JPS6319714A - Manufacture of conductor for covered wire - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for manufacturing a conductor for a covered electric wire that is insulated with polyethylene or the like, and particularly relates to a method for manufacturing a conductor for a covered electric wire that is installed between utility poles, etc. .

[Prior Art] Hard copper wire (a wire made from cold-drawn tough pitch copper or oxygen-free copper) has traditionally been used as a conductor for overhead distribution lines installed between utility poles. A plurality of assembled hard copper wires are twisted together, and an insulating coating made of polyethylene, polyvinyl chloride, or the like is applied to the twisted wires. In addition, there is also one that uses a hard copper wire as a single wire and has an insulating coating applied to the single wire.

[Problems to be solved by the invention When cold wire drawing is applied to Kotafu pitch copper or oxygen-free copper,
Residual stress often exists on the surface of the obtained wire. The residual stress includes, in particular, tensile residual stress. Further, on the surface of each twisted hard copper wire, a stranded wire repulsion force that tends to untwist is inevitably generated. This twisted wire repulsive force appears as tensile residual stress on the surface of each hard copper wire. Furthermore, each hard copper wire may have residual stress due to curling curls formed when it was wound around a drum.

In conventional coated electric wires, the residual stress as described above may be one of the causes of wire breakage.

That is, when rainwater enters the covered wire, the inside of the coating layer becomes a corrosive environment, and an oxide film is formed on the surface of the hard copper wire. When such a corrosive environment and the above-mentioned residual stress interact with each other, stress corrosion cracking occurs in the hard copper wire, resulting in wire breakage.

If an annealed copper wire is used as the conductor for the covered electric wire, the residual stress as described above is small, so that the possibility of stress corrosion cracking occurring is reduced. However, on the other hand, the tensile strength inevitably decreases, and therefore, in practice, annealed copper wire cannot be used as a conductor for coated wires.

In order to obtain conductor wires with excellent corrosion resistance, it is possible to electroplate Am, Zn, Sn, Ni, etc. on the surface of hard copper wires. However, if the coating layer is formed by plating, pinholes are likely to occur in the coating layer. If such a pinhole exists, when the conductor wire is placed in a corrosive atmosphere, the pinhole portion will be intensively corroded, and stress corrosion cracking may occur in that portion. Furthermore, since dissimilar metals are plated, electrolytic corrosion may occur between the copper and the plated metal.

Therefore, an object of the present invention is to provide a manufacturing method capable of obtaining a conductor for a coated electric wire that maintains tensile strength and does not cause stress corrosion cracking.

[Means for Solving the Problems] and [Operations and Effects] As shown in FIG. N5Ar is applied to the surface of the conductor 1 on which the wire-processed structure is formed.
, Ne, and He. In FIG. 1, the ion implantation layer is designated by reference number 2.

By ion-implanting one or more elements selected from the group including N, Ar, Ne, and He into the conductor surface, the residual stress existing on the conductor surface is alleviated and stress corrosion cracking resistance is improved. Improve your sexuality. Also, unlike the plating method,
There are no pinholes in the surface layer formed by ion implantation, and its adhesion strength is high. Therefore, the conductor has excellent corrosion resistance, and the corrosion resistance does not deteriorate locally. Furthermore, since there are no dissimilar metals present, there is no risk of electrolytic corrosion occurring. Moreover, since there is no contamination of the copper conductor, it is advantageous for recycling.

The conductor to be ion-implanted is mainly made of copper and has a drawn wire structure extending in the longitudinal direction. Therefore, the conductor has a relatively high tensile strength and can maintain a tensile strength sufficient to withstand use as a conductor for a covered electric wire. 1 selected from the group containing N, Ar, Ne, He
The ion-implanted layer consisting of a species or two or more elements does not impair the connection characteristics of the copper-based conductor.

A conductor 1 on which an ion-implanted layer 2 is formed as shown in FIG.
A plurality of wires are twisted together, and an insulating coating is applied to the twisted wires. Alternatively, the conductor 1 shown in FIG. 1 may be used as a single wire, and an insulating coating may be applied to the single wire.

