U.S. patent application number 11/560148 was filed with the patent office on 2007-05-17 for hardfacing materials with highly conforming properties.
Invention is credited to David A. Curry, Jimmy W. Eason, James L. Overstreet, John H. Stevens, Eric C. Sullivan.
Application Number | 20070107942 11/560148 |
Document ID | / |
Family ID | 37734462 |
Filed Date | 2007-05-17 |
United States Patent
Application |
20070107942 |
Kind Code |
A1 |
Overstreet; James L. ; et
al. |
May 17, 2007 |
HARDFACING MATERIALS WITH HIGHLY CONFORMING PROPERTIES
Abstract
An earth-boring bit, and a method of increasing the durability
of the same, which includes the step providing a pliable sheet of a
hardfacing matrix material. The pliable sheet of hardfacing
material has a nickel and chromium matrix combined with a first
element. The first element is selected from a group consisting of
spherical sintered tungsten carbide, spherical cast tungsten
carbide, and metallic glass. The hardfacing matrix material sheet
is placed on a preselected surface of the drill bit. The hardfacing
matrix material sheet is then fusion bonded to the drill bit.
Inventors: |
Overstreet; James L.;
(Tomball, TX) ; Curry; David A.; (The Woodlands,
TX) ; Eason; Jimmy W.; (The Woodlands, TX) ;
Stevens; John H.; (Spring, TX) ; Sullivan; Eric
C.; (Houston, TX) |
Correspondence
Address: |
James E. Bradley;BRACEWELL & GIULIANI LLP
P.O. Box 61389
Houston
TX
77208-1389
US
|
Family ID: |
37734462 |
Appl. No.: |
11/560148 |
Filed: |
November 15, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60737003 |
Nov 15, 2005 |
|
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|
Current U.S.
Class: |
175/57 ; 175/374;
175/375 |
Current CPC
Class: |
E21B 10/46 20130101;
C23C 30/005 20130101 |
Class at
Publication: |
175/057 ;
175/374; 175/375 |
International
Class: |
E21B 10/00 20060101
E21B010/00 |
Claims
1. A method of increasing the durability of a drill bit,
comprising: (a) providing a pliable sheet of a hardfacing matrix
material comprising a nickel and chromium matrix combined with a
first element selected from a group consisting of spherical
sintered tungsten carbide, spherical cast tungsten carbide, and
metallic glass; (b) placing the hardfacing matrix material sheet on
a preselected surface of the drill bit; and (c) fusion bonding the
hardfacing matrix material sheet to the drill bit.
2. The method of claim 1, wherein step (c) is performed by heating
the drill bit and hardfacing matrix material sheet in a furnace at
about 2100 degrees Fahrenheit.
3. The method of claim 1, wherein step (c) is performed by heating
the drill bit and hardfacing matrix material sheet in a furnace at
about 2100 degrees Fahrenheit for a duration of between about five
minutes and about ten minutes.
4. The method of claim 1, wherein in step (b), an adhesive located
on a surface of the hardfacing matrix material sheet secures the
hardfacing matrix material sheet in place relative to the
preselected surface of the drill bit prior to step (c).
5. The method of claim 1, wherein the preselected surface comprises
an outer gage surface.
6. The method of claim 1, wherein the preselected surface comprises
a slot surface between a pair of bit blades.
7. The method of claim 1, wherein the hardfacing matrix material
further comprises a second element, which was not previously
selected as the first element, selected from a group consisting of
spherical sintered tungsten carbide, spherical cast tungsten
carbide, metallic glass, microcrystalline tungsten carbide and
macrocrystalline tungsten carbide.
8. The method of claim 7, wherein the hardfacing matrix material
further comprises a third element, which was not previously
selected as either the first or second elements, selected from a
group consisting of spherical sintered tungsten carbide, spherical
cast tungsten carbide, metallic glass, microcrystalline tungsten
carbide and macrocrystalline tungsten carbide.
9. The method of claim 1, wherein the drill bit is a drag bit.
10. The method of claim 1, wherein the drill bit is a tri-cone
bit.
