Aluminum alloy electrical conductor and method for making same

Abstract

Aluminum alloy wire and other articles are produced from aluminum base alloys containing from about 0.35% to 4% by weight Cobalt, up to about 2.5% of additional alloying elements, and from about 93.50% to about 99.65% by weight aluminum. The alloy wire and other articles have unexpectedly improved physical properties.

Parent Case Text

This is a continuation of application Ser. No. 199,729, filed 11-17-71, now abandoned, which in turn is a division of application Ser. No. 54,563 filed July 13, 1970, now abandoned.

Description

The present invention concerns an aluminum base alloy especially suited for producing high strength lightweight products including wire, rod and other articles of manufacture. The present alloy is particularly well suited for use as a wire or cable for conducting electricity.

It is an object of the present invention to provide a new aluminum base alloy with improved properties or an improved combination of properties selected from yield strength, ultimate tensile strength, percent ultimate elongation, ductility, fatigue resistance and creep resistance as compared to conventional aluminum alloys of similar electrical properties. It has been found that the present alloy yields products with a brighter metal finish than that obtained with conventional alloys. This and other objects, features and advantages of the present invention will be apparent from a consideration of the following detailed description of one embodiment of the invention.

The present invention will be disclosed by reference to an aluminum alloy, electrically conductive, wire and a method for its preparation. It should be understood, however, that the present alloy may find uses in other articles of manufacture.

In accordance with the invention, the present aluminum base alloy is prepared by mixing Cobalt and optionally other alloying elements with aluminum in a furnace to obtain a melt having requisite percentages of elements. It has been found that suitable results are obtained with Cobalt being present in a weight percentage of about 0.35% to about 4%. Superior results are achieved when Cobalt is present in a weight percentage of 0.45% to about 2% and particularly superior and preferred results are obtained when Cobalt is present in a percentage by weight of about 0.50 to about 1.50%.

The aluminum content of the present alloy may vary from about 93.50 to about 99.65% by weight with superior results being obtained when the aluminum content varies between 96.25 and 99.45% by weight. Particularly superior and preferred results are achieved when the aluminum content varies between 97.0% and 99.40% by weight. If commercial aluminum is employed in preparing the present melt, it is preferred that the aluminum, prior to adding to melt in the furnace, contain no more 0.1% total of trace impurities.

Optionally the present alloy may contain an additional alloying element or group of alloying elements. The total concentration of the optional alloying elements may be up to 2.50% by weight; preferably from about 0.1% to about 1.75% by weight is employed. Particularly superior and preferred results are obtained when 0.1% to about 1.5% by weight of total additional alloying elements is employed. Additional alloying elements include the following:

ADDITIONAL ALLOYING ELEMENTS ______________________________________ Magnesium Yttrium Dysprosium Iron Scandium Terbium Nickel Thorium Erbium Copper Tin Neodymium Silicon Molybdenum Indium Zirconium Zinc Boron Cerium Tungsten Thallium Niobium Chromium Rubidium Hafnius Bismuth Titanium Lanthanum Antimony Carbon Tantalum Vanadium Cesium Rhenium ______________________________________

Particularly superior and preferred results are obtained with the following additional alloying elements in the percentages, by weight, as shown:

PREFERRED ADDITIONAL ALLOYING ELEMENTS ______________________________________ Magnesium 0.01 to 1.0 % Iron 0.1 to 2.50% Nickel 0.05 to 2.50% Copper 0.05 to 2.50% Silicon 0.05 to 1.0 % Zirconium 0.01 to 1.0 % Niobium 0.01 to 2.0 % Tantalum 0.01 to 2.0 % Yttrium 0.01 to 1.0 % Scandium 0.01 to 1.0 % Thorium 0.01 to 1.0 % Rare Earth Metals 0.01 to 2.50 % Carbon 0.01 to 1.0 % ______________________________________

The rare earth metals may be present either individually within the percentage range or as a partial or total group, the total percentage of the group being within the percentage range.

