JP4986253B2 - Aluminum alloy conductor - Google Patents

Description

  The present invention relates to an aluminum alloy conductor used as a conductor of an electric wiring body.

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 conductivity of aluminum is about 2/3 of copper (pure aluminum is about 66% IACS when pure copper is used as the standard for 100% IACS). In order to pass the same current as a pure copper conductor, the cross-sectional area of a pure aluminum conductor needs to be about 1.5 times that of a pure copper conductor, but the weight is still about half that of copper. is there.
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 several problems in using aluminum as a conductor of an electric wiring body of a moving body, and one is improvement of bending fatigue resistance. The reason why the aluminum conductor used for the electric wiring body of the moving body is required to have bending fatigue resistance is that the wire harness attached to the 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 such as opening and closing of a door even at a low load that does not break at a single load, fatigue failure that breaks at a certain number of repetitions occurs. When the aluminum conductor is used for an opening / closing portion, if the bending fatigue resistance is poor, there is a concern that the conductor may break during use, resulting in a problem of lack of durability and reliability.
Generally, it is said that a material having higher strength has better fatigue characteristics. Therefore, a high-strength aluminum conductor may be applied. However, since the wire harness is required to be easily handled (installation work on the vehicle body) at the time of installation, generally flexibility can be secured. Dull material (annealed material) is often used.

  Therefore, the aluminum conductor used for the electric wiring body of the moving body has excellent bending fatigue resistance in addition to the strength and flexibility required for handling and mounting, and the conductivity required to flow a lot of electricity. Materials are needed.

  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. Although alloying with various additive elements is excellent in strength, it causes a decrease in electrical conductivity due to the solid solution phenomenon of the additive elements in aluminum, decreases flexibility, and excessive metals in aluminum. It was a problem that a wire breakage caused by an intermetallic compound occurred during wire drawing by forming an intermetallic compound. Therefore, it is essential to limit and select the additive element and not to disconnect, to prevent a decrease in conductivity and a decrease in flexibility, and to improve strength and bending fatigue resistance.

Typical examples of the aluminum conductor used in the electric wiring body of the moving body include those described in Patent Documents 1 to 4. However, as described below, the inventions described in any of the patent documents have further problems to be solved.
Since the invention of Patent Document 1 does not perform finish annealing, it cannot secure the flexibility required for the mounting work on the vehicle body.
The invention of Patent Document 2 discloses finish annealing, and the conditions are such that the intermetallic compound can be controlled so as to improve the bending fatigue resistance and conductivity while maintaining excellent flexibility. Is different.
In the invention of Patent Document 3, since the amounts of Mg and Si are large, the intermetallic compound cannot be appropriately controlled, which causes disconnection during wire drawing.
The invention of Patent Document 4 is a technique that is being replaced with an alternative product from the viewpoint of environmental load because it contains antimony (Sb) as an additive element.

JP 2006-19163 A JP 2006-253109 A JP 2008-112620 A Japanese Patent Publication No.55-45626

  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, flexibility, and the like.

  The inventors of the present invention have made various studies, and by controlling the production conditions such as casting cooling rate, intermediate annealing, and finish annealing for the aluminum alloy to which a specific additive element is added, the particle size and area of two kinds of intermetallic compounds. It has been found that an aluminum alloy conductor having excellent bending fatigue resistance, strength, flexibility and electrical conductivity can be produced by controlling the rate, and the present invention has been completed based on this finding.

