Low-creep heat-resistant aluminum alloy wire and preparation method thereof

Abstract

The present application belongs to the technical field of aluminum alloy conductor, and particularly relates to a low-creep heat-resistant aluminum alloy conductor and a preparation method thereof. The product of the present application is a novel capacity-increased conductor with high electrical conductivity, high temperature resistance, high strength and low creep, and has the characteristics of low transmission line loss and high operation reliability. After the conductor is treated at high temperature and under large tension, the overall plastic creep elongation of the conductor is eliminated, the influence of the plastic creep elongation of the conductor on stringing and operation is avoided, the designed value of conductor sag at the initial stage of erection is consistent with the actual value. In the process of stringing and operation, the temperature reduction method is no longer used for compensation, the designed value of conductor sag is consistent with the actual value, and the safety hazards and cost increase caused by inaccurate estimated elongation are avoided.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy conductor technology, specifically relating to a low-creep heat-resistant aluminum alloy conductor and its preparation method. Background Technology

[0002] With the continuous development of power construction and the increasing transmission capacity of power transmission lines, heat-resistant aluminum alloy conductors with 60% IACS conductivity are commonly used in the construction of overhead transmission lines to achieve high-capacity power transmission and save on transmission corridor space. After installation, these 60% IACS conductivity heat-resistant aluminum alloy conductors, under long-term stress, will undergo not only elastic elongation but also plastic elongation and creep elongation, collectively referred to as plastic-creep elongation. Plastic-creep elongation causes permanent deformation of the conductor; that is, these two parts of elongation do not disappear after the tension is removed. It is related to the magnitude of the tension and the duration of its effect. During operation, with changes in conductor tension and the passage of time, this elongation gradually develops, eventually stabilizing after 5-10 years. The presence of plastic-creep elongation increases the conductor length within the span, thus permanently increasing the sag, reducing the distance between the conductor and the ground and objects being crossed, and endangering the safe operation of the line. Therefore, when constructing new overhead power lines, it is essential to compensate for the plastic creep elongation of the overhead conductors to prevent increased sag due to plastic creep elongation after long-term operation. Due to a lack of experience and theoretical basis, estimating conductor elongation during line design has become increasingly difficult. To address the issue of poor consistency between the design and actual values ​​of sag for heat-resistant aluminum alloy conductors with 60% IACS conductivity caused by factors such as plastic creep elongation, design standards often employ a cooling method to compensate for the increase in sag caused by both plastic and progressive creep elongation of the conductors. Summary of the Invention

[0003] The existing technology has the following drawbacks:

[0004] The use of heat-resistant aluminum alloy conductors with a conductivity of 60% IACS in high-capacity overhead transmission lines is problematic because the conductivity of the heat-resistant aluminum alloy material at 20℃ is only 60% IACS, resulting in high AC and DC resistance of the conductors and large power loss in the lines during high-temperature operation. At the same time, the tensile strength of the heat-resistant aluminum alloy material with a conductivity of 60% IACS is only 160MPa, which is slightly lower than that of steel-core heat-resistant aluminum alloy stranded wires made of galvanized steel core with a strength of 1310MPa, making it unsuitable for the safe and stable operation of transmission lines under conditions of strong winds and heavy icing.

[0005] As conductor structures become increasingly complex, estimating conductor creep during line design becomes more difficult. If the conductor cooling value used during actual line erection is too high, the initial stress of the line will also be higher. The line will operate under high stress in its initial stages, placing higher demands on conductors, hardware, and towers, as well as on vibration damping. Furthermore, excessive conductor stress in the initial stages of line erection may lead to hidden overstrength exceeding of tower strength limits. If strong winds, icing, or other heavy load events occur at this time, the maximum operating load of the conductor may exceed the limits specified in the design code, posing a safety hazard. Conversely, if the conductor cooling value is too low, long-term line operation will increase the length of the conductor within the span, causing excessive sag and insufficient distance to the ground and objects crossed, failing to meet safety distance requirements.

