Note: Descriptions are shown in the official language in which they were submitted.
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ENGINEERED CAN BODY STOCK AND CAN END STOCK AND METHODS
FOR MAKING AND USING SAME
CROSS-REFERENCE TO RELATED APPLICATION
The present application claims priority to and filing benefit of U.S.
provisional
patent application Ser. No. 62/964,741, filed January 23, 2020, which is
incorporated
herein by reference in its entirety.
FIELD
The present disclosure is directed to aluminum alloy products and their
properties. The disclosure further relates to can body stock, can end stock,
and
methods of producing and processing the same.
BACKGROUND
Metal cans are well known and widely used as beverage containers. Beverage
can bodies are manufactured at high production rates and there is an ever-
increasing
demand to further increase the production rate of beverage cans by eliminating
metal-
related jams at the cupper press, as well as tear-offs and split domes at the
bodymakers. However, existing aluminum can body stock can cause a reduction in
productivity rates for can body production when tension and friction forces
are not
balanced during the can body production process. In addition, the inherent
formability
properties of existing anisotropic aluminum can end stock can cause draw-off
due to
uneven friction forces.
SUMMARY
Covered embodiments of the invention are defined by the claims, not this
summary. This summary is a high-level overview of various aspects of the
invention
and introduces some of the concepts that are further described in the Detailed
Description section below. This summary is not intended to identify key or
essential
features of the claimed subject matter, nor is it intended to be used in
isolation to
determine the scope of the claimed subject matter. The subject matter should
be
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understood by reference to appropriate portions of the entire specification,
any or all
drawings, and each claim.
In one aspect, aluminum alloy products having two different surface
roughnesses for use as can body sheet are disclosed herein. The aluminum alloy
products can have at least two surfaces, each independently having an average
surface
roughness that may be abbreviated as Ra. The aluminum alloy products in these
examples comprise a first surface having a first average surface roughness and
a
second surface having a second average surface roughness, wherein the first
average
surface roughness is at least 20 % lower than the second average surface
roughness,
as measured by a surface profilometer. In some examples, the first average
surface
roughness is less than 0.4 [tm. In some examples, the second average surface
roughness is greater than or equal to 0.4 [tm.
In some cases, the aluminum alloy is a 3xxx series aluminum alloy, such as an
AA3104 aluminum alloy. In some examples, the aluminum alloy comprises about
0.05 ¨0.25 wt. % Cu, up to about 0.8 wt. % Fe, about 0.8 ¨ 1.3 wt. % Mg, about
0.8 ¨
1.4 wt. % Mn, up to about 0.6 wt. % Si, up to about 0.1 wt. % Ti, up to about
0.25 wt.
% Zn, up to about 0.05 wt. % impurities, and Al.
In some examples, the aluminum alloy product has a thickness of less than
about 4 millimeters (mm).
In a second aspect, methods of making a can body from the can body sheet
described above are disclosed herein. The methods of making a can body include
contacting the sheet aluminum alloy product with a cupping press to form a
cup. The
cup comprises a cup inner surface having a cup inner surface average surface
roughness and a cup outer surface having a cup outer surface average surface
roughness, wherein the cup inner surface average surface roughness is greater
than
the cup outer surface average surface roughness. The method of making also
includes
the steps of contacting the cup inner surface with a punch sleeve and
contacting the
cup outer surface with an ironing die and ironing the cup to a desired height.
In some
examples, the methods further include trimming the walls to form the can body.
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In some examples, the cup has an outer surface average surface roughness Ra
(referred to herein as a cup outer surface average surface roughness) that is
less than
0.4 jim. In some examples, the cup has an inner surface average surface
roughness Ra
(referred to herein as a cup inner surface average surface roughness) that is
greater
than or equal to 0.4 jim. In some instances, the can body has an inner surface
having a
can body inner surface average surface roughness and an outer surface having a
can
body outer surface average surface roughness, wherein the can body inner
surface
average surface roughness is at least 10 % greater than the can body outer
surface
average surface roughness.
In a third aspect, aluminum alloy products for use as can end sheet are
disclosed herein. In some examples, the can end sheet has a surface percent
isotropy
of greater than 80 % as measured by confocal microscopy, and has a formability
distortion of less than 10 %. In some cases, the aluminum alloy product has an
isotropy of greater than 95 %.
In some examples, the aluminum alloy is a 5xxx series aluminum alloy, for
example, a 5182 aluminum alloy. In some examples, the aluminum alloy product
has
a Texture Aspect Ratio (Str) value of greater than 0.7, according to ISO
25178.
Other objects and advantages of the invention will be apparent from the
following detailed description of non-limiting examples.
BRIEF DESCRIPTION OF THE FIGURES
Figure 1 is a schematic drawing of an aluminum alloy cup according to some
examples.
Figure 2 is a schematic drawing of a cross section of an aluminum alloy
product according to some examples.
Figure 3 is a schematic drawing of a stamped can end according to some
examples.
DETAILED DESCRIPTION
Described herein are aluminum alloys with improved formability, aluminum
alloy products, and methods for making the products. The aluminum alloy
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compositions and methods described herein provide improved aluminum alloy
sheets
for the efficient production of aluminum alloy products, such as aluminum can
bodies
having two different surface roughnesses and can ends having decreased
anisotropy.
Definitions and Descriptions:
The terms "invention," "the invention," "this invention," and "the present
invention" used herein are intended to refer broadly to all of the subject
matter of this
patent application and the claims below. Statements containing these terms
should be
understood not to limit the subject matter described herein or to limit the
meaning or
scope of the patent claims below.
