JPH02132710A - Manufacture of composite wire having irregular section - Google Patents

Abstract

PURPOSE:To improve the hardness of a protruding part for preventing deposition of snow to an overhead earth-wire by setting the degression ratio of the protruding part smaller than the degression ratio of the other parts of aluminum or aluminum alloy coating material. CONSTITUTION:A composite wire 1 is obtained by applying a coating material having a protruding part 5 around a core material of a steel wire, the composite wire 1 is drawn at a degression ratio of 2-20%. The coating material consisting of aluminum or aluminum alloy is hardened by this process, so it becomes less likely to be deformed or have flaws if any external force is applied. The degression ratio of the protruding part 5 is set smaller than the degression ratio of the other parts of the coating material. Occurrence of burning during a drawing process is restricted by this, and the core material of the steel wire is also hardened by the process, thereby the strength is increased for the whole composite wire.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Fields of Application] The present invention is applicable to an aluminum coated steel wire with protrusions used in the production of an optical fiber composite overhead ground wire (OPGW), etc.
The present invention relates to a method of manufacturing a composite wire having an irregular cross section.

[Prior Art] An optical fiber composite overhead ground wire is made by combining a composite metal wire 1 with a protrusion having a cross-sectional shape shown in FIG. 1(a) or (b) and a composite metal wire 2 without a protrusion into a They are manufactured by arranging them on the circumference as shown in the figure and further twisting them together. Note that FIG. 2 is an example in which the composite metal wire 1 with protrusions shown in FIG. 1(b) is incorporated. The composite metal wire 1 with protrusions may have, for example, a circular cross section [FIG. 1(a)] or a flat cross section [FIG. 1(a)].
The steel wire 3 shown in Figure (b) is used as a core material, and aluminum is extruded around the core material and coated with aluminum. The composite metal wire 1 made of the aluminum sheathing material 4 and the steel wire 3 has a cross section curved in an arc shape, and the aluminum sheathing material 4 is locally curved on the surface with the longer arc length (large arc surface). Composite metal wire 1 protruding from
A protrusion 5 extending in the longitudinal direction is formed. This one composite metal wire 1 with a protrusion and five composite metal wires 2 which are similar to the composite metal wire 1 except that they do not have a protrusion are connected to a second composite metal wire 1.
As shown in the figure, they are connected in the width direction to form a cylindrical shape. Then, the optical fiber unit is inserted into the central space 6 surrounded by the metal wires 1 and 2, and
Twist each metal wire 1 and 2 together. As a result, the protrusion 5
An optical fiber composite overhead ground wire with spirally arranged optical fibers is obtained. This protrusion 5 has a function of preventing snow from accumulating on the overhead ground wire.

However, the protrusion 5 of the composite metal wire 1 described above is
Since the aluminum coating material 4 is formed by extruding aluminum around the periphery, the temperature of the aluminum coating material 4 reaches 400 to 500° C. during this extrusion process, resulting in a problem that the coating material 4 becomes soft. Therefore, when an optical fiber composite overhead ground wire is manufactured by twisting the extruded coated metal wire 1 together with the metal wire 2,
There is a drawback that the protrusion 5 may be deformed by external force or may be scratched. Furthermore, there is also the problem that the protrusion 5 is easily deformed or scratched in the overhead line work for connecting this optical fiber composite overhead ground wire. Conventionally, the composite metal wire 1 is made by extruding and covering the steel wire 3 with a covering material 4 having protrusions 5, and then drawing the entire wire uniformly and work-hardening the protrusions 5. Manufactured.

[Problems to be Solved by the Invention] However, the method of work-hardening the protrusions 5 by uniformly drawing the entire composite metal wire 1 after extruding and coating the composite metal wire 1 having the protrusions 5 does not There were problems such as burn-in on the die during the wire processing process, which caused wire breakage.

The present invention has been made in view of such problems, and includes:
Even if an external force is applied to the projections of the sheathing material during the wire twisting process or overhead wire work, the projections can be prevented from deforming or getting scratches without causing problems such as burn-in and disconnection. An object of the present invention is to provide a method for manufacturing a composite wire having an irregularly shaped cross section.

[Means for Solving the Problems] The method for manufacturing a composite wire having an irregular cross section according to the present invention involves coating a steel wire core material with an aluminum or aluminum alloy covering material having a protrusion, thereby producing a composite wire. and a step of drawing this composite wire at an area reduction rate of 2 to 20%, and in the wire drawing process, the area reduction rate of the protrusion is equal to that of other parts of the covering material. It is characterized by a smaller area reduction rate.

[Function] In the present invention, after a composite wire is obtained by coating a steel wire core material with a covering material having a protrusion, the composite wire is
Wire drawing is performed with a reduction rate of 0%. As a result, the covering material made of aluminum or aluminum alloy undergoes work hardening and becomes hard, making it difficult to deform or get scratches even when subjected to external forces. Furthermore, since the area reduction rate of the protrusion is smaller than the area reduction rate of other parts of the covering material, occurrence of seizure during wire drawing as in conventional methods is suppressed. Furthermore, the steel wire core material also undergoes work hardening, increasing the strength of the entire composite wire.

