EP3540745A1 - Electrical transport wire in aluminium alloy with high electrical conductivity - Google Patents

Abstract

The invention relates to an electrical wire made of aluminum alloy, comprising aluminum, zirconium and unavoidable impurities, characterized in that said alloy comprises at least 80 parts by weight of zirconium in the form of precipitates (AlZr) per 100 parts by weight of zirconium in said alloy.

Description

The invention relates to an electrical cable comprising at least one aluminum alloy electrical transport wire, a method of manufacturing said electric transport wire, and a method of manufacturing said electric cable.

It typically, but not exclusively, applies to high voltage electrical transmission cables or overhead power transmission cables, well known under the Anglicism " Overhead Lines (OHL) cable ".

These cables are conventionally composed of a central reinforcing element, surrounded by at least one electrically conductive layer.

The central reinforcing element may be a composite or metallic element. By way of example, mention may be made of steel strands or composite strands of aluminum in an organic matrix.

The electrically conductive layer can in turn typically comprise an assembly of metal strands, preferably twisted around the central element. The metal strands may be strands of aluminum, copper, aluminum alloy or copper alloy. That said, the electrically conductive layer is generally made of aluminum or an aluminum alloy, since this material has a relatively low weight compared to other electrically conductive materials.

Of the document EP 0 787 811 is known an electric transport wire aluminum alloy ensuring good breaking strength, and good temperature resistance. This alloy contains 0.28 to 0.80 percent by weight of zirconium, 0.10 to 0.80 percent by weight of manganese and 0.10 to 0.40 percent by weight of copper. This alloy is obtained by a process comprising a casting step of the molten aluminum alloy, then an extrusion or rolling step, then a heating step, and finally a cold working step in order to obtain alloy wires 4 mm in diameter. The heating step can be performed after the cold working step.

However, this alloy has the disadvantage of having an electrical conductivity lower than 56.5% IACS ( International Annealed Copper Standard ), less than 51% IACS depending on the operating conditions used. Furthermore, the method of manufacturing said alloy does not allow on the one hand to control the microstructure of zirconium precipitates (Al ₃ Zr), and on the other hand to produce sufficient zirconium precipitates in said alloy. As a result, this method induces a breaking strength and an electrical conductivity of said alloy which are not optimized.

The object of the present invention is to overcome the disadvantages of the techniques of the prior art by proposing an aluminum alloy, in particular used as an electric transport wire in an electric cable, comprising aluminum and zirconium, easy to manufacture, having improved electrical properties (in terms of electrical capacity and electrical conductivity), while ensuring good mechanical properties, especially in terms of breaking strength and resistance to hot creep and good temperature resistance.

To do this, the present invention firstly relates to an electric aluminum alloy wire comprising aluminum, zirconium and unavoidable impurities, characterized in that said alloy comprises at least 80 parts by weight of zirconium under form of precipitates (Al ₃ Zr) per 100 parts by weight of zirconium in said aluminum alloy.

Thanks to the presence of at least 80 parts by weight of zirconium in the form of precipitates (Al ₃ Zr) per 100 parts by weight of zirconium in said aluminum alloy, the aluminum alloy of the electrical transport wire of the The invention has a higher electrical conductivity than prior art aluminum alloys while ensuring good electrical properties.

In a particular embodiment, said electric transport wire comprises at the surface a porous layer of alumina hydroxide.

In the invention, the alumina hydroxide layer is an aluminum oxide hydroxide layer, or in other words, a hydrated alumina layer.

Thanks to the porous layer of alumina hydroxide, the thermal emissivity is optimized and the thermal absorption is minimized, which is favorable to a significant reduction in the heating of the transport wire. electric that could be weakened at high temperatures.

The second subject of the present invention is an electric transport wire made of aluminum alloy comprising aluminum, zirconium precipitates and unavoidable impurities, characterized in that the said electric transport wire comprises at the surface a porous layer of hydroxide alumina.

Thanks to the porous layer of alumina hydroxide, the thermal emissivity is optimized and the thermal absorption is minimized, which is favorable to a significant reduction in the heating of the electric transport wire which could be embrittled at high temperatures. and thus to the improvement of electrical properties while guaranteeing good mechanical properties.

In a particular embodiment, said alloy comprises at least 80 parts by weight of zirconium in the form of precipitates (Al ₃ Zr) per 100 parts by weight of zirconium in said aluminum alloy.

Thanks to the presence of at least 80 parts by weight of zirconium in the form of precipitates (Al ₃ Zr) per 100 parts by weight of zirconium in said aluminum alloy, the aluminum alloy of the electric transport wire conforming to The second object of the invention has a higher electrical conductivity than aluminum alloys of the prior art.

In a particular embodiment, the aluminum alloy electrical transport wire according to the first object or the second subject of the invention is an electric transport wire made of said aluminum alloy.

According to a first variant of the first object or the second subject of the invention, the hydrated alumina layer is a monohydrated layer.

By way of example, mention may be made, as alumina monohydrate, of boehmite, which is the gamma polymorph of AlO (OH) or Al ₂ O ₃ .H ₂ O; or diaspore, which is the alpha polymorph of AlO (OH) or Al ₂ O ₃ .H ₂ O.

According to a second variant of the first object or the second subject of the invention, the hydrated alumina layer is a polyhydrated layer, and preferably a trihydrate layer.

By way of example, mention may be made, as alumina trihydrate, of gibbsite or hydrargillite, which is the gamma polymorph of Al (OH) ₃ ; the bayerite that is the alpha polymorph of Al (OH) ₃ ; or nordstrandite, which is the beta polymorph of Al (OH) ₃ .

In a particular embodiment of the first object or the second subject of the invention, the electric transport wire comprises a controlled microstructure dispersion of zirconium precipitates (Al ₃ Zr).

Thanks to the controlled microstructure dispersion of zirconium precipitates (Al ₃ Zr), the mechanical and thermal properties of the aluminum alloy and thus the electric transport wire are improved.

In the electrical transport wire according to the first object or the second subject of the invention, the aluminum alloy may comprise from 0.05% to 0.6% by weight of zirconium, preferably from 0.05% to 0.5% by weight of zirconium, and more preferably from 0.2% to 0.5% by weight of zirconium.

When the amount of zirconium in said aluminum alloy is less than 0.05% by weight, the aluminum alloy may not include enough zirconium precipitates, inducing a random distribution of said precipitates in the alloy and thus, a decrease in its electrical conductivity. When the amount of zirconium in said aluminum alloy is greater than 0.5% by weight, large zirconium precipitates (Al ₃ Zr) can be formed, inducing a decrease in the mechanical properties of the alloy, particularly in terms of Tear resistant.