As used herein, the meaning of "a," "an," or "the" includes singular and
plural
references unless the context clearly dictates otherwise.
In this description, reference is made to alloys identified by aluminum
industry
designations, such as "series" or "3xxx." For an understanding of the number
.. designation system most commonly used in naming and identifying aluminum
and its
alloys, see "International Alloy Designations and Chemical Composition Limits
for
Wrought Aluminum and Wrought Aluminum Alloys" or "Registration Record of
Aluminum Association Alloy Designations and Chemical Compositions Limits for
Aluminum Alloys in the Form of Castings and Ingot," both published by The
Aluminum Association.
As used herein, a plate generally has a thickness of greater than about 15 mm.
For example, a plate may refer to an aluminum product having a thickness of
greater
than about 15 mm, greater than about 20 mm, greater than about 25 mm, greater
than
about 30 mm, greater than about 35 mm, greater than about 40 mm, greater than
about
45 mm, greater than about 50 mm, or greater than about 100 mm.
As used herein, a shate (also referred to as a sheet plate) generally has a
thickness of from about 4 mm to about 15 mm. For example, a shate may have a
thickness of about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about
9
mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, or about
15 mm.
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As used herein, a sheet generally refers to an aluminum product having a
thickness of less than about 4 mm. For example, a sheet may have a thickness
of less
than about 4 mm, less than about 3 mm, less than about 2 mm, less than about 1
mm,
less than about 0.5 mm, less than about 0.3 mm, or less than about 0.1 mm.
As used herein, the term foil indicates an alloy thickness in a range of up to
about 0.2 mm (i.e., 200 microns (.1m)). For example, a foil may have a
thickness of
up to 10 [tm, 20 [tm, 30 [tm, 40 [tm, 50 [tm, 60 [tm, 70 [tm, 80 [tm, 90 [tm,
100 [tm,
110 [tm, 120 [tm, 130 [tm, 140 [tm, 150 [tm, 160 [tm, 170 [tm, 180 [tm, 190
[tm, or
200
All ranges disclosed herein are to be understood to encompass any and all
subranges subsumed therein. For example, a stated range of "1 to 10" should be
considered to include any and all subranges between (and inclusive of) the
minimum
value of 1 and the maximum value of 10; that is, all subranges beginning with
a
minimum value of 1 or more, e.g., 1 to 6.1, and ending with a maximum value of
10
or less, e.g., 5.5 to 10.
The aluminum alloys herein are described in terms of their elemental
composition in weight percentage (wt. %) based on the total weight of the
alloy. In
certain examples of each alloy, the remainder is aluminum, with a maximum wt.
% of
0.15% for the sum of the impurities.
Aluminum Can Bodies and Methods of Making the Same
Described herein is an aluminum alloy product for use, for example, as an
aluminum can body. The aluminum alloy product can be a sheet that has a
substantially planar shape with at least two surfaces, such as a top surface
and a
bottom surface. "Substantially" planar, for purposes of this application,
means having
a measurement in the z-axis that is no more than 50 %, no more than 40 % , no
more
than 30 % , no more than 20 %, no more than 10 % , no more than 5 % ,or no
more
than 1 % of the measurement in either the x axis or the y axis. For example, a
sheet
that is substantially could have measurements of 1 meter in the x-axis, 1000
meters in
the y-axis, and 1 millimeter in the z-axis.
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In some examples, the aluminum alloy product is a can body sheet.
Differences in the surface roughness of the two sides of the sheet lead to
improved
processing qualities compared to conventional can body sheet that lacks any
substantial difference in surface roughnesses. In other examples, thicker or
thinner
aluminum alloy products, such as a shate or a foil, respectively, can have
different
surface roughnesses leading to improved processing characteristics.
The top and bottom surfaces of the aluminum alloy product can have different
surface roughnesses Ra, such as a first surface having a first average surface
roughness and a second surface having a second average surface roughness. In
some
cases, the first average surface roughness is at least 20 % lower than the
second
average surface roughness. In other cases, the first average surface roughness
is at
least 21 % lower, at least 22 % lower, at least 23 % lower, at least 24 %
lower, at least
25 % lower, at least 26 % lower, at least 27 % lower, at least 28 % lower, at
least 29
% lower, at least 30 % lower, at least 35 % lower, at least 40 % lower, at
least 45 %
lower, at least 50 % lower, at least 55 % lower, at least 50 % lower, at least
65 %
lower, at least 70 % lower, at least 75 % lower, at least 80 % lower, at least
85 %
lower, at least 90 % lower, or at least 95 % lower than the second average
surface
roughness. For example, if the first side surface roughness is measured and
reported
as an Ra value, when the Ra value of the second side surface is 1.0 [tm, then
the
maximum surface roughness Ra value of the first surface would be 0.80 jim when
the
first average surface roughness is at least 20 % lower than the second average
surface
roughness.
Surface roughness may be measured by any method known in the art. In
general, a surface profilometer is used to measure and describe the surface
features,
which is reported as "average surface roughness." The term average surface
roughness is used for purposes herein to convey that the surface features may
be
regular and repeating in a consistent manner, like the surface features of an
egg
carton, or irregular and not repeating in a consistent manner, like the
surface of a
mountain range. In general, the "average surface roughness" measures and
reports the
average distance from a plane. For example, a two dimensional (2D) or a three
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dimensional (3D) profilometer may be used to determine average surface
roughness.
