U.S. patent application number 15/583703 was filed with the patent office on 2017-08-17 for feedstock for metal foil product and method of making thereof.
The applicant listed for this patent is Arconic Inc.. Invention is credited to John W. Collins, III, David W. Timmons, David Tomes, Ali Unal, Gavin F. Wyatt-Mair.
Application Number | 20170233856 15/583703 |
Document ID | / |
Family ID | 41404462 |
Filed Date | 2017-08-17 |
United States Patent
Application |
20170233856 |
Kind Code |
A1 |
Tomes; David ; et
al. |
August 17, 2017 |
FEEDSTOCK FOR METAL FOIL PRODUCT AND METHOD OF MAKING THEREOF
Abstract
The present invention discloses a product comprising a 1xxx,
3xxx and 8xxx series aluminum alloy made by a non-ingot casting
process, where the aluminum alloy has a thickness of about 5
micrometers to about 150 micrometers for a foil product. The
product has an O-temper tensile strength, O-temper elongation, and
O-temper Mullen pressure that are at least 10% greater compared to
the average values of the same alloy in O-temper cast using a slab
or roll-casting process. The product is substantially free of
pinholes caused by centerline segregation of intermetallic
particles. In another embodiment, the present invention discloses a
8111 or 8921 aluminum alloy made by a non-ingot casting process,
where the aluminum alloy has a thickness of about 5 micrometers to
about 150 micrometers for a foil product. The product has an
O-temper tensile strength, O-temper elongation, and O-temper Mullen
pressure that are at least 10% greater than the average values of
the same alloy in O-temper made from feedstock prepared by slab or
roll casting processes. The product is substantially free of
pinholes caused by centerline segregation of intermetallic
particles.
Inventors: |
Tomes; David; (San Antonio,
TX) ; Timmons; David W.; (Helotes, TX) ;
Wyatt-Mair; Gavin F.; (Lafayette, CA) ; Unal;
Ali; (Export, PA) ; Collins, III; John W.;
(Austin, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Arconic Inc. |
Pittsburgh |
PA |
US |
|
|
Family ID: |
41404462 |
Appl. No.: |
15/583703 |
Filed: |
May 1, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12246937 |
Oct 7, 2008 |
|
|
|
15583703 |
|
|
|
|
Current U.S.
Class: |
428/606 |
Current CPC
Class: |
C22C 21/10 20130101;
B22D 11/003 20130101; C22C 21/16 20130101; C22C 21/06 20130101;
C22F 1/04 20130101; C22F 1/053 20130101; C22C 21/18 20130101; C22C
21/02 20130101; B22D 11/0622 20130101; C22C 21/00 20130101; B22D
11/1206 20130101; C22F 1/043 20130101; C22C 21/14 20130101; C22F
1/057 20130101; B22D 11/001 20130101; C22C 21/08 20130101; C22F
1/047 20130101 |
International
Class: |
C22F 1/043 20060101
C22F001/043; C22C 21/02 20060101 C22C021/02; C22C 21/18 20060101
C22C021/18; C22C 21/16 20060101 C22C021/16; C22F 1/047 20060101
C22F001/047; C22C 21/10 20060101 C22C021/10; C22C 21/08 20060101
C22C021/08; C22F 1/057 20060101 C22F001/057; C22F 1/053 20060101
C22F001/053; B22D 11/00 20060101 B22D011/00; C22C 21/14 20060101
C22C021/14 |
Claims
1. A product comprising: a 1xxx, 3xxx or 8xxx series aluminum
alloy, wherein the aluminum alloy has a thickness of about 5
micrometers to about 150 micrometers for a foil product, wherein
the aluminum alloy is substantially free of beta intermetallic
phase particles; wherein the aluminum alloy is substantially free
of alpha prime intermetallic phase particles; and wherein a yield
strength of the product is 45 MPa to 120 MPa.
