JP2005032572A - Method of preventing corrosion of aluminum cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of preventing corrosion of an aluminum cable which is used in the atmosphere or in a tunnel, exhibits superior durability, even if exposed to rainwater or leakage water in the tunnel or the like, and can be used maintenance-freely over a long period of time. <P>SOLUTION: In the method of preventing corrosion of the aluminum cable, corrosion-preventive metal fittings comprising a metal electrochemically baser than an aluminum material forming the aluminum cable are installed between support points to support this aluminum cable as sacrificial anodes, in the aluminum cable using the aluminum material comprising an aluminum or aluminum alloy. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for preventing corrosion of various aluminum cables manufactured using an aluminum material made of aluminum or an aluminum alloy, and in particular, one or more of an aluminum element wire, an aluminum stranded wire, an aluminum coating material, and the like. The present invention relates to an anticorrosion method for aluminum cables such as overhead power transmission lines, railway feeders, optical fiber composite overhead ground lines, and overhead distribution lines (distribution lines).

  Overhead power transmission lines and railway feeders installed between steel towers are required to be lightweight in order to reduce the construction cost of steel towers and other equipment, and the central tensile strength consisting of steel cores and carbon fiber assemblies Steel core aluminum stranded wire formed by twisting aluminum strands around the body, aluminum coated invar core special heat resistant aluminum alloy stranded wire that was developed for the purpose of increasing capacity, etc. (See JP-A-07-254,309, JP-A-07-272,538, JP-A-2001-23,436, JP-A-2001-76,538, JP-A-2001-291,429, and JP-A-2002-338,981), and A pipe-shaped aluminum covering material (see JP-A-07-220,537, JP-A-08-47,150 and JP-A-2001-291,429) that accommodates and protects an optical fiber cable for an optical fiber composite ground wire It is used.

  In such an aluminum cable, various countermeasures against corrosion have been taken conventionally. For example, a method of making the aluminum wire itself a material having excellent corrosion resistance (see JP-A-2001-23,436). , A method of filling a resin-based watertight mixture in a gap between wires (see JP 2001-76,538 A), a synthetic resin material between a steel stranded wire and a surrounding conductive wire twisted layer, etc. A method of interposing a hardly corrosive member (see Japanese Patent Application Laid-Open No. 07-272,538), a method of interposing, filling or applying an anticorrosive grease (Japanese Patent Application Laid-Open No. 08-47,150, Japanese Patent Application Laid-Open No. 2001-291,429) 2002-338,981 reference), a method of encapsulating at least a steel stranded wire with a non-corrosive metal tube made of a low electrode potential metal material that can be a sacrificial anode with respect to a steel material (see Japanese Patent Laid-Open No. 07-254,309), Lower melting point than this protective pipe on the surface of pipe-like aluminum coating material A method of providing a zinc or anticorrosion layer consisting of an alloy having a corrosion prevention effect (see JP-A-07-220,537) it has been proposed.

  By the way, in such an aluminum cable, it is inevitable that corrosive substances such as chloride ions and sulfate ions that affect the function of the aluminum material adhere to the surface, and in the case of an overhead power transmission line, for example. Normally, the distance between the transmission towers is wide, and the central part of the wire hangs down in an arc, and the attached electrolyte accumulates near the lowermost part of the arc (the bottom of the arc), causing corrosion and cannot withstand its own weight. There is a risk of breaking. In addition, in the case of railway feeders, a large amount of copper powder, etc. generated by sliding between a train pantograph and copper conductors floats in the air and then accumulates on the wires, causing rainfall and in tunnels. This copper powder accumulates on the bottom of the arc that hangs down due to water leakage or the like, and corrosion proceeds due to electrochemical action, which may eventually be damaged.

  In addition, although any of the above-described methods performs the anticorrosion treatment over the entire length of the aluminum cable, corrosion progresses intensively at the arc bottom of the above-described aluminum cable, even if the total length of the aluminum cable is increased. Even if the anticorrosion treatment is applied over the entire length, the life of the aluminum cable itself is determined by the progress of the corrosion at the bottom of the arc.

