JP5939530B2 - Aluminum alloy conductor - Google Patents

Description

The present invention relates to an aluminum alloy conductors used as a conductor of the electrical wiring member.

2. Description of the Related Art Conventionally, a member in which a terminal (connector) made of copper or copper alloy (for example, brass) is attached to an electric wire including a copper or copper alloy conductor called a wire harness as an electric wiring body of a moving body such as an automobile, a train, and an aircraft However, in light of the recent weight savings of moving bodies, studies are underway to use aluminum or aluminum alloys that are lighter than copper or copper alloys as conductors of electrical wiring bodies.
The specific gravity of aluminum is about 1/3 of copper, and the electrical conductivity of aluminum is about 2/3 of copper (pure aluminum is about 66% IACS when pure copper is used as the standard of 100% IACS). In order to pass the same current as that of a pure copper conductor wire, the cross-sectional area of the pure aluminum conductor wire needs to be about 1.5 times that of the pure copper conductor wire, but the mass is still about half that of copper. Therefore, there is an advantage.
In addition, said% IACS expresses the electrical conductivity when the resistivity 1.7241 × 10 ⁻⁸ Ωm of universal standard annealed copper (International Annealed Copper Standard) is 100% IACS.

There are some problems in using the aluminum as a conductor of the electric wiring body of the moving body. One of them is improvement of bending fatigue resistance. This is because a wire harness attached to a door or the like is repeatedly subjected to bending stress by opening and closing the door. When a metal material such as aluminum is repeatedly applied and removed as when the door is opened and closed, it breaks at a certain number of repetitions (fatigue failure) even at a low load that does not break at a single load. When the aluminum conductor is used for an opening / closing part, if the bending fatigue resistance is poor, there is a concern that the conductor breaks during use, and durability and reliability are lacking.
Generally, it is said that a material having higher strength has better fatigue characteristics. Therefore, high-strength aluminum wire may be applied, but the wire harness is required to be easy to handle (installation work on the vehicle body) at the time of installation, so generally the elongation is 10% or more. In many cases, a dull material (annealed material) that can be secured is used.

  Therefore, the aluminum conductor used for the electric wiring body of the moving body has excellent bending fatigue resistance, in addition to the tensile strength required during handling and installation, and the conductivity required to flow a lot of electricity, There is a need for flexible materials that are easy to handle.

  For such demanding applications, pure aluminum systems such as power transmission line aluminum alloy wires (JIS A1060 and JIS A1070) cannot sufficiently withstand repeated bending stresses that occur when doors are opened and closed. Moreover, although the material alloyed by adding various additive elements is excellent in strength, it causes a decrease in conductivity due to a solid solution phenomenon of the additive element in aluminum, and forms an excessive intermetallic compound in aluminum. As a result, disconnection due to the intermetallic compound may occur during wire drawing. For this reason, it is essential to limit and select the additive element and not to disconnect, to prevent a decrease in conductivity, and to improve strength and bending fatigue resistance.

  A typical example of an aluminum conductor used for an electric wiring body of a moving body is that described in Patent Document 1. However, the invention described in Patent Document 1 has an excessively high strength, and an aluminum alloy conductor that can be handled without applying an excessive force is desired.

JP 2010-67591 A

  An object of the present invention is to provide an aluminum alloy conductor having sufficient electrical conductivity and tensile strength, and excellent in bending fatigue resistance and flexibility.

  The present inventors have made various studies and controlled the shape and dislocation density of crystal grains by controlling the degree of wire drawing and the heat treatment conditions and cooling conditions in the final heat treatment process, and have excellent bending fatigue resistance. The present inventors have found that an aluminum alloy conductor having flexibility, strength, and conductivity can be manufactured, and based on this finding, the present invention has been completed.

