to bond said powder to the cone, an exterior cladding of the cutter cone being formed in said steps of heating and pressing, and said cladding serving as means for retaining and metallurgically bonding the cutter inserts in the cavities.
~t~,l - 5f -~3~
The features of present invention can be best under-stood, together with further objeets and advantages, from the following deseription taken together with the appended drawings wherein like numerals indicate like parts.
BRIEF DESCRIPTION OF THE DRAWINGS
Fiqure 1 is a perspective view of a rock bit ineor-por~ting the cutter cone of the present invention.
Figure 2 is a eross seetional view of a journal leg of ~ rock bit with the cutter cone of the present invention mounted thereon;
Figure 3 is a schematie eross sectional view of an intermediate in the fabrication of the cutter cone of the present invention, the intermediate having a solid core;
Figure 4 is a schematie cross-seetional view of an intermediate in the process of fabricating another embodiment of the eutter cone of the present invention;
Figure 5 is a schematie eross-sectional view of a tungsten carbide cobalt (cermet3 insert coated with a layer of nickel, which is encorporated in the cutter cone of the present invention, and Figure 6 is schematie representation of a Scanning Electron Microscope (SE~) micrograph of the boundary layers between the tungsten carbide cobalt insert and a nick~l coating on the cne hand, and the nickel coating and underlying mild steel core, cn the other hand.
3~
D~SCRIPTION O~ TH~ PREF~RRED E~iBODI~NTS.
Referring now to the drawing figures, the perspective view of Figure 1 shows a rock bit 8 wherein a cutter cone of the present invention is mounted. The cross-sectional view of Figure 2, shows mountinq of a first embodiment of the cutter cone 10 of the present invention to a journal leg or journal 12 of the rock bit 8.
It should be noted at the outset, that the mechanical configurations of the rock bit 8, the journal 12 and of the cutter cone 10 are conventional in many respects, and therefore need to be disclosed here only to the extent they differ from well known features of conventional rock bits. For a descrip-tion of the conventional features of a rock bit, the specifica-tion of United States Patent No. 4,358,384 is incorporated herein by reference.
For the purpose of explaining the several features of the cut-ter cone, it is deemed to sufficient to note that, in conventional rock bit cons:ruction internal friction bearing surfaces 14 and ball races 1;i are lubricated by an internal supply of a lubricant ~not shown). The bearing surfaces 14 and ball races 16 are sealed from extraneous material, such as drilling mud and drilling debris, by a suitable seal, such as an elastic O-ring seal 20. The conventional internal bearings are usually of the "hard-on-soft" type; e~g. a hard metal bearing surface of the journal 12 engages a bronze bearing surface ~4 of the cutter cone 10~
~3~
Furthermore, in conventional cutter cone construction, a plurality of tungsten carbide cobalt (cerme~) cutter inserts 26 are interference fitted into corresponding circular holes which are drilled individually in the cutter cone 10. This procedure is not only labor intensive, but provides a cutter cone which may have, under severe drilling conditions, less than ad~q~late retention of the cutter inserts 26.
~ eferring now principally to Figure 3, a solid core 28 o~ the cutter cone 10 is shown in a first embodiment. The core
2~ comprises touyh, shock resistant steel, such as mild steel, ~or example A.I.S.I. 9315 steel, or A.I.S.I. 4815 steel. In alternative embodiments, the core 28 itself, may be made by powder metallurgy techniques.
A plurality of cavities 30 are provided in the outer surface 32 of the core 28 to receive, preferably by a sliding fit, a plurality of cutter inserts 26. The cavities 30 may be configured as circular apertures, shown on Figure 3, but may also comprise circumferential grooves (not shown) on the exterior surface 32 of the core 28. Furthermore, the ~utter inserts 26 may be of other than cylindrical configuration. They may be tapered, as is shown on Figure 5, or may have an annulus ~not shown) comprising a protrusion~ Alternatively, the inserts m.l~ be tApered and oval in cross-section. What is important in khis regard is that the cutter inserts 26 are positioned into the cavities 30 without force fitting, or without the need for pre~cision fitting each individual insert 26 into a precisely matching hole, thereby eliminating significant labor and cost.
The cutter inserts 26 are typically made of hard cermet m~teriaL. Ir. accordance with ~sual practice in the art, the ~Z3~
cutter inserts comprise tungsten-carbide cobalt cermet.
~lowever, other cermets which have the required hardness and mechanical properties, may be used. Xuch alternative cermets are tungsten-carbide in iron, iron-nickle, and tungsten-carbide in iron-nickle cobalt. In fact, tungsten-carbide-iron bas~d rnetal cermets often match better the thermal expansion coe~icient of the underlying steel core 28, than t~ngsten-carbide-cobalt cermets.
Subsequent to positioning the cutter inserts 26 into the cavities 30, a powdered metal or cermet composition i5 applied to the exterior surface 32 of the core 28, to eventually become a hard exterior cladding of the eutter cone 10.
The metal or cermet composition is schematically shown on Figure 3 as a layer or cladding bearing the reference num~ral
A plurality of cavities 30 are provided in the outer surface 32 of the core 28 to receive, preferably by a sliding fit, a plurality of cutter inserts 26. The cavities 30 may be configured as circular apertures, shown on Figure 3, but may also comprise circumferential grooves (not shown) on the exterior surface 32 of the core 28. Furthermore, the ~utter inserts 26 may be of other than cylindrical configuration. They may be tapered, as is shown on Figure 5, or may have an annulus ~not shown) comprising a protrusion~ Alternatively, the inserts m.l~ be tApered and oval in cross-section. What is important in khis regard is that the cutter inserts 26 are positioned into the cavities 30 without force fitting, or without the need for pre~cision fitting each individual insert 26 into a precisely matching hole, thereby eliminating significant labor and cost.
The cutter inserts 26 are typically made of hard cermet m~teriaL. Ir. accordance with ~sual practice in the art, the ~Z3~
cutter inserts comprise tungsten-carbide cobalt cermet.
