JPH0917237A - Copper or copper alloy sheathed aluminum alloy wire - Google Patents

Abstract

PURPOSE: To provide the copper or copper alloy sheathed aluminum alloy wire which is light in weight, high in conductivity, and superior in wire drawing processing by sheathing a high strength aluminum alloy core member the tension strength and conductivity of which are equal to or more than each specified value, with copper or a copper alloy layer with a specified space factor maintained. CONSTITUTION: Sheathing material composed of oxygen free copper is sheathed over a core member by a roll forming process in such a way that a copper space factor is 10 to 20% in which the core member is composed of a high strength aluminum alloy wire where its tension strength is equal to or more than 24kgf/mm<2> , and its conductivity is less than 58% IACS. The core member is high in strength, and superior in wire drawing processing as compared with a normal conductive aluminum wire. Namely, the occurrence of troubles such as entanglement and the like and the number of disconnection can thereby be reduced. Pressure acting as driving force for joining in an interface between an alloy wire and a surface copper material layer, can be made high, joining takes place between them in an early stage, troubles such as peeling of the copper material layer can thereby be lessened when the alloy wire is bent so as to be deformed at the time of wire drawing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper or copper alloy-coated aluminum alloy wire used for a pickup coil for a hard disk, a center conductor for a CATV or a winding for a headphone, and is particularly lightweight and has high conductivity. The present invention relates to a copper or copper alloy coated aluminum alloy wire.

[0002]

2. Description of the Related Art Conventionally, a copper-coated aluminum wire, which is lighter than a copper wire and which is required to have high conductivity, is used as a pickup coil for a hard disk, a center conductor for a CATV, or a winding for a headphone. Is used.

This copper-clad aluminum wire is usually prepared by vertically preliminarily attaching a pre-treated copper tape which has been subjected to washing and polishing to the same pre-treated aluminum tape and covering the aluminum wire. Is continuously formed into a tubular shape by roll forming, the abutting portions of the copper tape are continuously welded, and then wire drawing is performed to a predetermined diameter. Generally, when the aluminum tape is covered with the copper tape by roll forming, there is no adhesiveness between the surface copper layer and the aluminum wire, and the two are brought into close contact with each other by the wire drawing process in the next step. Further, the copper-coated aluminum wire is drawn into ultrafine wires of several tens to several hundreds of μm and provided for various purposes.

Generally, a copper tape used for producing a copper-coated aluminum wire has an oxygen content of 10 ppm with excellent weldability.
The aluminum wire is made of the following oxygen-free copper, and has a highest conductivity of 62% IACS or more and is a pure aluminum wire for conductivity. As shown in Table 1, in consideration of the balance between weight reduction and conductivity, pure aluminum wire and copper tape are compounded so that the cross-sectional area ratio of copper and aluminum is usually 10 to 20%. A coated aluminum wire is manufactured.

[0005]

[Table 1]

[0006]

However, the above-mentioned copper-coated aluminum wire has the following problems.
Conventionally, the diameter of a copper-coated aluminum wire is about 50 μm, which is the smallest even if it is thinned by wire drawing, and has a larger diameter than a copper ultrafine wire having a diameter of about 10 to 30 μm. Also, the production amount of copper-coated aluminum wire (the amount that can be taken per strip length without breaking) was extremely small. These problems, since the core material is formed of a pure aluminum wire to reduce the weight, the strength as a copper-coated aluminum wire is low, handling during wire drawing,
Being extremely delicate compared to copper ultrafine wire,
Due to the low adhesion (bondability) between the surface copper layer and the pure aluminum wire, the surface copper layer peels off from the pure aluminum wire during wire drawing and the pure aluminum wire is exposed and broken. It is a thing.

Conventionally, in order to solve these problems,
Optimization of wire drawing conditions and management of handling work are performed, and cleaning and pretreatment of both materials are strengthened before roll forming to improve adhesion between copper tape and pure aluminum wire. However, improvement of wire drawing workability and increase of production amount are still insufficient,
The cost of the product is increasing.

The present invention has been made in view of the above problems, and it is lightweight and highly conductive, and is a copper or copper alloy-coated aluminum alloy wire having a better drawability than a copper-coated aluminum wire. The purpose is to provide.

