Energy-saving aluminum alloy monofilament of homogenized aluminum base and power transmission conductor

Abstract

The present application relates to the technical field of overhead conductor material for power transmission lines, and provides a simple aluminum-based energy-saving aluminum alloy monofilament, a preparation method and a power transmission conductor. The material takes industrial pure aluminum as a matrix, a small amount of Zr, B, Si elements and TiB2 particles are added, and a melt refining, ultrasonic purification, homogenization treatment, rolling and drawing and multi-stage aging process are combined to realize the synergistic regulation of the microstructure and precipitated phase of the aluminum alloy, reduce the content of impurity elements, and improve the electrical conductivity, strength and heat resistance. The prepared aluminum alloy monofilament has an electrical conductivity of 63.5%IACS at 20 DEG C, a tensile strength of about 150 MPa, and a maximum allowable continuous operating temperature of 150 DEG C, and has high electrical conductivity, high heat resistance and good mechanical properties. The technology reduces the alloying degree and cost through material simple design and multi-field synergistic purification process, is suitable for high-capacity and low-loss power transmission line conductor manufacturing, and has important significance for improving the transmission efficiency and reliability of the power grid.

Description

Technical Field

[0001] This invention belongs to the technical field of overhead conductor materials for power transmission lines, specifically relating to a plain aluminum-based energy-saving aluminum alloy monofilament, its preparation method, and the power transmission conductor. Background Technology

[0002] With the continuous expansion of new energy grid connection and the sustained increase in power system load levels, transmission lines are placing higher demands on the current-carrying capacity, operational reliability, and energy efficiency of aluminum alloy monofilaments. As a key carrier for long-distance power transmission, the material properties of overhead transmission conductors directly affect transmission capacity, line losses, operating temperature, and service life. In the existing power grid structure, aluminum-based aluminum alloy monofilaments are widely used in various overhead transmission lines due to their light weight, moderate cost, and good conductivity. However, with the increase in transmission capacity and the rise in high-temperature operating conditions, traditional aluminum-based aluminum alloy monofilaments are gradually showing certain limitations in terms of overall performance.

[0003] Currently, commonly used overhead conductor materials mainly include hard aluminum conductors, soft aluminum conductors, and heat-resistant aluminum alloy conductors. Hard aluminum conductors have certain strength and processing stability, but their conductivity and heat resistance are limited under high-load operating conditions, and their long-term operating temperature is relatively low, making it difficult to meet the requirements of high-temperature, high-capacity power transmission scenarios. Soft aluminum alloy monofilaments can achieve higher conductivity and better conductivity stability through annealing, but their mechanical strength is relatively low, which limits their application in lines with large spans or high mechanical loads. Heat-resistant aluminum alloy monofilaments improve high-temperature stability by adding alloying elements, allowing the conductor to maintain certain mechanical properties and structural stability at higher temperatures, but there is still room for improvement in conductivity, and the material cost and manufacturing complexity also increase accordingly.

[0004] As the operating temperature of transmission lines increases, the thermal expansion behavior, recrystallization resistance, and long-term thermal stability of aluminum alloy monofilaments are becoming increasingly important parameters affecting the safe operation of these lines. Currently, improving the heat resistance of aluminum-based aluminum alloy monofilaments typically involves increasing the content of alloying elements. However, the introduction of multiple alloying elements can negatively impact the material's conductivity and may lead to more complex manufacturing processes and increased resource consumption. Furthermore, the content of impurity elements, the morphology of precipitated phases, and the microstructure of the aluminum alloy monofilament all affect its overall performance. Therefore, achieving a balance between strength and heat resistance while maintaining conductivity is a key focus in the current application and development of aluminum-based transmission aluminum alloy monofilaments.

[0005] In actual production, aluminum-based alloy monofilaments typically undergo multiple processes including melting, refining, casting, rolling, drawing, and heat treatment. The conditions of each process significantly impact the material's microstructure and final properties. Under different process conditions, factors such as the distribution of alloying elements, inclusion content, and gas content can all affect the material's stability and consistency. Therefore, under current technological conditions, obtaining aluminum-based alloy monofilaments with stable properties while ensuring production feasibility and cost control remains a key area of ​​ongoing concern in related technical fields.

[0006] In summary, existing aluminum alloy monofilaments for overhead power transmission still have room for improvement in balancing conductivity, heat resistance, and mechanical properties. Furthermore, there is a need for further optimization in material composition design and the stability of manufacturing processes. To meet the development requirements of high-capacity, low-loss, and highly reliable operation of power transmission lines, developing aluminum-based alloy monofilaments with stable overall performance suitable for power transmission conductors, and their manufacturing technology, has become one of the urgent technological directions to be addressed in this field. Summary of the Invention

[0007] The purpose of this invention is to solve the problems in the prior art where it is difficult to balance the conductivity, heat resistance and mechanical properties of aluminum-based aluminum alloy monofilaments used in overhead power transmission lines, and the high degree of alloying and high cost make it difficult to meet the requirements of high-capacity and low-loss power transmission.

[0008] The objective of this invention is achieved through the following technical solution: A type of plain aluminum-based energy-saving aluminum alloy monofilament is composed of the following components by mass percentage: Zr: 0.03%~0.05%, Ti: 0.05%~0.10%, B: 0.002%~0.015%, other impurity elements ≤0.004%, and the balance being Al.

[0009] Preferably, the microstructure of the unrefined aluminum-based energy-saving aluminum alloy monofilament contains dispersed Al3Zr phase and TiB2 particles.

[0010] Preferably, the tensile strength of the plain aluminum-based energy-saving aluminum alloy monofilament is ≥150MPa.

[0011] Preferably, the Zr content is 0.04% to 0.05%, the Ti content is 0.05% to 0.08%, and the B content is 0.008% to 0.015%.

[0012] Based on the same inventive concept, the present invention also provides a method for preparing the aforementioned plain aluminum-based energy-saving aluminum alloy monofilament, comprising the following steps: After melting industrial pure aluminum ingots to 720℃~750℃, Al-TiB2 master alloy is added and the temperature is held. Then Al-Zr master alloy is added and electromagnetic stirring is performed multiple times to obtain alloy melt. The alloy melt is then refined with inert gas and ultrasonically purified before being cast into aluminum alloy ingots. The aluminum alloy ingot is subjected to a two-stage homogenization treatment and rolled into an aluminum alloy round rod; Aluminum alloy monofilaments are obtained by drawing the aluminum alloy round rod in multiple passes. The aluminum alloy monofilament is obtained by aging treatment.

[0013] Preferably, the frequency of the ultrasonic purification treatment is 15–20 kHz, and the power density is 150–200 W / cm². 2 The processing time is 8–12 min to improve the uniformity of Al3Zr phase and TiB2 particle distribution.

[0014] Preferably, the two-stage homogenization process includes: first holding at 300℃~320℃ for 4~8h, then raising the temperature to 480℃~500℃ at a heating rate of 50℃ / h and holding for 6~10h, so as to promote the precipitation of Zr element and the formation of a stable dispersed phase.

[0015] Preferably, after the drawing is completed, the aluminum alloy monofilament is subjected to aging treatment at 170℃~220℃ for 4~6 hours to obtain a stable precipitation-strengthened structure and electrical conductivity.

[0016] Preferably, the inert gas refining includes: treatment with argon-injected powder refining agent, wherein the amount of refining agent added is 0.25% to 0.30% of the total furnace charge, in order to reduce the hydrogen content and inclusion content in the melt.

[0017] Based on the same inventive concept, the present invention also provides a power transmission conductor, the power transmission conductor comprising a conductor, the conductor comprising the aforementioned plain aluminum-based energy-saving aluminum alloy monofilament.

[0018] Preferably, the conductor is a conductor structure formed by stranding multiple aluminum alloy monofilaments with a diameter of 3.0 mm to 4.0 mm.

[0019] Preferably, the transmission conductor is used for overhead transmission lines with a continuous operating temperature of not less than 150°C, so as to maintain low resistivity and stable mechanical properties under high-temperature operating conditions.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention addresses the need for synergistic improvement of the conductivity, mechanical properties, and heat resistance of aluminum alloy monofilaments in overhead power transmission lines. It proposes a composition and preparation process system for aluminum-based aluminum alloy monofilaments based on the concept of material optimization. By using high-purity industrial aluminum as the matrix and controlling the addition amounts of elements such as Zr, B, and Si, while simultaneously introducing TiB2 dispersed particles and combining this with melt purification, homogenization treatment, and multi-stage aging processes, comprehensive control over the morphology of precipitated phases, impurity content, and grain structure can be achieved at the microstructure level, thereby constructing a stable and uniform strengthening and conductive structural system. In this system, Zr forms a thermally stable Al3Zr dispersed phase under suitable heat treatment conditions. This phase is coherent with the aluminum matrix, suppressing recrystallization and grain coarsening at higher temperatures, thus improving the material's high-temperature strength retention. Simultaneously, by controlling process parameters to promote its fine and uniform precipitation, heat resistance can be enhanced without significantly reducing electron mobility. Boron in the melt can form borides with transition impurities, thereby reducing the solid solution content of impurities such as Mn, Cr, V, and Ti, decreasing free electron scattering centers, lowering resistivity, and maintaining high conductivity in the conductor. Si, under trace amounts, participates in regulating the thermal expansion behavior of the matrix, resulting in better dimensional stability of the material at high temperatures. TiB2 particles form dispersed heterogeneous nucleation sites in the melt, which not only helps refine the grains but also enhances the tensile strength and creep resistance of the material through particle strengthening. The synergistic effect of this compositional design and microstructure regulation allows the material to maintain high conductivity while achieving stable mechanical and thermal properties.

[0021] In terms of preparation process, electromagnetic stirring and inert gas refining after melting promote uniform distribution of alloying elements and reduce inclusions and gas content, thereby improving melt purity. Ultrasonic melt purification technology further accelerates inclusion flotation and refines the distribution of Al3Zr and TiB2 phases, resulting in smaller and more dispersed precipitates, thus reducing local stress concentration and improving microstructure stability. Subsequently, a two-stage homogenization process, along with appropriate rolling, drawing, and multi-stage aging processes, regulates the Zr precipitation kinetics, forming a stable nanoscale dispersed phase structure while maintaining the continuity of free electron migration channels in the matrix. This microstructure maintains high strength and resistance to softening under high-temperature operating conditions and reduces performance degradation caused by thermal expansion, enabling the material to retain stable electrical and mechanical properties even at high continuous operating temperatures. Through the synergistic effect of the above-mentioned technical features, the material can achieve high conductivity and high tensile strength at room temperature, while maintaining good mechanical stability and low loss characteristics under high temperature operating conditions. This is beneficial to improving the transmission efficiency and operational reliability of power transmission lines, and to a certain extent reducing the degree of material alloying and production costs. It has good engineering application value and promotion potential. Detailed Implementation

[0022] The technical solution will be further described below with reference to specific embodiments to help understand the content of the present invention.

[0023] Example 1 A type of plain aluminum-based energy-saving aluminum alloy monofilament is composed of the following components by mass percentage: Zr: 0.03%~0.05%, Ti: 0.05%~0.10%, B: 0.002%~0.015%, other impurity elements ≤0.004%, and the balance being Al.

[0024] Preferably, the microstructure of the unrefined aluminum-based energy-saving aluminum alloy monofilament contains dispersed Al3Zr phase and TiB2 particles.

[0025] Preferably, the tensile strength of the plain aluminum-based energy-saving aluminum alloy monofilament is ≥150MPa.

[0026] Preferably, the Zr content is 0.04% to 0.05%, the Ti content is 0.05% to 0.08%, and the B content is 0.008% to 0.015%.

[0027] The present invention relates to the preparation of plain aluminum-based energy-saving aluminum alloy monofilaments by adding only Al-Zr and Al-TiB2 alloys. Through smelting, electromagnetic stirring, long-life ceramic ultrasonic treatment, drawing, and double-stage aging, high-performance plain aluminum alloy power transmission conductor materials are prepared. The preparation process is simple and low-cost, and the prepared materials have excellent mechanical and electrical properties.

[0028] The roles and mechanisms of each alloying element are as follows: 1) Zr: Zirconium is one of the main alloying elements, significantly affecting the microstructure and properties of alloys. Zirconium can form an Al3Zr phase with an aluminum matrix, exhibiting good thermal stability, coherence with the aluminum matrix, and low lattice mismatch. However, the low diffusion rate of Zr results in slow and uneven precipitation of the Al3Zr phase. While Zr is beneficial for improving the alloy's heat resistance, excessive Zr addition can negatively impact electrical conductivity. Therefore, accelerating the precipitation kinetics of Al3Zr, promoting the age-dependent precipitation of Zr atoms, and improving the size and distribution of the Al3Zr precipitate phase are key to improving the properties of Al-Zr alloys.

[0029] 2) B: Reducing impurity elements helps improve the conductivity of aluminum conductors. Boring is an effective method to reduce impurity content. Reasonable boring treatment can cause transitional impurity elements in the ingot to form borides and deposit them at the bottom of the furnace, reducing the content of Mn, Cr, V and Ti impurity elements in the aluminum liquid, achieving the purpose of purification, and helping to improve the conductivity of aluminum alloys.

[0030] 3) Si: Adding an appropriate amount of Si to the aluminum matrix can increase the primary silicon and eutectic silicon phases in the alloy, which is beneficial to reducing the thermal expansion coefficient of the alloy and thus improving its stability in high-temperature environments.

[0031] 4) V, Mn, Cr, and Ti: These four elements are impurities in electrical-grade pure aluminum. When Cr, Mn, V, and Ti impurities exist in a solid solution state in aluminum, they easily absorb free electrons from the material and fill their incomplete electron layers. The reduced number of free electrons that contribute to conductivity leads to an increase in the resistivity of the aluminum. Studies have shown that 1% (Cr+Mn+V+Ti) of impurities has a five times greater detrimental effect on the conductivity of aluminum conductors than 1% of Si. Therefore, strictly controlling the content of Cr, Mn, V, and Ti impurities is crucial for ensuring the conductivity of aluminum conductors.

[0032] The specific preparation of the plain aluminum-based energy-saving aluminum alloy monofilament of the present invention includes the following steps: Step 1: Melting: Select industrial pure aluminum ingots (purity ≥ 99.7%) and add them to the melting furnace for melting. The melting temperature is maintained at 720℃~750℃. After the industrial pure aluminum ingots are completely melted, add Al-5wt.%TiB2 alloy at 720℃~730℃. After standing for 30 min, keep the temperature at 720℃~730℃ and add Al-5%Zr master alloy. After the master alloy is completely melted, electromagnetically stir the aluminum alloy liquid for 10~15 min each time, for a total of 3 times, with an interval of 10~15 min between each stirring.

[0033] Step 2 Refining: The temperature of the aluminum alloy solution is controlled within the range of 740~760℃. An inert argon gas (99.99% purity) is used to inject a powdered refining agent into the bottom of the aluminum alloy solution obtained in Step 1). After 10~15 minutes of aeration, the solution is stirred for 20 minutes, then allowed to stand for 30 minutes before slag removal. The amount of refining agent added is approximately 0.25%~0.30% of the total furnace charge. Step 3: Ultrasonic Melt Purification: The melt is ultrasonically treated using a long-life ceramic ultrasonic stirring head to improve the distribution of Al-Zr and TiB2 phases and the metallurgical quality of the melt. The ultrasonic frequency is 15-20kHz, and the power density is 150-200W / cm³. 2 The processing time is 10 minutes to accelerate the separation of inclusions, reduce hydrogen concentration and porosity, control potential defect risks, and improve melt purity. Step 4: Settle the aluminum melt evenly with a layer of covering agent and keep it at a temperature of 740~760℃ for at least 30 minutes. Step 5: Casting: After the aluminum alloy liquid is filtered through an alumina ceramic filter, it is cast into a ceramic mold at 750~760℃ to prepare aluminum alloy ingots. Step 6 Homogenization and Rolling: After holding the aluminum alloy ingot obtained in step 5) at 300℃~320℃ for 4~8h, the temperature is raised to 480℃~500℃ at a heating rate of 50℃ / h and held for 6~10h. After cooling to 400℃~450℃, it is continuously rolled into an aluminum alloy round rod with a diameter of Ф9.5 mm by a rolling mill. Step 7: Wire drawing: The aluminum alloy round rod obtained in step 6) is drawn on a wire drawing machine at a speed of 6~8 m / s and the wire drawing temperature is 40~45℃; with special wire drawing oil and nano mold, after 12 drawing passes, an aluminum alloy round monofilament with a diameter of Ф3.84 mm is obtained. Step 8 Aging treatment: The aluminum alloy round monofilament obtained in step 7) is aged in a box-type heat treatment furnace for 4~6 hours at an aging temperature of 170℃~220℃; after aging, it is air-cooled to room temperature with the furnace to finally obtain an aluminum alloy monofilament conductor material with a diameter of 3.84 mm.

[0034] The high-conductivity, ultra-heat-resistant aluminum alloy conductor material provided by this invention has a room temperature conductivity of 63.5% IACS, a tensile strength of 150 MPa, and a maximum allowable continuous operating temperature of 150°C.

[0035] This invention, by adding Zr and B elements to aluminum alloys, can not only reduce the content of impurities such as Cr, Mn, V, and Ti in aluminum alloys, thereby improving electrical conductivity, but also accelerate the precipitation kinetics of the dominant element Zr, thereby improving the heat resistance of the alloy. Furthermore, it can improve the mechanical properties of aluminum alloys through the dispersed distribution of TiB2 particles in the aging precipitate phase, thus ensuring that the aluminum alloy material has good mechanical-electrical-thermal properties.

[0036] Its technological features are as follows: First, smelting is carried out. After the industrial pure aluminum ingot is completely melted at 730℃~750℃, Al-5wt.% TiB2 alloy is added at 720℃~730℃, followed by Al-Zr master alloy at 720℃~730℃. The alloying elements are fully homogenized by stirring. A refining agent is used to remove hydrogen and slag from the aluminum liquid. Ultrasonic melt treatment is used to purify the melt, control melt defects, and improve melt quality. A two-stage homogenization process is used to ensure the alloying elements fully precipitate and react, accelerating Zr precipitation. Simultaneously, Zr combines with impurities in the alloy to form the TiB2 phase. The precipitated phase is small in size and uniformly distributed, effectively improving the thermal-electric properties and recrystallization resistance of the aluminum alloy. After homogenization, the aluminum ingot is rolled into a φ9.5 mm aluminum alloy round rod. The φ9.5 mm aluminum alloy round rod is drawn at a speed of 6~8 m / s on a wire drawing machine, and after 12 passes, a φ3.84 is obtained. The aluminum alloy round monofilament is made of mm. The aluminum alloy round monofilament is heat-treated in a box-type heat treatment furnace at an aging temperature of 170℃~220℃ for 4~6 hours. After aging, it is air-cooled to room temperature to finally obtain an aluminum alloy wire with a diameter of φ3.84 mm.

[0037] This invention, by adding trace amounts of TiB2 to an Al-Zr alloy and employing a two-stage homogenization process after casting and a heat treatment after drawing, utilizes fewer alloying elements while achieving better results. This improves the heat resistance and strength of the aluminum alloy while maintaining its electrical conductivity, thereby producing an alloy with room temperature (20°C) conductivity. 63.5% IACS, tensile strength A plain aluminum-based energy-saving conductor material for overhead conductors with a strength of 150MPa and a heat resistance temperature of up to 150℃.

[0038] This invention achieves a synergistic improvement in conductivity, tensile strength and heat resistance of aluminum alloy monofilaments through composition design and process optimization based on material simplification theory. Its core beneficial technical effects are realized through the following specific technical features and working principles.

[0039] First, this invention employs a specific combination of alloying elements and an impurity control strategy. Specifically, by optimizing the content of Zr, B, and Si and introducing TiB2 particles, a "main alloying element-dominated + micro-precise doping" alloying material system is constructed. The principle is that zirconium, as the main alloying element, can form an Al3Zr phase with an L12 structure with the aluminum matrix. This phase has good thermal stability and is coherent with the matrix, effectively pinning dislocations and grain boundaries, thus significantly improving the alloy's heat resistance. The addition of boron, through borylation treatment, combines with transition metal impurities such as Cr, Mn, V, and Ti in the molten aluminum to form high-density boride deposits, thereby purifying the melt and significantly reducing the scattering of free electrons by impurity elements, thus improving conductivity. Simultaneously, the introduction of TiB2 particles not only refines the grain size but also enhances the alloy's mechanical properties through dispersed distribution. This design allows the material to overcome the low conductivity of traditional heat-resistant aluminum alloys and avoid the insufficient strength of soft aluminum by adding only a small amount of alloying elements. Ultimately, it achieves excellent comprehensive performance with a conductivity of 63.5% IACS, a tensile strength of 150MPa, and a heat resistance of 150℃, effectively reducing production costs and dependence on natural resources.

[0040] Secondly, this invention employs a long-life ceramic ultrasonic melt purification technology during the preparation process, a key technological feature for improving the metallurgical quality and performance of the material. The principle is that ultrasonic treatment generates high-frequency vibrations and cavitation effects in the melt, accelerating the polymerization and flotation of micro-inclusions and gases, thereby significantly reducing the hydrogen concentration and porosity in the melt and improving the distribution of the Al-Zr and TiB2 phases. This is achieved by controlling the ultrasonic frequency to 15-20 kHz and the power density to 150-200 W / cm³. 2By controlling processing time, this technology effectively manages the potential defect risks of the melt and improves melt purity. The direct technical effect of this feature is a significant reduction in microscopic defects within the material and a decrease in electron scattering sources. This, in turn, ensures high material purity while providing a clean microstructure foundation for subsequent high conductivity and excellent mechanical properties.

[0041] Finally, this invention employs a unique high-temperature rolling and two-stage aging process, specifically optimizing the technical challenges of slow and uneven Al3Zr phase precipitation. The principle is that the two-stage homogenization treatment first uses a holding temperature of 300℃~320℃ to promote the dissolution of the primary phase and the nucleation of precipitated phases, followed by a heating to 480℃~500℃ for holding to promote the uniform precipitation and growth of the Al3Zr phase. This heat treatment regime effectively accelerates the aging precipitation kinetics of Zr atoms, improving the size and distribution of the precipitated phases. Simultaneously, the subsequent drawing and aging treatment at 170℃~220℃ further adjust the dislocation structure and precipitation strengthening effect of the microstructure. This process characteristic results in small and dispersed precipitated phases within the alloy, significantly improving the alloy's resistance to recrystallization and high-temperature stability. The beneficial effects are that the aluminum alloy monofilament can still maintain high strength at high temperatures (such as a strength retention rate of over 95% at 230℃ / 1h), and the optimized microstructure reduces the negative impact of lattice distortion on conductivity, thus perfectly balancing the mechanical, electrical, and thermal properties and meeting the stringent requirements of new power systems for large-capacity, low-loss power transmission.

[0042] Examples 2-7 A type of plain aluminum-based energy-saving aluminum alloy monofilament is composed of the following components by mass percentage: Zr: 0.03%~0.05%, Ti: 0.05%~0.10%, B: 0.002%~0.015%, other impurity elements ≤0.004%, and the balance being Al.

[0043] Examples 2 to 7 all use existing smelting, filtering, casting, rolling, wire drawing and aging treatment equipment, and are carried out according to the steps described in Example 1; however, Example 7 does not use ultrasonic melt purification treatment.

[0044] Table 1. Composition of aluminum alloy monofilaments in Examples 2-7 (wt.%)

[0045] The material simplification scheme provided by this invention reduces the use of rare earth elements, which can effectively save raw material costs and achieve the goal of synergistic improvement of multiple properties.

[0046] Table 2 Performance test results of aluminum alloy monofilaments in Examples 2-7

[0047] As shown in Table 2, the aluminum alloy conductor material of the present invention has significant advantages in comprehensive performance. In particular, the room temperature (20°C) conductivity of the optimal embodiment 5 reaches 63.5% IACS, the room temperature tensile strength is 150MPa, and the heat resistance temperature reaches 150°C.

[0048] Examples 8-12 Based on the same inventive concept, the present invention also provides a method for preparing plain aluminum-based energy-saving aluminum alloy monofilament as described in Example 1, comprising the following steps: After melting industrial pure aluminum ingots to 720℃~750℃, Al-TiB2 master alloy is added and the temperature is held. Then Al-Zr master alloy is added and electromagnetic stirring is performed multiple times to obtain alloy melt. The alloy melt is then refined with inert gas and ultrasonically purified before being cast into aluminum alloy ingots. The aluminum alloy ingot is subjected to a two-stage homogenization treatment and rolled into an aluminum alloy round rod; Aluminum alloy monofilaments are obtained by drawing the aluminum alloy round rod in multiple passes. The aluminum alloy monofilament is obtained by aging treatment.

[0049] Preferably, the frequency of the ultrasonic purification treatment is 15–20 kHz, and the power density is 150–200 W / cm². 2 The processing time is 8–12 min to improve the uniformity of Al3Zr phase and TiB2 particle distribution.

[0050] Preferably, the two-stage homogenization process includes: first holding at 300℃~320℃ for 4~8h, then raising the temperature to 480℃~500℃ at a heating rate of 50℃ / h and holding for 6~10h, so as to promote the precipitation of Zr element and the formation of a stable dispersed phase.

[0051] Preferably, after the drawing is completed, the aluminum alloy monofilament is subjected to aging treatment at 170℃~220℃ for 4~6 hours to obtain a stable precipitation-strengthened structure and electrical conductivity.

[0052] Preferably, the inert gas refining includes: treatment with argon-injected powder refining agent, wherein the amount of refining agent added is 0.25% to 0.30% of the total furnace charge, in order to reduce the hydrogen content and inclusion content in the melt.

[0053] The present invention uses five examples, 8-12, to verify the effectiveness and beneficial technical effects of the preparation method. The specific process parameters are shown in Tables 3 and 4 below.

[0054] Table 3. Melting-Refining-Ultrasonic-Setting-Casting Section

[0055] Table 4. Homogenization-Rolling-Drawing-Aging Section

[0056] In terms of material design, this invention proposes a composition design concept for ultra-heat resistant aluminum alloys based on the saturation theory. By combining the main alloying element as the dominant element with precise micro-doping, impurity elements are precipitated, achieving precise control over the material composition and microstructure. In terms of process control, a multi-field synergistic melt purification technology is adopted, which effectively avoids compositional segregation during multi-element melting and significantly reduces oxidation and inclusion formation during melting, thereby greatly improving melt purity and the overall performance of the final product.

[0057] Example 13 Based on the same inventive concept, the present invention also provides a power transmission conductor, the power transmission conductor comprising a conductor, the conductor comprising a plain aluminum-based energy-saving aluminum alloy monofilament as described in Example 1.

[0058] Preferably, the conductor is a conductor structure formed by stranding multiple aluminum alloy monofilaments with a diameter of 3.0 mm to 4.0 mm.

[0059] Preferably, the transmission conductor is used for overhead transmission lines with a continuous operating temperature of not less than 150°C, so as to maintain low resistivity and stable mechanical properties under high-temperature operating conditions.

[0060] The transmission conductor provided in this embodiment significantly improves the transmission capacity and efficiency of the conductor in high-temperature environments by using a plain aluminum-based energy-saving aluminum alloy monofilament with high conductivity (63.5% IACS) and high heat resistance (150℃) as the conductor. Utilizing the excellent mechanical-electrical-thermal synergistic properties of the monofilament, this conductor maintains low resistivity and stable mechanical properties even under harsh conditions of continuous operating temperature not lower than 150℃. This effectively solves the technical problems of poor heat resistance or low conductivity in traditional conductors, enabling high-capacity, low-loss, and safe and stable operation of overhead transmission lines.

[0061] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention.

Claims

1. A plain aluminum-based energy-saving aluminum alloy monofilament, characterized in that, Composed of the following components by mass percentage Composition: Zr: 0.03%~0.05%, Ti: 0.05%~0.10%, B: 0.002%~0.015%, total amount of other impurity elements ≤0.004%, balance is Al.

2. The plain aluminum-based energy-saving aluminum alloy monofilament according to claim 1, characterized in that, The microstructure of the unrefined aluminum-based energy-saving aluminum alloy monofilament contains dispersed Al3Zr phase and TiB2 particles.

3. The plain aluminum-based energy-saving aluminum alloy monofilament according to claim 1, characterized in that, The tensile strength of the plain aluminum-based energy-saving aluminum alloy monofilament is ≥150MPa.

4. The plain aluminum-based energy-saving aluminum alloy monofilament according to claim 1, characterized in that, The Zr content is 0.04%–0.05%, the Ti content is 0.05%–0.08%, and the B content is 0.008%–0.015%.

5. A method for preparing a plain aluminum-based energy-saving aluminum alloy monofilament as described in any one of claims 1 to 4, characterized in that, Includes the following steps: After melting industrial pure aluminum ingots to 720℃~750℃, Al-TiB2 master alloy is added and kept at the temperature. Then Al-Zr master alloy is added and electromagnetic stirring is performed multiple times to obtain alloy melt. The alloy melt is then refined with inert gas and ultrasonically purified before being cast into aluminum alloy ingots. The aluminum alloy ingot is subjected to a two-stage homogenization treatment and rolled into an aluminum alloy round rod; Aluminum alloy monofilaments are obtained by drawing the aluminum alloy round rod in multiple passes. The aluminum alloy monofilament is obtained by aging treatment.

6. The preparation method according to claim 5, characterized in that, The ultrasonic purification process has a frequency of 15–20 kHz and a power density of 150–200 W / cm². 2 The processing time is 8–12 min to improve the uniformity of Al3Zr phase and TiB2 particle distribution.

7. The preparation method according to claim 5, characterized in that, The two-stage homogenization process includes: first, holding at 300℃~320℃ for 4~8h, then raising the temperature to 480℃~500℃ at a heating rate of 50℃ / h and holding for 6~10h to promote the precipitation of Zr elements and the formation of a stable dispersed phase.

8. The preparation method according to claim 5, characterized in that, After the drawing is completed, the aluminum alloy monofilament is subjected to aging treatment at 170℃~220℃ for 4~6 hours to obtain a stable precipitation-strengthened structure and electrical conductivity.

9. The preparation method according to claim 5, characterized in that, The inert gas refining process includes: treatment with argon-injected powder refining agent, with the amount of refining agent added being 0.25% to 0.30% of the total furnace charge, in order to reduce the hydrogen content and inclusion content in the melt.

10. A power transmission conductor, characterized in that, The power transmission conductor includes a conductor, which includes the plain aluminum-based energy-saving aluminum alloy monofilament as described in any one of claims 1 to 4.

11. The power transmission conductor according to claim 10, characterized in that, The conductor is a conductor structure formed by twisting together multiple aluminum alloy monofilaments with a diameter of 3.0 mm to 4.0 mm.

12. The power transmission conductor according to claim 10, characterized in that, The transmission conductors are used for overhead transmission lines with a continuous operating temperature of not less than 150°C, in order to maintain low resistivity and stable mechanical properties under high-temperature operating conditions.

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