U.S. patent application number 09/758896 was filed with the patent office on 2001-06-07 for composition for binder material particularly for drill bit bodies.
Invention is credited to Kembaiyan, Kuttaripalayam T., Oldham, Thomas W..
Application Number | 20010002557 09/758896 |
Document ID | / |
Family ID | 23470070 |
Filed Date | 2001-06-07 |
United States Patent
Application |
20010002557 |
Kind Code |
A1 |
Kembaiyan, Kuttaripalayam T. ;
et al. |
June 7, 2001 |
Composition for binder material particularly for drill bit
bodies
Abstract
A composition for drill bit bodies and a method for making drill
bits from the composition are disclosed. The composition includes
powdered tungsten carbide, and binder metal consisting of a
composition by weight of manganese in a range of about zero to 25
percent, nickel in a range of about zero to 15 percent, zinc in a
range of about 3 to 20 percent, tin in a range of more than 1
percent to about 10 percent, and copper making up the remainder by
weight of the composition. In one embodiment, the composition
includes about 6 to 7 percent tin therein. The composition is
heated to at least the infiltration temperature in a mold for form
a drill bit body.
Inventors: |
Kembaiyan, Kuttaripalayam T.;
(The Woodlands, TX) ; Oldham, Thomas W.; (The
Woodlands, TX) |
Correspondence
Address: |
ROSENTHAL & OSHA L.L.P.
Suite 4550
700 Louisiana
Houston
TX
77002
US
|
Family ID: |
23470070 |
Appl. No.: |
09/758896 |
Filed: |
January 11, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09758896 |
Jan 11, 2001 |
|
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|
09372896 |
Aug 12, 1999 |
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Current U.S.
Class: |
75/240 |
Current CPC
Class: |
E21B 10/00 20130101;
B22F 2005/001 20130101; B22F 7/06 20130101; C22C 29/067
20130101 |
Class at
Publication: |
75/240 |
International
Class: |
C22C 029/08 |
Claims
What is claimed is:
1. A drill bit, comprising: a composite structural body comprising
powdered tungsten carbide and binder alloy, said binder alloy
comprising a composition by weight of manganese in a range of about
zero to 25 percent, nickel in a range of about zero to 15 percent,
zinc in a range of about 3 to 20 percent, tin in a range of more
than 1 percent to about 10 percent, and copper making up the
remainder by weight of said composition, said binder alloy
infiltrated through said tungsten carbide; and cutters bonded to
said composite structural body.
2. The drill bit as defined in claim 1 wherein said tin comprises
about 6 to 7 percent of said alloy composition.
3. The drill bit as defined in claim 1 wherein said copper
comprises about 57 percent of said alloy composition, said
manganese comprises about 23 percent of said alloy composition,
said nickel comprises about 10 percent of said alloy composition,
said zinc comprises about 4 percent of said alloy composition, and
said tin comprises about 6 percent of said alloy composition.
4. The drill bit as defined in claim 1 wherein said cutters
comprise polycrystalline diamond compact inserts bonded to said
composite structural body.
5. The drill bit as defined in claim 1 wherein said cutters
comprise diamonds formed into blades in said composite structural
metal body.
6. A method for forming a drill bit body, comprising: inserting
into a mold a mixture comprising powdered tungsten carbide and a
binder alloy consisting of a composition by weight of manganese in
a range of about zero to 25 percent, nickel in a range of about
zero to 15 percent, zinc in a range of about 3 to 20 percent, tin
in a range of more than 1 percent to about 10 percent, and copper
making up the remainder by weight of the alloy composition; and
heating the mixture to at least an infiltration temperature of the
binder alloy to bind the alloy to the powdered tungsten
carbide.
7. The method as defined in claim 6 wherein said tin comprises
about 6 to 7 percent of said binder alloy.
8. The method as defined in claim 6 wherein said copper comprises
about 57 percent of said composition, said manganese comprises
about 23 percent of said composition, said nickel comprises about
10 percent of said composition, said zinc comprises about 4 percent
of said composition, and said tin comprises about 6 percent of said
composition.
9. The method as defined in claim 6 further comprising inserting
diamonds into said mold prior to said heating, so that an
impregnated diamond drill bit is formed thereby.
10. The method as defined in claim 6 further comprising bonding
polycrystalline diamond compact inserts to said drill bit body to
form a drill bit thereby.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a division of Ser. No. 09/372,896, filed on Aug. 12,
1999.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates generally to the field of metal alloys
used for various types of housings. More specifically, the
invention relates to compositions of binder material used to bind
metallic powders into solid housings or bodies for such purposes as
petroleum wellbore drilling bits.
