JP2013076168A - Aluminum alloy wire, aluminum alloy stranded wire, coated wire, and wire harness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: an extra fine aluminum (Al) alloy wire having high strength and high conductivity and excellent in elongation; an Al alloy stranded wire; a covered electric wire comprising the Al alloy wire; and a wire harness.SOLUTION: The extra fine aluminum alloy wire has a wire diameter of 0.5 mm or less, contains, by mass, 0.03%-1.5% Mg, 0.02%-2.0% Si, 0.1%-1.0% in total of one or more elements selected from Cu, Fe, Cr, Mn and Zr, and the remainder comprising Al and impurities, and has a conductivity of 40% IACS or more, a tensile strength of 150 MPa or more, and an elongation of 5% or more. The aluminum alloy wire comprises the Al alloy having a specific composition containing Zr, Mn and the like, and has a structure having the maximum crystal grain diameter of 50 μm or less, so that, even if it is an extra fine wire, the Al alloy wire is excellent in elongation. The Al alloy wire has a tensile strength of 150 MPa or more after being held for 1,000 hours at arbitrary temperature selected from 80 to 150°C, and the Al alloy wire is excellent in heat resistance.

Description

  The present invention relates to an aluminum alloy wire and an aluminum alloy stranded wire used for a conductor of an electric wire, a covered electric wire using the alloy wire or a stranded wire as a conductor, and a wire harness including the covered electric wire. In particular, the present invention relates to an aluminum alloy wire that is extremely thin and has excellent strength and high electrical conductivity.

  2. Description of the Related Art Conventionally, a form called a wire harness in which a plurality of electric wires having terminals are bundled is used for a wiring structure of an electric device such as a transport device such as an automobile or a control device such as an industrial robot. Copper-based materials such as copper and copper alloys, which are excellent in electrical conductivity, are mainly used as constituent materials for electric conductors for wire harnesses.

  In recent years, the performance and functionality of automobiles have been rapidly increased, and with the increase in various on-vehicle electric devices and control devices, the number of electric wires used for these devices is also increasing. On the other hand, in recent years, there has been a strong demand for weight reduction in order to improve the fuel efficiency of transportation devices such as automobiles in order to cope with the environment.

  In order to reduce the weight of electric wires, aluminum electric wires using aluminum, whose specific gravity is about 1/3 that of copper, are being studied. However, pure aluminum is inferior in impact resistance, bending characteristics, and heat resistance to copper-based materials. For this reason, for example, pure aluminum is used in places that perform opening and closing operations such as door parts, places that are subject to vibration such as around the engine, such as dynamic places where bending or vibration is applied, and high-temperature places such as around the engine that becomes hot. If an electric wire is applied, there is a risk of early disconnection. Therefore, the application of the pure aluminum electric wire is limited to a static location that is not substantially moved after installation, such as a wiring for an accessory in a vehicle, or a low-temperature location from room temperature to about 50 ° C. at most.

  On the other hand, Patent Document 1 discloses that an aluminum alloy wire having high strength and high electrical conductivity and excellent impact resistance can be obtained by performing a softening treatment after drawing, and this high strength and high toughness aluminum alloy. It discloses that a wire is used as a conductor of an in-vehicle wire harness electric wire. Since this aluminum alloy wire is excellent in impact resistance, it can also be applied to the above-mentioned dynamic locations.

Japanese Patent No. 4646998

  Further weight reduction of electric wires is desired. Therefore, it is desirable to develop an aluminum alloy wire with a sufficient elongation in order to have a very thin wire with a wire diameter of 0.5 mm or less, high strength and high conductivity, and excellent impact resistance and bending characteristics. It is. Also, it is excellent in high temperature characteristics even when used in high temperature places such as around the engine, specifically, it has high strength (excellent high temperature strength), and even in use where it is exposed to high temperatures for a long time. It is desired that high strength can be maintained (excellent heat resistance over a long period of time).

  As a high-strength aluminum alloy, a 6000 series alloy (Al-Mg-Si series alloy) is known. In general, 6000 series alloys can be strengthened by solution treatment and aging treatment. Therefore, the present inventors manufactured an ultrafine wire having a wire diameter of 0.5 mm or less with a 6000 series alloy. However, although the obtained wire was subjected to solution treatment and aging treatment, it was high strength but did not have sufficient elongation.

  Further, conventionally, an ultrafine aluminum alloy wire excellent in high temperature strength and heat resistance has not been obtained.

  Accordingly, one of the objects of the present invention is to provide an aluminum alloy wire and an aluminum alloy twisted wire that are very fine wires, have high strength and high conductivity, and are excellent in elongation. Another object of the present invention is to provide an ultrafine aluminum alloy wire excellent in high temperature strength and heat resistance, and an aluminum alloy stranded wire.

  Furthermore, another object of the present invention is to provide a coated electric wire having a conductor that is an ultrafine wire and has high strength and high electrical conductivity and excellent in elongation, and a wire harness including the coated electric wire. There is. Another object of the present invention is to provide a coated electric wire including a conductor that is extremely thin and lightweight, and has excellent high-temperature strength and heat resistance, and a wire harness including the coated electric wire. .

  When the present inventors examined an ultrafine wire made of an Al—Mg—Si alloy, very coarse crystal grains of over 100 μm and about 300 μm were present. Since the wire diameter of this ultrafine wire is 0.5 mm or less, the ratio of the above-mentioned coarse particles to the wire diameter of the wire is more than 10%. It is considered that such coarse grains became the starting point of breakage and the elongation was reduced. Therefore, it can be said that the ultrafine wire is preferably composed of a structure in which coarse grains that are the starting point of breakage are reduced, and preferably substantially free of coarse grains.

  In order to reduce coarse crystals, it is conceivable to add Ti or B, which is effective for refinement of the crystal structure during casting. However, sufficient elongation was not obtained with the addition of Ti and B, as shown in the test examples described later, for the ultrafine wires as described above. Therefore, the present inventors, based on the Al-Mg-Si based alloy, further produced an ultrafine wire from an aluminum alloy to which various elements were added, and as a result, containing a specific element in a specific range, It has been found that an aluminum alloy wire having a structure with a small maximum crystal grain size and excellent elongation can be obtained. Moreover, the knowledge that the aluminum alloy wire which is excellent also in high temperature intensity | strength and heat resistance is obtained by containing a specific element in a specific range was acquired. The present invention is based on the above findings.

  The aluminum alloy wire of the present invention (hereinafter referred to as an Al alloy wire) is used for a conductor and is a very fine wire having a wire diameter of 0.5 mm or less. This Al alloy wire has a mass% of Mg of 0.03% to 1.5%, Si of 0.02% to 2.0%, and at least one element selected from Cu, Fe, Cr, Mn, and Zr in a total of 0.1%. More than 1.0% is contained, and the balance is made of an Al alloy composed of Al and impurities. The Al alloy wire has a conductivity of 40% IACS or more, a tensile strength of 150 MPa or more, an elongation of 5% or more, and a maximum crystal grain size of 50 μm or less.

