Aluminum-clad invar core heat-resistant aluminum alloy shaped-wire stranded conductor and preparation method therefor

Abstract

An aluminum-clad invar core heat-resistant aluminum alloy shaped-wire stranded conductor, comprising a central core, a steel-aluminum mixed stranded layer concentrically stranded around the central core, a wrapping layer concentrically wrapped around the steel-aluminum mixed stranded layer, and a shaped-wire stranded layer concentrically stranded around the wrapping layer, wherein the central core is made of aluminum-clad invar wires; the steel-aluminum mixed stranded layer comprises several aluminum-clad invar wires and several heat-resistant aluminum alloy round wires, the several aluminum-clad invar wires not being in contact with each other; the wrapping layer is made of a hollow semi-conductive tape; and the shaped-wire stranded layer is made of several heat-resistant aluminum alloy shaped wires. By means of improvements to the composition of a heat-resistant aluminum alloy material, rolling and heat treatment processes, a shaped-wire surface treatment process and a conductor stranding process, the electrical conductivity of heat-resistant aluminum alloy wires is increased to 62.2％ IACS or more, and the tensile strength thereof is increased to 202 MPa or more. Therefore, the aluminum-clad invar core heat-resistant aluminum alloy shaped-wire stranded conductor has excellent electrical conductivity, tensile strength, heat resistance and damping properties.

Description

Aluminum clad steel core heat-resistant aluminum alloy type line strand and preparation method thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of power transmission, in particular to an aluminum clad steel core heat-resistant aluminum alloy type line strand and a preparation method thereof. BACKGROUND

[0002] With the rapid development of economic construction, the demand for electricity is increasing year by year, and the power load is also increasing. In particular, in the case of hot and continuous high temperature, due to the excessive load of the power grid, power limiting measures have to be taken. In economically developed areas, the line corridor is very tight, and it is very difficult to build and expand the line corridor. Therefore, under the existing power transmission corridor conditions, it is an urgent need for the power grid to increase the line transmission capacity and ensure the safe and efficient operation of the power grid. Based on the current situation of the transmission corridor in developed areas, as well as the constraints of investment cost and construction time, the aluminum clad steel core heat-resistant aluminum alloy strand is often used as a product solution. Such conductors have the advantages of high heat-resistant temperature, large transmission capacity margin, low sag, etc., and have the effect of "same diameter, same arc, double capacity", which can fully utilize the path and tower resources of the original line, save space and land resources, and increase the transmission capacity by more than one time by replacing the power transmission conductor, which can ensure the safe transmission of electricity during the power peak period.

[0003] However, the existing aluminum clad steel core heat-resistant aluminum alloy strand uses heat-resistant aluminum alloy material with a conductivity of 60% IACS, which is 1% IACS lower than that of ordinary steel core aluminum strand, and has poor conductivity and high transmission line loss. The tensile strength of the heat-resistant aluminum alloy material is only 159 MPa, and the comprehensive load-bearing performance of the conductor is poor, so it is not easy to be used in line construction in areas with large span, high drop, icing, etc. For long-distance power transmission across provinces and regions, the ordinary structure of the aluminum clad steel core heat-resistant aluminum alloy strand has poor self-damping performance, and long-term micro-wind vibration can easily lead to fatigue breakage of the heat-resistant aluminum alloy wire in the conductor.

[0004] SUMMARY

[0005] The technical problem to be solved by the present application is to provide an aluminum clad steel core heat-resistant aluminum alloy type line strand and a preparation method thereof, which solves the problems of poor conductivity, large transmission line loss, poor comprehensive load-bearing performance, and easy fatigue breakage of the aluminum clad steel core heat-resistant aluminum alloy strand in the prior art.

[0006] In order to solve the above technical problems, the present application provides an aluminum clad steel core heat-resistant aluminum alloy type line strand in the first aspect, which comprises a center line core, a steel-aluminum mixed strand layer concentrically stranded on the center line core, a wrapping layer concentrically wrapped outside the steel-aluminum mixed strand layer, and a type line strand layer concentrically stranded outside the wrapping layer.

[0007] The center line core is an aluminum clad steel wire.