[0006] To address the shortcomings of existing technologies, this invention provides a low-creep heat-resistant aluminum alloy conductor and its manufacturing process. This product is a new type of capacity-enhancing conductor that combines high conductivity, high temperature resistance, high strength, and low creep. It features low transmission line loss and high operational reliability. At the same time, it eliminates the plastic creep elongation of the conductor, eliminating the need for cooling compensation during line erection and operation. The design value of the conductor sag matches the actual value well, avoiding safety hazards and increased costs caused by inaccurate estimation of plastic creep elongation.

[0007] This invention provides a method for preparing low-creep heat-resistant aluminum alloy wires, comprising the following steps:

[0008] S11: A heat-resistant aluminum alloy rod is prepared by continuous casting and rolling. The heat-resistant aluminum alloy rod is composed of the following components by weight fraction: 0.03-0.08 wt% Si, 0.15-0.30 wt% Fe, 0.50-0.60 wt% Zr, 0.03-0.05 wt% Mg, 0.01-0.02 wt% Cu, 0.08-0.24 wt% La, the sum of Cr, Mn, V and Ti is less than 0.003 wt%, and the remainder is Al and other unavoidable impurities.

[0009] S12: The heat-resistant aluminum alloy rod is heat-treated and then drawn into wire to obtain heat-resistant aluminum alloy wire;

[0010] S13: The heat-resistant aluminum alloy wire and the galvanized steel wire are concentrically stranded to obtain a stranded conductor;

[0011] S14: The stranded wire is subjected to plastic creep elongation elimination treatment and oxidation corrosion resistance treatment to obtain the low creep heat-resistant aluminum alloy wire; the low creep heat-resistant aluminum alloy wire includes an inner reinforcing core layer and an outer conductive layer wrapped around the inner reinforcing core layer; the inner reinforcing core layer is composed of 7 or 19 galvanized steel wires; the outer conductive layer is composed of several heat-resistant aluminum alloy wires.

[0012] This method improves the conductivity and tensile strength of heat-resistant aluminum alloy materials, reduces power transmission losses in overhead transmission lines, and enhances the safety and reliability of the lines.

[0013] Preferably, the continuous casting and rolling method includes the following steps:

[0014] S21: After melting aluminum ingots, AlB8 master alloy is added for boronizing treatment to obtain aluminum boride liquid;

[0015] S22: The aluminum boride liquid is refined once and then alloyed with aluminum alloy material to obtain alloy aluminum liquid; the aluminum alloy material is aluminum zirconium, aluminum iron and aluminum rare earth.

[0016] S23: After secondary refining of the alloy aluminum liquid, degassing, double-stage filtration, and online wire feeding are performed to obtain aluminum liquid to be cast.

[0017] S24: The molten aluminum to be cast is cast and rolled to complete the continuous casting and rolling method.

[0018] Preferably, in step S21, the mass ratio of AlB8 master alloy to aluminum ingot is 1-3:1000.

[0019] Preferably, in step S22, the refining method is as follows: under argon conditions, add granular refining agent and let stand for 55-65 minutes.

[0020] Preferably, in step S23, the secondary refining method is as follows: under argon conditions, add a sodium-removing refining agent and refine at 800-830℃ for 40-50 minutes, then remove the slag.

[0021] Preferably, in step S23, the online fiber feeding speed is 0.5-1.6 m / min.

[0022] Furthermore, the online wire feeding method includes the following steps: directly processing the aluminum-titanium-boron alloy into wire, loading the wire into the wire storage wheel in the wire feeder, the wire storage wheel being driven by a motor to rotate, and feeding the wire into the molten aluminum in the casting trough to a suitable depth in the molten aluminum, the wire is fed into the molten aluminum and interacts with the molten aluminum as it melts, and the composition is fine-tuned, wherein TiB2 provides nucleation sites.

[0023] Preferably, in step S24, the casting temperature is 678-692℃ and the casting speed is 6.2-6.7t / h.