It should be understood that the additional alloying elements may be present either individually or as a group of two or more of the elements. It should be understood, however, that if two or more of the additional alloying elements are employed, the total concentration of additional alloying elements should not exceed 2.50% by weight.

After preparing the melt, the aluminum alloy may be continuously cast into a continuous bar by a continuous casting machine and then, substantially immediately thereafter, hot-worked in a rolling mill to yield a continuous aluminum alloy rod.

One example of a continuous casting and rolling operation capable of producing continuous rod as specified in this application is contained in the following paragraphs. It should be understood that other methods of preparation may be employed. Such other methods include conventional extrusion and hydrostatic extrusion to obtain rod or wire directly, sintering an aluminum alloy powder to obtain rod or wire directly, casting rod or wire directly from a molten aluminum alloy, and conventional casting of aluminum alloy billets which are subsequently hot-worked to rod and drawn into wire.

CONTINUOUS CASTING AND ROLLING OPERATION

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 in its periphery which is 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 function 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 low conductivity. 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 improved tensile strength and yield strength together with unexpectedly improved percent ultimate elongation and surprisingly increased ductility 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 1/10,000 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.

It has been found that the properties of a Number 10 gauge (American wire gauge) soft wire of the present alloy vary between the following figures:

Tensile % Yield Conductivity Strength, psi. Elongation Strength, psi. ______________________________________ 50% - 63+% 12,000-24,000 12% - 30% 8,000-18,000 ______________________________________

A more complete understanding of the invention will be obtained from the following examples:

EXAMPLE NO. 1

Various melts are prepared by adding the required amount of alloying elements to 1816 grams of molten aluminum, containing less than 0.1% trace element impurities, to achieve a percentage concentration of elements as shown; the remainder being aluminum. Graphite crucibles are used except in those cases where the alloying elements are known carbide formers, in which cases aluminum oxide crucibles are used. The melts are held for sufficient times and at sufficient temperatures to allow complete solubility of the alloying element or elements with the base aluminum. An argon atmosphere is provided over the melt to prevent oxidation. Each melt is continuously cast on a continuous casting machine and immediately hot-rolled through a rolling mill to 3/8 inch continuous rod. Wire is then drawn from the rod in both the as-rolled condition (hard rod) and after being annealed for five hours at 650.degree.F (soft rod). The final wire diameter obtained is 0.107 inches, 10 gauge AWG. Wire from each type rod is tested in both the as-drawn condition (hard wire) and after being annealed for five hours at 650.degree.F (soft wire).

The types of alloys employed and the results of the tests performed thereon are as follows: n

