Aluminum alloy conductor, composite steel-cored aluminum stranded conductor and preparation method thereof

Abstract

The present application relates to a kind of aluminum alloy conductor, composite steel core aluminum stranded conductor and preparation method thereof, it is related to wire and cable technical field.The preparation method of aluminum alloy conductor includes: aluminum alloy rod is according to single pass less than 1.1 The drawing of 12 passes~15 passes is carried out, and the conductor is obtained;The conductor after drawing is heated to 160~170 ℃ and kept for 440~460 min, and then furnace cooling is obtained, to obtain aluminum alloy conductor.The composite steel core aluminum stranded conductor includes: the composite steel core of stranding structure, the aluminum stranded conductor layer of multiple stranding structures is included outside composite steel core;Composite steel core includes galvanized steel wire and the above-mentioned aluminum alloy conductor.Aluminum alloy conductor adopts more pass drawing process and specific heat treatment, has more excellent conductivity, yield strength, elongation and tensile strength.Prepared composite steel core aluminum stranded conductor with it can significantly reduce sag.

Description

Technical Field

[0001] This invention belongs to the field of wire and cable technology, specifically relating to an aluminum alloy conductor, a composite steel-cored aluminum stranded wire, and a method for preparing the same. Background Technology

[0002] Aluminum steel-cored stranded wire (ACSR) is characterized by high mechanical strength and is suitable for long-span transmission. However, when facing ultra-high voltage long-distance transmission, it has disadvantages such as large weight, significant sag, and relatively low conductivity.

[0003] Existing technologies suppress sag by replacing the reinforcing core. For example, carbon fiber composite aluminum stranded wire (ACCC) uses carbon fiber composite material as the core wire, which is lightweight; however, its cost is 6 to 8 times that of galvanized steel core, and the core rod is brittle with weak radial compressive strength, requiring special pulleys for construction, and is prone to breakage under impact, resulting in high maintenance risks. Alternatively, aluminum-clad steel core or Invar core conductors can be used to prepare stranded wire, which works by using their low expansion characteristics to suppress sag; however, the density of aluminum-clad steel is still greater than 6.5 g / cm³. 3 Invar's content is even higher, reaching 8.10 g / cm³. 3 Excessive self-weight is a detrimental factor in suppressing sag, and in addition, Invar steel or cladding technology is expensive, making it difficult to promote in large-scale line projects.

[0004] Therefore, how to improve the wire used in the production of steel-cored aluminum stranded wire, while reducing weight, ensuring strength and maintaining resistivity levels, and without increasing construction difficulty, is a problem that those skilled in the art urgently need to solve when developing steel-cored aluminum stranded wire. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an aluminum alloy conductor, a composite steel-cored aluminum stranded wire, and a method for preparing the same. A special preparation method is used to obtain a high-strength aluminum alloy conductor, and the prepared composite steel-cored aluminum stranded wire has the characteristics of low weight, low sag, and high conductivity.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] In a first aspect, embodiments of the present invention disclose a method for preparing an aluminum alloy conductor, comprising the following steps:

[0008] S1. Pull the aluminum alloy rod 12 to 15 times with a compression ratio of less than 1.1 per pass to obtain the conductor;

[0009] S2. Heat the drawn wire to 160℃~170℃ and hold for 440min~460min, then cool it with the furnace to obtain aluminum alloy wire.

[0010] The aluminum alloy comprises the following components by mass percentage: Si 0.50%~0.85%, Mg 0.60%~0.85%, Fe ≤0.45%, Cu ≤0.10%, Mn ≤0.03%, Cr ≤0.03%, Zn ≤0.08%, Ti ≤0.10%, B ≤0.06%, with other impurities individually ≤0.03% and total ≤0.10%, and the balance being Al.

[0011] Secondly, embodiments of the present invention disclose an aluminum alloy wire, which is prepared by the above-described method for preparing aluminum alloy wires.

[0012] Thirdly, embodiments of the present invention disclose a composite steel-core aluminum stranded wire, comprising a stranded composite steel core, the outer side of which includes a multi-layer stranded aluminum stranded wire layer; the composite steel core comprises galvanized steel wire and the aforementioned aluminum alloy conductor.