In some cases, the profilometer employs a stylus to measure average surface
roughness; in other cases, optical methods may be used. A person of ordinary
skill
will understand that even though one particular method may be specified, any
method
capable of detecting a difference in the average roughness of two different
surfaces
may be used, and the difference between the two measurements may be expressed
as
a percentage. In some examples, the average surface roughness is measured by
confocal microscopy. The surfaces are characterized herein by various
parameters,
including Ra and Rz, which are measured in micrometers (microns) and are known
to
those of skill in the art. Optionally, the parameters can be measured using
the
MountainsMap Surface Imaging and Metrology software (Digital Surf; Besancon,
France). All roughness values can be mechanically measured with a standard
stylus.
In other examples, the average surface roughness is measured and reported as
Str
according to ISO 25178 [2019]. The Str value is the ratio of the shortest
wavelength
to the longest wavelength measured in any direction relative to the rolling
direction.
During the production of can bodies, such as beverage can bodies, a can body
sheet is subjected to two-piece drawing and wall ironing. The can body sheet
is first
contacted with a cupping press to form a cup, and then the cup is transferred
to a
punch sleeve for drawing and ironing. As shown in Figure 1, the cup 10 has an
inner
surface 11 and an outer surface 12.
During drawing and ironing, it is necessary to balance the friction between
the
punch sleeve and the inner surface of the cup with the tension between the
ironing
dies and the outer surface of the cup. Not intending to be bound by theory,
when
tension and friction are balanced, fractures are reduced. Traditional methods
of
balancing tension and friction involve adding a lubricant to the outer surface
that
contacts the ironing die. With the materials and processes disclosed herein,
rather than
reducing tension between the outer surface of the cup and the ironing die
(e.g., by
using additional lubricant), the friction between the punch sleeve and the cup
inner
surface is increased by having a rougher surface in contact with the punch
sleeve,
with the smoother outer surface in contact with the ironing die. Thus, the
materials
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and methods disclosed herein have the advantages of reducing can body
fractures and
also reducing the amount of lubricant. Although the materials and methods are
described in some instances regarding can body sheet, a person of ordinary
skill will
understand that the materials and methods are applicable to any aluminum alloy
product that is punched, stamped, drawn and/or ironed, when it would be
beneficial to
increase friction between a machine component and a surface of an aluminum
alloy
product. Thus, the aluminum alloy product can be a shate, a sheet, or a foil.
Further,
the person of ordinary skill will understand that the average surface
roughnesses
required to balance tension and friction, as well as the difference between
the two
average surface roughnesses required, may vary according to the particular
design of
the punch sleeves and the ironing dies and the particular aluminum alloy
product.
In some examples, the first surface, which may correspond to the outer surface
12 of the cup 10, is smoother than the second surface, which may correspond to
the
inner surface 11 of the cup 10. In this way, the first average surface
roughness Ra of
the first surface is lower than the second average surface roughness Ra of the
second
surface. A smoother surface will have fewer and/or smaller topographical
features
such as bumps, ridges, lines, and/or projections than a rougher surface. In
some
examples, the first average surface roughness Ra is less than 0.4 jim. In
other
examples, the first average surface roughness Ra is less than 0.38 [tm, less
than 0.36
[tm, less than 0.34 [tm, less than 0.32 [tm, less than 0.28 [tm, less than
0.26 [tm, less
than 0.24 [tm, less than 0.22 [tm, less than 0.2 [tm, less than 0.18 [tm, less
than 0.16
[tm, less than 0.14 [tm, less than 0.12 [tm, less than 0.1 [tm, less than 0.08
[tm, less
than 0.06 [tm, less than 0.04 [tm, less than 0.02 [tm, or less than 0.01
In some examples, the second average surface roughness Ra is greater than or
equal to 0.4 jim. In other examples, the second average surface roughness Ra
is
greater than or equal to 0.6 [tm, greater than or equal to 0.8 [tm, greater
than or equal
to 1.0 [tm, greater than or equal to 1.5 [tm, greater than or equal to 2 [tm,
greater than
or equal to 2.5 [tm, greater than or equal to 3 [tm, greater than or equal to
3.5 [tm,
greater than or equal to 4 [tm, greater than or equal to 4.5 [tm, greater than
or equal to
5 [tm, greater than or equal to 5.5 [tm, greater than or equal to 6 [tm,
greater than or
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equal to 6.5 [tm, greater than or equal to 7 [tm, greater than or equal to 7.5
[tm,
greater than or equal to 8 [tm, greater than or equal to 8.5 [tm, greater than
or equal to
9 [tm, greater than or equal to 9.5 [tm, greater than or equal to 10 [tm, or
greater than
or equal to 15
In another aspect, methods of making aluminum can bodies are described
herein. The methods of making a can body comprise the steps of contacting an
aluminum alloy product having two different surface roughnesses with a cupping
press to form a cup comprising a cup inner surface having a cup inner surface
average
surface roughness and a cup outer surface having a cup outer surface average
surface
roughness, wherein the inner surface average surface roughness is greater than
the
outer surface average surface roughness; contacting the cup inner surface with
a
punch sleeve and contacting the cup outer surface with an ironing die; and
ironing the
cup to a desired height. Because the rougher surface of the aluminum alloy
product is
in contact with the punch sleeve, friction between the punch sleeve and the
rougher
.. surface balances the tension between the ironing die and the smoother
surface. In
some examples, the methods further comprise the step of trimming the walls to
form
the can body.
