U.S. patent application number 14/590974 was filed with the patent office on 2015-04-30 for diamond bonded construction with reattached diamond body.
The applicant listed for this patent is Smith International, Inc.. Invention is credited to Yuelin Shen, Youhe Zhang.
Application Number | 20150114726 14/590974 |
Document ID | / |
Family ID | 43853945 |
Filed Date | 2015-04-30 |
United States Patent
Application |
20150114726 |
Kind Code |
A1 |
Shen; Yuelin ; et
al. |
April 30, 2015 |
DIAMOND BONDED CONSTRUCTION WITH REATTACHED DIAMOND BODY
Abstract
Diamond bonded construction comprise a diamond body attached to
a support. In one embodiment, an initial substrate used to sinter
the body is interposed between the body and support, and is thinned
to less than 5 times the body thickness, or to less than the body
thickness, prior to attachment to the support to relieve stress in
the body. In another embodiment, the substrate is removed after
sintering, and the body is attached to the support. The support has
a material construction different from that of the initial
substrate, wherein the initial substrate is selected for
infiltration and the support for end use properties. The substrate
and support include a hard material with a volume content that may
be the same or different. Interfaces between the body, substrate,
and/or support may be nonplanar. The body may be thermally stable,
and may include a replacement material disposed therein.
Inventors: |
Shen; Yuelin; (Houston,
TX) ; Zhang; Youhe; (Spring, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Smith International, Inc. |
Houston |
TX |
US |
|
|
Family ID: |
43853945 |
Appl. No.: |
14/590974 |
Filed: |
January 6, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12903081 |
Oct 12, 2010 |
8925656 |
|
|
14590974 |
|
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|
61250813 |
Oct 12, 2009 |
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Current U.S.
Class: |
175/428 |
Current CPC
Class: |
E21B 10/567 20130101;
Y10T 428/30 20150115; E21B 10/5676 20130101; Y10T 428/12042
20150115; Y10T 428/24545 20150115; E21B 10/573 20130101; E21B 10/55
20130101; Y10T 428/249957 20150401; B22F 2005/001 20130101; B22F
7/06 20130101; B24D 99/005 20130101; C22C 26/00 20130101 |
Class at
Publication: |
175/428 |
International
Class: |
E21B 10/567 20060101
E21B010/567; E21B 10/55 20060101 E21B010/55; E21B 10/573 20060101
E21B010/573; B24D 99/00 20060101 B24D099/00 |
Claims
1. A diamond bonded construction comprising: a diamond body
comprising a matrix phase of intercrystalline bonded diamond and a
plurality of interstitial regions dispersed within the matrix
phase, wherein the interstitial regions are substantially free of a
catalyst material used to sinter the diamond body at high
pressure-high temperature conditions; and a support joined to the
diamond body and comprising a constituent that has infiltrated from
the support into a region of the diamond body to fill a population
of the interstitial regions.
2. The diamond bonded construction as recited in claim 1 wherein
the support comprises a material selected from the group consisting
of synthetic diamond, natural diamond, WC, W.sub.2C, TiC, VC, Co,
Ni, Fe, Cu, Group VIII materials, and combinations thereof
3. The diamond bonded construction as recited in claim 2 wherein
the support comprises synthetic diamond or natural diamond.
4. The diamond bonded construction as recited in claim 1 wherein
the diamond body comprises a first region adjacent a top surface of
the diamond body, and a second region adjacent the substrate,
wherein the interstitial regions in the first region are
substantially empty.
5. The diamond bonded construction as recited in claim 4 wherein
the interstitial regions in the diamond body second region contain
a constituent of the support.
6. The diamond bonded construction as recited in claim 5 wherein
the constituent disposed within the interstitial regions in the
diamond body second region comprises diamond.
7. A bit for drilling subterranean formations comprising a body and
a number of cutting elements operatively attached thereto, wherein
one or more of the cutting elements comprises the diamond bonded
construction of claim 1.
8. A diamond bonded construction comprising: a diamond body
comprising a matrix phase of intercrystalline bonded diamond and a
plurality of interstitial regions dispersed within the matrix
phase, wherein interstitial regions are substantially free of a
catalyst material used to sinter the diamond body at high
pressure-high temperature conditions; and a support joined to the
diamond body and comprising synthetic or natural diamond as
combined with a material selected from the group consisting of WC,
W.sub.2C, TiC, VC, Co, Ni, Fe, Cu, Group VIII materials, and
combinations thereof.
