U.S. patent application number 16/789835 was filed with the patent office on 2021-08-19 for method for dissolvable aluminum alloys.
This patent application is currently assigned to CNPC USA Corp.. The applicant listed for this patent is Beijing Huamei Inc., CNPC USA Corp.. Invention is credited to Timothy DUNNE, Yu LIU, Yu SANG, Yi SONG, Jianhui XU, Xiongwen YANG, Wenhan YUE.
Application Number | 20210252574 16/789835 |
Document ID | / |
Family ID | 1000004671221 |
Filed Date | 2021-08-19 |
United States Patent
Application |
20210252574 |
Kind Code |
A1 |
XU; Jianhui ; et
al. |
August 19, 2021 |
METHOD FOR DISSOLVABLE ALUMINUM ALLOYS
Abstract
The method for equal channel angular extrusion increases yield
strength and ultimate tensile strength of a dissolvable aluminum
alloy. A billet of a dissolvable aluminum alloy is wrapped with a
sheet cover so as to form a wrapped billet. The wrapped billet is
extruded through an equal channel angular extrusion die with an
extrusion angle ranging 90-135 degrees so as to form an extruded
billet. The step of extruding is at a temperature ranging 150-250
degrees C., an extrusion rate ranging 0.003-0.010 inches per
second, and a back pressure ranging 200-10000 psi. The dissolvable
aluminum alloy of the extruded billet has a yield strength and
ultimate tensile strength 50% greater than the initial yield
strength and initial ultimate tensile strength.
Inventors: |
XU; Jianhui; (Katy, TX)
; DUNNE; Timothy; (Pearland, TX) ; SANG; Yu;
(Chengdu, CN) ; SONG; Yi; (Chengdu, CN) ;
YUE; Wenhan; (Chengdu, CN) ; LIU; Yu;
(Beijing, CN) ; YANG; Xiongwen; (Beijing,
CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CNPC USA Corp.
Beijing Huamei Inc. |
Houston
Beijing |
TX |
US
CN |
|
|
Assignee: |
CNPC USA Corp.
Beijing Huamei Inc.
|
Family ID: |
1000004671221 |
Appl. No.: |
16/789835 |
Filed: |
February 13, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B21C 23/01 20130101 |
International
Class: |
B21C 23/01 20060101
B21C023/01 |
Claims
1. A method for equal channel angular extrusion, comprising the
steps of: wrapping a billet with a sheet cover so as to form a
wrapped billet, said billet being comprised of a dissolvable
aluminum alloy with an initial tensile yield strength; and
extruding said wrapped billet through an equal channel angular
extrusion die with an extrusion angle ranging 90-135 degrees so as
to form an extruded billet, wherein the step of extruding is at a
temperature ranging 150-250 degrees C., wherein the step of
extruding is at an extrusion rate ranging 0.003-0.010 inches per
second, wherein the step of extruding is at a back pressure ranging
200-10000 psi, and wherein said extruded billet has an extruded
tensile yield strength 50% greater than said initial tensile yield
strength.
2. The method of claim 1, wherein said temperature is 200 degrees
C.
3. The method of claim 1, wherein said extrusion rate is 0.005
inches per second.
4. The method of claim 1, wherein said back pressure is 8000
psi.
5. The method of claim 1, wherein said sheet cover is comprised of
one of a group consisting of brass and graphite.
6. A method for equal channel angular extrusion, comprising the
steps of: wrapping a billet with a sheet cover so as to form a
wrapped billet, said billet being comprised of a dissolvable
aluminum alloy with an initial tensile ultimate strength; and
extruding said wrapped billet through an equal channel angular
extrusion die with an extrusion angle ranging 90-135 degrees so as
to form an extruded billet, wherein the step of extruding is at a
temperature ranging 150-250 degrees C., wherein the step of
extruding is at an extrusion rate ranging 0.003-0.010 inches per
second, wherein the step of extruding is at a back pressure ranging
200-10000 psi, and wherein said extruded billet has an extruded
tensile ultimate strength 50% greater than said initial tensile
ultimate strength.