~lowever, other cermets which have the required hardness and mechanical properties, may be used. Xuch alternative cermets are tungsten-carbide in iron, iron-nickle, and tungsten-carbide in iron-nickle cobalt. In fact, tungsten-carbide-iron bas~d rnetal cermets often match better the thermal expansion coe~icient of the underlying steel core 28, than t~ngsten-carbide-cobalt cermets.
Subsequent to positioning the cutter inserts 26 into the cavities 30, a powdered metal or cermet composition i5 applied to the exterior surface 32 of the core 28, to eventually become a hard exterior cladding of the eutter cone 10.
The metal or cermet composition is schematically shown on Figure 3 as a layer or cladding bearing the reference num~ral
3~. As is explained below, one function of the cladding is to retain the insert 26 in the core 28.
The metal or cermet composition comprising the cladding, should satify the following requirements. It should be capable of being hardened and metallurgically bonded to the underlying core 2~ to provide a substaintially one hundred percent dense cladding of a hardness of at least 50 Rockwell C
units. Many tool steel, and cermet compositions satify these recluirements. For example, commercially available, well known, A.~.S.I. D2, M2, M~2, ancl S2 tool and high strength steels are suitable for the cladclincJ. An excellent cladding for the pre~ent invention is the tool steel composition which comprises 2.~5 weig}lt percent carbon, 0.5 percent macJnese, 0.9 percent silicon, 5.25 percent chromium, 9.0 percent vanadium, 1.3 percent molybdenum, 0.07 percent sulphur, with the remainder of ~ _ -~3~
the composition being iron. This composition is well known in the metallurgical arts under the CPM lOV design~ti~n of the Crucible Metals Division of Colt Industries. Still another excellent cladding material is a proprietary alloy of the above-noted Crucible Metals Division, known under the development number 516,892.
Instead of powdered steel compositions, such powdered cerm~ts as tungsten carbide cobalt (WC-Co), titanium-carbide-nickel-molybdenum, (TiC-Ni-Mo) or titanium-carbide-iron alloys (Ferro-TiC alloys) may also be used ~or the cladding 34.
The application of the powdered material of the cladding 3~ and metallurgical bonding to the underlying core 28 and its subsequent hardening are performed in accordance with well known powder metallurgy processes and conventional heat treatment practices. Although these well known processes need not be disclosed here in detail, it is noted that the powder metallurgy processes suitable for use include the use of a mold (not shown) which determines the exterior configuration of the cutter cone 10.
Futhermore, the powder metallurgy proces~ involves application of high pressure to compact the powder, and a step oE heating the powdered cladding in the mold (not shown) at a hiCJh temperature, but below the melting temperature of the powder, to transform the powder into dense metal, or cermet, and to metallurgically bond the same to the underlying core 28.
Thus, the cladding 34 incorporated in the cutter cone lO may be obtained by cold pressing or cold isostatic pressing the powdered layer 3~ on the core 2~, followed by a step of 3~
sintering.
A preferred process for obtaining the hard cladding 34 for th~ cutter cone 10 is, however, hot isostatic pressing (HIPping). Details of this process, including the preparatory steps to the actual hot pressing of the cutter cone 10, are described in United States Patent Nos. 3,700,435 and 3,804,575, the specifications of which are hereby expressly incorporated by ref~rence. When the Crucible CPM-lOV powdered steel composition i~ u.~ed for the cutter cone 10, the hot isostatic pressing step i~ preEerably performed between approximately 1900 to 2000F, ~or approximately 4 to 8 hours, at approximately 15,000 to 30,000 PSI.
After the hot isostatic pressing step, certain further heat treatment steps, well known in the art, such as quenchiny and tempering, are performed on the cutter cone 10. The conditions for quenching and tempering are perferably those recommended by the suppliers of the powdered steel composition which is used for the cladding 34.
Referring still principally to Figures 2 and 3, the cutter cone 10 obtained in the above described manner has an exterior configuration which corresponds to the final, desired configuration of the cutter cone 10 useable in a rock bit. In other words, little, if any, machining is required on the ~xt~r.ior of the cutter cone 10. Thickness of the cladding i5 not critical the cladding may, for example, be 1/8 inch (3.2 mm) th:ick.
~ further, very s.ignificant advantage is that the autter :inserts 26 are affixed to the core 28 and to the cladding 3~ by metallurgical bonds. ~xperience has shown that a tungsten ~ ~3~3~
carbide cob~lt insert (of the size normally used for rock bits, having 0.5" diameter and 0.310" "grip") affixed to the cutter cone 10 as described herein requires on the average a pulling ~orce in excess of 21,000 lbs. to dislodge the insert from the cone lOo In contrast, conventional, interference fitted inserts are dislodged from the cone 10 by a force o~ approximately 7,000 to 10,000 lbs.
1'he cladding 34 of the cone 10 is substantially one hurldred percent (99.995%) dense, and has a surface hardness of at least 50 Rockwell C Units.
rrhe interior of the solid intermediate cutter cone 10 shown on Figure 3 may be machined independently of the hot isostatic pressing process, to provide the cutter cone interior shown on Figure 1. Alternatively, the core 28 itself may be formed by powder metallurgy in steps separate from the above-described steps. Furthermore, conventional, bearing surfaces, for example, aluminum-bronze, or hard metal bearings, for example, cobalt based hard facing alloys may be applied in~o the interior of the cone 10 in accordance with state of the art.
~ s still another alternative, the bearing surfaces may be formed separately from the fabrication of the core 28. In this case, a separate bearing insert piece (not shown) is fitted into the hollow core.
Referring now to Figure 4, a second embodiment of the cutter cone 36 is shown. This embodiment has interior bearing sur~aces 38 and races 40 obtained by a powder metallurgy process, preferably a process including a hot isostatic pressing .step. Thus, in order to obtain the cutter cone~ 36 shown on E'igure 4, a forged mild steel core is provided by a machined ~ ~3~3~3 interior cavity, or opening 42, and a plurality of e~terior cavities or aperatures 30. The exterior aperatures 30 receive cutter inserts 26 in a sliding fit, as it was described in connection with the first embodiment. The exterior cladding 34 is applied to the core 10 in the manner described in connection with the first embodiment.