In a particular embodiment, the diameter of the zirconium precipitates (Al ₃ Zr) in said alloy of the electric transport wire according to the first object or the second subject of the invention ranges from 1 to 100 nm, preferably from 1 to at 20 nm, and more preferably from 1 to 5 nm. As the diameter of the precipitates decreases, the temperature resistance of the alloy of the electrical transport wire of the invention is improved. Thus, the alloy of the electric transport wire according to the first object or object of the invention can withstand a temperature of 150 ° C, and preferably a temperature of 210 ° C.

In a particular embodiment, said zirconium precipitates (Al ₃ Zr) are spherical.

In a preferred embodiment, the aluminum alloy of the electrical transport wire conforms to the first object or second object of the invention further comprises a member selected from copper, iron and their mixture.

The presence of the iron in said aluminum alloy makes it possible to improve the mechanical properties with respect to the breaking strength, while maintaining a good electrical conductivity.

The aluminum alloy of the electric transport wire according to the first object or subject of the invention may comprise from 0.15% to 0.4% by weight of iron, and preferably from 0.25% to 0% by weight. 35% by weight of iron.

The presence of the copper in the aluminum alloy of the electric transport wire according to the first object or the second subject of the invention makes it possible to improve the mechanical properties with respect to the resistance to hot creep, while maintaining good electrical conductivity. An alloy having good creep resistance withstands deformation under long-term mechanical stresses at elevated temperatures.

The aluminum alloy of the electric transport wire according to the first object or subject of the invention may comprise from 0.05% to 0.35% by weight of copper, and preferably from 0.12% to 0%. 22% by weight of copper.

The electrical conductivity of the aluminum alloy of the electric transport wire according to the first object or subject of the invention may be at least 57% International Annealed Copper Standard (IACS), preferably at least 58%. % IACS, and preferably at least 59% IACS.

It is preferable that the aluminum alloy of the electrical transport wire according to the first object or object of the invention comprises only aluminum; zirconium; unavoidable impurities; and optionally an element selected from iron, copper and their mixture. Indeed, if we add other elements in the alloy, the electrical conductivity can drop sharply. For electrical applications, it is important to keep the aluminum alloy as pure as possible.

The aluminum content of the aluminum alloy of the electric transport wire according to the first object or second subject of the invention may be at least 95.00% by weight, preferably at least 98.00. % by weight, preferably at least 99.00% by weight, preferably at least 99.40%.

The unavoidable impurity content in the aluminum alloy of the electric transport wire according to the first object or subject of the invention may be at most 1.50% by weight, preferably at most 1, 10% by weight, preferably at most 0.60% by weight, preferably at most 0.30% by weight, and preferably at most 0.10% by weight.

In the present invention, the term "unavoidable impurities" means the sum of metallic or non-metallic elements included in the alloy, excluding aluminum, zirconium, iron, copper, and possibly oxygen, during the manufacture of said alloy.

These unavoidable impurities may be for example one or more of the following elements: Ag, Cd, Cr, Mg, Mn, Pb, Si, Ti, V, Ni, S, and / or Zn.

These unavoidable impurities are usually impurities intrinsic to aluminum.

In a particular embodiment, the aluminum alloy comprises at most 0.08% by weight, and preferably at most 0.05% by weight of Mn and / or Si. In fact, these unavoidable impurities can decrease the electrical conductivity of said alloy.

The third subject of the present invention is an electrical cable comprising at least one electric transport wire conforming to the first object or the second subject of the invention, characterized in that the said electric cable further comprises an elongated reinforcing element.

In the present invention, the presence of an elongate reinforcing element makes it possible in particular to form an aerial power transmission cable (i.e. OHL cable).

Preferably, the elongate reinforcing member is surrounded by said aluminum alloy electrical transport wire.

In a particular embodiment, the elongate reinforcing element is a central element.

The elongated reinforcing element is preferably a central mechanical support rod.

In the context of the invention, the term "aluminum alloy electrical transport wire according to the first object or second object of the invention", a "metal strand", or "an element electrically elongated driver ".

In a particularly preferred manner, the electric cable according to the third subject of the invention comprises an assembly (ie a plurality) of aluminum alloy electrical transport wires conforming to the first object or the second subject of the invention, these wires being in particular wound on the elongated reinforcing element. This assembly may in particular form at least one layer of the continuous envelope type, for example of circular or oval or square cross section.

When the electrical cable of the invention comprises an elongated reinforcing member, said assembly may be positioned around the elongate reinforcing member.

The metal strands may be of round, trapezoidal or Z-shaped cross section.

When the strands are of round cross section, they can have a diameter ranging from 2.25 mm to 4.75 mm. When the strands are of non-round cross section, their equivalent diameter in round section can also range from 2.25 mm to 4.75 mm.

Of course, it is preferable that all constituent strands of an assembly have the same shape and the same dimensions.

In a preferred embodiment of the invention, the elongate reinforcing member is surrounded by at least one layer of an aluminum alloy wire assembly conforming to the first object or second object of the invention.

Preferably, the metal strands constituting at least one layer of an assembly of aluminum alloy metal strands of the invention are capable of conferring on said layer a substantially regular surface, each constituent strand of the layer being able to have a cross-section of complementary shape to the (s) strand (s) which is / are adjacent (s).

According to the invention, "metal strands capable of conferring on said layer a substantially regular surface, each constituent strand of the layer may in particular have a cross section of shape complementary to the (x) strand (s) which is / are adjacent thereto ( (s) 'means that: the juxtaposition or the nesting of all the constituent strands of the layer forms a continuous envelope (without irregularities), for example of circular or oval or square section.

Thus, the Z-shaped or trapezoid-shaped cross-section strands make it possible to obtain a regular envelope, unlike the round cross-section strands. In particular, strands of Z-shaped cross-section are preferred.

Even more preferably, said layer formed by the assembly of the metal strands has a cross section in the form of a ring.

The elongated reinforcing member may be typically a composite or metallic member. By way of example, mention may be made of steel strands or composite strands of aluminum in an organic matrix.

The electrical transport wire of the invention may be twisted around the elongated reinforcing element, in particular when the electrical cable of the invention comprises an assembly of aluminum alloy electrical transport wires conforming to the first or second object. of the invention (ie metal strands).

1. i) Former un alliage d'aluminium en fusion comprenant de l'aluminium, du zirconium, des impuretés inévitables, et optionnellement un élément choisi parmi le cuivre, le fer et leur mélange ;
2. ii) Couler l'alliage en fusion de l'étape i), pour obtenir un alliage brut de coulée ;
3. iii) Laminer l'alliage brut de coulée de l'étape ii), pour obtenir un alliage laminé,
4. iv) Chauffer l'alliage laminé de l'étape iii) pour obtenir ledit fil de transport électrique en alliage d'aluminium, ledit alliage comprenant au moins 80 parties en poids de zirconium sous forme de précipités (Al₃Zr) pour 100 parties en poids de zirconium dans ledit alliage d'aluminium.

