U.S. patent number 3,670,401 [Application Number 05/031,461] was granted by the patent office on 1972-06-20 for method of fabricating aluminum alloy rod.
This patent grant is currently assigned to Southwire Company. Invention is credited to Roger J. Schoerner.
United States Patent |
3,670,401 |
Schoerner |
June 20, 1972 |
METHOD OF FABRICATING ALUMINUM ALLOY ROD
Abstract
An aluminum alloy wire having an electrical conductivity of at
least 61 percent based on the International Annealed Copper
Standard and unexpected properties of increased ultimate
elongation, bendability and fatigue resistance when compared to
conventional aluminum alloy wire of the same tensile strength. The
aluminum alloy wire contains substantially evenly distributed iron
aluminate inclusions in a concentration produced by the addition of
more than about 0.30 weight percent iron to an alloy mass
containing less than about 99.70 weight percent aluminum, no more
than 0.15 weight percent silicon, and trace quantities of
conventional impurities normally found within a commercial aluminum
alloy. The substantially evenly distributed iron aluminate
inclusions are obtained by continuously casting an alloy consisting
essentially of less than about 99.70 weight percent aluminum, more
than 0.30 weight percent iron, no more than 0.15 weight percent
silicon and trace quantities of typical impurities to form a
continuous aluminum alloy bar, hot-working the bar substantially
immediately after casting in substantially that condition in which
the bar is cast to form continuous rod which is subsequently drawn
into wire without intermediate anneals and annealed after the final
draw. After annealing, the wire has the aforementioned novel and
unexpected properties of increased ultimate elongation, electrical
conductivity of at least 61 percent of the International Annealed
Copper Standard, and increased bendability and fatigue
resistance.
Inventors: |
Schoerner; Roger J.
(Carrollton, GA) |
Assignee: |
Southwire Company (Carrollton,
GA)
|
Family
ID: |
21859581 |
Appl.
No.: |
05/031,461 |
Filed: |
April 1, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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814183 |
Apr 7, 1969 |
3512221 |
|
|
|
779376 |
Nov 27, 1968 |
|
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730933 |
May 21, 1968 |
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Current U.S.
Class: |
164/476; 164/477;
29/527.7; 420/537; 420/548 |
Current CPC
Class: |
C22F
1/04 (20130101); C22C 21/00 (20130101); B22D
11/0602 (20130101); Y10T 29/49991 (20150115) |
Current International
Class: |
C22F
1/04 (20060101); B22D 11/06 (20060101); C22C
21/00 (20060101); B22d (); B23p 017/00 () |
Field of
Search: |
;29/183.5,527.7,193
;164/57,76 ;75/138 ;148/2,32 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
R H. Harrington, "The Effects of Single Addition Metals on the
Recrystallizaiion, Electrical Conductivity and Rupture and Rupture
Strength of Pure Aluminum" Transactions of the American Society for
Metals, Volume 41, pages 443-459, 1949..
|
Primary Examiner: Moon; Charlie T.
Assistant Examiner: Reiley, III; Donald C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a division of copending application Ser. No.
814,183, filed Apr. 7, 1969, now U.S. Pat. No. 3,512,221, which
application is a continuation-in-part of copending application Ser.
No. 779,376, filed Nov. 27, 1968, now abandoned, which in turn, is
a continuation-in-part of copending application Ser. No. 730,933,
filed May 21, 1968, and now abandoned.
Claims
I claim:
1. Process for preparing an aluminum alloy wire having an
electrical conductivity of at least 61 percent IACS and iron
aluminate inclusions with a particle size of less than 2,000
angstrom units comprising the steps of:
a. Alloying from about 98.95 to about 99.54 weight percent
aluminum, from about 0.45 to about 0.95 weight percent iron, about
0.01 to about 0.15 weight percent silicon, and less than 0.05
weight percent each of trace elements selected from the group
consisting of vanadium, copper, manganese, zinc, boron and
titanium; the total weight percent of trace elements being no more
than 0.15 weight percent and the ratio of iron to silicon being at
least 8:1;
b. Casting the alloy into a continuous bar in a moving mold formed
by a groove in the periphery of a casting wheel and an endless belt
lying adjacent the groove along a portion of the periphery of the
wheel;
c. Hot-working the bar substantially immediately after casting
while the bar is in substantially that condition as cast by rolling
the bar in closed roll passes to obtain a continuous aluminum alloy
rod;
d. Drawing the rod with no preliminary or intermediate anneals to
form wire; and
e. Annealing or partially annealing the wire.