That is, the present invention provides the following solutions.
(1) An aluminum alloy conductor containing Fe in an amount of 0.4 to 0.9 mass% and comprising the balance Al and inevitable impurities,
Two types of intermetallic compounds A and B exist in the conductor,
The particle size of the intermetallic compound A is in the range of 0.1 μm to 2 μm,
The particle size of the intermetallic compound B is in the range of 0.03 μm or more and less than 0.1 μm,
The area ratio a of the intermetallic compound A and the area ratio b of the intermetallic compound B in an arbitrary range in the conductor satisfy 1% ≦ a ≦ 6% and 1% ≦ b ≦ 5%, respectively. Aluminum alloy conductor characterized by
(2) An aluminum alloy conductor containing 0.4 to 0.9 mass% of Fe and 0.01 to 0.4 mass% of Zr, the balance being Al and inevitable impurities,
Two types of intermetallic compounds A and B exist in the conductor,
The particle size of the intermetallic compound A is in the range of 0.1 μm to 2 μm,
The particle size of the intermetallic compound B is in the range of 0.03 μm or more and less than 0.1 μm,
The area ratio a of the intermetallic compound A and the area ratio b of the intermetallic compound B in an arbitrary range in the conductor satisfy 1% ≦ a ≦ 6% and 1% ≦ b ≦ 7.5%, respectively. An aluminum alloy conductor characterized by:
(3) The continuous grain heat treatment including rapid heating and rapid cooling processes is performed at the end of the manufacturing process of the conductor, so that the crystal grain size in the vertical cross section in the wire drawing direction is 1 to 15 μm (1) or The aluminum alloy conductor according to (2).
(4) The aluminum alloy conductor according to any one of (1) to (3), wherein the tensile strength is 80 MPa or more and the electrical conductivity is 60% IACS or more.
(5) The aluminum alloy conductor according to any one of (1) to (4), which has a tensile elongation at break of 10% or more.
(6) The aluminum alloy conductor according to any one of (1) to (5), which has a recrystallized structure.
(7) The aluminum alloy conductor according to any one of (1) to (6), wherein the conductor is used as a battery cable, a harness, or a wire for a motor in a moving body.
(8) The aluminum alloy conductor according to any one of (1) to (7), wherein the conductor is used in a vehicle, a train, or an aircraft.

  The aluminum alloy conductor of the present invention is excellent in strength, flexibility and electrical conductivity, and is useful as a battery cable, harness or motor conductor mounted on a moving body, doors and trunks that require excellent bending fatigue resistance, It can be suitably used for a bonnet or the like.

  The above and other features and advantages of the present invention will become more apparent from the following description, with reference where appropriate to the accompanying drawings.

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

A preferred first embodiment of the present invention is an aluminum alloy conductor containing Fe in an amount of 0.4 to 0.9 mass% and comprising the balance Al and inevitable impurities,
Two types of intermetallic compounds A and B exist in the conductor,
The particle size of the intermetallic compound A is in the range of 0.1 μm to 2 μm,
The particle size of the intermetallic compound B is in the range of 0.03 μm or more and less than 0.1 μm,
The area ratio a of the intermetallic compound A and the area ratio b of the intermetallic compound B in an arbitrary range in the conductor satisfy 1% ≦ a ≦ 6% and 1% ≦ b ≦ 5%, respectively.

  In the present embodiment, the reason why the Fe content is set to 0.4 to 0.9 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 crystallizes or precipitates as an intermetallic compound such as Al—Fe or Al—Fe—Si. This crystallized product or precipitate acts as a crystal grain refining material, and improves strength and bending fatigue resistance. If the Fe content is too small, these effects are insufficient, and if it is too much, the crystallized material becomes coarse and the wire drawing workability is poor, the desired bending fatigue resistance cannot be obtained, and the flexibility also decreases. . Moreover, it will be in a supersaturated solid solution state and electrical conductivity will also fall. The Fe content is preferably 0.4 to 0.8 mass%, more preferably 0.5 to 0.7 mass%.

The second preferred embodiment of the present invention is an aluminum alloy conductor containing 0.4 to 0.9 mass% of Fe and 0.01 to 0.4 mass% of Zr, and the balance being Al and inevitable impurities. And
Two types of intermetallic compounds A and B exist in the conductor,
The particle size of the intermetallic compound A is 0.1 μm or more and 2 μm or less,
The particle size of the intermetallic compound B is 0.03 μm or more and less than 0.1 μm,
The area ratio a of the intermetallic compound A and the area ratio b of the intermetallic compound B satisfy 1% ≦ a ≦ 6% and 1% ≦ b ≦ 7.5%.

