JPH0448514A - Manufacture of decentering metal composite wire - Google Patents

Abstract

PURPOSE:To easily form a decentering metal composite wire fit for thuderbolt-proof strand by continuously and tubularly molding a metal band having uneven thickness in the width direction while arranging a core material inside this tube and mutually connecting end parts in the width direction of aforesaid metal band. CONSTITUTION:A core material 1 having an almost trapezoidal section and a metal band 2 having a flat upper surface and a saliently swollen under face are prepared. The surfaces of these core material 1 and metal band 2 are sufficiently grinded previously by a brush or blast to prevent foreign matters from being mixed into the interface both of them. Next, by passing the metal band 2 between a plurality of sets of molding rolls to tubularly mold around the core material 1. Next, at a point of time where both ends of the metal band 2 are almost in contact with each other, these both end parts are welded. Thereby, a decentering metal composite wire, where the core material 1 is covered with a coating material 3, can be obtained. The decentering metal composite wire manufactured according to this embodiment is not subjected to wire drawing processing so that bonding strength of the core material 1 and the coating material 3 is relatively low, however, having sufficient bonding strength as a thunderbolt-proof strand.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing an eccentric metal composite wire suitable for lightning-resistant wire used to prevent disconnection accidents of overhead ground wires due to lightning strikes.

[Prior Art] A metal composite wire in which the periphery of a metal wire is coated with a coating material of a different metal has conventionally been manufactured by the method described below.

First, a flat metal band, which will be a covering material, is formed into a circular tube shape around a metal wire, which will be a core material. Thereafter, both ends of this metal strip in the width direction are brought together and then welded to obtain a composite wire.

Next, this composite wire is subjected to a wire drawing process to firmly bond the core material and the covering material to each other.

In the metal composite wire manufactured in this manner, the core material is covered with a coating material having a uniform thickness.

Incidentally, recently, in order to prevent the overhead ground wire etc. from being disconnected due to lightning strikes, it has been carried out to make the overhead ground wire etc. lightning resistant by arranging lightning resistant wires around the overhead ground wire etc.

FIG. 5 is a cross-sectional view showing a conventional optical fiber overhead ground wire (OPGW) equipped with lightning-resistant wires.

An optical fiber cable 21 made up of a plurality of optical fibers is placed inside an aluminum tube 22.
Multiple tubes (six tubes in the figure) are placed around this aluminum tube 22.
Lightning resistant wires 23 are arranged in a twisted manner. The lightning-proof wire 23 is a metal composite wire in which a core material 24 made of steel wire is coated with an aluminum coating material 25 .

When a lightning strike occurs in an overhead ground wire configured in this way, the sheathing material 25 of the lightning-resistant wire 3 melts preferentially, so that the overhead ground wire can be prevented from breaking, and the lightning-resistant wire 23 can be prevented from breaking. Melting of the core material 24 can also be prevented, and breakage of the lightning-proof wire 23 can also be avoided.

[Problems to be Solved by the Invention] However, since the aluminum coating material 25 of the conventional lightning-resistant wire 23 is thin, good lightning-proofing effects can be obtained when the lightning energy is relatively small, but winter lightning with high energy In areas where lightning strikes occur frequently, lightning resistance is insufficient, and wire breakage accidents often occur due to melting and damage during lightning strikes.

On the other hand, in order to improve lightning resistance, it is conceivable to increase the thickness of the aluminum sheathing material 25 of the lightning-resistant element wire 23, but this would result in an increase in the outer diameter of the stranded wire (overhead ground wire) and a decrease in strength. There is a problem. Also, Jikaisho GO-13
As shown in 6423, it is also possible to wrap a metal strip such as aluminum around the stranded wire so as to cover the entire outer circumference of the stranded wire, but this also increases the outer diameter of the stranded wire and increases the weight. There is a problem with that.

The present invention has been made in view of such problems, and includes:
It is an object of the present invention to provide a method for producing an eccentric metal composite wire that can produce an eccentric gold rIt composite wire that has sufficient strength and is suitable as a lightning-resistant wire without increasing weight.

[Means for Solving the Problems] A method for manufacturing an eccentric metal composite wire according to the present invention includes a forming step of forming a metal band having an uneven thickness in the width direction into a tubular shape around a core material, and a forming step of forming a metal band having an uneven thickness in the width direction into a tube shape, It is characterized by having a joining step of joining both ends in the width direction to each other.

[Operations] The inventors of the present invention have conducted various experimental studies in order to obtain a metal composite wire that is lightweight and has sufficient strength as a lightning-resistant wire. As a result, for the lightning-resistant wire, which is placed as the outer layer of the stranded wire that receives lightning strikes, the thickness of the coating layer on the center side of the stranded wire is thinner, and the thickness of the coating material on the outer part, which is more likely to receive energy from lightning strikes, is thicker. It has been found that by using eccentric metal composite wires, the lightning resistance of stranded wires can be significantly improved. This eccentric metal composite wire is, for example, an aluminum or aluminum alloy coated steel wire in which a core material made of steel is eccentrically arranged in a covering material made of aluminum or aluminum alloy.