  The Al alloy wire of the present invention has high strength because it is made of an Al—Mg—Si based alloy, and has high conductivity because the additive element is in a specific range. The Al alloy wire of the present invention contains a specific element such as Zr or Mn in a specific range, and thus has a structure with a small maximum crystal grain size, that is, a fine structure as described above, and is excellent in elongation. As described above, the Al alloy wire of the present invention is an extra fine wire having a specific microstructure, has high strength and high conductivity, and has sufficient elongation. Therefore, impact resistance and bending characteristics are required. It can utilize suitably for the conductor raw material of the electric wire obtained. In addition, the Al alloy wire of the present invention has high strength even at high temperatures as shown in the test examples described later, and can maintain high strength even after being held at high temperatures for a long time, and is excellent in high temperature strength and heat resistance. For this reason, it can be suitably used for a conductor material of an electric wire arranged at a high temperature location.

  As one form of the Al alloy wire of the present invention, a form containing 0.01% by mass or more of Zr can be mentioned.

  As a result of investigation by the present inventors, it was found that Zr has a large effect of improving elongation even in a very small amount. Therefore, the said form has higher elongation. Moreover, Zr is effective in improving the high temperature characteristics even in a very small amount, and the above form is excellent in high temperature strength and heat resistance.

  One form of the Al alloy wire of the present invention includes a form containing 0.01% by mass or more of Mn.

  As a result of investigation by the present inventors, it was found that Mn has a large effect of improving elongation even in a very small amount. Therefore, the said form has higher elongation. Mn is effective in improving the high temperature characteristics even in a very small amount, and the above form is excellent in high temperature strength and heat resistance.

  As one form of the Al alloy wire of the present invention, there is a form in which the tensile strength after holding for 1,000 hours at an arbitrary temperature selected from a temperature range of 80 ° C. or higher and 150 ° C. or lower is 150 MPa or more.

  Even if it is the use environment exposed to high temperature over a long period of time, the said form can maintain high intensity | strength and is excellent in heat resistance, Therefore It can utilize suitably for the conductor material of the electric wire arrange | positioned at a high temperature location.

  As one form of the Al alloy wire of the present invention, a form in which the tensile strength at an arbitrary temperature selected from a temperature range of 80 ° C. or more and 150 ° C. or less is 150 MPa or more can be mentioned.

  Since the said form has high intensity | strength also at high temperature, it can utilize suitably for the conductor raw material of the electric wire arrange | positioned in the location which can become high temperature.

  As one form of the Al alloy wire of the present invention, there is a form containing at least one element of Ti of 0.08% (800 ppm) or less and B of 0.016% (160 ppm) or less by mass ratio.

  Ti and B are elements that have a miniaturization effect. Therefore, the above-mentioned form containing Ti and B in addition to elements such as Zr and Mn has a high refining effect and higher elongation.

  The Al alloy wire of the present invention can be used as a single wire, but can be a strand wire. For example, as the aluminum alloy stranded wire of the present invention, one obtained by twisting a plurality of the above-described Al alloy wires of the present invention can be mentioned.

  The Al alloy stranded wire of the present invention substantially maintains the structure (structure with a small maximum grain size) and properties (tensile strength, conductivity, elongation, high temperature characteristics) of the Al alloy wire of the present invention constituting the strand. It has high strength and high electrical conductivity, and is excellent in elongation, high temperature strength, and heat resistance. In addition, by twisting together a plurality of Al alloy wires of the present invention, mechanical properties such as impact resistance and bending properties as a whole stranded wire can be improved as compared with the case of a single wire.

  The above-described Al alloy wire of the present invention and the Al alloy twisted wire of the present invention can be suitably used for conductors of electric wires. For example, as the coated electric wire of the present invention, the Al alloy wire of the present invention, an aluminum alloy stranded wire obtained by twisting a plurality of the Al alloy wires of the present invention (the Al alloy stranded wire of the present invention), or a compressed wire material obtained by compression molding this stranded wire Any of the above may be used as a conductor and an insulating coating layer may be provided on the outer periphery thereof.

  As described above, the present invention has high strength and high electrical conductivity as described above, the present invention Al alloy wire and the present invention Al alloy stranded wire, by providing the conductor with a compressed wire formed from this stranded wire, It has high strength and high electrical conductivity, is excellent in elongation, and has excellent impact resistance and bending properties. Moreover, since the Al alloy wire of the present invention is excellent in high temperature strength and heat resistance as described above, the above form is also excellent in high temperature strength and heat resistance.

  The said covered electric wire of this invention can be utilized suitably for the electric wire of a wire harness. For example, as the wire harness of the present invention, one comprising the above-described coated electric wire of the present invention and a terminal portion attached to the end of the electric wire can be mentioned.

  The above-mentioned form is provided with the coated wire of the present invention having high strength, high electrical conductivity, and high toughness as described above, so that it has high strength, high electrical conductivity, excellent elongation, and excellent impact resistance and bending. Has characteristics. Moreover, the said form is excellent also in high temperature strength and heat resistance.

  The Al alloy wire of the present invention, the twisted Al alloy wire of the present invention, the covered electric wire of the present invention, and the wire harness of the present invention have high strength and high electrical conductivity, and are excellent in elongation.

(A) is a photomicrograph of sample No.1, (B) is a photomicrograph of sample No.11, (C) is a photomicrograph of sample No.16, (D) is a microscope of sample No.102 It is a photograph.

Hereinafter, the present invention will be described in more detail. In addition, content of an element shows the mass%.
[Al alloy wire]
"composition"
The Al alloy constituting the Al alloy wire of the present invention is an Al—Mg—Si based alloy containing Mg: 0.03% to 1.5% and Si: 0.02% to 2.0% as essential elements, and is an element for crystal refinement. As an element, at least one element selected from Cu, Fe, Cr, Mn and Zr is contained. Since Mg and Si are present in a solid solution or precipitated in Al, the Al alloy wire of the present invention is excellent in strength. The higher the content of Mg and Si, the higher the strength of the Al alloy wire. However, since the toughness such as conductivity and elongation decreases, wire breakage is likely to occur even during wire drawing, so Mg: 1.5% or less, Si : 2.0% or less.

  Mg is an element having a high strength improvement effect. In particular, when Mg is contained in a specific range together with Si, the strength can be effectively improved by age hardening. The Mg and Si contents are preferably Mg: 0.2% to 1.5%, Si: 0.1% to 1.5%, more preferably Mg: 0.3% to 0.9%, and Si: 0.3% to 0.8%.

  By containing at least 0.1% of one or more elements selected from Cu, Fe, Cr, Mn and Zr in total, the maximum crystal grain size becomes a structure of 50 μm or less, and an ultrafine wire excellent in elongation can be obtained. As the total content of the above elements increases, the crystal grains tend to become finer and the effect of improving the elongation tends to be larger. However, if the amount is too large, the conductivity is lowered. Therefore, the total content of the above elements is 1.0% or less.

  Among Cu, Fe, Cr, Mn, and Zr, especially Zr and Mn have a large effect of miniaturization and an effect of improving the elongation, and the elongation can be improved even with a small amount of 0.01%. When containing Zr and Mn, the crystal structure of the material (continuous cast rolled material) obtained by continuous casting and rolling can be made sufficiently fine as described later, and the final wire diameter is obtained after continuous casting and rolling. Even if a thermal history is received by intermediate heat treatment, solution treatment, aging treatment, or the like in the manufacturing process up to this point, the crystal grains are difficult to grow and the crystal grains are easily maintained in a fine state. As a result, it is easy to obtain an ultrafine wire composed of a structure having a small maximum crystal grain size. As the amount of Zr or Mn increases, the effect of improving the elongation due to miniaturization is greater and the strength can be improved. In addition, when containing Zr and Mn, as shown in the test examples described later, it has high strength even at a high temperature of 80 ° C. or higher, and can maintain high strength even after being held at a high temperature of 80 ° C. or higher for a long time. And gained knowledge. That is, not only the heat history at the time of manufacture but also the heat history at the time of use was found to be high strength. Therefore, for applications where high temperature characteristics such as high temperature strength and heat resistance are desired in addition to high strength, high conductivity, and high toughness, a form containing Zr or Mn is preferable. In the case of containing Zr, in particular, if the content is 0.02% or more and 0.40% or less, it is possible to suppress problems such as a decrease in conductivity due to an increase in the content of Zr and cracking during casting, which is more preferable. . When containing Mn, especially when the content is 0.05% or more and 0.40% or less, problems such as a decrease in conductivity due to an increase in the Mn content, disconnection during wire drawing, and generation of slag during melting are suppressed. This is more preferable.