That is, the said subject was achieved by the following invention.
(1) Fe of 0.01 to 0.4 mass%, Mg of 0.01 mass% to less than 0.3 mass%, Si of 0.01 mass% to less than 0.3 mass%, and Cu of 0.01 to 0 .5 mass%, the balance being Al and inevitable impurities,
An aluminum alloy conductor having a crystal grain flatness of 0.6 to 1.2 and a dislocation density of 25 to 500 / μm ² .
(2) Containing 0.4 to 1.5 mass% Fe, consisting of the balance Al and inevitable impurities,
An aluminum alloy conductor having a crystal grain flatness of 0.6 to 1.2 and a dislocation density of 25 to 500 / μm ² .
(3) Fe is contained in an amount of 0.4 to 1.5 mass%, Mg is 0.01 mass% or more and less than 0.3 mass%, Si is contained in an amount of 0.01 mass% or more and less than 0.3 mass%, and the balance is Al and inevitable impurities. Become
An aluminum alloy conductor having a crystal grain flatness of 0.6 to 1.2 and a dislocation density of 25 to 500 / μm ² .
(4) 0.01 to 1.5 mass% of Fe, 0.3 to 1.0 mass% of Mg, 0.3 to 1.0 mass% of Si, the balance consisting of Al and inevitable impurities,
An aluminum alloy conductor having a crystal grain flatness of 0.6 to 1.2 and a dislocation density of 25 to 500 / μm ² .
(5) Fe containing 0.01 to 1.5 mass%, Mg containing 0.3 to 1.0 mass%, Si containing 0.3 to 1.0 mass%, and Cu containing 0.01 to 0.5 mass% And the balance Al and inevitable impurities,
An aluminum alloy conductor having a crystal grain flatness of 0.6 to 1.2 and a dislocation density of 25 to 500 / μm ² .
(6) The aluminum alloy conductor according to any one of (1) to (5), wherein the aluminum alloy conductor is used for a battery cable, a harness, or a motor lead in a moving body.
(7) The aluminum alloy conductor according to (6), wherein the moving body is an automobile, a train, or an aircraft.
( 8 ) The aluminum alloy conductor according to any one of the items (1) to (5) having a wire diameter of 0.15 to 1.0 mmφ is used as a strand, and a stranded wire obtained by twisting the strands is covered with a resin layer. An aluminum conductive wire characterized by the above.
(9) aluminum conductive wire according to the moving body of the battery cable, shall be the features used as a harness or a motor lead wire (8).
( 10 ) The aluminum conductive wire according to the item ( 9 ), wherein the moving body is an automobile, a train, or an aircraft.

The aluminum alloy conductor of the present invention is excellent in strength and electrical conductivity, and is useful as a battery cable, a harness or a conductor for a motor mounted on a moving body. Examples of the moving body include automobiles, train vehicles, and aircraft. It can also be suitably used for doors, trunks, bonnets and the like that require extremely high bending fatigue resistance.

It is explanatory drawing of the test which measures the frequency | count of repeated fracture | rupture performed in the Example.

  The aluminum alloy conductor of the present invention can have excellent strength, electrical conductivity, flexibility, and bending fatigue resistance by defining the crystal grain shape and dislocation density as follows.

(Crystal shape)
In the aluminum alloy conductor of the present invention, the shape of the crystal grains constituting the wire is defined. The shape of the crystal grain is represented by a numerical value (flatness) given by the maximum length in the direction perpendicular to the drawing direction / the maximum length in the drawing direction. In the present invention, the aspect ratio is 0.6 to 1.2. Since the crystal grains are stretched in the wire drawing direction in the wire drawing step, they approach 0 if after wire drawing. On the contrary, in the heat treatment step, since recrystallized grains are formed, the value is around 1. When the flatness is less than 0.6, the wire material is insufficiently stretched, and the flexibility necessary for handling when attaching the electric wire cannot be obtained. When the aspect ratio is greater than 1.2, the material has anisotropy and the bending fatigue resistance is inferior. The aspect ratio is preferably 0.7 to 1.1, more preferably 0.8 to 1.1.

(Dislocation density)
In the aluminum alloy conductor of the present invention, the dislocation density is 25 to 500 / μm ² . A dislocation is a linear defect in a material. When the dislocation density is less than 25 / μm ² , sufficiently excellent bending fatigue resistance characteristics cannot be obtained. If the dislocation density exceeds 500 / μm ² , linear defects are introduced excessively, which may cause disconnection. Moreover, sufficient flexibility cannot be obtained. The dislocation density is preferably 25 to 300 / μm ² , more preferably 50 to 150 / μm ² .