7. The method of claim 6, wherein said temperature is 200 degrees
C.
8. The method of claim 6, wherein said extrusion rate is 0.005
inches per second.
9. The method of claim 6, wherein said back pressure is 8000
psi.
10. The method of claim 6, wherein said sheet cover is comprised of
one of a group consisting of brass and graphite.
11. A method for equal channel angular extrusion, comprising the
steps of: wrapping a billet with a sheet cover so as to form a
wrapped billet, said billet being comprised of a dissolvable
aluminum alloy with an initial tensile elongation; and extruding
said wrapped billet through an equal channel angular extrusion die
with an extrusion angle ranging 90-135 degrees so as to form an
extruded billet, wherein the step of extruding is at a temperature
ranging 150-250 degrees C., wherein the step of extruding is at an
extrusion rate ranging 0.003-0.010 inches per second, wherein the
step of extruding is at a back pressure ranging 200-10000 psi, and
wherein said extruded billet has an extruded tensile elongation 50%
greater than said initial tensile elongation.
12. The method of claim 11, wherein said temperature is 200 degrees
C.
13. The method of claim 11, wherein said extrusion rate is 0.005
inches per second.
14. The method of claim 11, wherein said back pressure is 8000
psi.
15. The method of claim 11, wherein said sheet cover is comprised
of one of group consisting of brass and graphite.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
THE NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT
[0003] Not applicable.
INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC
OR AS A TEXT FILE VIA THE OFFICE ELECTRONIC FILING SYSTEM
(EFS-WEB)
[0004] Not applicable.
STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTOR OR A JOINT
INVENTOR
[0005] Not applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0006] The present invention relates to a method to process
dissolvable aluminum alloy. More particularly, the present
invention relates to a method for equal channel angular extrusion
of the dissolvable aluminum alloy. Even more particularly, the
present invention relates to a method to modify dissolvable
aluminum alloy in order to be suitable for forming downhole
components in the oil and gas industry.
2. Description of Related Art Including Information Disclosed Under
37 CFR 1.97 and 37 CFR 1.98.
[0007] Oil and gas production is commonly known to involve a
borehole through a ground formation with downhole tools, such as
plugs and sleeves positioned along and within the borehole. The
plugs close and open portions of the borehole so that a zone of
ground formation can be isolated. A sleeve opens and closes to make
the fluid connection between the borehole and the ground formation.
The downhole tools work to isolate and connect the zone for various
operations to prepare and produce the hydrocarbons from the ground
formation. When the operations are complete in the zone, components
of the downhole tool or even the entire downhole tool may require
removal. For example, a frac ball set in a plug to trigger a seal
may be removed so that the seal is removed. Alternatively, the
entire plug may be removed.
[0008] Dissolvable alloys were developed for the manufacture of
downhole tool components in the oil and gas industry. There are
mainly two types of dissolvable alloys: magnesium and aluminum
based alloys. The dissolvable aluminum alloys typically have low
ductility and low strength. The additives required for
dissolvability negatively affect desirable physical properties
needed for downhole tool components. The additives are
low-melting-point elements, such as Ga, In and Sn, which reside at
the grain boundaries or produce the secondary phase particles in
order to create micro-scale galvanic corrosion with matrix
materials. The low melting point alloys are dissolvable. However,
there are difficulties forming more complex shapes of components
with low ductility, and the components are not strong enough for
downhole conditions of higher pressure and higher temperatures. The
dissolvable aluminum alloys are typically brittle after casting due
to the existence of embrittlement elements with low melting points
such as Ga, In or Sn. Therefore, they are relatively difficult to
be processed by traditional extrusion process.