[0013] Fourthly, embodiments of the present invention disclose a method for preparing the above-mentioned composite steel-cored aluminum stranded wire, comprising the following steps:

[0014] S3. Stir the galvanized steel wire and the above-mentioned aluminum alloy wire into a composite steel core;

[0015] S4. Strand multiple layers of aluminum stranded wires on the outside of the composite steel core to obtain composite steel core aluminum stranded wire.

[0016] The beneficial effects of this invention are as follows:

[0017] The method for preparing aluminum alloy conductors provided by this invention employs a drawing process with more passes to achieve a refined grain structure. The aluminum alloy conductors obtained after specific heat treatment exhibit superior conductivity, yield strength, elongation, and tensile strength. Compared to conventional aluminum alloy conductors produced using conventional drawing processes or other heat treatment processes, they possess higher strength and better conductivity; furthermore, compared to carbon fiber composite materials, the resulting aluminum alloy conductors exhibit more balanced mechanical properties, significantly reducing construction difficulty.

[0018] The other raw materials for composite steel-cored aluminum stranded wire are galvanized steel wire that has undergone double-stage annealing. Double-stage annealing can more precisely control the microstructure and properties of the material, optimize the mechanical properties of the galvanized steel wire and the quality of the galvanized layer; its mechanical strength is improved together with the strength of the aluminum alloy conductor, which can improve the rated breaking force of the composite steel-cored aluminum stranded wire product; and thanks to the light weight of the aluminum alloy conductor, sag can be significantly reduced; ultimately optimizing the overall performance of the steel stranded wire. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 This is a schematic cross-sectional view of the composite steel-cored aluminum stranded wire prepared in Example 2.

[0021] Figure 2 This is a schematic diagram of the preparation method in Example 2.

[0022] The components include: 1. galvanized steel wire; 2. aluminum alloy conductor; 3. anti-corrosion grease; 4. aluminum stranded wire; 5. rubber scraper; 6. high-precision pressing die; 7. horizontal straightening roller; 8. vertical straightening roller; 9. paper tape; and 10. composite steel core. Detailed Implementation

[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] One or more embodiments of the present invention provide a method for preparing aluminum alloy wires, comprising the following steps:

[0026] S1. Pull the aluminum alloy rod 12 to 15 times with a compression ratio of less than 1.1 per pass to obtain the conductor;

[0027] S2. Heat the drawn wire to 160℃~170℃ and hold for 440min~460min, then cool it with the furnace to obtain aluminum alloy wire.

[0028] The aluminum alloy comprises the following components by mass percentage: Si 0.50%~0.85%, Mg 0.60%~0.85%, Fe ≤0.45%, Cu ≤0.10%, Mn ≤0.03%, Cr ≤0.03%, Zn ≤0.08%, Ti ≤0.10%, B ≤0.06%, and other impurities, each ≤0.03% and the total ≤0.10%, with the balance being Al.

[0029] In the above process, through more drawing processes in S1, the deformation amount in each pass is reasonably distributed, the surface stress concentration is significantly reduced, and the grains are fully broken and refined in multiple continuous deformations. The finer grains result in higher strength in the final product. The wires with finer grains, after heat treatment in S2, produce products with stable conductivity, yield strength, elongation and tensile strength that are higher than those of ordinary aluminum wires of the same specification, which can meet the needs of high-end applications such as precision electronic cables and ultra-fine coaxial cables.

[0030] Optionally, in S1, the drawing temperature is 50℃~55℃, which completely blocks high-temperature oxidation and aluminum chips sticking to the die, improves conductivity and makes the aluminum wire surface mirror-like, and can maintain a wire drawing speed of 600m / min~800m / min without breaking.

[0031] Optionally, in S1, the ratio of the diameter of the alloy rod before drawing to the diameter of the wire after drawing is 2.5~3. In conventional technology, to achieve this effect, the number of drawing passes is usually less than 11. This solution uses more drawing passes, which can achieve more precise dimensional control and significantly reduce the rate of defects such as scratches, pits, and cracks, thereby improving conductivity. It can also significantly improve the service life of the drawing die.

[0032] Optionally, in S2, the heating time to 160℃~170℃ is 50 min~70 min; by using a reasonable heating rate, holding time and furnace cooling process, a product with better conductivity, yield strength, elongation and tensile strength can be obtained.