TABLE 1 __________________________________________________________________________ CO Fe Mg Ni HR SR HW-HR HW-SR SW-HR SW-SR Properties __________________________________________________________________________ .10 3.4 33.7 1.2 1.7 37.5 34.5 % Elong. .10 19,575 11,137 27,735 23,900 12,100 11,290 UTS .10 62.75 63.34 62.42 63.14 62.25 63.23 % __________________________________________________________________________ IACS .80 .80 .08 2.1 25.5 2.0 2.5 17.8 24.5 31,450 19,400 38,040 34,045 19,790 18,978 58.38 59.63 58.03 58.79 59.76 59.98 __________________________________________________________________________ .80 .08 .80 2.1 27.5 1.7 25.1 29,400 15,900 34,700 15,870 62.62 60.06 59.56 60.47 __________________________________________________________________________ .60 3.9 33.2 1.7 2.0 29.2 31.5 23,265 13,341 31,249 28,280 14,865 13,000 62.19 62.43 61,70 62.20 62.83 62.38 __________________________________________________________________________ .80 4.7 25.0 2.5 2.4 30.1 31.8 25,215 15,272 31,886 30,580 16,445 15,090 60.92 60.66 60.96 61.45 62.0 61.53 __________________________________________________________________________ 1.0 3.8 33.2 2.0 1.3 33.0 27.7 23,953 14,933 31,832 28,912 16,100 14,300 62.38 62.11 61.22 61.53 62.19 61.93 __________________________________________________________________________ .80 .80 4.3 22.0 3.0 3.0 21.0 22.0 27,800 18,340 31,700 27,450 17,590 15,750 59.01 61.42 58.37 59.88 60.48 60.63 __________________________________________________________________________ 1.0 .80 3.3 20.1 4.2 2.3 25.0 27.7 28,150 17,875 32,135 26,685 17,200 16,275 58.58 59.90 58.37 59.29 59.86 60.06 __________________________________________________________________________ .80 .80 .10 1.1 14.5 3.4 2.0 20.5 24.5 34,395 19,650 40,360 36,700 20,280 19,240 57.56 59.38 56.80 58.07 59.02 59.33 __________________________________________________________________________ .40 .80 .10 .40 2.8 20.0 2.0 2.5 22.9 24.5 30,340 17,110 37,935 32,500 18,350 17,245 59.19 60.65 58.64 59.66 60.65 60.72 __________________________________________________________________________ .30 .10 .90 1.2 21.0 2.2 2.3 22.7 23.0 29,400 16,040 40,530 33,300 17,450 16,700 59.34 59.75 58.14 58.81 59.95 60.01 __________________________________________________________________________ .80 .10 3.2 19.4 2.0 2.0 21.5 26.1 28,650 16.720 41,200 34,580 18,250 16,390 59.89 60.32 59.32 59.93 60.99 60.80 __________________________________________________________________________ HR = Hard Rod SR = Soft Rod HW-HR = Hard wire drawn from Hard Rod HW-SR = Hard Wire drawn from Soft Rod SW-HR = Soft Wire drawn from Hard Rod SW-SR = Soft Wire drawn from Soft Rod % Elong. = Percent ultimate elongation UTS = Ultimate Tensile Strength % IACS = Conductivity in Percentage IACS Soft wire and soft rod are the fully annealed forms of the products.

EXAMPLE NO. 2

An additional alloy melt is prepared according to Example No. 1 so that the composition is as follows in weight percent: Cobalt 0.60% Iron 1.10% Magnesium 0.15% Aluminum Remainder

The melt is processed to a No. 10 gauge soft wire from hard rod. The physical properties of the wire are as follows:

Ultimate Tensile Strength 21,440 psi Percent Ultimate Elongation 18.50% Conductivity 58.05% IACS

EXAMPLE NO. 3

An additional alloy melt is prepared according to Example No. 1 so that the composition is as follows in weight percent:

Cobalt 0.80% Misch Metal 1.0% Aluminum Remainder

Misch metal is a commercial designation for a blend of rare earth metals and Thorium obtained during the processing of Thorium metal.

The melt is processed to a No. 10 gauge soft wire from hard rod. The physical properties of the wire are as follows:

Ultimate Tensile Strength 18,000 psi Percent Ultimate Elongation 20% Conductivity 59.2% IACS

EXAMPLE NO. 4

An additional alloy melt is prepared according to Example No. 1 so that the composition is as follows in weight percent:

Cobalt 0.80% Niobium 0.30% Tantalum 0.30% Aluminum Remainder

The melt is processed to a No. 10 gauge soft wire from hard rod. The physical properties of the wire are as follows:

Ultimate Tensile Strength 19,280 psi Percent Ultimate Elongation 20% Conductivity 58.6 IACS

EXAMPLE NO. 5

An additional alloy melt is prepared according to Example No. 1 so that the composition is as follows in weight percent:

Cobalt 0.80% Copper 0.40% Silicon 0.30% Aluminum Remainder

The melt is processed to a No. 10 gauge soft wire from hard rod. The physical properties of the wire are as follows:

Ultimate Tensile Strength 16,700 psi Percent Ultimate Elongation 19.5% Conductivity 59.8% IACS

EXAMPLE NO. 6

An additional alloy melt is prepared according to Example No. 1 so that the composition is as follows in weight percent:

Cobalt 0.80% Zirconium 0.60% Aluminum Remainder

The melt is processed to a No. 10 gauge soft wire from hard rod. The physical properties of the wire are as follows:

Ultimate Tensile Strength 18,300 psi Percent Ultimate Elongation 19.5% Conductivity 58.6% IACS

ADDITIONAL EXAMPLES

Additional alloy melts are prepared according to Example No. 1. The composition and the physical properties of No. 10 gauge soft wire from hard rod of the alloy melts are as follows:

TABLE 2 __________________________________________________________________________ % % IACS Example No. Co Fe Mg UTS in psi Elongation Conductivity __________________________________________________________________________ 1171 1.0 -- -- 16,420 26.6 61.28 1172 1.2 -- -- 16,355 28.8 61.00 1174 .8 -- .1 17,615 27.3 60.71 1175 .8 -- .15 17,480 24.7 60.68 1176 .8 .5 -- 17,430 24.7 60.68 1177 .8 .5 .1 17,410 24.8 60.43 1180 .6 -- .19 16,910 25.8 60.60 1181 .6 -- .24 17,830 26.8 60.32 1182 .7 -- .21 17,845 25.7 60.27 1183 .8 .3 -- 17,785 26.6 61.65 1184 .8 .5 -- 17,700 28.0 61.54 1185 .6 .9 -- 18,485 23.7 60.76 1186 .8 .9 -- 17,930 26.5 59.97 1187 .4 1.1 -- 19,355 19.8 60.19 1188 .6 1.1 -- 20,400 17.5 59.87 1196 .2 1.1 -- 18,515 20.5 60.41 1197 .4 .9 -- 17,495 22.4 60.40 1198 .4 1.1 -- 18,695 21.5 60.02 1199 .6 .9 -- 18,975 20.3 60.99 1200 .2 .7 .1 17,775 22.8 60.83 1201 .6 .9 .1 20,898 20.7 59.15 1215 .8 -- .05 17,010 29.5 61.61 1216 .8 Graphite .05 17,635 27.3 61.84 .01 1218 .8 -- .1 18,260 25.0 60.90 1219 .8 .53 -- 17,180 29.2 61.62 1220 .8 .4 -- 17,480 29.0 61.31 1221 .8 .5 .051 18,965 26.4 61.28 1223 1.4 -- -- 16,050 31.0 61.55 1224 .8 Graphite .075 17,745 22.5 61.35 .1 1227 .8 .5 .05 18,785 17.1 60.72 1228 .8 .5 .2 17,140 27.2 60.56 1231 .8 -- .05 17,100 23.3 61.45 1233 .8 -- .1 17,621 25.3 60.96 1235 .8 -- .15 18,420 25.7 60.49 1237 .7 .5 -- 17,030 24.5 61.49 1238 .8 .7 -- 17,295 26.4 60.96 1239 .6 .5 .05 17,975 22.7 61.29 1240 .8 .3 .05 17,630 23.3 61.25 1271 .77 -- .19 18,800 23.5 59.87 1265 .89 -- .13 18,926 18.5 60.07 1293 1.40 .49 -- 17,120 24.5 59.52 1313 .20 1.10 .12 17,400 24.2 60.01 1316 .22 .96 .15 17,425 22.0 59.92 1317 .23 1.20 .14 18,333 23.7 59.47 1321 .43 .70 .054 17,200 26.5 61.12 1322 .40 1.05 .05 17,830 22.0 60.12 1325 .40 .68 .10 17,792 25.5 60.44 1326 .42 .84 .98 18,248 23.7 60.22 1327 .38 1.10 .11 19,004 25.2 59.52 1328 .42 .35 .15 17,000 24.0 60.88 1329 .41 .50 .16 17,000 24.0 60.47 1330 .44 .70 .16 18,100 25.0 59.80 1331 .42 .91 .16 18,690 22.0 60.51 1343 .33 .95 Ni.54 20,875 16.4 49.90 1.Hf 1355 .62 1.10 .15 20,990 12.5 58.05 __________________________________________________________________________