[0009] There are prior art methods for post-processing casted
dissolvable aluminum alloys. U.S. Pat. No. 8,211,248, issued on 3
Jul. 2012 to Marya, discloses heat treatment. Equal channel angular
extrusion (ECAE) is another technique from the 1970's known to
increase the strength of metals and alloys.
[0010] Due to the intrinsic brittle nature of the dissolvable
aluminum alloys, equal channel angular extrusion (ECAE) is not
inherently compatible with dissolvable aluminum alloys. FIG. 2
shows that simply being a dissolvable can result in a critical
failure. FIG. 2 shows a comparison that the regular aluminum alloy
6061 (a) can be easily processed by ECAE without issue, while using
the same ECAE conditions, a dissolvable aluminum alloy (b)
fails.
[0011] It is an object of the present invention to provide a method
for processing dissolvable aluminum alloy.
[0012] It is an object of the present invention to provide a method
to improve ductility and strength of a dissolvable aluminum
alloy.
[0013] It is an object of the present invention to provide a method
to modify a dissolvable aluminum alloy for suitability for downhole
tool components.
[0014] It is another object of the present invention to provide a
method for equal channel angular extrusion compatible with
dissolvable aluminum alloys.
[0015] These and other objectives and advantages of the present
invention will become apparent from a reading of the attached
specification.
BRIEF SUMMARY OF THE INVENTION
[0016] Embodiments of the present invention include a method for
equal channel angular extrusion. A billet of a dissolvable aluminum
alloy is wrapped with a sheet cover so as to form a wrapped billet.
The dissolvable aluminum alloy has an initial strength and an
initial tensile elongation. The method includes extruding the
wrapped billet through an equal channel angular extrusion die with
an extrusion angle ranging 90-135 degrees so as to form an extruded
billet. The step of extruding is at a temperature ranging 150-250
degrees C., an extrusion rate ranging 0.003-0.010 inches per
second, and a back pressure ranging 200-10000 psi. The dissolvable
aluminum alloy of the extruded billet has yield strength and
ultimate tensile strength 50% greater than the initial yield
strength and ultimate tensile strength.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0017] FIG. 1 is a schematic view of an equal channel angular
extrusion method.
[0018] FIG. 2 are photos (a) and (b) of a regular aluminum alloy
and a dissolvable aluminum alloy after an equal channel angular
extrusion in the same conditions.
[0019] FIG. 3 are photos (a) and (b) of a dissolvable aluminum
alloy after an equal channel angular extrusion in different
temperature conditions.
[0020] FIG. 4 are photos (a) and (b) of a dissolvable aluminum
alloy after an equal channel angular extrusion at different
extrusion rates.
[0021] FIG. 5 are photos (a), (b), and (c) of a dissolvable
aluminum alloy after an equal channel angular extrusion at
different back pressures.
[0022] FIG. 6 are photos (a) and (b) of a dissolvable aluminum
alloy after an equal channel angular extrusion with and without
wrapping materials.
[0023] FIG. 7 are photos (AA), (AC), (AG), and (AH) of four
dissolvable aluminum alloys after an equal channel angular
extrusion within the critical range of conditions.
[0024] FIG. 8 are photos (a) and (b) of a dissolvable aluminum
alloy before and after an equal channel angular extrusion within
the critical range of conditions.
[0025] FIG. 9 is a graph illustration of tensile tests of
dissolvable aluminum alloys before and after an equal channel
angular extrusion within the critical range of conditions.
DETAILED DESCRIPTION OF THE INVENTION
[0026] FIGS. 1-9 show the embodiments of the present invention as a
method for equal channel angular extrusion of a dissolvable
aluminum alloy with improved yield strength and ultimate tensile
strength. There is an incompatibility of dissolvable aluminum alloy
with equal channel angular extrusion (ECAE) methods due to the very
nature of the low melt elements used for the dissolvability. As a
material composition for downhole tool components, the
dissolvability cannot be eliminated. The dissolvability is the
feature that is required of particular downhole tool components.