Japanese Patent Laid-Open No. 07-220,537 Japanese Unexamined Patent Publication No. 07-254,309 JP 07-272,538 A Japanese Patent Laid-Open No. 08-47,150 JP 2001-23,436 Japanese Patent Laid-Open No. 2001-76,538 Japanese Patent Laid-Open No. 2001-291,429 JP 2002-338,981 A

  Therefore, as a result of intensive studies on a method for performing corrosion-free maintenance-free over a long period of time for various aluminum cables using an aluminum material, the present inventor has found this between support points that support the aluminum cable. Corrosive substances such as chloride ions and sulfate ions adhere to the bottom of the arc that hangs down under its own weight, along with rainwater, etc. by attaching a metal that is more electrochemically lower than the aluminum material forming the aluminum cable as a sacrificial anode. The present invention has been completed by finding that maintenance of the cable made of aluminum can be prevented over a long period of time until the sacrificial anode disappears due to corrosion even if an environment that is easy to perform is generated.

  Accordingly, the object of the present invention is to provide an anticorrosion for an aluminum cable that can be used in the atmosphere or in a tunnel, exhibits excellent durability even when exposed to rainwater, water leakage in a tunnel, etc., and can be used maintenance-free for a long time. It is to provide a method.

  That is, according to the present invention, an aluminum cable using an aluminum material made of aluminum or an aluminum alloy is electrochemically less basic than an aluminum material forming an aluminum cable between support points for supporting the aluminum cable. This is an aluminum cable anticorrosion method in which a metal anticorrosion fitting is attached as a sacrificial anode.

  In the present invention, as an aluminum cable, for example, an overhead power transmission line formed using one or more selected from an aluminum element wire formed from an aluminum material, an aluminum stranded wire, and an aluminum coating material, Examples include railway feeders, optical fiber composite overhead ground wires, overhead distribution lines (distribution lines), etc., and these are various methods, for example, a method of making the aluminum strand itself a material with excellent corrosion resistance. , A method of filling a resin-based water-tight mixture in a gap between wires, a method of interposing a hardly corrosive member such as a synthetic resin material between a steel stranded wire and a surrounding conductive wire twisted layer, anticorrosion A method of interposing, filling, or applying grease, a method of encapsulating at least a steel stranded wire with a non-corrosive metal tube made of a low electrode potential metal material that can be a sacrificial anode for the steel material, a pipe-like aluminum coating material On the surface of By a method such as providing a zinc or anticorrosion layer consisting of an alloy having a corrosion protection than protective pipe a low melting point, it may be one which is previously anticorrosion treatment.

  Further, in the present invention, the anti-corrosion metal fitting provided as a sacrificial anode between the support points for supporting the aluminum cable may be formed of an electrochemically base metal than the aluminum material forming the aluminum cable. It can be appropriately selected depending on the type of aluminum material, and specific examples include one or more metals selected from zinc, magnesium, aluminum, and alloys thereof.

  When selecting the metal for forming the anti-corrosion metal fitting, it is preferable to select a base metal that is preferably 30 mV or more, more preferably 50 mV or more from the natural potential of the aluminum cable in rainwater or condensed water. If the metal is 30 mV or more lower than the natural potential in the rainwater or condensed water, excellent anticorrosion performance can be exhibited even in a corrosive environment exposed to rainwater or water leakage in the tunnel.

  Further, the anti-corrosion metal fitting is preferably composed of a plurality of covering members each having a covering portion divided into a plurality of portions and a flange portion for connecting the covering portions to each other. It is good to be designed so that it can be detachably attached to cover the circumference. If this anti-corrosion metal fitting is detachably attached to the aluminum cable, when the anti-corrosion metal fitting is worn out and its function as a sacrificial anode deteriorates, the anti-corrosion metal fitting can be easily replaced to provide excellent anti-corrosion performance again. It can be demonstrated.

  According to the method of the present invention, it is used in the atmosphere or in a tunnel, and even when exposed to rainwater, water leakage in the tunnel, etc., excellent corrosion resistance is exhibited, and as a result, excellent durability is exhibited, Aluminum cables can be used maintenance-free for a long time.

  Hereinafter, preferred embodiments of the present invention will be specifically described based on examples shown in the accompanying drawings.