However, simultaneously with, or subsequent to the powder metallurgy process wherein the cladding 34 (not separately shown in E'igure 4) is bonded, a powdered metal or cermet composition is also bonded in the interior ~avity 42 through a powder metallurgy process, to provide the bearing races 40 and bearing surface 38. In this case, the interior surfaces of the cutter cone 36 emerge fro~l the hot isostatic pressing process in a "near-net" shape, and therefore do not require extensive finish machining.
There is a significant advantage of obtaining very hard bearing surfaces 38 and races 40, such as tungsten-carbide cobalt, in the cutter cone 36. Mamely, when such bearing surfaces and races have "hard" counterparts on the rock bit journal 12, then external lubrication and cooling may be aEfected by circulating drilling mud, rather than by an internal supply of a lubricant. This, of course, eliminates the need for a sealing device such as an 0 ring seal 20 (shown on Figure 2) ancl ~liminates problems associated with degradation or wear of the seal 20. Rock bits having no seal, but rather bearings open to the ambient environment, are known in the art as "open bearing" bits.
Referring now to Figure 5, still another feature of the -improved cutter cone 10 is disclosed. In accordance with this 3~3 feature, the tungsten carbide cobalt cutter inserts 26 have a thin coating or layer 44 of a material which prevents diFfusion of carbon from the tungsten carbide into the underlying steel core 28 during the high temperature hot isostatic pressing or sintering process. As is known, such diffusion has a significant driving force because the carbon content of the steel core 28 typically is low. Loss of carbon from the tungsten carbide results in formation of "eta" phase of the tUnCJsten carbide, which has significantly less desirable mechanical properties than the original tungsten carbide insert.
It was discovered, however, that the above-noted difEusion, undesirable "eta phase" formation, and degradation of mechanical properties of the tungsten carbide inserts 26 may be prevented by providing a layer of copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalu~l tantalum alloys, gold , gold alloys, palladium, palladium alloys, platinum, platinum alloys, and nickel or nickel alloys on the cutter inserts 26 before the inserts 26 are incorporated into the core 28.
-- 1~
~ ~3~3æ
Alternatively, A layer of graphite (not shown) also prevents degradation because it provid~s an alternate source of carbon. A layer of graphite is readily placed on or near the insert 26 for example, by applying a suspension of graphite in a volatile solvent, such as ethanol, on the insert 26. The graphite prevents or reduces diffusion of carbon from the tunysten carbide because it eliminates the driving force of the diffusion.
The other metals noted above, prevent or reduce dif-fusion of carbon by virtue of the limited solubility of carbon in these metals at the temperatures and pressures which occur during the hot isostatic pressing process.
The metal coatings may be applied to the cutter inserts 26 by several methods, such as electroplating, electro-less plating, chemical vapor deposition, plasma deposition and hot dipping. The metal layer or coating 44 on the cutter inserts is preferably approximately 25 to 100 microns (0.001 to 0.004") thic~.
The metal layer 44 deposited on the cutter insert preferably should not melt during the hot isostatic pressing or sintering process. It certainly must not boil during said processes. Nickel or nickel alloys are most preferred materials for the coatiny or layer 44 used in the present invention.
~ 15 The metal coating 44 on the inserts 26 not only prevents the undesirable neta" phase formation in the insert 26, but also provides a transition layer of intermediate thermal expansion coefficient between the tungsten carbide inserts 26 and the surrounding ferrous metal cladding 34 and core 28~ In the absence of such a transition layer the boundary cracks readily. Nevertheless, as it was noted above, test results in the absence of such a metal coating still show significant improvement over non-metallurgically bonded i~serts with regards to the force required to dislodge the inserts 26. Figure 6 schematically illustrates a Scanning Elec~ron Microscope (SEM) micrograph of the boundary layers bétween the tungsten carbide cutter insert 26 and a nickel layer 44 on the one hand, and the nickel layer 44 and the underlying core 28, on the other hand.
The metal or cermet composition comprising the cladding, should satify the following requirements. It should be capable of being hardened and metallurgically bonded to the underlying core 2~ to provide a substaintially one hundred percent dense cladding of a hardness of at least 50 Rockwell C
units. Many tool steel, and cermet compositions satify these recluirements. For example, commercially available, well known, A.~.S.I. D2, M2, M~2, ancl S2 tool and high strength steels are suitable for the cladclincJ. An excellent cladding for the pre~ent invention is the tool steel composition which comprises 2.~5 weig}lt percent carbon, 0.5 percent macJnese, 0.9 percent silicon, 5.25 percent chromium, 9.0 percent vanadium, 1.3 percent molybdenum, 0.07 percent sulphur, with the remainder of ~ _ -~3~
the composition being iron. This composition is well known in the metallurgical arts under the CPM lOV design~ti~n of the Crucible Metals Division of Colt Industries. Still another excellent cladding material is a proprietary alloy of the above-noted Crucible Metals Division, known under the development number 516,892.
Instead of powdered steel compositions, such powdered cerm~ts as tungsten carbide cobalt (WC-Co), titanium-carbide-nickel-molybdenum, (TiC-Ni-Mo) or titanium-carbide-iron alloys (Ferro-TiC alloys) may also be used ~or the cladding 34.
The application of the powdered material of the cladding 3~ and metallurgical bonding to the underlying core 28 and its subsequent hardening are performed in accordance with well known powder metallurgy processes and conventional heat treatment practices. Although these well known processes need not be disclosed here in detail, it is noted that the powder metallurgy processes suitable for use include the use of a mold (not shown) which determines the exterior configuration of the cutter cone 10.
Futhermore, the powder metallurgy proces~ involves application of high pressure to compact the powder, and a step oE heating the powdered cladding in the mold (not shown) at a hiCJh temperature, but below the melting temperature of the powder, to transform the powder into dense metal, or cermet, and to metallurgically bond the same to the underlying core 28.
Thus, the cladding 34 incorporated in the cutter cone lO may be obtained by cold pressing or cold isostatic pressing the powdered layer 3~ on the core 2~, followed by a step of 3~
sintering.