2. Process of claim 1 wherein step (a) comprises alloying from
about 98.95 to about 99.44 weight percent aluminum, about 0.55 to
about 0.95 weight percent iron, from about 0.01 to about 0.15
weight percent silicon, and less than 0.05 weight percent each of
trace elements selected from the group consisting of vanadium,
copper, manganese, zinc, boron and titanium.
3. Process of claim 1 wherein the individual trace element content
is from 0.0001 to 0.05 weight percent and the total trace element
content is from 0.004 to 0.15 weight percent.
4. Process of claim 1 wherein step (e) comprises batch annealing or
batch partially annealing the wire.
5. Process for preparing an aluminum alloy wire having an
electrical conductivity of at least 61 percent IACS comprising the
steps of:
a. Alloying from about 98.95 to about 99.54 weight percent aluminum
with about 0.45 to about 0.95 weight percent iron, about 0.01 to
about 0.15 weight percent silicon, and from 0.0001 to 0.05 weight
percent each of trace elements selected from the group consisting
of vanadium, copper, manganese, zinc, boron and titanium, the total
trace element content being from 0.004 to 0.15 weight percent.
b. Continuously casting the alloy into a continuous bar;
c. Continuously rolling the bar in substantially that condition in
which it was cast into a bar to form a continuous rod;
d. Drawing the rod with no preliminary or intermediate anneals to
form wire; and e. Annealing or partially annealing the wire.
6. Process of claim 20 wherein step (a) comprises alloying from
about 98.95 to about 99.44 weight percent aluminum, about 0.55 to
about 0.95 weight percent iron, from about 0.01 to about 0.15
weight percent silicon, and from 0.0001 to 0.05 weight percent each
of trace elements selected from the group consisting of vanadium,
copper, manganese, zinc, boron and titanium, the total trace
element content being from 0.004 to 0.15 weight percent.
7. Process for preparing an aluminum alloy rod comprising the steps
of:
a. Alloying from about 98.95 to about 99.54 weight percent
aluminum, from about 0.45 to about 0.95 weight percent iron, about
0.01 to about 0.15 weight percent silicon, and from 0.0001 to 0.05
weight percent each of trace elements selected from the group
consisting of vanadium, copper, manganese, zinc, boron and
titanium; the total weight percent of trace elements being from
0.004 to 0.15 weight percent and the ratio of iron to silicon being
at least 8:1;
b. Casting the alloy into a continuous bar in a moving mold formed
by a groove in the periphery of a casting wheel and an endless belt
lying adjacent the groove along a portion of the periphery of the
wheel; and
c. Hot-working the bar substantially immediately after casting
while the bar is in substantially that condition as cast by rolling
the bar in closed roll passes to obtain a continuous aluminum alloy
rod without having been subjected to any preliminary or
intermediate anneals.
8. Process of claim 7 wherein step (a) comprises alloying from
about 98.95 to about 99.44 weight percent aluminum, about 0.55 to
about 0.95 weight percent iron, from about 0.01 to about 0.15
weight percent silicon, and from 0.0001 to 0.05 weight percent each
of trace elements selected from the group consisting of vanadium,
copper, manganese, zinc, boron and titanium, the total trace
element content being from 0.004 to 0.15 weight percent.
9. Process for preparing an aluminum alloy wire having an
electrical conductivity of at least 61 percent IACS and iron
aluminate inclusions with a particle size of less than 2,000
angstrom units comprising the steps of:
a. Alloying from about 98.95 to about 99.54 weight percent
aluminum, from about 0.45 to about 0.95 weight percent iron, about
0.01 to about 0.15 weight percent silicon, and less than 0.05
weight percent each of trace elements selected from the group
consisting of vanadium, copper, manganese, zinc, boron and
titanium; the total weight percent of trace elements being no more
than 0.15 weight percent and the ratio of iron to silicon being at
least 8:1;
b. Casting the alloy to form a cast bar;
c. Hot-working the bar by rolling the bar in closed roll passes to
obtain an aluminum alloy rod;
d. Drawing the rod with no preliminary or intermediate anneals to
form wire; and
e. Annealing or partially annealing the wire.
