High-strength and high-conductivity aluminum alloy conductor material for high-voltage switch equipment and preparation method and application of high-strength and high-conductivity aluminum alloy conductor material

Abstract

The invention discloses a high-strength and high-conductivity aluminum alloy conductor material for high-voltage switch equipment as well as a preparation method and application of the high-strength and high-conductivity aluminum alloy conductor material, and relates to the field of high-voltage electrical equipment manufacturing and the technical field of aluminum alloy materials. The conductor material comprises the following components in percentage by mass: 0.3%-0.6% of Si, less than or equal to 0.40% of Fe, less than or equal to 0.10% of Cu, less than or equal to 0.03% of Mn, 0.35%-0.8% of Mg, 0.10%-0.15% of Er, 0.08%-0.10% of La, less than or equal to 0.03% of Cr, less than or equal to 0.06% of B and less than or equal to 0.10% of other impurity elements in total. The preparation method comprises the following steps: smelting the Er and La rare earth modified alloy; pouring is conducted; performing homogenizing treatment; performing extrusion treatment; and carrying out stretch straightening and solid solution and aging treatment. According to the prepared aluminum alloy conductor, under the same voltage grade and current, the temperature rise value of the conductor with the same specification is reduced by more than 10% compared with that of a 6063-T6 state aluminum alloy conductor.

Description

Technical Field

[0001] This invention relates to the fields of high-voltage electrical equipment manufacturing and aluminum alloy material technology, and more specifically to a high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear, its preparation method, and its application. Background Technology

[0002] Aluminum alloy conductors are critical components used extensively in high-voltage switchgear, and their manufacturing costs and electromechanical performance significantly impact switchgear products. With the development of high-capacity, high-current-carrying, and miniaturized high-voltage switchgear, it is crucial to address the current-carrying bottleneck in busbar technology while ensuring product performance. The annual consumption of 6063-T6 aluminum alloy tubing, commonly used in high-voltage switchgear busbar conductors, is nearly ten thousand tons, accounting for a significant portion of switchgear manufacturing costs. Reducing raw material usage to lower manufacturing costs can significantly improve the profitability of switchgear products; furthermore, it can provide a solution to the current-carrying challenges of busbars in high-capacity, high-current-carrying, and compact switchgear products.

[0003] In the field of aluminum alloy materials, both domestically and internationally, methods such as ceramic reinforcement can improve their mechanical properties, but this leads to a decrease in their conductivity. There are currently few researches on technologies that can achieve both simultaneously. In the field of high-voltage switches, 6063-T6 aluminum alloy conductors are the most widely used. To ensure and improve the current-carrying capacity of the conductors, the current common approach is to increase the wall thickness of the aluminum alloy tube or to use copper tubes instead of aluminum tubes. However, both approaches significantly increase the manufacturing cost of switch products, and there are currently no alternative conductor materials or corresponding profiles.

[0004] In recent years, extensive research has been conducted both domestically and internationally on aluminum as a conductor material, leading to the development of heat-resistant aluminum alloy wires, high-strength aluminum alloy wires, and all-aluminum alloys. The primary application of aluminum conductors is in overhead transmission lines. Well-known domestic and international power companies such as ABB, Siemens, Xi'an Kaifa, and Pinggao mainly use 6063 aluminum alloy profiles for their aluminum alloy conductors, and in large quantities. There are no precedents for the application of high-conductivity aluminum alloy profiles. However, with the development of high-voltage switches towards larger capacity, smaller size, and lighter weight, the research and application of high-conductivity aluminum alloy profiles is imperative.