In the second embodiment, the alloy composition contains 0.01 to 0.4 mass% of Zr in addition to the alloy composition of the first embodiment described above. Zr forms an intermetallic compound with Al, and also forms a solid solution in Al, contributing to the improvement of the strength and heat resistance of the aluminum alloy conductor. If the Zr content is too small, the effect cannot be expected. If the Zr content is too large, the melting temperature becomes high and it becomes difficult to form a wire. In addition, the conductivity and flexibility are lowered, and the bending fatigue resistance is also deteriorated. The content of Zr is preferably 0.1 to 0.35 mass%, more preferably 0.15 to 0.3 mass%.
Other alloy compositions and their actions are the same as in the first embodiment described above.

  In addition to the above components, the aluminum alloy conductor of the present invention has desired excellent bending fatigue resistance, strength, flexibility and electrical conductivity by defining the size (particle diameter) and area ratio of the intermetallic compound. An aluminum alloy conductor can be obtained.

(Dimensions (particle diameter) and area ratio of intermetallic compounds)
As shown in the first and second embodiments, the present invention contains two kinds of intermetallic compounds having different particle diameters at a predetermined area ratio. Here, an intermetallic compound is particles, such as a crystallized substance and a precipitate, which exist in crystal grains. The crystallized material is mainly formed during melt casting, and the precipitate is formed by intermediate annealing and finish annealing, for example, particles such as Al—Fe, Al—Fe—Si, and Al—Zr. The area ratio represents the ratio of intermetallic compounds contained in the present alloy in terms of area, and can be calculated as described in detail below based on a photograph observed by TEM.
The intermetallic compound A is mainly composed of Al—Fe, and a part thereof includes Al—Fe—Si, Al—Zr and the like. These intermetallic compounds work as crystal grain refiners and improve strength and bending fatigue resistance. The reason why the area ratio a of the intermetallic compound A is 1% ≦ a ≦ 6% is that these effects are insufficient if the amount is too small, and if the amount is too large, disconnection is likely to occur due to the intermetallic compound. Flexural fatigue characteristics cannot be obtained and flexibility is also reduced.
The intermetallic compound B is mainly composed of Al—Fe—Si and Al—Zr. These intermetallic compounds improve strength and bending fatigue resistance by precipitation. The area ratio b of the intermetallic compound B is set to 1% ≦ b ≦ 5% in the first embodiment and 1% ≦ b ≦ 7.5% in the second embodiment. This is because it is insufficient, and if it is too much, it causes disconnection due to excessive precipitation. Also, flexibility is reduced.

  In the first and second embodiments of the present invention, in the intermetallic compounds A and B having two types of dimensions, in order to set the area ratio to the above value, it is necessary to set each alloy composition within the above-described range. is there. And it is realizable by controlling appropriately a casting cooling rate, intermediate annealing temperature, finish annealing conditions, etc.

  The casting cooling rate is an average cooling rate from the start of solidification of the aluminum alloy ingot to 200 ° C. As a method for changing the cooling rate, for example, the following three methods can be cited. That is, (1) change the size (thickness) of the iron mold, (2) provide a water cooling mold on the lower surface of the mold and forcibly cool (the cooling speed also changes by changing the amount of water), (3) the amount of casting of the molten metal Change. If the casting cooling rate is too slow, the Al-Fe-based crystallized product becomes coarse, and the target structure cannot be obtained, and cracking is likely to occur. If it is too fast, an excessive solid solution of Fe occurs, the target structure cannot be obtained, and the electrical conductivity is lowered. In some cases, casting cracks can also occur. The casting cooling rate is usually 1 to 20 ° C./second, preferably 5 to 15 ° C./second.