[0024] Preferably, in step S24, the cooling water temperature during casting is 21-30℃, and the billet exit temperature is 460-485℃.

[0025] Preferably, in step S24, the rolling conditions are: the temperature of the initial rolling is 430-450℃, the temperature of the final rolling is 200-300℃, and after the final rolling is completed, the temperature is immediately cooled down to 80-120℃ by water cooling.

[0026] Specifically, by focusing on controlling the purity of aluminum ingots and sensitive impurity elements, the electrical conductivity and mechanical properties of the material matrix are improved. High-purity aluminum ingots of 99.85% or higher are used to melt the aluminum liquid, ensuring that the content of impurity elements in the material is within the required range.

[0027] Preferably, in step S12, the heat treatment method is to raise the temperature to 430-434℃ in 3-5 hours and hold it at that temperature for 124-132 hours.

[0028] Preferably, in step S12, the wire drawing method is as follows: the heat-treated heat-resistant aluminum alloy rod is subjected to 10-12 cold drawing passes, the elongation coefficient of the last 3 cold drawing passes increases sequentially, and the elongation coefficient ranges from 1.24 to 1.34; the elongation coefficient of the remaining cold drawing passes is 1.15 to 1.20.

[0029] Specifically, when drawing heat-resistant aluminum alloy rods, the desired result is a small-diameter, high-conductivity, high-strength heat-resistant aluminum alloy wire. The die inner diameter is designed as follows: Except for the last three dies, the cold-drawing elongation coefficient of the remaining dies is designed to be 1.15-1.20, and uniformly consistent; the elongation coefficient of the last three dies is designed to be 1.24-1.34, and increases in a stepped manner; the elongation coefficient is defined as k = R. 前 2 / R 后 2 , where R 前 R is the diameter before entering the mold. 后 This refers to the diameter after exiting the die. The elongation coefficient for cold drawing of the dies other than the last three is designed within this range to suppress the abnormal loss of conductivity of the high-conductivity, high-strength, heat-resistant aluminum alloy wire due to frequent large plastic deformation. The elongation coefficient for the last three dies is also designed within this range to control the resistivity of the semi-finished single wire relatively stably and at a low potential, maximizing the tensile strength and heat resistance of the high-conductivity, high-strength, heat-resistant aluminum alloy wire. Finally, the wire is drawn to the target small-diameter single wire through 10-12 dies. The tensile strength, conductivity, elongation, and heat resistance of the target small-diameter high-conductivity, high-strength, heat-resistant aluminum alloy wire can meet the corresponding requirements for wire drawing in Table 1.

[0030] In step S13, during concentric stranding, the stranding method is the same as that of ordinary conductors. The obtained heat-resistant aluminum alloy wire and galvanized steel core are concentrically stranded on a multi-segment frame stranding machine to prepare a high-conductivity heat-resistant aluminum alloy conductor (stranded conductor). This ensures that the tension of each single wire reel is uniform and that the high-conductivity heat-resistant aluminum alloy conductor does not become loose or serpentine during the stranding process.

[0031] Preferably, in step S14, the method for eliminating plastic creep elongation is as follows: preheat the stranded wire to 320-340℃ for 17-21s and then keep it at 320-340℃ for 11-14s.

[0032] The main purpose of using a bipolar high-temperature heat treatment method combining medium and high frequency heating furnaces is to solve the problem of poor thermal permeability of large-diameter wires. The diameter of the conductors generally ranges from 10-55mm. If only a medium-frequency induction heating furnace is used for high-temperature heat treatment of the conductors, large-diameter conductors (≥30mm in diameter) are prone to uneven radial heating when the production speed is fast. This affects the consistency of the elimination of plastic creep elongation from the inside to the outside of the conductor. By using a combination of medium-frequency and high-frequency heating furnaces for high-temperature heat treatment, the conductors are preheated to 330±10℃ in a 4.2m long medium-frequency induction furnace. The heat treatment time for any part of the conductor in the medium-frequency induction furnace is 17-21 seconds, achieving both heating and a certain duration of heat preservation. The conductors are then held at 330±10℃ in a 2.8m long high-frequency induction furnace. The heating and holding time for any part of the conductor in the high-frequency induction furnace is 11-14 seconds, achieving rapid heating and sufficient heat preservation. This ensures the uniform elimination of plastic creep elongation in all parts of the conductor and avoids the low efficiency caused by poor heat penetration and slow production speed of single-furnace heating treatment.