In order to obtain an aluminum alloy conductor having such a crystal grain shape and dislocation density, the degree of wire drawing of the aluminum alloy conductor, heat treatment conditions and cooling conditions in the final heat treatment step, and the like are controlled as follows: Furthermore, the alloy composition can be achieved by setting as follows. Preferred manufacturing methods and alloy compositions are described below.

(Production method)
The aluminum alloy conductor of the present invention includes [1] melting, [2] casting, [3] hot or cold working (groove roll processing, etc.), [4] wire drawing, [5] heat treatment (intermediate annealing), It can be manufactured through each step of [6] wire drawing, [7] heat treatment (finish annealing), and [8] aging heat treatment.

  Melting is performed in an amount so as to be the concentration of each embodiment of the aluminum alloy composition described above.

  Next, rolling is performed while continuously casting the molten metal in a water-cooled mold using a Properti-type continuous casting and rolling machine in which a cast wheel and a belt are combined to obtain a bar of about 10 mmφ. The casting cooling rate at this time is 1 to 20 ° C./second. Casting and hot rolling may be performed by billet casting, extrusion, or the like.

Next, the surface is peeled to 9 to 9.5 mmφ, and this is drawn. Working ratio is 1 or more and 6 or less. Here working ratio eta is a wire sectional area before drawing A _0, when the wire cross-sectional area after drawing and A _1, represented by _{η = ln (A 0 / A} 1). If the degree of work at this time is too small, the recrystallized grains become coarse during the heat treatment in the next step, and the strength and elongation are remarkably lowered, which may cause disconnection. If it is too large, the wire drawing process becomes difficult, and there may be a problem in terms of quality such as disconnection during the wire drawing process. Although the surface is cleaned by carrying out the peeling of the surface, it may not be carried out.

Intermediate annealing is applied to the cold-drawn workpiece. The intermediate annealing is performed mainly to regain the flexibility of the wire that has been hardened by wire drawing. If the intermediate annealing temperature is too high or too low, the wire is broken in the subsequent wire drawing process, and the wire cannot be obtained. Intermediate annealing temperature is 3 00 to 450 ° C., good Mashiku is 350 to 450 ° C.. The time for the intermediate annealing is 10 minutes or more. This is because if it is less than 10 minutes, the time required for recrystallized grain formation and growth is insufficient, and the flexibility of the wire cannot be regained. Preferably it is 1 to 6 hours. Moreover, as for the average cooling rate from the heat processing temperature at the time of intermediate annealing to 100 degreeC, 0.1-10 degreeC / min is desirable.

Further, wire drawing is performed. Working ratio at this time is 1 to 6. The degree of work greatly affects the formation and growth of recrystallized grains. If the degree of work is too small, the recrystallized grains become coarse during the heat treatment in the next step, and the strength and elongation are significantly reduced, which may cause disconnection. Further, since the dislocation density is insufficient, the bending fatigue resistance is deteriorated. If it is too large, the wire drawing process becomes difficult, and there may be a problem in terms of quality such as disconnection during the wire drawing process. The degree of processing is more preferably 2 or more and 6 or less.

  Finish annealing is performed on the cold-drawn workpiece by continuous heat treatment. The continuous heat treatment can be performed by one of two methods: continuous energization heat treatment and continuous running heat treatment.

The continuous energization heat treatment is performed by annealing with Joule heat generated from itself by passing an electric current through a wire passing through two electrode wheels. It includes the steps of rapid heating and quenching, and the wire can be annealed by controlling the wire temperature and annealing time. Cooling is performed by passing the wire continuously in water or a nitrogen gas atmosphere after rapid heating. When one or both of the wire temperature and the annealing time are too low, the flatness of the crystal grains does not satisfy the predetermined range, and the flexibility required for in-vehicle mounting cannot be obtained. If it is too high, the dislocation density will be lower than the predetermined range, and the bending fatigue resistance will deteriorate. If it is higher, crystal grains are coarsened by over-annealing, and strength and flexibility are lowered. Therefore, in continuous energization heat treatment, if the wire temperature is y (° C.) and the annealing time is x (seconds),
0.03 ≦ x ≦ 0.73, and ^{26x -0.6 + 377 ≦ y ≦ 19x} -0.6 +477
To meet.
The wire temperature y (° C.) represents the temperature immediately before passing through the cooling step, at which the temperature of the wire becomes the highest. y (° C.) is usually in the range of 408 to 633 (° C.).