  1-3, the corrosion prevention method of the power transmission line 1 which concerns on an example of implementation of this invention is shown. The power transmission line 1 used here is a steel core aluminum stranded wire formed by twisting aluminum strands around a steel core, and is installed between steel towers (not shown) via a suspension insulator 2 and is aerial. They are used as power transmission lines and railway feeders.

  In this embodiment, between the suspension insulators 2 (that is, between the steel towers), the central portion of the transmission line 1 hangs down in an arc shape, and a corrosion prevention as a sacrificial anode near the lowermost portion (arc bottom portion) hangs down in the arc shape. A metal fitting 3 is attached.

  As shown in FIG. 2 and FIG. 3 in an enlarged manner, the anti-corrosion metal fitting 3 includes a covering portion 4a, 4b divided into two and a flange portion 5a for connecting the covering portions 4a, 4b to each other. , 5b and is arranged so as to surround the outer circumference of the electric wire in a cylindrical shape at the arc bottom of the transmission line 1, and between the flanges 5a, 5b a bolt 6a And a nut 6b. The fastening member 6 is detachably attached.

  The metal fittings 3a and 3b constituting the anticorrosion metal fitting 3 are 30 mV or more, preferably 50 mV, more than the natural potential of the steel core aluminum stranded wire in water when the transmission line 1 is exposed to rainwater or water leakage in the tunnel. It is preferable that the base metal is formed as described above, and that the covering portions 4a and 4b and the flange portions 5a and 5b constituting the metal fittings 3a and 3b are all formed of a metal serving as a sacrificial anode. In addition, when a resin-based water-tight mixture is filled in the gaps between the wires, a non-corrosive member such as a synthetic resin is interposed between the copper stranded wire and the surrounding conductive twisted layer. If the transmission line is insulated, such as when organic insulation such as a method of interposing, filling, or applying anti-corrosion grease is present, insulation treatment of the transmission line Remove the part and make sufficient electrical contact with the anti-corrosion bracket. Good.

  Here, the progress of corrosion of the power transmission line 1 formed of an aluminum material depends on the wet time on the surface and the amount of adhesion of corrosive substances such as sea salt particles and sulfate radicals. And the attached anti-corrosion metal fitting 3 suppresses corrosion of the power transmission line 1 main body by corroding and depleting as a sacrificial anode in these metal corrosive environments. Moreover, the copper powder produced by the sliding of the copper overhead wire and the pantograph on the train track that most adversely affects the corrosion of the transmission line 1 accumulates on the transmission line 1 and accumulates on the bottom of the arc due to rainwater or water leakage. Then, a local battery is formed between the copper powder and the power transmission line 1, and the power transmission line 1 begins to corrode from the outer peripheral portion. Since the accumulation of copper powder selectively occurs on the metal surface having a large potential difference, the copper powder selectively concentrates on the surface of the anticorrosion metal fitting 3 having a lower electric potential than that of the transmission line 1. If the electric potential of the electric wire 1 is more than 30 mV, the anti-corrosion metal fitting 3 that does not impair the conductivity at the copper powder concentrated portion serves as a cover against the corrosive environment, and contributes to the improvement of the corrosion resistance of the transmission line 1.

[Test Examples 1-6 and Comparative Test Examples 1-3]
Hereinafter, based on the test example and comparative test example which concern on the Example of this invention, this invention is demonstrated more concretely.
An aluminum stranded wire having a diameter of 22 mmφ × 500 mm formed by twisting 36 99.7% aluminum strands (1070 Al) having a diameter of 3.2 mmφ was used as a test object.
Further, by using an aluminum material shown in Table 1 and sand mold casting, the same shape as shown in FIG. 2 and FIG. 3 of the above Example 1 and having a thickness of 10 mm × 200 mm in length is provided (two pieces). The structure was made up of split metal fittings) and used as test pieces for anticorrosion metal fittings.