[0033] Preferably, in step S14, the method for oxidation and corrosion resistance treatment is as follows: spraying an anti-oxidant onto the stranded wire after the plastic creep elimination treatment; the anti-oxidant is composed of 10-14% aluminum rust inhibitor and 86-90% diluent by mass fraction.

[0034] Furthermore, the spraying is performed using a vaporization spraying machine, and the pressure for spraying the antioxidant is 145-155 kPa.

[0035] Specifically, the conductor enters the vaporization spraying system via a vaporization spraying machine. The purpose of this system is to address the poor oxidation and corrosion resistance of the conductor after heat treatment. After high-temperature heat treatment, the oil film attached to the high-conductivity, high-strength, heat-resistant aluminum alloy wire during the drawing process evaporates, destroying the oil film's surface corrosion protection. Without oxidation and corrosion resistance treatment, the conductor will undergo oxidation and corrosion after a period of storage or operation, shortening its service life.

[0036] The working principle of this vaporization spraying system is as follows: An air compressor drives high-pressure gas, which propels the antioxidant in the "reagent storage chamber" through a 360° annular nozzle in the vaporization sprayer onto the passing wire. The structure of the annular nozzle is as follows: Figure 5As shown, the number of nozzles is 40-60; excess anti-oxidant that slips off the sprayed wires flows into the reagent recovery chamber, and then flows into the reagent storage chamber via gas drive for recycling, thus avoiding material waste and environmental pollution.

[0037] The present invention also provides a low-creep heat-resistant aluminum alloy wire prepared by the above preparation method.

[0038] Preferably, when the internal reinforcing core layer consists of 7 galvanized steel wires, the internal reinforcing core layer is made by concentrically stranding 6 galvanized steel wires with a layer diameter ratio of 16-26 around 1 galvanized steel wire.

[0039] Preferably, when the internal reinforcing core layer consists of 19 galvanized steel wires, the internal reinforcing core layer is prepared by concentrically stranding 6 galvanized steel wires with a layer diameter ratio of 16-26 around 1 galvanized steel wire, and then concentrically stranding 12 galvanized steel wires with a layer diameter ratio of 14-22.

[0040] Furthermore, the stranding direction of 12 layers is opposite to that of the adjacent high-conductivity, high-strength, heat-resistant aluminum alloy wire layers, while the stranding direction of the remaining layers meets the requirement that the stranding directions of adjacent layers are opposite.

[0041] Preferably, when the number of outer conductive layers is not less than 2, the outermost layer is stranded in the right direction and the pitch ratio of this strand is 10-12, while the remaining heat-resistant aluminum alloy wire layers are arranged in the opposite direction and the pitch ratio is 10-16.

[0042] Preferably, when the number of outer conductive layers is 1, the strand diameter ratio is 10-12, and the stranding direction is right-handed.

[0043] Preferably, the galvanized steel wire has a circular cross-section, a tensile strength ≥2200MPa, and a coefficient of linear expansion of 11.5*10. -6 / ℃, density 7.78kg / dm 3 .

[0044] Preferably, the heat-resistant aluminum alloy wire has a circular cross-section, tensile strength ≥205MPa, electrical conductivity ≥62.3% IACS, heat resistance (360℃, 1h) ≥92%, elongation ≥4.4%, and density 2.703kg / dm³. 3 .