[0008] The steel-aluminum stranded layer comprises a plurality of aluminum-clad mild steel wires and a plurality of heat-resistant aluminum alloy round wires, and the plurality of aluminum-clad mild steel wires are not in contact with each other;

[0009] The wrapping layer is a hollow semi-conductive belt;

[0010] The profiled wire stranded layer is a plurality of heat-resistant aluminum alloy profiled wires;

[0011] The heat-resistant aluminum alloy round wires and the heat-resistant aluminum alloy profiled wires have an electrical conductivity of ≥62.2% IACS, a tensile strength of ≥202 MPa, and a heat resistance of ≥96% at 280°C for 1 hour.

[0012] Compared with the heat-resistant aluminum alloy round wire with an electrical conductivity of 60% IACS used in the aluminum-clad mild steel core heat-resistant aluminum alloy stranded wire in the prior art, the heat-resistant aluminum alloy round wire and the heat-resistant aluminum alloy profiled wire used in the aluminum-clad mild steel core heat-resistant aluminum alloy profiled wire of the present application have an electrical conductivity of ≥62.2% IACS, which is increased by more than 2.2% IACS. In a heavy load operation state, the power transmission line loss can be reduced by more than 3.5%. At the same time, the tensile strength of the heat-resistant aluminum alloy round wire and the heat-resistant aluminum alloy profiled wire is increased from 159 MPa in the prior art to more than 202 MPa. In the case of the same specification, the rated breaking force of the aluminum-clad mild steel core heat-resistant aluminum alloy profiled wire is increased by more than 10% compared with the aluminum-clad mild steel core heat-resistant aluminum alloy stranded wire in the prior art, the tensile weight ratio of the stranded wire is increased, the conductor sag is reduced, and the ultimate ice thickness is increased by more than 6 mm.

[0013] The wrapping layer is provided, and the hollow semi-conductive belt of the wrapping layer can buffer and reduce the vibration energy transmission between the outer heat-resistant aluminum alloy profiled wire stranded layer and the adjacent inner steel-aluminum stranded layer, thereby improving the self-damping performance of the conductor.

[0014] Further, the steel-aluminum stranded layer is one or more layers, and the aluminum-clad mild steel wires and the heat-resistant aluminum alloy round wires in each layer are uniformly distributed. The aluminum-clad mild steel wires in each layer and between the layers are not in contact with each other. Due to the different inherent vibration frequencies of the heat-resistant aluminum alloy round wires and the aluminum-clad mild steel wires, when wind vibration occurs, the two types of wire strands in the same layer interfere with each other, thereby reducing the vibration energy.

[0015] Further, the thickness of the wrapping layer is 0.35-0.45 mm, and preferably 0.4±0.02 mm.

[0016] Further, the cross section of the heat-resistant aluminum alloy profiled wire is "convex", and the convex angle θ 凸角 = θ 圆心角 / 5. The two sides of the heat-resistant aluminum alloy profiled wire are roughened surfaces. When adjacent heat-resistant aluminum alloy profiled wire strands vibrate, they rub against each other and consume vibration energy, thereby further improving the self-damping performance of the conductor.

[0017] Further, the preparation method of the heat-resistant aluminum alloy round wire or heat-resistant aluminum alloy profile is:

[0018] (1) obtaining an aluminum alloy rod by continuous casting and rolling, the continuous rolling passes through a 4-pass two-roller mill and an 8-pass three-roller mill;

[0019] The mass percentage of each component in the aluminum alloy rod is: Si 0.08-0.12wt%, Fe 0.08-0.14wt%, Zr 0.45-0.60wt%, Ni 0.05-0.1wt%, RE 0.4-0.5wt%, wherein RE is: Ce, Er and Nd in a mass ratio of 3:4:3, the sum of Cr, Mn, V, Ti is less than 0.004wt%, and the rest is Al and unavoidable impurities;

[0020] (2) heat treating the aluminum alloy rod;

[0021] (3) drawing the heat-treated aluminum alloy rod to obtain a heat-resistant aluminum alloy round wire or heat-resistant aluminum alloy profile.