2. A product comprising: an 8111 aluminum alloy, wherein the
aluminum alloy has a thickness of about 5 micrometers to about 150
micrometers for a foil product, wherein the aluminum alloy is
substantially free of beta intermetallic phase particles; wherein
the aluminum alloy is substantially free of alpha prime
intermetallic phase particles; and wherein a yield strength of the
product is 45 MPa to 120 MPa.
3. A product comprising: an 8921 aluminum alloy made by a non-ingot
casting process without homogenization and without intermediate
anneal, wherein the aluminum alloy has a thickness of about 5
micrometers to about 150 micrometers for a foil product, and
wherein the aluminum alloy is free of beta intermetallic phase
particles.
4. The product of claim 1, wherein the aluminum alloy consists
essentially of a 1xxx series aluminum alloy.
5. The product of claim 1, wherein the aluminum alloy consists
essentially of a 3xxx series aluminum alloy.
6. The product of claim 1, wherein the aluminum alloy consists
essentially of an 8xxx series aluminum alloy.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/246,937, filed on Oct. 7, 2008, entitled "A
FEEDSTOCK FOR METAL FOIL PRODUCT AND METHOD OF MAKING THEREOF",
which is incorporated herein by reference in its entirety for all
purposes.
BACKGROUND OF THE INVENTION
[0002] A feedstock is a material that needs to undergo further
processing before it becomes a final product. In one embodiment,
the end use application for these feedstock covers various products
such as packaging needs i.e. household foils. In another
embodiment, the aluminum foil products made from the feedstock
disclosed has improved surface characteristics and mechanical
properties such as high burst pressure, high tensile strength, high
yield strength and higher percentage elongation at thin gauges.
SUMMARY OF THE INVENTION
[0003] In one embodiment, the present invention provides a
feedstock product. In another embodiment, the product comprises a
1xxx, 3xxx and 8xxx series aluminum alloy made by a non-ingot
casting process where the aluminum alloy has a thickness of about 5
micrometers to about 150 micrometers for a foil product. The
product has an O-temper tensile strength that is at least 10%
greater compared to the average values of the same alloy in
O-temper cast using a slab or roll-casting process. The product has
an O-temper elongation that is at least 10% greater compared to the
average values of the same alloy in O-temper cast using a slab or
roll-casting process. The product has an O-temper Mullen pressure
that is at least 10% greater compared to the average values of the
same alloy in O-temper cast using a slab or roll-casting process.
The product is substantially free of pinholes caused by centerline
segregation of intermetallic particles.
[0004] In one embodiment, the product comprises an 8111 aluminum
alloy made by a non-ingot casting process where the aluminum alloy
has a thickness of about 5 micrometers to about 150 micrometers for
a foil product. The product has a tensile strength in O-temper that
is at least 10% greater than the average values of standard 8111
alloy in O-temper. The product has an elongation in O-temper that
is at least 10% greater than the average values of standard 8111
alloy in O-temper. The product has a Mullen pressure in O-temper
that is at least 10% greater than the average values of standard
8111 alloy in O-temper. The product is substantially free of
pinholes caused by centerline segregation of intermetallic
particles.
[0005] In another embodiment, the product comprises an 8921
aluminum alloy made by a non-ingot casting process where the
aluminum alloy has a thickness of about 5 micrometers to about 150
micrometers for a foil product. The product has a tensile strength
in O-temper that is at least 10% greater than the average values of
standard 8921 alloy in O-temper. The product has an elongation in
O-temper that is at least 10% greater than the average values of
standard 8921 alloy in O-temper. The product has a Mullen pressure
in O-temper that is at least 10% greater than the average values of
standard 8921 alloy in O-temper. The product is substantially free
of pinholes caused by centerline segregation of intermetallic
particles.
[0006] Accordingly, it is one embodiment of the invention to
provide a feedstock with improved properties.
[0007] These and other further embodiments of the invention will
become more apparent through the following description and
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] For a fuller understanding of the invention, reference is
made to the following description and the accompanying drawing(s),
in which:
[0009] FIG. 1 is a flow chart showing the existing method of making
foil and fin from roll cast feedstock;
[0010] FIG. 2 is a flow chart showing one embodiment of the method
of making foil in accordance with the present invention;
[0011] FIG. 3 is three layered casting strip of one embodiment of
the present invention; and
[0012] FIG. 4 is a photomicrograph at 100 times magnification of
the transverse section of the as cast strip alloy 8921 of one
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] The following are the definitions of the terms used in this
application. As used herein, the term "feedstock" means that the
material that needs to undergo further processing before it becomes
a final product such as a household foil.