[0045] The technical solution of the present invention has the following advantages compared with the prior art:

[0046] 1) After the conductor is treated with high temperature and high tension, the overall plastic creep elongation of the conductor is eliminated, avoiding the influence of plastic creep elongation of the conductor during the stringing and operation process. This ensures that the design value of the conductor sag in the early stage of stringing is consistent with the actual value, and the cooling method is no longer needed to compensate for the plastic creep elongation of the overhead conductor, thus avoiding line safety problems caused by inaccurate estimation of elongation.

[0047] 2) Compared with the traditional 60% IACS heat-resistant aluminum alloy wire, the 62.3% IACS heat-resistant aluminum alloy wire has the following characteristics: ① The conductivity is increased by 2.3% IACS, and the transmission line loss can be reduced by about 3.8%, realizing large-capacity, low-loss power transmission. This type of new capacity-enhancing conductor is not only suitable for capacity expansion and renovation of old lines, but also for the construction of new transmission lines for new energy sources; ② The tensile strength is increased from 160MPa to over 205MPa, and the short-term heat resistance temperature is increased by 360℃. The heat resistance can ensure that the conductor's load-bearing capacity is not reduced after high-temperature and high-tension treatment compared to before treatment.

[0048] This invention provides a low-creep heat-resistant aluminum alloy conductor and its manufacturing process, overcoming the following problems: ① Poor conductivity of existing heat-resistant conductors, high AC and DC resistance during high-temperature operation, large power loss in the line, and poor load-bearing capacity; ② Difficulty in estimating conductor elongation during line design, excessive elongation may cause the maximum operating load of the conductor to exceed the limit value specified in the design specifications, leading to safety hazards such as conductor breakage, tower collapse, and pole breakage; excessive sag due to insufficient elongation leads to safety problems such as insufficient distance to the ground and crossing objects.

[0049] This product is a new type of capacity-enhancing conductor that combines high conductivity, high temperature resistance, high strength, and low creep. It features low transmission line loss and high operational reliability. At the same time, it eliminates the plastic creep elongation of the conductor, eliminating the need for cooling compensation during line erection and operation. The design value and actual value of the conductor sag are well matched, avoiding safety hazards and increased costs caused by inaccurate elongation estimates. Attached Figure Description

[0050] Figure 1 This is a typical structural diagram of a low-creep heat-resistant aluminum alloy conductor;

[0051] Figure 2 This is a typical structural diagram of a heat-resistant wire with a conventional 60% IACS conductivity.

[0052] Figure 3 Process route diagram for low creep heat-resistant aluminum alloy conductors;

[0053] Figure 4 Diagram of the system for eliminating creep and corrosion resistance treatment of plastics;

[0054] Figure 5 This is a schematic diagram of a 360° annular nozzle in a vaporization spraying machine.

[0055] Explanation of reference numerals in the attached diagram: 1-Electrical controller, 2-Medium frequency heating furnace, 3-High frequency heating furnace, 4-Constant tension controller, 5-High tension wire feeding frame, 6-Wire, 7-Double wheel drive wheel, 8-Air compressor, 9-Reagent storage chamber, 10-Vaporization sprayer, 11-Reagent recovery chamber, 12-Wire take-up frame, 13-360° ring frame, 14-Reagent vaporization nozzle. Detailed Implementation

[0056] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0057] Example 1

[0058] A low-creep, heat-resistant aluminum alloy conductor, such as Figure 1 As shown, the low-creep heat-resistant aluminum alloy wire includes an inner reinforcing core layer and an outer conductive layer wrapped around the inner reinforcing core layer.

[0059] The internal reinforcing core layer consists of 7 galvanized steel wires. This core layer is made by concentrically stranding 6 galvanized steel wires with a pitch ratio of 16-26 around one galvanized steel wire, with the stranding direction opposite to that of the adjacent high-conductivity, high-strength, heat-resistant aluminum alloy wire layer. The galvanized steel wire has a circular cross-section, a tensile strength ≥2200MPa, and a coefficient of linear expansion of 11.5*10. -6 / ℃, density 7.78kg / dm 3 .