10. Process for preparing an aluminum alloy wire having an
electrical conductivity of at least 61 percent IACS comprising the
steps of:
a. Alloying from about 98.95 to less than 99.44 weight percent
aluminum with about 0.55 to about 0.95 weight percent iron, about
0.01 to about 0.15 weight percent silicon, and from 0.0001 to 0.05
weight percent each of trace elements selected from the group
consisting of vanadium, copper, manganese, zinc, boron and
titanium, the total trace element content being from 0.004 to 0.15
weight percent.
b. Casting the alloy into a cast bar;
c. Hot-rolling the bar to form a rod;
d. Drawing the rod with no preliminary or intermediate anneals to
form wire; and
e. Annealing or partially annealing the wire.
11. Process for preparing an aluminum alloy rod comprising the
steps of:
a. Alloying from about 98.95 to about 99.54 weight percent
aluminum, from about 0.45 to about 0.95 weight percent iron, about
0.015 to about 0.15 weight percent silicon and from about 0.0001 to
0.05 weight percent each of trace elements selected from the group
consisting of vanadium, copper, manganese, zinc, boron, and
titanium; the total weight percent of trace elements being from
0.004 to 0.15 weight percent and the ratio of iron content to
silicon content being at least 8:1;
b. continuous casting the alloy to form a continuous cast bar; and
without any preliminary or intermediate anneals initiating hot
working the cast bar to form an aluminum alloy rod before the cast
bar has cooled to a temperature below its hot working
temperature.
12. Process for preparing an aluminum alloy wire having
substantially evenly distributed iron aluminate inclusions of a
particle size of less than 2,000 angstrom units and an electrical
conductivity of at least 61 percent IACS comprising the steps
of:
a. Alloying less than about 99.70 weight percent aluminum with more
than about 0.30 weight percent iron, no more than about 0.15 weight
percent silicon and trace quantities of impurities;
b. Casting the alloy into a bar;
c. Rolling the bar to form rod;
d. Drawing the rod with no preliminary or intermediate anneals to
form wire; and
e. Annealing or partially annealing the wire.
13. Process for preparing an aluminum alloy wire having
substantially evenly distributed iron aluminate inclusions of a
particle size of less than 2,000 angstrom units and an electrical
conductivity of at least 61 percent IACS comprising the steps
of:
a. Alloying less than about 99.70 weight percent aluminum with more
than about 0.30 weight percent iron, no more than about 0.15 weight
percent silicon and trace quantities of impurities;
b. Continuously casting the alloy into a continuous bar;
c. Continuously rolling the bar in substantially that condition in
which it was cast into a bar to form a continuous rod;
d. Drawing the rod with no preliminary or intermediate anneals to
form wire; and
e. Annealing or partially annealing the wire.
Description
This invention relates to an aluminum alloy wire suitable for use
as an electrical conductor and more particularly concerns an
aluminum alloy wire having an acceptable electrical conductivity
and improved elongation, bendability and tensile strength.
The use of various aluminum alloy wires (conventionally referred to
as EC wire) as conductors of electricity is well established in the
art. Such alloys characteristically have conductivities of at least
61 percent of the International Annealed Copper Standard
(hereinafter sometimes referred to as IACS) and chemical
constituents consisting of a substantial amount of pure aluminum
and small amounts of conventional impurities such as silicon,
vanadium, iron, copper, manganese, magnesium, zinc, boron and
titanium. The physical properties of prior aluminum alloy wire have
proven less than desirable in many applications. Generally
desirable percent elongations have been obtained only at less than
desirable tensile strengths and desirable tensile strengths have
been obtainable only at less than desirable percent elongations. In
addition, the bendability and fatigue resistance of prior aluminum
alloy wires has been so low that the prior wire has been generally
unsuitable for many otherwise desirable applications.