  The intermediate annealing temperature is a temperature at which heat treatment is performed during wire drawing. 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 low, the recrystallization is insufficient and the yield strength becomes excessive, so that flexibility cannot be secured, and there is a high possibility that the wire will not be obtained due to the subsequent wire drawing. When too high, it will be in an over-annealed state, recrystallization grain coarsening will occur and flexibility will fall remarkably, and the possibility that a wire will not be obtained by causing wire breakage in the subsequent wire drawing will increase. The intermediate annealing temperature is usually 300 to 450 ° C, preferably 350 to 450 ° C. The time for the intermediate annealing is usually 30 minutes or more. This is because if it is less than 30 minutes, the time required for the formation and growth of recrystallized grains is insufficient, and the flexibility of the wire cannot be recovered. Preferably it is 1 to 6 hours. The average cooling rate from the heat treatment temperature during intermediate annealing to 100 ° C. is not particularly specified, but is preferably 0.1 to 10 ° C./min.

The finish annealing is performed, for example, by continuous energization heat treatment in which annealing is performed by Joule heat generated from itself by passing an electric current through a wire that passes through two electrode wheels. The continuous energization heat treatment includes rapid heating and rapid cooling steps, and can be annealed by controlling the wire temperature and time. Cooling is performed by passing the wire continuously through water after rapid heating. If the wire temperature during annealing is too low or too high, or if one or both of the annealing times are too short or too long, the desired structure cannot be obtained. Furthermore, if the wire temperature during annealing is too low, if one or both of the annealing time is too short, the necessary flexibility when mounting on the vehicle is not obtained, if the wire temperature during annealing is too high, In one or both of cases where the annealing time is too long, the strength is lowered and the bending fatigue resistance is also deteriorated. That is, the wire temperature y (° C.), the use of equations represented by annealing time x (seconds), ^26x -0.6 + 377 within a range of 0.03 ≦ x ≦ 0.55 ≦ y ≦ 19x -0.6 It is necessary that the annealing conditions satisfy +477. The wire temperature represents the temperature immediately before passing through the water, which is the highest in the wire.
Note that finish annealing includes rapid heating and quenching processes in addition to continuous energization heat treatment, for example, running annealing in which the wire continuously anneals through an annealing furnace maintained at a high temperature, and the wire in the magnetic field. It may be induction heating that passes and anneals continuously. The annealing conditions are not the same as those for continuous energization heat treatment because the atmosphere and heat transfer coefficient are different, but even in the case of running annealing and induction heating, including these rapid heating and quenching processes, the prescribed intermetallic compound By appropriately controlling the finish annealing conditions (thermal history) with reference to the annealing conditions in the continuous energization heat treatment as a representative example so that the aluminum alloy conductor of the present invention having a precipitation state can be obtained, The aluminum alloy conductor of the invention can be produced.

(Crystal grain size)
In the present invention, the crystal grain size in the vertical cross section in the wire drawing direction of the aluminum alloy conductor is 1 to 15 μm. The reason for this is that if the particle size is too small, the partially recrystallized structure remains and the tensile elongation at break is remarkably reduced, and if it is too large, a coarse structure is formed and the deformation behavior becomes non-uniform, and similarly the tensile break This is because the elongation is lowered and the strength is significantly lowered. The crystal grain size is preferably 1 to 10 μm.

(Tensile strength and conductivity)
The aluminum alloy conductor of the present invention has a tensile strength (TS) of 80 MPa or more and a conductivity of 60% IACS or more, preferably a tensile strength of 80 to 150 MPa and a conductivity of 60 to 65% IACS, more preferably tensile. The strength is 100 to 140 MPa and the conductivity is 61 to 64% IACS.
Tensile strength and electrical conductivity have contradictory properties. The higher the tensile strength, the lower the electrical conductivity, and conversely, pure aluminum with a low tensile strength has a higher electrical conductivity. When an aluminum alloy conductor is considered, if the tensile strength is less than 80 MPa, it is weak including handling, and it is difficult to use it as an industrial conductor. When used for a power line, a high current of several tens of A (amperes) flows, so that the conductivity is desirably 60% IACS or more.

