Energy-saving and efficient method for preparing high-performance aluminum alloy conductor

Abstract

The invention discloses an energy-saving and efficient method for preparing a high-performance aluminum alloy conductor, and relates to the technical field of metal material processing. The component formula of the lead is Al-xSi-yMg-zCu-mRE-nB, wherein x is larger than or equal to 0.6 and smaller than or equal to 1.4, y is larger than or equal to 0.05 and smaller than or equal to 0.3, z is smaller than or equal to 0.1, m is larger than or equal to 0.01 and smaller than or equal to 0.1, n is larger than or equal to 0.04 and smaller than or equal to 0.12, and the preparation technological process comprises the steps of burdening, flame direct injection smelting, refining, synchronous water quenching pull casting, cold forming machining and aging annealing synchronous heat treatment. By optimizing the formula and adopting the process matched with the formula, the wire with high mechanical strength (greater than or equal to 120 MPa), high conductivity (greater than or equal to 62% IACS) and good plasticity (greater than or equal to 14%) can be prepared, and the preparation method is short in process flow, easy to operate, low in preparation cost, low in energy consumption, convenient to industrialize and wide in application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal material processing, and particularly relates to a method for preparing high-performance aluminum alloy wire with energy saving and high efficiency. BACKGROUND

[0002] Developing new aluminum alloy cables is of great significance in terms of power transmission, economic benefits, and environmental protection. It is not only a progress in material technology, but also an important choice to address resource challenges and promote sustainable development. Traditional pure aluminum cables have poor creep resistance and insufficient flexibility. Aluminum alloy cables significantly improve their overall performance by adding rare earth elements, magnesium, copper, or silicon to aluminum and using special compacting processes and annealing. Firstly, aluminum alloy cables have stronger mechanical properties than pure aluminum cables and are easier to install than copper cables. Aluminum alloy cables have excellent connection stability and creep resistance. For example, AA8000 series aluminum alloy cables have 300% creep resistance compared to pure aluminum, which can significantly reduce the loosening problem caused by thermal expansion and contraction, and reduce the risk of increased contact resistance and overheating. Aluminum alloy cables also have good corrosion resistance. The aluminum alloy surface forms a dense oxide film, and the addition of rare earth elements improves its corrosion resistance, especially its electrochemical corrosion resistance, which is better than that of pure aluminum and even better than that of copper in sulfur-containing environments such as tunnels.

[0003] The application of aluminum alloy cables can bring significant economic benefits. The application of aluminum alloy cables can effectively reduce the overall cost of power projects. The direct material cost is lower: the resource reserves of aluminum are large, and the price is much lower than that of copper. The purchase price of aluminum alloy cables is usually 15-60% lower than that of copper cables with the same electrical properties. The installation and transportation costs are more cost-effective, and the weight of aluminum alloy cables is lighter than that of copper cables, which makes transportation, handling and installation more convenient, saving 20-40% of installation costs, and requiring less support structure. From a whole life cycle perspective, aluminum alloy cables also have obvious cost advantages. Their corrosion resistance and creep resistance help reduce maintenance frequency and long-term operating costs, and are expected to have a service life of more than 40 years, comparable to or even better than copper cables.

[0004] Aluminum alloy wire is the core component of aluminum alloy cable, and its performance directly determines the transmission efficiency and the safety of service operation. The traditional preparation process of aluminum alloy wire mainly includes melting and alloying, casting and initial forming, hot working, cold working and deformation strengthening, aging treatment and annealing treatment. First, high-purity aluminum ingot (usually purity ≥ 99.7%) is selected as the basic raw material. In order to improve the specific performance, various intermediate alloys are added. The melting temperature is generally controlled at 720-750°C. Then it needs to be refined, usually using sodium-free refining agent and argon blowing to remove gas and impurities in the melt. In order to further purify the melt and refine the grains, ultrasonic treatment or filtration treatment (such as through ceramic filter plate) may also be used. The refined aluminum alloy liquid is poured into a mold and cast into an aluminum alloy ingot, or directly produced into an aluminum alloy rod through continuous casting and rolling process (initial rolling temperature is about 480-520°C, and final rolling temperature is about 250-300°C). The cast ingot or continuous casting blank usually needs to go through hot extrusion (heating temperature is about 410-450°C) or hot drawing (heating and then drawing) and other hot working processes for preliminary deformation and forming. Then cold drawing is carried out, which is the key step to improve the strength of the wire. It is mainly realized through cold drawing, and multiple passes of drawing are carried out at room temperature, with the diameter reduction rate of each pass usually controlled at 15-20%. In recent years, some severe plastic deformation techniques (such as continuous ECAE - equal channel angular extrusion) have also been used in in-line shape deformation heat treatment, aiming to further refine the grains and improve the strength. Then it enters the heat treatment process, which is crucial for regulating the final performance of the wire. The heat treatment includes aging treatment and annealing treatment. The aging heat treatment aims to precipitate strengthening phase from the supersaturated solid solution, such as single-stage aging (such as 270-340°C for 20-40 hours) or two-stage aging (such as 300°C for 25 hours, then quickly heated to 380-400°C for 40-80 hours). Annealing treatment is to anneal the finished wire (such as 330-370°C for 1-3 hours) to eliminate stress and stabilize the structure. The existing aluminum alloy wire preparation technology has the disadvantages of high production cost and long production process, which needs to be further improved. SUMMARY