9. The diamond bonded construction as recited in claim 8 wherein a
population of the interstitial regions is filled with an infiltrant
material.
10. The diamond bonded construction as recited in claim 9 wherein
the infiltrant material is a constituent of the support.
11. The diamond bonded construction as recited in claim 10 wherein
the infiltrant material comprises diamond.
12. The diamond bonded construction as recited in claim 11 wherein
the population of interstitial regions filled with the infiltrant
material extends within the diamond body from a surface of the
diamond body in contact with the support.
13. The diamond bonded construction as recited in claim 9 wherein
the diamond body comprises a first region comprising interstitial
regions that are empty and disposed adjacent a diamond body top
surface, and a second region comprising the interstitial regions
filled with the infiltrant material and disposed adjacent the
support.
14. A bit for drilling subterranean formations comprising a body
and a number of cutting elements operatively attached thereto,
wherein one or more of the cutting elements comprises the diamond
bonded construction of claim 8.
15. A diamond bonded construction comprising: a diamond body
comprising a matrix phase of intercrystalline bonded diamond and a
plurality of interstitial regions dispersed within the matrix
phase, wherein the interstitial regions are substantially free of a
catalyst material used to sinter the diamond body at high
pressure-high temperature conditions; and a support joined to the
diamond body formed from a material selected from the group
consisting of synthetic diamond, natural diamond, WC, W.sub.2C,
TiC, VC, Co, Ni, Fe, Cu, Group VIII materials, and combination
thereof; wherein the diamond body comprises a first region with
interstitial regions that are substantially empty and a second
region that includes an infiltrant material.
16. The diamond bonded construction as recited in claim 10 wherein
the infiltrant material is diamond.
17. The diamond bonded construction as recited in claim 10 wherein
the support comprises synthetic or natural diamond.
18. The diamond bonded construction as recited in claim 10 wherein
the second region is adjacent the support and the first region is
adjacent a top surface of the diamond body.
19. The diamond bonded construction as recited in claim 15 wherein
an interface between the diamond body and the support is
nonplanar.
20. A bit for drilling subterranean formations comprising a body
and a number of cutting elements operatively attached thereto,
wherein one or more of the cutting elements comprises the diamond
bonded construction of claim 15.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a continuation of U.S.
application Ser. No. 12/903,081, filed Oct. 12, 2010, now U.S. Pat.
No. 8,925,656, issued Jan. 6, 2015, which claims priority to U.S.
Provisional Patent Application 61/250,813, filed on Oct. 12, 2009,
which applications are herein incorporated by reference in their
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention generally relates to diamond bonded
constructions and, more particularly, to diamond bonded
constructions that are specially engineered with a diamond body
that is attached to a substrate other than the one used for
sintering the diamond body at high pressure/high temperature
conditions to provide improved performance properties and service
life when compared to conventional diamond bonded
constructions.
[0004] 2. Background of the Invention
[0005] The use of constructions comprising a body formed from
ultra-hard materials such as diamond, polycrystalline diamond
(PCD), cubic boron nitride (cBN), polycrystalline cubic boron
nitride (PcBN) are well known in the art. An example of such
constructions may be found in the form of cutting elements
comprising an ultra-hard component or body that is joined to a
metallic component or substrate. In such cutting elements, the wear
or cutting portion is formed from the ultra-hard component and the
metallic portion is provided for the purpose of attaching the
cutting element to a desired wear and/or cutting device. In such
known constructions, the ultra-hard component may be formed from
those ultra-hard materials described above that provide a high
level of wear and/or abrasion resistance that is greater than that
of the metallic component.
[0006] The use of PCD as an ultra-hard material for forming such
constructions is well known in the art. PCD is formed by subjecting
a volume of diamond grains to high pressure/high temperature (HPHT)
conditions in the presence of a suitable catalyst material, such as
a solvent catalyst metal selected from Group VIII of the Periodic
table. Oftentimes, the source of the solvent catalyst material used
to form PCD is the substrate, wherein the solvent catalyst material
is present as a constituent of the substrate that migrates
therefrom and infiltrates into the adjacent diamond body during
HPHT processing. The resulting construction is a PCD compact
comprising the PCD body joined to the substrate.