The fourth subject of the present invention is a method of manufacturing an electric transport wire according to the first subject of the invention, said method being characterized in that it comprises the following steps:

1. i) forming a molten aluminum alloy comprising aluminum, zirconium, unavoidable impurities, and optionally an element selected from copper, iron and mixtures thereof;
2. ii) Pouring the molten alloy of step i), to obtain a cast alloy;
3. iii) laminating the crude casting alloy of step ii), to obtain a rolled alloy,
4. iv) heating the rolled alloy of step iii) to obtain said aluminum alloy electrical transport wire, said alloy comprising at least 80 parts by weight of zirconium in the form of precipitates (Al ₃ Zr) per 100 parts by weight; zirconium weight in said aluminum alloy.

The inventors of this application have discovered surprising that the electrical conductivity of the alloy obtained at the end of the heating step iv) is increased. Thus, thanks to the process of the invention, and in particular thanks to the heating step iv), sufficient zirconium precipitates are formed to allow the increase of the electrical conductivity with respect to an alloy of the prior art comprising zirconium. In addition, the addition of iron and / or copper in the alloy, associated with the heating step iv) of the process of the invention, leads to an alloy having both improved mechanical properties, especially in terms of resistance to hot creep and breaking strength, and better electrical conductivity.

Step i) can be conventionally carried out by incorporating a parent alloy (ie " master alloy " in English) comprising aluminum; zirconium; optionally iron and / or copper; in a bath of molten aluminum, substantially pure. It is also possible to perform step i) by adding zirconium, and optionally an element chosen from copper, iron and their mixture, to molten aluminum, and then mixing.

Stage ii) makes it possible in particular to form, by cooling the casting (ie solidification), a cast aluminum alloy, in particular in the form of bar or bar, preferably cylindrical. The cross section of the bar can range for example from 500 mm ² to 2500 mm ² or more.

In a particular embodiment, the casting temperature in step ii) is from about 680 ° C to about 850 ° C, and preferably from about 710 ° C to about 770 ° C.

In a particular embodiment, the cooling during the casting step ii) is carried out at a speed of at least 50 ° C / min, from the casting temperature up to about 500 ° C.

For example, the casting step can be carried out continuously, in particular using a rotating wheel, called "casting".

Step iii) rolls said cast aluminum alloy into a rolled alloy.

The steps of casting ii) and rolling iii) make it possible to control the microstructure of the zirconium precipitates in said alloy while avoiding the formation of large zirconium precipitates, and thus guarantee the production of an aluminum alloy having good mechanical properties, especially in terms of breaking strength.

Said laminated alloy preferably has a cross section, round. The diameter of the cross section may be, for example, from about 7 mm to about 26 mm.

In a particular embodiment, the step iii) of rolling can be carried out hot, especially at a temperature ranging from 400 to 550 ° C.

Stage iv) of heating the rolled alloy makes it possible, in turn, to control the microstructure of the zirconium precipitates in said alloy and also to form sufficient zirconium precipitates. Thus, at the end of step iv), said aluminum alloy manufactured according to the process of the invention comprises at least 80 parts by weight of zirconium in the form of precipitates per 100 parts by weight of zirconium in said alloy. 'aluminum.

In a particular embodiment, this step iv) makes it possible to obtain at least 90 parts by weight of zirconium in the form of precipitates per 100 parts by weight of zirconium in the aluminum alloy manufactured according to the method of the invention.

This step iv) may preferably be a so-called "income" step, well known to those skilled in the art; said income stage being in particular different from a so-called "annealing" step also known under the anglicism " annealing step " . The annealing step makes it possible to increase the mechanical elongation of an alloy by heating it, and thus to be able to easily deform it once annealed, while the income step makes it possible, in turn, to increase the resistance. mechanical alloy.

In a particular embodiment, step iv) is carried out at a temperature ranging from 300 to 500 ° C, preferably from 350 to 450 ° C, and even more preferably from 400 to 450 ° C.

In a preferred embodiment, the duration of the heating step iv) ranges from 100 to 500 hours, preferably from 100 to 350 hours, and even more preferably from 100 to 300 hours.

It is important to note that the temperature and times used in said step iv) are interdependent. By way of example of the time / temperature pairs used during step iv), the following time / temperature combinations can notably be mentioned: 100 hours / 450 ° C., 200 hours / 400 ° C., and 340 hours / 350 ° C. vs.

The control of the heating time during step iv) for a given temperature can be carried out by transmission electron microscopy.

The heating according to step iv) can be carried out using an electric furnace (i.e. resistance furnace) and / or an induction furnace and / or a gas oven.

In order to improve the formation of zirconium precipitates (Al ₃ Zr), the heating of step iv) can be carried out by carrying out a slow rise in temperature, in particular by about 5 ° C. per minute.

According to a particular embodiment, the method of manufacturing the electric transport wire according to the first subject of the invention further comprises the following step:
v) cold-working said electric transport wire of step iv), to obtain an electric transport wire with the desired dimensions.

The cold working step v) may be a drawing step in order to obtain said electric transport wire with the desired dimensions (e.g. final diameter). It can be performed at a temperature of at most 80 ° C.

According to a preferred embodiment, step v) makes it possible to obtain metal alloy strands (or electrical transport wires) of aluminum alloy, in particular of round or trapezoidal or Z-shaped cross section. The diameter of the cross section can range from 0.2mm to 5.0mm.

According to a preferred embodiment, the method according to the fourth subject of the invention further comprises the following step:
vi) forming by chemical conversion a porous layer of alumina hydroxide on the surface of said electric transport wire.

Step vi) may be performed with the electrical transport wire from step iv) or from step v) if it exists.

In a preferred embodiment, the porous layer of alumina hydroxide surrounding said electrical transport wire and formed in step vi), is preferably a layer that is in direct physical contact with said electrical transport wire. in aluminum alloy. In other words, the electrical cable thus formed does not preferably comprise a layer interposed between the porous layer of alumina hydroxide and said aluminum alloy electrical transport wire.

The pores of said porous alumina hydroxide layer are optionally arranged substantially evenly (or homogeneously) all along the outer surface of the porous alumina hydroxide layer, and they may all have substantially the same dimensions .