  Cu, Fe, and Cr all tend to have a greater effect of improving elongation due to miniaturization as the content increases, and the content per element is preferably 0.05% or more. Cu, Fe and Cr are also effective in improving the strength. When the content of each of the above elements is Cu: 0.05% or more and 0.40% or less, Fe: 0.1% or more and 0.6% or less, and Cr: 0.05% or more and 0.40% or less, the conductivity is increased by increasing the content of these elements. It is more preferable because problems such as a drop, disconnection at the time of wire drawing, and generation of slag at the time of melting can be suppressed. Moreover, when it contains Fe in the said range, it is excellent in high temperature strength and heat resistance.

  It may contain only one element of Cu, Fe, Cr, Mn, and Zr. However, when multiple elements are contained, in addition to the refinement effect, the strength can be improved as described above. Can be planned. In particular, when one of Cu, Fe and Cr (preferably Fe) and at least one of Mn and Zr are contained, the high temperature strength and heat resistance are excellent.

  In addition, since Ti and B have an effect of making the crystal structure of the Al alloy at the time of casting fine, the Al alloy preferably contains at least one of Ti and B. In addition to containing elements having the effect of miniaturization such as Zr and Mn, and also containing Ti and B, the crystal grains of the material obtained after casting (preferably continuous cast material or continuous cast rolled material) It is fine, and it is easier to maintain a fine state of crystal grains in the manufacturing process after casting (easier to suppress the growth of crystal grains). Therefore, if the composition also contains Ti and B, it is possible to obtain an ultrafine wire having a crystal structure with a small maximum crystal grain size in the final wire diameter. Although the content of B alone may be sufficient, the effect of miniaturization is more easily obtained when Ti is contained alone, and the effect of refinement is further improved when both Ti and B are contained. However, too much Ti or B leads to a decrease in electrical conductivity, so Ti: 0.08% (800 ppm (mass ratio; the same applies hereinafter)) or less, B: 0.016% (160 ppm) or less is preferable, and the effect of miniaturization To sufficiently obtain Ti, it is preferable that Ti: 0.005% (50 ppm) or more and B: 0.0005% (5 ppm) or more.

《Organization》
The Al alloy having the above specific composition is characterized in that the maximum crystal grain size is 50 μm or less. It is considered that the smaller the maximum crystal grain size, the finer the structure of the whole alloy becomes, and it becomes difficult for coarse grains to be the starting point of fracture to exist, and the elongation is excellent. In addition, the Al alloy having the above specific composition is easy to maintain a fine state of crystal grains even when exposed to a high temperature for a long time, and it is difficult for coarse grains to be the starting point of fracture, that is, A structure having a maximum crystal grain size of 50 μm or less can be maintained, and the heat resistance is excellent. Therefore, although the lower limit of the maximum crystal grain size is not particularly set, it is preferable that the ratio of the maximum crystal grain size to the wire diameter satisfies less than 10%. Depending on the composition and production conditions, the maximum crystal grain size may be 40 μm or less, and further 30 μm or less. On the other hand, the Al alloy having the above specific composition has a large crystal grain size within a range satisfying the maximum crystal grain size of 50 μm or less, thereby suppressing grain boundary sliding, which is dominant in deformation at high temperature, and high temperature strength. Excellent. For example, when the structure has a maximum crystal grain size of about 25 μm to 40 μm, it tends to be excellent in high temperature strength and heat resistance. A method for measuring the maximum crystal grain size will be described later.

《Room temperature characteristics》
The Al alloy wire of the present invention made of an Al alloy having the above specific composition and structure has high strength and high electrical conductivity. Tensile strength (room temperature): 150 MPa or more, electrical conductivity (room temperature): 40% IACS or more Fulfill. The tensile strength and the electrical conductivity can be changed depending on the kind and content of the additive element and the manufacturing conditions (the degree of wire drawing, the temperature of heat treatment (for example, aging treatment), etc.). For example, if the amount of additive elements is increased or the degree of wire drawing is increased (thinning the wire diameter), the tensile strength tends to increase and the conductivity tends to decrease. In addition, when aging treatment is performed, if the aging temperature is lowered, the tensile strength (room temperature): 240MPa or more and the conductivity (room temperature): 45% IACS or more is a high strength form, and the aging temperature is increased. Further, it is possible to obtain a form having high conductivity satisfying tensile strength (room temperature): 200 MPa or more and conductivity (room temperature): 50% IACS or more. Higher tensile strength and electrical conductivity are preferable, but considering the balance between toughness such as elongation and strength, the upper limit of tensile strength is about 400 MPa, taking into account the limit of increase in electrical conductivity due to aging precipitation of additive elements Then, the upper limit of conductivity is about 60% IACS.

  And, the Al alloy wire of the present invention contains the above specific element: Cu, Fe, Cr, Mn, Zr in a specific range, and is made of an Al alloy having a specific structure with a maximum crystal grain size of 50 μm or less, Excellent elongation and elongation (room temperature): 5% or more. Since the higher the elongation, the better the impact resistance and the bending properties, there is no particular upper limit. As will be described later, when the aging treatment is not performed and only the solution treatment is performed, the elongation is high and can be 10% or more, and when the aging treatment is performed, the elongation tends to decrease, but Cu, Fe, Cr, By containing Mn and Zr in a specific range, 5% or more can be satisfied.

<< High temperature characteristics >>
Examples of the Al alloy wire of the present invention made of an Al alloy having the above specific composition and structure include not only excellent mechanical properties at room temperature but also excellent strength at high temperatures. Specifically, the tensile strength (hereinafter, 80 ° C., 85 ° C., 100 ° C., 120 ° C., 125 ° C., 150 ° C., etc.) selected from a temperature range of 80 ° C. or higher and 150 ° C. or lower. A form that satisfies a high temperature strength of 150 MPa or more. Depending on the composition, the high-temperature strength is 160 MPa or more, further 180 MPa or more, 190 MPa or more. Typically, in the above temperature range, the higher the temperature strength is, the higher the temperature strength is, and the higher the temperature strength is, the closer the temperature temperature is to 150 ° C, the lower the high temperature strength. For example, a form where the tensile strength at 80 ° C satisfies 220 MPa or more, a form where the tensile strength at 100 ° C satisfies 215 MPa or more, a form where the tensile strength at 120 ° C satisfies 210 MPa or more, and a tensile strength at 150 ° C of 195 MPa or more The form which satisfy | fills is mentioned. It is expected that this form can be suitably used for applications in which the use temperature can be any temperature selected from 80 ° C to 150 ° C. Examples of the form having such an excellent high-temperature strength include forms composed of an Al alloy containing 0.01% or more of at least one of Mn and Zr and an Al alloy containing 0.1% or more of Fe.