[0033] One or more embodiments of the present invention provide an aluminum alloy conductor, which is prepared by the above-described method for preparing aluminum alloy conductors; the conductor has a diameter of 3.5±0.01mm, a tensile strength ≥325 MPa, a resistivity at 20℃ ≤32.811 nΩ•m, and an elongation after fracture ≥6%.

[0034] One or more embodiments of the present invention provide a composite steel-cored aluminum stranded wire, comprising a stranded composite steel core, and an outer layer of multi-layer stranded aluminum stranded wire; the composite steel core comprises galvanized steel wire and the aforementioned aluminum alloy conductor.

[0035] In the above structure, galvanized steel wire has high strength and corrosion resistance, while aluminum alloy conductor has high tensile strength and low resistance. The composite steel core formed by twisting the two together with the outer aluminum stranded wire is made into composite steel core aluminum stranded wire, which can reduce sag and improve conductivity while maintaining low self-weight, thus meeting the requirements of long-distance and large-capacity power transmission.

[0036] Optionally, the galvanized steel wire undergoes a two-stage annealing process. The two-stage annealing process includes heating to 300℃~320℃ and holding for 120 min~130 min, then cooling in the furnace and reheating to 300℃~320℃ and holding for 100 min~110 min.

[0037] Optionally, the number of aluminum stranded wire layers includes 2 to 3 layers, and the stranding direction between the layers is opposite.

[0038] Optionally, the composite steel core and the inner aluminum stranded wire layer are filled with anti-corrosion grease to reduce its usage while ensuring anti-corrosion effect and to prevent excess anti-corrosion grease from overflowing into the outer aluminum stranded wire layer and causing contamination.

[0039] The present invention provides one or more embodiments of a method for preparing the above-mentioned composite steel-cored aluminum stranded wire, comprising the following steps:

[0040] S3. Stir the galvanized steel wire and the above-mentioned aluminum alloy wire into a composite steel core;

[0041] S4. Strand multiple layers of aluminum stranded wires on the outside of the composite steel core to obtain composite steel core aluminum stranded wire.

[0042] Optionally, in S3 and S4, anti-corrosion grease is injected simultaneously during the stranding / stranding process. In S4, the anti-corrosion grease on the surface is scraped off before stranding the outermost aluminum stranded layer, and no anti-corrosion grease is injected when stranding the outermost aluminum stranded layer. This concentrates the anti-corrosion grease on the composite steel core and the inner aluminum stranded layer, thereby controlling the amount of anti-corrosion grease used and avoiding contamination of the surface of the composite steel core aluminum stranded wire.

[0043] Optionally, in S3, after the composite steel core is compressed and tightened, it is then straightened; this can constrain the pitch of each layer in real time, eliminate the risk of wire skipping caused by uneven strength, and ensure the high strength and stability of the composite steel core.

[0044] To further understand the effects of the composite steel-cored aluminum stranded wire and its preparation method provided in the embodiments of the present invention, the embodiments of the present invention will be further explained below with reference to specific examples.

[0045] Example 1

[0046] An aluminum alloy wire, the preparation method of which includes:

[0047] S0. Smelt aluminum ingots with a purity ≥ 99.90% to obtain molten aluminum. The mass fraction of each element in the molten aluminum should meet the following requirements: total impurities less than 0.26%, with impurities of Fe < 0.15%, Si < 0.12%, and Cu < 0.01%, the ratio of Fe to Si greater than 1.3, rare earth 0.05%–0.2%, and boron 0.01%–0.08%.

[0048] The mass fractions of each element in the molten aluminum will be adjusted to: Si 0.50%~0.85%, Mg 0.60%~0.85%, Fe ≤0.45%, Cu ≤0.10%, Mn ≤0.03%, Cr ≤0.03%, Zn ≤0.08%, Ti ≤0.10%, B ≤0.06%; among the remaining impurities, each individual impurity ≤0.03% and the total impurity ≤0.10%; the balance is Al; for example, this meets the composition requirements of 6201 aluminum alloy.

[0049] After the molten aluminum is thoroughly degassed and impurities removed in a holding furnace and a nitrogen carrier belt blowing refining device, and then allowed to stand and filter, it is poured into a continuous casting machine ladle through a flow channel. The molten aluminum is continuously cast into billets, which are then hot rolled, straightened online, and sheared to finally obtain φ9.5 mm rods. The properties of the aluminum alloy rods are tested to meet the following requirements: resistivity ≤0.03450, tensile strength 160 MPa ~220 MPa.