[0022] The present application adds Ni element in the heat-resistant aluminum alloy to form NiAl3 phase, significantly improving the tensile strength and heat resistance; adds Er, Ce and Nd elements, the purpose is to form Al3(Er / Ce / Nd) phase, which is precipitated after heat treatment and pinned in the grain boundary, improving the heat resistance and electrical conductivity of the alloy material.

[0023] Further, in step (1), the process of continuous casting and rolling is:

[0024] a. high-purity aluminum ingots with a purity of 99.90% or higher are melted, initially 2kg of AlB3 per ton of aluminum water is added to the furnace for boronization, then AlB3 is slowly added according to the actual content of B, V and Ti elements, gradually reducing to completely eliminate the content of V and Ti elements, reducing their impact on the electrical conductivity of the metal material, while controlling B≤0.002wt%;

[0025] b. once the slag is removed, then use a sodium particle refining agent and argon for primary refining, stand for 15-20min, then perform secondary slag removal, and stand for another 30-50min; wherein the primary refining temperature is 780-800℃;

[0026] The sodium particle refining agent is in the form of particles, which can prolong the reaction time in the aluminum water, has good degassing and impurity removal effect, and also has the effect of removing sodium. Sodium element is easy to form low-melting-point compounds, which can easily produce organizational defects in the subsequent annealing process, affecting the electrical conductivity of the metal material, and the addition of the sodium particle refining agent can well ensure the electrical conductivity of the material;

[0027] c. Add aluminum-boron master alloy (AlB3), aluminum-silicon master alloy (AlSi60), iron agent (75Fe), aluminum-zirconium master alloy (AlZr15), aluminum-nickel master alloy (AlNi10), aluminum-cerium master alloy (AlCe10), aluminum-erbium master alloy (AlEr5), and aluminum-neodymium master alloy (AlNd30) to alloy the aluminum liquid, so that the chemical composition in the aluminum liquid finally reaches the specified ratio range;

[0028] d. Blow in sodium-removing granular refining agent again, and perform secondary refining with argon gas. Let it stand for 15-20 minutes and then remove the slag. During the secondary refining, after blowing in the sodium-removing refining agent, the furnace is sealed again for 15-20 minutes to allow the granular refining agent to fully react with the impurities in the aluminum liquid. The secondary refining temperature is 720-740℃.

[0029] Secondary refining can remove impurities generated during the alloying process, while lowering the refining temperature, reducing hydrogen absorption in the molten aluminum, and further purifying the molten aluminum.

[0030] e. The molten aluminum is poured out and then degassed and filtered in a degassing box and a filter box;

[0031] f. Continuous casting is carried out, wherein the casting temperature is 680-700℃, the casting speed is 5.0-6.0t / h, the cooling water temperature is 20-25℃, and the billet temperature is 450-470℃. The supersaturated phase is obtained through high temperature and rapid cooling to improve the electrical properties.

[0032] g. Rolling is carried out to obtain a high-conductivity, ultra-heat-resistant aluminum alloy rod, wherein the initial rolling temperature is 400-450℃ and the final rolling temperature is 50-150℃.

[0033] Furthermore, in step (3), the diameter of the aluminum alloy rod is 13.6±0.5mm, the wire drawing adopts a 9-13 pass wire drawing die, and the tensile coefficient of the wire drawing die is 1.255-1.305.

[0034] This invention, through statistical analysis of a large amount of wire drawing data, concludes that the die elongation coefficient (elongation coefficient = cross-sectional area S of the rod without die drawing) during the wire drawing process of heat-treated heat-resistant aluminum alloy rods 前 ÷ Cross-sectional area S of the rod after being drawn by the die 后 When the tensile strength is around 1.28, the effects of each mold on the mechanical and electrical properties of the heat-resistant aluminum alloy rod are as follows: the average increase in tensile strength is 2.142%; the average increase in resistivity is 0.074%.

[0035] Under existing continuous casting and rolling conditions, the tensile strength of heat-resistant aluminum alloy rods after heat treatment is 144.5 MPa, and the tensile strength of drawn single wires is only 170 MPa, which obviously cannot meet the requirement of ≥202 MPa. This invention designs the rolling process with a configuration of a 4-pass two-roll mill and an 8-pass three-roll mill. The diameter of the heat-resistant aluminum alloy rod obtained after rolling reaches 13.60 mm. When the tensile strength of the heat-resistant aluminum alloy rod after heat treatment reaches 160.0 MPa or higher, it is drawn into a 3.50 mm diameter heat-resistant aluminum alloy wire using 11 drawing dies. By increasing the amount of cold deformation during the drawing process, the tensile strength of the heat-resistant aluminum alloy wire is increased to 202 MPa or higher.

[0036] Further, in step (2), the heat treatment is as follows: heating to 343±3℃ and holding for 72±2h, then air-cooling to room temperature for first-level heat treatment; heating to 262±2℃ and holding for 33±1h, then air-cooling to room temperature for second-level heat treatment; heating to 166±1℃ and holding for 19±0.5h, then air-cooling to room temperature for third-level heat treatment. To obtain a heat-resistant aluminum alloy rod with 62.7% IACS high conductivity, if the "I" or "II" heat treatment technology is applied, a high-temperature heat treatment process above 400℃ is required. Considering the material's sensitivity to high temperatures, long-term high-temperature heat treatment will greatly reduce the rod's strength. Although the conductivity requirement can be met, the rod's strength will be reduced to below 152MPa, indirectly causing the single-wire strength to fail to reach 202MPa. This invention employs a three-stage heat treatment process, in which the temperature and time of each stage of heat treatment are reduced. As the resistivity decreases stepwise, the low-temperature treatment and staged cooling back to room temperature ensure that the strength of the rod remains within a reasonable range with only a slight decrease, ensuring that the strength after heat treatment reaches 160.0 MPa or above.

[0037] Furthermore, when drawing convex heat-resistant aluminum alloy profiles, a convex cross-section die is used, with the central angle θ of the die being... 圆心角 = 360° / n, where n is the number of single lines in the current layer, and convex angle θ 凸角 =θ 圆心角 / 5, the radius R of the transition angle of the arc surface is 0.70±0.05mm, and the inner hole shape of the first wire drawing die to the last wire drawing die gradually changes from a circle to a "convex" cross section to avoid large deformation causing the single wire to break.

[0038] Furthermore, the heat-resistant aluminum alloy profile is roughened on both sides using a drawing die with raised threads on the inner surface to perform single-die drawing, achieving roughening treatment on both sides of the "convex" cross-section heat-resistant aluminum alloy profile. Since the cross-section of a single profile within any conductor's vertical section is slightly larger than its original cross-section before twisting, to prevent the n profiles from squeezing together and "bulging," the concentric angle of the roughening die is slightly smaller than the die's central angle. The concentric angle θ of the single profile surface treatment die... 对心角 =θ圆心角 -0.5°, inner surface thread height of 0.04-0.06mm, thread spacing ≤0.1mm.

[0039] The second aspect of the present application provides a preparation method of the aluminum-clad steel core heat-resistant aluminum alloy type wire of the first aspect, comprising the following steps:

[0040] S1, concentrically stranding the aluminum-clad steel wire and the heat-resistant aluminum alloy round wire on the center line core of the aluminum-clad steel wire;

[0041] S2, wrapping the hollow semi-conductive tape on the steel-aluminum mixed stranding layer to form a wrapping layer;

[0042] S3, concentrically stranding the heat-resistant aluminum alloy type wire outside the wrapping layer.

[0043] Further, in S1, the wire laying tension of the aluminum-clad steel wire is 580±5N, and the wire laying tension of the heat-resistant aluminum alloy round wire is 100±2N.

[0044] Further, in S2, the wrapping overlap rate is 45%-50%.

[0045] Further, in S3, the wire laying tension of the heat-resistant aluminum alloy type wire is 100±2N.

[0046] The beneficial effects of the present application are:

[0047] The aluminum-clad steel core heat-resistant aluminum alloy type wire has excellent electrical conductivity, tensile strength, heat resistance and damping properties, specifically:

[0048] The present application improves the electrical conductivity of the heat-resistant aluminum alloy round wire or type wire to more than 62.2% IACS, and the tensile strength to more than 202MPa, reduces the transmission line loss by more than 3.5% under heavy load operation, and increases the rated breaking force of the conductor by more than 10% through the improvement of the composition of the heat-resistant aluminum alloy material, the rolling and heat treatment process of the heat-resistant aluminum alloy rod, the type wire surface treatment process, and the conductor stranding process.

[0049] The present application significantly improves the self-damping performance of the conductor, reduces the conductor fatigue strand caused by wind vibration, and realizes high reliable operation of the transmission line through the design of the steel-aluminum mixed stranding layer, the wrapping layer and the type wire stranding layer. BRIEF DESCRIPTION OF DRAWINGS

[0050] Fig. 1 is a schematic diagram of the structure of the aluminum-clad steel core heat-resistant aluminum alloy type wire of the present application;

[0051] Fig. 2 is a "convex" heat-resistant aluminum alloy type wire drawing die of the present application;

[0052] Fig. 3 is a "convex" heat-resistant aluminum alloy type wire surface treatment die of the present application;

[0053] Figure label explanation: 1, aluminum clad steel wire, 2, heat-resistant aluminum alloy round wire, 3, hollow semi-conductive tape, 4, heat-resistant aluminum alloy profile wire, 5, inner surface of convex thread. DETAILED DESCRIPTION

[0054] The application will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the application and implement it. The embodiments are not limiting to the application.

[0055] Referring to Figure 1, an embodiment of an aluminum clad steel core heat-resistant aluminum alloy profile wire strand of the application is shown, which includes a center line core, a steel-aluminum mixed strand layer concentrically stranded on the center line core, a wrapping layer concentrically wrapped outside the steel-aluminum mixed strand layer, and a profile wire strand layer concentrically stranded outside the wrapping layer; the center line core is an aluminum clad steel wire 1; the steel-aluminum mixed strand layer includes a plurality of aluminum clad steel wires 1 and a plurality of heat-resistant aluminum alloy round wires 2, and the plurality of aluminum clad steel wires 1 do not contact each other; the wrapping layer is a hollow semi-conductive tape 3; the profile wire strand layer is a plurality of heat-resistant aluminum alloy profile wires 4; the electrical conductivity of the heat-resistant aluminum alloy round wire 2 and the heat-resistant aluminum alloy profile wire 4 is ≥62.2% IACS, the tensile strength is ≥202 MPa, and the heat resistance at 280℃, 1h is ≥96%.

[0056] The aluminum clad steel core heat-resistant aluminum alloy profile wire strand of the application uses heat-resistant aluminum alloy round wires 2 and heat-resistant aluminum alloy profile wires 4 with an electrical conductivity of ≥62.2% IACS, which is an improvement of 2.2% IACS or more over the electrical conductivity of 60% IACS of the heat-resistant aluminum alloy round wire used in the existing technology of aluminum clad steel core heat-resistant aluminum alloy strand. In a heavy load running state, the transmission line loss can be reduced by 3.5% or more. At the same time, the tensile strength of the heat-resistant aluminum alloy round wire and profile wire is improved from 159 MPa in the existing technology to 202 MPa or more. In the case of the same specification, the rated breaking force of the aluminum clad steel core heat-resistant aluminum alloy profile wire strand is increased by 10% or more compared to the aluminum clad steel core heat-resistant aluminum alloy strand in the existing technology, which improves the tensile weight ratio of the strand (reduces the sag of the conductor), and increases the ultimate ice thickness by 6mm or more. The wrapping layer is provided, and the hollow semi-conductive tape of the wrapping layer can buffer and reduce the transmission of vibration energy between the outer heat-resistant aluminum alloy profile wire strand layer and the adjacent inner steel-aluminum mixed strand layer, thereby improving the self-damping performance of the conductor.

[0057] Specifically, the steel-aluminum mixed strand layer is one or more layers, and the aluminum clad steel wires 1 and the heat-resistant aluminum alloy round wires 2 in each layer are uniformly distributed. The aluminum clad steel wires 1 in each layer and between layers do not contact each other. Due to the different inherent vibration frequencies of the heat-resistant aluminum alloy round wire 2 and the aluminum clad steel wire 1, when wind vibration occurs, the two types of wire strands in the same layer vibrate and interfere with each other, reducing the vibration energy.

[0058] Preferably, the thickness of the wrapping layer is 0.4 ± 0.02 mm. The cross section of the heat-resistant aluminum alloy wire 4 is "convex" shaped, and the convex angle θ 凸角 = θ 圆心角 / 5, and the two sides of the heat-resistant aluminum alloy wire 4 are roughened surfaces. Adjacent heat-resistant aluminum alloy wire strands rub against each other when vibrating to consume vibration energy, further improving the self-damping performance of the wire.

[0059] Example 1

[0060] This embodiment relates to a method for preparing an aluminum-clad steel-cored heat-resistant aluminum alloy wire strand, comprising the following steps:

[0061] (1) Continuous casting and rolling of heat-resistant aluminum alloy rods:

[0062] a. High-purity aluminum ingots with a purity of 99.90% or higher are melted. Initially, 2 kg of AlB3 per ton of aluminum water is added to the furnace for boronization. Then, according to the actual content of B, V, and Ti, AlB3 is slowly added to gradually reduce the content of V and Ti elements to minimize their impact on the electrical conductivity of the metal material, while controlling B ≤ 0.002wt%;

[0063] b. Once the slag is removed, the sodium particle refining agent and argon are used for primary refining. After 18 minutes of standing, the second slag is removed, and then it is left to stand for another 35 minutes. The primary refining temperature is 785℃;

[0064] c. Aluminum boron intermediate alloy (AlB3), aluminum silicon intermediate alloy (AlSi60), iron agent (75Fe), aluminum zirconium intermediate alloy (AlZr15), aluminum nickel intermediate alloy (AlNi10), aluminum cerium intermediate alloy (AlCe10), aluminum erbium intermediate alloy (AlEr5), and aluminum neodymium intermediate alloy (AlNd30) are added to the aluminum liquid for alloying treatment. The chemical composition of the aluminum liquid finally reaches the specified ratio range: Si 0.09wt%, Fe 0.11wt%, Zr 0.53wt%, Ni 0.08wt%, RE 0.45wt%, where RE is Ce, Er, and Nd with a mass ratio of 3:4:3, the sum of Cr, Mn, V, and Ti is 0.003wt%, and the rest is Al and unavoidable impurities;

[0065] d. The sodium particle refining agent is blown again, and argon is used for secondary refining. After 18 minutes of standing, the slag is removed. During secondary refining, the sodium refining agent is blown again, and the furnace is allowed to stand for 15 minutes to ensure that the particle refining agent fully reacts with the impurities in the aluminum liquid. The secondary refining temperature is 732℃;

[0066] e. The aluminum liquid is poured, and then degassing and double-stage filtration are performed through a degassing tank and a filtering tank;

[0067] f. continuous casting is carried out, wherein the casting temperature is 692℃, the casting speed is 5.7t / h, the cooling water temperature is 22℃, the ejection temperature is 462℃, the supersaturated phase is obtained by high-temperature rapid cooling to improve the electrical properties;

[0068] g. rolling is carried out, which passes through 4 passes of two-roller rolling mill and 8 passes of three-roller rolling mill, to obtain high-conductivity super-heat-resistant aluminum alloy rods with a diameter of 13.6mm, wherein the rolling-in temperature is 420℃, and the finishing temperature is 95℃.

[0069] (2) after heating to 343±3℃ and holding for 72±2h, air cooling to room temperature is carried out for primary heat treatment, heating to 262±2℃ and holding for 33±1h, air cooling to room temperature is carried out for secondary heat treatment, heating to 166±1℃ and holding for 19±0.5h, air cooling to room temperature is carried out for tertiary heat treatment;

[0070] (3) the aluminum alloy rods after heat treatment are drawn through 11 passes of drawing dies to obtain heat-resistant aluminum alloy round wires or heat-resistant aluminum alloy profile wires, wherein the extension coefficient of each pass of drawing die is 1.28.

[0071] When the "convex" heat-resistant aluminum alloy profile wire is prepared by drawing, a "convex" cross-section die is used, as shown in FIG. 2, the central angle θ of the die 圆心角 = 360° / n, wherein n is the number of single wires in the layer, the convex angle θ 凸角 = θ 圆心角 / 5, and the transition angle radius R of the circular arc surface is 0.70±0.05mm.

[0072] The two side surfaces of the heat-resistant aluminum alloy profile wire are roughened, and the heat-resistant aluminum alloy profile wire is drawn by a single-die drawing using a drawing die with two-side convex threads on the inner surface 5, as shown in FIG. 3, the concentric angle θ of the single-profile-wire surface treatment die 对心角 = θ 圆心角 -0.5°, the convex height of the thread on the inner surface compared with the plane is 0.05mm, and the thread spacing is 0.08mm.

[0073] (4) the aluminum-clad mild steel wire and the heat-resistant aluminum alloy round wire are concentrically stranded on the center line core of the aluminum-clad mild steel wire, the wire laying tension of the aluminum-clad mild steel wire is 580±5N, and the wire laying tension of the heat-resistant aluminum alloy round wire is 100±2N;

[0074] (5) the hollow semi-conductive tape is wrapped on the steel-aluminum stranded layer to form a wrapping layer, the wrapping direction is right, the 0.2mm-thick hollow semi-conductive tape is used for overlapping wrapping, and the overlapping rate of the wrapping is 45%-50%;

[0075] (6) the heat-resistant aluminum alloy profile wire is concentrically stranded on the outside of the wrapping layer, and the wire laying tension of the heat-resistant aluminum alloy profile wire is 100±2N.

[0076] Example 2

[0077] This example relates to a preparation method of an aluminum-clad invar core heat-resistant aluminum alloy profile wire, and the difference between this example and example 1 is that 13-die drawing dies are used for drawing, and other steps remain unchanged.

[0078] Example 3

[0079] This example relates to a preparation method of an aluminum-clad invar core heat-resistant aluminum alloy profile wire, and the difference between this example and example 1 is that 9-die drawing dies are used for drawing, and other steps remain unchanged.

[0080] Comparative Example 1

[0081] This comparative example relates to a preparation method of an aluminum-clad invar core heat-resistant aluminum alloy profile wire, and the difference between this comparative example and example 1 is that two-stage heat treatment is used, specifically: after being heated to 420±4℃ for 110±2h and then air-cooled to room temperature, first-stage heat treatment is performed, and then after being heated to 305±3℃ for 45±1h and then air-cooled to room temperature, second-stage heat treatment is performed.

[0082] Other steps remain unchanged.

[0083] The performance indicators of the products of each process in examples 1-3 are shown in Table 1.

[0084] Table 1

[0085] Test Example

[0086] The heat-resistant aluminum alloy wires after the drawing process of the examples and the comparative example are analyzed for various performances, and the results are shown in Table 2.

[0087] Table 2.

[0088] As shown in Table 1-2, the high-conductivity super-heat-resistant aluminum alloy rods with a diameter of 13.6 mm are obtained by rolling the high-conductivity super-heat-resistant aluminum alloy material through two-roller rolling mills for 4 passes and three-roller rolling mills for 8 passes in Examples 1-3, and the heat-resistant aluminum alloy wires with different diameters are obtained by drawing the rods through 9-13 passes, and the tensile strength of the wires is greater than 202 MPa, the tensile strength of the heat-resistant aluminum alloy wire with a conventional diameter of 3.42 mm in Example 1 is 211.3 MPa, which is much higher than 159 MPa in the prior art, and the drawing strength of the wire in Example 2 is as high as 213.9 MPa. The tensile strength of the wire in Comparative Example 1 is only 170.4 MPa under the same rolling and drawing conditions by using a two-stage heat treatment, which is much lower than the tensile strength in Example 1. Therefore, the conductivity of the heat-resistant aluminum alloy round wire or profile wire is improved to be greater than 62.2% IACS, and the tensile strength is improved to be greater than 202 MPa by using the heat-resistant aluminum alloy material composition, the rolling and heat treatment process of the heat-resistant aluminum alloy rod in the application, the transmission line loss is reduced by more than 3.5% under a heavy load running state, and the rated breaking force of the wire is increased by more than 10%.

[0089] The above examples are only preferred examples for fully illustrating the application, and the protection scope of the application is not limited thereto. Any equivalent replacement or transformation of the application by those skilled in the art based on the application is within the protection scope of the application. The protection scope of the application is subject to the claims.

Claims

1. A heat resistant aluminum alloy profiled strand of aluminum clad steel core, characterized in that, The aluminum clad invar core wire includes a center line core, a steel-aluminum mixed stranding layer concentrically stranded on the center line core, a wrapping layer concentrically wrapped outside the steel-aluminum mixed stranding layer, and a profile stranding layer concentrically stranded outside the wrapping layer. The center line core is an aluminum clad invar wire. The steel-aluminum mixed stranding layer includes a plurality of aluminum clad invar wires and a plurality of heat-resistant aluminum alloy round wires, and the plurality of aluminum clad invar wires are not in contact with each other. The wrapping layer is a hollow semi-conductive tape. The profile stranding layer is a plurality of heat-resistant aluminum alloy profiles. The electrical conductivity of the heat-resistant aluminum alloy round wire and the heat-resistant aluminum alloy profile is greater than or equal to 62.2% IACS, the tensile strength is greater than or equal to 202 MPa, and the heat resistance at 280°C for 1h is greater than or equal to 96%.

2. The heat resistant aluminum alloy profiled strand of aluminum clad armor steel core of claim 1 wherein, The heat-resistant aluminum alloy profile section is "convex" shaped, and the convex angle θ 凸角 = θ 圆心角 / 5.

3. The heat resistant aluminum alloy profiled strand of aluminum clad armor steel core of claim 1 wherein, The thickness of the wrapping layer is 0.35-0.45mm.

4. The heat resistant aluminum alloy profiled strand of aluminum clad armor steel core of claim 1 wherein, The preparation method of the heat-resistant aluminum alloy round wire or the heat-resistant aluminum alloy profile is: (1) obtaining an aluminum alloy rod by continuous casting and rolling, and the continuous rolling passes through 4 passes of two-roller rolling mill and 8 passes of three-roller rolling mill; The mass percentage of each component in the aluminum alloy rod is: Si 0.08-0.12wt%, Fe 0.08-0.14wt%, Zr 0.45-0.60wt%, Ni 0.05-0.1wt%, RE 0.4-0.5wt%, wherein RE is: Ce, Er and Nd, the sum of Cr, Mn, V, Ti is less than 0.004wt%, and the rest is Al and unavoidable impurities; (2) heat treating the aluminum alloy rod; (3) drawing the heat-treated aluminum alloy rod to obtain a heat-resistant aluminum alloy round wire or a heat-resistant aluminum alloy profile.

5. The heat resistant aluminum alloy profiled strand of aluminum clad armor steel core of claim 4 wherein, In step (2), the heat treatment is: first-level heat treatment by heating to 343±3℃ for 72±2h and then air cooling to room temperature, second-level heat treatment by heating to 262±2℃ for 33±1h and then air cooling to room temperature, and third-level heat treatment by heating to 166±1℃ for 19±0.5h and then air cooling to room temperature.

6. The heat resistant aluminum alloy profiled strand of aluminum clad armor steel core of claim 4 wherein, In step (3), the diameter of the aluminum alloy rod is 13.6±0.5mm, the drawing adopts 9-13 passes of drawing dies, and the drawing coefficient of the drawing dies is 1.255-1.

305.

7. A method of producing the heat resistant aluminum alloy profiled strand of any one of claims 1 to 6, characterized in that, The method includes the following steps: S1, concentrically stranding an aluminum clad invar wire and a heat-resistant aluminum alloy round wire on an aluminum clad invar wire center line core; S2, wrapping a hollow semi-conductive tape on the steel-aluminum mixed stranding layer to form a wrapping layer; S3, concentrically stranding a heat-resistant aluminum alloy profile outside the wrapping layer.

8. The method for preparing aluminum-clad Invar core heat-resistant aluminum alloy stranded wire as described in claim 7, characterized in that, In S1, the unwinding tension of the aluminum clad invar wire is 580±5N, and the unwinding tension of the heat-resistant aluminum alloy round wire is 100±2N.

9. The method for preparing aluminum-clad Invar core heat-resistant aluminum alloy stranded wire as described in claim 7, characterized in that, In S2, the wrapping overlap rate is 45%-50%.

10. The preparation method of the aluminum clad invar core heat-resistant aluminum alloy profile wire according to claim 7, wherein in S3, the unwinding tension of the heat-resistant aluminum alloy profile is 100±2N.

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