[0004] 2. Description of the Related Art
[0005] Petroleum wellbore drilling bits include various types that
contain natural or synthetic diamonds, polycrystalline diamond
compact (PDC) inserts, or combinations of these elements to drill
through earth formations. The diamonds and/or PDC inserts are
bonded to a bit housing or "body". The bit body is typically formed
from powdered tungsten carbide ("matrix") which is bonded into a
solid form by fusing a binder alloy with the tungsten carbide. The
binder alloy is typically in the form of cubes, but it can also be
in powdered form. To form the body, the powdered tungsten carbide
is placed in a mold of suitable shape. The binder alloy, if
provided in cube form is typically placed on top of the tungsten
carbide. The binder alloy and tungsten carbide are then heated in a
furnace to a flow or infiltration temperature of the binder alloy
so that the binder alloy can bond to the grains of tungsten
carbide. Infiltration occurs when the molten binder alloy flows
through the spaces between the tungsten carbide grains by means of
capillary action. When cooled, the tungsten carbide matrix and the
binder alloy form a hard, durable, strong framework to which
diamonds and/or PDC inserts are bonded or otherwise attached. Lack
of complete infiltration will result in a defective bit body.
Typically, natural or synthetic diamonds are inserted into the mold
prior to heating the matrix/binder mixture, while PDC inserts can
be brazed to the finished bit body.
[0006] The chemical compositions of the matrix and binder alloy are
selected to optimize a number of different properties of the
finished bit body. These properties include transverse rupture
strength (TRS), toughness (resistance to impact-type fracture),
wear resistance (including resistance to erosion from rapidly
flowing drilling fluid and abrasion from rock formations), steel
bond strength between the matrix and steel reinforcing elements,
and strength of the bond (braze strength) between the finished body
material and the diamonds and/or inserts.
[0007] One particular property of the binder alloy which is of
substantial importance is its flow or infiltration temperature,
that is, the temperature at which molten binder alloy will flow
around all the matrix grains and attach to the matrix grains. The
flow temperature is particularly important to the manufacture of
diamond bits, in which case the diamonds are inserted into the mold
prior to heating. The chemical stability of the diamonds is
inversely related to the product of the duration of heating of the
diamonds and the temperature to which the diamonds are heated as
the bit body is formed. Generally speaking, all other properties of
the bit body being equal, it is desirable to heat the mixture to
the lowest possible temperature for the shortest possible time to
minimize thermal degradation of the diamonds. While binder alloys
which have low flow temperature are known in the art, these binder
alloys typically do not provide the finished bit body with
acceptable properties.
[0008] Many different binder alloys are known in the art. The
mixtures most commonly used for commercial purposes, including
diamond drill bit making, are described in a publication entitled,
Matrix Powders for Diamond Tools, Kennametal Inc., Latrobe, Pa.
(1989). A more commonly used binder alloy has a composition by
weight of about 52 percent copper, 15 percent nickel, 23 percent
manganese, and 9 percent zinc. This alloy has a melting temperature
of about 1800 degrees F (968 degrees C) and a flow (infiltration)
temperature of about 2150 degrees F (1162 degrees C). Other prior
art alloys use combinations of copper, nickel and zinc, or copper,
nickel and up to about 1 percent tin by weight.
[0009] Tin is known in the art to reduce the melting and flowing
temperature of the binder alloy. However, it was believed by those
skilled in the art that tin concentrations exceeding about 1
percent by weight in the binder alloy would adversely affect the
other properties of the finished bit body material, particularly
the toughness, although transverse rupture strength and braze
strength can also be adversely affected.
[0010] It is desirable to have a binder alloy having as low as
possible a flowing temperature consistent with maintaining the
toughness, transverse rupture strength and braze strength of the
finished body material.
SUMMARY OF THE INVENTION
[0011] One aspect of the invention is a matrix material used, for
example, in drill bit bodies. The matrix material includes powdered
tungsten carbide, and binder alloy consisting of a composition by
weight of manganese in a range of about zero to 25 percent, nickel
in a range of about zero to 15 percent, zinc in a range of about 3
to 20 percent, tin in a range of more than 1 percent to about 10
percent, and copper making up the remainder by weight of the alloy
composition. In one embodiment, the alloy includes about 6 to 7
percent tin by weight.
[0012] Another aspect of the invention is a method for forming
drill bit bodies. The method includes inserting into a mold a
mixture including powdered tungsten carbide and a binder alloy
consisting of a composition, by weight, of manganese in a range of
about zero to 25 percent, nickel in a range of about zero to 15
percent, zinc in a range of about 3 to 20 percent, tin in a range
of more than 1 percent to about 10 percent, and copper making up
the remainder by weight of the alloy. The matrix material is heated
to the flow temperature of the binder alloy to infiltrate through
the powdered tungsten carbide. In one embodiment, the binder alloy
includes about 6 to 7 percent tin by weight.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows an end view of a drill bit formed from a body
material having binder according to the invention.