[0050] S1. The aluminum alloy rod is drawn using a 13-pass drawing process, with the die compression ratio of each pass being less than 1.1. This ensures that the aluminum alloy rod remains in a uniform, gradual, and controllable plastic deformation state during the step-by-step diameter reduction process, ultimately obtaining a wire with a diameter of 3.5±0.01mm. During the process, the drawing oil temperature is monitored and strictly controlled within 50℃~55℃ to prevent high-temperature oxidation and aluminum chips sticking to the die.

[0051] More passes in the drawing process can effectively improve the diameter control accuracy, achieving a diameter tolerance within ±0.01mm for the conductor. The surface defect rate, such as scratches, pits, and cracks, is reduced to 0.05%, and the surface exhibits a mirror-like finish. The average size of the internal grains is 8μm, and the yield strength is 6.3%, the elongation after fracture is , the tensile strength is 326MPa, and the conductivity is 52.5%IACS.

[0052] Meanwhile, the multi-pass drawing process improves process stability, with the final pass wire output rate reaching 600m / min. The balanced force on the die extends the die change frequency from once every 48 hours to once every 120 hours (extending the lifespan by 2.5 times). The triple monitoring of oil temperature, flow rate, and pressure reduces the failure rate of the lubrication system by 70%, reduces downtime losses by about 220 hours per year, increases unit capacity by 20%, and reduces the overall processing cost per ton of aluminum by 5%, truly achieving a triple breakthrough in high quality, high efficiency, and low cost.

[0053] S2. The drawn wire is heated to 165°C for 60 minutes and held at that temperature for 450 minutes. Then it is cooled in the furnace to obtain aluminum alloy wire. During the process, intermittent circulating ventilation is provided in the furnace of the heat treatment device, and the center of the furnace is left empty without placing any wire reels to ensure that the hot air is circulated throughout the entire area and the temperature field is uniform, thereby ensuring the consistency and stability of the performance of each type of wire.

[0054] After the heat treatment process in S2, the aluminum alloy wire obtained achieves a tensile strength ≥330MPa and a resistivity ≤32.811 nΩ•m at 20 ℃.

[0055] For example, the aluminum alloy wire obtained by using the above steps S0 to S2 is superior to the requirements of LHA1 type aluminum-magnesium-silicon alloy round wire in GB / T 23308-2009.

[0056] Comparative Example 1

[0057] The difference between this comparative example and Example 1 is that the aluminum alloy rod obtained in step S0 of Example 1 is drawn to the same size as that in Example 1 through 10 passes. During the process, the die compression ratio of each pass is adjusted to 1.1~1.5 by adjusting the machine parameters, and the wire drawing temperature is controlled at 50~55℃.

[0058] The diameter tolerance of the conductor was within ±0.03 mm, the surface defect rate such as scratches, pits, and cracks was 0.8%, the average size of the internal grains was 10 μm, the average elongation after fracture was 4.8%, the average tensile strength was 317 MPa, and the conductivity was 52.5% IACS.

[0059] Comparative Example 2

[0060] The difference between this comparative example and Example 1 is that the wire obtained in step S1 of Example 1 is divided into multiple samples, which are subjected to the aging process shown in Table 1, wherein the aging parameters are set by the control variable method.

[0061] The sample was heated to 167°C for 60 minutes and held at that temperature for 360 minutes before being cooled in the furnace. The resulting aluminum alloy wire is Comparative Example 2-1.

[0062] The sample was heated to 170°C for 60 minutes and held at that temperature for 420 minutes before being cooled in the furnace. The resulting aluminum alloy wire is Comparative Example 2-2.

[0063] The sample was heated to 173°C for 60 minutes and held at that temperature for 240 minutes before being cooled in the furnace. The resulting aluminum alloy wire is a comparative example 2-3.

[0064] The sample was heated to 175°C for 60 minutes and held at that temperature for 180 minutes before being cooled in the furnace. The resulting aluminum alloy wire is a comparative example 2-4.

[0065] The properties of each sample were tested, and the results were summarized with those of Example 1, as shown in Table 1. Among them, the results of multiple tests on tensile strength were not less than the values ​​in the table, and the results of multiple tests on resistivity at 20℃ were not greater than the values ​​in the table.

[0066] Table 1. Statistical table of aging treatment process and properties of each sample.