(Flexibility)
The aluminum alloy conductor of the present invention has sufficient flexibility. This can be obtained by performing the above-described finish annealing. In the present invention, the tensile elongation at break is used as an index of the flexibility of the aluminum alloy conductor, preferably 10% or more. The reason for this is that if the tensile elongation at break is too small, it is difficult to handle the wiring body (for example, mounting work on the vehicle body) as described above, and if it is too large, the strength is insufficient and the wiring is weak and broken. This is because it may cause The tensile elongation at break is more preferably 20 to 50%, still more preferably 25 to 45%.

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

[1] Melting In order to obtain the aluminum alloy composition of the present invention, Fe and Al, or Fe, Zr and Al are melted in such amounts that a desired concentration is obtained.

[2] Casting and [3] Hot or cold processing (groove roll processing, etc.)
Next, for example, using a Properti type continuous casting and rolling machine in which a casting wheel and a belt are combined, rolling is performed while continuously casting the molten metal in a water-cooled mold to obtain a rod of about 10 mmφ. The casting cooling rate at this time is usually 1 to 20 ° C./second as described above. Casting and hot rolling may be performed by billet casting with a casting cooling rate of 1 to 20 ° C./second, an extrusion method, or the like.

[4] Wire drawing Next, the surface is peeled to 9 to 9.5 mmφ, and this is wire drawn. Here, when the wire cross-sectional area before wire drawing is A ₀ , and the wire cross-sectional area after wire drawing is A ₁ , the degree of work represented by η = ln (A ₀ / A ₁ ) is 1 or more and 6 The following is desirable. If it is less than 1, the recrystallized grains become coarse during the heat treatment in the next step, and the strength and tensile elongation at break are remarkably reduced, which may cause disconnection. If it exceeds 6, work hardening becomes too difficult to draw, and there is a problem in terms of quality, such as disconnection during drawing. Although the surface of the wire is peeled to clean the surface, it need not be performed.

[5] Heat treatment (intermediate annealing)
Intermediate annealing is applied to the cold-drawn workpiece. The conditions for the intermediate annealing are usually 300 to 450 ° C. for 30 minutes or more as described above.

[6] Wire drawing Further wire drawing is performed. Also in this case, the degree of processing is preferably 1 or more and 6 or less for the reason described above.

[7] Heat treatment (finish annealing)
Finish annealing is performed on the cold-drawn workpiece by continuous energization heat treatment. As described above, when the annealing conditions are expressed by the wire temperature y (° C.) and the annealing time x (seconds), in the range of 0.03 ≦ x ≦ 0.55, 26x− ^0.6 + 377 ≦ y ≦ 19x ^-0.6 +477 is satisfied.

  The aluminum alloy conductor of the present invention produced by heat treatment as described above has a recrystallized structure. The recrystallized structure is a structure state composed of crystal grains with few lattice defects such as dislocations introduced by plastic working. By having a recrystallized structure, tensile elongation at break and electrical conductivity are recovered, and sufficient flexibility can be obtained.

  The invention is explained in more detail on the basis of the following examples. In addition, this invention is not limited to the Example shown below.

Examples 1-13, Comparative Examples 101-110, 201
Continuous casting of Fe and Al or Fe, Zr and Al in the amounts (mass%) shown in Table 1-1 and Table 2-1 in a mold in which the molten metal is cooled with water using a Properti type continuous casting mill. Rolling was performed while making a rod of about 10 mmφ. The casting cooling rate at this time is 1 to 20 ° C./second (including 0.2 ° C./second and 50 ° C./second in the comparative example).
Next, the surface is peeled to 9 to 9.5 mmφ, and this is drawn to 2.6 mmφ. Next, as shown in Table 1-1 and Table 2-1, the cold-drawn processed material was heated at a temperature of 300 to 450 ° C. (including 200 ° C. and 550 ° C. in the comparative example) for 0.5 to 4 hours ( (Comparative example includes 0.1 hour), and in Examples 1 to 11, Comparative Examples 101 to 110 and 201, up to 0.31 mmφ, Example 12 to 0.37 mmφ, and Example 13 Drawing was performed to 0.43 mmφ.
Finally, continuous energization heat treatment was performed as finish annealing at temperatures of 461 to 621 ° C. (including 432, 435, 450, 460, and 623 ° C. in the comparative example) at a time of 0.03 to 0.54 seconds. The temperature was measured with a fiber-type radiation thermometer (manufactured by Japan Sensor Co., Ltd.) immediately above the water surface where the temperature of the wire became highest.