In this eccentric metal composite wire, when it is twisted around an optical fiber, etc., the coating material on the central part side where the optical fiber etc. is arranged is formed thinly, and the coating material on the outer part, that is, the part where the wave sounds, is thin. Since it is formed thickly and the latent heat of fusion of aluminum in this thick inner portion is large, it is possible to suppress the temperature rise of the core material, and it is possible to prevent the core material from melting due to arc heat during a lightning strike.

In addition, by eccentrically arranging the core material, the inner thickness of the sheathing material is formed, so that the cross-sectional area ratio of the core material can be increased and sufficient strength can be obtained as a lightning-resistant wire. can.

However, when manufacturing such an eccentric metal composite wire, in the method for manufacturing the metal composite wire described above, the relatively soft coating material around the core material is preferentially deformed by the wire drawing process, resulting in uniform deformation. Since the thickness tends to increase, it is impossible to manufacture an eccentric metal composite wire suitable as a lightning-resistant wire.

Therefore, in the present invention, a metal strip having a non-uniform thickness in the width direction is formed into a tube shape, and a core material is placed inside the tube. Then, the widthwise ends of the metal strips are joined by welding or the like. As a result, an eccentric gold fjj4 composite wire that can be used as a lightning-resistant wire is obtained.

In this case, by performing the forming process of forming the metal strip into a tubular shape and the bonding process in an atmosphere of non-oxidizing gas such as an inert gas or reducing gas, surface oxidation of the core material and the coating material can be prevented, and both The bond between the two can be strengthened. For this reason, it is preferable that the forming step of forming the metal strip into a tubular shape and the bonding step are performed in an atmosphere of a non-oxidizing gas such as an inert gas or a reducing gas.

When the eccentric metal composite wire manufactured in this way is subjected to heat and pressure treatment using heated rolls, the constituent components of the core material and sheathing material mutually diffuse, improving the bonding strength between the two. do. For this reason, it is preferable to subject the eccentric metal composite material produced as described above to heating and pressure treatment using heated rolls. Moreover, in this case, the bonding strength between the core material and the covering material can be further improved by supplying electricity to the core material and causing the core material to generate resistance heat.

Note that in order to improve the bonding strength between the core material and the covering material, wire drawing may be performed instead of the pressure treatment using the rolls described above. However, in this case, Figure 4 (
As shown in a), when wire drawing is performed on an eccentric rod consisting of a core material 11 and a covering material 12, the core material 11 shifts from a predetermined position as shown in FIG. 4(b). Therefore, it is difficult to obtain a desired eccentric metal composite. In particular, when the covering material 12 is made of soft metal such as aluminum,
Displacement of the core material 11 due to the wire drawing process occurs significantly.

Therefore, in order to improve the bonding strength between the core material and the covering material, it is preferable to heat and pressurize the composite wire using heated rolls as described above.

[Embodiments] Next, embodiments of the present invention will be described with reference to the accompanying drawings.

FIGS. 1(a) to 1(C) are cross-sectional views showing a method for manufacturing an eccentric metal composite wire according to a first embodiment of the present invention in order of steps.

First, as shown in FIG. 1(a), a core material 1 having a substantially trapezoidal cross section and a metal band 2 having a flat upper surface and a convex lower surface are prepared. The surfaces of the core material 1 and the metal band 2 are sufficiently polished by a brush or blast to prevent foreign matter from entering the interface between the two.

Next, as shown in FIG. 1(b), the metal strip 2 is formed into a tubular shape around the core material 1 by passing between a plurality of sets of forming rolls.

Next, as shown in FIG. 1(C), when both ends of the metal strip 2 are substantially in contact with each other, these ends are welded. As a result, an eccentric metal composite wire in which the core material 1 is covered with the covering material 3 is obtained.

Since the eccentric metal composite wire manufactured according to this example is not wire-drawn, the bonding strength between the core material 1 and the sheathing material 3 is relatively low, but it has sufficient bonding strength as a lightning-resistant wire. .

FIG. 2 is a schematic diagram showing a second embodiment method of the present invention. First, in the same manner as in the first embodiment, the metal strip 2 is passed between a plurality of sets of forming rolls 4 to form a core. The metal strip 2 is formed into a tubular shape around the material, and then both ends of the metal strip 2 in the width direction are welded together using a welding machine 5 to obtain a composite wire.

Next, this composite wire is subjected to a pressure treatment at a pressure of, for example, 1000 atmospheres or more using a pair of rotating pressure rolls 6 having a caliber shaped like the cross-sectional shape of the composite wire. At this time, the composite wire is also subjected to heat treatment by heating the roll 6. The heating temperature of the composite wire at this time is
For example, when the core material is steel and the covering material is aluminum, the temperature is 400 to 500°C. This promotes mutual diffusion of the constituent components of the core material and the covering material, and improves the bonding strength between the two.