Through testing and analysis of an alloy containing 0.80 Cobalt and the remainder Aluminum, it has been found that the present aluminum base alloy after cold working includes an intermetallic compound precipitate. The compound is identified as Cobalt aluminate (Co.sub.2 Al.sub.9). This intermetallic compound is found to be very stable and especially so at high temperatures. The compound also has a low tendency to coalesce during annealing of products formed from the alloy and the compound is generally incoherent with the aluminum matrix. The mechanism of strengthening for this alloy is in part due to the dispersion of the intermetallic compound as a precipitate throughout the aluminum matrix. The precipitate tends to pin dislocation sites which are created during cold working of products formed from the alloy. Upon examination of the intermetallic compound precipitate in a cold drawn product, it is found that the precipitates are oriented in the direction of drawing. In addition, it found, when examining a No. 10 gauge wire, that the precipitates are rod-like in configuration and a majority are one-fourth to one-half microns long and about one-eighth micron in diameter. The precipitates may also be spherical or plate-like. The cell size in this tested sample of wire is approximately 1/2 to 1 micron in cross-section.

Other intermetallic compounds may also be formed depending upon the constituents of the melt and the relative concentrations of the alloying elements. Those intermetallic compounds include the following: NiAl.sub.3, Ni.sub.2 Al.sub.3, NgCoAl, FeAl.sub.3, Fe.sub.2 Al.sub.5, Co.sub.4 Al.sub.13, CeAl.sub.4, CeAl.sub.2, VAl.sub.11, VAl.sub.7, VAl.sub.6, VAl.sub.3, WAl.sub.12, Zr.sub.3 Al, Zr.sub.2 Al, LaAl.sub.4, LaAl.sub.2.

For the purpose of clarity, the following terminology used in this application is explained as follows:

Aluminum alloy rod product -- A solid product that is long in relation to its cross-section. Rod normally has a cross-section of between three inches and 0.375 inches.

Aluminum alloy wire product -- 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 inches.

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.

Claims

We claim:

1. Aluminum alloy electrical conductor having a minimum conductivity of 58% IACS consisting essentially of from about 0.35 to about 4.0 weight percent cobalt, from about 0.1 to about 2.5 weight percent iron, the remainder being aluminum with associated trace elements, said aluminum alloy electrical conductor having the following properties when measured as a No. 10 A.W.G. fully annealed wire: Tensile strength 12,000 - 24,000 psi Elongation: 12% - 30% Yield strength: 8,000 - 18,000 psi.

2. The aluminum alloy electrical conductor according to claim 1 further including an additional alloying element selected from the group consisting of magnesium, copper, silicon, zirconium, niobium, tantalum, yttrium, scandium, thorium, carbon, rare earth metals, and mixtures thereof, the combined weight percentage of said additional alloying elements not to exceed about 1.75 weight percent.

3. The aluminum alloy electrical conductor according to claim 1 hwerein the aluminum content ranges from about 93.5 to about 99.45 weight percent.

4. The aluminum alloy electrical conductor according to claim 1 wherein the weight percentage of cobalt ranges from 0.45 to about 2%, the weight percentage of iron ranges from 0.1 to about 1.5%.

5. The aluminum alloy electrical conductor according to claim 1 including an additional alloying element selected from the group consisting of magnesium, copper, silicon, and mixtures thereof, the combined weight percentage of alloying elements not exceeding about 1%.

6. The aluminum alloy electrical conductor according to claim 5 includes magnesium as an additional alloying element in an amount up to about 0.16 weight percent.