  Examples of the Al alloy wire of the present invention comprising the Al alloy having the above specific composition and structure include not only excellent mechanical properties at room temperature but also excellent strength after being held at a high temperature for a long time. Specifically, after holding at an arbitrary temperature selected from a temperature range of 80 ° C. or higher and 150 ° C. or lower (for example, 80 ° C., 85 ° C., 100 ° C., 120 ° C., 125 ° C., 150 ° C., etc.) for 1,000 hours. Examples include a form in which the tensile strength (hereinafter referred to as strength after holding at high temperature) satisfies 150 MPa or more. Depending on the composition, the strength after holding at high temperature is 180 MPa or more, further 190 MPa or more, particularly 200 MPa or more, more preferably 220 MPa or more, 240 MPa or more. Further, depending on the composition, there is a form in which the strength after holding at high temperature is equal to or higher than the tensile strength at room temperature. Typically, the strength after holding at high temperature is higher as it is closer to 80 ° C in the above temperature range, and the strength after holding at high temperature tends to be lower as it is closer to 150 ° C. High strength after holding. For example, a form in which the tensile strength after holding at 80 ° C. for 1,000 hours satisfies 250 MPa or more, a form in which the tensile strength after holding at 100 ° C. for 1,000 hours satisfies 245 MPa or more, and a tensile after holding at 120 ° C. for 1,000 hours Examples include a form satisfying a strength of 240 MPa or higher, and a form satisfying a tensile strength of 200 MPa or higher after holding at 150 ° C. for 1,000 hours. It is expected that this form can be suitably used for applications that can be exposed to an arbitrary temperature selected from 80 ° C. to 150 ° C. for a long time. In addition, an improvement in strength may be expected during use. Examples of such a form excellent in strength after being held at high temperature include an Al alloy containing 0.01% or more of at least one of Mn and Zr, and an Al alloy containing 0.1% or more of Fe.

"Wire diameter"
The Al alloy wire of the present invention is an extra fine wire having a wire diameter of 0.5 mm or less. The wire diameter can be changed by appropriately adjusting the degree of processing (cross-sectional reduction rate) during wire drawing. For example, when used as a conductor for an electric wire of an in-vehicle wire harness, the wire diameter is 0.1 mm or more and 0.4 mm or less.

"Cross-sectional shape"
The Al alloy wire of the present invention can have various cross-sectional shapes depending on the die shape during wire drawing. A round line having a circular cross section is typical. In addition, the cross-sectional shape includes various shapes such as an elliptical shape, a polygonal shape such as a rectangle or a hexagon. In the case of an irregular shape such as the above elliptical shape or polygonal shape, the wire diameter is the maximum length in the cross section (ellipse: long diameter, rectangle or hexagon: diagonal).

[Al alloy stranded wire]
Since the Al alloy wire of the present invention is a very fine wire, a conductor having further excellent impact resistance and bending characteristics can be obtained by twisting a plurality of the Al alloy wires (present Al alloy twisted wire). The number of twists is not particularly limited. For example, 7,11,19,37,49,133 are mentioned. When the Al alloy stranded wire of the present invention is compression-molded to obtain a compressed wire, the wire diameter can be made smaller than the twisted state, and the conductor diameter can be reduced.

[Coated wire]
The Al alloy wire of the present invention, the twisted Al alloy wire of the present invention, and the above-described compressed wire can be used as conductors of electric wires as they are. As described above, it can also be used as a covered electric wire of the present invention having an insulating coating layer on the outer periphery of the conductor. Examples of the insulating material constituting the insulating coating layer include polyvinyl chloride (PVC), a non-halogen resin, and a material excellent in flame retardancy. The thickness of the insulating coating layer can be appropriately selected in consideration of desired insulation strength, and is not particularly limited.

[Wire Harness]
The said covered electric wire can be utilized suitably for the structural member of this invention wire harness. The wire harness of the present invention typically includes a plurality of electric wires including one or more of the covered electric wires of the present invention, and a terminal portion is attached to the end of each electric wire. Each said electric wire is connected to connection objects, such as an electric equipment, via the said terminal part. The wire harness of the present invention may include a wire group in which a plurality of wires are attached to one terminal portion in addition to a shape in which one terminal portion is provided for each wire. Examples of the terminal portion include various types such as a male type, a female type, a crimping type, and a welding type, and are not particularly limited. When a plurality of electric wires provided in the wire harness are bundled together by a binding tool or the like, the handling property is excellent.

[Production method]
The Al alloy wire of the present invention can typically be produced by the following production method. This manufacturing method is a manufacturing method of an aluminum alloy wire used for a conductor, and includes the following continuous casting and rolling step, wire drawing step, and solution treatment step.
Continuous casting and rolling process: In mass%, Mg is 0.03% or more and 1.5% or less, Si is 0.02% or more and 2.0% or less, and at least one element selected from Cu, Fe, Cr, Mn and Zr is 0.1% or more in total. A process of continuously casting a molten alloy of Al alloy containing 1.0% or less and the balance being Al, and then continuously rolling to form a continuously cast rolled material.
Wire drawing step: A step of drawing the continuous cast rolled material to form a wire drawn material having a wire diameter of 0.5 mm or less.
Solution forming step: A step of forming a solid solution wire by subjecting the wire drawing material to a solution treatment.
Particularly, in the solution treatment, the heating temperature is set to 450 ° C. or higher, and the cooling rate is set to 100 ° C./min or higher in the cooling step after heating.

  The manufacturing method may further include a step of applying an aging treatment to the solid solution wire to form an aging wire (aging step). In this aging treatment, the heating temperature is 100 ° C. or more and 300 ° C. or less, and the holding time is 4 hours or more.

  The manufacturing method further includes a step of homogenizing the continuous cast rolled material to form a homogeneous material (homogenizing step), and the wire drawing can be performed on the homogeneous material. . In this homogenization treatment, the heating temperature is 450 ° C. or more, the holding time is 1 hour or more, and the cooling rate is 1 ° C./min or less (slow cooling) in the cooling step after heating.

《Continuous casting and rolling process》
In order to produce an Al alloy wire having an ultrafine wire and a crystal structure having a small maximum crystal grain size, it is preferable to produce a wire having a fine crystal structure even in an upstream process of the production process. Obtained knowledge. Therefore, it is proposed to use continuous casting and rolling in the production of the Al alloy wire of the present invention. In continuous casting, since the molten metal can be rapidly solidified, a cast material having a fine crystal structure can be obtained. Although the cooling rate at the time of casting can be selected suitably, 5 degreeC / sec or more is preferable in 600 to 700 degreeC which is a solid-liquid coexistence temperature range. For example, when a continuous casting apparatus having a water-cooled copper mold, a forced water cooling mechanism, or the like is used, rapid solidification at the cooling rate as described above can be easily realized. The continuous casting includes a form using a movable mold such as a belt-and-wheel method and a form using a frame-shaped fixed mold.

  The cast material obtained by the above continuous casting is subjected to rolling subsequent to casting. In this way, the heat accumulated in the cast material can be easily used for hot rolling, energy efficiency is good, and the cast material having a fine crystal structure is immediately subjected to rolling. The rolled material (continuously cast rolled material) can also have a fine crystal structure.