[0007] An issue known to exist with such conventional PCD compact
constructions is the existence of residual stress within diamond
body adjacent the region interfacing with the substrate that is
created during HPHT processing. Such residual stress may cause
cracking within the diamond body when the compact is placed in a
wear or cutting operation that may result in premature compact
failure. Additionally, while the substrates used to make such
conventional PCD compact constructions may have properties desired
to facilitate sintering of the diamond body during HPHT processing,
e.g., properties associated with solvent catalyst metal content
and/or type, such substrates may not have the most desired
properties for the ultimate use of the compact in a wear or cutting
operation, e.g., may not have a desired degree of erosion
resistance, thereby possibly limiting the effective service life of
the compact.
[0008] It is, therefore, desirable that diamond bonded
constructions be constructed in a manner that provides a reduced or
eliminated degree of residual stress when compared to conventional
PCD compact constructions. It is also desired that such diamond
body constructions be constructed in a manner comprising a
substrate having improved end-use service properties when compared
to conventional PCD compact constructions. It is further desired
that such diamond bonded constructions provide these improved
properties without sacrificing desired properties of wear
resistance, abrasion resistance, impact resistance, and fracture
toughness when compared to conventional PCD compact constructions.
It is still further desired that such diamond bonded constructions
be produced in a manner that is efficient and does not involve the
use of exotic materials and/or techniques.
SUMMARY OF THE INVENTION
[0009] Diamond bonded constructions prepared according to
principles of the invention comprise a sintered diamond body that
is attached to a final substrate or support. The diamond body is
sintered under HPHT conditions and comprises a matrix phase of
intercrystalline bonded diamond, and a plurality of interstitial
regions dispersed within the matrix phase. An initial substrate may
be used as a source of a catalyst material for sintering and/or the
catalyst material may be provided in powder form and mixed with the
diamond powder prior to sintering.
[0010] If an initial substrate is used, in one example embodiment
it may remain attached to the diamond body after sintering, and is
thinned a desired amount to reduce residual stress within the
diamond body. In such example embodiment, a final substrate or
support is attached to the remaining portion of the initial
substrate to form the diamond bonded construction. In an example
embodiment it is desired that the thickness of the remaining
portion of the initial substrate be less than about 5 times that of
the diamond body, and more preferably be less than the thickness of
the diamond body.
[0011] In a second example embodiment, the initial substrate is
completely removed from the diamond body, and the diamond body is
subsequently attached to the support to form the diamond bonded
constructions.
[0012] In both embodiments, it is desired that the support have a
material composition that is different than that of the initial
substrate. The support and initial substrate may comprise the same
hard material. The support may have a volume content of hard
material that is the same as or different from the volume content
of the hard material in the substrate before sintering the diamond
body by HPHT process. The diamond bonded construction may comprise
a planar or nonplanar interface between the diamond body and
initial or final substrate, and /or a planar or nonplanar interface
between the remaining substrate portion and the support or support
as needed to provide a desired degree of attachment strength within
the construction.
[0013] Diamond bonded constructions of this invention may comprise
a diamond body that has been treated to render part of or the
entire diamond body thermally stable or substantially free of the
catalyst material used to form the same. All or a portion of the
thermally stable region may include a replacement material disposed
therein.
[0014] Diamond bonded constructions of this invention have a
reduced amount of residual stress when compared to conventional PCD
constructions, thereby enhancing the operating life of such
constructions. Additionally, the ability to provide a construction
having a final substrate or support that is different from the
initial substrate enables the tailoring of the construction to
provide desired infiltration characteristics during diamond body
formation, while at the same time providing superior final
substrate properties to meet particular end-use applications,
thereby further operating to improve effective service life.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] These and other features and advantages of the present
invention will be appreciated as the same becomes better understood
by reference to the following detailed description when considered
in connection with the accompanying drawings wherein:
[0016] FIG. 1 is a cross sectional side view of a diamond bonded
body comprising an initial substrate attached thereto that was used
to sinter the diamond bonded body during HPHT processing;
[0017] FIG. 2 is a cross sectional side view of a diamond bonded
body;
[0018] FIG. 3 is a cross sectional side view of an example
embodiment diamond bonded construction comprising a diamond bonded
body attached to remaining portion of the initial substrate used to
sinter the diamond body, wherein the initial substrate is attached
to a final substrate;
[0019] FIG. 4 is a cross sectional side view of an example
embodiment diamond bonded construction comprising a diamond bonded
body that is attached to a final substrate;
[0020] FIG. 5 is a perspective side view of a shear cutter
comprising the diamond bonded construction;
[0021] FIG. 6 is a perspective side view of a drag bit comprising a
number of the shear cutters of FIG. 5;
[0022] FIG. 7 is a perspective side view of an insert comprising
the diamond bonded construction;
[0023] FIG. 8 is a perspective side view of a rotary cone drill bit
comprising a number of the inserts of FIG. 7; and
[0024] FIG. 9 is a perspective side view of a percussion or hammer
bit comprising a number of the inserts of FIG. 8.