[0005] In view of the above problems, the present application provides a method for preparing high-performance aluminum alloy wire with energy saving and high efficiency. The aluminum alloy wire prepared by the process of "flame direct melting → refining → synchronous water quenching and casting → cold forming processing → aging and annealing synchronous heat treatment" has high mechanical strength (≥120 MPa), high electrical conductivity (≥62% IACS) and sufficient plasticity (≥14%). The process is short, easy to operate, low in preparation cost and energy consumption, and easy to industrialize, with broad application prospects. The specific technical scheme is as follows: The application discloses a method for preparing high-performance aluminum alloy wires with energy saving and high efficiency. x Si- y Mg- z Cu- m RE- n B, coefficient x, y, z, m, n are mass percentages of Si, Mg, Cu and B in the alloy respectively, wherein 0.6<= x <=1.4, 0.05<= y <=0.3, z <=0.1, 0.01<= m <=0.1, 0.04<= n <=0.12; The method for preparing the high-performance aluminum alloy wires comprises the following steps: Step S1: batching Each raw material component is weighed according to a mass ratio; Step S2: flame direct injection smelting Each raw material component is placed in a smelting furnace and smelted by using flame direct injection; Step S3: refining A refining agent is added into the smelting furnace for refining, and then the refined melt is transferred into a buffer furnace, and the melt temperature in the buffer furnace is controlled to be 700-720 DEG C; The bottom of the buffer furnace is provided with an aluminum alloy wire rod forming die, the aluminum alloy wire rod forming die is provided with a through hole penetrating through the aluminum alloy wire rod forming die, the center line of the through hole is parallel to the bottom of the buffer furnace, one end of the through hole is connected with the melt in the buffer furnace, and the other end of the through hole leads to the outside of the buffer furnace; Step S4: synchronous water quenching and drawing The height difference between the melt surface in the buffer furnace and the center line of the through hole of the aluminum alloy wire rod forming die is controlled, the furnace temperature is controlled to be kept at 690-710 DEG C, then the opening of the through hole of the die is opened, the aluminum alloy liquid slowly flows out from one end of the through hole to the other end of the through hole by means of the pressure difference generated by the height difference of the liquid surface, the aluminum alloy liquid just flowing out is instantaneously and rapidly water quenched and cooled, the aluminum alloy liquid is rapidly cooled and condensed into a wire rod, the cooling end of the wire rod is wound on an automatic take-up machine while the wire rod is water quenched and cast, the rotating speed of the take-up machine is controlled, and the wire rod is slowly drawn out of the through hole of the die, thereby obtaining an aluminum alloy wire rod; The aluminum alloy melt drawn out of the die hole is instantaneously and rapidly water quenched and cooled, so that the composition of the aluminum alloy wire rod can be kept in a uniform distribution close to that of the aluminum alloy melt; Step S5: cold forming processing The aluminum alloy wire rod is cold-rolled and cold-drawn to obtain a hard-state (Y-state) aluminum alloy wire; The combined forming process of rolling first and then drawing can make the grain structure of the aluminum alloy conductor be fibrous and be distributed along the axial direction, thereby increasing the compactness, dislocation density and axial tensile strength of the aluminum alloy, and the drawing process can accurately control the outer dimension and surface smoothness of the conductor. Step S6: aging annealing synchronous heat treatment The hard-state aluminum alloy conductor is heated to 240-260 DEG C, the holding time is 6-24 h, and the furnace is cooled, thereby obtaining the high-performance aluminum alloy conductor. The aging annealing synchronous heat treatment process can simultaneously realize the aging purpose of precipitating the second phase and the annealing purpose of reducing the internal stress and defects of the alloy through one-step heat treatment.