Any of the aluminum alloy products (such as a shate, a sheet, or a foil)
described above may be used, as long as the aluminum alloy product has a
difference
in roughness of two of its sides. In some examples, the outer surface average
surface
roughness Ra of the cup is less than 0.4 jim. In other examples, the outer
surface
average surface roughness Ra is less than 0.38 [tm, less than 0.36 [tm, less
than 0.34
[tm, less than 0.32 [tm, less than 0.3 [tm, less than 0.28 [tm, less than 0.26
[tm, less
than 0.24 [tm, less than 0.22 [tm, less than 0.2 [tm, less than 0.18 [tm, less
than 0.16
[tm, less than 0.14 [tm, less than 0.12 [tm, less than 0.1 [tm, less than 0.08
[tm, less
than 0.06 [tm, less than 0.04 [tm, less than 0.02 [tm, or less than 0.01
In some examples, the inner surface average surface roughness of the cup Ra
is greater than or equal to 0.4 jim. In other examples, the inner surface
average
surface Ra is greater than or equal to 0.45 [tm, greater than or equal to 0.5
[tm, greater
.. than or equal to 0.6 [tm, greater than or equal to 0.8 [tm, greater than or
equal to 1.0
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[tm, greater than or equal to 1.5 [tm, greater than or equal to 2 [tm, greater
than or
equal to 2.5 [tm, greater than or equal to 3 [tm, greater than or equal to 3.5
[tm,
greater than or equal to 4 [tm, greater than or equal to 4.5 [tm, greater than
or equal to
[tm, greater than or equal to 5.5 [tm, greater than or equal to 6 [tm, greater
than or
5 equal to 6.5 [tm, greater than or equal to 7 [tm, greater than or equal
to 7.5 [tm,
greater than or equal to 8 [tm, greater than or equal to 8.5 [tm, greater than
or equal to
9 [tm, greater than or equal to 9.5 [tm, greater than or equal to 10 [tm, or
greater than
or equal to 15
Can bodies manufactured using the products and methods described herein
differ from a conventional can body in that at least a portion of the can body
inner
surface has an average surface roughness that is greater than the average
surface
roughness of the can body outer surface. Thus, in some examples, the can body
comprises an inner surface having a can body inner surface average surface
roughness
and an outer surface having a can body outer surface average surface
roughness,
where the can body inner surface average surface roughness is at least 20 %
greater
than the can body outer surface average surface roughness. In other cases, the
can
body inner surface average surface roughness is at least 22 % greater, at
least 24 %
greater, at least 25 % greater, at least 26 % greater, at least 28 % greater,
at least 30 %
greater, at least 35 % greater, at least 40 % greater, at least 45 % greater,
at least 50 %
greater, at least 55 % greater, at least 60 % greater, at least 65 % greater,
at least 70 %
greater, at least 75 % greater, at least 80 % greater, at least 85 % greater,
at least 90 %
greater, or at least 95 % greater than the can body outer surface average
surface
roughness.
The aluminum alloy products and methods described herein can be used for
preparing beverage cans, food containers, or any other desired application. In
some
examples, the aluminum alloy products and methods can be used to prepare
beverage
can bodies.
Aluminum alloys for use in the products and methods described herein include
3xxx series aluminum alloys. Suitable 3xxx series aluminum alloys include, for
example, AA3002, AA3102, AA3003, AA3103, AA3103A, AA3103B, AA3203,
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AA3403, AA3004, AA3004A, AA3104, AA3204, AA3304, AA3005, AA3005A,
AA3105, AA3105A, AA3105B, AA3007, AA3107, AA3207, AA3207A, AA3307,
AA3009, AA3010, AA3110, AA3011, AA3012, AA3012A, AA3013, AA3014,
AA3015, AA3016, AA3017, AA3019, AA3020, AA3021, AA3025, AA3026,
AA3030, AA3130, and AA3065. In some examples, the aluminum alloy is AA3104.
In some examples, the alloys for use in the products and methods described
herein can have the following elemental composition as provided in Table 1.
Table 1
Element Weight Percentage (wt. %)
Cu 0.05 ¨ 0.4
Fe 0 ¨ 0.9
Mg 0.8 ¨ 3.0
Mn 0.8 ¨ 2.0
Si 0 ¨ 0.7
Ti 0 ¨ 0.1
Zn 0 ¨ 0.25
Cr 0 ¨ 0.4
Others 0 ¨ 0.05 (each)
0 ¨ 0.15 (total)
Al Remainder
In some examples, the alloy can have the following elemental composition as
provided in Table 2.
Table 2
Element Weight Percentage (wt. %)
Cu 0.05 ¨ 0.25
Fe 0 ¨ 0.8
Mg 0.8 ¨ 1.3
Mn 0.8 ¨ 1.4
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Si 0 - 0.6
Ti 0 - 0.1
Zn 0 - 0.25
Others 0 - 0.05 (each)
0 - 0.15 (total)
Al Remainder
In some examples, the aluminum alloy comprises 0.05 - 0.4 wt. % Cu, up to
about 0.9 wt. % Fe, about 0.8 - 3.0 wt. % Mg, about 0.8 - 2.0 wt. % Mn, up to
about
0.7 wt. % Si, up to about 0.1 wt. % Ti, up to about 0.25 wt. % Zn, up to about
0.15
wt. % impurities, and Al.
In some examples, the aluminum alloy comprises 0.05 - 0.25 wt. % Cu, up to
about 0.8 wt. % Fe, about 0.8 - 2.8 wt. % Mg, about 0.8- 1.4 wt. % Mn, up to
about
0.6 wt. % Si, up to about 0.1 wt. % Ti, up to about 0.25 wt. % Zn, up to about
0.15
wt. % impurities, and Al.