In the continuous energization heat treatment, the cooling rate until reaching 100 ° C. or lower after the heat treatment is set to 300 ° C./s or higher. This is because if the cooling rate is too slow, the dislocation density is lowered and the bending fatigue resistance may be inferior. Preferably it is 400 degrees C / s or more. The cooling rate V after the heat treatment is the distance L between the point at which the temperature becomes highest in the continuous energization heat treatment and the point L at which the temperature becomes 100 ° C earliest after the continuous energization heat treatment on any line through which the wire passes. _max , 100 ° C.), using the line speed v
V = (T _max −100) v / L (unit: ° C./s)
It was calculated from the following formula. The upper limit is not particularly limited, but the cooling rate after finish annealing is preferably 2000 ° C./s or less.

In the continuous running heat treatment, the wire is continuously passed through an annealing furnace kept at a high temperature and annealed. It includes the steps of rapid heating and rapid cooling, and the wire can be annealed under the control of the annealing furnace temperature and annealing time. Cooling is performed by passing the wire continuously in water or a nitrogen gas atmosphere after rapid heating. When one or both of the annealing furnace temperature and the annealing time are too low, the flatness of the crystal grains does not satisfy the predetermined range, and the flexibility required for mounting on the vehicle cannot be obtained. If it is too high, the dislocation density will be lower than the predetermined range, and the bending fatigue resistance will deteriorate. If it is higher, crystal grains are coarsened by over-annealing, and strength and flexibility are lowered. Therefore, in the continuous running heat treatment, if the annealing furnace temperature is z (° C.) and the annealing time is x (seconds),
1.5 ≦ x ≦ 5, and −50x + 550 ≦ z ≦ −36x + 650
To meet. The annealing furnace temperature z (° C.) is usually in the range of 300 to 596 (° C.).

In the continuous running heat treatment, the cooling rate until reaching 100 ° C. or lower after this heat treatment is determined to be 300 ° C./s or higher. This is because if the cooling rate is too slow, the dislocation density is lowered and the bending fatigue resistance may be inferior. Preferably it is 400 degrees C / s or more. The upper limit is not particularly limited, but the cooling rate after finish annealing is preferably 2000 ° C./s or less. The cooling rate V after the heat treatment is determined by the distance L between the rear end of the annealing furnace in the continuous heat treatment and the point at which the temperature reaches 100 ° C. the first time after the continuous heat treatment, and the temperature (T _max , 100 ° C.), using the line speed v
V = (T _max −100) v / L (unit: ° C./s)
It was calculated from the following formula.

  Next, an aging heat treatment is preferably performed because the bending fatigue resistance is improved depending on the alloy components.

(Alloy composition)
The component constitution of the first embodiment of the present invention is as follows: Fe is 0.01 to 0.4 mass%, Mg is 0.01 mass% or more and less than 0.3 mass%, and Si is 0.01 mass% or more and 0.3 mass%. Less than, Cu is contained in an amount of 0.01 to 0.5 mass%, and the balance is Al and inevitable impurities.

  In the present embodiment, the reason why the Fe content is set to 0.01 to 0.4 mass% is mainly to utilize various effects of the Al—Fe-based intermetallic compound. Fe dissolves only 0.05 mass% in aluminum at 655 ° C., and is even less at room temperature. The remainder is crystallized or precipitated as an intermetallic compound such as Al-Fe, Al-Fe-Si, Al-Fe-Si-Mg, Al-Fe-Cu-Si. This crystallized product or precipitate acts as a crystal grain refining material, and improves strength and bending fatigue resistance. On the other hand, the strength also increases due to the solid solution of Fe. If the Fe content is too small, these effects are insufficient. If the Fe content is too large, the intermetallic compound is coarsened, which decreases the strength and bending resistance. Arise. Moreover, it will be in a supersaturated solid solution state and electrical conductivity will fall. The content of Fe is preferably 0.1 to 0.3 mass%, more preferably 0.15 to 0.3 mass%.