[0014] FIG. 2 shows a side view of the drill bit shown in FIG.
1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] FIG. 1 shows an end view of a so-called "impregnated
diamond" drill bit 10. The drill bit 10 is formed into a generally
cylindrically shaped body 11 which includes circumferentially
spaced apart blades 12. The blades 12 include natural or synthetic
diamonds (not shown in FIG. 1) embedded in the outer surfaces
thereof. As is well known in the art, the drill bit 10 is coupled
to a rotary power source such as a drill pipe (not shown) or an
hydraulic motor (not shown) to rotate the drill bit 10 as it is
axially pressed against earth formations to drill the earth
formations. Such diamonds are one classification of so-called
"cutters" which deform or scrape the earth formations to drill
them. Another well known form of such cutters is polycrystalline
diamond compact (PDC) inserts which are typically brazed to the
body 11 after it is formed.
[0016] A side view of the drill bit 10 is shown in FIG. 2. The
drill bit 10 can include, at the end of the body 11 opposite to the
end shown in FIG. 1, a threaded coupling 16 for attachment to the
drill pipe or hydraulic motor, and may include gauge pads 14 or the
like to maintain the diameter of the hole drilled by the drill bit
10.
[0017] The invention concerns the composition of the material from
which the body 11 is formed, and more specifically, concerns the
composition of a binder alloy used to bond together grains of
powdered metal to form the body 11.
[0018] As described in the Background section herein, the body 11
is typically formed by infiltrating powdered tungsten carbide with
a binder alloy. The tungsten carbide and binder alloy are placed in
a mold (not shown) of suitable shape, wherein the part of the mold
having forms for the blades 12 will have diamonds mixed with the
powdered tungsten carbide to form one of the so-called diamond
impregnated drill bits. The mold having diamonds, carbide and
binder alloy therein is then heated in a furnace to the flow or
infiltration temperature of the binder alloy for a predetermined
time to enable the molten binder alloy to flow around the grains of
the tungsten carbide.
[0019] It has been determined that binder alloy compositions to be
described below provide the finished body 11 with suitable
combinations of transverse rupture strength (TRS), toughness, braze
strength and wear resistance. A preferred binder alloy composition
includes by weight about 57 percent copper, 10 percent nickel, 23
percent manganese, 4 percent zinc and 6 percent tin. This
composition for the binder alloy has a melting temperature of about
1635 degrees F (876 degrees C) and a flow or infiltration
temperature of about 1850 degrees F (996 degrees C).
[0020] Other compositions of binder alloy according to the
invention can have, by weight, nickel in the range of about zero to
15 percent; manganese in the range of about zero to 25 percent;
zinc in the range of about 3 to 20 percent, and tin more than 1
percent up to about 10 percent. The remainder of any such
composition is copper. The preferred amount of tin in the binder
alloy is about 6 to 7 percent. Although nickel and manganese can be
excluded from the binder alloy entirely, is should be noted that
nickel helps the mixture "wet" the tungsten carbide grains, and
increases the strength of the finished bit body. Manganese, when
included in the recommended weight fraction range of the binder
alloy composition, also helps lower the melting temperature of the
binder alloy. While it is known that tin will lower the melting and
flowing temperature of the binder alloy, too much tin in the binder
alloy will result in the finished body 11 having too low a
toughness, that is, it will be brittle. Including tin in the
recommended weight fraction in the binder alloy composition results
in a substantial decrease in the infiltration temperature of the
binder alloy, as well as improved wettability of the binder alloy,
particularly of the diamonds. The other properties of the finished
bit body material will be maintained with commercially acceptable
limits, however.
[0021] While the example embodiment described herein is directed to
an impregnated diamond bit, it should be clearly understood that
PDC insert bits can have the bodies thereof formed from a composite
material having substantially the same composition as described
herein for diamond impregnated bits. It has been determined that
the material described herein is entirely suitable for PDC insert
bit bodies, and has the advantage of being formed at a lower
temperature than materials of the prior art. Lowering the
temperature can reduce energy costs of manufacture and can reduce
deterioration of insulation on the furnace walls, and the furnace
heating elements. Lowering the infiltration temperature also
provide the advantage of minimizing the degradation of drill bit
components such as reinforcement steel blanks and the matrix
powders which can oxidize at higher furnace temperatures, thereby
softening and losing strength.
[0022] Those skilled in the art will appreciate that other
embodiments of the invention can be devised which do not depart
from the spirit of the invention as disclosed herein. Accordingly,
the scope of the invention should be limited only by the attached
claims.
* * * * *