[0014] As used herein, the term "aluminum alloy" means an aluminum
metal with other elements. Elements may include copper, iron,
magnesium, nickel, silicon, zinc, chromium, manganese, titanium,
vanadium, zirconium, tin, and/or scandium. Elements are added to
influence physical properties of the aluminum alloy and performance
characteristics.
[0015] As used herein, the term "centerline segregation" means
aligned intermetallic particles in the center plane of strip made
by conventional roll casters. It can lead to tearing of the sheet
during rolling and results in poor mechanical properties in the
final product.
[0016] As used herein, the term "refined microstructures" means
microstructures with fine grain size and fine constituents.
[0017] As used herein, the term "beta intermetallic phase
particles" means rod like particles of Al.sub.9FeSi composition.
These are brittle particles that break up during rolling and result
in inferior mechanical properties in the final product. Their
detrimental effects are eliminated by homogenization treatments
that convert the beta phase to the more ductile alpha phase.
[0018] As used herein, the term "in-line" means without
intermediate coiling and uncoiling.
[0019] As used herein, the term "grain refiner" means a chemical
compound such as TiB.sub.2, TiC or AlTi that helps create a finer
grain structure in the cast metal.
[0020] As used herein, the term "Mullen burst pressure" means
pressure at which a sheet tears. It measures resistance to
tearing.
[0021] As used herein, the term "substantially" means to a great
extent or degree.
[0022] As used herein, the term "non-ingot casting process" means
any casting process that does not produce an ingot.
[0023] As used herein, the term "slab process" means a process that
casts a slab between about 0.25 inches and about 8 inches in
thickness.
[0024] As used herein, the term "roll-casting process" means
casting a strip of thickness of about 0.25 inches to about 0.5
inches at speeds of less than 10 feet per minute using convention
roll casters at high roll separating forces.
[0025] As used herein, the term "pinholes" means a small hole in a
metal sheet or foil as measured in a light box.
[0026] As used herein, the term "hot rolling" means rolling of
aluminum metal at an entry temperature above about 700.degree.
F.
[0027] As used herein, the term "warm rolling" means rolling of
aluminum metal at an entry temperature range of about 350.degree.
F. to about 700.degree. F.
[0028] As used herein, the term "cold rolling" means rolling of
aluminum metal at a entry temperature below about 350.degree.
F.
[0029] In one embodiment, the present invention discloses a
feedstock produced using a method that includes producing a casting
strip of a thickness of less than about 6 mm from an aluminum
alloy, hot rolling the casting strip in-line to a thickness of no
greater than about 1 mm, and coiling the resultant strip to produce
the feedstock product for a metal foil, where the cast strip is
substantially free of beta intermetallic phase particles.
[0030] In another embodiment, the feedstock is further processed to
provide a metal foil with improved mechanical properties and
surface characteristics.
[0031] In another embodiment, the feedstock product is then further
processed by un-coiling the strip, cold rolling the feedstock strip
to a required product thickness, and partially or fully annealing
the final-gauge strip to produce a metal foil.
[0032] FIG. 1 shows a flow chart outlining the principal steps for
the conventional process of making foil and fin products from roll
cast feedstock. In the initial step 10, the aluminum alloy is roll
cast to a thickness between about 6 mm and about 10 mm. The
aluminum alloy casting strip is then hot/warm coiled in-line 20 and
then optionally separately homogenized at around 430.degree. C. to
about 530.degree. C. In the next step 40, the homogenized coil is
then un-coiled so that the aluminum alloy casting strip may be cold
rolled to an intermediate gauge in step 50. The intermediate gauge
strip is then intermediately annealed at 450.degree. C. in step 60
and cold rolled to the final gauge of the foil. In the final step
80, the aluminum alloy casting strip is optionally either partially
or fully annealed depending on the physical properties needed for
the product.