  In the present embodiment, the Mg content is set to 0.01 mass% or more and less than 0.3 mass% because Mg is strengthened by solid solution in the aluminum base material, and a part thereof forms a precipitate with Si. This is because the strength, bending fatigue resistance, and heat resistance can be improved. If the Mg content is too low, the effect is insufficient, and if it is too high, the conductivity is lowered. Moreover, when there is much content of Mg, yield strength will become excess, a moldability and twist property will deteriorate, and workability will worsen. The content of Mg is preferably 0.05 to less than 0.3 mass%, more preferably 0.10 to 0.25 mass%.

  In the present embodiment, the Si content is set to 0.01 mass% or more and less than 0.3 mass%, as described above, Si forms a compound with Mg to improve strength, bending fatigue resistance, and heat resistance. This is to show the function of making it happen. If the Si content is too low, the effect is insufficient, and if it is too high, the conductivity decreases. Moreover, when there is much Si content, precipitation of Si single-piece | unit will arise and it will become easy to cause a disconnection. The Si content is preferably 0.02 to 0.25 mass%, more preferably 0.04 to 0.20 mass%.

  In the present embodiment, the reason why the Cu content is 0.01 to 0.5 mass% is to strengthen and dissolve Cu in the aluminum base material. It also contributes to the improvement of creep resistance, bending fatigue resistance and heat resistance. If the Cu content is too low, the effect is insufficient, and if it is too high, the corrosion resistance and the conductivity are lowered. The Cu content is preferably 0.10 to 0.45 mass%, more preferably 0.20 to 0.40 mass%.

The component constitution of the second embodiment of the present invention contains 0.4 to 1.5 mass% of Fe and consists of the balance Al and inevitable impurities.

  In the second embodiment, the Fe content is set to 0.4 to 1.5 mass% in order to use various effects of the intermetallic compound as described in the first embodiment. If the Fe content is too small, the second embodiment does not contain Cu or Mg, so the tensile strength is low. If it is too much, the intermetallic compound is coarsened, and on the contrary, the strength and flex resistance are lowered. In this case, disconnection occurs from an intermetallic compound. Moreover, it will be in a supersaturated solid solution state and electrical conductivity will fall. The content of Fe is preferably 0.6 to 1.3 mass%, more preferably 0.8 to 1.1 mass%.

The component constitution of the third embodiment of the present invention is as follows. Fe is 0.4 to 1.5 mass%, Mg is 0.01 mass% or more and less than 0.3 mass%, and Si is 0.01 mass% or more and 0.3 mass%. Less than, it consists of the balance Al and inevitable impurities.

In the third embodiment, the content of Fe is larger than that of the alloy composition of the first embodiment described above, and Cu is not contained. The reason why the Fe content is set to 0.4 to 1.5 mass% is mainly to use various effects of the Al—Fe-based intermetallic compound. The effect is as described in the first embodiment. If the Fe content is too low, the third embodiment does not contain Cu, so the tensile strength is low. If it is too high, the intermetallic compound is coarsened, and on the contrary, the strength and flex resistance are lowered. The intermetallic compound is the starting point and disconnection occurs. Moreover, it will be in a supersaturated solid solution state and electrical conductivity will fall. The content of Fe is preferably 0.6 to 1.3 mass%, more preferably 0.8 to 1.1 mass%.
Other alloy compositions and their actions are the same as in the first embodiment described above.

The component constitution of the fourth embodiment of the present invention includes Fe of 0.01 to 1.5 mass%, Mg of 0.3 to 1.0 mass%, Si of 0.3 to 1.0 mass%, It is an aluminum alloy conductor composed of the balance Al and inevitable impurities.

  The reason why the Fe content is set to 0.01 to 1.5 mass% in the present embodiment is to use various effects of the intermetallic compound as described in the first embodiment. If the Fe content is too small, the effect is insufficient. If the Fe content is too large, the intermetallic compound is coarsened, and on the contrary, the strength and bending resistance are lowered. Moreover, it will be in a supersaturated solid solution state and electrical conductivity will fall. The Fe content is preferably 0.15 to 1.1 mass%, more preferably 0.15 to 0.9 mass%.