  When adding Ti or B, adding just before pouring the molten metal into the mold is preferable because it suppresses local sedimentation of Ti and the like and can produce a cast material in which Ti and the like are evenly mixed. .

《Homogenization process》
As described above, solution treatment after wire drawing, and further aging treatment as appropriate, a structure with a small maximum crystal grain size, and an Al alloy wire excellent in elongation can be obtained. It was found that when the homogenization treatment was performed on the cast rolled material, an Al alloy wire excellent in elongation was easily obtained. The reason for this is that the coarse compound formed during casting (typically a compound of Mg and Si) is uniformly finely dispersed before wire drawing, so that the solution treatment step after wire drawing is concerned. This is probably because the elements can be sufficiently and uniformly dissolved. In addition, by adding elements that have a refining effect: Cu, Fe, Cr, Mn, Zr, coarsening of crystal grains can be suppressed during homogenization treatment, and in the wire drawing step described later. During intermediate heat treatment, solution treatment after wire drawing, and aging treatment, crystal growth can be prevented and a structure having a small maximum crystal grain size can be maintained.

  In the above homogenization treatment, the heating temperature is set to 450 ° C. or more and the holding time is set to 1 hour or more to uniformly and finely disperse the compound of Mg and Si generated during casting and to homogenize the composition. be able to. Preferably, the heating temperature is 500 ° C. or more and 600 ° C. or less, and the holding time is 3 hours or more and 10 hours or less. When the cooling after heating is slow cooling (cooling rate: 1 ° C./min or less), the compound of Mg and Si can be more uniformly finely dispersed. The cooling rate can be realized by, for example, a cooling method in which a heating furnace (for example, a box furnace) for performing homogenization treatment is left as it is after heating, that is, furnace cooling. Depending on the size of the heating furnace, the cooling rate can be adjusted by adjusting the temperature in the furnace by appropriately heating the atmosphere in the furnace or introducing a cooling gas or the like.

  In the present invention, a fine state can be maintained even if a homogenization heat treatment is performed by containing an element having a refining effect such as Zr or Mn in a specific range.

<Wire drawing process>
The continuous cast rolled material or homogeneous material is subjected to (cold) wire drawing. The degree of wire drawing can be appropriately selected according to a desired wire diameter. By containing elements with the effect of miniaturization such as Zr and Mn in a specific range, it is difficult to break at the time of wire drawing, and it is possible to produce a continuous long wire drawing material, which is excellent in the productivity of the wire drawing material. .

  When the intermediate heat treatment is appropriately performed during the wire drawing, the strain introduced by the processing before the intermediate heat treatment is removed, and the wire drawing workability of the wire after the intermediate heat treatment can be improved. Examples of the conditions for the intermediate heat treatment include heating temperature: 250 ° C. to 450 ° C., heating time: 0.5 hour or more. The intermediate heat treatment conditions may be the same as the solution treatment conditions described later. In the present invention, a fine state can be maintained even if an intermediate heat treatment is performed by containing an element having an effect of refining such as Zr or Mn in a specific range.

<< Solution process >>
In the case of the wire drawing material and the stranded wire having the above final wire diameter, the wire drawing material before being twisted, or the wire after twisting, and in the case of the compression wire, the wire drawing material before being twisted and the twist before compression. Solution treatment is performed on the wire or the compressed wire after compression. This solution treatment is mainly aimed at solid solution of Mg and Si. In addition, in the case of performing an aging treatment, a compound that contributes to strength: a compound of Mg and Si can be finely dispersed in crystal grains in the aging treatment in the next step by performing a solution treatment. Furthermore, by this solution treatment, the elements such as Cu, Fe, Cr, Mn, and Zr are also solid-dissolved, so that the strength can be improved.

  In the solution treatment, the heating temperature is set to 450 ° C. or higher so that Mg and Si can be sufficiently dissolved, and the solution is rapidly cooled to prevent excessive precipitation of the solid solution elements. Specifically, the cooling rate is set to 100 ° C./min or more. The faster the cooling rate, the better, and 200 ° C./min or more is more preferable. The cooling rate can be realized by forced cooling such as immersion in a liquid refrigerant such as water or liquid nitrogen or blowing air. The heating temperature is preferably 500 ° C. or more and 620 ° C. or less, more preferably 600 ° C. or less, and the holding time is 0.005 seconds or more and 5 hours or less, preferably 0.01 seconds or more and 3 hours or less. When the above-described homogenization treatment is performed, each additive element can be sufficiently dissolved even if the solution treatment time is shortened. Moreover, the continuous processing method mentioned later can be utilized suitably for such solution treatment with a short holding time.

The atmosphere during the solution treatment is typically an air atmosphere. In addition, when the atmosphere has a lower oxygen content, for example, a non-oxidizing atmosphere, generation of an oxide film on the surface of the wire to be processed due to heat during the solution treatment can be suppressed. Non-oxidizing atmospheres include, for example, a vacuum atmosphere (reduced pressure atmosphere), an inert gas atmosphere such as nitrogen (N ₂ ) and argon (Ar), a hydrogen-containing gas (for example, hydrogen (H ₂ ) only, N ₂ , Ar, A reducing gas such as a mixed gas of inert gas such as helium (He) and hydrogen (H ₂ ) or a gas containing carbon dioxide (for example, a mixed gas of carbon monoxide (CO) and carbon dioxide (CO ₂ )) The atmosphere can be mentioned.

  For the solution treatment, either a continuous treatment method or a batch treatment method described later can be used. When the continuous treatment method is used for the solution treatment, it is easy to heat-treat under uniform conditions over the entire length of the long wire, making it easy to reduce variations in characteristics and making the final wire diameter 0.5 mm or less. The heat treatment can be carried out continuously to reduce the cost, and is excellent in productivity. The continuous treatment method is a method in which a heating target (such as the above-described wire drawing material or stranded wire) is continuously supplied into a heating container and the heating target is continuously heated. For example, a direct energization method that heats the object to be heated by resistance heating (energization heating), an indirect energization method that heats the object to be heated by high-frequency electromagnetic induction (high-frequency induction heating), and other heating containers (pipe furnaces) in a heated atmosphere The furnace type which introduces a heating object inside and heats by heat conduction is mentioned. The linear velocity, energization current value, ambient temperature and the like may be adjusted so that the temperature of the heating target is 450 ° C. or higher.

  Due to the solution treatment step, the above composition is included, the wire diameter: 0.5 mm or less, the maximum crystal grain size: 50 μm or less, the conductivity (room temperature): 40% IACS or more, the tensile strength (room temperature): 150 MPa or more Elongation (room temperature): An Al alloy wire of the present invention satisfying 5% or more is obtained. The Al alloy stranded wire of the present invention is obtained by twisting the Al alloy wire, and the above-described compressed wire is obtained by compressing the stranded wire. As described above, they may be twisted or compressed before the solution treatment step.

《Aging process》
By performing an aging treatment after the solution treatment, additive elements such as Mg, Si and other Zr in the Al alloy can be precipitated, and the precipitate can be dispersed in the Al alloy. The strength of the precipitate can be improved by dispersion strengthening of the precipitates, that is, age hardening, and the conductivity can be improved by reducing the solid solution elements. Therefore, the Al alloy wire of the present invention obtained through the aging process has higher strength and higher conductivity. In addition, the Al alloy wire of the present invention contains elements that have a refining effect such as Zr and Mn, so that the crystal grains are fine even after aging, and fine precipitates are formed in the structure composed of these fine crystal grains. Tends to be a uniformly dispersed structure. By having such a fine structure, the strength can be further improved, and an Al alloy wire excellent in both strength and conductivity can be obtained. And the Al alloy wire of the present invention is excellent in elongation because it has a structure with a small maximum crystal grain size even after aging. When an aging treatment is further performed in addition to the solution treatment, the high temperature strength and the strength after holding at high temperature tend to be excellent.