[0033] In one embodiment, FIG. 2 shows a flow chart outlining the
principal steps of the present invention. The present invention
eliminates the lengthy and expensive homogenization and/or
intermediate anneal steps normally associated with the current
methods of roll cast or ingot feedstock and eliminates one or more
cold rolling passes. Here, the feedstock strip cast of thickness of
less than about 6 mm material is produced at high speeds in the
first step 100. The aluminum alloy material is then hot rolled
in-line in the second step 200 to a thickness of at most about 1 mm
at about 720.degree. F. The feedstock material is then hot/warm
coiled in-line in the third step 300. This material is an
embodiment of the feedstock of the present invention, provided for
further off-line processing into a finished product. In such an
off-line operation, the coil is then un-coiled in step 400 prior to
being cold rolled in the fifth step 500 to finish gauge, which is
the required product thickness. The finished gauge product may
optionally be subjected to a partial or full anneal treatment in
the sixth step 600 depending on the application, or supplied in
as-rolled condition
[0034] In the initial step, a strip of less than about 6 mm in
thickness is cast. In one embodiment, a method of making the
casting strip of a thickness of less than about 6 mm from an
aluminum alloy is done by continuously casting the aluminum alloy.
This includes delivering molten aluminum alloy juxtaposed and in
communication with a pair of water-cooled rolls arranged in a
generally horizontal plane. This casting is done at high speeds,
such as about 200 fpm (62 m/min). Molten aluminum alloy from a
reservoir is advanced towards a nip between the rolls. Outer layers
of solid aluminum alloy forms on each of the rolls, and a
semi-solid aluminum layer is produced in the center between the
solid layers. The semi-solid layer includes a molten component and
a solid component of broken dendritic arms detached from the
solidification front. The solid outer layers and the solid
component of the semi-solid aluminum alloy pass through the nip
such that a strip of solid aluminum alloy exits the nip. The strip
exiting the nip includes a solid central layer sandwiched between
the outer conforming layers of aluminum alloy.
[0035] In another embodiment, a method of making the casting strip
of a thickness of less than about 6 mm from an aluminum alloy is by
in one, continuous in-line sequence that includes the following
steps: (a) a hot aluminum feedstock is hot rolled to reduce its
thickness; (b) the hot reduced feedstock is thereafter annealed
in-line without substantial intermediate cooling; (c) the annealed
feedstock is thereafter immediately and rapidly quenched to a
temperature suitable for cold rolling; and (d) the quenched
feedstock is subjected to cold rolling to produce sheet having
desired thickness and metallurgical properties.
[0036] The resulting casting strip produced has a refined
microstructure and surprisingly, is substantially free of beta
intermetallic phase particles. This results in superior quality
foil products.
[0037] Types of aluminum alloys that may be used in the present
invention include, but are not limited to, 1XXX, 3XXX, and 8XXX
aluminum alloys (Aluminum Association designations). Note that 8921
and 8111 household foils are described in examples later.
[0038] In one embodiment, the thickness of the casting strip is
less than about 6 mm. In another embodiment, the thickness of the
casting strip is from about 1 mm to about 5 mm. In a further
embodiment, the thickness of the casting strip is from about 2 mm
to about 4 mm.
[0039] In the second step, the strip cast is then hot rolled
in-line to a desired thickness with a minimum of 10% reduction in
thickness at about 720.degree. F. in one embodiment of the present
invention. The term "hot rolled in-line" is defined as any rolling
of aluminum cast strip directly from the caster at a mill inlet
temperature of above about 700.degree. F. In one embodiment, the
temperature of the feedstock material after hot rolling is below
about 700.degree. F. at the coiler.
[0040] A combination of hot- and warm rolling steps in-line can be
used to reduce the material to the desired thickness. This is
limited only by the number of mill stands in-line with the
caster.
[0041] In the third step, the feedstock material is hot/warm
coiled. In one embodiment, the temperature of the feedstock
material is below about 700.degree. F. at the coilers.