A preferred process for obtaining the hard cladding 34 for th~ cutter cone 10 is, however, hot isostatic pressing (HIPping). Details of this process, including the preparatory steps to the actual hot pressing of the cutter cone 10, are described in United States Patent Nos. 3,700,435 and 3,804,575, the specifications of which are hereby expressly incorporated by ref~rence. When the Crucible CPM-lOV powdered steel composition i~ u.~ed for the cutter cone 10, the hot isostatic pressing step i~ preEerably performed between approximately 1900 to 2000F, ~or approximately 4 to 8 hours, at approximately 15,000 to 30,000 PSI.
After the hot isostatic pressing step, certain further heat treatment steps, well known in the art, such as quenchiny and tempering, are performed on the cutter cone 10. The conditions for quenching and tempering are perferably those recommended by the suppliers of the powdered steel composition which is used for the cladding 34.
Referring still principally to Figures 2 and 3, the cutter cone 10 obtained in the above described manner has an exterior configuration which corresponds to the final, desired configuration of the cutter cone 10 useable in a rock bit. In other words, little, if any, machining is required on the ~xt~r.ior of the cutter cone 10. Thickness of the cladding i5 not critical the cladding may, for example, be 1/8 inch (3.2 mm) th:ick.
~ further, very s.ignificant advantage is that the autter :inserts 26 are affixed to the core 28 and to the cladding 3~ by metallurgical bonds. ~xperience has shown that a tungsten ~ ~3~3~
carbide cob~lt insert (of the size normally used for rock bits, having 0.5" diameter and 0.310" "grip") affixed to the cutter cone 10 as described herein requires on the average a pulling ~orce in excess of 21,000 lbs. to dislodge the insert from the cone lOo In contrast, conventional, interference fitted inserts are dislodged from the cone 10 by a force o~ approximately 7,000 to 10,000 lbs.
1'he cladding 34 of the cone 10 is substantially one hurldred percent (99.995%) dense, and has a surface hardness of at least 50 Rockwell C Units.
rrhe interior of the solid intermediate cutter cone 10 shown on Figure 3 may be machined independently of the hot isostatic pressing process, to provide the cutter cone interior shown on Figure 1. Alternatively, the core 28 itself may be formed by powder metallurgy in steps separate from the above-described steps. Furthermore, conventional, bearing surfaces, for example, aluminum-bronze, or hard metal bearings, for example, cobalt based hard facing alloys may be applied in~o the interior of the cone 10 in accordance with state of the art.
~ s still another alternative, the bearing surfaces may be formed separately from the fabrication of the core 28. In this case, a separate bearing insert piece (not shown) is fitted into the hollow core.
Referring now to Figure 4, a second embodiment of the cutter cone 36 is shown. This embodiment has interior bearing sur~aces 38 and races 40 obtained by a powder metallurgy process, preferably a process including a hot isostatic pressing .step. Thus, in order to obtain the cutter cone~ 36 shown on E'igure 4, a forged mild steel core is provided by a machined ~ ~3~3~3 interior cavity, or opening 42, and a plurality of e~terior cavities or aperatures 30. The exterior aperatures 30 receive cutter inserts 26 in a sliding fit, as it was described in connection with the first embodiment. The exterior cladding 34 is applied to the core 10 in the manner described in connection with the first embodiment.
However, simultaneously with, or subsequent to the powder metallurgy process wherein the cladding 34 (not separately shown in E'igure 4) is bonded, a powdered metal or cermet composition is also bonded in the interior ~avity 42 through a powder metallurgy process, to provide the bearing races 40 and bearing surface 38. In this case, the interior surfaces of the cutter cone 36 emerge fro~l the hot isostatic pressing process in a "near-net" shape, and therefore do not require extensive finish machining.
There is a significant advantage of obtaining very hard bearing surfaces 38 and races 40, such as tungsten-carbide cobalt, in the cutter cone 36. Mamely, when such bearing surfaces and races have "hard" counterparts on the rock bit journal 12, then external lubrication and cooling may be aEfected by circulating drilling mud, rather than by an internal supply of a lubricant. This, of course, eliminates the need for a sealing device such as an 0 ring seal 20 (shown on Figure 2) ancl ~liminates problems associated with degradation or wear of the seal 20. Rock bits having no seal, but rather bearings open to the ambient environment, are known in the art as "open bearing" bits.
Referring now to Figure 5, still another feature of the -improved cutter cone 10 is disclosed. In accordance with this 3~3 feature, the tungsten carbide cobalt cutter inserts 26 have a thin coating or layer 44 of a material which prevents diFfusion of carbon from the tungsten carbide into the underlying steel core 28 during the high temperature hot isostatic pressing or sintering process. As is known, such diffusion has a significant driving force because the carbon content of the steel core 28 typically is low. Loss of carbon from the tungsten carbide results in formation of "eta" phase of the tUnCJsten carbide, which has significantly less desirable mechanical properties than the original tungsten carbide insert.
It was discovered, however, that the above-noted difEusion, undesirable "eta phase" formation, and degradation of mechanical properties of the tungsten carbide inserts 26 may be prevented by providing a layer of copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalu~l tantalum alloys, gold , gold alloys, palladium, palladium alloys, platinum, platinum alloys, and nickel or nickel alloys on the cutter inserts 26 before the inserts 26 are incorporated into the core 28.
-- 1~
~ ~3~3æ
Alternatively, A layer of graphite (not shown) also prevents degradation because it provid~s an alternate source of carbon. A layer of graphite is readily placed on or near the insert 26 for example, by applying a suspension of graphite in a volatile solvent, such as ethanol, on the insert 26. The graphite prevents or reduces diffusion of carbon from the tunysten carbide because it eliminates the driving force of the diffusion.
The other metals noted above, prevent or reduce dif-fusion of carbon by virtue of the limited solubility of carbon in these metals at the temperatures and pressures which occur during the hot isostatic pressing process.
The metal coatings may be applied to the cutter inserts 26 by several methods, such as electroplating, electro-less plating, chemical vapor deposition, plasma deposition and hot dipping. The metal layer or coating 44 on the cutter inserts is preferably approximately 25 to 100 microns (0.001 to 0.004") thic~.
