JP2018141209A - Method for manufacturing aluminum alloy wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an aluminum alloy wire that can improve wire drawability and flex resistance while increasing production quantity manufactured in one process.SOLUTION: A method for manufacturing an aluminum alloy wire comprises: a casting step of casting molten metal of an aluminum alloy containing 2.0 wt% to 3.5 wt% of Fe, 0.1 wt% to 0.5 wt% of Si, and the balance Al with inevitable impurities to form a casting material having a diameter of 50 mn or more; a first heat treatment step of subjecting the casting material produced in the casting step to intermediate heat treatment; a first wire drawing step of subjecting the casting material produced in the first heat treatment step to wire drawing to form a wire rod; a second heat treatment step of subjecting the wire rod produced in the first wire drawing step to intermediate heat treatment; a second wire drawing step of subjecting the wire rod produced in the second heat treatment step to wire drawing processing; and a softening step of subjecting the wire rod produced in the second wire drawing step to softening heat treatment.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing an aluminum alloy wire.

  In recent years, wires using aluminum have attracted attention as substitutes for copper wires and copper alloy wires as magnet wires and wire materials for harnesses. This is because an increase in the amount of copper wire or copper alloy wire is used to predict resource depletion or price increases, and alternatives are desired. Moreover, since the wire using aluminum is lighter than a copper wire or a copper alloy wire, for example, when used in an electronic device of an automobile, fuel efficiency can be improved.

  On the other hand, wire made of pure aluminum has lower tensile strength than copper wire or copper alloy wire, and when the wire is covered with an insulating material or when a coil of magnet wire is formed (winding), the wire is not There was a risk of breaking under tensile force. In addition, pure aluminum wire is inferior in bending resistance compared to copper wire and copper alloy wire, so it can be used in environments with bending, such as when forming coils, and in environments that receive vibration such as automotive electronic equipment. Limited.

  Then, the manufacturing method of the aluminum alloy wire which improved the tensile strength rather than the pure aluminum wire is known (for example, refer patent documents 1-3).

  In the manufacturing method of Patent Document 1, a cast material having a diameter of 9.5 mm is obtained by casting and rolling a molten aluminum alloy composed of 0.005 wt% or more and 2.2 wt% or less of Fe and the balance being Al and impurities. A casting process for forming, a wire drawing process for forming a wire having a wire diameter of 0.3 mm by drawing the cast material, and a softening process for applying a softening heat treatment to the wire.

  The manufacturing method of Patent Document 2 is casting a molten aluminum alloy consisting of Fe in an amount of 2.0 wt% to 3.5 wt%, Si in excess of 0 wt% to 1.0 wt%, and the balance being Al and inevitable impurities. A casting process for forming a casting material having a diameter of 15 mm, a wire drawing process for drawing a casting material to form a wire material having a wire diameter of 0.5 mm, and a softening treatment for softening the wire material And a process.

  The manufacturing method of Patent Document 3 is a molten aluminum alloy in which Fe is 1.0 wt% or more and 2.5 wt% or less, Si is 0.05 wt% or more and 0.25 wt% or less, and the balance is Al and inevitable impurities. Casting and forging to form a cast material having a diameter of 10 mm, drawing process for drawing a cast material to form a wire having a wire diameter of 0.5 mm, and softening with respect to the wire And a softening step for performing heat treatment. Further, the cast material formed in the casting process is subjected to a heat treatment at 400 ° C.

JP 2015-227508 A JP 2014-224290 A Japanese Patent Laid-Open No. 2006-60963

  Aluminum alloy wires manufactured by conventional manufacturing methods have conductivity of 58% IACS (international annealed copper standard) or higher, tensile strength of 120 MPa or higher, elongation of 15% or higher, and can be used as an alternative to copper wires and copper alloy wires. It is. However, the diameter of the cast material before drawing is 15 mm or less, and the production amount of aluminum alloy wires produced in one process is small.

  On the other hand, when the diameter of the cast material formed in the casting process is increased, the conventional manufacturing method is easy to break when the wire diameter of the aluminum alloy wire is drawn to 0.2 mm, and the bending resistance is reduced. To do. In particular, in the production methods of Patent Documents 2 to 3, the number of breaks in the bending resistance test is about 12 at the maximum, and there is room for further improving the bending resistance.

  Therefore, there is a demand for a method for producing an aluminum alloy wire that can improve wire drawing workability and bending resistance while increasing the production amount produced in a single process.