Thus, it becomes apparent that a need has arisen within the
industry for an aluminum alloy electrically conductive wire which
has both improved percent elongation and improved tensile strength,
and also possesses an ability to withstand numerous bends at one
point and to resist fatiguing during use of the conductor.
Therefore, it is an object of the present invention to provide an
aluminum alloy wire of acceptable conductivity and improved
physical properties such that the conductor may be used in new
applications. Another object of the present invention is to provide
an aluminum alloy wire having novel properties of increased
ultimate elongation and tensile strength, improved bendability and
fatigue resistance and acceptable electrical conductivity. These
and other objects, features and advantages of the present invention
will become apparent to those skilled in the art from a
consideration of the following detailed description of the
invention.
In accordance with this invention, the present aluminum alloy
electrically conductive wire is prepared from an alloy comprising
less than about 99.70 weight percent aluminum, more than about 0.30
weight percent iron, and no more than 0.15 weight percent silicon.
Preferably, the aluminum content of the present alloy comprises
from about 98.95 to less than about 99.45 weight percent with
particularly superior results being achieved when from about 99.15
to about 99.40 weight percent aluminum is employed. Preferably, the
iron content of the present alloy comprises about 0.45 weight
percent to about 0.95 weight percent with particularly superior
results being achieved when from about 0.50 weight percent to about
0.80 weight percent iron is employed. Preferably, no more than 0.07
weight percent silicon is employed in the present alloy. The ratio
between the percentage iron and the percentage silicon must be
1.99:1 or greater. Preferably, the ratio between percentage iron
and percentage silicon is 8:1 or greater. Thus, if the present
aluminum alloy contains an amount of iron within the low area of
the present range for iron content, the percentage of aluminum must
be increased rather than increasing the percentage of silicon
outside the ratio limitation previously specified. It has been
found that properly processed wire having aluminum alloy
constituents which fall within the above-specified ranges possesses
acceptable electrical conductivity and improved tensile strength
and ultimate elongation and in addition has a novel unexpected
property of surprisingly increased bendability and fatigue
resistance.
The present aluminum alloy is prepared by initially melting and
alloying aluminum with the necessary amounts of iron or other
constituents to provide the requisite alloy for processing.
Normally, the content of silicon is maintained as low as possible
without adding additional amounts to the melt. Typical impurities
or trace elements are also present within the melt, but only in
trace quantities such as less than 0.05 weight percent each with a
total content of trace impurities generally not exceeding 0.15
weight percent. Of course, when adjusting the amounts of trace
elements due consideration must be given to the conductivity of the
final alloy since some trace elements affect conductivity more
severely than others. The typical trace elements include vanadium,
copper, manganese, magnesium, zinc, boron and titanium. If the
content of titanium is relatively high (but still quite low
compared to the aluminum, iron and silicon content), small amounts
of boron may be added to tie-up the excess titanium and keep it
from reducing the conductivity of the wire.
Iron is the major constituent added to the melt to produce the
alloy of the present invention. Normally, about 0.80 weight percent
is added to the typical aluminum component used to prepare the
present alloy. Of course, the scope of the present invention
includes the addition of more or less iron together with the
adjustment of the content of all alloying constituents.
After alloying, the melted aluminum composition is continuously
cast into a continuous bar. The bar is then hot-worked in
substantially that condition in which it is received from the
casting machine. A typical hot-working operation comprises rolling
the bar in a rolling mill substantially immediately after being
cast into a bar.
One example of a continuous casting and rolling operation capable
of producing continuous rod as specified in this application is as
follows:
A continuous casting machine serves as a means for solidifying the
molten aluminum alloy metal to provide a cast bar that is conveyed
in substantially the condition in which it solidified from the
continuous casting machine to the rolling mill, which serves as a
means for hot-forming the cast bar into rod or another hot-formed
product in a manner which imparts substantial movement to the cast
bar along a plurality of angularly disposed axes.
The continuous casting machine is of conventional casting wheel
type having a casting wheel with a casting groove partially closed
by an endless belt supported by the casting wheel and an idler
pulley. The casting wheel and the endless belt cooperate to provide
a mold into one end of which molten metal is poured to solidify and
from the other end of which the cast bar is emitted in
substantially that condition in which it solidified.