[0006] Preferably, in step S1, the ingredients are as follows: low-iron industrial pure aluminum is weighed as the aluminum alloy base material according to the mass ratio, and Si, Mg, Cu, RE and B aluminum-based intermediate alloy or element are weighed as alloying agents.

[0007] The low-iron industrial pure aluminum has a Fe mass percentage of not more than 0.1%, the intermediate alloy is any component of Al-Si, Al-Mg, Al-Cu, Al-RE or Al-B or any component of aluminum-based ternary intermediate alloy, the Al-RE intermediate alloy can be one or more of Al-La, Al-Y, Al-Ce and Al-Er, and the element is Mg element; the industrial pure aluminum, aluminum-based intermediate alloy or element can be in the forms of block, particle, powder or profile.

[0008] Preferably, in step S2, the flame direct injection smelting is as follows: the low-iron aluminum ingot is placed in a smelting furnace, mixed gas of natural gas and air is introduced into the furnace, ignition, the high-temperature gas generated by the flame is directly sprayed to the surface of the material for heating, the material is completely melted after being heated to 700-720 DEG C and then being kept warm for 5-10 min, and then the alloying agents of Si, Mg, Cu, RE and B are sequentially added, each alloying agent is stirred for 3-5 min and is kept still for 10-15 min.

[0009] The cost of the natural gas used in the application is lower than that of electric energy.

[0010] Preferably, in step S3, the refining is as follows: the refining agent is added to the material after smelting in step S2, the material is stirred for 5-10 min, kept still for 10-15 min, and then slag is removed, and then the refined melt is transferred into a buffer furnace.

[0011] Preferably, in step S3, the refining agent is hexachloroethane (C2Cl6), and the addition amount of the hexachloroethane is 0.2-0.6% of the total mass of the alloy.

[0012] Preferably, in step S4, the diameter of the wire rod is 6-12 mm.

[0013] Preferably, in step S5, the cold rolling pass is ≥ 10 times, and the deformation is ≥ 85%; the cold drawing pass is ≥ 5 times, and the deformation is ≥ 15%.

[0014] The application further provides a high-performance aluminum alloy wire prepared by the method.

[0015] Compared with the prior art, the application has the following beneficial effects: 1. The application adopts a process method of ''flame direct injection smelting→refining→synchronous water quenching and drawing→cold forming processing→aging annealing synchronous heat treatment'' matched with the formula of Al-xSi-yMg-zCu-mRE-nB aluminum alloy, through mutual coordination between processes, under suitable process parameters, uniform distribution of fine precipitated phase is formed in the aluminum alloy wire matrix, the aluminum lattice system is purified, so that the strength of the aluminum alloy is improved while higher electrical conductivity is obtained.

[0016] 2. The combined effect of RE and B can adjust the second phase morphology, particle size and dispersity, and better refine the aluminum alloy grains; the cold forming process of the application adopts a combined forming process of cold rolling first and then drawing, the cold rolling can make the aluminum alloy wire grain structure present fibrous shape and be distributed along the axial orientation, thereby increasing the compactness of the aluminum alloy. The drawing process can accurately control the outer shape size and surface finish of the wire. The cold forming process of the application increases the dislocation density in the alloy and reduces the nucleation energy of the aluminum alloy and the second phase, so that the grain structure is significantly refined in the wire after the aging annealing synchronous heat treatment, thereby obtaining better mechanical properties.

[0017] 3. The application realizes the solid solution aging treatment of the aluminum alloy under the premise of simplifying the preparation process of the aluminum alloy wire rod, avoids the energy consumption in the solid solution aging process, and lays a good foundation for the subsequent annealing synchronous aging process. The application adopts a gas flame direct injection smelting method, directly sprays the high-temperature flame generated by gas combustion to the surface of the aluminum alloy, and controls the gas amount in real time according to the temperature feedback in the furnace, so that the thermal efficiency is higher than that of the traditional smelting method.

[0018] 4. Compared with the traditional process method, the application does not need to be cast into an aluminum ingot before preparing the aluminum alloy wire rod, the aluminum alloy wire rod does not need to be subjected to any heat treatment before processing and forming, and the processing and forming process does not need intermediate annealing, so that the process flow is short, the energy consumption is low, the production cost is low, the production efficiency is high, the tensile strength of the prepared aluminum alloy wire is ≥ 120 MPa, the elongation is ≥ 14%, the electrical conductivity is ≥ 62% IACS, and the aluminum alloy wire has excellent mechanical properties and electrical conductivity. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description.