Measure the natural potential in the 5wt% -NaCl aqueous solution of the above-mentioned aluminum stranded wire specimen and the corrosion-proof metal specimen, and determine the 5wt% -NaCl potential difference between the aluminum stranded wire and the anti-corrosion metal fitting. (MV) was determined.
In addition, both ends of the aluminum stranded wire are fixed using A1070WY welding wire so that the central portion hangs down in a gentle arc shape, and the test piece of the anticorrosion fitting is stranded by using galvanized steel bolts and nuts. Fastened to the center of the wire (the bottom of the arc), assuming that electrolyte retention and copper deposition will occur on the aluminum twisted wire, perform the CASS test (JIS Z 2371) for 1000 hours, and the anti-corrosion metal fitting and this anti-corrosion From the contact surface of the aluminum stranded wire to which the metal fittings are attached and the anticorrosion situation around the connection part, ◎: All are healthy including the lower part of the anticorrosion metal fitting and the periphery of the connection part. However, corrosion resistance was evaluated in three stages: corrosion wear was large, x: copper powder adhered to the periphery of the connection between the corrosion protection metal and the aluminum stranded wire, and corrosion occurred.
The results are shown in Table 1.

  As is apparent from the results shown in Table 1, a test example in which the anticorrosion metal fitting according to the present invention was mounted even under severe accelerated corrosion test conditions such as a CASS test having a large amount of copper ions and chlorine ions and low pH. In Nos. 1 to 6, metal copper deposition was not confirmed at the lower part of the aluminum stranded wire and around the anticorrosion metal, and no corrosion was observed. Of these, the corrosion progresses on the surface of the anticorrosion metal fittings were relatively slight in the aluminum alloy-based test examples 1 to 3, and in the test examples 4 to 6, the aluminum anticorrosion effect was sufficient for the aluminum stranded wire. The wear on the bracket surface was slightly large.

  On the other hand, in Comparative Test Examples 1 to 3, since the potential difference between the aluminum stranded wire and the anticorrosion metal fitting is small, there is much copper precipitation at the anticorrosion metal interface, and the erosion on the bottom surface is large. . However, erosion tended to be small in the part where the anti-corrosion metal fittings covered the aluminum stranded wire surface.

  According to the anticorrosion method of the present invention, it is possible to give excellent corrosion resistance to an aluminum cable simply by attaching an anticorrosion metal fitting as a sacrificial anode to an aluminum cable manufactured using an aluminum material. As a result, the aluminum cable Can be used maintenance-free over a long period of time.

It is explanatory drawing which shows notionally the state to which the anticorrosion method which concerns on Example 1 of this invention was applied. It is an expansion front explanatory drawing which shows the corrosion-proof metal fitting of FIG. It is an expansion side explanatory view showing the corrosion-proof metal fitting of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Power transmission line, 2 ... Suspension insulator 3 ... Anticorrosion metal fitting, 3a, 3b ... Metal fitting member, 4a, 4b ... Covering part, 5a, 5b ... Flange part, 6a ... Bolt, 6b ... Nut.

Claims (5)

  For aluminum cables using aluminum materials made of aluminum or aluminum alloys, anti-corrosion metal fittings made of metal that is more electrochemically base than the aluminum materials forming the aluminum cables are provided between the support points that support the aluminum cables. An anticorrosion method for an aluminum cable, characterized by being attached as a sacrificial anode.   The aluminum cable according to claim 1, wherein the aluminum cable is formed using one or more selected from an aluminum strand formed of an aluminum material, an aluminum stranded wire, and an aluminum coating material. Anticorrosion method.   The method for preventing corrosion of an aluminum cable according to claim 1 or 2, wherein the metal forming the anticorrosion metal fitting is one or more metals selected from zinc, magnesium, aluminum, and alloys thereof.   The method for preventing corrosion of an aluminum cable according to any one of claims 1 to 3, wherein the metal forming the anticorrosion metal fitting is a base metal that is at least 30 mV from the natural potential of the aluminum cable in water.   The anti-corrosion metal fitting is composed of a plurality of metal fitting members each having a covering portion divided into a plurality of portions and a flange portion for connecting the covering portions to each other, and covers the entire outer periphery of the aluminum cable at a predetermined position. The method for preventing corrosion of an aluminum cable according to any one of claims 1 to 4, wherein the method is detachably attached to the cable.

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