In some examples, the aluminum alloy comprises 0.05 - 0.3 wt. % Cu, about
0.4 -about 0.8 wt. % Fe, about 0.8 - 2.8 wt. % Mg, about 0.1 - 1.5 wt. % Mn,
about
0.25 -0.6 wt. % Si, up to about 0.1 wt. % Ti, about 0.1 -0.25 wt. % Zn, up to
about
0.35 wt. % Cr, up to about 0.15 wt. % impurities, and Al.
In some examples, the alloys described herein include copper (Cu) in an
amount of from about 0.05 % to about 0.40 % (e.g., from about 0.05 % to about
0.35
% or from about 0.10% to about 0.30%) based on the total weight of the alloy.
For
example, the alloy can include 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11
%, 0.12%, 0.13 %, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21 %,
0.22%, 0.23 %, 0.24%, 0.25 %, 0.26 %, 0.27 %, 0.28 %, 0.29%, 0.30%, 0.31 %,
0.32 %, 0.33 %, 0.34 %, 0.35 %, 0.36 %, 0.37 %, 0.38 %, 0.39 %, or 0.40 % Cu.
All
are expressed in wt. %.
In some examples, the alloys described herein include iron (Fe) in an amount
of up to about 0.9 % (e.g., from about 0.3 % to about 0.85 % or from about 0.4
% to
about 0.8 %) based on the total weight of the alloy. For example, the alloy
can include
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0%, 0.05 %, 0.10%, 0.15 %, 0.20%, 0.25 %, 0.26%, 0.27 %, 0.28 %, 0.29%, 0.30
%, 0.31 %, 0.32%, 0.33 %, 0.34%, 0.35 %, 0.36%, 0.37 %, 0.38 %, 0.39%, 0.40%,
0.41 %, 0.42 %, 0.43 %, 0.44 %, 0.45 %, 0.46 %, 0.47 %, 0.48 %, 0.49 %, 0.5 %,
0.51 %, 0.52 %, 0.53 %, 0.54 %, 0.55 %, 0.56 %, 0.57 %, 0.58 %, 0.59 %, 0.6 %,
0.61 %, 0.62 %, 0.63 %, 0.64 %, 0.65 %, 0.66 %, 0.67 %, 0.68 %, 0.69 %, 0.7 %,
0.71 %, 0.72 %, 0.73 %, 0.74 %, 0.75 %, 0.76 %, 0.77 %, 0.78 %, 0.79 %, 0.8 %,
0.81 %, 0.82 %, 0.83 %, 0.84 %, 0.85 %, 0.86 %, 0.87 %, 0.88 %, 0.89 %, or 0.9
%
Fe. In some cases, Fe is not present in the alloy (i.e., 0 %).All are
expressed in wt. %.
In some examples, the alloys described herein include magnesium (Mg) in an
amount of from about 0.8 % to about 3.0 % (e.g., from about 0.8 % to about 2.8
% or
from about 1.0% to about 2.5 %) based on the total weight of the alloy. For
example,
the alloy can include 0.8 %, 0.81 %, 0.82 %, 0.83 %, 0.84 %, 0.85 %, 0.86 %,
0.87 %,
0.88 %, 0.89 %, 0.9 %, 0.91 %, 0.92 %, 0.93 %, 0.94 %, 0.95 %, 0.96 %, 0.97 %,
0.98%, 0.99%, 1.0%, 1.1 %, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9
%, 2.0 %, 2.1 %, 2.2 %, 2.3 %, 2.4 %, 2.5 %, 2.6 %, 2.7 %, 2.8 %, 2.9 %, or
3.0 %
Mg. All are expressed in wt. %.
In some examples, the alloys described herein include manganese (Mn) in an
amount of from about 0.1 % to about 2.0% (e.g., from about 0.1 % to about 1.5
% or
from about 0.5 % to about 1.5 %) based on the total weight of the alloy. For
example,
the alloy can include 0.1 %, 0.11 %, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%,
0.18 %, 0.19 %, 0.2%, 0.21 %, 0.22%, 0.23 %, 0.24%, 0.25 %, 0.26%, 0.27 %,
0.28 %, 0.29 %, 0.3 %, 0.31 %, 0.32%, 033 %, 0.34%, 0.35 %, 0.36%, 0.37 %,
0.38
%, 0.39 %, 0.4 %, 0.41 %, 0.42 %, 0.43 %, 0.44 %, 0.45 %, 0.46 %, 0.47 %, 0.48
%,
0.49 %, 0.5 %, 0.51 %, 0.52 %, 0.53 %, 0.54 %, 0.55 %, 0.56 %, 0.57 %, 0.58 %,
0.59 %, 0.6 %, 0.61 %, 0.62 %, 0.63 %, 0.64 %, 0.65 %, 0.66 %, 0.67 %, 0.68 %,
0.69 %, 0.7 %, 0.71 %, 0.72 %, 0.73 %, 0.74 %, 0.75 %, 0.76 %, 0.77 %, 0.78 %,
0.79 %, 0.8 %, 0.81 %, 0.82 %, 0.83 %, 0.84 %, 0.85 %, 0.86 %, 0.87 %, 0.88 %,
0.89 %, 0.9 %, 0.91 %, 0.92 %, 0.93 %, 0.94 %, 0.95 %, 0.96 %, 0.97 %, 0.98 %,
0.99%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9 %, or 2.0
% Mn. All are expressed in wt. %.