  The reason why the Mg content is 0.3 to 1.0 mass% is to precipitate a large amount of Mg-Si-based precipitates and to improve the strength while keeping the electrical conductivity appropriately. If the content of Mg is too small, an increase in strength cannot be expected so much, and if it is too large, the conductivity is lowered. Moreover, when there is much content of Mg, yield strength will become excess, a moldability and twist property will deteriorate, and workability will worsen. The Mg content is preferably 0.4 to 0.9 mass%, more preferably 0.5 to 0.8 mass%.

The reason why the Si content is set to 0.3 to 1.0 mass% is to increase the strength of the Mg-Si-based precipitates by depositing a large amount of Mg-Si-based precipitates and maintaining the conductivity appropriately. If the Si content is too small, an increase in strength cannot be expected so much, and if it is too much, the conductivity decreases. Moreover, when there is much Si content, precipitation of Si single-piece | unit will arise and it will become easy to cause a disconnection. The Si content is preferably 0.4 to 0.9 mass%, more preferably 0.5 to 0.8 mass%.
It is.

The component constitution of the fifth embodiment of the present invention is as follows: Fe is 0.01 to 1.5 mass%, Mg is 0.3 to 1.0 mass%, Si is 0.3 to 1.0 mass%, Cu Is an aluminum alloy conductor containing 0.01 to 0.5 mass% and the balance Al and inevitable impurities.

  The alloy composition and its action of the fifth embodiment are the same as those of the fourth embodiment for Fe, Mg, and Si, and are the same as those of the first embodiment for Cu.

  Inevitable impurities are contained levels included in the manufacturing process. Inevitable impurities cause a slight decrease in electrical conductivity, but they are included in the manufacturing process, so it is necessary to consider the decrease in electrical conductivity. Inevitable impurities include, for example, Si of 0.10 mass% or less, Cu of 0.005 mass% or less, Mn of 0.005 mass% or less, and the like. These elements referred to JIS H 2110.

  The wire diameter of the conductor of the aluminum alloy wire of the present invention is not particularly limited and can be appropriately determined according to the application, but is preferably 0.15 to 1.0 mmφ, more preferably 0.20 to 0.8 mmφ. . One of the advantages of the wire rod of the present invention is that it can be used as an aluminum alloy wire by thinning it with a single wire, but it can also be used by bundling a plurality of wires (as a stranded wire).

  The present invention will be described in detail based on the following examples. In addition, this invention is not limited to the Example shown below.

Examples 1-13, Comparative Examples 1-5
Rolling is carried out while continuously casting the molten metal in a water-cooled mold using a Properti type continuous casting and rolling machine so that Fe, Mg, Si, Cu, and Al are in the amounts (mass%) shown in Table 1. The bar was about 10 mmφ. The casting cooling rate at this time is 1 to 20 ° C./second.
Next, the surface was peeled to about 9.5 mmφ, and this was drawn so as to obtain a predetermined degree of processing. Next, this cold-drawn workpiece was subjected to intermediate annealing at a temperature of 300 to 450 ° C. for 0.5 to 4 hours, and further drawn to a predetermined wire diameter.

The correspondence between the wire drawing history and the processing degree η before continuous heat treatment is as follows.
9.5 mmφ → 0.55 mmφ → intermediate annealing → 0.37 mmφ (η = 0.8)
9.5 mmφ → 0.54 mmφ → intermediate annealing → 0.31 mmφ (η = 1.1)
9.5 mmφ → 0.9 mmφ → Intermediate annealing → 0.31 mmφ (η = 2.1)
9.5 mmφ → 1.5 mmφ → intermediate annealing → 0.31 mmφ (η = 3.2)
9.5 mmφ → 2.6 mmφ → intermediate annealing → 0.43 mmφ (η = 3.6)
9.5 mmφ → 2.6 mmφ → intermediate annealing → 0.37 mmφ (η = 3.9)
9.5 mmφ → 2.6 mmφ → intermediate annealing → 0.31 mmφ (η = 4.3)
9.5 mmφ → 5.7 mmφ → intermediate annealing → 0.31 mmφ (η = 5.8)
The wire drawn to a working degree of 6 or more was drawn from 9.5 mmφ and disconnected at a wire diameter (0.43 mmφ) at a working degree of 6.2.