DETAILED DESCRIPTION
[0025] Diamond bonded constructions of this invention comprise a
diamond bonded body formed from polycrystalline diamond (PCD). The
diamond bonded body may include a region of thermally stable
polycrystalline diamond (TSP), wherein such region may or may not
comprise an infiltrant material. In one embodiment, a substrate
used to initially sinter the diamond bonded body is removed
therefrom, and a different final substrate is attached to the
diamond body. In another embodiment, the substrate used to
initially sinter the diamond body remains attached thereto and is
thinned a desired amount before being attached to a different final
substrate or support In such example embodiments, the final
substrate differs from the initial substrate in its material
composition.
[0026] While the body has been described above as a diamond bonded
body, it is to be understood that the body may be formed ultra-hard
materials other than diamond. As used herein, the term "ultra-hard"
is understood to refer to those materials known in the art to have
a grain hardness of about 4,000 HV or greater. Such ultra-hard
materials may include those capable of demonstrating physical
stability at temperatures above about 750.degree. C., and for
certain applications above about 1,000.degree. C., that are formed
from consolidated materials. Such ultra-hard materials may include
but are not limited to diamond, cubic boron nitride (cBN),
diamond-like carbon, boron suboxide, aluminum manganese boride, and
other materials in the boron-nitrogen-carbon phase diagram which
have shown hardness values similar to cBN and other ceramic
materials.
[0027] PCD is an ultra-hard material formed in the manner noted
above by subjecting a volume of diamond grains to HPHT conditions
in the presence of a catalyst material. The catalyst material may
be a solvent catalyst metal, such as one or more selected from
Group VIII of the Periodic table. As used herein, the term
"catalyst material" refers to the material that was initially used
to facilitate diamond-to-diamond bonding or sintering at the
initial HPHT conditions used to form the PCD. PCD has a material
microstructure comprising a matrix phase of intercrystalline bonded
diamond, and a plurality of interstitial regions dispersed within
the matrix phase, wherein the catalyst material is disposed within
the interstitial regions.
[0028] TSP is formed by removing the catalyst material from PCD, so
that the remaining diamond structure is substantially free of the
catalyst material. TSP has a material microstructure characterized
by a matrix phase of intercrystalline bonded diamond, and a
plurality of empty interstitial regions. If desired, the empty
interstitial regions may be filled with a desired replacement or
infiltrant material as described below. Alternatively, TSP may
comprise the catalyst material that has been treated to prevent it
from acting in a catalytic manner when the diamond body is
subjected to high temperature conditions.
[0029] Diamond grains useful for forming the diamond bonded body
may include natural and/or synthetic diamond powders having an
average diameter grain size in the range of from submicrometer in
size to 100 micrometers, and more preferably in the range of from
about 1 to 80 micrometers. The diamond powder may contain grains
having a mono or multi-modal size distribution. In an example
embodiment, the diamond powder has an average particle grain size
of approximately 20 micrometers. In the event that diamond powders
are used having differently sized grains, the diamond grains are
mixed together by conventional process, such as by ball or attritor
milling for as much time as necessary to ensure good uniform
distribution.
[0030] The diamond grain powder is preferably cleaned, to enhance
the sinterability of the powder by treatment at high temperature,
in a vacuum or reducing atmosphere. The diamond powder mixture is
loaded into a desired container for placement within a suitable
HPHT consolidation and sintering device.