  The characteristic composition of the method for producing an aluminum alloy wire is that Fe is contained in an amount of 2.0 to 3.5% by weight, Si is contained in an amount of 0.1 to 0.5% by weight, and the balance is Al and inevitable impurities A casting step of casting a molten aluminum alloy to form a cast material having a diameter of 50 mm or more, a first heat treatment step of performing an intermediate heat treatment on the cast material obtained in the casting step, and the first A first wire drawing step of forming a wire by drawing the cast material obtained in the heat treatment step; a second heat treatment step of performing an intermediate heat treatment on the wire obtained in the first wire drawing step; A second wire drawing step of drawing the wire obtained in the second heat treatment step, and a softening step of performing a softening heat treatment on the wire obtained in the second wire drawing step. In the point.

  In this method, since a cast material having a large diameter of 50 mm or more is used, it is possible to increase the production amount of an aluminum alloy wire manufactured in one process. Further, in this method, since the intermediate heat treatment is performed on the cast material, the structure of the material constituting the cast material can be homogenized.

  Furthermore, since the intermediate heat treatment is performed on the wire formed in the first wire drawing step, precipitation of a compound, phase change, and the like occur due to the movement of Fe or Si dissolved in the Al crystal grains. For example, precipitation of fine Al—Fe compound or Al—Fe—Si compound, phase change in which a metastable phase (βAl—Fe—Si), which is a phase during casting, is changed to a stable phase (αAl—Fe—Si) ( Morphological changes) occur. As a result, it is possible to improve the drawing workability and the bending resistance of the aluminum alloy wire. Finally, by performing a softening heat treatment, the distortion of the aluminum alloy wire is removed and the precipitate is uniformly dispersed to improve the conductivity and strength.

  Thus, the manufacturing method of the aluminum alloy wire which can be mass-produced and can improve wire drawing workability and bending resistance has been provided.

  In another characteristic configuration, before and after the first wire drawing step and the second wire drawing step, the cross-section reduction rate when the cast material and the wire material are drawn is set to 99.75% or less. In the point.

  As in the present method, the first heat treatment step and the second heat treatment step are set so that the cross-sectional reduction rate of the wire diameter after the wire drawing before the wire drawing is 99.75% or less. If the intermediate heat treatment is performed, precipitation or phase change of the compound due to the movement of Fe or Si dissolved in the Al crystal grain boundary occurs, so that the wire drawing workability and the bending resistance can be improved. .

  Another characteristic configuration is that in the second heat treatment step, the wire is subjected to intermediate heat treatment twice or more, and the wire diameter of the wire before the final intermediate heat treatment is 8 mm or less.

  As in this method, if the wire is subjected to intermediate heat treatment twice or more and the wire diameter of the wire before the final intermediate heat treatment is 8 mm or less, the wire drawing workability and bending resistance are further improved. Can do.

  Another characteristic configuration is that it further includes a cutting step of cutting the surface of the cast material between the casting step and the first heat treatment step.

  If the surface of the cast material is cut before the drawing process as in this method, the metal oxide is removed, so that the drawing processability of the aluminum alloy wire can be improved.

  Another characteristic configuration is that the second heat treatment step performs furnace cooling by holding the wire for 10 minutes or more in a batch process.

  As in this method, if the method of performing furnace cooling while holding the wire for 10 minutes or more as an intermediate heat treatment as an intermediate heat treatment, the fineness due to the movement of Fe or Si dissolved in the Al crystal grain boundary is adopted. Phase change (morphological change) in which a metastable phase (βAl-Fe-Si), which is a phase at the time of casting, precipitation of a pure Al-Fe compound or Al-Fe-Si compound, is changed to a stable phase (αAl-Fe-Si) The crystal grains are refined due to the effect of pinning the grain boundaries during recrystallization of the processed structure, and the wire drawing workability and bending resistance can be improved.

It is a manufacturing flowchart of an aluminum alloy wire. It is a figure which shows the manufacturing conditions in a present Example and a comparative example. It is a figure which shows the method of a flexibility test. It is a physical-property evaluation figure of the aluminum alloy wire in a present Example and a comparative example.

  Embodiments of an aluminum alloy wire manufacturing method according to the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the invention.