[0020] Figure 1 Process flow chart for preparing the aluminum alloy conductor of the present application; Figure 2 Field emission scanning electron microscope image of the cross section of the aluminum alloy conductor prepared in Example 1 of the present application; Figure 3 Comparison chart of tensile strength and elongation of the aluminum alloy conductors prepared in Examples 1-9 and Comparative Examples 1-4 of the present application; Figure 4 Comparison chart of electrical conductivity of the aluminum alloy conductors prepared in Examples 1-9 and Comparative Examples 1-4 of the present application; Figure 5 Process schematic diagram of the synchronous water quenching and drawing of the aluminum alloy melt after the buffer furnace of the present application. DETAILED DESCRIPTION

[0021] The specific embodiments of the present application will be described in detail below, but it should be understood that the protection scope of the present application is not limited by the specific embodiments.

[0022] Example 1 The preparation process flow of the Al-1.2Si-0.2Mg-0.025Cu-0.02Er-0.08B aluminum alloy conductor is shown in Figure 1

[0023] Prepare the raw materials according to the mass percentage of each element in the Al-1.2Si-0.2Mg-0.025Cu-0.05Er-0.08B aluminum alloy conductor: this example is used to illustrate the influence of alloy composition on the performance of the conductor. The preparation steps of the conductor are as follows: Step S1: weighing, weigh 440.08 kg of industrial pure aluminum, 23.36 kg of Al-20Si intermediate alloy, 9.60 kg of Al-10Mg intermediate alloy, 0.24 kg of Al-50Cu intermediate alloy, 1.92 kg of Al-5Er intermediate alloy, 4.80 kg of Al-8B intermediate alloy, and 2.4 kg of hexachloroethane.

[0024] Step S2: flame direct injection smelting Put the low-iron aluminum ingot in step S1 into the pilot smelting furnace, pass mixed gas of natural gas and air into the furnace, heat the material by the flame generated by ignition, heat to 710 ℃ to melt the material, and then keep the temperature for 8 min. Add the alloying agents of Si, Mg, Cu, Er and B in turn, and stir for 4 min and stand for 12 min after adding each alloying agent.

[0025] Step S3: refining​ The hexachloroethane (C2Cl6) in step S1 is added into the smelting furnace, stirred for 8 min, and rested for 12 min before slagging, and then the outlet of the smelting furnace is opened to allow the melt to flow into the buffer furnace, and the temperature of the melt in the buffer furnace is controlled to 710 ℃ by a flame generated by natural gas and air combustion.

[0026] Step S4: synchronous water quenching and casting The melt obtained in S3 is released into the buffer furnace through the bottom outlet, as shown in Figure 5 The bottom of the buffer furnace is provided with an aluminum alloy wire rod forming die, the aluminum alloy wire rod forming die is provided with a through hole, the center line of the through hole is parallel to the bottom of the buffer furnace, one end of the through hole is connected with the melt in the buffer furnace, and the other end leads to the outside of the buffer furnace. After the melt enters the buffer furnace, the height difference between the liquid level in the buffer furnace and the center line of the die through hole is controlled within a certain range, and the furnace temperature is controlled to remain at 700 ℃, and then the die opening is opened, and the melt flows out from the die opening to form a wire rod with a diameter of 8 mm under the pressure difference generated by the height difference of the liquid level, and cold water is sprayed from the water cooling nozzle to cool the wire rod part just leaving to quickly cool it. At the same time of water quenching and casting, the cooling end of the wire rod is wound on the automatic take-up machine, and the rotating speed of the take-up machine is controlled to slowly pull out the wire rod from the die hole, so as to realize the purpose of synchronous water quenching and casting.

[0027] Step S5: cold forming processing The aluminum alloy rod obtained in step S4 is cold rolled and cold drawn, and the cold rolling pass is 12 times and the cold drawing pass is 6 times, so as to prepare the aluminum alloy wire rod in a hard state (Y state).

[0028] Step S6: aging annealing and synchronous heat treatment The aluminum alloy wire rod obtained in step S5 is subjected to aging annealing treatment, that is, the aluminum alloy wire rod is heated to 250 ℃, the holding time is 10 h, and the furnace is cooled, so as to prepare the aluminum alloy wire rod with excellent performance.