FIG. 2 shows the critical limitation of the dissolvability. The
regular aluminum alloy is easily processed without issue, while the
dissolvable aluminum alloy is a complete failure. The dissolvable
aluminum alloy can be rendered non-functional by the ECAE method in
FIG. 2.
[0027] FIG. 1 shows the method for equal channel angular extrusion.
A billet 10 is wrapped with a sheet cover 12 so as to form a
wrapped billet. The billet 10 is comprised of a dissolvable
aluminum alloy with an initial tensile yield strength, an initial
tensile ultimate strength, and an initial tensile elongation. The
sheet cover 12 can be comprised of brass or graphite. The method
includes extruding the wrapped billet through an equal channel
angular extrusion die 20 with an extrusion angle 22 ranging 90-135
degrees so as to form an extruded billet. The temperature of the
method can be controlled. FIG. 1 shows a pressing plunger 30 to set
an extrusion rate by pressure P and a back plunger 32 to set a back
pressure PB. Temperature, extrusion rate, back pressure, and
wrapping are ECAE conditions that can affect the extruded aluminum
alloy in the ECAE method of the present invention
TABLE-US-00001 TABLE 1 results for temperature, extrusion rate,
back pressure, and wrapping Back Temperature Extrusion Rate
Pressure Critical FIG. (degrees C.) (inches/sec) (psi) Wrapping
Fail 2 (a), 4(a) 250 0.01 200 YES YES 3 (a) 100 0.005 200 YES YES 3
(b), 4 200 0.005 200 YES NO (b), 5 (a) 5 (b) 200 0.005 4000 YES NO
5 (c) 200 0.005 8000 YES NO 6 (a) 330 0.005 0 NO YES 6 (b) 330
0.005 4000 YES NO 7-AA 200 0.005 8000 YES NO 7-AC 200 0.005 8000
YES NO 7-AG 200 0.005 8000 YES NO 7-AH 200 0.005 8000 YES NO
[0028] There is a critical range of the temperature. FIG. 2-6 show
that temperatures both above and below 250 degrees can avoid
fracturing of the extruded dissolvable aluminum alloy by an ECAE
method. There is no teaching either way that higher or lower
temperatures are better for dissolvable aluminum alloys.
Furthermore, FIG. 2 shows that a lower temperature can also be too
low. Additionally, a higher temperature can also be too high. A
trial at 330 degrees C. avoided fracturing, but the dissolvable
aluminum alloy over 400 degrees C. is already known to be
fracturing and non-functional based on known heat treatments at 400
degrees C. There are critical ranges for temperature above and
below 250 degrees C., depending on other ECAE conditions.
[0029] There is a critical range of the extrusion rate. FIGS. 2-4
show that slower extrusion rates can avoid fracturing of the
extruded dissolvable aluminum alloy by an ECAE method. Even at
extrusion rates slower than 0.01 inches/sec, there can still be
failure of the extruded dissolvable aluminum alloy. FIGS. 3 and 4
show that an extrusion rate lower than 0.01 inches/sec can avoid
fracturing, depending on temperature. There is no teaching that
increasing extrusion rate above 0.01 inches per second can avoid
fracturing, but it is known that increasing extrusion rate is more
likely to fail since the billet encounters less strain. When there
is already failure at 0.01 inches/sec, the teaching is to go
slower. However, the present invention shows that going slower than
0.01 inches/sec is not a guarantee to eventually avoid fracturing
either. There is still a critical range for extrusion rate in FIGS.
2-4.
[0030] Back pressure can also be a critical ECAE condition. Table 1
shows failures between 0-200 psi, while FIG. 5 shows that the back
pressure from 200-8000 psi can avoid fracturing. A minimal back
pressure at 200 psi appears to be a critical pressure. Higher back
pressures were also able to yield viable extruded dissolvable
aluminum alloys after the ECAE process. The back pressure confines
the material in the extrusion chamber in extrusion direction during
the ECAP process, so that the material in the extrusion process
will keep the integrity from all directions.