  Since the tensile strength of aluminum is about 0.4 to 0.6 times the tensile strength of copper, when a wire having the same tensile strength as copper is formed of aluminum, the cross-sectional area is 1.67 of the copper wire. Double to 2.5 times the aluminum wire is required. However, since the specific gravity of aluminum is 1/3 of the specific gravity of copper, the mass per unit length of an aluminum wire having a cross-sectional area 1.67 to 2.5 times that of copper wire is lighter than that of copper wire. . For example, in order to obtain the same tensile strength as copper, even if the cross-sectional area of the aluminum wire is 1.67 to 2.5 times that of the copper wire, the mass of the aluminum wire is about 1/2 to that of the copper wire. A mass of about 5/6 is sufficient.

  Moreover, the electrical conductivity of aluminum is about 0.6 times that of copper, and in order to pass the same current, the cross-sectional area of the aluminum wire needs to be 1.67 times that of the copper wire. However, since the specific gravity of aluminum is 1/3 of the specific gravity of copper, as with the tensile strength, even if the cross-sectional area of the aluminum wire is increased in order to ensure the same electrical conductivity as that of the copper wire, The mass is about 1/2 compared to copper wire. As described above, the aluminum wire can be reduced in weight, but it is required to improve the wire drawing workability and the bending resistance while maintaining the desired tensile strength and conductivity even if the wire diameter is reduced. It has been. For this purpose, the method for producing an aluminum alloy wire containing Fe or Si in this embodiment is useful. Below, a composition and manufacturing method of an aluminum alloy wire are demonstrated.

  The aluminum alloy wire in this embodiment contains Fe (iron) in an amount of 2.0 wt% to 3.5 wt%, Si (silicon) in an amount of 0.1 wt% to 0.5 wt%, with the balance being Al. (Aluminum) and inevitable impurities. Since Fe, Si, and Al are abundant as resources, an increase in material cost due to resource depletion hardly occurs, and an aluminum alloy wire can be manufactured at low cost.

[composition]
(Fe: 2.0% to 3.5% by weight)
Fe contributes to the improvement of the tensile strength of the aluminum alloy wire. That is, the tensile strength of the aluminum alloy wire increases as the Fe content increases, and the tensile strength of the aluminum alloy wire becomes 120 MPa or more by containing Fe by 2.0% by weight or more. For this reason, even when the wire is covered with an insulating material or when a coil of magnet wire is formed (winding), the wire does not break even if it receives a large tensile force.

  On the other hand, when there is too much content of Fe of an aluminum alloy wire, electrical conductivity and elongation rate will fall. For this reason, in order to obtain the electrical conductivity of 58% IACS or more and the elongation of 15% or more, the Fe content needs to be 3.5% by weight or less. Thus, the Fe content of the aluminum alloy wire needs to be 2.0 wt% or more and 3.5 wt% or less, and more preferably 2.0 wt% or more and 2.5 wt% or less.

(Si: 0.1 wt% or more and 0.5 wt% or less)
By containing 0.1 wt% or more of Si in the aluminum alloy wire, it is possible to suppress a decrease in conductivity and elongation due to the inclusion of Fe. In addition, the inclusion of Si in the aluminum alloy wire has the effect of improving wire drawing workability and bending resistance. This is because precipitation of Fe dissolved in aluminum at the grain boundary is promoted, and a fine Al—Fe compound or Al—Fe—Si compound is precipitated at the Al crystal grain boundary. As a result, the aluminum alloy wire in the present embodiment can withstand fatigue due to bending stress, and is preferably used even in an environment where bending stress acts such as a magnet wire or a wire for a wire used in an electronic device of an automobile. be able to.

  On the other hand, when the content of Si in the aluminum alloy wire is too large, the desired tensile strength cannot be obtained, and conversely, the conductivity is lowered. For this reason, in order to obtain a tensile strength of 120 MPa or more and a conductivity of 58% IACS or more, the Si content needs to be 0.5% by weight or less. Thus, the Si content of the aluminum alloy wire needs to be 0.1 wt% or more and 0.5 wt% or less, and more preferably 0.2 wt% or more and 0.3 wt% or less.

[Production method]
As shown in FIG. 1, the manufacturing method of the aluminum alloy wire in this embodiment is equipped with a casting process, a 1st heat treatment process, a 1st wire drawing process, a 2nd heat treatment process, a 2nd wire drawing process, and a softening process in order. ing. The casting process casts a molten aluminum alloy containing Fe in the range of 2.0 wt% to 3.5 wt%, Si in the range of 0.1 wt% to 0.5 wt%, the balance being Al and inevitable impurities. Thus, a cast material having a diameter of 50 mm or more is formed.