11. A method of increasing the durability of a drag bit type of
drill bit, the drag bit having a plurality of blades and a slot
formed between each pair of adjacent blades, each of the blades
having a cutting region with cutting elements and a gage surface
free of cutting elements, the method comprising: (a) providing a
sheet of a hardfacing matrix material comprising a nickel and
chromium matrix combined with a first element selected from a group
consisting of spherical sintered tungsten carbide, spherical cast
tungsten carbide, and metallic glass; (b) cutting the sheet of a
hardfacing matrix material into a pattern corresponding to a
preselected surface of the drag bit; (c) adhering the pattern to
the preselected surface of the drag bit; and (d) heating the drill
bit, with the pattern adhered thereto, in order to bond the pattern
to the drag bit.
12. The method of claim 11, wherein the preselected surface
comprises the gage surface.
13. The method of claim 11, wherein the preselected surface
comprises the gage surface and the slot.
14. The method of claim 11, wherein the hardfacing matrix material
further comprises a second element, which was not previously
selected as the first element, selected from a group consisting of
spherical sintered tungsten carbide, spherical cast tungsten
carbide, metallic glass, microcrystalline tungsten carbide and
macrocrystalline tungsten carbide.
15. The method of claim 14, wherein the hardfacing matrix material
further comprises a third element, which was not previously
selected as either the first or second elements, selected from a
group consisting of spherical sintered tungsten carbide, spherical
cast tungsten carbide, metallic glass, microcrystalline tungsten
carbide and macrocrystalline tungsten carbide.
16. An earth-boring bit comprising: a bit body having a bit face at
its lower end and a nozzle opening to the bit face for discharging
drilling fluid from an interior of the bit body; a plurality of
blades formed on and protruding from the bit face that extends
radially outward from a central portion of the bit face to a gage
area at the periphery of the bit body, each blade carrying a
plurality of cutters thereon, and each pair of blades defining a
slot extending therebetween for the passage of drilling fluid and
cuttings; a layer of hardfacing material being bonded to a surface
of the bit body, the hardfacing material being substantially
uniform in thickness and free of weldbeads, the hardfacing material
comprising a nickel and chromium matrix combined with a first
element selected from a group consisting of spherical sintered
tungsten carbide, spherical cast tungsten carbide, and metallic
glass; and a bond region located between the layer of hardfacing
material and the surface of the bit body to which the layer of
hardfacing material is bonded.
17. The earth-boring bit of claim 16, wherein the bond region
comprises nickel and chromium from the layer of hardfacing and iron
from the bit body, the bond region being formed when the layer of
hardfacing is bonded to the surface of the bit body with heat.
18. The earth-boring bit of claim 16, wherein the surface of the
bit body to which the layer of hardfacing is bonded is the gage
surface.
19. The earth-boring bit of claim 16, wherein the surface of the
bit body to which the layer of hardfacing is bonded is the
slot.
20. The earth-boring bit of claim 16, wherein the surface of the
bit body to which the layer of hardfacing is within the nozzle.
Description
RELATED APPLICATIONS
[0001] This nonprovisional patent application claims the benefit of
co-pending, provisional patent application U.S. Ser. No.
60/737,003, filed on Nov. 15, 2005, which is hereby incorporated by
reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates in general to drill bits for well
drilling, and in particular to a metallic hardfacing matrix and
method of applying the metallic hardfacing matrix to drill
bits.
[0004] 2. Background of the Invention
[0005] Rotary well drilling for oil and gas is primarily
accomplished through one of two types of bits. In a rotary cutter
bit, the bit body has typically three rotatable cones or cutters.
The cones rotate on bearing pins and have teeth or tungsten carbide
inserts for disintegrating the earth formation. In the fixed cutter
or drag bit type, the bit body has a face which contains cutting
elements mounted on fixed blades. The cutting elements are
typically polycrystalline diamond. The bit body has drilling fluid
passages with nozzles for discharging drilling fluid through junk
slots that are located between the blades.