  In the aging treatment, the precipitate can be sufficiently and uniformly deposited by setting the heating temperature to 100 ° C. or more and 300 ° C. or less and the holding time to 4 hours or more. When the heating temperature is lowered in the above range (180 ° C or less), the strength and elongation are high (for example, tensile strength: 240 MPa or more (300 MPa or more depending on the composition and temperature), conductivity: 45% IACS or more, elongation: When the heating temperature is increased (over 180 ° C), the conductivity is high (for example, tensile strength: 200 MPa or more, conductivity: 50% IACS or more, elongation: 5% There is a tendency to obtain a form satisfying the above. The heating temperature may be selected according to desired characteristics. The heating temperature is more preferably 140 ° C. or more and 250 ° C. or less, and the holding time is more preferably 4 hours or more and 16 hours or less. As the retention time of the aging treatment is longer, more precipitates can be precipitated, and thus the conductivity may be improved. In addition, even when the aging treatment is not performed, if the usage environment is high to some extent (especially 100 ° C or more), the strength of the aging can be improved afterwards depending on the temperature of the usage environment. is there.

  The cooling process in the aging process can utilize furnace cooling, cooling in the atmosphere, or the like, as in the above-described homogenization treatment.

  The aging treatment can use the above-mentioned continuous treatment method, but if the batch treatment method is used, the heat treatment time can be sufficiently maintained, and the precipitate can be sufficiently precipitated. The batch processing method is a heating method in which a heating target is enclosed in a heating container (atmosphere furnace, for example, a box furnace), and the atmosphere temperature may be adjusted so that the heating temperature becomes the above temperature. The atmosphere of the aging treatment may be an air atmosphere or an atmosphere having a low oxygen content as described above.

  Due to the above aging process, consisting of the above specific composition, wire diameter: 0.5 mm or less, maximum crystal grain size: 50 μm or less, conductivity (room temperature): 40% IACS or more, tensile strength (room temperature): 150 MPa or more, Elongation (room temperature): An Al alloy wire of the present invention satisfying 5% or more is obtained. The Al alloy wire may be a stranded wire or a compressed wire as described above. You may twist or compress before an aging process.

<Coating process>
Prepare the solid solution wire or aging wire (either single wire, stranded wire, or compression wire) that has been subjected to the above solution treatment or appropriate aging treatment, and an insulating coating layer made of the above insulating material on the outer periphery of these wires. By providing the process of forming, this invention covered electric wire can be manufactured.

《Terminal installation process》
The terminal harness is attached to the end portion of the obtained covered electric wire, and the wire harness of the present invention can be manufactured typically by bundling a plurality of covered electric wires with terminal portions.

[Test Example 1]
Al alloy wires were prepared and various characteristics of Al alloy wires were investigated. The Al alloy wire was prepared in the order of melting → continuous casting and rolling → homogenization → wire drawing (intermediate heat treatment) → solution treatment → aging.

  Prepare and melt pure aluminum (99.7 mass% or more Al) as a base, and add the additive elements shown in Table 1 to the resulting molten metal (molten aluminum) so that the content (mass%) shown in Table 1 is achieved. Then, an Al alloy molten metal (addition element, balance: Al) is prepared. It is desirable that the Al alloy molten metal whose components have been adjusted is appropriately subjected to a hydrogen gas removal treatment or a foreign matter removal treatment.

  Using a belt-and-wheel type continuous casting and rolling device, continuous casting and rolling is performed by continuously casting and hot rolling the prepared molten Al alloy to produce a φ9.5mm wire rod (continuous cast rolling material). did. The TiB wire was supplied to the molten Al alloy just before casting so that the sample containing Ti and B had the content (% by mass) shown in Table 1.

  The wire rod was homogenized. The homogenization treatment was performed using a box furnace, heating temperature: 530 ° C. x holding time: 5 hours, and cooling after heating was furnace cooling. The cooling rate in this cooling step is 0.89 ° C./min (1 ° C./min or less).

  The homogenized material subjected to the homogenization treatment was subjected to cold wire drawing to produce a wire drawing material having a final wire diameter of φ0.3 mm. Intermediate heat treatment (300 ° C. × 3 hours) was appropriately performed during the wire drawing.

  The obtained wire having a final wire diameter of φ0.3 mm was subjected to a solution treatment to produce a solid solution wire. The solution treatment was performed in a box furnace, and the heating temperature was set to 530 ° C. and the holding time was set to 3 hours, and the heated material was rapidly cooled. The rapid cooling is performed by immersing the material in a water tank, and the cooling rate in this cooling step is 675 ° C./min (100 ° C./min or more).

  The obtained solid solution wire (Al alloy wire) was examined for tensile strength (MPa), elongation (%), and conductivity (% IACS) at room temperature (RT, here 25 ° C.). The results are shown in Tables 2-4.

  Tensile strength (MPa) and elongation (%, elongation at break) were measured using a general-purpose tensile tester in accordance with JIS Z 2241 (metal material tensile test method, 1998). The conductivity (% IACS) was measured by the bridge method.

  The obtained solid solution wire was subjected to an aging treatment at various temperatures to produce an aging wire. The aging treatment was performed at a temperature shown in Tables 2 to 4 using a box furnace, and the holding time was 8 hours. Moreover, it cooled in air | atmosphere after heating.

  The obtained aging wire (Al alloy wire) was examined for tensile strength (MPa), elongation (%), and electrical conductivity (% IACS) at room temperature (25 ° C. in the same manner) as described above. The results are shown in Tables 2-4.

  Further, in the obtained aging wire (Al alloy wire), the sample No.1, No.11, No.16, No.102 was taken with a cross section, and this cross section was observed with an optical microscope. Fig. 1 (A) shows sample No. 1 (3000 times), Fig. 1 (B) shows sample No. 11 (1000 times), Fig. 1 (C) shows sample No. 16 (3000 times), Fig. 1 (D) is a photomicrograph of Sample No. 102 (250 times). The maximum crystal grain size was examined using the microscope images of Samples No.1, No.11, No.16 and No.102. Here, in accordance with JIS G 0551 (steel-grain size microscopic test method, 2005), a test line was drawn on the observed image, and the length of the test line in each crystal grain was divided as the crystal grain size (cutting Act). Take three fields from one cross section, draw one test line for each field, and set the largest crystal grain size among the three fields as the maximum crystal grain size. The maximum crystal grain size of other samples was examined in the same manner. The results are shown in Tables 2-4. The maximum crystal grain size was measured for a wire with an aging temperature of 160 ° C. or 180 ° C. For sample No. 15, the maximum crystal grain size was measured for the wire material after the solution treatment.