The rolling mill is of conventional type having a plurality of roll
stands arranged to hot-form the cast bar by a series of
deformations. The continuous casting machine and the rolling mill
are positioned relative to each other so that the cast bar enters
the rolling mill substantially immediately after solidification and
in substantially that condition in which it solidified. In this
condition, the cast bar is at a hot-forming temperature within the
range of temperatures for hot-forming the cast bar at the
initiation of hot-forming without heating between the casting
machine and the rolling mill. In the event that it is desired to
closely control the hot-forming temperature of the cast bar within
the conventional range of hot-forming temperatures, means for
adjusting the temperature of the cast bar may be placed between the
continuous casting machine and the rolling mill without departing
from the inventive concept disclosed herein.
The roll stands each include a plurality of rolls which engage the
cast bar. The rolls of each roll stand may be two or more in number
and arranged diametrically opposite from one another or arranged at
equally spaced positions about the axis of movement of the cast bar
through the rolling mill. The rolls of each roll stand of the
rolling mill are rotated at a predetermined speed by a power means
such as one or more electric motors and the casting wheel is
rotated at a speed generally determined by its operating
characteristics. The rolling mill serves to hot-form the cast bar
into a rod of a cross-sectional area substantially less than that
of the cast bar as it enters the rolling mill.
The peripheral surfaces of the rolls of adjacent roll stands in the
rolling mill change in configuration; that is, the cast bar is
engaged by the rolls of successive roll stands with surfaces of
varying configuration, and from different directions. This varying
surface engagement of the cast bar in the roll stands functions to
knead or shape the metal in the cast bar in such a manner that it
is worked at each roll stand and also to simultaneously reduce and
change the cross-sectional area of the cast bar into that of the
rod.
As each roll stand engages the cast bar, it is desirable that the
cast bar be received with sufficient volume per unit of time at the
roll stand for the cast bar to generally fill the space defined by
the rolls of the roll stand so that the rolls will be effective to
work the metal in the cast bar. However, it is also desirable that
the space defined by the rolls of each roll stand not be overfilled
so that the cast bar will not be forced into the gaps between the
rolls. Thus, it is desirable that the rod be fed toward each roll
stand at a volume per unit of time which is sufficient to fill, but
not overfill, the space defined by the rolls of the roll stand.
As the cast bar is received from the continuous casting machine, it
usually has one large flat surface corresponding to the surface of
the endless band and inwardly tapered side surfaces corresponding
to the shape of the groove in the casting wheel. As the cast bar is
compressed by the rolls of the roll stands, the cast bar is
deformed so that it generally takes the cross-sectional shape
defined by the adjacent peripheries of the rolls of each roll
stand.
Thus, it will be understood that with this apparatus, cast aluminum
alloy rod of an infinite number of different lengths is prepared by
simultaneous casting of the molten aluminum alloy and hot-forming
or rolling the cast aluminum bar.
The continuous rod produced by the casting and rolling operation is
then processed in a reduction operation designed to produce
continuous wire of various gauges. The unannealed rod i.e., as
rolled to f temper) is cold-drawn through a series of progressively
constricted dies, without intermediate anneals, to form a
continuous wire of desired diameter. At the conclusion of this
drawing operation, the alloy wire will have an excessively high
tensile strength and an unacceptably low ultimate elongation, plus
a conductivity below that which is industry accepted as the minimum
for an electrical conductor, i.e., 61 percent of IACS. The wire is
then annealed or partially annealed to obtain a desired tensile
strength and cooled. At the conclusion of the annealing operation,
it is found that the annealed alloy wire has the properties of
acceptable conductivity and improved tensile strength together with
unexpectedly improved percent ultimate elongation and surprisingly
increased bendability and fatigue resistance as specified
previously in this application. The annealing operation may be
continuous as in resistance annealing, induction annealing,
convection annealing by continuous furnaces or radiation annealing
by continuous furnaces, or, preferably, may be batch annealed in a
batch furnace. When continuously annealing, temperatures of about
450.degree. to about 1,200.degree. F may be employed with annealing
times of about 5 minutes to about one ten-thousandths of a minute.