[0006] Drag bits are extensively used in directionally drilling,
particularly in the technique referred to as steerable drilling. In
this method, the drill bit is steered in desired directions for
cutting borehole segments as it progresses. A mud motor or turbine
is employed with the bit assembly for rotating the drag bit while
the drill string remains stationary.
[0007] Hardfacing or wear-resistant materials are typically
connected to the outer surfaces of drill bits to help reduce wear
and maintain the efficiency of the drill bit. Commonly used
hardfacing includes tungsten carbide particles that are welded in
place on the outer surface of the drill bit. U.S. Reissue Pat. No.
RE 37,127 provides an in depth discussion of hardfacings, and is
incorporated herein by reference in its entirety. Even with skilled
welders, imperfections can be present due to varying thicknesses of
the weld, shape of the drill bit the hardfacing is being welded
upon, and the beads associated with welding processes. Machining
can be time-consuming and expensive. Moreover, hardfacing was not
welded to inner parts due to narrow clearances and expense.
SUMMARY OF THE INVENTION
[0008] A method of increasing the durability of a drill bit, which
includes the step providing a pliable sheet of a hardfacing matrix
material. The pliable sheet of hardfacing material has a nickel and
chromium matrix combined with a first element. The first element is
selected from a group consisting of spherical sintered tungsten
carbide, spherical cast tungsten carbide, and metallic glass. The
hardfacing matrix material sheet is placed on a preselected surface
of the drill bit. The hardfacing matrix material sheet is then
fusion bonded to the drill bit.
[0009] The fusion bonding can be performed by heating the drill bit
and hardfacing matrix material sheet in a furnace at about 2100
degrees Fahrenheit. The fusion bonding can also be in a furnace at
about 2100 degrees Fahrenheit for a duration of between about five
minutes and about ten minutes.
[0010] In step in which the hardfacing matrix material sheet is
placed on the preselected surfaced, an adhesive located on a
surface of the hardfacing matrix material sheet can secure the
hardfacing matrix material sheet in place relative to the
preselected surface of the drill bit prior to the fusion bonding
step. The preselected surface can comprise an outer gage surface,
and a slot surface between a pair of bit blades. The drill bit can
be a drag bit or a tri-cone bit.
[0011] The hardfacing matrix material can also comprises a second
element, which was not previously selected as the first element.
The second element is selected from a group consisting of spherical
sintered tungsten carbide, spherical cast tungsten carbide,
metallic glass, microcrystalline tungsten carbide and
macrocrystalline tungsten carbide. The hardfacing matrix material
can further comprise a third element, which was not previously
selected as either the first or second elements. The third element
is selected from a group consisting of spherical sintered tungsten
carbide, spherical cast tungsten carbide, metallic glass,
microcrystalline tungsten carbide and macrocrystalline tungsten
carbide.
[0012] A method of increasing the durability of a drag bit type of
drill bit, when the drag bit has a plurality of blades and a slot
formed between each pair of adjacent blades. Each of the blades
have a cutting region with cutting elements and a gage surface free
of cutting elements. The method includes the step of providing a
sheet of a hardfacing matrix material comprising a nickel and
chromium matrix combined with a first element selected from a group
consisting of spherical sintered tungsten carbide, spherical cast
tungsten carbide, and metallic glass. The sheet of a hardfacing
matrix material is cut into a pattern corresponding to a
preselected surface of the drag bit. The pattern is adhered to the
preselected surface of the drag bit. The drill bit, with the
pattern adhered thereto is heated in order to bond the pattern to
the drag bit.
[0013] The preselected surface can be the gage surface. The
preselected surface can be the gage surface and the slot.
[0014] The hardfacing matrix material can also include a second
element, which was not previously selected as the first element.
The second element is selected from a group consisting of spherical
sintered tungsten carbide, spherical cast tungsten carbide,
metallic glass, microcrystalline tungsten carbide and
macrocrystalline tungsten carbide. The hardfacing matrix material
can further include a third element, which was not previously
selected as either the first or second elements. The third element
is selected from a group consisting of spherical sintered tungsten
carbide, spherical cast tungsten carbide, metallic glass,
microcrystalline tungsten carbide and macrocrystalline tungsten
carbide.