[0031] During the HPHT process, a catalyst material, e.g., a
solvent metal catalyst or the like, is combined with the diamond
powder. In a preferred embodiment, the catalyst material is
provided by infiltration from a desired substrate that is
positioned adjacent the diamond powder prior to HPHT processing and
that includes the catalyst material as a constituent material.
Suitable substrates useful for as a source for infiltrating the
catalyst material may include those used to form conventional PCD
materials, and may be provided in powder, green state and/or
already sintered form. A feature of such substrate is that it
includes a metal solvent catalyst that is capable of melting and
infiltrating into the adjacent volume of the diamond powder to
facilitate bonding the diamond grains together during the HPHT
process. In an example embodiment, the catalyst material is Co, and
a substrate useful for providing the same is a cobalt containing
substrate, such as WC-Co.
[0032] Alternatively, the diamond powder may be provided in the
form of a green-state part or mixture comprising diamond powder
that is combined with a binding agent to provide a conformable
material product, e.g., in the form of diamond tape or other
formable/conformable diamond mixture product to facilitate the
manufacturing process. In the event that the diamond powder is
provided in the form of such a green-state part, it is desirable
that a preheating step take place before HPHT consolidation and
sintering to drive off the binder material. In an example
embodiment, the PCD material resulting from the above-described
HPHT process may have diamond volume content in the range of from
about 85 to 95 percent.
[0033] The diamond powder or green-state part is loaded into a
desired container for placement within a suitable HPHT
consolidation and sintering device. The HPHT device is activated to
subject the container to a desired HPHT condition to effect
consolidation and sintering of the diamond powder. In an example
embodiment, the device is controlled so that the container is
subjected to a HPHT process having a pressure of 5,000 MPa or
greater and a temperature of from about 1,350.degree. C. to
1,500.degree. C. for a predetermined period of time. At this
pressure and temperature, the catalyst material melts and
infiltrates into the diamond powder mixture, thereby sintering the
diamond grains to form PCD. After the HPHT process is completed,
the container is removed from the HPHT device, and the so-formed
PCD part is removed from the container.
[0034] FIG. 1 illustrates a PCD construction 10 prepared in the
manner described above comprising a PCD body 12 that is attached to
an initial or infiltration substrate 14 during HPHT processing. The
initial substrate 14 is selected for the purpose of introducing a
desired catalyst material into the diamond volume during the HPHT
process to facilitate desired sintering. An interface surface 16
between the PCD body 12 and the initial substrate 14 may be planar
or nonplanar.
[0035] The PCD body 12 includes top and side surfaces 18 and 20
that may or may not be working surfaces. If desired, the PCD body
12 may have a beveled edge running between the top and side
surfaces. The PCD body may be configured having a desired form for
a particular end-use application without any further shaping or
sizing. Alternatively, the PCD body may initially be configured
having a form that facilitates HPHT processing, and then be
subsequently shaped or sized as desired for use in the end-use
application.
[0036] FIG. 2 illustrates a PCD body 22 without an initial or
infiltrant substrate attached thereto. The infiltration substrate
that was used to form the PCD body (as illustrated in FIG. 1), is
removed from the PCD body after sintering for the purpose of
joining the body to a desired final substrate or support. The PCD
body 22 may include the same surfaces noted above 24 and 26, and
may have a planar or nonplanar substrate interface surface 28.
[0037] FIG. 3 illustrates a example embodiment diamond bonded
construction 30 comprising a diamond bonded body 32 that is
attached to remaining portion 34 of an initial substrate used to
sinter the diamond bonded body. This construction may be formed by
taking the PCD construction illustrated in FIG. 1, and removing a
desired thickness of the initial substrate 34 therefrom by
conventional machining process or the like. In an example
embodiment, the remaining initial substrate 34 is thinned in an
amount that operates to relieve the residual stress existing in the
diamond body from the sintering process a desired amount.
[0038] In such example embodiment, the remaining initial substrate
portion 34 has a thickness that is less than about five times the
thickness of the diamond bonded body 32, and in a preferred
embodiment has a thickness that is less than that of the diamond
bonded body 32. A remaining initial substrate portion 34 having a
thickness that is greater than that of the diamond bonded body may
not provide the degree of residual stress relief in the diamond
bonded body that is desired for a particular end-use application.