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In some examples, the alloys described herein include silicon (Si) in an
amount of up to about 0.7 % (e.g., from about 0.25 % to about 0.6 % or from
about
0.3 % to about 0.55 %) based on the total weight of the alloy. For example,
the alloy
can include 0 %, 0.01 %, 0.02 %, 0.03 %, 0.04 %, 0.05 %, 0.06 %, 0.07 %, 0.08
%,
0.09%, 0.1%, 0.2%, 0.21 %, 0.22%, 0.23 %, 0.24%, 0.25%, 0.26%, 0.27%, 0.28
%, 0.29%, 0.3 %, 0.31 %, 0.32%, 0.33 %, 0.34%, 0.35 %, 0.36 %, 0.37 %, 0.38 %,
0.39 %, 0.4 %, 0.41 %, 0.42 %, 0.43 %, 0.44 %, 0.45 %, 0.46 %, 0.47 %, 0.48 %,
0.49 %, 0.5 %, 0.51 %, 0.52 %, 0.53 %, 0.54 %, 0.55 %, 0.56 %, 0.57 %, 0.58 %,
0.59 %, 0.6 %, 0.61 %, 0.62 %, 0.63 %, 0.64 %, 0.65 %, 0.66 %, 0.67 %, 0.68 %,
0.69 %, or 0.7 % Si. In some cases, Si is not present in the alloy (i.e., 0
%). All are
expressed in wt. %.
In some examples, the alloys described herein include titanium (Ti) in an
amount up to about 0.1 % (e.g., from about 0.01 % to about 0.08 % or from
about
0.02 % to about 0.05 %) based on the total weight of the alloy. For example,
the alloy
can include 0.01 %, 0.02 %, 0.03 %, 0.04 %, 0.05 %, 0.06 %, 0.07 %, 0.08 %,
0.09
or 0.1 % Ti. In some cases, Ti is not present in the alloy (i.e., 0 %). All
are
expressed in wt. %.
In some examples, the alloys described herein include zinc (Zn) in an amount
up to about 0.25 % (e.g., from about 0.01 % to about 0.25 % or from about 0.1
% to
about 0.2 %) based on the total weight of the alloy. For example, the alloy
can include
0.01 %, 0.02%, 0.03 %, 0.04%, 0.05 %, 0.06%, 0.07 %, 0.08 %, 0.09%, 0.1 %,
0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%,
0.21 %, 0.22 %, 0.23 %, 0.24 %, or 0.25 % Zn. In some cases, Zn is not present
in the
alloy (i.e., 0 %). All are expressed in wt. %.
In some examples, the alloys described herein include chromium (Cr) in an
amount up to about 0.4 % (e.g., from about 0.01 % to about 0.35 % or from
about
0.05 % to about 0.3 %) based on the total weight of the alloy. For example,
the alloy
can include 0.01 %, 0.02 %, 0.03 %, 0.04 %, 0.05 %, 0.06 %, 0.07 %, 0.08 %,
0.09
%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%,
0.2 %, 0.21 %, 0.22 %, 0.23 %, 0.24 %, 0.25 %, 0.26 %, 0.27 %, 0.28 %, 0.29 %,
0.3
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%, 0.31 %, 0.32%, 0.33 %, 0.34%, 0.35 %, 0.36%, 0.37 %, 0.38 %, 0.39%, or 0.4
% Cr. In some cases, Cr is not present in the alloy (i.e., 0 %). All are
expressed in wt.
%.
Optionally, the alloy compositions described herein can further include other
minor elements, sometimes referred to as impurities, in amounts of 0.05 % or
below,
0.04 % or below, 0.03 % or below, 0.02 % or below, or 0.01 % or below. These
impurities may include, but are not limited to Zr, Sn, Ga, Ca, Bi, Na, Pb, or
combinations thereof. Accordingly, Zr, Sn, Ga, Ca, Bi, Na, or Pb may be
present in
alloys in amounts of 0.05 % or below, 0.04 % or below, 0.03 % or below, 0.02 %
or
below or 0.01 % or below. In some cases, the sum of all impurities does not
exceed
0.15 % (e.g., 0.10 %). All are expressed in wt. %. The remaining percentage of
the
alloy is aluminum.
Aluminum Can Ends and Methods of Making the Same
Also described herein is an aluminum alloy product for use, for example, as
can end stock. The can end stock described herein has surfaces that are
substantially
isotropic, and exhibits improved formability over the standard can end stock
having
an anisotropic "directional" surface, referred to herein as the standard
directional
material. The increased formability of the can end stock described herein is
due, at
least in part, to its increased surface isotropy as compared to the standard
directional
material. "Substantially" isotropic, for purposes of this application, means
having at
least 70 %, at least 75 %, at least 80 %, at least 85 %, or at least 95 %
isotropy.
The aluminum alloy products described herein are less prone to issues
resulting from low formability, such as product cracking, particularly during
a
punching operation on a shell press. Not to be bound by theory, this is due,
in part, to
the fact that in the standard directional material, the friction in the
direction 90 to the
rolling direction is highest. In the standard directional material, the
forming loads are
increased due to direct impingement from the topographical peaks created with
a
standard roll ground surface. In the products described herein, however, the
number
of peaks is lowered by at least 10 % as compared to the standard directional
material.