[0060] The outer conductive layer consists of several heat-resistant aluminum alloy wires. These wires have a circular cross-section, tensile strength ≥205MPa, conductivity ≥62.3% IACS, heat resistance (360℃, 1h) ≥92%, elongation ≥4.4%, and density 2.703kg / dm³. 3 The number of outer conductive layers is 2, the outermost layer is stranded in the right direction, and the pitch ratio of this strand is 10-12. The remaining heat-resistant aluminum alloy wire layers are stranded in the opposite direction and have a pitch ratio of 10-16.

[0061] Example 2

[0062] A low-creep heat-resistant aluminum alloy wire, comprising an inner reinforcing core layer and an outer conductive layer wrapped around the inner reinforcing core layer;

[0063] The internal reinforcing core layer consists of 19 galvanized steel wires. This core layer is constructed by concentrically stranding one galvanized steel wire with six galvanized steel wires having a ply ratio of 16-26, followed by concentrically stranding another 12 galvanized steel wires with a ply ratio of 14-22. The stranding direction of these 12 strands is opposite to that of the adjacent high-conductivity, high-strength, heat-resistant aluminum alloy wire layers, while the stranding direction of the remaining layers conforms to the requirement of opposite stranding directions between adjacent layers. The galvanized steel wire has a circular cross-section, a tensile strength ≥2200MPa, and a coefficient of linear expansion of 11.5*10. -6 / ℃, density 7.78kg / dm 3 .

[0064] The outer conductive layer consists of several heat-resistant aluminum alloy wires. These wires have a circular cross-section, tensile strength ≥205MPa, conductivity ≥62.3% IACS, heat resistance (360℃, 1h) ≥92%, elongation ≥4.4%, and density 2.703kg / dm³. 3 The number of outer conductive layers is 1, the strand diameter ratio is 10-12, and the stranding direction is right-handed.

[0065] Example 3: Preparation of heat-resistant aluminum alloy wire

[0066] ① High-purity aluminum ingots are melted and boronized in a furnace. 2 kg of AlB8 master alloy is added to the furnace for boronizing at a rate of 2 kg per ton of molten aluminum to completely eliminate V and Ti elements and reduce their impact on the conductivity of the metal material.

[0067] ② Inject granular refining agent and perform a first refining with argon gas. Let it stand for 55-65 minutes. Due to its granular shape, the granular refining agent can prolong its reaction time in molten aluminum and has a good degassing and impurity removal effect.

[0068] ③ By adding materials such as aluminum zirconium, aluminum iron, and aluminum rare earth, the aluminum liquid is alloyed so that the chemical composition of the aluminum liquid finally reaches the required range of each element.

[0069] ④ After alloying, a second refining process is carried out using a sodium removal refining agent and argon gas, followed by slag removal after settling. During the second refining, a sodium removal refining agent is used to eliminate sodium ions in the aluminum melt. Sodium easily forms low-melting-point compounds, which can cause structural defects during subsequent annealing and affect the conductivity of the metal material. Therefore, using a sodium removal refining agent during the second refining process can effectively ensure the conductivity of the material.

[0070] ⑤ After blowing in the sodium removal refining agent, simmer the furnace for 40-50 minutes to allow the sodium removal refining agent to fully react with the impurities in the molten aluminum. The refining temperature is 800-830℃, and the settling time is 40-50 minutes. The secondary refining can remove the impurities generated during the alloying process and the sodium ions in the melt, further purifying the molten aluminum.

[0071] ⑥ The molten aluminum is poured into a holding furnace, and then degassed and filtered in a degassing box and a filter box.

[0072] ⑦ An online feeding step of aluminum boron wire was added to the flow channel, with a speed of (0.5-1.6) m / min. Its main functions are: a) to further reduce the content of Cr, Mn, V and Ti elements in the molten aluminum and improve the conductivity of the material; b) to react with zirconium elements in the molten aluminum to precipitate them, change the form of zirconium elements, improve the conductivity of the material, and at the same time achieve the purpose of refining the grains.