[0067]

[0068] As can be seen from Table 1 above, Example 1 has better overall performance and can achieve higher tensile strength while ensuring resistivity requirements. The composite steel-cored aluminum stranded wire prepared with it has the advantage of lighter weight and effectively reduces the sag of the composite steel-cored aluminum stranded wire product.

[0069] Example 2

[0070] A composite steel-cored aluminum stranded wire, such as Figure 1 As shown, the composite steel core includes a stranded structure, and two stranded aluminum stranded wire layers are wrapped around the outside of the composite steel core. The aluminum stranded wire layers are made of aluminum stranded wire 4. The composite steel core includes galvanized steel wire 1 and aluminum alloy wire 2 obtained in Example 1. The stranding directions of the inner and outer aluminum stranded wire layers are opposite. The composite steel core and the inner aluminum stranded wire layer are filled with anti-corrosion grease 3, while the outermost aluminum stranded wire layer does not contain anti-corrosion grease 3, so as to avoid excess anti-corrosion grease overflowing from the outer aluminum stranded wire layer and causing contamination.

[0071] For example, the aluminum stranded wire 4 is the JL3 type aluminum stranded wire in GB / T 17048-2017, with a size of 42 / 3.5mm; the galvanized steel wire 1 has a size of 9 / 3.5mm, and the composite steel core aluminum stranded wire has a size of 19 / 3.5mm.

[0072] For example, the interlayer distribution of the anti-corrosion grease 3 conforms to Case 2 in Appendix B of GB / T 1179-2017, that is: the composite steel core and the inner aluminum stranded wire layer are filled with anti-corrosion grease, while the outermost aluminum stranded wire layer does not contain anti-corrosion grease.

[0073] Among them, galvanized steel wire 1 undergoes double-stage annealing, specifically: heating to 310℃ and holding for 120 minutes, cooling in the furnace and then reheating to 310℃ and holding for 100 minutes, performing two segmented annealing processes to improve the flexibility and mechanical properties of the galvanized steel wire; the measured tensile strength is 1370MPa and the elongation is 4.6%.

[0074] Preparation methods include:

[0075] S3. The galvanized steel wire and the aluminum alloy wire prepared in Example 1 are stranded into a composite steel core; anti-corrosion grease is injected simultaneously during the stranding process; during the process, such as Figure 2 As shown, after scraping off excess anti-corrosion grease with a rubber scraper 5, a high-precision compression mold 6 is used to compress and tighten the composite steel core 10 in real time to completely eliminate the risk of skipped strands caused by uneven strength. Then, straightening wheels are used for straightening. The straightening wheels include horizontal straightening wheels 7 and vertical straightening wheels 8, which can straighten in multiple directions to ensure that the composite steel core 10 is round and without skipped strands. During the process, paper tape 9 is used to temporarily bind and position the composite steel core every 200 m to ensure that the composite steel core is round and that there are no loose strands. All of these are removed before stranding the multi-layer aluminum stranded wire. Then, the aluminum stranded wire and the composite steel core are stranded together.

[0076] S4. Strand multiple layers of aluminum stranded wires on the outside of the composite steel core, with opposite stranding directions between layers and right-hand direction for the outermost layer, to obtain a composite steel core aluminum stranded wire. Similarly, scrape off the anti-corrosion grease from the surface before stranding the outermost aluminum stranded wire, and do not inject anti-corrosion grease when stranding the outermost aluminum stranded wire, so that the anti-corrosion grease is concentrated in the composite steel core and the inner aluminum stranded wire layers, in order to control the amount of anti-corrosion grease used and avoid causing contamination on the surface of the composite steel core aluminum stranded wire.

[0077] Compared to traditional steel-cored aluminum stranded wire, finished composite steel-cored aluminum stranded wire has the advantages of being lightweight and having high conductivity. Furthermore, the galvanized steel wire has higher mechanical properties, which can significantly enhance the mechanical properties of the composite steel-cored aluminum stranded wire. The measured values ​​are: rated breaking force of 267kN and DC resistance of 0.0643Ω / km. Due to its lighter weight, it can achieve a smaller sag.