  Samples No. 1 to No. 23 containing specific elements: Cu, Fe, Cr, Mn, Zr all have a maximum crystal grain size of 50 μm or less, and FIG. 1 (A), FIG. 1 (B), FIG. As shown in 1 (C), it can be seen that the crystals are very fine and have little variation. For example, the sample No. 1 shown in FIG. 1 (A) is each crystal grain: 2 μm to 20 μm, the maximum crystal grain size is 20 μm, and the sample No. 11 shown in FIG. 1 (B) is each crystal grain: 4 μm. It can be seen that the sample No. 16 shown in FIG. 1 (C) is very fine with each crystal grain: 2 μm to 25 μm and the maximum crystal grain size of 25 μm. In Samples No.1, No.11, and No.16, it can be seen that very fine precipitates are uniformly dispersed in fine crystal grains. And all of sample No. 1-No. 23 have elongation of 5% or more both after solution treatment and after aging treatment, and it can be seen that the samples are excellent in elongation. In particular, it can be seen that Sample No. 11 and Sample No. 16 containing Zr and Mn have extremely excellent elongation of 9% and 11% after aging treatment.

  On the other hand, Sample No. 102 containing none of Cu, Fe, Cr, Mn and Zr has a maximum crystal grain size of 300 μm, and the crystal is very coarse as shown in FIG. It can be seen that the variation is also large (each crystal grain: 50 μm to 300 μm). And as shown in Table 3, sample No. 102 has a very small elongation after aging treatment (0.3%), and it can be seen that it has substantially no elongation.

  Samples No. 1 to No. 23 are both high in tensile strength, 150 MPa or higher, high in conductivity, and satisfy 40% IACS or higher, both after solution treatment and after aging treatment. . In particular, if the temperature during the aging treatment is low (180 ° C. or less), the strength is improved by age hardening, and if the temperature is high (above 180 ° C.), the conductivity is improved due to precipitation of precipitates. I can see that. On the other hand, Sample No. 101 and No. 102 which do not contain any of Cu, Fe, Cr, Mn and Zr have the same electrical conductivity as Sample No. 1 after aging treatment, but have low strength and elongation. .

  Moreover, it turns out that intensity | strength and elongation can be improved or electrical conductivity can be improved by adjusting the temperature at the time of an aging treatment from this test. For sample No. 1, when the temperature of the aging treatment was set to 350 ° C., the sample was softened and the elongation increased to 11%, but the tensile strength was 121 MPa, and sufficient strength could not be obtained. Therefore, it can be said that the temperature during the aging treatment is preferably 100 ° C. or more and 300 ° C. or less.

  As described above, it is made of an Al-Mg-Si alloy containing at least one of the specific elements: Cu, Fe, Cr, Mn and Zr in a specific range, so that the maximum grain size is 50 μm or less. It can be seen that an Al alloy wire having high strength, high electrical conductivity, and excellent elongation can be obtained even though it is an ultrathin wire having a wire diameter of φ0.5 mm or less. By having sufficient elongation in this way, this Al alloy wire is excellent in impact resistance and bending characteristics, and also has a high strength and electrical conductivity, for example, a conductor for electric wires in an in-vehicle wire harness. It is expected that it can be suitably used. In addition, when the stranded wire and the compressed wire made of the above-mentioned ultrafine wires are used, the strands constituting the stranded wire and the compressed wire maintain the composition, structure, and mechanical properties of the Al alloy wire. The wire has high strength, high electrical conductivity and excellent elongation, and by twisting, it can be made into a conductor for electric wire that is further excellent in impact resistance and bending characteristics.

[Test Example 2]
An Al alloy wire was produced and the high temperature characteristics of the Al alloy wire were investigated.

  In this test, an Al alloy wire was produced in the same procedure as in Test Example 1, using an Al alloy molten metal containing the additive element (content: mass%) shown in Table 5. Specifically, the process from melting → continuous casting and rolling (φ9.5mm) → homogenization (530 ° C × 5 hours, cooling rate: 0.89 ° C / min) → wire drawing (φ0.3mm) is the same as in Test Example 1. Conditions.

  The obtained final wire diameter: φ0.3 mm wire solution is subjected to solution treatment by any one of continuous processing methods of electric heating, high frequency induction heating, and furnace type using a pipe furnace to obtain a solid solution wire. Produced. The solution conditions are shown below. Note that the temperature of the wire during the solution treatment was about 600 ° C. (450 ° C. or higher). Further, after heating for solution treatment, it was rapidly cooled using a water tank in the same manner as in Test Example 1 (cooling rate: 500 ° C./min (100 ° C./min or more)).

(Solution conditions)
Electrical heating: Select from linear speed 50m / min to 200m / min, select from current value 33A to 66A,
Distance to water tank 1.6m
High frequency heating: Select from linear speed 200m / min to 1000m / min, current value 100A,
Distance to water tank 1.6m
Furnace type: Select from linear speed 4m / min to 8m / min, select from pipe furnace temperature 580 ℃ ~ 620 ℃,
Distance to water tank 2m

  The obtained solid solution wire was subjected to aging treatment at various temperatures (° C.) shown in Table 6 using a box furnace in the same manner as in Test Example 1 to produce an aging wire (Al alloy wire). The holding time was 12 hours for all, and after heating, cooling was performed in the atmosphere.

  Sample No. 2-101 containing no Si was prepared as a comparative wire. Sample No. 2-101 was subjected to softening treatment (350 ° C. × 3 hours) after wire drawing, and neither solution treatment nor aging was performed.

  About the obtained aging wire (Al alloy wire) and the comparative wire, the maximum crystal grain size (μm), tensile strength (MPa) at room temperature (25 ° C here), elongation (%), conductivity (% IACS) Was examined in the same manner as in Test Example 1. The results are shown in Table 6. Note that the maximum crystal grain sizes shown in Tables 7 to 9 described later are the measurement results of the aging wire (Al alloy wire) and the comparative wire.

  Similar to Test Example 1, each of Sample Nos. 2-1 to 2-9 containing a specific element: Cu, Fe, Cr, Mn, Zr has a microstructure with a maximum crystal grain size of 50 μm or less. It has a tensile strength of 150 MPa or more (both in this case 200 MPa or more), an elongation of 5% or more, and excellent mechanical properties at room temperature. In addition, it can be seen that the samples No. 2-1 to No. 2-9 all have a conductivity of 40% IACS or more (here, 48% IACS or more), and also have high conductivity.

  Furthermore, for the obtained aging wire (Al alloy wire) and comparative wire, tensile strength (MPa) at a temperature (° C) selected from a temperature range of 80 ° C to 150 ° C: Table 7, 80 ° C to 150 ° C Tensile strength (MPa) after holding for 1,000 hours at a temperature (° C) selected from a temperature range of: After holding for 3,000 hours at a temperature (° C) selected from a temperature range of 80 ° C to 150 ° C in Table 8. Tensile strength (MPa): Table 9 was examined. The results are shown in Tables 7-9. The measurement was performed using a general-purpose tensile tester (having an atmospheric furnace) capable of measuring the tensile strength at a temperature selected from the above temperature range. For the measurement of the high-temperature strength shown in Table 7, for example, Japan Copper and Brass Association Technical Standard JCBA T313 (2002), JIS G 0567 (High-temperature tensile test method for steel materials and heat-resistant alloys 1998) can be referred to. . The tensile strength after holding for 1,000 hours at the temperature (° C) shown in Table 8 and the tensile strength after holding for 3,000 hours at the temperature (° C) shown in Table 9 are both room temperature after a predetermined holding time has elapsed. Measured after cooling.