[0015] An earth-boring bit includes a bit body with a bit face at
its lower end and a nozzle opening to the bit face for discharging
drilling fluid from an interior of the bit body. A plurality of
blades are formed on and protrude from the bit face. The plurality
of blades extend radially outward from a central portion of the bit
face to a gage area at the periphery of the bit body. Each blade
carries a plurality of cutters thereon. Each pair of blades define
a slot extending therebetween for the passage of drilling fluid and
cuttings. A layer of hardfacing material is bonded to a surface of
the bit body. The hardfacing material is substantially uniform in
thickness and free of weldbeads. The hardfacing material includes a
nickel and chromium matrix combined with a first element selected
from a group consisting of spherical sintered tungsten carbide,
spherical cast tungsten carbide, and metallic glass. A bond region
is located between the layer of hardfacing material and the surface
of the bit body to which the layer of hardfacing material is
bonded.
[0016] The bond region can include nickel and chromium from the
layer of hardfacing and iron from the bit body, and the bond region
can be formed when the layer of hardfacing is bonded to the surface
of the bit body with heat. The surface of the bit body to which the
layer of hardfacing is bonded can be the gage surface. The surface
of the bit body to which the layer of hardfacing is bonded can be
the slot. The surface of the bit body to which the layer of
hardfacing can be within the nozzle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a perspective view showing a drag bit assembly
without hardfacing.
[0018] FIG. 2 is a vertical sectional view of the drag bit assembly
of FIG. 1.
[0019] FIG. 3 is perspective view of a hardfacing material matrix
sheet constructed in accordance with this invention.
[0020] FIG. 4 is top plan view of the hardfacing material matrix
sheet of FIG. 3, showing a pattern to be cut therefrom.
[0021] FIG. 5 is a perspective view showing the drag bit assembly
of FIG. 1, with cutouts from the hardfacing material matrix sheet
of FIG. 3 being attached thereto.
[0022] FIG. 6 is an enlarged sectional view of the interface
between the outer surface of the drag bit assembly of FIG. 1 and
the hardfacing material matrix sheet of FIG. 3 after fusion
bonding.
[0023] FIG. 7 are schematic perspective views of various forms of
spherical cast tungsten carbide in accordance with this
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0024] Referring to FIG. 1, bit assembly 11 has a body 13 on a
lower end. Body 13 has a face 15 on its lower end. A plurality of
blades 17 are formed on and protrude from face 15, with six blades
17 being shown in the drawings. Blades 17 lead outward from a
central portion of face 15 to a gage area at the periphery of body
13. Blades 17 are separated from each other, defining junk slots 19
between them for the passage of drilling fluid and cuttings. Each
blade 17 contains a row of conventional cutters typically
polycrystalline diamond (PCD). Nozzles 23 discharge drilling fluid,
which flows through junk slots 19 and back up the borehole along
with the cuttings. While bit assembly 11 is illustrated as a "drag
bit" or steel-bodied bit, it should be readily apparent to those
skilled in the art that the teachings herein are also applicable to
tri-cone bits, or cast bits, such as those illustrated in FIG. 1 of
U.S. Reissue Pat. No. RE 37,127.
[0025] A set of primary gage pads 25 is integrally formed on the
sides of bit body 13. Each primary gage pad 25 is contiguous with
and, in the embodiment shown, extends longitudinally from one of
the blades 17. Alternately, primary gage pads 25 could be inclined
relative to the axis or curved in a spiral. Each primary gage pad
25 protrudes from body 13, extending the junk slots 19. Primary
gage pads 25 are dimensioned to have an outer surface 26 at the
gage or diameter of the borehole being cut. Outer surface 26
contains wear resistant surfaces, but is smooth and free of any
cutting structure. Bit body 13, along with blades 17 and gage pads
25, may be formed of a metal matrix composite or steel using a
casting or machining process.