  In the first heat treatment step, an intermediate heat treatment is performed on the cast material obtained in the casting step. Moreover, you may further provide the cutting process which cuts the surface of a cast material between a casting process and a 1st heat treatment process. In the first wire drawing step, the cast material obtained in the first heat treatment step is drawn to form a wire. In the second heat treatment step, an intermediate heat treatment is performed on the wire obtained in the first wire drawing step. In the second wire drawing step, the wire obtained in the second heat treatment step is drawn. In the softening step, softening heat treatment is performed on the wire obtained in the second wire drawing step. In addition, you may provide the cutting process which cuts the surface of a wire in the middle of a 1st wire drawing process.

  Furthermore, in this embodiment, the state set so that the cross-sectional reduction rate when the cast material and the wire were drawn before and after the first wire drawing step and the second wire drawing step was 99.75% or less. Thus, the intermediate heat treatment in the first heat treatment step and the second heat treatment step is performed. As a result, it is possible to improve the wire drawing workability and the bending resistance while increasing the production amount of the aluminum alloy wire manufactured in a single process by setting the diameter of the cast material to 50 mm or more. These characteristics are due to the precipitation of fine Al—Fe compounds and Al—Fe—Si compounds due to the movement of Fe and Si dissolved in Al crystal grains, and the metastable phase (βAl— The crystal grains were refined by the phase change (morphological change) in which Fe-Si) changed to a stable phase (αAl-Fe-Si) and the effect of pinning the grain boundary during recrystallization of the processed structure. This is thought to have improved.

  An example of a method for manufacturing an aluminum alloy wire according to the present embodiment will be described with reference to FIG.

  First, Fe, Si, and Al are added so as to have the above-described composition to produce a molten aluminum alloy, and cast into an iron mold having an inner diameter of 68 mm to produce an aluminum alloy cylinder (cast material) (# 10, casting Process). Next, the metal oxide that becomes a surface defect during casting is removed by cutting to form an aluminum alloy cylinder having a diameter of 50 mm (# 11, cutting step). The cutting process may be omitted. Moreover, the diameter of the aluminum alloy cylinder in a casting process should just be 50 mm or more, and is not specifically limited.

  Next, the aluminum alloy cylinder is put into an argon gas atmosphere furnace (a batch furnace in which argon gas is flowed), and is heated from 400 ° C. to 550 ° C. at a heating rate of about 50 ° C./min, and held for 10 minutes to 5 hours. After that, a batch process in which the furnace is cooled for about 15 minutes is performed (# 12, first heat treatment step). By this first heat treatment step, the structure of the material constituting the aluminum alloy cylinder is homogenized. Moreover, it is easy to manage a heating state by the batch process which heats in the state which enclosed the aluminum alloy cylinder in the argon gas atmosphere furnace.

  Next, after swaging (drawing) the aluminum alloy cylinder cold (room temperature to about 100 ° C.) (# 13, first wire drawing process), cutting (# 14) if necessary, swaging By performing the processing (# 15, first wire drawing step), the cross-sectional area of the aluminum alloy cylinder is reduced to obtain an aluminum alloy wire (wire). Thereby, the diameter of the produced aluminum alloy wire is about 20 mm (the cross-sectional reduction rate is 84% with respect to the aluminum alloy cylinder 50 mm). The wire drawing in the first wire drawing step is not limited to swaging, but may be rolling, drawing, or the like.

  Next, the aluminum alloy wire is put into an argon gas atmosphere furnace, heated at 400 ° C. to 550 ° C. at a heating rate of about 50 ° C./min, held for 10 minutes to 5 hours, and then cooled in the furnace for about 15 minutes. Processing is performed (# 16, second heat treatment step). By this second heat treatment step, the aluminum alloy wire undergoes compound precipitation and phase change (morphological change) due to the movement of Fe and Si. Moreover, since it is a batch process which heats in the state which enclosed the aluminum alloy wire in the argon gas atmosphere furnace, it is easy to control the precipitation of a compound, a form change, and the pinning effect. As a result, it is possible to improve the drawing workability and the bending resistance of the aluminum alloy wire.