In this embodiment, since the composite wire is heated and pressurized by the rotating pressure roll 6, the bonding strength between the core material and the covering material is improved compared to the first embodiment. In addition,
By appropriately selecting the number of stages of the rotating pressure roll 6 and the area reduction rate per pass, the bonding strength between the core material and the covering material can be set to a desired strength. In this case, the area reduction rate per pass of the pressure roll 6 varies depending on the materials of the core material and the covering material, but is suitably about 0 to 5%. For example, when the core material is steel and the covering material is aluminum, the area reduction rate per pass is approximately 2%.

Furthermore, if heating from the pressure roll 6 alone is not sufficient to bond the core material and the covering material, the core material may be electrically energized to cause the core material to generate resistance heat. Further, the composite wire may be subjected to pressure treatment while being heated by electromagnetic induction or gas heating. Furthermore, during heating, there is a possibility that the core material or the covering material may be oxidized due to the oxygen trapped between the core material and the covering material. In order to prevent this oxidation, the forming roll 4 and the welding machine 5 are installed in a chamber 7, and the inside of the chamber 7 is made into an atmosphere of a reducing gas such as H2 and CO or an inert gas such as ml and Ar. Alternatively, it is preferable that the coating material be formed into a tubular shape and welded in an inert gas atmosphere. - For boat fishing, the bonding strength between the core material and the sheathing material is higher when forming and welding is performed in a reducing gas atmosphere than when forming and welding is performed in an inert gas atmosphere. . but,
For example, since some materials, such as Ti, easily absorb HQ and become brittle, it is necessary to select appropriate reducing gases and inert gases depending on the materials of the core material and coating material.

Next, the results of actually manufacturing an eccentric metal composite wire using the method of this embodiment and investigating its characteristics will be described.

An eccentric metal composite wire was manufactured using a steel wire as a core material and an aluminum metal strip having a non-uniform thickness in the width direction as a covering material. Then, this composite wire was subjected to pressure treatment using a pair of rolls at a roll area reduction rate shown in Table 1 below. The temperature of the roll, the temperature of the core material, and the molding atmosphere at this time are also shown in Table 1. In this way, the eccentric metal composite wire shown in FIG. 3 was manufactured. That is,
The diameter d of the core material 1 of these eccentric metal composite wires is 31, and the thickness d2 of the thinnest part of the sheathing material 3 is 0.4-
The thickness d3 of the thickest part is 1.2 mm.

The crushing characteristics of these eccentric metal composite wires were investigated. That is, a test piece having a length of 30 mm was cut from each composite wire, and this test piece was pressurized from the diametrical direction, and the pressure at the time when separation between the core material and the covering material occurred was examined. The results are also shown in Table 1.

Table 1 As is clear from Table 1, forming and welding is performed in a reducing gas atmosphere or inert gas atmosphere, and then pressure treatment is applied to the composite wire while heating the roll and core wire. As a result, the core wire and the covering material are firmly bonded.

[Effects of the Invention] As explained above, according to the present invention, a metal strip having an uneven thickness in the width direction is continuously formed into a tubular shape, and
Since the core material is arranged inside the tube and the ends of the metal strips in the width direction are joined to each other, it is possible to easily form an eccentric metal composite wire suitable as a lightning-proof wire. Further, by subjecting this eccentric gold 8 composite wire to pressure treatment and heat treatment, it is also possible to improve the bonding strength between the core material and the covering material.

[Brief explanation of drawings]

1(a) to 1(C) are cross-sectional views showing the manufacturing method of the eccentric metal composite wire according to the first embodiment of the present invention in the order of steps;
The figure is a schematic diagram showing the second embodiment method of the present invention, FIG. 3 is a sectional view showing an eccentric metal composite wire manufactured by the second embodiment method, and FIGS. 4(a) and (b) are cores. FIG. 5 is a cross-sectional view showing disadvantages when the bonding strength between the material and the covering material is improved by wire drawing, and FIG. 5 is a cross-sectional view showing an 0PGW equipped with a conventional lightning-resistant wire. 1.11.24; Core material, 2; Metal band, 3.12°25;
Covering material, 4; Forming roll, 5; Welding machine, 6; Pressure roll, 7; Chamber, 21; Optical fiber cable, 22
;Aluminum tube, 23;Lightning resistant wire (a) Fig. 2 Fig. 3 (CI) (b) Fig. 4

Claims (4)

[Claims] (1) It is characterized by having a forming step of forming a metal strip having an uneven thickness in the width direction into a tubular shape around a core material, and a joining step of joining both ends of the metal strip in the width direction to each other. A method for manufacturing an eccentric metal composite wire. (2) The method for manufacturing an eccentric metal composite wire according to claim 1, wherein the forming step and the joining step are performed in a non-oxidizing gas atmosphere. (3) The method for manufacturing an eccentric metal composite wire according to claim 1 or 2, further comprising a heating and pressing step of heating and pressing the composite wire obtained in the joining step with a heating roll. (4) The method for manufacturing an eccentric metal composite wire according to claim 3, wherein the heating and pressing step is performed while the core material is being electrically energized to generate resistance heat.