[0026] Referring to FIG. 2, a steel threaded coupling or blank 27
is joined to an upper end of body 13. Blank 27 is bonded to body 13
during the casting process. Blank 27 protrudes from the upper end
of body 13 and has threads 29 on its exterior. An axial passage 31
extends through blank 27 and joins nozzles 23 for delivering
drilling fluid.
[0027] A shank 33 is secured to blank 27. Shank 33 is also formed
of steel, rather than of a carbide matrix. Shank 33 is a
cylindrical member that may have a length longer than the axial
dimension of body 13. Shank 33 has a threaded receptacle 35 which
engages threads 29 of blank 27. A chamfer or bevel 37 is formed on
the lower end of shank 33. Similarly, a bevel 39 is formed on the
upper end of body 13. The opposed bevels 37, 39 create a V-shaped
annular cavity. This cavity is filled with a weld material 41, the
welding permanently joining shank 33 to bit body 13. Shank 33 has
an axial passage 43 which registers with passage 31 for delivering
drilling fluid. Shank 33 has a threaded pin 45 on its upper end.
Pin 45 is dimensioned for securing to a lower end of a drill
string.
[0028] Bit assembly 11 operates in a manner that is conventional
with other steerable drag bit assemblies. It is normally secured to
a turbine or mud motor which is at the lower end of drill string.
Drilling fluid pumped down the drill string drives the mud motor,
which in turn causes rotation of bit 11. The spaced apart gage pads
25 stabilize bit 11 to condition the borehole wall, preventing
ledging and other irregularities.
[0029] The hardfacing on outer surfaces and leading and trailing
edges typically comprises a tungsten carbide material that is
welded into place. Depending on the skill of the welder, welding
such hardfacing can create imperfections and high stress zones
along the weld bead lines or in the hardfacing deposit that can
lead to the hardfacing chipping off or disengaging from the surface
it is meant to protect with its wear-resistant properties. Even for
skilled welders, the process of welding hardfacing can be time
consuming, difficult, and tedious due to the geometry of the
surfaces to which the hardfacing material is being applied. Some
surfaces, like internal surfaces that engage each other, are simply
not available for welded hardfacing.
[0030] A hardfacing metal matrix has been used on the internal
surfaces of bearings. The hardfacing metal matrix typically comes
in the form of a pliable sheet. A desired shape of the hardfacing
surface is cut out of the pliable sheet and then fusion bonded onto
the target surface, or the surface to be hardfaced. Previous
pliable hardfacing sheets comprised a metal matrix that typically
included mostly either microcrystalline tungsten carbide or
macrocrystalline tungsten carbide with lesser amounts of nickel and
chromium.
[0031] Referring to FIG. 3, a hardfacing matrix sheet 101 is shown
in its pliable state. Hardfacing matrix sheet 101 comprises a
hardfacing material matrix 103 and an adhesive surface 105 along
one surface. Adhesive surface 105 helps to hold hardfacing matrix
sheet 101 against the target surface prior to fusion bonding.
[0032] Hardfacing material matrix 103 preferably comprises
spherical sintered tungsten carbide, spherical cast tungsten
carbide, or a nanosteel composite also known as "metallic glass."
U.S. Pat. Nos. 6,689,234 and 6,767,419 provide a discussion of
metallic glass and disclose various methods of applying metallic
glass to a substrate. U.S. Pat. Nos. 6,689,234 and 6,767,419 are
incorporated herein by reference in their entireties. Matrix 103
can also comprise a combination of at least two of spherical
sintered tungsten carbide, spherical cast tungsten carbide, and
metallic glass. Microcrystalline and macrocrystalline tungsten
carbide can also be added to matrix 103 having spherical sintered
tungsten carbide, spherical cast tungsten carbide, or metallic
glass, alone or in combination. Crushed cast tungsten carbide and
crushed sintered tungsten carbide may also be added to matrix 103
having spherical sintered tungsten carbide, spherical cast tungsten
carbide, or metallic glass, alone or in combination.