[0009]

The copper or copper alloy-coated aluminum alloy wire according to the present invention has a tensile strength of 24 kgf /
mm ² or more, core material made of high-strength aluminum alloy wire having conductivity of 58% IACS or more, and the space factor of the core material 1
It is characterized by having a copper or copper alloy layer covered with 0 to 20%.

[0010]

[Function] Hereinafter, copper and copper alloys are collectively referred to as a copper material. The copper-clad aluminum alloy wire according to the present invention is a high-strength aluminum alloy wire (tensile strength of 24 kgf /
The core material is formed of an aluminum alloy wire having a conductivity of 58% IACS or more (mm ² or more).

When the core material is formed of a high-strength aluminum alloy wire, it has higher strength and is excellent in wire drawing workability as compared with a core material formed of a normal pure aluminum wire for conduction. For this reason, the occurrence of troubles such as entanglement of lines is reduced. In addition, since it is possible to endure abnormal tension during wire drawing, the number of wire breaks is reduced.

Further, since the high-strength aluminum alloy wire is harder than a normal pure aluminum wire for conduction, when the copper wire is coated and then drawn, the aluminum alloy wire as the core material and the surface copper material layer At the interface with and, the pressure that is the driving force for joining becomes high, and the early stage of wire drawing (low workability)
Then, a bond occurs between the two. Therefore, in the subsequent step of drawing the copper material-coated aluminum alloy wire into an ultrafine wire, the load of wire drawing stress on the surface copper material layer can be reduced, and the surface copper material layer peels off especially during bending deformation. Then
Problems such as exposure of the aluminum alloy wire can be reduced.

Since the core material is made of a high-strength aluminum alloy wire, as the surface copper material layer becomes thinner,
The electrical conductivity and tensile strength of the copper-coated aluminum alloy wire according to the present invention decrease and approach those values of high strength aluminum alloy. Therefore, the lower limits of conductivity and tensile strength are
The values are 58% IACS and 24 kgf / mm ² , respectively.

[0014]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples. Table 1 shows Example 1 and Comparative Examples 1-2.
The type, tensile strength and conductivity of the core material used in the production of The copper material-coated aluminum alloy wire according to the present invention (Example 1) is a roll forming method in which a high-strength aluminum alloy wire defined by the tensile strength and conductivity in Table 2 is coated with oxygen-free copper. According to the above, it is manufactured by coating so that the copper space factor becomes 15%. On the other hand, Comparative Examples 1 and 2 are pure aluminum wires for conduction or aluminum alloy wire No. A having the characteristics shown in Table 2, as in Example 1.
It is manufactured by coating a coating material made of oxygen-free copper by a roll forming method so that the copper space factor becomes 15%.

Each of the obtained composite wires was drawn to a surface reduction rate of 99.9%, and then the tensile strength and the electrical conductivity were measured.
In addition, by conducting a tensile test on each composite wire during wire drawing, and observing the fracture surface, it is checked whether the covering material and the core material are integrated, that is, they are not separated, and peeled. The range of the area reduction rate at which the occurrence of the phenomenon did not occur was calculated for each composite line. Furthermore, each composite wire with a weight of 100 kg was drawn to a diameter of 50 μm, and the production amount was examined. The results obtained are shown in Table 3 below.

[0016]

[Table 2]

[0017]

[Table 3]

Example 1 has a conductivity of 5 compared with Comparative Example 1.
%, But the tensile strength is increased by about 23%. In addition, since the joining of the surface copper material layer and the high-strength aluminum alloy wire occurs even at the stage of the low workability of wire drawing, the production amount of Example 1 jumps to 5 times that of Comparative Example 1. Is growing. Further, in Comparative Example 2, since the aluminum wire No. A as the core material has high strength, the bonding strength between the surface copper material layer and the aluminum alloy wire No. A is high, and the production amount is large, but the conductivity is high. It is too low to be used as a winding wire.

[0019]

As described above in detail, according to the present invention, since the core material is formed of a high-strength aluminum alloy wire, a lightweight or highly conductive copper or copper alloy-coated aluminum alloy wire is obtained. be able to.

Claims (1)

[Claims] 1. A core material made of a high-strength aluminum alloy wire having a tensile strength of 24 kgf / mm ² or more and an electrical conductivity of 58% IACS or more, and copper covering the core material with a space factor of 10 to 20% or A copper or copper alloy-coated aluminum alloy wire comprising a copper alloy layer.