1. A) Former un alliage d'aluminium en fusion comprenant de l'aluminium, du zirconium, des impuretés inévitables, et optionnellement un élément choisi parmi le cuivre, le fer et leur mélange,
2. B) Couler l'alliage en fusion obtenu à l'étape A), pour obtenir un alliage brut de coulée, notamment sous forme d'une barre,
3. C) Laminer l'alliage brut de coulée de l'étape B), pour obtenir un alliage laminé
4. D) Chauffer l'alliage laminé de l'étape C),
5. E) Eventuellement tréfiler l'alliage obtenu à l'étape D) pour obtenir ledit fil de transport électrique avec le diamètre final souhaité, et
6. F) Former ladite couche poreuse d'hydroxyde d'alumine par conversion chimique.

The subject of the present invention is a method of manufacturing an electric transport wire according to the second subject of the invention, said method being characterized in that it comprises the following steps:

1. A) forming a molten aluminum alloy comprising aluminum, zirconium, unavoidable impurities, and optionally an element chosen from copper, iron and their mixture,
2. B) Pouring the molten alloy obtained in step A), to obtain a cast alloy, in particular in the form of a bar,
3. C) Laminating the Casting Alloy of Step B), to obtain a rolled alloy
4. D) heating the rolled alloy of step C),
5. E) optionally drawing the alloy obtained in step D) to obtain said electric transport wire with the desired final diameter, and
6. F) forming said porous layer of alumina hydroxide by chemical conversion.

Step A) may be conventionally carried out by incorporating a master alloy (ie " master alloy " in English) comprising aluminum; zirconium; optionally iron and / or copper; in a bath of molten aluminum, substantially pure. It is also possible to carry out step A) by adding zirconium, and optionally an element chosen from copper, iron and their mixture, to molten aluminum, and then mixing.

Stage B) makes it possible in particular to form, by cooling the crude casting (ie solidification), a cast aluminum alloy, especially in the form of bar or bar, preferably cylindrical. The cross section of the bar can range for example from 500 mm ² to 2500 mm ² or more.

In a particular embodiment, the casting temperature in step B) ranges from about 680 ° C to about 850 ° C, and preferably from about 710 ° C to about 770 ° C.

In a particular embodiment, the cooling in the casting step B) is carried out at a speed of at least 50 ° C / min, from the casting temperature up to about 500 ° C.

For example, the casting step can be carried out continuously, in particular using a rotating wheel, called "casting".

Step C) rolls said cast aluminum alloy into a rolled alloy.

The casting steps B) and the rolling step C) make it possible to control the microstructure of the zirconium precipitates in said alloy by avoiding the formation of large zirconium precipitates, and thus guarantee the obtaining of an aluminum alloy having good properties. mechanical, especially in terms of breaking strength.

Said laminated alloy preferably has a cross section, round. The diameter of the cross section may be, for example, from about 7 mm to about 26 mm.

In a particular embodiment, the rolling step C) can be carried out hot, in particular at a temperature ranging from 400 to 550 ° C.

In a particular embodiment, step D) is carried out at a temperature ranging from 300 to 500 ° C, preferably from 350 to 450 ° C, and even more preferably from 400 to 450 ° C.

In a preferred embodiment, the duration of the heating step D) ranges from 100 to 500 hours, preferably from 100 to 350 hours, and even more preferably from 100 to 300 hours.

In an even more preferred embodiment, step D) is carried out at a temperature between 400 and 450 ° C, for 100 to 500 hours.

It is important to note that the temperature and time parameters used in said step D) are interdependent. As an example of the time / temperature pairs used during step D), the following time / temperature combinations can notably be mentioned: 100 hours / 450 ° C. and 200 hours / 400 ° C.

The control of the heating time in step D) for a given temperature can be carried out by transmission electron microscopy.

Stage D) for heating the rolled alloy (i.e. heat treatment step) makes it possible to control the microstructure of the zirconium precipitates in said alloy and also to form sufficient zirconium precipitates. Thus, at the end of step D), said aluminum alloy manufactured according to the process according to the fifth subject of the invention may comprise at least 80 parts by weight of zirconium in the form of precipitates per 100 parts by weight of zirconium in said aluminum alloy.

In order to improve the formation of the zirconium precipitates (Al ₃ Zr), the heating of stage D) can be carried out by carrying out a slow rise in temperature, in particular by approximately 5 ° C. per minute.

Advantageously, this step D) makes it possible to obtain at least 90 parts by weight of zirconium in the form of precipitates per 100 parts by weight of zirconium in the aluminum alloy manufactured according to the process according to the fifth subject of the invention.

This step D) may preferably be a so-called "income" step, well known to those skilled in the art; said income stage being in particular different from a so-called "annealing" step also known under the anglicism " annealing step " . The annealing step makes it possible to increase the mechanical elongation of an alloy by heating it, and thus to be able to easily deform it once annealed, while the income step makes it possible, in turn, to increase the resistance. mechanical alloy.

The heating according to step D) can be carried out using an electric furnace (ie resistance furnace) and / or an induction furnace and / or a gas oven.

The drawing step E) makes it possible to obtain said electric transport wire with the desired dimensions (e.g. final diameter). It can be performed at a temperature of at most 80 ° C.

According to a preferred embodiment, step E) makes it possible to obtain metal alloy strands (or electrical transport wires) of aluminum alloy, in particular of round or trapezoidal or Z-shaped cross section. The diameter of the cross section can range from 0.2mm to 5.0mm.

In a preferred embodiment, the porous layer of alumina hydroxide surrounding said electrical transport wire and formed in step F) is preferably a layer that is in direct physical contact with said electrical transport wire. in aluminum alloy. In other words, the electrical cable thus formed does not preferably comprise a layer interposed between the porous layer of alumina hydroxide and the aluminum alloy electrical transport wire.

The pores of said porous alumina hydroxide layer are optionally arranged substantially evenly (or homogeneously) all along the outer surface of the porous alumina hydroxide layer, and they may all have substantially the same dimensions .

In a particularly advantageous embodiment, step vi) of the method according to the fourth subject of the invention or step F) of the process according to the fifth subject of the invention is carried out by anodization.

Anodizing is a surface treatment that can be formed by anodic oxidation, from the electrical transport wire from step iv) (or step D)) or step v) (or from step E)) if it exists, the porous layer of alumina hydroxide. Thus, the anodizing will consume a portion of the electrical transport wire to form said porous layer of alumina hydroxide.

During anodization, the porous layer of alumina hydroxide is formed from the surface of said electric transport wire to the core of said electric transport wire, in contrast to an electrolytic deposition.

Anodizing is conventionally based on the principle of electrolysis of water. It consists of immersing the electric transport wire in a bath anodizing, said electric transport wire being placed at the positive pole of a DC generator.

The anodizing bath is more particularly an acid bath, preferably a phosphoric acid bath or a sulfuric acid bath. These are respectively phosphoric anodizing or sulfuric anodizing.