  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 1-2 and Table 2-2.

(A) Crystal grain size The cross section of the specimen cut out perpendicular to the wire drawing direction was filled with resin, and after mechanical polishing, electrolytic polishing was performed. 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 particle size was measured by the crossing method. Specifically, an average particle size was obtained by arbitrarily drawing a straight line on the photographed photo, and measuring the number of intersections of the length of the straight line and the grain boundary. The particle size was evaluated by changing the length and number of lines so that 50 to 100 particles could be counted.
(B) Identification of intermetallic compound, dimensions (particle diameter), and area ratio The wires of Examples and Comparative Examples were made into thin films by an electrolytic polishing thin film method (twin jet polishing method), and a transmission electron microscope (TEM) was used. An arbitrary range was observed at a magnification of 6000 to 30000 times. Next, using an energy dispersive X-ray detector (EDX), an electron beam was focused on the intermetallic compound, and Al—Fe, Al—Fe—Si, and Al—Zr intermetallic compounds were detected.
The size of the intermetallic compound was judged from the scale of the photographed photo, and the shape was calculated by converting it into an equivalent volume sphere. The area ratios a and b of the intermetallic compound are set based on the photographed images, and a range in which about 5 to 10 for the intermetallic compound A and 20 to 50 for the intermetallic compound B can be counted, The area of the intermetallic compound was calculated from the size and number of each intermetallic compound, and the area of each intermetallic compound was divided by the area of the range to be counted.
The area ratio is calculated by using the sample thickness of the thin piece as a reference thickness of 0.15 μm. If the sample thickness is different from the reference thickness, convert the sample thickness to the reference thickness, that is, by multiplying the area ratio calculated based on the photographed (reference thickness / sample thickness) The area ratio can be calculated. In this example and the comparative example, the sample thickness was calculated by observing the interval of the equal thickness stripes observed from the photograph, and was about 0.15 μm in all the samples.
(C) Tensile strength and tensile elongation at break Three pieces each were tested according to JIS Z 2241, and the average value was obtained.
(D) Conductivity In a constant temperature bath holding a test piece having a length of 300 mm at 20 ° C. (± 0.5 ° C.), three specific resistances were measured using the four probe method, and the average conductivity was measured. Calculated. The distance between the terminals was 200 mm.
(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.
By using a double-bending bending fatigue tester manufactured by Fujii Seiki Co., Ltd. (currently Fujii Co., Ltd.) and using a jig that gives a bending strain of ± 0.17% to the wire, repeated bending is performed. The number of return breaks 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.
If the number of times of opening and closing per day is 10 and the use for 10 years is assumed, the number of times of opening and closing is 36500 (calculated as 365 days a year). The actually used electric wire is not a single wire but has a stranded wire structure, and since the coating process is performed, the burden on the electric wire conductor becomes a fraction. The number of repeated fractures of 50000 times or more that can ensure sufficient bending fatigue resistance as an evaluation value for a single wire is preferred, and more preferably 70000 times or more.