[0005] The main conductor profiles used in high-voltage switchgear are 6063-T6, with a tensile strength ≥215MPa and conductivity ≥51%IACS. However, the national standard 6101-T6 treated material has a tensile strength ≥195MPa and conductivity ≥55%IACS. In reality, most 6101 aluminum alloy suppliers struggle to meet the 55% IACS conductivity standard for their tubing. Addressing this situation and the current-carrying technology bottleneck in large-capacity, compact switchgear, this invention achieves simultaneous improvement in conductivity and mechanical properties through overall control of the 3rd component of 6101 aluminum alloy, profile preparation, and heat treatment processes. This enhances the conductor's current-carrying capacity, solves the current-carrying technology problem in large-capacity, compact switchgear products, effectively reduces production costs, and improves the market competitiveness of switchgear. It can be used in the manufacture of conductor profiles for all series of high-voltage switchgear. Summary of the Invention

[0006] In view of this, the present invention provides a high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear, its preparation method, and its application. The present invention achieves a precise balance between strength and conductivity through optimized control of the heat treatment process: a low-temperature aging process is employed to control the precipitated phases and their size, reducing electron scattering and the obstruction of electrons by dislocations; furthermore, the addition of Er and La erbium may lower the aging temperature or shorten the aging time, reducing the supersaturation solid solution of alloying elements while ensuring strength, thereby improving conductivity and avoiding excessive strengthening that leads to decreased conductivity.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear, comprising the following components by mass percentage: Silicon (Si): 0.3%~0.6%, Iron (Fe): ≤0.40%, Copper (Cu): ≤0.10%, Manganese (Mn): ≤0.03%, Magnesium (Mg): 0.35%~0.8%, Erbium (Er): 0.10%~0.15%, Lanthanum (La): 0.08%~0.10%, Chromium (Cr): ≤0.03%, Boron (B): ≤0.06%, and other impurity elements total ≤0.10%.

[0008] This invention modifies 6101 aluminum alloy by adding rare earth elements Er and La. Er and La, as rare earth elements, can achieve a synergistic improvement in the strength and conductivity of the aluminum alloy through microstructure optimization and impurity purification.

[0009] In terms of electrical conductivity, the electrical conductivity of aluminum alloys is mainly affected by the scattering effect of solid solution atoms and the second phase. Er and La reduce the scattering of free electrons by transition elements (such as Fe and Mn) dissolved in the matrix through the "purification effect". At the same time, Er can inhibit the recrystallization of aluminum alloys during rolling or annealing, refine the grains and control the distribution of grain boundaries, and reduce the scattering of electrons by grain boundaries. La can coordinate the balance between grain size and electrical conductivity by promoting recrystallization nucleation, and avoid the electrical anisotropy caused by coarse grains.

[0010] In terms of strength, Er and La can form dispersed rare earth phases (such as Al3Er and Al11La3) in aluminum alloys, which act as heterogeneous nucleation cores to refine grains and hinder dislocation movement. This enhances alloy strength through grain refinement and precipitation strengthening. Simultaneously, it can transform the morphology of traditional precipitates (such as β-AlFeSi) from needle-like or lamellar to granular, reducing the cutting effect on the matrix and improving alloy plasticity and strength. The combined addition of Er and La leverages the advantages of both rare earth elements: Er primarily focuses on precipitation strengthening and recrystallization suppression, while La emphasizes impurity purification and precipitate phase control. Together, they optimize the "strength-conductivity" performance.

[0011] Another object of the present invention is to provide a method for preparing a high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear, comprising the following steps: (1) Based on the chemical composition of the above high-strength and high-conductivity aluminum alloy material, weigh industrial pure aluminum, AlEr10 master alloy, AlLa10 master alloy, pure magnesium, pure zinc, Al 50Cu master alloy, Al B master alloy and Al Mn master alloy according to the metric ratio and prepare the mixture. (2) Smelting: The weighed raw materials are placed in the smelting furnace, vacuumed, and then filled with high-purity argon as a protective gas. The furnace is heated and stirred evenly, and then a refining agent is added for refining. (3) Casting: Select a mold and preheat it, then cast the purified solution obtained in step (2) at 650-680℃; (4) After casting, the cast rod is homogenized and extruded, and then stretched and straightened to eliminate the internal stress generated during the extrusion process; (5) Solution treatment + aging treatment: Solution treatment at 520-540℃, heat preservation for 1-3h, water quenching; Aging treatment at 150-160℃, heat preservation for 4-8h.