For example, the number of peaks can be lowered by at least 20 %, at least 30
%, at
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least 40 %, at least 50 %, at least 60 %, at least 70 %, at least 80 %, at
least 90 % as
compared to the standard directional material. In some cases, no peaks are
present.
Thus, the friction is balanced in all directions and the extreme loads from
friction at
the 900 component are lowered. Moreover, when a circular product, such as a
can
end, is formed from standard directional material, the resulting shape is not
a perfect
circle, but is "off-drawn" into a subtle elliptical shape with the largest
diameter being
in the 90 direction. This is a direct result of the higher friction (and
hence higher
forming load) in the 90 direction. The operating window for forming can be
widened
with the surfaces described herein to manage the "off-drawn" phenomena.
The surface isotropy of the aluminum alloy product may be increased by any
known method, such as nanosecond laser micro texturing, electrodischarge
texturing,
or rolling with a modified a work roll or rolling in the cross direction. It
is not
necessary to change the metallurgical properties (including directionality or
anisotropy) of the center portion of the aluminum alloy product that result
from the
rolled production process; rather, benefits are present when the outer surface
isotropy
is increased.
Processing is improved by reducing anisotropy at least at the top and bottom
surfaces of the can end stock, whether or not some residual anisotropy remains
in the
center portion between the top and bottom surfaces of the can end stock. Thus,
in
some examples, the aluminum alloy product comprises a thickness having a top
portion, a center portion, and a bottom portion. In some examples, the top and
bottom
portions comprise 0.1 % of the thickness of the aluminum alloy product. For
example,
an aluminum alloy product may have a thickness of 200 [tm; when the top and
bottom
portions comprise 1 % of the thickness, they together measure 2 [tm, leaving
the
measurement of the center portion at 198 jim. In some examples, the top and
bottom
portions comprise 0.5 % of the thickness, 1 % of the thickness, 5 % of the
thickness,
10 % of the thickness, 15 % of the thickness, 20 % of the thickness, or 25 %
of the
thickness. In some examples, the top and bottom portions are of equal
measurement;
in other cases, the top and bottom portions are not of equal measurement. As
shown
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in Figure 2, a cross-section of an aluminum alloy product 20 comprises a top
portion
21, a center portion 22, and a bottom portion 23.
In some examples, the aluminum alloy product has a surface percent isotropy
of greater than 80 % as measured by confocal microscopy, and has a formability
distortion of less than 10 %. "Surface percent isotropy" for the purposes of
this
application refers to isotropy as measured on a surface (top and/or bottom) of
the
aluminum alloy product, even if the isotropy of the aluminum alloy product
varies
through the thickness of the aluminum alloy product. In some examples, the
aluminum alloy product comprises a surface percent isotropy of greater than 85
%,
greater than 90 %, greater than 95 %, greater than 97 %, greater than 98 %,
greater
than 99%, or 100%.
"Formability distortion" for purposes of this application refers to the
maximum off-drawn when an aluminum alloy product is stamped with a circular
die,
such as on a shelling press, expressed as a percent of the radius of the
circle. For
example, when a circle is stamped using a die with a 2.5 cm diameter, and the
stamped product is a perfect 2.5 cm diameter circle, the formability
distortion is zero.
However, if the stamped product has a radius at one or more points that
exceeds the
intended 2.5 cm diameter, then the formability distortion is nonzero. If the
maximum
radius in this example is 2.75 cm, then the formability distortion is 10
percent. ((2.75-
2.50/2.5) = 0.10, or 10%). In some examples, the formability distortion is
less than 9
%, less than 8 %, less than 7 %, less than 6 %, less than 5 %, less than 4 %,
less than
3 %, less than 2 %, less than 1 %, or zero. As shown in Figure 3, a stamped
can end
may be off-drawn from a perfect circle, shown in dotted line. The maximum
radius
31 is larger than the circle radius 32.
25 The aluminum alloy products useful for can end stock described herein
can
have any suitable gauge. In some examples, the aluminum alloy product can be a
sheet. The sheet can be used as can end stock.
In some examples, the aluminum alloy product is a sheet such as a can end
sheet. In some examples, the aluminum alloy is a 5xxx series aluminum alloy.
30 Suitable 5xxx series aluminum alloys include, for example, AA5005,
AA5005A,
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AA5205, AA5305, AA5505, AA5605, AA5006, AA5106, AA5010, AA5110,
AA5110A, AA5210, AA5310, AA5016, AA5017, AA5018, AA5018A, AA5019,
AA5019A, AA5119, AA5119A, AA5021, AA5022, AA5023, AA5024, AA5026,
AA5027, AA5028, AA5040, AA5140, AA5041, AA5042, AA5043, AA5049,
AA5149, AA5249, AA5349, AA5449, AA5449A, AA5050, AA5050A, AA5050C,
AA5150, AA5051, AA5051A, AA5151, AA5251, AA5251A, AA5351, AA5451,
AA5052, AA5252, AA5352, AA5154, AA5154A, AA5154B, AA5154C, AA5254,
AA5354, AA5454, AA5554, AA5654, AA5654A, AA5754, AA5854, AA5954,
AA5056, AA5356, AA5356A, AA5456, AA5456A, AA5456B, AA5556, AA5556A,
AA5556B, AA5556C, AA5257, AA5457, AA5557, AA5657, AA5058, AA5059,
AA5070, AA5180, AA5180A, AA5082, AA5182, AA5083, AA5183, AA5183A,
AA5283, AA5283A, AA5283B, AA5383, AA5483, AA5086, AA5186, AA5087,
AA5187, and AA5088. In some examples, the aluminum alloy comprises a 5182
aluminum alloy.