Ideally, in this example embodiment, it is desired that the amount
of the initial substrate removed or thinned be an amount that is
effective in providing a desired degree of residual stress relief
in the diamond body. Removing more than this amount may not be
desired as it adds to the cost of manufacturing and/or contributes
to the unwanted waste of materials.
[0039] Referring still to FIG. 3, the construction 30 further
comprises a final substrate or support 36 that is attached or
otherwise joined to the remaining portion 34. An interface surface
38 between the final substrate 36 and the remaining portion 34 may
be planar or nonplanar depending on the particular end-use
application. In an end-use application calling for a high degree of
delamination resistance, a nonplanar interface may be desired to
provide an enhanced degree of attachment strength between the final
substrate and the remaining initial substrate portion. A
construction comprising both a nonplanar interface between the
diamond body and the initial substrate remaining portion, and the
initial substrate and the final substrate may provide a further
degree of enhanced resistance against unwanted delamination during
use.
[0040] In an example embodiment, the final substrate 36 has a
material composition and/or one or more performance properties that
are different from that of an infiltration substrate used to form
the diamond bonded body. Materials useful for forming the final
substrate in such constructions include those useful for forming
infiltrant substrates for making conventional PCD materials, such a
metallic materials, ceramic materials, cermet materials, and
combinations thereof. Example final substrates may be formed from
hard materials like carbides such as WC, W.sub.2C, TiC, VC, or
ultra-hard materials such as synthetic diamond, natural diamond and
the like, wherein the hard or ultra-hard materials may include a
softer binder phase comprising one or more Group VIII material such
as Co, Ni, Fe, and Cu, and combinations thereof
[0041] In an example embodiment, the final substrate may have one
or more material properties making it relatively better suited for
use of the construction in an end-use application than the
infiltration substrate used to initially form the diamond bonded
body. For example, the final substrate may have a material
composition comprising a lesser amount of a binder material, such
as a Group VIII material or the like, than that of the infiltrant
substrate, making it less well suited for infiltration and
sintering purposes, but providing an improved degree of erosion
resistance and thus making it better suited for end-use purposes
that are exposed to erosive conditions.
[0042] In an example embodiment, the PCD construction may be formed
using a WC-Co initial substrate having a WC hard material with a
particle size of about 3 microns and having a Co content of about
14 percent by weight prior to sintering of the diamond body. The
final substrate may have the same WC particle size but a Co content
of about 11 percent by weight. Such an initial substrate includes a
Co content that facilitates infiltration and sintering during HPHT
processing, while such a final substrate has a reduced Co content
that provides a desired improvement in erosion resistance to
facilitate end use. It is understood that this description is
representative of only one example construction, and that initial
and final substrates having constructions and/or properties other
than those described may be used to form diamond bonded
constructions.
[0043] FIG. 4 illustrates an example embodiment diamond bonded
construction 40 comprising a diamond bonded body 42 that is
attached to a final substrate 44. Unlike the construction
embodiment illustrated in FIG. 3, the diamond bonded construction
of FIG. 4 does not include a remaining initial substrate portion.
In an example embodiment, any initial substrate that was used to
sinter the diamond bonded body during HPHT processing is removed,
and the resulting diamond bonded body is attached to the final
substrate 44. The final substrate may be formed from the same types
of materials described above. In this example embodiment, the
diamond bonded body is formed using an initial substrate (as
illustrated in FIG. 1) as the source of the catalyst material for
infiltration, and the infiltrant substrate is subsequently removed
from the so-formed diamond bonded body by conventional method and
prepared for attachment with the final substrate. The initial and
final substrates may be the same as those described above for the
embodiment illustrated in FIG. 3.
[0044] The final substrate may be attached to the diamond bonded
body, in one embodiment, or to a remaining portion of an initial
substrate, in another embodiment, by conventional techniques such
as by diffusion bonding, brazing, or mechanical locking under HPHT
conditions or other appropriate conditions and/or environment. In a
preferred embodiment, the final substrate is attached to the
diamond bonded body or remaining initial substrate portion by HPHT
process to ensure robust bonding and no conversion of diamond into
graphite.