[0012] Preferably, the heating temperature in step (2) is 700-720℃; the refining agent is a sodium chloride + potassium chloride composite refining agent, and the dosage is 0.2%-0.25% of the weight of the aluminum liquid.

[0013] Preferably, the mold in step (3) is a metal mold, and the preheating temperature is 200-260℃.

[0014] Preferably, the mold in step (3) is a sand mold, and the preheating temperature is 150-200℃.

[0015] Preferably, the homogenization process in step (4) includes: heating the casting rod to 455~465℃ at a heating rate of 38~42℃ / min, holding it at that temperature for 16~18h, and then naturally cooling it to room temperature.

[0016] Preferably, the extrusion process in step (4) includes: casting rod heating temperature: 520~530℃, die heating temperature: 480~500℃, extrusion cylinder heating temperature: 425~455℃, extrusion speed: 0.8~1.05m / min, and pipe extrusion molding under the condition that the profile outlet temperature is ≥470℃ and the extrusion ratio is 24~30.

[0017] Preferably, the stretching rate of the stretching straightening in step (4) is 0.5% to 2.0%.

[0018] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects: 1) The aluminum alloy profile prepared by the present invention can achieve a synergistic improvement in strength and conductivity, with tensile strength ≥200MPa and conductivity ≥58%IACS.

[0019] 2) The aluminum alloy conductors made using the materials and manufacturing process of this invention have a temperature rise value that is >10% lower than that of 6063-T6 aluminum alloy conductors under the same voltage level and current, which improves the current carrying capacity of switchgear and can provide a solution to the current carrying technology bottlenecks faced by switch products with increased capacity and compact design. At the same time, it can optimize the conductor wall thickness while meeting the current carrying capacity and other performance requirements of the products, reduce the overall manufacturing cost of conductors and busbar products, and increase the profit margin of the group's high-voltage switch products. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 The preparation process flow of this invention is as follows. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1 This embodiment provides a method for preparing a high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear, including the following steps: (1) Alloy composition ratio: According to the set chemical composition, weigh industrial pure aluminum, AlEr10 master alloy, AlLa10 master alloy, pure magnesium, pure zinc, Al 50Cu master alloy, Al B master alloy, Al Mn master alloy, etc. according to the stoichiometric ratio and prepare the alloy. The material composition is as follows: silicon (Si): 0.3%~0.6%, iron (Fe): ≤0.40%, copper (Cu) ≤0.10%, manganese (Mn) ≤0.03%, magnesium (Mg): 0.35%~0.8%, erbium (Er): 0.10%~0.15%, lanthanum (La): 0.08%~0.10%, chromium (Cr) ≤0.03%, boron (B) ≤0.06%, and other impurity elements total ≤0.10%.

[0024] (2) Smelting: The weighed raw materials are placed in the smelting furnace, vacuumed, and then filled with high-purity argon as a protective gas. The furnace is heated to 720°C and stirred evenly. A refining agent is added for refining treatment. The refining agent is a composite refining agent of sodium chloride and potassium chloride, and the amount used is 0.25% of the weight of the aluminum liquid.

[0025] (3) Casting: The mold is preheated to 240°C (metal mold), and the purified solution is cast at 680°C.

[0026] (4) Homogenization treatment: Heat the casting rod to 460°C at a heating rate of 40°C / min, hold for 16 hours and then let it cool naturally to room temperature.

[0027] (5) Extrusion process: The heating temperature of the cast rod is 530℃, the heating temperature of the die is 490℃, the heating temperature of the extrusion cylinder is 450℃, the extrusion speed is 1.1m / min, the outlet temperature of the profile is not less than 470℃, and the pipe is extruded under the condition of an extrusion ratio of 24.