  Next, the aluminum alloy wire is swaged (drawn) at a cold temperature (about room temperature to about 100 ° C.) to reduce the cross-sectional area, and the wire diameter is about 8 mm, about 3 mm, or about 1 mm (each aluminum alloy wire). An aluminum alloy wire having a cross-sectional reduction rate of 84%, 97.75%, or 99.75% with respect to 20 mm is produced (# 17, second wire drawing step). In addition, the wire drawing process in a 2nd wire drawing process is not limited to a swaging process, A rolling process, a drawing process, etc. may be sufficient.

  Next, the intermediate heat treatment similar to # 16 is performed on the aluminum alloy wire (# 18, second heat treatment step). After this second heat treatment step, the aluminum alloy wire is drawn (drawn) at a cold temperature (about room temperature to about 100 ° C.) to reduce the cross-sectional area to a wire diameter of about 0.5 mm (aluminum An aluminum alloy wire having a cross-section reduction rate of 99.61%, 97.22%, or 75% with respect to the alloy wire of 8 mm, 3 mm, or 1 mm is prepared (# 19, second wire drawing step).

  On the other hand, after passing through the second heat treatment step # 18, the aluminum alloy wire having a wire diameter of about 8 mm is drawn (drawn) in a cold state (room temperature to about 100 ° C.), thereby reducing the cross-sectional area. An aluminum alloy wire having a wire diameter of about 3 mm or a wire diameter of about 1 mm (85.9% or 98.4% reduction in cross section with respect to an aluminum alloy wire of 8 mm) may be produced (# 20, second elongation). Line process). In this case, the obtained aluminum alloy wire is again subjected to an intermediate heat treatment similar to # 16 (# 21, second heat treatment step), and drawn (drawn) to reduce the cross-sectional area. Then, an aluminum alloy wire having a wire diameter of about 0.5 mm (cross-sectional reduction rate of 97.22% or 75% with respect to aluminum alloy wire 3 mm or 1 mm) is produced (# 22, second wire drawing step). In addition, the wire drawing process in a 2nd wire drawing process is not limited to a drawing process, A rolling process, a swaging process, etc. may be sufficient.

  An aluminum alloy wire having a wire diameter of about 0.5 mm obtained in # 19 or # 22 is put into an argon gas atmosphere furnace and heated to 250 ° C. to 400 ° C. at a temperature rising rate of about 50 ° C./min for 10 minutes or more. After holding for 5 hours or less, batch processing is performed in which the furnace is cooled for about 15 minutes (# 23, softening step). As a result, the distortion of the aluminum alloy wire can be removed and the precipitates can be uniformly dispersed to improve the conductivity and strength.

  A plurality of aluminum alloy wires were produced and their physical properties were evaluated.

1. Manufacturing method (this example)
In Examples 1 to 9, aluminum alloy wires having compositions of Fe, Si, and Al as shown in FIG. 2 were produced. As shown in FIG. 1, the manufacturing method of the aluminum alloy wire in the present embodiment is in order of a casting process, a cutting process, a first heat treatment process, a first wire drawing process (including intermediate cutting), a second heat treatment process, and a second. It has a wire drawing process and a softening process.

  In the casting process, Fe, Si, and Al were added so as to have the composition shown in FIG. 2 to produce a molten aluminum alloy, and cast into an iron mold having an inner diameter of 68 mm to produce an aluminum alloy column (cast material). Next, in the cutting process, the surface defects of the aluminum alloy cylinder were removed by cutting to form an aluminum alloy cylinder having a diameter of 50 mm.

  Next, in the first heat treatment step, the aluminum alloy cylinder is put into an argon gas atmosphere furnace and maintained at a temperature raising rate of about 50 ° C./min for 2 hours while being heated to the temperature of the intermediate heat treatment shown in FIG. And then cooled in the furnace. Next, in the first wire drawing step, the aluminum alloy cylinder was subjected to cold swaging, cutting and swaging in this order to produce an aluminum alloy wire having a wire diameter of 20 mm.

  Next, in the second heat treatment step, the aluminum alloy wire is put into an argon gas atmosphere furnace and kept at a temperature rising rate of about 50 ° C./min to the intermediate heat treatment temperature of 450 ° C. to 500 ° C. shown in FIG. 2 for 2 hours. And then cooled in the furnace. Next, in the second wire drawing step, the aluminum alloy wire was subjected to a swaging process in a cold state to produce an aluminum alloy wire having a wire diameter of 8 mm, 3 mm, or 1 mm.