Generally, however, continuous annealing temperatures and times may
be adjusted to meet the requirements of the particular overall
processing operation so long as the desired tensile strength is
achieved. In a batch annealing operation, a temperature of
approximately 400.degree. to about 750.degree. F is employed with
residence times of about 30 minutes to about 24 hours. As mentioned
with respect to continuous annealing, in batch annealing the times
and temperatures may be varied to suit the overall process so long
as the desired tensile strength is obtained. Simply by way of
example, it has been found that the following tensile strengths in
the present aluminum wire are achieved with the listed batch
annealing temperatures and times.
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TABLE I
Tensile Strength Temperature Time
__________________________________________________________________________
12,000 to 14,000 650.degree.F 3 hours 14,000 to 15,000 550.degree.F
3 hours 15,000 to 17,000 520.degree.F 3 hours 17,000 to 22,000
480.degree.F 3 hours
__________________________________________________________________________
During the continuous casting of this alloy, a substantial portion
of the iron present in the alloy precipitates out of solution as
iron aluminate intermetallic compound (FeAl.sub.3). Thus, after
casting, the bar contains a dispersion of FeAl.sub.3 in a
supersaturated solid solution matrix. The supersaturated matrix may
contain as much as 0.17 weight percent iron. As the bar is rolled
in a hot-working operation immediately after casting, the
FeAl.sub.3 particles are broken up and dispersed throughout the
matrix inhibiting large cell formation. When the rod is then drawn
to its final gauge size without intermediate anneals and then aged
in a final annealing operation, the tensile strength, elongation
and bendability are increased due to the small cell size and the
additional pinning of dislocations by preferential precipitation of
FeAl.sub.3 on the dislocation sites. Therefore, new dislocation
sources must be activated under the applied stress of the drawing
operation and this causes both the strength and the elongation to
be further improved.
The properties of the present aluminum alloy wire are significantly
affected by the size of the FeAl.sub.3 particles in the matrix.
Coarse precipitates reduce the percent elongation and bendability
of the wire by enhancing nucleation and thus, formation of large
cells which, in turn, lowers the recrystallization temperature of
the wire. Fine precipitates improve the percent elongation and
bendability by reducing nucleation and increasing the
recrystallization temperature. Grossly coarse precipitates of
FeAl.sub.3 cause the wire to become brittle and generally unusable.
Coarse precipitates have a particle size of above 2,000 angstrom
units and fine precipitates have a particle size of below 2,000
angstrom units.
A typical alloy No. 12 AWG wire of the present invention has
physical properties of 15,000 p.s.i. tensile strength, ultimate
elongation of 20 percent, conductivity of 61 percent IACS, and
bendability of 20 bends to break. Ranges of physical properties
generally provided by No. 12 AWG wire prepared from the present
alloy include tensile strengths of about 12,000 to about 22,000
p.s.i., ultimate elongations of about 40 to about 5 percent,
conductivities of about 61 to about 63 percent and number of bends
to break of about 45 to 10.
A more complete understanding of the invention will be obtained
from the following examples.
EXAMPLE NO. 1
A comparison between prior EC aluminum alloy wire and the present
aluminum alloy wire is provided by preparing a prior EC alloy with
aluminum content of 99.73 weight percent, iron content of 0.18
weight percent, silicon content of 0.059 weight percent, and trace
amounts of typical impurities. The present alloy is prepared with
aluminum content of 99.45 weight percent, iron content of 0.45
weight percent, silicon content of 0.056 weight percent, and trace
amounts of typical impurities. Both alloys are continuously cast
into continuous bars and hot-rolled into continuous rod in similar
fashion. The alloys are then cold-drawn through successively
constricted dies to yield No. 12 AWG continuous wire. Sections of
the wire are collected on separate bobbins and batch
furnace-annealed at various temperatures and for various lengths of
time to yield sections of the prior EC alloy and the present alloy
of varying tensile strengths. Several samples of each section are
tested in a device designed to measure the number of bends required
to break each sample at a particular flexure point. Through uniform
force and tension, the device fatigues each sample through an arc
of approximately 135.degree.. The wire is bent across a pair of
spaced opposed mandrels having a diameter equal to that of the
wire. The mandrels are spaced apart a distance of about 11/2 times
the diameter of the wire. One bend is recorded after the wire is
deflected from a vertical disposition to one extreme of the arc,
returned back to vertical, deflected to the opposite extreme of the
arc, and returned back to the original vertical disposition. The
speed of deflection, force and tension are substantially equal for
all tested samples. The results are as follows:
---------------------------------------------------------------------------
TABLE IIA
EC Alloy Present Alloy Tensile No. of Bends Tensile Average No. of
Strength to Break Strength Bends to Break
__________________________________________________________________________
10,083 431/2 13,500 44 12,788 24 14,300 43 13,480 211/2 15,100 36
14,168 14 16,025 291/2 15,200 133/4 17,050 25 16,100 11 17,134 18
17,125 93/4 18,253 14 18,186 83/4 19,571 13 23,069 51/2 25,286 43/4
29,309 4 35,986 31/2
__________________________________________________________________________
As shown in Table IIA, the present alloy has a surprisingly
improved property of bendability over conventional EC alloy.