The metal layer 44 deposited on the cutter insert preferably should not melt during the hot isostatic pressing or sintering process. It certainly must not boil during said processes. Nickel or nickel alloys are most preferred materials for the coatiny or layer 44 used in the present invention.
~ 15 The metal coating 44 on the inserts 26 not only prevents the undesirable neta" phase formation in the insert 26, but also provides a transition layer of intermediate thermal expansion coefficient between the tungsten carbide inserts 26 and the surrounding ferrous metal cladding 34 and core 28~ In the absence of such a transition layer the boundary cracks readily. Nevertheless, as it was noted above, test results in the absence of such a metal coating still show significant improvement over non-metallurgically bonded i~serts with regards to the force required to dislodge the inserts 26. Figure 6 schematically illustrates a Scanning Elec~ron Microscope (SEM) micrograph of the boundary layers bétween the tungsten carbide cutter insert 26 and a nickel layer 44 on the one hand, and the nickel layer 44 and the underlying core 28, on the other hand.
Claims (58)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A cutter member of a rock bit comprising:
a core including a plurality of cavities on its exterior surface;
a plurality of hard cutter inserts in the cavities in the core;
a powder metallurgy cladding metallurgically bonded on the exterior surface of the core, and being metallurgically bonded to the cutter inserts for retaining the cutter inserts in the core; and means disposed on the cutter inserts for substantially preventing diffusion of carbon from the cutter inserts into the core and the cladding during heating of the cladding for metallurgically bonding the same to the core.
a core including a plurality of cavities on its exterior surface;
a plurality of hard cutter inserts in the cavities in the core;
a powder metallurgy cladding metallurgically bonded on the exterior surface of the core, and being metallurgically bonded to the cutter inserts for retaining the cutter inserts in the core; and means disposed on the cutter inserts for substantially preventing diffusion of carbon from the cutter inserts into the core and the cladding during heating of the cladding for metallurgically bonding the same to the core.
2. The cutter member of Claim 1 wherein the cladding has a different composition from the core.
3. The cutter member of Claim 1 wherein the cladding is harder than the core.
4. The cutter member of Claims 1, 2 or 3 wherein the cladding has a hardness of at least 50 Rockwell C hardness Units.
5. The cutter member of Claims 1, 2 or 3 wherein the core is a solid steel core.
6. The cutter member of Claim 1 wherein the core comprises mild steel.
7. The cutter member of Claim 6 wherein the material of the core is selected from a group consisting of A.I.S.I. 9315 steel and A.I.S.I. 4815 steel.
8. The cutter member of Claims 1, 2 or 3 wherein the cladding comprises tool steel.
9. The cutter member of Claim 1 wherein the cladding comprises a material selected from a group consisting of D2, M2, M42, S2 tool steel, and a tool steel composition consisting essentially of 2.45 percent carbon, 0.5 percent manganese, 0.9 percent silicon, 5.25 percent chromium, 1.3 percent molybdenum, 9 percent vanadium, 0.07 percent sulfur and 80.53 percent iron.
10. The cutter member of Claim 9 wherein the cladding comprises material selected from tungsten carbide-cobalt cermet, titanium carbide-nickel-molybdenum cermet and titanium carbide-ferro alloy cermets.
11. The cutter member of Claim 1, 2 or 3 wherein the cladding has been metallurgically bonded to the core by a hot isostatic pressing process.
12. The cutter member of Claim 1 wherein the means for preventing diffusion comprises a layer disposed between cutter inserts and the core, the material of which is selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, and nickel or nickel alloys.
13. The cutter member of Claim 12 wherein the layer is approximately 25 to 100 microns thick.
14. The cutter member of Claim 12 or 13 wherein the layer is selected from the group consisting of nickel and nickel alloys.
15. The cutter member of Claim 10, 12, or 13 wherein the solid core comprises a cutter cone having an interior opening for rotable mounting on the journal of a rock bit.
16. The cutter member of claim 15 further comprising a lining incorporated within the interior opening, said lining comprising a bearing surface for rotatably mounting the cone on the journal and being harder than the core.
17. The cutter member of Claim 16 wherein the hard lining has been deposited on the core by a powder metallurgy process.
18. A process for making a cutter member a rock bit having a plurality of tungsten carbide cutter inserts, the process being characterized by the steps of:
depositing a thin layer of a material selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, and nickel or nickel alloys on a plurality of cutter inserts;
placing the plurality of cutter inserts into cavities formed in the outer surface of a solid core of the cutter member, depositing a powder composition on the outer surface of the core so as to partially embed the cutter inserts;
pressing the powder in a mold to substantially conform to the desired final exterior configuration of the cutter member;
and heating the powder to metallurgically bond said powder to the member and thereby provide an exterior cladding of the cutter member for retaining the cutter inserts in the cavities.
depositing a thin layer of a material selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, and nickel or nickel alloys on a plurality of cutter inserts;
placing the plurality of cutter inserts into cavities formed in the outer surface of a solid core of the cutter member, depositing a powder composition on the outer surface of the core so as to partially embed the cutter inserts;
pressing the powder in a mold to substantially conform to the desired final exterior configuration of the cutter member;
and heating the powder to metallurgically bond said powder to the member and thereby provide an exterior cladding of the cutter member for retaining the cutter inserts in the cavities.
19. The process of Claim 18 wherein the cutter inserts are inserted in the cavities without an interference fit.
20. The process of Claim 18 wherein the step of depositing thin layer material on the cutter inserts comprises electroplating.
21. The process of Claims 18, 19 or 20 wherein the material of the thin layer is selected from a group consisting of nickel and nickel alloys.
22. The process of Claims 18, 19 or 20 wherein the powder composition of the cladding is selected from a group consisting of tungsten carbide-cobalt cermet, titanium carbide-nickel-molybdenum cermet, titanium carbide-ferro alloy cermet, D2, M2, M42, S2 tool steels and a tool steel composition consisting essentially of 2.45 percent carbon, 0.5 percent manganese, 0.9 percent silicon, 5.25 percent chromium, 1.3 percent molybdenum, 9 percent vanadium, 0.07 percent sulfur and 80.53 percent iron.