[0028] (6) Stretch straightening: The stretching rate of stretch straightening is 1.3%, which is used to eliminate the internal stress generated during the extrusion process and improve the straightness and dimensional stability of the pipe.

[0029] (7) Solution treatment + aging treatment: solution treatment at 530℃, heat preservation for 2h, water quenching; aging treatment at 160℃, heat preservation for 7h.

[0030] Example 2 This embodiment provides a method for preparing a high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear, including the following steps: (1) Alloy composition ratio: According to the set chemical composition, weigh industrial pure aluminum, AlEr10 master alloy, AlLa10 master alloy, pure magnesium, pure zinc, Al 50Cu master alloy, Al B master alloy, Al Mn master alloy, etc. according to the stoichiometric ratio and prepare the alloy. The material composition is as follows: silicon (Si): 0.3%~0.6%, iron (Fe): ≤0.40%, copper (Cu) ≤0.10%, manganese (Mn) ≤0.03%, magnesium (Mg): 0.35%~0.8%, erbium (Er): 0.10%~0.15%, lanthanum (La): 0.08%~0.10%, chromium (Cr) ≤0.03%, boron (B) ≤0.06%, and other impurity elements total ≤0.10%.

[0031] (2) Smelting: The weighed raw materials are placed in the smelting furnace, vacuumed, and then filled with high-purity argon as a protective gas. The furnace is heated to 700°C and stirred evenly. A refining agent is added for refining treatment. The refining agent is a composite refining agent of sodium chloride and potassium chloride, and the amount used is 0.25% of the weight of the aluminum liquid.

[0032] (3) Casting: The mold is preheated to 180℃ (sand mold), and the purified solution is cast at 650-680℃.

[0033] (4) Homogenization treatment: Heat the casting rod to 465℃ at a heating rate of 42℃ / min, hold for 16 hours and then let it cool naturally to room temperature.

[0034] (5) Extrusion process: Casting rod heating temperature: 530℃, die heating temperature: 500℃, extrusion cylinder heating temperature: 55℃, extrusion speed: 0.8m / min, profile outlet temperature: not less than 470℃, pipe extrusion molding is carried out under the condition of extrusion ratio 30.

[0035] (6) Stretch straightening: The stretching rate of stretch straightening is 0.5%~2.0%, which is used to eliminate the internal stress generated during the extrusion process and improve the straightness and dimensional stability of the pipe.

[0036] (7) Solution treatment + aging treatment: solution treatment at 540℃, heat preservation for 1h, water quenching; aging treatment at 150℃, heat preservation for 8h.

[0037] Example 3 This embodiment provides a method for preparing a high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear, including the following steps: (1) Alloy composition ratio: According to the set chemical composition, weigh industrial pure aluminum, AlEr10 master alloy, AlLa10 master alloy, pure magnesium, pure zinc, Al 50Cu master alloy, Al B master alloy, Al Mn master alloy, etc. according to the stoichiometric ratio and prepare the alloy. The material composition is as follows: silicon (Si): 0.3%~0.6%, iron (Fe): ≤0.40%, copper (Cu) ≤0.10%, manganese (Mn) ≤0.03%, magnesium (Mg): 0.35%~0.8%, erbium (Er): 0.10%~0.15%, lanthanum (La): 0.08%~0.10%, chromium (Cr) ≤0.03%, boron (B) ≤0.06%, and other impurity elements total ≤0.10%.

[0038] (2) Smelting: The weighed raw materials are placed in the smelting furnace, vacuumed, and then filled with high-purity argon as a protective gas. The furnace is heated to 710°C and stirred evenly. A refining agent is added for refining. The refining agent is a sodium chloride + potassium chloride composite refining agent, and the amount is 0.22% of the weight of the aluminum liquid.

[0039] (3) Casting: The mold is preheated to 220℃ (metal mold), and the purified solution is cast at 650-680℃.