[0045] If desired, the diamond bonded body may be treated to remove
at least a portion of the catalyst material disposed therein,
thereby providing a resulting diamond body having improved
properties of thermal stability. The particular end-use application
will influence the extent and location of catalyst material removed
from the diamond bonded body. The term "removed", as used with
reference to the catalyst material is understood to mean that a
substantial portion of the catalyst material no longer resides
within the treated region of the diamond body. However, it is to be
understood that some small amount of catalyst material may still
remain in the part, e.g., within the interstitial regions and/or
adhered to the surface of the diamond crystals. Additionally, the
term "substantially free", as used herein to refer to the catalyst
material in the treated region of the diamond body, is understood
to mean that there may still be some small/trace amount of catalyst
material remaining within the treated diamond body as noted
above.
[0046] In an example embodiment, the diamond bonded body may be
treated to remove catalyst material by chemical treatment, such as
by acid leaching or aqua regia bath, electrochemical treatment such
as by electrolytic process, by liquid metal solubility, or by
liquid metal infiltration that sweeps the existing catalyst
material away and replaces it with another noncatalyst material
during a liquid phase sintering process, or by combinations
thereof. In an example embodiment, the catalyst material is removed
from the diamond body by an acid leaching technique, such as that
disclosed for example in U.S. Pat. No. 4,224,380. Accelerated
catalyst removal techniques may be used that involved elevated
temperature and/or elevated pressure and/or sonic energy and the
like. The diamond bonded body may be subjected to such treatment
before or after it is attached to the final substrate.
[0047] The treated region of the diamond bonded body comprises a
material microstructure having a polycrystalline diamond matrix
phase made up of a plurality of diamond grains or crystals that are
bonded together, and a plurality of interstitial regions that are
disposed between the matrix phase of bonded together diamond
grains, and that exist as empty pores or voids within the material
microstructure, as a result of the catalyst material being removed
therefrom.
[0048] In an example embodiment, only a partial region of the
diamond body is treated and the treated region extends a desired
depth from a surface, which may be a working surface or the bonding
surface to the substrate, of the diamond bonded body. In an example
embodiment, the depth of such treated region may be about 0.05 mm
or less, or may be about 0.05 to 0.4 mm. The exact depth of the
treated region will depend on the bonding process and/or end-use
application.
[0049] If desired, the treated region of the diamond bonded body
may be further treated so that all or a population of the
interstitial regions within the part, previously empty by virtue of
removing the catalyst material therefrom, are filled with a desired
replacement or infiltrant material. In an example embodiment, such
region may be filled, backfilled or reinfiltrated with a material
that operates to minimize and/or eliminate unwanted infiltration of
material from the final substrate, and/or that operates to improve
one or more properties of the diamond bonded body.
[0050] Example replacement or infiltrant materials useful for
treating the diamond bonded body may include materials selected
from the group including metals, metal alloys, metal carbonates,
carbide formers, i.e., materials useful for forming a carbide
reaction product with the diamond in the body, and combinations
thereof. Example metals and metal alloys include those selected
from Group VIII of the Periodic table, examples carbide formers
include those comprising Si, Ti, B, and others known to produce a
carbide reaction product when combined with diamond at HPHT
conditions. The infiltrant material preferably has a melting
temperature that is within the diamond stable HPHT window, and may
be provided in the form of a powder layer, a green state part, an
already sintered part, or a preformed film. The diamond bonded body
may be infiltrated during or independently of the process used to
attach the diamond bonded body to the final substrate.
[0051] It is to be understood that the material selected to form
the infiltrant material may permit some degree of substrate
constituent infiltration therein, possibly in a sufficient degree
to form a desired attachment bond between the diamond bonded body
and the final substrate, e.g., during an HPHT attachment process.
If desired, the extent of backfilling or infiltrating the diamond
bonded body may be controlled to leave a portion of the treated
diamond bonded body uninfiltrated. This may either be done, for
example, by careful control of the infiltration process or may be
done after the diamond bonded body has been completely infiltrated
by further treating the infiltrated region of the diamond bonded
body to remove the infiltrant from a targeted region. For example,
it may be desired that a surface portion of the diamond bonded
body, and possibly a region extending from such surface, not
include the infiltrant material for the purpose of providing a
desired level of thermal stability, abrasion and/or wear
resistance. In an example embodiment, such a surface portion of the
diamond bonded body may form a surface portion, such as a working
surface, of the final diamond bonded construction.