[Example code] Examples of the present invention will be described below.

In this embodiment, first, as in the case shown in FIGS. 1(a) and 1(b), aluminum is extruded around the steel wire 3 having a circular cross section or an arcuate cross section. An aluminum covering material 4 having protrusions 5 is coated. The composite wire obtained by this extrusion process has a cross-sectional shape that is almost similar to the cross-sectional shape of the desired composite wire product with protrusions, but the cross-sectional area of the wire drawing process in the subsequent process is smaller than that of this product shape. It is necessary to make the shape larger to compensate for the decrease.

Next, use a drawing die to draw this composite line into 2 to 2
Wire drawing is performed at a liquid level ratio of 0%. In this case, the cross-sectional reduction rate of the protrusion 5 is made smaller than the cross-sectional reduction rate of the covering material 4 other than the protrusion 5. As a result, the cross-sectional areas of the aluminum covering material 4 and the core steel wire 3 are reduced, and a composite wire 1 with protrusions having a predetermined product shape and dimensions as shown in FIG. 1 is manufactured. Then, the aluminum covering material 4 undergoes work hardening due to wire drawing, and the hardness of the covering material 4 including the projections 5 increases.

This prevents the protrusion 5 from being deformed or damaged even if an external force is inadvertently applied to the protrusion 5 during the wire twisting process during manufacturing of the optical fiber composite overhead ground wire or during the overhead line work of the optical fiber composite overhead ground wire. adhesion is suppressed. In addition, since the core steel wire 1 has also undergone work hardening, the composite wire 1
also increases its overall strength.

In this case, if the area reduction rate in the wire drawing step is less than 2%, the degree of workability will be too small and the covering material 4 will not be sufficiently work hardened. Furthermore, when a composite wire having a complicated cross-sectional shape as shown in FIG. Wire drawing becomes impossible due to seizure.

For this reason, the overall area reduction rate in wire drawing is 2.
It is necessary to set the cross-sectional area ratio to 20% to 20%.

On the other hand, according to the manufacturing test results of the present inventors, the protrusion 5
When the area reduction rate of the coating material 4 was smaller than that of the portions other than the projections 5, seizure during wire drawing was less likely to occur. Therefore, the area reduction rate in the protrusion 5 is smaller than in other parts. so that

Furthermore, in wire drawing, a lubricant is usually supplied between the die and the aluminum material. In this case, it is preferable to use a dry lubricant for wire drawing containing calcium stearate as a main component than to use a wet lubricant for wire drawing such as mineral oil in terms of preventing seizure.

Next, the change in hardness of the aluminum covering material 4 before and after wire drawing when the composite wire 1 with protrusions is wire drawn with an area reduction rate of 3% by the method of the above-described example will be shown.

Table 1 Hardness of this aluminum coating material 4 Bickers Hv;
The load (50 g) was measured at five measurement points.

As shown in Table 1, the maximum hardness of the covering material 4 before wire drawing was 27.8, while the maximum hardness of the covering material 4 after wire drawing was 42.8. 6, and the lowest value is 37.4, which is an extremely high value. As described above, this embodiment has a remarkable effect on improving the hardness of the protrusion.

[Effects of the Invention] According to the present invention, after a steel wire is coated with an aluminum or aluminum alloy coating material, the wire is drawn so that the area reduction rate of the protrusion is smaller than the area reduction rate of other parts. Unlike conventional methods, the coating material is work-hardened without burning or breaking during the wire drawing process, and even if an external force is inadvertently applied to the protrusion during the wire twisting process or overhead wire work, the protrusion remains intact. Deformation and adhesion of scratches are suppressed.

In this way, since the hardness is increased by work hardening, pure aluminum, which is inherently soft but has excellent corrosion resistance and electrical conductivity, can also be used as the covering material.

Therefore, according to the present invention, the corrosion resistance and conductivity of the optical fiber composite overhead ground wire can be easily improved.

Furthermore, in addition to the hardening of the coating material, the core steel wire is also subjected to work hardening, which increases the strength of the entire composite wire.

Furthermore, since the protrusions of the composite wire are formed using a die, the dimensional accuracy of the product is high.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the cross-sectional structure of a composite wire with protrusions, and FIG. 2 is a cross-sectional view showing the composite wire assembled into an optical fiber composite overhead ground wire.

Claims (1)

[Claims] (1) The process includes a step of coating a steel wire core material with aluminum or an aluminum alloy to obtain a composite wire having protrusions, and a step of drawing this composite wire at an area reduction rate of 2 to 20%. A method for manufacturing a composite wire having an irregular cross section, characterized in that in the wire drawing process, the area reduction rate of the protrusion is smaller than the area reduction rate of other parts of the aluminum or aluminum alloy covering material. (2) The method for manufacturing a composite wire having an irregular cross section according to claim 1, wherein a solid lubricant is used in the wire drawing step.