[0042] In the fourth step, the coil is un-coiled so that the
aluminum alloy casting strip may be cold rolled to the required
product thickness for the fifth step. In one embodiment, cold
rolling takes place between a pair of rotating rolls at room
temperature. In another embodiment, the cold rolling step may be
broken down to various steps depending on the product thickness.
For example, the feedstock material may be rolled to a breakdown
gauge before rolling the feedstock material to the final gauge
needed.
[0043] Depending on the final gauge desired, this results in a foil
product having a substantially uniform thickness between about 5 to
about 150 micrometers. Table 1 shows a comparison of properties of
the household foil made from the present invention of 8921 aluminum
alloy with a typical commercial household aluminum foil.
TABLE-US-00001 TABLE 1 anneal thickness tensile strength yield
strength elongation (min.) Mullen product F./hr inch ksi ksi % psi
Micromill 8921 550 F./4 hr 0.000568 20.8 17.0 5.9 21.3 Micromill
8921 600 F./4 hr 0.000628 20.6 15.4 6.8 23.8 Micromill 8921 650
F./4 hr 0.000606 19.7 14.9 6.2 22.6 ReynoldsWrap 0.000634 12.3 6.6
5.1 13.7 anneal thickness tensile strength yield strength
elongation Mullen C./hr .mu.m MPa MPa % kPa Micromill 8921 288 C./4
hr 14.4 143.4 117.2 5.9 146.8 Micromill 8921 316 C./4 hr 16.0 142.0
106.2 6.8 164.1 Micromill 8921 343 C./4 hr 15.4 135.8 102.7 6.2
155.8 ReynoldsWrap 16.1 84.8 45.5 5.1 94.4 Notes: 1. ReynoldsWrap
values are averages for the standard product sold under this brand
name. 2. Yield strength is not specified for household foil.
[0044] Table 2 shows a comparison of properties of the household
foil made from the present invention of 8111 aluminum alloy with a
typical commercial household aluminum foil.
TABLE-US-00002 TABLE 2 anneal thickness tensile strength yield
strength elongation (min.) Mullen product F./hr inch ksi ksi % psi
Micromill 8111 525 F./4 hr 0.000572 20.6 17.4 3.1 12.9 Micromill
8111 600 F./4 hr 0.000599 15.1 8.0 5.3 12.0 Micromill 8111 650 F./4
hr 0.000610 14.0 6.8 5.8 16.0 Reynolds Wrap (mean values) 0.000634
12.3 6.6 5.1 13.7 Specifications 0.00064 +/- 10% 11.2-12.7 4.2 11.5
anneal thickness tensile strength yield strength elongation (min.)
Mullen C./hr .mu.m MPa MPa % kPa Micromill 8111 274 C./4 hr 14.5
142.0 120.0 3.1 88.9 Micromill 8111 316 C./4 hr 15.2 104.1 55.2 5.3
82.7 Micromill 8111 343 C./4 hr 15.5 96.5 46.9 5.8 110.3 Reynolds
Wrap (mean values) 16.1 84.8 45.5 5.1 94.4 Specifications 16.3 +/-
10% 77.2-87.6 4.2 79.3 Notes: 1. Reynolds Wrap values are averages
for the standard product sold under this brand name. 2. Yield
strength is not specified for household foil.
[0045] In the fifth step, the finished gauge product may optionally
be subjected to a partial or full anneal treatment depending on the
application or supplied in as-rolled condition.
[0046] The casting strip is substantially free of beta
intermetallic phase particles which results in a foil that is also
free of beta intermetallic phase particles. Determination of the
presence of beta intermetallic phase particles is conducted by
microscope.
[0047] In one embodiment, the present invention provides a method
of making feedstock for aluminum foil without the use of a grain
refiner, intermediate anneals or homogenization. This results in
improved properties of the resultant aluminum foils for the same
alloy. For example, some of the improved alloy properties include a
higher strength, ductility and burst pressure. Note that this
method of making feedstock for metal foil may be used to
manufacture fin products.