23. The process of Claims 18, 19 or 20 wherein the steps of heating and pressing are conducted as hot isostatic pressing in the range of 15,000 to 30,000 PSI.
24. The process of Claims 18, 19 or 20 and further comprising the step of placing a second powder composition within an interior opening of the core, and pressing and heating the second powder composition to metallurgically bond the same to the core to provide a hard interior bearing surface within said core.
25. A process for securing at least one cemented carbide body to a steel body comprising the steps of:
depositing a thin layer of a material selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, nickel and nickel alloys on such a carbide body;
placing such the carbide body into a cavity formed in the outer surface of a solid body of steel, the cavity being dimensioned to accept the cemented carbide body without substantial interference;
applying a powder composition on the outer surface of the steel body so as to partially embed the cemented carbide body;
pressing the powder in a mold to substantially conform to a desired final exterior configuration; and heating the powder to metallurgically bond said powder to the steel body and thereby provide an exterior cladding of the steel body for retaining the carbide body in the cavity.
depositing a thin layer of a material selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, nickel and nickel alloys on such a carbide body;
placing such the carbide body into a cavity formed in the outer surface of a solid body of steel, the cavity being dimensioned to accept the cemented carbide body without substantial interference;
applying a powder composition on the outer surface of the steel body so as to partially embed the cemented carbide body;
pressing the powder in a mold to substantially conform to a desired final exterior configuration; and heating the powder to metallurgically bond said powder to the steel body and thereby provide an exterior cladding of the steel body for retaining the carbide body in the cavity.
26. The process of claim 25 wherein the step of depositing a thin layer of material on the carbide body comprises electroplating.
27. The process of Claim 25 wherein the material of the thin layer is selected from a group consisting of nickel and nickel alloys.
28. The process of any one of Claims 25 to 27, wherein the powder composition is selected for also metallurgically bonding to the carbide body.
29. The process of any one of Claims 25 to 27, wherein the powder composition of the cladding is selected from a group consisting of tungsten carbide-cobalt cermet, titanium carbide-nickel-molybdenum cermet, titanium carbide-ferro alloy cermet, D2, M2, M42, S2 tool steels and a tool steel composition consisting essentially of 2.45 percent carbon, 0.5 percent manganese, 0.9 percent silicon, 5.25 percent chromium, 9.0 percent vanadium, 1.3 percent molybdenum, 0.07 percent sulfur and 80.53 percent iron.
30. The process of any one of claims 25 to 27, further comprising the step of hardening the cladding to a hardness of at least 50 Rockwell C.
31. The process of any one of claims 25 to 27, wherein the steps of heating and pressing are conducted as hot isostatic pressing in the range of 15,000 to 30,000 PSI.
32. A cutter member of a rock bit, comprising:
a core, including an interior opening, wherethrough the cutter member may be mounted to a pin connected to a drill string, said core also including, on its exterior surface, a plurality of cavities;
a plurality of hard cutter inserts, the cavities and the cutter inserts having substantially matching dimensions so that the cutter inserts are accommodated in the cavities without substantial interference;
a cladding disposed on the exterior surface of the core, the cladding having been deposited by a powder metallurgy technique including a step wherein compacted powder of the cladding is heated to metallurgically bond said powder to the core, the cladding being substantially harder than the core, said cladding partially embedding the cutter inserts and metallurgically bonding said inserts to the core and to the cladding, and means disposed on the cutter inserts for substantially preventing diffusion of carbon from the cutter inserts into the core and the cladding during the step wherein compacted powder of the cladding is heated to metallurgically bond the same to the core.
a core, including an interior opening, wherethrough the cutter member may be mounted to a pin connected to a drill string, said core also including, on its exterior surface, a plurality of cavities;
a plurality of hard cutter inserts, the cavities and the cutter inserts having substantially matching dimensions so that the cutter inserts are accommodated in the cavities without substantial interference;
a cladding disposed on the exterior surface of the core, the cladding having been deposited by a powder metallurgy technique including a step wherein compacted powder of the cladding is heated to metallurgically bond said powder to the core, the cladding being substantially harder than the core, said cladding partially embedding the cutter inserts and metallurgically bonding said inserts to the core and to the cladding, and means disposed on the cutter inserts for substantially preventing diffusion of carbon from the cutter inserts into the core and the cladding during the step wherein compacted powder of the cladding is heated to metallurgically bond the same to the core.
33. The cutter member of claim 32, wherein the means comprise a layer disposed on the cutter inserts, the material of which is selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, nickel, and nickel alloys.
34. The cutter member of claim 33, wherein the layer consists of nickel.
35. The cutter member of claim 34, wherein the layer is approximately 25 to 100 microns thick.
36. The cutter member of claim 34, wherein the cutter inserts comprise a cermet of tungsten-carbide and cobalt.
37. A cutter cone of a rock drilling bit used for drilling in subterranean formations and adapted for mounting to a journal leg of the rock drilling bit, the cone comprising:
a tough, shock-resistant steel core having an interior opening wherethrough the cone is rotatably mounted to the journal, and a plurality of cavities disposed on its exterior surface;
a plurality of hard cutter inserts comprising tungsten-carbide and being dimensioned for mounting into the exterior cavities of the core without substantial interference;
a cladding comprising material selected from a group consisting of tool steel and cermets, said cladding substantially coverng the exterior surface of the core, partially embedding the cutter inserts and being metalurgically bonded thereto, having a hardness of at least 50 Rockwell C
hardness units and having been deposited on the core by a powder metallurgy process, including a step of placing a suitable powder on the exterior surface of the core to which the inserts are mounted, and heating the powder to metallurgically bond the powder to the core, the cladding having substantially 100 percent density, and a coating disposed on the cutter inserts comprising a material which substantially prevents diffusion of carbon from the cutter inserts into the core during the powder metallurgy process.
a tough, shock-resistant steel core having an interior opening wherethrough the cone is rotatably mounted to the journal, and a plurality of cavities disposed on its exterior surface;
a plurality of hard cutter inserts comprising tungsten-carbide and being dimensioned for mounting into the exterior cavities of the core without substantial interference;
a cladding comprising material selected from a group consisting of tool steel and cermets, said cladding substantially coverng the exterior surface of the core, partially embedding the cutter inserts and being metalurgically bonded thereto, having a hardness of at least 50 Rockwell C
hardness units and having been deposited on the core by a powder metallurgy process, including a step of placing a suitable powder on the exterior surface of the core to which the inserts are mounted, and heating the powder to metallurgically bond the powder to the core, the cladding having substantially 100 percent density, and a coating disposed on the cutter inserts comprising a material which substantially prevents diffusion of carbon from the cutter inserts into the core during the powder metallurgy process.