The anisotropy of the surface can be measured by the Texture Aspect Ratio
(Str), according to ISO 25178, as described above. The Str value is the ratio
of the
shortest wavelength to the longest wavelength measured in any direction
relative to
the rolling direction. In some examples, the Str value for the surface of
alloy sheet as
described herein is greater than about 0.7. For example, the Str value can be
0.71,
0.75, 0.8, 0.85, 0.9, 0.95, 0.96, 0.97, 0.98, 0.99 or 1Ø Conventional
aluminum alloy
sheets used to prepare can end stock, however, typically have an anisotropic
surface
texture. The Str value for the surface of a conventional alloy sheet is less
than 0.1.
The anisotropic nature of conventional can end stock can cause formability
issues,
such as split domes and tear offs. The aluminum alloy products useful for can
end
stock described herein are free of significant anisotropy.
Illustrations of Suitable Alloys, Products, and Methods
Illustration 1 is an aluminum alloy product, comprising a first surface having
a
first average surface roughness; and a second surface having a second average
surface
roughness, wherein the first average surface roughness is at least 20 % lower
than the
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second average surface roughness, as measured by a surface profilometer.
Illustration 2 is the aluminum alloy of any preceding or subsequent
illustration,
wherein the first average surface roughness is at least 30 % lower than the
second
average surface roughness.
Illustration 3 is the aluminum alloy of any preceding or subsequent
illustration,
wherein the first average surface roughness is less than 0.4
Illustration 4 is the aluminum alloy of any preceding or subsequent
illustration,
wherein the second average surface roughness is greater than or equal to 0.4
Illustration 5 is the aluminum alloy of any preceding or subsequent
illustration,
wherein the aluminum alloy product comprises a 3xxx series aluminum alloy.
Illustration 6 is the aluminum alloy of any preceding or subsequent
illustration,
wherein the 3xxx series aluminum alloy comprises an AA3104 aluminum alloy.
Illustration 7 is the aluminum alloy of any preceding or subsequent
illustration,
wherein the aluminum alloy product comprises about 0.05 ¨ 0.25 wt. % Cu, up to
about 0.8 wt. % Fe, about 0.8¨ 1.3 wt. % Mg, about 0.8¨ 1.4 wt. % Mn, up to
about
0.6 wt. % Si, up to about 0.1 wt. % Ti, up to about 0.25 wt. % Znõ up to about
0.05
wt. % impurities, and Al..
Illustration 8 is the aluminum alloy of any preceding or subsequent
illustration,
wherein the aluminum alloy product comprises a thickness of less than about 4
mm.
Illustration 9 is the aluminum alloy of any preceding or subsequent
illustration,
wherein the aluminum alloy product is an aluminum can body.
Illustration 10 is a method of making an aluminum can body, comprising
contacting the aluminum alloy product of claim 1 with a cupping press to form
a cup
comprising a cup inner surface corresponding to the second surface and having
a cup
inner surface average surface roughness and a cup outer surface corresponding
to the
first surface and having a cup outer surface average surface roughness,
wherein the
cup inner surface average surface roughness is greater than the cup outer
surface
average surface roughness; contacting the cup inner surface with a punch
sleeve and
contacting the cup outer surface with an ironing die; and ironing the cup to a
desired
height.
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Illustration 11 is the method of any preceding or subsequent illustration,
wherein the cup has walls and the method further comprises trimming the walls
to
form the can body, wherein the can body has a can body inner surface and a can
body
outer surface.
Illustration 12 is the method of any preceding or subsequent illustration,
wherein the cup outer surface average surface roughness is less than 0.4 [tm.
Illustration 13 is the method of any preceding or subsequent illustration,
wherein the cup inner surface average surface roughness is greater than or
equal to
0.4 [tm.
Illustration 14 is the method of any preceding or subsequent illustration,
wherein the aluminum can body comprises an inner surface having a can body
inner
surface average surface roughness and an outer surface having a can body outer
surface average surface roughness, wherein can body inner surface average
surface
roughness is at least 2 0% greater than the can body outer surface average
surface
roughness.
Illustration 15 is an aluminum alloy product comprising a surface percent
isotropy of greater than 80 % as measured by confocal microscopy, and
comprising a
formability distortion of less than 10 %.
Illustration 16 is the aluminum alloy of any preceding or subsequent
illustration, wherein the aluminum alloy product comprises an isotropy of
greater than
95%.
Illustration 17 is the aluminum alloy of any preceding or subsequent
illustration, wherein the aluminum alloy product comprises a 5xxx series
aluminum
alloy.
Illustration 18 is the aluminum alloy of any preceding or subsequent
illustration, wherein the 5xxx series aluminum alloy comprises a 5182 aluminum
alloy.
Illustration 19 is the aluminum alloy of any preceding or subsequent
illustration, wherein the aluminum alloy product is an aluminum can end.
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Illustration 20 is the aluminum alloy of any preceding or subsequent
illustration, wherein the aluminum alloy product comprises a Texture Aspect
Ratio
(Str) value of greater than 0.7, according to ISO 25178.
All patents, publications and abstracts cited above are incorporated herein by
reference in their entirety. Various embodiments of the invention have been
described
in fulfillment of the various objectives of the invention. It should be
recognized that
these embodiments are merely illustrative of the principles of the present
invention.
Numerous modifications and adaptations thereof will be readily apparent to
those
skilled in the art without departing from the spirit and scope of the present
invention
as defined in the following claims.
21