[0073] ⑧ The molten aluminum is continuously cast to obtain a heat-resistant aluminum alloy wire; wherein the casting temperature is 678-692℃, the casting speed is 6.2-6.7t / h, the cooling water temperature is 21-30℃, and the billet exit temperature is 460-485℃.

[0074] Example 4: Preparation of low-creep heat-resistant aluminum alloy wire

[0075] 1) Heat-treated heat-resistant aluminum alloy rods are then drawn to obtain heat-resistant aluminum alloy wires;

[0076] The high conductivity, high strength, and heat resistance of the heat-treated aluminum alloy rod can meet the requirements of the corresponding heat treatment items in Table 1.

[0077] Table 1 Product Performance of Each Process

[0078]

[0079] The heat-treated heat-resistant aluminum alloy rod was cold-drawn 10 times, and its elongation coefficient is shown in Table 2.

[0080] Table 2. Elongation coefficient design and mold dimensions (taking 3.60mm as an example)

[0081]

[0082] 2) The heat-resistant aluminum alloy wire and the galvanized steel wire are concentrically stranded to obtain a stranded conductor;

[0083] 3) The stranded wire is subjected to plastic creep elimination treatment and oxidation corrosion resistance treatment to obtain the low creep heat-resistant aluminum alloy wire.

[0084] The obtained stranded wire (hereinafter referred to as the wire) is subjected to plastic creep elimination treatment and oxidation corrosion resistance treatment. The plastic creep elimination treatment and oxidation corrosion resistance treatment device is as follows: Figure 4 As shown.

[0085] The device includes a high-tension pay-off frame 5, a medium-frequency heating furnace 2, a high-frequency heating furnace 3, a tension control system, a vaporization spraying system, and a take-up frame 12. The tension control system consists of a dual-wheel drive wheel 7 and a constant tension controller 4. The vaporization spraying system consists of an air compressor 8, a reagent storage chamber 9, a vaporization spraying machine 10, and a reagent recovery chamber 11. The specific working sequence for the plastic creep elimination treatment and the oxidation corrosion resistance treatment is as follows:

[0086] (1) The conductor is released at a constant speed through the wire-laying frame;

[0087] (2) The wire released from step (1) undergoes bipolar high-temperature heat treatment in medium-frequency heating furnace 2 and high-frequency heating furnace 3, and then enters the double-wheel drive wheel 7. The wire is wrapped around the double-wheel drive wheel 7 5-6 times. The constant tension controller 4 drives the double-wheel drive wheel 7 to rotate and realize speed control. The constant tension controller 4, the double-wheel drive wheel 7 and the high-tension wire feeding frame 5 work together to apply high tension to the wire.

[0088] (3) The wire processed in step (2) enters the vaporization spraying machine 10 for anti-oxidation reagent spraying; the working principle of this vaporization spraying system is as follows: high-pressure gas is driven by an air compressor, and the high-pressure gas sprays the anti-oxidant in the reagent storage chamber 9 onto the passing wire through the reagent vaporization nozzle 14 on the 360° annular frame 13 in the vaporization spraying machine 10. The structure of the annular nozzle is as follows. Figure 5 As shown, there are 50 nozzles; excess anti-oxidant that slips off the sprayed wires flows into the reagent recovery chamber 11, and then flows into the reagent storage chamber 9 via gas drive for recycling, thus avoiding material waste and environmental pollution.

[0089] (4) The wire processed in step (3) enters the take-up frame 12 for take-up and packaging to obtain the product.

[0090] The constant tension device drives the dual-wheel drive wheel 7 to rotate, so as to achieve stable and controllable wire movement speed in the system. The production speed is 12-15m / min, and a large tension is applied to the wire. When the aluminum cross-section in the wire is large, the wire plastic creep elongation is large, and a larger proportion of tension is required to eliminate it. Conversely, a slightly smaller tension can be used. The specific large tension values ​​are shown in Table 3.