When the porous layer of alumina hydroxide is advantageously formed by anodization, the electrolytic parameters are imposed by a current density and a conductivity of the bath. For a desired thickness on a prototype electric transport wire of 8 to 10 μm, the current density is preferably set at 55 to 65 A / dm ² , the voltage is set at 20 to 21 V, and the intensity is fixed at 280 to 350 A.

This current density makes it possible to ensure that a sufficient quantity of pores has been formed.

1. a) dégraisser ledit fil de transport électrique, et/ou
2. b) décaper ledit fil de transport électrique.

The method according to the fourth object or fifth object of the invention may further comprise at least one of the following steps, prior to the chemical conversion step vi) or F):

1. a) degreasing said electric transport wire, and / or
2. b) etching said electric transport wire.

Preferably, step a) and step b) can be carried out concomitantly.

Furthermore, the method according to the fourth object or fifth object of the invention may further comprise the following step, prior to the chemical conversion step vi) or F):
c) Neutralizing said electric transport wire.

In a particularly preferred embodiment, the method according to the fourth object or fifth object of the invention may comprise said three steps a), b) and c), step c) being performed after steps a) and b ).

The purpose of the degreasing step a) is to eliminate the various bodies and particles contained in the greases that may be present on the surface of the electric transport wire.

It can be performed chemically or electrolytically.

By way of example, the degreasing step a) can be carried out by at least partially immersing the electric transport wire in a solution comprising at least one surfactant as a degreasing agent.

The stripping step b) serves to remove oxides that may be present on the surface of the electric transport wire. There are several methods of stripping: chemical, electrolytic or mechanical.

Preferably, a chemical etching may be used consisting of removing the oxides by dissolution, or even bursting of the oxide layer, without attacking the material of the underlying electrical transport wire.

By way of example, the stripping step b) can be carried out by at least partially immersing the electric transport wire in a solution comprising a base as a stripping agent.

When step a) and step b) are carried out concomitantly, a single solution comprising a degreasing agent and a etchant may be used to both etch and degrease the electrical transport wire.

The neutralization step c) makes it possible to condition the electric transport wire before the chemical conversion step vi) or F).

More particularly, when the chemical conversion step vi) or F) is an anodizing step, the step c) of neutralization consists in conditioning the electric transport wire by plunging it at least partially into a solution identical to the bath of anodizing provided in the chemical conversion step vi) or F), in order to put the surface of the electric transport wire at the same pH as the anodizing bath of the anodizing step vi) or F).

This solution also makes it possible, on the one hand, to eliminate certain traces of oxides that can hinder anodization, and on the other hand to eliminate any residues of the etchant. Neutralization makes it possible to put the surface of the aluminum at the same pH as the anode bath.

By way of example, the neutralization step c) can be carried out by at least partially immersing the electric transport wire in a solution comprising an acid as neutralizing agent.

For example, it is preferable first of all to strip and degrease said aluminum electrical transport wire, by immersing it in a soda solution and surfactants such as for example the GARDOCLEAN referenced solution marketed by the Company CHEMETALL (30-50 g / L of sodium hydroxide), especially at a temperature ranging from 40 to 60 ° C, for a period of about 30 seconds. Then, said electric transport wire can be immersed in a solution of sulfuric acid (20% by weight of sulfuric acid in distilled water) to perform the step c) of neutralization, preferably at room temperature (ie 25 ° C), for 10 seconds.

Prior to the anodizing step vi) or F), said electric transport wire can then be smoothed to have a glossy appearance and then rinsed. Brightening eliminates a surface roughness that impacts the gloss associated with the reflection of light. The brightening can be carried out in a solution of acid assisted or not current. In the first case, it is an electrochemical brilliance. For example, the samples tested in the laboratory were made from the LUMIA range of the company COVENTYA.

The anodizing step vi) or F) can then be performed.

By way of example, the electrical transmission wire made of aluminum alloy, for example with a diameter of 3 mm, will be anodized by forming a porous layer of alumina hydroxide all around said electric transport wire, by sulfuric anodizing ( 20 to 30% by weight of sulfuric acid in distilled water) at a temperature of 30 ° C, or by phosphoric anodization (8 to 30% by weight of phosphoric acid in distilled water) at room temperature (ie 25 ° C), under the application of a current density between 55 and 65 A / dm ² . Said aluminum alloy electrical transport wire obtained is thus covered with a porous layer of alumina hydroxide.

In a particular embodiment, the method according to the fourth object or fifth object of the invention further comprises after the chemical conversion step vi) or F), and in particular anodizing, the following step:
vii) sealing the pores of said porous layer of alumina hydroxide.

This step vii) makes it possible to improve the compactness of the alumina hydroxide layer. Following this step vii), all the pores on the surface of the alumina hydroxide layer are capped.

Step vii) may for example be performed by performing hot hydration of said electrical transport wire, by dipping said electrical transport wire into boiling water or hot water.

The clogging may be carried out in water optionally with an additive, for example nickel salt at a temperature above 80 ° C, preferably between 90 and 95 ° C.

Advantageously, said electric transport wire obtained after the chemical conversion step vi) or F) or said electric transport wire obtained after the sealing step vii), is rinsed with osmosis water.

• Y) fabriquer un fil de transport de transport électrique selon le procédé de fabrication conforme au quatrième ou cinquième objet de l'invention, et
• Z) Positionner ledit fil de transport électrique autour de l'élément allongé de renforcement.

The subject of the present invention is a method of manufacturing an electric cable according to the third subject of the invention, said method comprising the following steps:

• Y) manufacturing an electric transport transport wire according to the manufacturing method according to the fourth or fifth subject of the invention, and
• Z) Position said electric transport wire around the elongate reinforcing member.

Thus, the method of manufacturing the electric cable of the invention is an easy process to implement. In addition, it provides an electrical cable having both good electrical properties (in terms of electrical capacitance and conductivity) and good mechanical properties (in terms of breaking strength and resistance to hot creep). .

More particularly, when said cable comprises an aluminum electrical transport wire assembly, step Y) makes it possible to obtain said electrical transport wires optionally covered with a layer of alumina hydroxide, and step Z) is to position the electrical transport son around the reinforcing element, so as to form at least one layer of said electrical transport son around said reinforcing element. Preferably, the electric transport wires are twisted around said reinforcing element.

In a particular embodiment, in the layer formed around said reinforcing element, each electric transport wire has a cross section of complementary shape to the (s) strand (s) adjacent thereto, and being capable of conferring on said layer a substantially regular surface.

The electric cable according to the invention may have an apparent diameter (that is to say outside diameter) ranging from 10 to 100 mm.

The electric cable of the invention may be more particularly a high voltage electrical transmission cable, in particular of high voltage overhead line type of at least 225 kV and up to 800 kV (i.e. OHL cables). This type of cable is usually stretched between two pylons.