7. The aluminum alloy electrical conductor according to claim 5 wherein the additional alloying element is copper in an amount up to about 0.40 weight percent.

8. The aluminum alloy electrical conductor according to claim 5 wherein the additional alloying element is silicon in an amount up to about 0.30 weight percent.

9. The aluminum alloy electrical conductor according to claim 1 wherein cobalt is present in a weight percentage of from about 0.50 to about 1.5%.

10. The aluminum alloy electrical conductor according to claim 1 consisting essentially of about 0.8% by weight cobalt and about 0.8% by weight iron.

11. The aluminum alloy electrical conductor according to claim 5 wherein the weight percentages of the constituents are as follows:

12. The aluminum alloy electrical conductor according to claim 5 wherein the weight percentages of the constituents are as follows:

13. Aluminum alloy electrical conductor having a minimum conductivity of 58% IACS consisting essentially of from about 0.35 to about 4.0 weight percent cobalt, from about 0.1 to about 2.5 weight percent iron, the remainder being aluminum with associated trace elements, said aluminum alloy electrical conductor having the following properties when measured as a fully annealed wire:

14. The aluminum alloy electrical conductor according to claim 13 wherein said conductor is in the form of a rod.

15. The aluminum alloy electrical conductor according to claim 13 wherein said conductor is in the form of a wire.

16. The aluminum alloy electrical conductor according to claim 3 further including an additional alloying element selected from the group consisting of magnesium, copper, silicon and mixtures thereof; the combined weight percentage of the additional alloying elements not to exceed about 1.75% weight percentage.

17. The aluminum alloy electrical conductor according to claim 13 wherein the weight percentage of cobalt ranges from 0.45 to about 2% and the weight percentage of iron ranges from 0.1 to about 1.5%.

18. The aluminum alloy electrical conductor according to claim 16 wherein the weight percentages of the constituents are as follows:

19. The aluminum alloy electrical conductor according to claim 16 wherein the weight percentages of the constituents are as follows:

20. The aluminum alloy electrical conductor according to claim 13 wherein cobalt is present in a weight percentage of from about 0.50 to about 1.5%.

21. The aluminum alloy electrical conductor according to claim 13 consisting essentially of about 0.8% by weight cobalt and about 0.8% by weight iron.

22. Method of preparing an aluminum alloy conductor having a minimum conductivity of at least 58% IACS comprising the steps of:

A. alloying from about 0.35 to about 4.0 weight percent cobalt with about 0.1 to about 2.5 weight percent iron, the remainder being aluminum with associated trace elements;

B. casting the alloy in a moving mold formed between a groove in the periphery of a rotating casting wheel and a metal belt lying adjacent said groove for a portion of its length;

C. hot rolling the cast alloy substantially immediately after casting while the cast alloy is in substantially that condition as cast to form a continuous rod;

said aluminum alloy conductor having the following properties as a fully annealed wire:

23. The method in according to claim 22 including the further step of drawing said conductor through wire-drawing dies, without annealing the conductor between drawing dies, to form wire.

24. The method according to claim 22 wherein the alloying step also includes the addition of alloying elements selected from the group consisting of magnesium, copper, silicon and mixtures thereof, in amounts sufficient to yield said alloy wherein the combined weight percentage of the additional alloying elements not to exceed about 1.75 weight percent.

25. The method according to claim 22 wherein the alloying step comprises the addition of cobalt and iron to yield an alloy consisting essentially of about 0.8% by weight cobalt and about 0.8% by weight iron.

26. The method according to claim 22 wherein magnesium is added as an additional alloying element to yield an alloy having the following weight percentages:

27. The method according to claim 22 wherein magnesium is added as an additional alloying element to yield an alloy having the following weight percentages:

28. The method according to claim 23 wherein said wire has the following properties when measured as a No. 10 A.W.G. fully annealed wire: