Overhead conductor for coastal region and preparation method thereof

Abstract

The invention discloses an overhead conductor for a coastal region and a preparation method thereof, and belongs to the field of wire and cable manufacturing, the overhead conductor comprises a composite steel core and an aluminum alloy stranded wire stranded on the composite steel core, the composite steel core comprises a steel inner core and a coating layer, the coating layer comprises an aluminum alloy layer and a nickel-containing low-aluminum layer, and the aluminum alloy layer is a nickel-containing low-aluminum layer. The nickel-containing low-aluminum layer is coated outside the steel inner core, and the aluminum alloy layer is coated outside the nickel-containing low-aluminum layer, so that a gradient structure of the steel inner core / the nickel-containing low-aluminum layer / the aluminum alloy layer / the aluminum alloy stranded wire is formed. The method is particularly suitable for coastal areas.

Description

Technical Field

[0001] This invention relates to the field of wire and cable manufacturing, and in particular to an overhead conductor for coastal areas and its preparation method. Background Technology

[0002] Currently, the conductors used in my country's overhead power transmission lines are still mostly traditional steel-cored aluminum stranded wire. To prevent steel corrosion, a layer of zinc is usually hot-dip galvanized on the surface of the steel core. The manufacturing process of steel-cored aluminum stranded wire involves stranding pre-treated aluminum wires onto a pre-treated hot-dip galvanized steel core. The aluminum wires can be multiple strands and stranded in one or two layers on the surface of the steel core.

[0003] With the development of modern technology, higher and higher requirements have been placed on overhead conductors. Traditional steel-cored aluminum stranded wire can no longer meet the needs of modern technology in terms of power transmission capacity, weather resistance and other aspects, and there is an urgent need to improve the technology of overhead conductors.

[0004] In technological improvements, there have been instances of overhead conductors using aluminum alloy conductors to replace aluminum wires, but there is still no inner core suitable for coastal environments that can be used with aluminum alloy stranded wires.

[0005] The above background information is provided to facilitate understanding of the present invention and is not intended to be publicly known technology disclosed to the general public prior to the application of this invention. Summary of the Invention

[0006] In view of the above-mentioned defects, the present invention provides a solution that aims to improve at least one of the problems mentioned in the background art.

[0007] The technical solution is: an overhead conductor for coastal areas, comprising a composite steel core and aluminum alloy stranded wire stranded on the composite steel core. The composite steel core includes a steel inner core and a cladding layer. The cladding layer includes an aluminum alloy layer and a nickel-containing low-aluminum layer. The nickel-containing low-aluminum layer covers the outside of the steel inner core, and the aluminum alloy layer covers the outside of the nickel-containing low-aluminum layer, forming a gradient structure of steel inner core / nickel-containing low-aluminum layer / aluminum alloy layer / aluminum alloy stranded wire.

[0008] Furthermore, the steel inner core is a steel rod.

[0009] Furthermore, the steel bar is made of 304 stainless steel and has a diameter of 2.5 mm.

[0010] Furthermore, the thickness of the nickel-containing low-aluminum layer is 25μm~35μm, the thickness of the aluminum alloy layer is 55μm~65μm, and the sum of the thickness of the nickel-containing low-aluminum layer and the thickness of the aluminum alloy layer is 80μm~100μm.

[0011] Furthermore, the nickel-containing low-aluminum layer has a thickness of 30 μm, and the aluminum alloy layer has a thickness of 60 μm.

[0012] The present invention also provides a method for preparing overhead conductors for use in coastal areas.

[0013] The technical solution is: a method for preparing overhead conductors for coastal areas, comprising the following steps: S1, Preparing the composite steel core, including the following steps: S11, take the steel bar, and pre-treat and dry the steel bar to 100℃~200℃; S12, the steel bar is placed in a hot-dip galvanizing bath and hot-dipped twice. The first hot-dip solution is a nickel-containing low-aluminum melt with a composition of 70% Ni, 15%~25% Al, and 5%~15% Si. The hot-dip temperature is controlled at 950℃~1050℃, and the target coating thickness is 25μm~35μm. The second hot-dip solution is an aluminum alloy melt with the same composition as the aluminum alloy monofilament. The hot-dip temperature is controlled at 690℃~720℃, and the target coating thickness is 55μm~65μm. S13, Remove the hot-dip steel strip and perform post-processing; S2, take an aluminum alloy monofilament; S3 involves twisting aluminum alloy monofilaments onto a composite steel core.

[0014] Furthermore, the diameter of the aluminum alloy monofilament is 2.5 mm, and the composition of the aluminum alloy monofilament or aluminum alloy melt is: Fe 8.5%, V 1.3%, Si 1.7%, with the balance being Al.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention first increases the aluminum area by replacing zinc with aluminum in hot dipping. Then, it replaces the aluminum melt with a molten aluminum alloy of the same composition as the stranded wire in hot dipping. Next, with the same total hot-dip layer thickness, it hot-dip dips in a nickel-containing low-aluminum molten liquid before hot dipping the aluminum alloy.

[0016] When the steel rod with a nickel-containing low-aluminum inner layer and an aluminum alloy outer layer is used in conjunction with aluminum alloy stranded wire as an overhead conductor, a gradient structure of iron (steel inner core) / nickel-containing low-aluminum / aluminum alloy / aluminum alloy stranded wire is formed. This combination of steel core and aluminum alloy stranded wire achieves unexpected results in salt spray treatment, making it particularly suitable for coastal areas. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the cross-section of the overhead conductor of the present invention; In the diagram, 1 is a composite steel core, and 2 is an aluminum alloy stranded wire. Detailed Implementation

[0018] As used in this article: "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of this application. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0021] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0022] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (K is any number representing a multiplier). It is important to understand that, unlike the number of parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0023] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0024] In this invention, the neutral salt spray test method is as follows: Test temperature: 35℃±2℃ 80 cm 2 Average settlement rate of horizontal area: 1.5 ml / h ± 0.5 ml / h Concentration of sodium chloride solution (collected solution): 50 g / L ± 5 g / L pH value (collected solution): 6.5~7.2 (25℃±2℃) Spray pressure: 98 kPa Saturated tower hot water temperature: 48℃ Test cycle: 720h In this invention, the transmission capacity is calculated based on the current carrying capacity value detected by the DL / T1935-2018 Overhead Conductor Current Carrying Capacity Test Method.

[0025] Comparative Example 1 Please refer to Figure 1 , Figure 1 This is a schematic diagram of the cross-section of the overhead conductor of the present invention.

[0026] An overhead conductor for coastal areas includes a composite steel core 1 and an aluminum alloy stranded wire 2 stranded on the composite steel core 1. This overhead conductor for coastal areas is manufactured through the following steps: S1, Preparing composite steel core 1 includes the following steps: S11. Take a 304 stainless steel bar with a diameter of 2.5mm (hereinafter referred to as the steel bar), and pre-treat and dry the steel bar to about 150℃.

[0027] S12, the steel bar is placed into the immersion bath for hot immersion. The hot immersion liquid is molten aluminum with an aluminum content of ≥99.8%. The hot immersion temperature is controlled at around 700℃, and the target coating thickness is 90μm.

[0028] S13, Remove the steel bar with aluminum layer after hot-dip immersion and perform post-processing.

[0029] S2, take an aluminum alloy monofilament with a diameter of 2.5mm and a composition of Fe 8.5%, V 1.3%, Si 1.7%, with the balance being Al.

[0030] S3, aluminum alloy monofilaments are twisted onto a composite steel core 1 formed by steel rods with aluminum layers, and aluminum alloy monofilaments are twisted together to form aluminum alloy stranded wire 2.

[0031] The products in this embodiment were subjected to current carrying capacity tests and neutral salt spray tests, and the results are shown in Table 1 below.

[0032] Comparative Example 2 Compared with Comparative Example 1, the difference is that in S12, the hot-dip liquid is aluminum alloy melt, and the composition content of the aluminum alloy melt is the same as that of the aluminum alloy monofilament.

[0033] The products in this embodiment were subjected to current carrying capacity tests and neutral salt spray tests, and the results are shown in Table 1 below.

[0034] Comparative Example 3 Compared with Comparative Example 1, the difference is that in S12, the hot-dip liquid is a nickel-containing low-aluminum melt with a composition of 70% Ni, 20% Al, and 10% Si, and the hot-dip temperature is controlled at around 700℃.

[0035] The products in this embodiment were subjected to current carrying capacity tests and neutral salt spray tests, and the results are shown in Table 1 below.

[0036] Example 1 Compared to Comparative Example 3, the difference lies in the following: In S12, the hot dipping process is performed twice. The first hot dipping solution is a nickel-containing low-aluminum melt with a composition of 70% Ni, 20% Al, and 10% Si. The hot dipping temperature is controlled at approximately 1000℃, and the target coating thickness is 30μm. The second hot dipping solution is an aluminum alloy melt with the same composition as the aluminum alloy monofilament. The hot dipping temperature is controlled at approximately 700℃, and the target coating thickness is 60μm.

[0037] The products in this embodiment were subjected to current carrying capacity tests and neutral salt spray tests, and the results are shown in Table 1 below.

[0038] Example 2 Compared with Example 1, the difference is that in S12, the composition of the nickel-containing low-aluminum melt is 70% Ni, 22% Al, and 8% Si.

[0039] The products in this embodiment were subjected to current carrying capacity tests and neutral salt spray tests, and the results are shown in Table 1 below.

[0040] Example 3 Compared with Example 1, the difference is that in S12, the composition of the nickel-containing low-aluminum melt is 70% Ni, 18% Al, and 12% Si.

[0041] The products in this embodiment were subjected to current carrying capacity tests and neutral salt spray tests, and the results are shown in Table 1 below.

[0042] Comparative Example 4 Compared with Comparative Example 1, the difference is that in S12, the hot-dip solution is zinc melt, the zinc content in the zinc melt is ≥99.95%, and the hot-dip temperature is controlled at around 450℃.

[0043] The products in this comparative example were subjected to current carrying capacity tests and neutral salt spray tests, and the results are shown in Table 1 below.

[0044] Table 1 Remark: In Table 1, the test sample has 7 steel rods and 45 aluminum alloy monofilaments. Of the 7 steel rods, one is in the center and the other six are arranged around it, covering it. The 45 aluminum alloy monofilaments are twisted in two layers on the steel rod group formed by the 7 steel rods, with a filling rate of 92%.

[0045] In Table 1, the transmission capacity ratio is based on the transmission capacity value of Comparative Example 4. The transmission capacity ratio is the ratio of the transmission capacity value of the other embodiments divided by the transmission capacity value of Comparative Example 4. The salt spray test ratio is based on the corrosion area of ​​Comparative Example 4. The salt spray test ratio is the ratio of the corrosion area of ​​the other embodiments divided by the corrosion area of ​​Comparative Example 4.

[0046] As can be seen from Table 1, compared with the existing galvanized core aluminum alloy stranded wire (Comparative Example 4), the neutral salt spray effect of each system of the present invention is better than that of the existing system while maintaining at least the transmission capacity. Among them, Example 2 has the best adaptability, and the system of Example 2 achieves the best match between aluminum alloy stranded wire and stainless steel core.

Claims

1. An overhead conductor for coastal areas, comprising a composite steel core and aluminum alloy stranded wires stranded on the composite steel core, wherein the composite steel core comprises a steel inner core and a cladding layer, characterized in that, The cladding layer includes an aluminum alloy layer and a nickel-containing low-aluminum layer. The nickel-containing low-aluminum layer covers the outside of the steel core, and the aluminum alloy layer covers the outside of the nickel-containing low-aluminum layer, forming a gradient structure of steel core / nickel-containing low-aluminum layer / aluminum alloy layer / aluminum alloy stranded wire.

2. The overhead power line for coastal areas according to claim 1, characterized in that, The steel inner core is a steel rod.

3. The overhead power line for coastal areas according to claim 2, characterized in that, The steel bar is made of 304 stainless steel and has a diameter of 2.5 mm.

4. The overhead power line for coastal areas according to claim 1, characterized in that, The thickness of the nickel-containing low-aluminum layer is 25μm~35μm, the thickness of the aluminum alloy layer is 55μm~65μm, and the sum of the thickness of the nickel-containing low-aluminum layer and the thickness of the aluminum alloy layer is 80μm~100μm.

5. The overhead power line for coastal areas according to claim 1, characterized in that, The nickel-containing low-aluminum layer has a thickness of 30 μm, and the aluminum alloy layer has a thickness of 60 μm.

6. A method for preparing overhead conductors for use in coastal areas, characterized in that, Includes the following steps: S1, Preparing the composite steel core, including the following steps: S11, take the steel bar, and pre-treat and dry the steel bar to 100℃~200℃; S12, the steel bar is placed in a hot-dip galvanizing bath and hot-dipped twice. The first hot-dip solution is a nickel-containing low-aluminum melt with a composition of 70% Ni, 15%~25% Al, and 5%~15% Si. The hot-dip temperature is controlled at 950℃~1050℃, and the target coating thickness is 25μm~35μm. The second hot-dip solution is an aluminum alloy melt with the same composition as the aluminum alloy monofilament. The hot-dip temperature is controlled at 690℃~720℃, and the target coating thickness is 55μm~65μm. S13, Remove the hot-dip steel strip and perform post-processing; S2, take an aluminum alloy monofilament; S3 involves twisting aluminum alloy monofilaments onto a composite steel core.

7. The method for preparing overhead conductors for coastal areas according to claim 6, characterized in that, The aluminum alloy monofilament has a diameter of 2.5 mm, and the composition of the aluminum alloy monofilament or aluminum alloy melt is: Fe 8.5%, V 1.3%, Si 1.7%, with the balance being Al.

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