  Next, heat treatment was performed under the conditions shown in Table 1. In the continuous energization heat treatment, the wire temperature y (° C.) immediately before passing through the water where the temperature of the wire becomes the highest was measured with a fiber-type radiation thermometer (manufactured by Japan Sensor). In the continuous running heat treatment, the annealing furnace temperature z (° C.) is described. Further, the point at which the temperature reached 100 ° C. the earliest after the heat treatment was measured, and the cooling rate was calculated.

  Each characteristic was measured with the method described below about the produced wire of each Example and a comparative example. The results are shown in Table 1.

(A) Flatness of crystal grains A longitudinal section of a specimen cut out in parallel with the wire drawing direction was filled with a resin, subjected to electropolishing after mechanical polishing. The electrolytic polishing conditions are: an ethanol solution containing 20% perchloric acid as the polishing liquid, a liquid temperature of 0 to 5 ° C., a voltage of 10 V, a current of 10 mA, and a time of 30 to 60 seconds. Next, in order to obtain crystal grain contrast, anodic finishing was performed using 2% borohydrofluoric acid under the conditions of a voltage of 20 V, a current of 20 mA, and a time of 2 to 3 minutes. This structure was photographed with an optical microscope of 200 to 400 times, and the flatness of crystal grains was measured. The flatness is calculated as the maximum length in the direction perpendicular to the drawing direction / the maximum length in the drawing direction for one crystal grain, and the average of 15 arbitrarily selected crystal grains is calculated. did. The longitudinal section was embedded in the resin so that it passed through the center of the wire, specifically, the length in the direction perpendicular to the wire drawing direction was 0-10% with respect to the diameter of the wire.
(B) Dislocation density The wires of Examples and Comparative Examples were thinned by the FIB method, and three arbitrary 1 μm ² fields of view were photographed using a transmission electron microscope (TEM). The dislocation density ρ was measured by a method called the Ham method. In other words, 10 parallel lines are drawn vertically and horizontally on the photographed photo, and the total length L (μm) of the lines and the number N at which dislocations intersect, and the sample thickness t (μm),
ρ = 2N / Lt (number of units / μm ² )
The average of n3 was calculated from the formula of When the value (%) obtained by subtracting the minimum value from the maximum value of the dislocation density obtained by the measurement of n3 and dividing by the maximum value and multiplying by 100 differs by 25% or more, take five pictures and The dislocation density was calculated by the same method, and the average of n5 was obtained. Since dislocations appear and disappear depending on the diffraction conditions, when observing an arbitrary field of view, tilt the sample in the x-axis or y-axis direction, which is the sample axis, and observe while changing the diffraction conditions. A field of view where dislocations appeared was selected and photographed. In the present example and the comparative example, the sample thickness of the thin film was prepared by setting the sample thickness to about 0.15 μm in all samples by the FIB method.
(C) Tensile strength (TS) and flexibility (tensile elongation at break)
Three each were tested according to JIS Z 2241 and the average value was determined. The tensile strength was 80 MPa or more and less than 240 MPa. For the flexibility, the tensile elongation at break was 10% or more.
(D) Conductivity (EC)
Three specific resistances were measured using a four-terminal method in a constant temperature bath holding a 300 mm long test piece at 20 ° C. (± 0.5 ° C.), and the average conductivity was calculated. The distance between the terminals was 200 mm. The electrical conductivity is not particularly limited, but is preferably 50% IACS or more, and more preferably 54% or more.
(E) Number of repeated fractures As a standard for bending fatigue resistance, the strain amplitude at room temperature was ± 0.17%. Bending fatigue resistance varies with strain amplitude. When the strain amplitude is large, the fatigue life is shortened, and when the strain amplitude is small, the fatigue life is lengthened. Since the strain amplitude can be determined by the wire diameter of the wire rod 1 and the bending radii of the bending jigs 2 and 3 shown in FIG. 1, the wire diameter of the wire rod 1 and the bending radii of the bending jigs 2 and 3 are arbitrarily set and bent. It is possible to conduct a fatigue test.
The number of repeated ruptures by repeatedly bending using a jig that gives a bending strain of 0.17% using a double-bending fatigue tester manufactured by Fujii Seiki Co., Ltd. (currently Fujii Co., Ltd.) Was measured. The number of repeated ruptures was measured four by four and the average value was determined. As shown in the explanatory view of FIG. 1, the wire 1 was inserted with a gap of 1 mm between the bending jigs 2 and 3, and repeatedly moved in such a manner as to be along the jigs 2 and 3. One end of the wire was fixed to a holding jig 5 so that it could be bent repeatedly, and a weight 4 of about 10 g was hung from the other end. Since the holding jig 5 moves during the test, the wire 1 fixed to the holding jig 5 also moves and can be bent repeatedly. The repetition is performed under the condition of 1.5 Hz (1.5 reciprocations per second), and when the wire specimen 1 breaks, the weight 4 falls and stops counting. The number of repeated fractures is preferably 100,000 times or more, more preferably 120,000 times or more, and further preferably 150,000 times or more.

