JPS6056431A - Method for removing residual stress of solid wire of twisted wire of hard drawn copper wire - Google Patents

Abstract

PURPOSE:To remove residual stress effectively over whole periphery of the surface of a hard drawn copper wire conductor by giving rotatory bending distortion by passing solid wire or twisted wire of the hard drawn copper wire through a rotary body having deviated center of axis. CONSTITUTION:The hard drawn copper wire (solid wire, twisted wire or these insulating covered wire) from which residual stress is to be removed is passed continuously in the direction of the arrow through a fixing member and through holes 3, 6, 3', 6' and 3'' of the rotary bodies, and meanwhile, the rotary bodies 5 and 5' are rotated in the same direction. Accordingly, the hard drawn copper wire 1 is pulled at a fixed speed while rotating on its own axis. At this time, the rotatory bending distortion is given to the wire by rotary bodies 5, 5' having deviated center of axis. Accordingly, the plastic distortion is generated in all radial direction of the wire, and the residual stress is removed almost perfectly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing residual stress from solid or stranded hard copper wire. In particular, the present invention is 41J! The present invention relates to a method for removing residual stress by applying plastic strain to a single or stranded 11IIN wire directly or with an insulating coating applied thereto.

Conventionally, in the field of overhead insulated Id lines, particularly hard copper wires are used as conductors. Hard copper wire has high residual stress on its surface during its manufacturing process, overhead line process, etc., and this is a cause of stress corrosion cracking of overhead insulated wires. Therefore, in order to prevent stress corrosion cracking, it is possible to remove the residual stress generated on the surface of the single wire, stranded wire, or their sheathed conductor.

Conventionally, compressed electric wires have been used to remove such residual stress, but there have been economical problems such as the need to develop new accessories. Furthermore, it has been proposed to remove residual stress by a roll straightening method, but such a method eliminates residual stress over the entire circumference of the cotton bodies that make up solid copper wire, stranded wire, and their coated wires. The disadvantage is that it cannot be completely removed.

As a result of various studies under the above-mentioned circumstances, the inventors of the present invention have found that residual stress is generated over the entire circumference of the conductor surface of the hard copper wire by passing through a rotating body whose center of the wire axis is biased and applying rotational bending strain to the hard copper wire. The present invention has been achieved based on the discovery that this can be effectively removed.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for removing residual stresses in solid or stranded hard copper wire without the drawbacks of the prior art described above.

Another object of the present invention is to eliminate residual stress in hard copper wires and prevent stress corrosion cracking in overhead insulated wires.

The above objects of the present invention are achieved by the method of the present invention shown below.

That is, the present invention makes hard copper wire hard by passing a single or stranded hard copper wire directly or in a coated state through at least one rotary body whose wire axis center is biased and rotating the rotary body. This is a method for removing residual stress from a single hard copper wire or a stranded wire, which is characterized by applying plastic strain continuously in the entire radial direction of the copper wire.

Hereinafter, the present invention will be explained with reference to the attached drawings 4 and 4.

FIG. 1 is a side view showing an example of an apparatus for carrying out the method of the present invention, and FIG. 2 is a longitudinal sectional view showing an example of the rotary body.

In FIG. 1, reference numeral 1 indicates a hard copper wire, which may be a single wire or a stranded wire, and may be in an uncoated state or in an insulated state. 2.2' and 2'' are the through holes 3, 3',
and #3 are arranged in a substantially straight line, and are made of a suitable material such as metal, wood, or plastic. The size of each through hole 3.3', 3'' is such that the hard copper wire to be processed (single wire, stranded wire, or coated wire of these, hereinafter simply referred to as hard copper wire) passes through, and as described later, it rotates. It is preferable that the hard copper wire does not shake excessively within the through hole when the body rotates, and it is necessary to prepare each device according to the outer diameter of the wire.

In addition, bearings 4, 4 are provided in each of the through holes 3, 3', 3'' in order to allow the hard copper wire 1 to rotate and pass through each through hole smoothly and to prevent twisting of the wire and surface scratches. ',
4' respectively.

5 and 5 are between the fixing parts U2 and 2' and the fixing member 2'.

The through holes 3, 3' are rotary bodies or rotating jigs whose wire axis centers are offset, and are provided between the through holes 3 and 3'.

The line connecting #6 is the center of rotation of the rotating body, and through holes 6 and 6' similar to the through hole 6 as described above are formed at positions offset from this.
are provided for each. The rotating bodies 5, 5' are made of a suitable material such as metal, wood, plastics, etc., like the fixed members, and for the reasons mentioned above in connection with the through holes 3, etc., the through holes 6, 6' are Preferably, a bearing 7.7' is incorporated. Note that 8 and 8' are rotational axes of each rotating body.

FIG. 2 shows a sectional view of the rotating body 5 in FIG. 1. In this example, the through hole 6 is provided at a position offset from the center of rotation of the circular rotating body, but the rotating body of the present invention is not limited to such a shape, and can be modified in various ways. Any rotating body that is biased and capable of imparting rotational bending strain to a hard copper wire can be used as the rotary body of the present invention.