Several samples of the present alloy No. 12 AWG wire and EC alloy
No. 12 AWG wire, processed as previously specified, are then tested
for percent ultimate elongation by standard testing procedures. At
the instant of breakage, the increase in length of the wire is
measured. The percent ultimate elongation is then figured by
dividing the initial length of the wire sample into the increase in
length of the wire sample. The tensile strength of the wire sample
is recorded as the pounds per square inch of cross-sectional
diameter required to break the wire during the percent ultimate
elongation test. The results are as follows:
---------------------------------------------------------------------------
TABLE IIB
EC Alloy Present Alloy Tensile Percent Ultimate Tensile Percent
Ultimate Strength Elongation Strength Elongation
__________________________________________________________________________
13,500 30.8 % 10,000 30.5% 14,300 30 % 12,700 21 % 15,525 24 %
13,500 14 % 16,150 19 % 14,200 11.5% 16,550 16 % 15,000 8 % 17,200
13.2 % 16,500 3.5% 18,270 8.6 % 18,300 2 % 19,000 6.7 %
__________________________________________________________________________
As shown in Table IIB, the present alloy has a surprisingly
improved property of percent ultimate elongation over conventional
EC alloy.
EXAMPLES 2 THROUGH 7
Six aluminum alloys are prepared with varying amounts of major
constituents. Those alloys are reported in the following table:
---------------------------------------------------------------------------
TABLE III
Example No. % Al % Fe % Si
__________________________________________________________________________
2 99.73 0.180 0.059 3 99.52 0.385 0.063 4 99.46 0.450 0.056 5 99.36
0.540 0.064 6 99.275 0.650 0.015 7 99.20 0.750 0.030
__________________________________________________________________________
The six alloys are then cast into six continuous bars and
hot-rolled into six continuous rods. The rods are cold-drawn
through successively constricted dies to yield No. 12 gauge wire.
The wire produced from the alloys of examples No. 2 and 4 are
resistance annealed and the remainder of the examples are batch
furnace annealed to yield the tensile strengths reported in Table
IV. After annealing, each of the wires is tested for percent
conductivity, tensile strength, percent ultimate elongation and
average number of bends to break by standard testing procedures for
each, except that the procedure specified in Example No. 1 is used
for determining average number of bends to break. These results are
reported in the following table.
---------------------------------------------------------------------------
TABLE IV
Con- ductivity Tensile % Ultimate Average No. of Example No. in %
Strength Elongation Bends to Break IACS
__________________________________________________________________________
2 62.8 15,150 8.1 151/2 3 61.3 15,153 28.0 271/2 4 61.5 15,152 37.5
28 5 61.5 15,152 35.0 281/2 6 61.25 14,300 28.0 32 7 61.2 15,800 25
28
__________________________________________________________________________
from a review of these results, it may be seen that Example No. 2
falls outside the scope of the present invention in percentage of
components. In addition, it will be noted for Example No. 2 that
the percentage of ultimate elongation is somewhat lower than
desirable and the average number of bends to break the sample is
lower than the remaining examples.