Comparative Example No. Examples 1 to 5 are examples in which the aluminum alloy conductor defined by the present invention was not obtained depending on the production conditions of the aluminum alloy. Comparative Example No. In No. 1, since the degree of wire drawing was too small, the tensile strength, tensile elongation at break, and repeated breaking characteristics were poor. Comparative Example No. In No. 2, since the degree of wire drawing was too large, the wire was broken during wire drawing. Comparative Example No. In No. 3, since the temperature of the continuous energization heat treatment was too low, the tensile elongation at break was poor. Comparative Example No. In No. 4, since the temperature of the continuous energization heat treatment was too high, the tensile strength, tensile elongation at break, and repeated fracture characteristics were poor. Comparative Example No. In No. 5, since the cooling rate was too low, the repeated fracture characteristics were poor.
In contrast, in Examples Nos. 1 to 13, aluminum alloy conductors excellent in tensile strength, electrical conductivity, tensile fracture elongation (flexibility), and repeated fracture characteristics (flexural fatigue resistance) were obtained.

1 Test piece (wire)
2, 3 Bending jig 4 Weight 5 Holding jig

Claims (10)

Fe is 0.01 to 0.4 mass%, Mg is 0.01 mass% or more and less than 0.3 mass%, Si is 0.01 mass% or more and less than 0.3 mass%, and Cu is 0.01 to 0.5 mass%. Containing, balance Al and inevitable impurities,
An aluminum alloy conductor having a crystal grain flatness of 0.6 to 1.2 and a dislocation density of 25 to 500 / μm ² . Fe containing 0.4 to 1.5 mass%, consisting of the balance Al and inevitable impurities,
An aluminum alloy conductor having a crystal grain flatness of 0.6 to 1.2 and a dislocation density of 25 to 500 / μm ² . Fe containing 0.4 to 1.5 mass%, Mg containing 0.01 mass% or more and less than 0.3 mass%, Si containing 0.01 mass% or more and less than 0.3 mass%, the balance consisting of Al and inevitable impurities,
An aluminum alloy conductor having a crystal grain flatness of 0.6 to 1.2 and a dislocation density of 25 to 500 / μm ² . Fe containing 0.01 to 1.5 mass%, Mg containing 0.3 to 1.0 mass%, Si containing 0.3 to 1.0 mass%, the balance consisting of Al and inevitable impurities,
An aluminum alloy conductor having a crystal grain flatness of 0.6 to 1.2 and a dislocation density of 25 to 500 / μm ² . Fe containing 0.01 to 1.5 mass%, Mg 0.3 to 1.0 mass%, Si 0.3 to 1.0 mass%, Cu 0.01 to 0.5 mass%, the balance Consists of Al and inevitable impurities,
An aluminum alloy conductor having a crystal grain flatness of 0.6 to 1.2 and a dislocation density of 25 to 500 / μm ² .   The aluminum alloy conductor according to any one of claims 1 to 5, wherein the aluminum alloy conductor is for a battery cable, a harness, or a motor lead in a moving body.   The aluminum alloy conductor according to claim 6, wherein the moving body is an automobile, a train, or an aircraft.   The aluminum alloy conductor according to any one of claims 1 to 5 having a wire diameter of 0.15 to 1.0 mmφ is used as a strand, the strands are twisted together, and the stranded wire is covered with a resin layer. Aluminum conductive wire. The aluminum conductive wire according to claim 8, wherein the aluminum conductive wire is used as a battery cable, a harness, or a motor lead in a moving body. The aluminum conductive wire according to claim 9 , wherein the moving body is an automobile, a train, or an aircraft.

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