38. The cutter cone of claim 37, wherein the material of the coating is selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, nickel, and nickel alloys.
39. The cutter cone of claim 38, wherein the material of the coating is selected from a group consisting of nickel and nickel alloys.
40. The cutter cone of claim 37, further comprising a hard lining incorporated within the interior opening, said lining comprising a bearing surface for rotatably mounting the cone on the journal.
41. The cutter cone of claim 40, wherein the hard lining has been deposited on the core by a powder metallurgy process.
42. A cutter cone rotatably mountable on a journal of a rock bit of the type having a plurality of journals disposed angularly relative to the rotational axis of the rock bit, the cone comprising:
a tough, shock-resistant, solid steel core, the core having an interior opening wherethrough the cone is mounted on its respective journal, the core also having means disposed on its surface for accepting, through a slip fit, a plurality of cutter inserts;
a plurality of tungsten-carbide cutter inserts, each of the cutter inserts being mounted into the means disposed on the exterior surface of the core;
an exterior cladding disposed on the core partially embedding the cutter inserts, having a hardness of at least 50 Rockwell C units, said cladding having been deposited on the core by a powder metallurgy process including a step wherein a suitable metal powder is heated under high isostatic pressure to metallurgically bond said powder to the core and to metallurgically bond the cutter inserts to the core and cladding, and a thin layer of a diffusion preventing metal disposed between each cutter insert and the core, said layer comprising means for preventing diffusion of carbon from the tungsten-carbide insert into the core during the step of heating under high isostatic pressure.
a tough, shock-resistant, solid steel core, the core having an interior opening wherethrough the cone is mounted on its respective journal, the core also having means disposed on its surface for accepting, through a slip fit, a plurality of cutter inserts;
a plurality of tungsten-carbide cutter inserts, each of the cutter inserts being mounted into the means disposed on the exterior surface of the core;
an exterior cladding disposed on the core partially embedding the cutter inserts, having a hardness of at least 50 Rockwell C units, said cladding having been deposited on the core by a powder metallurgy process including a step wherein a suitable metal powder is heated under high isostatic pressure to metallurgically bond said powder to the core and to metallurgically bond the cutter inserts to the core and cladding, and a thin layer of a diffusion preventing metal disposed between each cutter insert and the core, said layer comprising means for preventing diffusion of carbon from the tungsten-carbide insert into the core during the step of heating under high isostatic pressure.
43. The cutter cone of claim 42, wherein the means disposed on the surface of the cone comprise a plurality of apertures.
44. The cutter cone of claim 42, wherein the material of the cladding is tool steel.
45. The cutter cone of claim 44, wherein the metal of the cladding is selected from a group consisting of D2, M2, M42, S2 tool steel, and a tool steel composition consisting essentially of 2.45 percent carbon, 0.5 percent manganese, 0.9 percent silicon, 5.25 percent chromium, 1.3 percent molybdenum, 9 percent vanadium, 0.07 percent sulphur, and 80.53 percent iron.
46. The cutter cone of claim 45, wherein the metal of the cladding consists essentially of 2.45 percent carbon, 0 5 percent manganese, 0.9 percent silicon, 5.25 percent chromium, 1.3 percent molybdenum, 9 percent vanadium, 0.07 percent sulphur, and 80.53 percent iron.
47. The cutter cone of claim 44, wherein the thin layer of diffusion preventing metal is selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, nickel, and nickel alloys.
48. The cutter cone of claim 47, wherein the thin layer of diffusion preventing metal is deposited on the cutter inserts prior to mounting the cutter inserts into the core.
49. The cutter cone of claim 48, wherein the thin layer of diffusion preventing metal is selected from a group consisting of nickel and nickel alloys, and wherein said layer is approximately 25 to 100 microns thick.
50. A process for making a cutter member of a rock bit of the type mounted through a pin to a drill string, the cutter member having a plurality of tungsten-carbide cutter inserts, the process comprising the steps of:
depositing a thin layer of a material selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, nickel, and nickel alloys on the cutter inserts;
after said step of depositing, placing a plurality of the cutter inserts into cavities formed in the outer surface of the solid core of the cutter member, said cavities being dimensioned to accept the cutter inserts without substantial interference;
depositing a suitable powder composition on the outer surface of the core so as to partially embed the cutter inserts, and heating and pressing the powder in a suitable mold to metallurgically bond said powder and said cutter inserts to the member and thereby to provide an exterior cladding of the cutter member, said cladding having a hardness of at least 50 Rockwell C units, substantially conforming to the desired final exterior configuration of the cutter member, and being comprised of a material selected from a group consisting of metals and cermets.
depositing a thin layer of a material selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, nickel, and nickel alloys on the cutter inserts;
after said step of depositing, placing a plurality of the cutter inserts into cavities formed in the outer surface of the solid core of the cutter member, said cavities being dimensioned to accept the cutter inserts without substantial interference;
depositing a suitable powder composition on the outer surface of the core so as to partially embed the cutter inserts, and heating and pressing the powder in a suitable mold to metallurgically bond said powder and said cutter inserts to the member and thereby to provide an exterior cladding of the cutter member, said cladding having a hardness of at least 50 Rockwell C units, substantially conforming to the desired final exterior configuration of the cutter member, and being comprised of a material selected from a group consisting of metals and cermets.
51. The process of claim 50, wherein the material of the thin layer is selected from a group consisting of nickel and nickel alloys.