To carry out the method of the present invention using the above-mentioned apparatus, the hard copper wire (solid wire, stranded wire, or insulated wire thereof) whose residual stress is to be removed is passed through the through holes 3. of the fixed member and the rotating body. 6.5
The rotating bodies 5 and 5' are rotated in the same direction (for example, in the direction of the arrow) while passing continuously through them in the direction of the arrow. Therefore, the hard copper wire 1 is either rotated on its own and taken off at a constant speed, or at this time, rotational bending strain is applied by a rotating body with the center of the wire axis deviated, causing plastic strain in the entire radial direction of the wire, resulting in residual Stress is almost completely removed.

In the above example, the case where two rotating bodies are used is shown, but it goes without saying that one or six or more rotating bodies may be used. Furthermore, when two or more rotating bodies are used, it goes without saying that the rotating directions of the rotating bodies may be reversed.

The degree of plastic strain given to hard copper wire depends on the material of the wire.

The number of rotating bodies, the deviation of the center of the wire axis) The degree of lk 1 The distance between the rotating body and the fixed member 1 The rotational speed of the rotating body, the drawing speed of the wire, etc., but ultimately the plasticity imparted to the hard copper wire It is preferable to select the above factors so that the strain is 0.15 to 6 inches as the bending strain on the wire surface, as is clear from the examples below. That is, when the bending strain is 0.15% or less, the amount of plastic deformation is small, the residual stress removal effect is small, and therefore good corrosion resistance cannot be obtained. Furthermore, if the bending strain is 6% or more, the hard copper wire will be damaged, the conductor will not be deformed uniformly, the formation of pits will be accelerated, and problems will arise in corrosion resistance.

As described above, the present invention is a method for removing residual stress in a hard copper wire by relatively simple means, and also has the following effects.

(1) Residual stress is removed in the entire radial direction of solid copper wire and stranded wire.

(2) The manufacturing technology is easy to manage because the v-preparation is relatively simple.

(3) The equipment used in this method can handle wire rods with the same shape as conventional round stranded wires, so it is economically advantageous to use accessories for wire installation, and The present invention can be implemented by simply improving the V-equipment, and does not require large capital investment.

Next, the following embodiments of the present invention will be described.

Example 1 A rotary bending device for 2.00 hard copper shrunk solid wire as shown in FIGS. 1 and 2 was used to bend 2.0 IC diameter 2.0 IC. Qmm) solid copper wire at a drawing speed of 6Q am/min.

The residual stress was removed by passing through the rotating body at a rotational speed of 20 Or, p, m, and applying plastic strain so that the bending strain on the wire surface (hard I @ strain in the wire axial direction) was 0.1%. A hard copper wire was obtained. The obtained hard copper wire was designated as Sample 1.

Example 2 2.01 as in Example 1! A solid copper wire was treated.

However, in this case, plastic strain was applied so that the wire surface bending strain was 0.16% to obtain a hard copper wire with residual stress removed (Sample 2).

Example 3 A 2.0φ solid copper wire was treated in the same manner as in Example 1.

However, in this case, plastic strain was applied so that the wire surface bending strain was 0.4% to obtain a hard copper wire with residual stress removed (
Sample 3).

Example 4 2. Same as Example 1. Processed Ol solid wire single wire.

However, in this case, plastic strain was applied so that the wire surface bending strain was 5.8%, and a hard copper wire with residual stress removed was obtained (
Sample 4).

Example 5 A 2.0j5 solid copper wire was treated in the same manner as in Example 1.

However, in this case, plastic strain was applied so that the wire surface bending strain was 6.2%, and a hard copper wire with residual stress removed was obtained (
Sample 5).

Comparative Example 1 2.0 without applying the method of the present invention as shown in the above example
1 copper wire was used as a comparative sample (comparative sample 1).

Example 6 A hard copper wire strand (19/2.0) (with a diameter of 2.0 mm) was 19 stranded single wires) at a wire drawing speed of 6
Qcm/min, rotation speed of rotating body 20 Or, p, m
A hard copper wire strand with residual stress removed was obtained by applying plastic strain so that the bending strain on the wire surface (strain in the axial direction of the hard hook wire) was 0.16% (Sample 6). .

Example 7 A hard copper wire strand (19/2.0) was treated in the same manner as in Example 6. However, in this case, plastic strain was applied so that the wire surface bending strain was 0.16% to obtain a stranded wire with residual stress removed (Sample 7).

Example 8 Same as Example 6, 8! ! Copper gland twist # (19/2.0) was processed. However, in this case, the line surface bending strain is 0.4%.
A stranded wire from which residual stress was removed was obtained by applying plastic strain so that the result was (Sample 8).

Example 9 A hard copper wire twist [1 (19/2.0) was treated in the same manner as in Example 6. However, in this case, plastic strain was applied so that the wire surface bending strain was 5.7%, and a stranded wire with residual stress removed was obtained (Sample 9).

