JPS6046495B2 - Manufacturing method of high heat-resistant aluminum electric wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an aluminum electric wire having a steel core in the strand, which has high heat resistance and low core loss and skin effect.

BACKGROUND ART In recent years, with the increase in power consumption, there has been a desire to realize aluminum-based electric wires with high heat resistance that can withstand high temperatures due to increased power transmission capacity.

As this type of aluminum electric wire, one using an aluminum alloy made by adding a small amount of zirconium to aluminum is known, but this type of aluminum alloy wire has a normal operating temperature of at most 1.
Since the temperature is around 00°C, we cannot expect a significant increase in power transmission capacity. On the other hand, extruded rods coated with aluminum by extrusion onto a steel core are cold-worked to reduce the diameter to a specified wire diameter, and can be used at temperatures around 3000C, which is the softening temperature of the steel core. Although it is possible, when these are twisted together, there are drawbacks such as core loss due to the magnetic nature of the core, current distribution, and no current flowing inside the stranded wires, resulting in a large skin effect. The present invention was made in order to eliminate such conventional drawbacks, and is made by extrusion coating the outer periphery of a non-magnetic steel wire with aluminum having a purity of 99% or more so that the cross-sectional area ratio to the steel wire is 8 or more. Reducing the extruded rod to a predetermined wire diameter by cold wire drawing, and twisting the thus obtained multiple strands of strands alone or around the outer periphery of reinforcing steel wire. The present invention aims to provide a method for producing an aluminum electric wire having a steel core in the strand, which has high heat resistance, low iron loss and small skin effect, and has a steel core in the strand.

As the non-magnetic steel wire used in the present invention, ordinary stainless steel (Cr 12-18%, Ni 7-10%, Co, 2%
Below, the remainder is Fe) or recently developed high manganese stainless steel.

Further, as the aluminum used in the present invention, in addition to ordinary conductive aluminum, alloy aluminum to which a small amount of Zr, Fe) CUNSi and other elements are added can also be used.

However, even when aluminum alloy is used, the purity of the aluminum needs to be 99% or more in order to maintain high conductivity. In the method for manufacturing an aluminum electric wire of the present invention, aluminum is first extruded and coated onto the above-mentioned non-magnetic steel wire.

At this time, in order to improve the adhesion between the non-magnetic steel wire and aluminum, the non-magnetic steel wire is degreased, and a gap is provided between the extruder die and the nipple, and the aluminum is transferred onto the non-magnetic steel wire. Make sure that it is sufficiently crimped. Incidentally, instead of providing a gap between the die and the nipple, a 2- to 4-way roll die may be arranged just before the extruder to squeeze the aluminum coating. The cross-sectional area ratio of the non-magnetic steel wire to the aluminum coating is usually desirably 1:10 or more.

When the cross-sectional area ratio of the aluminum coating becomes less than 1, it generally becomes difficult to perform expansion and contraction processing. However, if a reverse tension wire drawing machine is used, the above ratio can be increased to 1:8. In this range, extruded rods can be processed at 20 to 30 per bath using a cold die without the need for special equipment.
% filtration area reduction rate, it is possible to draw wire up to 90% area reduction rate. The upper limit of the cross-sectional area ratio of the aluminum coating to the non-magnetic steel wire is not particularly limited, and is appropriately selected from the viewpoints of mechanical strength, extrusion processing technology, and cost required for the aluminum electric wire. The strands obtained by cold wire processing may be concentrically twisted as they are, or may be twisted with reinforcing wires to form a copper-core reinforced type, as in ACSR.

In this case, when twisting a small number of strands such as 3 or 4 strands, the strands and the reinforcing wire can be twisted by replacing one of the strands with a reinforcing wire. Suitable reinforcing wires include galvanized copper wire, aluminized steel wire, aluminum weld wire, and stranded wires thereof.

Since the aluminum electric wire obtained in this way has a steel core embedded in each strand, the rate of decrease in strength at high temperatures is small, and even if the strength of the aluminum itself decreases, the steel wire will eventually become a steel wire. Since it bears the burden of strength, it will not drop below a certain value.

In addition, the heat-resistant temperature range is 30°C, which is difficult to achieve with aluminum alloys.
It is possible to expand the temperature to about 0℃. Furthermore, in the present invention, since a non-magnetic steel wire is used as the steel core, the degree of iron loss and current distribution is small compared to the case where a general steel wire is used, and power transmission loss can be suppressed to a small level.

Next, examples will be described.

Example 2. 304 series stainless steel wire (Crl8
%, Nl 8%) was degreased by a conventional method, and then conductive aluminum was extruded and coated thereon to have an outer diameter of 12 mm.

The rod extruded in this manner is subjected to a drawing process using a three-way roll die placed in front of the extruder, and then cold wire drawn using cold dies at an area reduction rate of 20 to 30% per die.4. A strand of 2Tf$tφ was used (area reduction rate tin%).
The strength of this wire is as follows. Also, this wire is 7
Twist them together to create a DC resistance (RDO) and an AC (commercial frequency) resistance.

Claims (1)

[Claims] 1. The outer periphery of the non-magnetic steel wire has a cross-sectional area ratio of 8 to the steel wire.
An extruded rod made of extrusion coated aluminum with a purity of 99% or more is reduced in diameter to a predetermined wire diameter by cold wire drawing, and multiple strands of the thus obtained strands are made into individual strands. A method for producing a highly heat-resistant aluminum electric wire, which is characterized by twisting the electric wire around the outer periphery of reinforcing steel wire. 2. The method for manufacturing a highly heat-resistant aluminum electric wire according to claim 1, wherein the area reduction rate of the extruded rod due to cold wire drawing is less than 90%.