[0091] Table 3 Output tension of the constant tension system

[0092]

[0093] Note: 1. Aluminum-to-steel cross-sectional area ratio m: The ratio of the cross-sectional area of ​​all high-conductivity, high-strength, heat-resistant aluminum alloy wires to the cross-sectional area of ​​all galvanized steel wires in the conductor; 2. RTS: Rated breaking strength of the conductor, kN.

[0094] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a low-creep heat-resistant aluminum alloy conductor, characterized in that, Includes the following steps: S11: A heat-resistant aluminum alloy rod is prepared by continuous casting and rolling. The heat-resistant aluminum alloy rod is composed of the following components by weight fraction: 0.03-0.08 wt% Si, 0.15-0.30 wt% Fe, 0.50-0.60 wt% Zr, 0.03-0.05 wt% Mg, 0.01-0.02 wt% Cu, 0.08-0.24 wt% La, the sum of Cr, Mn, V and Ti is less than 0.003 wt%, and the remainder is Al and other unavoidable impurities. The continuous casting and rolling method includes the following steps: S21: After melting aluminum ingots, AlB8 master alloy is added for boronizing treatment to obtain aluminum boride liquid; S22: The aluminum boride liquid is refined once and then alloyed with aluminum alloy material to obtain alloy aluminum liquid; the aluminum alloy material is aluminum zirconium, aluminum iron and aluminum rare earth. S23: After secondary refining of the alloy aluminum liquid, degassing, double-stage filtration, and online wire feeding are performed to obtain aluminum liquid to be cast. S24: The molten aluminum to be cast is cast and rolled to complete the continuous casting and rolling method; in step S23, the online wire feeding speed is 0.5-1.6 m / min; in step S24, the casting temperature is 678-692℃, and the casting speed is 6.2-6.7 t / h; the rolling conditions are: the inlet rolling temperature is 430-450℃, and the final rolling temperature is 200-300℃; after the final rolling is completed, the temperature is immediately cooled to 80-120℃ by water cooling. S12: The heat-resistant aluminum alloy rod is heat-treated and then drawn into wire to obtain heat-resistant aluminum alloy wire; S13: The heat-resistant aluminum alloy wire and the galvanized steel wire are concentrically stranded to obtain a stranded conductor; S14: The stranded wire is subjected to a creep eliminator treatment and an oxidation corrosion resistant treatment to obtain the low creep heat-resistant aluminum alloy wire; the low creep heat-resistant aluminum alloy wire includes an inner reinforcing core layer and an outer conductive layer wrapped around the inner reinforcing core layer; the inner reinforcing core layer is composed of 7 or 19 galvanized steel wires; the outer conductive layer is composed of several heat-resistant aluminum alloy wires; in step S14, the creep eliminator treatment is performed by preheating the stranded wire at 320-340℃ for 17-21 seconds and then holding it at 320-340℃ for 11-14 seconds.

2. The preparation method according to claim 1, characterized in that, In step S12, the heat treatment method is to raise the temperature to 430-434℃ in 3-5 hours and hold it at that temperature for 124-132 hours.

3. The preparation method according to claim 1, characterized in that, In step S12, the wire drawing method is as follows: the heat-treated heat-resistant aluminum alloy rod is subjected to 10-12 cold drawing passes, and the elongation coefficient of the last 3 cold drawing passes increases sequentially, with the elongation coefficient ranging from 1.24 to 1.34; the elongation coefficient of the remaining cold drawing passes is 1.15 to 1.

20.

4. The preparation method according to claim 1, characterized in that, In step S14, the method for oxidation and corrosion resistance treatment is as follows: spraying an anti-oxidant onto the stranded wire after the plastic creep elimination treatment; the anti-oxidant is composed of 10-14% aluminum rust inhibitor and 86-90% diluent by mass fraction.

5. A low-creep heat-resistant aluminum alloy wire prepared by the preparation method according to any one of claims 1-4.

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