[0078] Comparative Example 3

[0079] The difference between this comparative example and Example 2 is that the galvanized steel wire does not undergo double-stage annealing. At this time, the properties of the galvanized steel wire include: tensile strength of 1350MPa and elongation of 3.0%. Using galvanized steel wire that has not undergone double-stage annealing, aluminum alloy wire from Example 1, and composite steel-cored aluminum stranded wire prepared according to the method of Example 2, its rated breaking force is measured to be 260kN and DC resistance is 0.0643Ω / km.

[0080] Since the galvanized steel wire in this comparative example does not undergo double-stage annealing, its mechanical properties are lower than those of the galvanized steel wire in Example 2, which has undergone double-stage annealing. This is reflected in the performance of the composite steel-cored aluminum stranded wire product, which shows a lower rated breaking force.

[0081] Comparative Example 4

[0082] The difference between this comparative example and Example 2 is that the aluminum alloy wire prepared in Example 1 is not used. Instead, the wire prepared in Comparative Example 1 is used as the raw material to prepare composite steel core aluminum stranded wire according to the method of Example 2. The rated breaking force is measured to be 254kN and the DC resistance is 0.0643Ω / km.

[0083] Because the aluminum alloy conductor in this comparative example has fewer drawing passes, its surface defects, internal grain size, and mechanical properties are all lower than those of the aluminum alloy conductor in Example 2. This is reflected in the performance of the composite steel-cored aluminum stranded wire product, which is characterized by a lower rated breaking force.

[0084] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing an aluminum alloy conductor, characterized in that, Includes the following steps: S1. The aluminum alloy rod is drawn 12 to 15 times with a compression ratio of less than 1.1 per pass to obtain a wire; the drawing temperature is 50 to 55℃; the drawing speed is 600 m / min to 800 m / min. S2. Heat the drawn wire to 160℃~170℃ and hold for 440min~460min, then cool it with the furnace to obtain aluminum alloy wire. The aluminum alloy comprises the following components by mass percentage: Si 0.50%~0.85%, Mg 0.60%~0.85%, Fe ≤0.45%, Cu ≤0.10%, Mn ≤0.03%, Cr ≤0.03%, Zn ≤0.08%, Ti ≤0.10%, B ≤0.06%, and other impurities, each ≤0.03% and the total ≤0.10%, with the balance being Al.

2. The method for preparing aluminum alloy wires as described in claim 1, characterized in that, In S1, the ratio of the diameter of the aluminum alloy rod before drawing to the diameter of the aluminum alloy wire after drawing is 2.5 to 3.

3. The method for preparing aluminum alloy wires as described in claim 1, characterized in that, In S2, the heating time is 50 min to 70 min.

4. An aluminum alloy conductor, characterized in that, It is prepared by the method for preparing aluminum alloy wires as described in any one of claims 1-3.

5. A composite steel-cored aluminum stranded wire, characterized in that, The composite steel core includes a stranded structure, and the outer side of the composite steel core includes a multi-layer stranded aluminum wire layer; the composite steel core includes galvanized steel wire and aluminum alloy conductor as described in claim 4.

6. The composite steel-cored aluminum stranded wire as described in claim 5, characterized in that, The galvanized steel wire undergoes a two-stage annealing process, which includes heating to 300℃~320℃ and holding for 120 min~130 min, then cooling in the furnace and reheating to 300℃~320℃ and holding for 100 min~110 min.

7. The composite steel-cored aluminum stranded wire as described in claim 5, characterized in that, The number of aluminum stranded wire layers includes 2 to 3 layers, and the stranding directions between the layers are opposite.

8. The composite steel-cored aluminum stranded wire as described in claim 5, characterized in that, The composite steel core and the inner aluminum stranded wire layer are filled with anti-corrosion grease.

9. A method for preparing a composite steel-cored aluminum stranded wire as described in any one of claims 5-8, characterized in that, Includes the following steps: S3. Stir galvanized steel wire and aluminum alloy wire together to form a composite steel core; S4. Strand multiple layers of aluminum stranded wires on the outside of the composite steel core to obtain the composite steel core aluminum stranded wire.

10. The method for preparing composite steel-cored aluminum stranded wire as described in claim 9, characterized in that, In S3 and S4, anti-corrosion grease is injected simultaneously during the stranding / stranding process. In S4, the anti-corrosion grease on the surface is scraped off before stranding the outermost aluminum strand, and no anti-corrosion grease is injected when stranding the outermost aluminum strand. In S3, after the composite steel core is compressed and tightened, it is then straightened.

Images