[0033] Referring to FIG. 7, spherical cast tungsten carbide 117 can
comprise numerous shapes. Preferably, spherical cast tungsten
carbide 117 for use in matrix 103 will be substantially shaped like
a sphere or spherical-shaped 117a. However, spherical cast tungsten
carbide 117, but it can also be shaped like a sphere that has been
stretched from its upper and lower surfaces, or prolate-shaped
117b. Alternatively, spherical cast tungsten carbide 117 can be
shaped like a sphere that has been compressed from its upper and
lower surfaces, or oblate-shaped 117c. Spherical-, prolate-, and
oblate-shaped 117a, 117b, 117c shapes of spherical cast tungsten
carbide 117 are due to the manufacturing methods of spherical cast
tungsten carbide 117 and are useful to illustrate that the name
spherical cast tungsten carbide should not limit matrix 103 to only
spherical-shaped 117a rather than including prolate- and
oblate-shaped 117b, 117c matrixes of cast tungsten carbide.
[0034] Referring to FIG. 4, hardfacing matrix sheet 101 is cut
along pattern 107 to form a desired shape. As shown in FIG. 5,
pattern 107 preferably corresponds to a surface on bit assembly 11.
Pattern 107 shown in FIG. 4, corresponds to outer surface 57.
However, as shown in FIG. 5, various patterns 107a, 107b can be cut
from hardfacing matrix sheet 101 to correspond with desired
surfaces on bit assembly. For example, pattern 107a corresponds
with outer surface 26, and pattern 107b, corresponds with body 13
between blades 17. Moreover, hardfacing matrix sheet 101 can also
be cut with patterns to correspond to interior surfaces of bit
assembly 11.
[0035] Patterns 107a, 107b are placed on the desired surfaces of
bit assembly 11. FIG. 5, illustrates bit assembly 11 with patterns
107a, 107b being placed onto various desired surfaces. Adhesive 105
initially secures patterns 107a, 107b to the desired surfaces of
bit assembly 11. Bit assembly 11 with the secured patterns 107a,
107b attached thereto is placed into a furnace. In the preferred
embodiment, bit assembly 11 with patterns 107a, 107b is placed in
the furnace for about five to ten minutes at about 2100 degrees
Fahrenheit to fusion bond the hardfacing matrix on patterns 107a,
107b onto the desired outer surfaces of bit assembly 11. As will be
readily appreciated by those skilled in the art, the exact length
of time and exact temperature can vary depending upon the
composition of hardfacing material matrix 103 in accordance with
the variations described above herein. After fusion bonding
patterns 107a, 107b into place, hardfacing material matrix 103 can
be machined from a rough surface to a smoother surface as
desired.
[0036] Referring to FIG. 6, a microscopic representation of the
interface between hardfacing material matrix 103 on patterns 107a,
107b and the desired outer surfaces bit assembly 11 following
fusion bonding is shown. Cladding region 109 comprises hardfacing
material matrix 103 with the hardfacing material being densely
packed substantially uniformly throughout. As discussed above
herein, the particular hardfacing material can be in a nickel and
chromium matrix including spherical sintered tungsten carbide,
spherical cast tungsten carbide, or metallic glass individually, in
combination with each other, or in combination with
microcrystalline or macrocrystalline tungsten carbide. Bond region
111 is a true metallurgical bond region located between hardfacing
material matrix 103 and the desired outer surfaces of bit assembly
11 due to the fusion bonding process. Bond region 111 has high
interparticle bond strength and helps to reduce chipping, flaking
and cracking. Diffusion zone region 113 results from the fusion
bonding process. Bond region 111 comprises nickel and chromium from
patterns 107a, 107b and iron from the substrate or bit assembly 11.
Typically, the substrate or bit assembly 11 uniformly retains most
of its mechanical properties. Heat treatable region 115 includes
the remainder of the substrate of bit assembly 11. Region 115 can
be heat treated, if necessary, to restore any mechanical properties
of bit assembly 11 that may have deteriorated to the fusion bonding
process.
[0037] While the invention has been shown in only some of its
forms, it should be apparent to those skilled in the art that it is
not so limited, but is susceptible to various changes without
departing from the scope of the invention. For example, bit
assembly can also be a tri-cone bit, or cast bit.
* * * * *