Other features and advantages of the present invention will appear in light of the examples which follow with reference to the annotated figures, said examples and figures being given for illustrative and not limiting.

The figure 1 schematically represents a structure, in cross section, of a first variant of an electric cable according to the invention.

The figure 2 schematically represents a structure, in cross section, of a second variant of an electric cable according to the invention.

The figure 3 schematically represents a structure, in cross section, of a third variant of an electric cable according to the invention.

The figure 4 represents a transmission electron microscopy (TEM) view of the aluminum alloy electrical transport wire of the electrical cable of the invention.

The figure 5 represents the curves of the electrical conductivity of the electric transport wire of the electric cable of the invention as a function of the heating time of step iv) of the fourth subject of the invention for different heating temperatures.

For the sake of clarity, the same elements have been designated by identical references. Similarly, only the essential elements for understanding the invention have been shown schematically, and this without respect of the scale.

The figure 1 represents a first variant of a high voltage electric transmission electric cable of the OHL 100A type according to the invention, seen in cross section, comprising three layers of a 10A assembly of aluminum alloy wire strands 1A of the invention. These three layers surround an elongate central reinforcing element 20A. The metal strands 1A constituting said layers have a cross section of round shape.

The figure 2 represents a second variant of a high-voltage electric transmission electric cable of the OHL 100B type according to the invention, seen in cross-section, comprising two layers of an assembly 10B of metal strands 1B of aluminum alloy of the invention. These two layers surround an elongated central reinforcing element 20B. The metal strands 1B constituting said layers have a trapezoidal cross section.

The figure 3 represents a third variant of a high-voltage electric transmission electric cable of the OHL 100C type according to the invention, seen in cross-section, comprising two layers of a 10C assembly of metal strands 1C of aluminum alloy of the invention. These two layers surround an elongated central reinforcing element 20C. The constituent metal strands 1C of said layers have a Z-shaped cross section (or of "S" shape according to the orientation of the Z). The geometry of the strands in the shape of "Z" makes it possible to obtain a surface practically provided with no gaps that can generate accumulations of moisture and thus poles of corrosion.

The central element 20A, 20B, 20C, which is an elongated reinforcement, represented in the Figures 1, 2 and 3 may be for example steel strands 2A, 2B, 2C or composite strands 2A, 2B, 2C of aluminum in an organic matrix.

In alternative embodiments shown on the Figures 1 to 3 , it is possible to modify the number of strands 1A, 1B, 1C of each layer, their shape, the number of layers or the number of steel strands or composite strands 2A, 2B, 2C, as well as the nature of the aluminum.

Preparation of an aluminum alloy electrical transport wire according to the process according to the fourth subject of the invention

• Etape i) : après avoir incorporé un alliage maître d'aluminium, de zirconium, de cuivre et de fer, dans un bain fondu d'aluminium pur à plus de 99,5% en poids, on a mélangé le tout pour homogénéiser l'aluminium pur et l'alliage maître, et ainsi former un alliage en fusion.
• Etape ii) : on a ensuite coulé l'alliage en fusion dans une filière cylindrique pour former un barreau d'un alliage dit « brut de coulée », que l'on a solidifié par refroidissement : le barreau cylindrique formé avait un diamètre de 30 mm.
• Etape iii) : on a laminé à une température de 25°C le barreau cylindrique, directement formé à l'étape précédente, pour obtenir un barreau de plus petit diamètre, à savoir un barreau d'un diamètre de 10 mm.
• Etape iv) : on a chauffé dans un four à résistance conventionnel le barreau de l'étape précédente à 400°C pendant 150 heures pour former un fil de transport électrique en alliage d'aluminium comprenant de l'aluminium, 0,3% de zirconium, 0,15% de fer et 0,001% de cuivre, ledit alliage comprenant 80 parties en poids de zirconium sous forme de précipités pour 100 parties en poids de zirconium dans ledit alliage. La quantité de zirconium sous forme de précipités dans le fil de transport électrique en alliage d'aluminium a été déterminée à l'aide du diagramme de phase, par calcul de la quantité de zirconium restant dans la solution solide (i.e. zirconium n'étant pas sous forme de précipités) à l'issue de l'étape iv).
• Etape v) : on a tréfilé enfin à froid le fil de transport électrique de l'étape précédente pour obtenir un fil d'alliage de l'invention (i.e. brin métallique d'alliage) de 3,5 mm de diamètre.

An alloy was prepared according to the method of the invention as follows:

• Step i): after having incorporated a master alloy of aluminum, zirconium, copper and iron, in a molten bath of pure aluminum to more than 99.5% by weight, the whole was mixed to homogenize the pure aluminum and the master alloy, and thus form a molten alloy.
• Step ii): the molten alloy was then cast in a cylindrical die to form a bar of a so-called "raw cast" alloy, which was solidified by cooling: the cylindrical bar formed had a diameter of 30 mm. mm.
• Step iii): The cylindrical bar, directly formed in the previous step, was rolled at a temperature of 25 ° C. to obtain a bar of smaller diameter, namely a bar with a diameter of 10 mm.
• Step iv): the bar of the preceding step was heated in a conventional resistance furnace at 400 ° C for 150 hours to form an aluminum alloy electrical transport wire comprising aluminum, 0.3% of zirconium, 0.15% iron and 0.001% copper, said alloy comprising 80 parts by weight of zirconium in the form of precipitates per 100 parts by weight of zirconium in said alloy. The amount of zirconium in the form of precipitates in the aluminum alloy electrical transport wire was determined using the phase diagram, by calculating the amount of zirconium remaining in the solid solution (ie zirconium not being as precipitates) at the end of step iv).
• Step v): Finally, the electrical transport wire of the preceding step was cold-drawn to obtain an alloy wire of the invention (ie alloy metal strand) of 3.5 mm in diameter.

The aluminum alloy of the electric transport wire included at most 0.8% by weight of unavoidable impurities.

The figure 4 shows a transmission electron microscopic view (TEM) of the aluminum alloy as prepared above bright field mode (English "BF: Bright Field") ( figure 4a ) and in dark field mode (in English " DF: Dark Field ") ( figure 4b ).

Transmission electron microscopy (TEM) was carried out with a high-resolution transmission electron microscope marketed under the reference ARM 200S by GEOL.

The diameter of the zirconium precipitates in the alloy was determined by TEM. To do this, an alloy sample as prepared above was taken, polished to obtain an alloy thickness of about 100 microns, and electrochemically pierced to obtain a transparent sample thickness to electrons ranging from 50 to about 100 nm.

It has thus been found that the process according to the invention, and in particular the casting steps ii) and heating stages iv), makes it possible to obtain a homogeneous dispersion of controlled microstructure of zirconium precipitates and in particular, the obtaining spherical zirconium precipitates with a diameter ranging from about 1 to 100 nm.