Note that the conductor to be ion-implanted is not limited to a single wire. For example, as shown in FIG.
are twisted together, and 8% Ar, Ne,
One or more elements selected from the group including He may be ion-implanted. In FIG. 2, the ion implantation layer is designated by reference number 4.

Furthermore, the conductor to be ion-implanted need not be a round wire, but may be, for example, a tape-shaped material.

As described above, according to the present invention, it is possible to obtain a conductor for a covered electric wire that maintains tensile strength and does not cause stress corrosion cracking.

[Examples] (1) Example 1 A conductor having the structure shown in FIG. 1 was manufactured. That is, diameter 2
N ions were implanted into the surface of a tough pitch copper wire with a tensile strength of 48 kg/mm 2 at an acceleration voltage of 50 KeV.

At this time, the N atom concentration was set to be 10% or more within a region with a surface thickness of 0.2 μm.

The tensile strength of the tough pitch copper wire thus obtained was almost the same as that before N ion implantation.

Further, almost no decrease in conductivity was observed after ion implantation.

For the conductor obtained as described above, a tensile stress of 2
When a stress corrosion cracking test was conducted using an ammonia aqueous solution at 0 kg/mm2, the wire did not break even after twice the breaking time of conventional tough pitch copper wire.

(2) Example 2 The cross-sectional structure is schematically shown in FIG. 3, and the thickness is 0. 25mm
, He and Ne were ion-implanted at an accelerating voltage of 150 KeV into a region with a thickness of 0 □ 1 μm on one side surface of a beryllium copper alloy tape 5 having a width of 25 mm. In FIG. 3, the ion implantation layer is designated by reference number 6.

The tape thus obtained was bent and restrained into a U-shape with a curvature of 12.5H so that the ion-implanted side was on the outside.
It was left in an ammonia vapor atmosphere. For comparison, a beryllium-copper alloy tape without ion implantation was similarly bent into a U-shape, restrained, and left in an ammonia vapor atmosphere. As a result, the ion-implanted tape still did not fracture even after three times the time that the comparative sample fractured due to stress corrosion cracking.

Note that when the beryllium copper alloy tape obtained by the method of the present invention was used as a conductor connector, the connection characteristics were good.

(3) Example 3 As the cross-sectional structure is schematically shown in FIG. 4, 19 conductor strands 7 made of tough pitch copper were twisted together, and Ar ions were implanted into the surface of the stranded conductor at an accelerating voltage of 200 KeV. did. The ion-implanted portion is within a region approximately 0.2 μm thick at the externally exposed surface.

The stranded wire conductor thus obtained was subjected to the following stress corrosion cracking test with its twisted shape restrained at both ends.

Applied stress = 20 kg/mm2 Solution used: NH, Cα 53.5 g/ICuCIL
2 ・2H20 4.26g/store Ammonia water 21cc/store Test method: Immerse the lower end of the stranded conductor in the above solution,
A stress corrosion cracking test was conducted at a cycle of 70'C, 36 hours = normal temperature, 18 hours.

For comparison, a stress corrosion cracking test was conducted under the same conditions on a stranded wire conductor of the same shape made of tough pitch copper without ion implantation. In this comparative sample, stress corrosion cracking occurred in the outermost layer of strands after 48 days. However, the stranded wire conductor according to the present invention having an ion-implanted layer on its surface did not suffer from stress corrosion cracking even after 96 days.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing an example of a conductor obtained by the method of the present invention. FIG. 2 is a cross-sectional view schematically showing another example of a conductor obtained by the method of the present invention. FIG. 3 is a cross-sectional view schematically showing still another example of a conductor obtained by the method of the present invention. FIG. 4 is a cross-sectional view schematically showing still another example of a conductor obtained by the method of the present invention. In the figure, 1 indicates a conductor and 2 indicates an ion-implanted layer.

Claims (3)

[Claims] (1) N, Ar, Ne, H
A method for manufacturing a conductor for a covered electric wire, the method comprising ion-implanting one or more elements selected from the group including e. (2) The method for manufacturing a covered electric wire conductor according to claim 1, wherein the conductor is a single wire conductor. (3) The method for manufacturing a conductor for a covered electric wire according to claim 1, wherein the conductor is a stranded wire conductor.