52. The process of claim 50, wherein the solid core comprises mild steel.
53. The process of claim 52 wherein the powder composition is selected from a group consisting of tungsten-carbide-cobalt cermet, titanium-carbide-nickel-molybdenum cermet, titanium-carbide-ferro alloy cermet, D2, M2, M42, S2 tool steels, and a tool steel composition consisting essentially of 2.45 percent carbon. 0.5 percent manganese, 0.9 percent silicon, 5.25 percent chromium, 1.3 percent molybdenum, 9 percent vanadium, 0.07 percent sulfur, and 80.53 percent iron.
54. The process of claim 50, further comprising the step of placing a suitable second powder composition within an interior opening of the solid core, and pressing the second powder composition to metallurgically bond the same to the core to provide a hard interior bearing surface within said core.
55. The process of claim 50, wherein the step of heating and pressing is conducted at approximately 15,000 to 30,000 PSI.
56. The process of claim 50, wherein the step of depositing a thin layer of material on the cutter inserts comprises electroplating.
57. a cutter cone to be mounted on a journal of a rock bit comprising:
a solid core including an interior opening wherethrough the cutter cone may be rotatably mounted to a journal of the rock bit, said core also including, on its exterior surface, a plurality of cavities;
a plurality of hard cutter inserts in the cavities in the core, and a powder metallurgy cladding metallurgically bonded on the exterior surface of the core, and comprising means for metallurgically bonding the cutter inserts to the core and to the cladding and for retaining the cutter inserts in the core.
a solid core including an interior opening wherethrough the cutter cone may be rotatably mounted to a journal of the rock bit, said core also including, on its exterior surface, a plurality of cavities;
a plurality of hard cutter inserts in the cavities in the core, and a powder metallurgy cladding metallurgically bonded on the exterior surface of the core, and comprising means for metallurgically bonding the cutter inserts to the core and to the cladding and for retaining the cutter inserts in the core.
58. A process for making a cutter cone for a rock bit of the type having at least one journal on which the cutter cone is rotatably mounted, the cutter cone having a plurality of cutter inserts, the process comprising the steps of:
placing a plurality of cutter inserts into cavities formed in the outer surface of a solid core of the cutter cone;
depositing a powder composition on the outer surface of the solid core so as to partially embed the cutter inserts, pressing the powder in a mold to substantially conform to the desired final exterior configuration of the cutter cone, and heating the powder to bond said powder to the cone, an exterior cladding of the cutter cone being formed in said steps of heating and pressing, and said cladding serving as means for retaining and metallurgically bonding the cutter inserts in the cavities.
placing a plurality of cutter inserts into cavities formed in the outer surface of a solid core of the cutter cone;
depositing a powder composition on the outer surface of the solid core so as to partially embed the cutter inserts, pressing the powder in a mold to substantially conform to the desired final exterior configuration of the cutter cone, and heating the powder to bond said powder to the cone, an exterior cladding of the cutter cone being formed in said steps of heating and pressing, and said cladding serving as means for retaining and metallurgically bonding the cutter inserts in the cavities.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US54492383A | 1983-10-24 | 1983-10-24 | |
| US544,923 | 1990-06-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1231938A true CA1231938A (en) | 1988-01-26 |
Family
ID=24174141
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000466146A Expired CA1231938A (en) | 1983-10-24 | 1984-10-23 | Rock bit cutter cones having metallurgically bonded cutter inserts |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0142941B1 (en) |
| CA (1) | CA1231938A (en) |
| DE (1) | DE3478627D1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4597456A (en) * | 1984-07-23 | 1986-07-01 | Cdp, Ltd. | Conical cutters for drill bits, and processes to produce same |
| US4562892A (en) * | 1984-07-23 | 1986-01-07 | Cdp, Ltd. | Rolling cutters for drill bits |
| US4708752A (en) * | 1986-03-24 | 1987-11-24 | Smith International, Inc. | Process for laser hardening drilling bit cones having hard cutter inserts placed therein |
| US5038640A (en) * | 1990-02-08 | 1991-08-13 | Hughes Tool Company | Titanium carbide modified hardfacing for use on bearing surfaces of earth boring bits |
| CN101144370B (en) * | 2007-10-24 | 2010-12-08 | 中国地质大学（武汉） | Hot pressing high phosphorus iron base diamond drilling bit and preparation method thereof |
| CN103042208B (en) * | 2013-01-22 | 2015-06-10 | 广东新劲刚新材料科技股份有限公司 | Iron and titanium carbide mixture and method for manufacturing coating on surface of cold pressing mold |
| EP2821166B1 (en) * | 2013-07-04 | 2016-04-20 | Sandvik Intellectual Property AB | A method for manufacturing a wear resistant component comprising mechanically interlocked cemented carbide bodies |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB449974A (en) * | 1935-04-29 | 1936-07-08 | John Corstorphine | An improved boring and drilling tool |
| US2999309A (en) * | 1955-04-06 | 1961-09-12 | Welded Carbide Tool Company In | Composite metal article and method of producing |
| US3444613A (en) * | 1965-11-24 | 1969-05-20 | Coast Metals Inc | Method of joining carbide to steel |
| US4172395A (en) * | 1978-08-07 | 1979-10-30 | Dresser Industries, Inc. | Method of manufacturing a rotary rock bit |
| DE3030010C2 (en) * | 1980-08-08 | 1982-09-16 | Christensen, Inc., 84115 Salt Lake City, Utah | Rotary drill bit for deep drilling |
| SE423562B (en) * | 1980-11-13 | 1982-05-10 | Cerac Inst Sa | PROCEDURE FOR PREPARING A STABLE BODY INCLUDING HARD MATERIAL INSTALLATIONS |
| US4365679A (en) * | 1980-12-02 | 1982-12-28 | Skf Engineering And Research Centre, B.V. | Drill bit |
-
1984
- 1984-10-18 EP EP84307183A patent/EP0142941B1/en not_active Expired
- 1984-10-18 DE DE8484307183T patent/DE3478627D1/en not_active Expired
- 1984-10-23 CA CA000466146A patent/CA1231938A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| EP0142941B1 (en) | 1989-06-07 |
| EP0142941A1 (en) | 1985-05-29 |
| DE3478627D1 (en) | 1989-07-13 |
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