On the other hand , it has been found that when the operating conditions of the casting step ii) and / or the heating step iv) are not optimal (eg casting step performed at a temperature that is too low, that is to say at a temperature below 680 ° C, cooling rate during the casting step too low, that is to say less than 50 ° C / min, heating step performed for a period of time too long, that is to say greater than 500 hours), the zirconium precipitates obtained at the end of step iv) were coarse, in particular with a diameter greater than 100 nm.

Resistance to breaking of the aluminum alloy electrical transport wire prepared according to the method according to the fourth subject of the invention

Table 1 below shows the tensile strength (in MPa) of several aluminum alloy electrical transport wires A1, A2, A3, A4 and A01, their electrical conductivity (in% IACS) and the loss of their properties mechanical after aging at 230 ° C for 1 hour (ie loss of breaking strength, in ΔUTS).

A1, A2, A3 and A4 were manufactured according to the process of the invention as described in the example above with different heating parameters according to the amount of zirconium they contained, and A01 was marketed under the reference AI1120 by Nexans. A01 is not part of the invention since it does not contain zirconium. <b> TABLE 1 </ b> Alloy Zirconium content (%) Copper content (%) Iron content (%) Resistance to rupture before aging (MPa) Electrical conductivity (% IACS) ΔUTS (%) A01 0 0.17 0.27 229.8 59.1 -18.2 A1 0.568 0.17 0.27 220.4 59.4 -9.3 A2 0.487 0.17 0.27 225.3 59.3 -6.7 A3 0.426 0.17 0.27 207.1 59.1 -7.0 A4 0.349 0.17 0.27 221.8 59.5 -8.6

A1, A2, A3 and A4 were respectively obtained with the following heating parameters of step iv): 400 ° C / 300 hours, 400 ° C / 250 hours, 400 ° C / 220 hours and 400 ° C / 180 hours.

Thus, according to Table 1 illustrated above, it can be seen that the aluminum alloy electrical transport wires manufactured according to the process according to the invention have good mechanical properties before and after aging and good electrical properties. .

In addition, the presence of zirconium in the aluminum alloy reduces the loss of mechanical properties after aging, while ensuring good electrical properties.

Study of the electrical conductivity of the aluminum alloy electrical transport wire as a function of time and the heating temperature of the fourth subject of the invention

The figure 5 shows the electrical conductivity of the aluminum alloy electrical transport wire of the invention as a function of the heating time of step iv) of the process according to the invention when step iv) is carried out at a heating temperature 450 ° C (curve A), 400 ° C (curve B) and 350 ° C (curve C).

The alloy used in this example was prepared as in the examples described above and included 0.35% zirconium, 0.27% iron and 0.17% copper.

It can thus be seen that the temperature and time parameters used during said step iv) are interdependent and have a direct impact on the electrical conductivity of the alloy obtained. By way of example of time / temperature pairs allowing in step iv) to form sufficient zirconium precipitates and thus to obtain a conductivity of at least 57% IACS, the following time / temperature pairs are found: About 100 hours / 450 ° C, about 200 hours / 400 ° C, and about 340 hours / 350 ° C.

Preparation of an aluminum alloy electrical transport wire according to the method according to the fifth subject of the invention

• Etape A) : après avoir incorporé un alliage maître d'aluminium et de zirconium, dans un bain fondu d'aluminium pur à plus de 99,5% en poids, on a mélangé le tout pour homogénéiser l'aluminium pur et l'alliage maître, et ainsi former un alliage en fusion.
• Etape B) : on a ensuite coulé l'alliage en fusion dans une filière cylindrique pour former un barreau d'un alliage dit « brut de coulée », que l'on a solidifié par refroidissement : le barreau cylindrique formé avait un diamètre de 30 mm.
• Etape C) : on a laminé à une température de 25°C le barreau cylindrique, directement formé à l'étape précédente, pour obtenir un barreau de plus petit diamètre, à savoir un barreau d'un diamètre de 10 mm.
• Etape D) : on a chauffé le barreau de l'étape précédente à 400°C pendant 180 heures pour former un fil de transport électrique en alliage d'aluminium comprenant de l'aluminium et 0,35% de zirconium.
• Etape E) : on a tréfilé à froid ledit fil de transport électrique de l'étape précédente pour obtenir un fil d'alliage de l'invention (i.e. brin métallique d'alliage) de 3,5 mm de diamètre.
• Etapes a) et b) : on a décapé et dégraissé ledit fil de transport électrique en aluminium de l'étape précédente, en le plongeant dans une solution de soude et de tensio-actifs commercialisée sous la référence GARDOCLEAN par la société CHEMETALL (30-50 g/L de soude), à une température allant de 40 à 60°C environ, pendant une durée de 30 secondes environ.
• Etape c) : Puis, on a plongé ledit fil de transport électrique en aluminium de l'étape précédente dans une solution d'acide sulfurique (20% en poids d'acide sulfurique dans de l'eau distillée), à température ambiante (i.e. 25°C), pendant 10 secondes.
• Etape F) : on a formé par anodisation sulfurique (20% en poids d'acide sulfurique dans de l'eau distillée) à une température de 25 à 35°C, une couche poreuse d'hydroxyde d'alumine en surface du fil de transport électrique de l'étape précédente, sous l'application d'une densité de courant comprise entre 55 et 65 A/dm². Ledit fil de transport électrique en alliage d'aluminium obtenu est ainsi recouvert d'une couche poreuse d'hydroxyde d'alumine. L'épaisseur de ladite couche poreuse d'hydroxyde d'alumine allait de 8 à 10 µm environ.
• Etape vii) : on a colmaté les pores de la couche poreuse d'hydroxyde d'alumine telle que formée à l'étape précédente en plongeant ledit fil de transport électrique de l'étape précédente dans de l'eau chaude.