[0040] (4) Homogenization treatment: Heat the casting rod to 455℃ at a heating rate of 42℃ / min, hold for 18 hours and then let it cool naturally to room temperature.

[0041] (5) Extrusion process: Casting rod heating temperature: 520℃, die heating temperature: 480℃, extrusion cylinder heating temperature: 425℃, extrusion speed: 1.05m / min, profile outlet temperature: not less than 470℃, pipe extrusion forming under an extrusion ratio of 24.

[0042] (6) Stretch straightening: The stretching rate of stretch straightening is 0.5%, which is used to eliminate the internal stress generated during the extrusion process and improve the straightness and dimensional stability of the pipe.

[0043] (7) Solution treatment + aging treatment: Solution treatment at 520℃, heat preservation for 3h, water quenching; Aging treatment at 160℃, heat preservation for 4h.

[0044] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0045] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear, characterized in that, Listed by weight percentage, it includes the following ingredients: Si 0.3%~0.6%, Fe≤0.40%, Cu≤0.10%, Mn≤0.03%, Mg0.35%~0.8%, Er0.10%~0.15%, La0.08%~0.10%, Cr≤0.03%, B≤0.06%, and other impurity elements total ≤0.10%.

2. The method for preparing a high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear as described in claim 1, characterized in that, Includes the following steps: (1) The chemical composition of the high-strength and high-conductivity aluminum alloy material according to claim 1 is prepared by weighing industrial pure aluminum, AlEr10 master alloy, AlLa10 master alloy, pure magnesium, pure zinc, Al 50Cu master alloy, Al B master alloy and Al Mn master alloy according to the metric ratio. (2) Smelting: The weighed raw materials are placed in the smelting furnace, vacuumed, and then filled with high-purity argon as a protective gas. The furnace is heated and stirred evenly, and then a refining agent is added for refining. (3) Casting: Select a mold and preheat it, then cast the purified solution obtained in step (2) at 650-680℃; (4) After casting, the cast rod is homogenized and extruded, and then stretched and straightened to eliminate the internal stress generated during the extrusion process; (5) Solution treatment + aging treatment: Solution treatment at 520-540℃, heat preservation for 1-3h, water quenching; Aging treatment at 150-160℃, heat preservation for 4-8h.

3. The method for preparing a high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear according to claim 2, characterized in that, The heating temperature mentioned in step (2) is 700-720℃; The refining agent is a sodium chloride + potassium chloride composite refining agent, and the dosage is 0.2%-0.25% of the weight of the molten aluminum.

4. The method for preparing a high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear according to claim 2, characterized in that, The mold mentioned in step (3) is a metal mold, and the preheating temperature is 200-260℃.

5. The method for preparing a high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear according to claim 2, characterized in that, The mold mentioned in step (3) is a sand mold, and the preheating temperature is 150-200℃.

6. The method for preparing a high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear according to claim 2, characterized in that, The homogenization process described in step (4) includes: heating the casting rod to 455~465℃ at a heating rate of 38~42℃ / min, holding it at that temperature for 16~18h, and then naturally cooling it to room temperature.

7. The method for preparing a high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear according to claim 2, characterized in that, The extrusion process described in step (4) includes: heating temperature of the cast rod: 520~530℃, heating temperature of the die: 480~500℃, heating temperature of the extrusion cylinder: 425~455℃, extrusion speed: 0.8~1.05m / min, and extrusion forming of the pipe under the conditions of profile outlet temperature ≥470℃ and extrusion ratio 24~30.

8. The method for preparing a high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear according to claim 2, characterized in that, The stretching rate of the stretching straightening in step (4) is 0.5% to 2.0%.

9. The application of the high-strength, high-conductivity aluminum alloy conductor material for high-voltage switchgear as described in claim 1 in the bus conductors of 126-1100kV switchgear products.

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