The following is understood from the results of Table 1-1, Table 1-2, Table 2-1, and Table 2-2.
In Comparative Examples 101 to 103, the additive component of the aluminum alloy is outside the scope of the present invention. In Comparative Example 101, since Fe is too small, intermetallic compounds A and B are reduced, and the tensile strength and the number of repeated fractures are poor. In Comparative Example 102, since there is too much Fe, intermetallic compounds A and B increase, and the number of repeated fractures and electrical conductivity are poor. In Comparative Example 103, since there is too much Zr, the intermetallic compound B increases, and the number of repeated fractures and the electrical conductivity are poor.
Comparative Examples 104 to 110 and Comparative Example 201 indicate that the area ratio of the intermetallic compound in the aluminum alloy conductor is out of the scope of the present invention or is broken during the production. Here, an example is shown in which the aluminum alloy conductor defined by the present invention is not obtained depending on the production conditions of the aluminum alloy. In Comparative Example 104, the casting cooling rate was too slow, so the wire was broken during wire drawing. In Comparative Example 105, the casting cooling rate is too fast, the amount of intermetallic compound A is small, the amount of intermetallic compound B is large, and the number of repeated fractures and the electrical conductivity are poor. In Comparative Examples 106 to 108, the temperature of the intermediate annealing was too high or too low, or the time was too short. Comparative Example 109 is in an unannealed state due to insufficient softening in the final annealing step, and no intermetallic compound was observed, so that the tensile elongation at break was poor. In Comparative Example 110, since the finish annealing temperature was too high, the amount of intermetallic compound B was small, and the tensile strength, electrical conductivity, tensile elongation at break, and number of repeated fractures were poor. In Comparative Example 201, finish annealing was performed in a batch annealing furnace, but the amount of intermetallic compound B was reduced and the number of repeated fractures was poor.
On the other hand, in Examples 1-13, the aluminum alloy conductor excellent in tensile strength, electrical conductivity, tensile fracture elongation (flexibility), and the number of repeated fractures (bending fatigue resistance) was obtained.

  While this invention has been described in conjunction with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified and are contrary to the spirit and scope of the invention as set forth in the appended claims. I think it should be interpreted widely.

  This application claims priority based on Japanese Patent Application No. 2010-043489 filed in Japan on February 26, 2010, which is hereby incorporated herein by reference. Capture as part.

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

Claims (8)

An aluminum alloy conductor containing 0.4 to 0.9 mass% of Fe, the balance being Al and inevitable impurities,
Two types of intermetallic compounds A and B exist in the conductor,
The particle size of the intermetallic compound A is in the range of 0.1 μm to 2 μm,
The particle size of the intermetallic compound B is in the range of 0.03 μm or more and less than 0.1 μm,
The area ratio a of the intermetallic compound A and the area ratio b of the intermetallic compound B in an arbitrary range in the conductor satisfy 1% ≦ a ≦ 6% and 1% ≦ b ≦ 5%, respectively. Aluminum alloy conductor characterized by An aluminum alloy conductor containing 0.4 to 0.9 mass% of Fe and 0.01 to 0.4 mass% of Zr, the balance being Al and inevitable impurities,
Two types of intermetallic compounds A and B exist in the conductor,
The particle size of the intermetallic compound A is in the range of 0.1 μm to 2 μm,
The particle size of the intermetallic compound B is in the range of 0.03 μm or more and less than 0.1 μm,
The area ratio a of the intermetallic compound A and the area ratio b of the intermetallic compound B in an arbitrary range in the conductor satisfy 1% ≦ a ≦ 6% and 1% ≦ b ≦ 7.5%, respectively. An aluminum alloy conductor characterized by:   The crystal grain size in a vertical cross section in the wire drawing direction is set to 1 to 15 μm by performing continuous energization heat treatment including rapid heating and rapid cooling processes at the end of the manufacturing process of the conductor. The aluminum alloy conductor described in 1.   The aluminum alloy conductor according to any one of claims 1 to 3, which has a tensile strength of 80 MPa or more and an electrical conductivity of 60% IACS or more.   The aluminum alloy conductor according to any one of claims 1 to 4, having an elongation at break of 10% or more.   The aluminum alloy conductor according to any one of claims 1 to 5, which has a recrystallized structure.   The aluminum alloy conductor according to any one of claims 1 to 6, wherein the conductor is used as a battery cable, a harness, or a wire for a motor in a moving body.   The aluminum alloy conductor according to claim 1, wherein the conductor is used in a vehicle, a train, or an aircraft.

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