An electrically conductive element made of aluminum alloy A6 was prepared according to the process according to the invention as follows:

• Step A): after having incorporated a master alloy of aluminum and zirconium, in a melt of pure aluminum to more than 99.5% by weight, the whole was mixed to homogenize the pure aluminum and the alloy master, and thus form a molten alloy.
• Step B): The molten alloy was then cast in a cylindrical die to form a bar of a so-called "raw cast" alloy, which was solidified by cooling: the cylindrical bar formed had a diameter of 30 mm. mm.
• Step C): The cylindrical bar, directly formed in the previous step, was rolled at a temperature of 25 ° C. to obtain a bar of smaller diameter, namely a bar with a diameter of 10 mm.
• Step D): The bar of the previous step was heated at 400 ° C for 180 hours to form an aluminum alloy electrical transport wire comprising aluminum and 0.35% zirconium.
• Step E): said electric transport wire of the preceding step was cold-drawn to obtain an alloy wire of the invention (ie metallic strand alloy) 3.5 mm in diameter.
• Steps a) and b): the aluminum electrical transport wire was stripped and degreased from the previous step, by immersing it in a solution of sodium hydroxide and surfactants marketed under the reference GARDOCLEAN by the company CHEMETALL (30- 50 g / l of sodium hydroxide), at a temperature ranging from 40 to 60 ° C, for a period of about 30 seconds.
• Step c): Then, said aluminum electrical transport wire of the preceding step was immersed in a solution of sulfuric acid (20% by weight of sulfuric acid in distilled water) at room temperature (ie 25 ° C), for 10 seconds.
• Step F): sulfuric anodization (20% by weight of sulfuric acid in distilled water) was formed at a temperature of 25 to 35 ° C, a porous layer of alumina hydroxide on the surface of the electrical transport of the previous step, under the application of a current density between 55 and 65 A / dm ² . Said aluminum alloy electrical transport wire obtained is thus covered with a porous layer of alumina hydroxide. The thickness of said porous alumina hydroxide layer was about 8 to 10 μm.
• Step vii): The pores of the porous alumina hydroxide layer as formed in the preceding step were sealed by immersing said electric transport wire from the previous step in hot water.

The aluminum alloy A5 of the electric transport wire included at most 0.8% by weight of unavoidable impurities.

The diameter of the zirconium precipitates was determined by the MET method as described in Example 1, on the alloy A5 as prepared at the end of the drawing step E) (ie before the stripping steps, degreasing, neutralization, anodizing and clogging).

The inventors of the present application have thus been able to observe that the process according to the invention makes it possible to obtain a homogeneous dispersion of controlled microstructure of zirconium precipitates and in particular to obtain spherical zirconium precipitates with a diameter of from 1 to about 20 nm.

Table 2 below shows the temperature resistance (in ° C) of several aluminum alloy electrical transport wires A5, A6, A02 and A03, their electrical conductivity (in% IACS), their emissivity, their absorption, their diameter, the diameter and the cross-section of the corresponding cables (in mm), the intensity (in A) and the intensity gain (in%) of the cables respectively comprising the aluminum alloy electrical transport wires A03, A5 and A6 with respect to the cable comprising the aluminum alloy electrical transport wire A02.

A6 was manufactured according to the method according to the fourth subject of the invention and as described in the first example of the present application (with the heating parameters of step iv) following: 400 ° C / 180 hours).

It included aluminum and 0.35% zirconium (said alloy did not include iron and no copper). A6 did not include a porous layer of alumina hydroxide.

A02 (pure aluminum) was marketed under the reference Al1350 by Nexans. A02 did not include a porous layer of alumina hydroxide.

A03 was made from A02, performing only steps a), b), c), F) and vii) described above in this example. A03 thus included a porous layer of alumina hydroxide.

A02 and A03 do not form part of the invention since they do not include zirconium. <b> TABLE 2 </ b> A02 A03 A6 AT 5 Maximum temperature (° C) 80 ° C 80 ° C 210 ° C 210 ° C Conductivity (% IACS) 62% 62% 60% 60% Em issivity 0.4 0.92 0.4 0.92 Absorption 0.85 0.5 0.85 0.5 Diameter of the wire (mm) 3,500 3,500 3,513 3,513 Cable diameter (mm) 31.50 31.50 32.52 31.52 Section (mm ² ) 346.46 346.46 357.67 357.67 Intensity (A) 1360 1549 2334 2688 Intensity gain (%) - 13.91 71.59 97.68

In addition to improved mechanical properties at a temperature of 210 ° C in continuous use for a period of up to 40 years, the maximum allowable intensity is particularly increased thanks to the invention, as shown by the calculations in Table 2 above. , made on round electric transport wires.

Claims (16)

Electrical aluminum alloy transport wire comprising aluminum, zirconium precipitates (Al ₃ Zr) and unavoidable impurities, characterized in that said electrical transport wire comprises at the surface a porous layer of alumina hydroxide . Electrical transport wire according to claim 1, characterized in that said alloy comprises at least 80 parts by weight of zirconium in the form of precipitates (Al ₃ Zr) per 100 parts by weight of zirconium in said aluminum alloy. Electrical transport wire according to claim 1 or 2, characterized in that the electric transport wire comprises a controlled microstructure dispersion of zirconium precipitates (Al ₃ Zr). Electrical transport wire according to any one of the preceding claims, characterized in that said aluminum alloy comprises from 0.05 to 0.6% by weight of zirconium. Electrical transport wire according to any one of the preceding claims, characterized in that the diameter of the zirconium precipitates (Al ₃ Zr) ranges from 1 to 200 nm. Electric transport wire according to any one of the preceding claims, characterized in that said aluminum alloy further comprises a member selected from copper, iron and their mixture. An electrical cable comprising at least one electrical transport wire according to any one of the preceding claims, characterized in that the electrical cable further comprises an elongated reinforcing element. Electrical cable according to claim 7, characterized in that the elongate reinforcing element is surrounded by said aluminum alloy electrical transport wire. Electrical cable according to claim 7 or 8, characterized in that the aluminum alloy electrical transport wire is twisted around the elongated reinforcing element. Electrical cable according to any one of claims 7 to 9, characterized in that it is a power transmission cable (OHL cable). A method of manufacturing an electrical transport wire according to any one of claims 1 to 6, said method being characterized in that it comprises the following steps: A) forming a molten aluminum alloy comprising aluminum, zirconium, unavoidable impurities, and optionally an element chosen from copper, iron and their mixture, B) Pouring the molten alloy obtained in step A), to obtain a cast alloy, in particular in the form of a bar, C) Laminating the Casting Alloy of Step B), to obtain a rolled alloy D) heating the rolled alloy of step C), E) optionally drawing the alloy obtained in step D) to obtain said electric transport wire with the desired final diameter, and F) forming said porous layer of alumina hydroxide by chemical conversion. Process according to claim 11, characterized in that step D) is carried out at a temperature ranging from 300 to 500 ° C for a period ranging from 100 to 500 hours. Process according to claim 11 or 12, characterized in that step F) is carried out by anodization. Process according to any one of claims 11 to 13, characterized in that it further comprises, before step F), at least one of the following steps: a) Degrease the electric transport wire, and / or b) Strip the electrical wire. Process according to any one of claims 11 to 14, characterized in that it further comprises, before step F), the following step:
c) Neutralize the electric transport wire. Process according to any one of claims 11 to 15, characterized in that it further comprises after step F), the following step:
vii) sealing the pores of said porous layer of alumina hydroxide.

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