EXAMPLE NO. 8
An aluminum alloy is prepared with an aluminum content of 99.42
weight percent, iron content of 0.50 weight percent, silicon
content of 0.055 weight percent and trace amounts of typical
impurities. The alloy is cast into a continuous bar which is
hot-rolled to yield a continuous rod. The rod is then cold-drawn
through successively constricted dies to yield No. 12 AWG wire. The
wire is collected on a 30 inch bobbin until the collected wire
weighs approximately 250 pounds. The bobbin is then placed in a
cold General Electric Bell Furnace and the temperature therein is
raised to 480.degree. F. The temperature of the furnace is held at
480.degree. F for 3 hours after which the heat is terminated and
the furnace cools to 400.degree. F. The furnace is then quick
cooled and the bobbin is removed. Under testing, it is found that
the alloy wire has a conductivity of 61.6 percent IACS, a tensile
strength of 16,500 p.s.i., a percentage of ultimate elongation of
20 percent, and a number of bends to break of 18.
EXAMPLE NO. 9
Example 8 is repeated except the Bell Furnace temperature is raised
to 500.degree. F and held for 3 hours prior to cooling. The
annealed alloy wire has a conductivity of 61.4% IACS, a tensile
strength of 15,000 p.s.i., a percentage of ultimate elongation of
27 percent, and a number of bends to break of 28.
EXAMPLE NO. 10
Example No. 8 is repeated except the Bell Furnace temperature is
raised to 600.degree. F. and held for three hours prior to cooling.
The annealed alloy wire has a conductivity of 61.2 percent IACS, a
tensile strength of 14,000 p.s.i., a percentage of elongation of 30
percent, and a number of bends to break of 43.
EXAMPLE NO. 11
Example No. 8 is repeated except the Bell Furnace temperature is
raised to 600.degree. F and held 11/2 hours prior to cooling. The
annealed alloy has a conductivity of 61.5 percent IACS, a tensile
strength of 16,000 p.s.i., a percentage of elongation of 22
percent, and a number of bends to break of 23.
EXAMPLE NO. 12
The alloy of Example No.8 is cast into a continuous bar which is
hot-rolled to yield a continuous f temper rod of 3/8 inch diameter.
The rod is then cold-drawn through successively constricted dies to
yield No. 14 AWG wire. The wire is then redrawn on a Synchro Model
BG-16 wire drawing machine which includes a Synchro Resistioneal
continuous in line annealer. The wire is drawn to No. 28 AWG at a
finishing speed of 3,300 feet per minute and the in line annealer
is operated at 52 volts with a transformer tap setting at No. 8.
The annealed alloy wire has a conductivity of 62 percent IACS, a
tensile strength of 15,450 p.s.i., and a percentage of ultimate
elongation of 25 percent. Since the wire gauge is so small, the
number of bends to break is extremely large.
EXAMPLE NO. 13
The alloy of Example No. 8 is cast into a continuous bar which is
hot-rolled to yield a continuous f temper rod of 3/8 inch diameter.
The rod is then cold-drawn on a Synchro Style No. F X 13 wire
drawing machine which includes a continuous in line annealer. The
rod is drawn to No. 12 AWG wire at a finishing speed of 2,000 feet
per minute and the in line annealer voltage at preheater No. 1 is
35 volts, at preheater No. 2 is 35 volts, and at the annealer is 22
volts. The three transformer taps are set at No. 5. The annealed
alloy wire has a conductivity of 62 percent IACS, a tensile
strength of 16,300 p.s.i., and a percentage of ultimate elongation
of 20 percent.
For the purpose of clarity, the following terminology used in this
application is explained as follows:
Rod -- A solid product that is long in relation to its
cross-section. Rod normally has a cross-section of between 3 inches
and 0.375 inch.
Wire -- A solid wrought product that is long in relation to its
cross-section, which is square or rectangular with sharp or rounded
corners or edges, or is round, a regular hexagon or a regular
octagon, and whose diameter or greatest perpendicular distance
between parallel faces is between 0.374 inches and 0.0031 inch.
While this invention has been described in detail with particular
reference to preferred embodiments thereof, it will be understood
that variations and modifications can be effected within the spirit
and scope of the invention as described hereinbefore and as defined
in the appended claims.
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