Example 10 Hard copper wire strands (19/2.0) were treated in the same manner as in Example 6. However, in this case, plastic strain was applied so that the wire surface bending strain was 6.6%, and a stranded wire with residual stress removed was obtained (Sample 10).

Comparative Example 2 Hard copper wire strands (19/2.
0) was used as a comparative sample (comparative sample 2).

Examples (1) to (10) and comparison (;11 (1') to
The following are the results of the corrosion test when each sample was held in Matson's solution for 200 hours at 70°C and the condition of scratches on the conductor surface by applying each sample obtained in (2). It is shown in Table 1.

From the results in Table 1, the following conclusions can be drawn.

Sample 1 (measured hard copper wire with 0.1% wire surface bending strain) The scratches on the conductor surface are shallow and the product is fully satisfactory, but there are many pits generated due to corrosion and the maximum pit depth is low. Because the strands are deep, their corrosion resistance is poor, making them somewhat unsatisfactory as stress corrosion countermeasures. -Sample 2 (Hard copper wire with wire surface bending strain of 0.L 6%) There are no scratches on the sensor surface as a product, and furthermore, both the number of pits due to corrosion and the maximum depth of pits are significantly higher than that of comparative sample 1. It has been improved and has sufficient performance as a twisted wire adder to prevent stress corrosion.

Sample 3 (measured hard copper wire with 0.4% wire surface bending strain) The conductor can, like sample F42, had no problems as a product, and no pits were observed due to corrosion, and the corrosion resistance was significantly improved. This countermeasure hard copper wire has excellent performance as a stress corrosion countermeasure stranded wire.

Sample 4 (hard copper wire with surface bending strain of 5.8%) The conductor can is the same as samples 2 and 6 and there is no problem, and the corrosion resistance is also the same as sample 6.
It has excellent performance as a stranded wire to prevent stress corrosion.

Sample 5 (measured hard copper wire with 6.2% wire surface bending strain) The conductor can is deep and not suitable for use as a product.

Corrosion resistance is improved compared to comparative sample 1, but sample 2
- Inferior compared to 6. This is because the bit was generated from the conductor i5 because the conductor can was deep. This electric wire is somewhat insufficient as a 3-wire stranded wire to prevent stress corrosion.

From the above results, the remaining Wt has less conductor cans and excellent corrosion resistance.
In order to obtain a stress-relieving hard hook wire, according to the present invention, 0.1
It can be seen that the treatment should be performed to give a linear surface bending strain of 5% to 6%.

Sample 6 (hard copper wire stranded wire with 0.13% wire surface bending strain) The scratches on the conductor surface are shallow and there is no problem as a product, but there are many pits due to corrosion and the maximum depth of the pits is deep, so the corrosion resistance is poor. This makes it somewhat unsatisfactory as a stranded wire to prevent stress corrosion.

Sample 7 (hard copper wire stranded wire with a wire surface bending strain of 0.16%) The conductor can is shallow and the product is not in the same order, but the number of pits caused by corrosion is significantly smaller than the comparison sample, and the corrosion resistance is improved. has been done. Therefore, this countermeasure sample has sufficient properties as a stress corrosion countermeasure stranded wire.

Sample 8 (hard lead wire twisted I with 0.4% line surface bending strain)
M) The conductor can is shallow and has no problems as a product, has excellent corrosion resistance, and has excellent performance as a stress corrosion countermeasure stranded wire.

Sample 9 (hard copper wire stranded wire with green surface bending strain of 5.7%) Excellent in both conductor and corrosion resistance, and has sufficient performance as a stress ID: 1 corrosion resistant stranded wire.

Sample 10 (measured hard copper m-stranded wire with 6.3% wire surface bending strain) The conductor had deep scratches and was unsatisfactory as a product. In addition, the number of bits due to corrosion was large and the maximum pit depth was deep, so although the corrosion resistance was improved compared to Comparative Sample 2, there were problems. Therefore, this countermeasure sample does not have sufficient performance as a stress corrosion countermeasure 7'g wire.

From the above results, in order to obtain a residual stress-relieving hard copper wire stranded wire with few conductor flaws and excellent corrosion resistance, it is necessary to use the present invention.
．． It can be seen that the treatment should be performed to give a linear surface bending strain of 15% to 6%.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing an example of the residual stress prevention position by rotary surface bending used to carry out the present invention;
The figure is a longitudinal sectional view of the rotating body in FIG. 1. 1. Hard Tsugu i%! 212'l G'...Fixing member 3,
3', 3"...Fixing member 4,4',4"...Bearing hole 6,6'...Rotating body hole

Claims (1)

[Claims] 1. (Rotating a single or stranded copper wire directly or in a covered state while passing through a rotating body whose wire axis center is biased. A method for removing residual stress in a single hard copper wire or a stranded wire, which is characterized by continuously applying plastic strain in the entire radial direction of the hard copper wire by from 0.15%
The method for removing residual stress according to claim 1, wherein the residual stress is 6%.