[0048] In another embodiment, the present method produces a
feedstock product with improved properties.
[0049] In one embodiment, the product comprises a 1xxx, 3xxx and
8xxx series aluminum alloy made by a non-ingot casting process
where the aluminum alloy has a thickness of about 5 micrometers to
about 150 micrometers for a foil product. The product has an
O-temper tensile strength, an O-temper elongation, and an O-temper
Mullen pressure that are at least 10% greater compared to the
average values of the same alloy in O-temper cast using a slab or
commercially available roll-casting process. The product is also
substantially free of pinholes caused by centerline segregation of
intermetallic particles.
[0050] In another embodiment, the product comprises a 8111 aluminum
alloy made by a non-ingot casting process where the aluminum alloy
has a thickness of about 5 micrometers to about 150 micrometers for
a foil product. The product has a tensile strength in O-temper, an
elongation in O-temper, and a Mullen pressure in O-temper that are
at least 10% greater than the average values of standard 8111 alloy
in O-temper. The product is substantially free of pinholes caused
by centerline segregation of intermetallic particles. The product
demonstrates the same foldability as ReynoldsWrap.RTM..
[0051] In another embodiment, the product comprises an 8921
aluminum alloy made by a non-ingot casting process where the
aluminum alloy has a thickness of about 5 micrometers to about 150
micrometers for a foil product. The product has a tensile strength
in O-temper, an elongation in O-temper, and a Mullen pressure in
O-temper that are at least 10% greater than the average values of
standard 8921 alloy in O-temper. The product is substantially free
of pinholes caused by centerline segregation of intermetallic
particles in the feedstock material.
[0052] Examples of the improved properties of the feedstock
products for the 8921 aluminum alloy may be found in Table 1.
Examples of the improved properties of the feedstock products for
the 8111 aluminum alloy may be found in Table 2.
[0053] FIG. 3 shows a three layered casting strip 11 produced by
the present method. Casting strip 11 includes an upper and lower
shell 12 and 13 and a central layer 14 which sandwiched between the
upper and lower shell 12 and 13, respectively. The center layer is
substantially free of harmful intermetallic particle stringers.
[0054] FIG. 4 shows a photomicrograph at 100 times magnification of
a transverse section of an as-cast strip of alloy 8921 produced
according to the present invention. This photomicrograph shows
refined microstructures, fine grains and no centerline
segregation.
[0055] In one embodiment, the non-ingot casting process is the
method of making a feedstock for metal foil described above.
EXAMPLE 1
[0056] A sample of alloy 8921 was initially strip cast to a
thickness of 2.7 mm and then was hot and warm rolled in line to
about 0.64 mm in two mill stands. The metal was coiled at
325.degree. F. Alloy 8921 was then un-coiled and subsequently cold
rolled to foil gauge, a thickness of 16 .mu.m in multiple rolling
passes.
EXAMPLE 2
[0057] A sample of alloy 8111 was strip cast to a thickness of 2.5
mm and then was hot and warm rolled in line to about 0.64 mm in two
mill stands. Alloy 8111 was then coiled at 325.degree. F. Alloy
8111 was then un-coiled and subsequently cold rolled to foil gauge
of 16 .mu.m in multiple rolling passes.
[0058] The final anneal for Example 1 was done at 525, 600 and 650
.degree. F. with a hold time of 4 hours. The final anneal for
Example 2 was done at 550, 600 and 650 .degree. F. with a hold time
of 4 hours. Mechanical property evaluations were carried out by
standard ASTM procedures E345-93. Mullen tests were done according
to ASTM #774-97. Pinhole determination was done by ASTM
B926-03.
[0059] While specific embodiments of the invention have been
described in detail, it will be appreciated by those skilled in the
art that various modifications and alternatives to those details
could be developed in light of the overall teachings of the
disclosure. Accordingly, the particular arrangements disclosed are
meant to be illustrative only and not limiting as to the scope of
the invention which is to be given the full breadth of the appended
claims and any and all equivalents thereof.
* * * * *