  Next, an intermediate heat treatment similar to the second heat treatment step described above was performed on an aluminum alloy wire having a wire diameter of 8 mm, 3 mm, or 1 mm. In Examples 4, 5, 7, and 9, aluminum alloy wires with a wire diameter of 8 mm, 3 mm, or 1 mm were cold drawn to produce aluminum alloy wires with a wire diameter of 0.5 mm. That is, in Examples 4, 5, 7, and 9, the intermediate heat treatment of the first heat treatment step was performed once, the intermediate heat treatment of the second heat treatment step was performed twice, and the total number of intermediate heat treatments was three times. (See FIG. 2). In Examples 4, 5, 7, and 9, the wire diameters before the final intermediate heat treatment were all 8 mm or less as shown in FIG. 2, and the cross-sectional reduction rate after drawing was 99.75% or less. Was set to be.

  On the other hand, in Examples 1, 2, 3, 6, and 8, an aluminum alloy wire having a wire diameter of 8 mm is cold drawn to produce an aluminum alloy wire having a wire diameter of 3 mm, and the above-described second heat treatment is performed. The intermediate heat treatment similar to the process was performed. And the aluminum alloy wire with a wire diameter of 3 mm was cold-drawn, and the aluminum alloy wire with a wire diameter of 0.5 mm was produced. That is, in Examples 1, 2, 3, 6, and 8, the intermediate heat treatment in the first heat treatment step is performed once, the intermediate heat treatment in the second heat treatment step is performed three times, and the total number of intermediate heat treatments is four times. (See FIG. 2). In Examples 4, 5, 7, and 9, the wire diameters before the final intermediate heat treatment were all 8 mm or less as shown in FIG. 2, and the cross-sectional reduction rate after drawing was 99.75% or less. Was set to be.

  Finally, the prepared aluminum alloy wire having a wire diameter of 0.5 mm was put into an argon gas atmosphere furnace in which argon gas was circulated and heated to 300 ° C. to 400 ° C. at a temperature rising rate of about 50 ° C./min. After holding the time, the furnace was cooled for about 15 minutes.

(Comparative example)
Comparative Examples C1 to C4 produced aluminum alloy wires having compositions as shown in FIG. That is, Comparative Examples C1 and C2 contain Fe in the range of 2.0 wt% to 3.5 wt%, Si in the range of 0.1 wt% to 0.5 wt%, with the balance being the same as in this example. It is an aluminum alloy wire made of Al and inevitable impurities. On the other hand, Comparative Examples C3 and C4 contain elements such as Zr (zirconium), Ti (titanium), and B (boron) in addition to Fe, Si, and Al.

  As a manufacturing method of the aluminum alloy wire in the comparative example, Comparative Example C1 includes only the casting process, the cutting process, the first heat treatment process, the first wire drawing process, and the softening process shown in FIG. The intermediate heat treatment was performed once. Comparative Examples C2 to C4 include the casting process, the cutting process, the first heat treatment process, the first wire drawing process, the second heat treatment process, the second wire drawing process, and the softening process shown in FIG. For C2, the same intermediate heat treatment as in the above-described embodiment was performed twice, and in Comparative Examples C3 to C4, the same intermediate heat treatment as in the above-described embodiment was performed three times.

2. Evaluation of produced aluminum alloy wire The electrical conductivity (% IACS), tensile strength (MPa), and elongation (%) of each produced aluminum alloy wire were measured. Each aluminum alloy wire is not coated with an insulating material and has a wire diameter of 0.5 mm. The conductivity was measured by the 4-terminal method. Tensile strength and elongation were measured according to JISZ2241. Moreover, the bending resistance of each produced aluminum alloy wire was evaluated. Further, each produced aluminum alloy wire was further drawn to evaluate whether or not an aluminum alloy wire having a wire diameter of 0.2 mm could be formed.

  In evaluating the bending resistance, a bending test was performed. FIG. 3 is a diagram showing a method of a flexibility test. As shown in FIG. 3A, the aluminum alloy wire 1 was sandwiched between a pair of mandrels 2 (diameter 2.0 mm). A space of 1 mm was provided between the pair of mandrels 2. One end side of the aluminum alloy wire 1 was inserted through a through hole for preventing vibration formed in the holding plate 5. One end of the aluminum alloy wire 1 was pulled downward by a 200 g weight 3. The other end of the aluminum alloy wire 1 was held by a chuck 4. By moving the chuck 4, it was bent 90 ° rightward on the paper surface from the state shown in FIG. Subsequently, the aluminum alloy wire 1 was bent 90 ° to the left on the paper surface from the state (b) to the state (c). (A) → (b) → (c) → (a) was counted once and this was repeated. This number of repetitions is referred to as the number of bendings. The bending rate was 30 times / minute, and the flexibility test was performed without energization.