[0052] A feature of diamond bonded constructions of this invention
is that they have reduced amount of residual stress when compared
to conventional PCD constructions that are formed by using and that
remain attached to a sintering substrate without further
processing. Such reduction in residual stress operates to enhance
the operating life of such constructions. Additionally, such
diamond bonded constructions may be configured having an additional
nonplanar interface, e.g., between the initial and final
substrates, that operates to provide an improved degree of
delamination resistance, further operating to enhance effective
service life. Still further, such diamond bonded constructions
include a final substrate that differs from a substrate used as a
catalyst material infiltrant source during sintering of the diamond
body. In a preferred embodiment, the final substrate is selected to
provide improved end-use properties, such as erosion resistance in
the like, when compared to conventional PCD constructions
comprising only an infiltration substrate, thereby operating to
improve effective service life.
[0053] Diamond bonded constructions of this invention may be used
in a number of different applications, such as tools for mining,
cutting, machining, milling and construction applications, wherein
properties of shear strength, thermal stability, wear and abrasion
resistance, mechanical strength, and/or reduced thermal residual
stress are highly desired. Constructions of this invention are
particularly well suited for forming working, wear and/or cutting
elements in machine tools and drill and mining bits such as roller
cone rock bits, percussion or hammer bits, diamond bits, and
cutting elements such as inserts, shear cutters and the like used
in subterranean drilling applications.
[0054] FIG. 5 illustrates a diamond bonded construction embodied in
the form of a shear cutter 50 used, for example, with a drag bit
for drilling subterranean formations. The shear cutter 50 comprises
a diamond bonded body 54 as described above. The diamond bonded
body is attached to a cutter/final substrate 52. The diamond bonded
body 54 includes a working or cutting surface 56. The cutter
substrate may include a portion of an initial substrate and a final
substrate or may comprise only a final substrate.
[0055] Although the shear cutter in FIG. 5 is illustrated having a
generally cylindrical configuration with a flat working surface
that is disposed perpendicular to an axis running through the shear
cutter, it is to be understood that shear cutters formed from
diamond bonded constructions may be configured other than as
illustrated and such alternative configurations are understood to
be within the scope of this invention.
[0056] FIG. 6 illustrates a drag bit 60 comprising a plurality of
the shear cutters 62 described above and illustrated in FIG. 5. The
shear cutters are each attached to blades 64 that each extend from
a head 66 of the drag bit for cutting against the subterranean
formation being drilled.
[0057] FIG. 7 illustrates an embodiment of a diamond bonded
construction in the form of an insert 70 used in a wear or cutting
application in a roller cone drill bit or percussion or hammer
drill bit used for subterranean drilling. For example, such inserts
70 may be formed from blanks comprising a substrate 72 formed from
one or more of the initial and/or final substrate materials 73
disclosed above, and a diamond bonded body 74 having a working
surface 76. The insert substrate may include a portion of an
initial substrate and a final substrate or may comprise only a
final substrate. The blanks are pressed or machined to the desired
shape of a roller cone rock bit insert.
[0058] Although the insert in FIG. 7 is illustrated having a
generally cylindrical configuration with a rounded or radiused
working surface, it is to be understood that inserts formed from
diamond bonded constructions configured other than as illustrated
and such alternative configurations are understood to be within the
scope of this invention.
[0059] FIG. 8 illustrates a rotary or roller cone drill bit in the
form of a rock bit 78 comprising a number of the wear or cutting
inserts 70 disclosed above and illustrated in FIG. 7. The rock bit
78 comprises a body 80 having three legs 82, and a roller cutter
cone 84 mounted on a lower end of each leg. The inserts 70 may be
fabricated according to the method described above. The inserts 70
are provided in the surfaces of each cutter cone 84 for bearing on
a rock formation being drilled.
[0060] FIG. 9 illustrates the inserts 70 described above as used
with a percussion or hammer bit 86. The hammer bit comprises a
hollow steel body 88 having a threaded pin 90 on an end of the body
for assembling the bit onto a drill string (not shown) for drilling
oil wells and the like. A plurality of the inserts 70 is provided
in the surface of a head 92 of the body 88 for bearing on the
subterranean formation being drilled.
[0061] Other modifications and variations of diamond bonded
constructions and methods of forming the same according to the
principles of this invention will be apparent to those skilled in
the art. It is, therefore, to be understood that within the scope
of the appended claims, this invention may be practiced otherwise
than as specifically described.
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