[0031] FIG. 6 shows the benefit of wrapping to improve the ECAE
process. There can be failures with or without wrapping.
Embodiments of the present invention include the sheet cover of the
wrapping material as brass, graphite or pure aluminum, which can
act as a solid lubrication for the billet 10 of dissolvable
aluminum alloy. The results of Table 1 indicate that wrapping is a
critical ECAE condition with the extruded dissolvable aluminum
alloy only avoiding fractures when wrapped.
[0032] Table 1 identifies the critical ranges as now claimed. The
temperature has a range of 150-250 degrees C. with an extrusion
rate range of 0.003-0.010 inches per second and a back pressure
range of 200-10000 psi. Additionally, these conditions require
wrapping. The present invention indicates the critical ranges
interacting to avoid fractures in the extruded dissolvable aluminum
alloy.
[0033] Beyond achieving a functional extruded dissolvable aluminum
alloy, the method of the present invention further includes
unexpected performance. Simply avoiding complete structural failure
is important for components of downhole tools, but there is a
further benefit beyond forming an extruded dissolvable aluminum
alloy.
TABLE-US-00002 TABLE 2 results of FIG. 7 for increased strengths
and sometimes elongation. Tensile Tensile Tensile Tensile Ultimate
Ultimate Tensile Tensile Yield Strength Yield Strength Strength
Strength Elongation Elongation BEFORE AFTER BEFORE AFTER BEFORE
AFTER Sample (MPa) (MPa) (MPa) (MPa) (%) (%) AA 137 275 190 325 3.3
8.7 AC 122 265 190 290 4.7 2.9 AG 153 273 187 320 1.4 2.1 AH 125
252 225 290 7.0 6.5
[0034] After identifying the ECAE conditions of the present
invention, dissolvable aluminum materials were processed
successfully, as shown in FIG. 7 and FIG. 8. The parts were
processed without fractures that would render the extruded
dissolvable aluminum alloy unuseable. FIG. 8 shows an example of
microstructural evolution during the ECAE process with 8(a) showing
a view before the ECAE process and 8(b) showing a view after the
ECAE process. In the ECAE processed materials, there is less
micro-porosity, and there is more even distribution of secondary
phase particles. Micro-porosity and even distribution of secondary
phase particles can contribute to the improvement of tensile
mechanical properties. FIG. 9 shows the increased yield strength
and ultimate tensile strength. Table 2 summarizes the improvement
ranging 60-100% to support the unexpected 50% increase in yield
strength and ultimate tensile strength of extruded dissolvable
aluminum alloy.
[0035] In the present invention, just to achieve extruded
dissolvable aluminum alloy that does not fracture is surpassed by
the additional findings of Table 2. There are actual improvements
to mechanical properties beyond just being able to form components
of downhole tools without fractures.
[0036] The present invention provides a method for processing
dissolvable aluminum alloy. After being cast, the dissolvable
aluminum alloy must be formed into shapes that correspond to
components of downhole tools. Being brittle makes the formation of
parts difficult. Once formed, the component must have the necessary
strength for downhole conditions, while remaining dissolvable. The
present invention improves the strengths of a dissolvable aluminum
alloy in a post processing treatment of dissolvable aluminum alloy.
Previously unusable or at least time consuming and expensive
processing for downhole tool components can be avoided. The method
for an equal channel angular extrusion has been modified to be
compatible with dissolvable aluminum alloys. Regular alloys do not
require such modifications, and there are critical ranges to avoid
fracturing and failure of the extruded material. The present
invention identifies these critical ranges to avoid failure and
further achieves an unexpected improvement in strengths.
[0037] The foregoing disclosure and description of the invention is
illustrative and explanatory thereof. Various changes in the
details of the illustrated structures, construction and method can
be made without departing from the true spirit of the
invention.
* * * * *