  As shown in Table 7, it contains a specific element: Cu, Fe, Cr, Mn, Zr, has a structure with a maximum crystal grain size of 50 μm or less, excellent tensile strength and elongation at room temperature, and high conductivity It can be seen that the Al alloy wire having a modulus has an excellent tensile strength at an arbitrary temperature selected from 80 ° C. to 150 ° C. and is excellent in high temperature strength. The reason for this is that although the maximum crystal grain size is 50 μm or less as described above, it is composed of a structure that is somewhat large in size (here, the maximum crystal grain size is about 30 μm to 40 μm), thereby causing grain boundary sliding. This is thought to be due to the fact that this was suppressed. In addition, this test has a tensile strength of over 200 MPa at 80 ° C. Although the tensile strength decreases to some extent as the measurement temperature is higher, it has a tensile strength of 150 MPa or higher even at a very high temperature of 150 ° C. You can see that From this, the Al alloy wire excellent in high-temperature strength as described above is an arbitrary temperature selected from the temperature range of 80 ° C to 150 ° C (for example, 80 ° C, 85 ° C, 100 ° C, 120 ° C, 125 ° C, Of course, the tensile strength at any temperature from room temperature to 150 ° C. is considered to be 150 MPa or more.

  In addition, as shown in Table 8, it contains a specific element: Cu, Fe, Cr, Mn, Zr, has a microstructure with a maximum crystal grain size of 50 μm or less, excellent in tensile strength and elongation at room temperature, It can be seen that the Al alloy wire having a high conductivity has a tensile strength of 150 MPa or more after being held at an arbitrary temperature selected from 80 ° C. to 150 ° C. for 1,000 hours, and is excellent in strength after being held at a high temperature. The reason for this is that even when exposed to a high temperature for a long time, the growth of crystal grains is suppressed by containing the above-mentioned specific elements, and a fine structure (typically a structure having a maximum crystal grain size of 50 μm or less). ) Could be maintained. Focusing on sample No. 2-2, the higher the temperature in the temperature range of 80 ° C to 150 ° C, the lower the tensile strength, but at any temperature within that temperature range, 150 MPa or more (here over 200 MPa) It can be seen that it has a tensile strength of From this, the Al alloy wire of sample No. 2-2 is an arbitrary temperature selected from a temperature range of 80 ° C. to 150 ° C. (for example, 80 ° C., 85 ° C., 100 ° C., 120 ° C., 125 ° C., 150 ° C. It is considered that the tensile strength after being held at an arbitrary temperature from room temperature to 150 ° C. for 1,000 hours is 150 MPa or more.

  Furthermore, as shown in Table 9, Sample No. 2-2 maintains a high strength because the tensile strength after 3,000 hours and the tensile strength after 1,000 hours are substantially equal. From this, the Al alloy wire having a strength of 150 MPa or more after holding at an arbitrary temperature selected from the temperature range of 80 ° C. to 150 ° C. for 1,000 hours is high even when exposed to the temperature for a longer time. It is considered that the strength can be maintained. And this reason is considered because the growth of the crystal grain was suppressed by containing the above-mentioned specific element as mentioned above.

  In addition, when Table 7 and Table 8 are compared, the tensile strength after holding at 150 ° C. for 1,000 hours is higher than the tensile strength at 150 ° C. The reason for this is that the tensile strength after holding at 150 ° C. for 1,000 hours is measured after cooling to room temperature after a predetermined time. Another reason is considered to be that after being exposed to a high temperature for a long time, it was aged after the fact and strengthened by uniform dispersion of precipitates. From this, the Al alloy wire having a tensile strength of 150 MPa or more at an arbitrary temperature selected from a temperature range of 80 ° C. to 150 ° C. can be such a high temperature and a low temperature state from a high temperature state to about room temperature. In a use environment that can become high, it is expected that high strength will be maintained over time or the strength will be further improved.

  Samples No. 2-1, No. 2-3 to No. 2-9 all have a tensile strength of 150 MPa or more (here, 200 MPa or more) after being held at 150 ° C. for 1,000 hours. It can be seen that, as with sample No. 2-2, the strength after holding at high temperature is excellent. Sample No.2-1, No.2-3 to No.2-9 are all selected from the temperature range of 80 ° C to 150 ° C as in Sample No.2-2. The tensile strength after being held at a temperature of 1,000 hours for 1,000 hours and the tensile strength after being held at an arbitrary temperature from room temperature to 150 ° C. for 1,000 hours is 150 MPa or more, (2) any of the above selected It is expected that the tensile strength after further holding for 3,000 hours at the temperature is 150 MPa or more, and (3) the strength may be improved by exposure to any temperature selected above during use.

  Note that the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the gist of the present invention. For example, the composition of the Al alloy, the wire diameter of the Al alloy wire, the solution treatment conditions, and the like may be changed within a specific range.

  The aluminum alloy wire of the present invention and the twisted aluminum alloy wire of the present invention are lightweight, have high strength and high electrical conductivity, and are also desired to have excellent impact resistance and bending properties, such as automobiles and airplanes. It can be suitably used for conductors of electric wires used in the wiring structures of various electric devices such as transport devices and control devices such as industrial robots. Moreover, this invention aluminum alloy wire and this invention aluminum alloy strand wire can be utilized suitably for the conductor of the electric wire of the use where it is desired to be excellent also in high temperature strength and heat resistance. The coated electric wire of the present invention can be suitably used for electric wires used in the wiring structures of various electric devices such as in-vehicle wire harnesses. The wire harness of the present invention can be used in various fields of electrical equipment where weight reduction is desired, particularly in automobile wiring structures where further weight reduction is desired to improve fuel economy and places that can be hot such as around the engine. It can be suitably used for a wiring structure of an automobile.

Claims (9)

An aluminum alloy wire used for a conductor,
% By mass
Mg is 0.03% to 1.5%,
Si is 0.02% or more and 2.0% or less,
Containing at least one element selected from Cu, Fe, Cr, Mn and Zr in a total of 0.1% to 1.0%, with the balance being Al and impurities,
Conductivity is over 40% IACS,
Tensile strength is 150 MPa or more,
Elongation more than 5%,
Wire diameter is 0.5mm or less, and
Aluminum alloy wire with a maximum grain size of 50 μm or less.   2. The aluminum alloy wire according to claim 1, which contains 0.01% by mass or more of Zr.   3. The aluminum alloy wire according to claim 1, comprising 0.01% by mass or more of Mn.   The aluminum alloy wire according to any one of claims 1 to 3, wherein the tensile strength after holding at an arbitrary temperature selected from a temperature range of 80 ° C or higher and 150 ° C or lower for 1,000 hours is 150 MPa or higher.   The aluminum alloy wire according to any one of claims 1 to 4, wherein a tensile strength at an arbitrary temperature selected from a temperature range of 80 ° C to 150 ° C is 150 MPa or more.   The aluminum alloy wire according to any one of claims 1 to 5, further comprising at least one element of 0.08% or less of Ti and 0.016% or less of B by mass%.   An aluminum alloy stranded wire formed by twisting a plurality of the aluminum alloy wires according to any one of claims 1 to 6.   The aluminum alloy wire according to any one of claims 1 to 6, the aluminum alloy twisted wire obtained by twisting a plurality of aluminum alloy wires according to any one of claims 1 to 6, or the stranded wire is compressed. A covered electric wire that uses any one of the formed compressed wire rods as a conductor and has an insulating coating layer on its outer periphery.   9. A wire harness comprising the covered electric wire according to claim 8 and a terminal portion attached to an end portion of the electric wire.