  In FIG. 4, the measurement result and evaluation result about each aluminum alloy wire are shown. In FIG. 4, the numerical value shown in the column of the number of bending breaks is an average value when a plurality of bendability tests are performed on each aluminum alloy wire. Moreover, in the column of φ0.2 mm processing, a sample that can be produced by drawing an aluminum alloy wire having a wire diameter of φ0.2 mm is indicated as “O” (passed), and a sample that cannot be produced is indicated as “x” (failed). Indicated. In the evaluation column, the electrical conductivity is 58% IACS or more, the tensile strength is 120 MPa or more, the elongation is 15% or more, the number of breaks is 38 times or more, and the linear φ0.2 mm Samples that were able to be drawn were marked with ◯ (accepted), and samples that could not be achieved with any one of the above (ie samples other than ◯) were marked with x (failed).

  Examples 1-9 and Comparative Examples C1-C4 all have a conductivity of 58% IACS or higher, a tensile strength of 120 MPa or higher, and an elongation of 15% or higher.

  In all of the examples, the number of bending breaks was 38 times or more, excellent bending resistance, and good wire drawing workability. On the other hand, in Comparative Examples C1 to C4, the number of times of fracture bending is smaller than that of the present example, and in particular, Comparative Example C1 where the number of intermediate heat treatments is small, and Comparative Example C3 in which the aluminum alloy wire contains Zr, The number of times was inferior. Moreover, the magnet wire was produced by apply | coating insulating polyamide to the aluminum alloy wire which concerns on this Example 1 and 5, and forming insulating coating. And the produced magnet wire was wound around the core of the vehicle-mounted motor. At this time, no disconnection occurred.

  From these, in an aluminum alloy wire containing Fe of 2.0 wt% to 3.5 wt%, Si of 0.1 wt% to 0.5 wt%, and the balance being Al and inevitable impurities, 50 mm or more It can be seen that the wire drawing workability and the bending resistance are improved by subjecting the cast material having a wire diameter of at least 3 times to the intermediate heat treatment and wire drawing.

[Other Embodiments]
In the above-described embodiment, the intermediate heat treatment in the first heat treatment step and the second heat treatment step is performed by heating an aluminum alloy cylinder or an aluminum alloy wire in an atmosphere furnace and cooling the furnace. Instead, it may be heated in an air furnace and cooled in the atmosphere, or may be heated in an atmosphere furnace and cooled in the atmosphere, and is not particularly limited.

  The present invention can be used in a method for producing an aluminum alloy wire.

1 Aluminum alloy wire

Claims (5)

50 mm or more by casting a molten aluminum alloy containing Fe in an amount of 2.0 wt% to 3.5 wt%, Si in an amount of 0.1 wt% to 0.5 wt% with the balance being Al and inevitable impurities A casting process for forming a cast material having a diameter of
A first heat treatment step of performing an intermediate heat treatment on the cast material obtained in the casting step;
A first wire drawing step of forming a wire by drawing the cast material obtained in the first heat treatment step;
A second heat treatment step of performing an intermediate heat treatment on the wire obtained in the first wire drawing step;
A second wire drawing step of drawing the wire obtained in the second heat treatment step;
And a softening step in which a softening heat treatment is performed on the wire obtained in the second wire drawing step.   The cross-sectional reduction rate when the cast material and the wire are drawn before and after the first wire drawing step and the second wire drawing step is set to 99.75% or less. Manufacturing method of aluminum alloy wire.   The method for producing an aluminum alloy wire according to claim 1 or 2, wherein in the second heat treatment step, the wire is subjected to intermediate heat treatment twice or more, and the wire diameter of the wire before the last intermediate heat treatment is 8 mm or less. .   The method for producing an aluminum alloy wire according to any one of claims 1 to 3, further comprising a cutting step of cutting a surface of the cast material between the casting step and the first heat treatment step.   The said 2nd heat treatment process is a manufacturing method of the aluminum alloy wire as described in any one of Claim 1 to 4 which hold | maintains the said wire for 10 minutes or more by batch processing, and performs furnace cooling.

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