[0029] Figure 2 The field emission scanning electron microscope image of the cross section of the aluminum alloy wire rod prepared in this embodiment is shown in the figure, and a large number of nano-sized fine precipitated phases are formed in the aluminum alloy wire rod matrix, and the precipitated phases are uniformly distributed in the form of equiaxed particles or fine short rods. Such microstructure can purify the aluminum lattice system, so as to improve the strength of the aluminum alloy while obtaining high electrical conductivity and good plasticity.

[0030] Example 2 The aluminum alloy wire rod preparation process flow of Al-1.2Si-0.2Mg-0.025Cu-0.02Er-0.08B is shown in Figure 1 .

[0031] The raw materials are prepared according to the mass percentage of each element in the Al-1.2Si-0.2Mg-0.025Cu-0.02Er-0.08B aluminum alloy wire: this example is used to illustrate the influence of the preparation process on the performance of the conductor. The preparation steps of the conductor are as follows: Step S1: weighing, which is exactly the same as in Example 1.

[0032] Step S2: flame direct injection smelting The low-iron aluminum ingot in step S1 is placed in a pilot smelting furnace, a mixture of natural gas and air is introduced into the furnace, and the flame generated by ignition is used to heat the material. After the material is completely melted and the temperature is raised to 720 ℃, it is kept for 5 min, and then the alloying agents of Si, Mg, Cu, Er and B are added in sequence. Each alloying agent is stirred for 3 min and then kept for 10 min.

[0033] Step S3: refining C2Cl6 in step S1 is added to the smelting furnace, stirred for 5 min, kept for 10 min, and then slagged. Subsequently, the outlet at the bottom of the smelting furnace is opened, and the melt flows into the buffer furnace. The temperature of the melt in the buffer furnace is controlled to be 720 ℃ by the flame generated by the combustion of natural gas and air.

[0034] Step S4: synchronous water quenching and casting The melt obtained in S3 is released into the buffer furnace through the bottom outlet, as shown in Figure 5 The bottom of the buffer furnace is provided with an aluminum alloy wire rod forming mold, which is provided with a through hole. The center line of the through hole is parallel to the bottom of the buffer furnace, one end of the through hole is connected with the melt in the buffer furnace, and the other end leads to the outside of the buffer furnace. After the melt enters the buffer furnace, the height difference between the liquid level in the buffer furnace and the center line of the mold hole is controlled within a certain range, and the furnace temperature is controlled to be kept at 710 ℃. Subsequently, the mold opening is opened, and the aluminum water flows out from the mold opening to form a wire rod with a diameter of 6 mm by means of the pressure difference generated by the height difference of the liquid level. At the same time, cold water is sprayed from the water cooling nozzle to cool the wire rod just leaving the wire rod part, so as to quickly cool it. At the same time of water quenching and casting, the cooling end of the wire rod is wound on the automatic take-up machine, and the rotating speed of the take-up machine is controlled to make the wire rod slowly pulled out of the mold hole, so as to realize the purpose of synchronous water quenching and casting.

[0035] Step S5: cold forming processing The aluminum alloy rod obtained in step S4 is cold rolled and cold drawn, and the cold rolling pass is 14 times and the cold drawing pass is ≥8 times, so as to prepare the aluminum alloy wire in hard state (Y state).

[0036] Step S6: simultaneous heat treatment of aging and annealing The aluminum alloy wire obtained in step S5 is subjected to aging annealing treatment, i.e. the aluminum alloy wire is heated to 260 ℃, the holding time is 6 h, and the furnace is cooled, so that the aluminum alloy wire with excellent performance is prepared.

[0037] Example 3 The preparation process flow of the Al-1.2Si-0.2Mg-0.025Cu-0.02Er-0.08B aluminum alloy wire is shown in Figure 1 .

[0038] The raw materials of the Al-1.2Si-0.2Mg-0.025Cu-0.02Er-0.08B aluminum alloy wire are prepared according to the mass percentage of each element in the aluminum alloy wire. This example is used to illustrate the influence of the preparation process on the performance of the conductor. The preparation steps of the conductor are as follows: Step S1: weighing, which is exactly the same as in Example 1.

[0039] Step S2: flame direct injection smelting, the low-iron aluminum ingot in step S1 is placed in a pilot smelting furnace, a mixture of natural gas and air is introduced into the furnace, the flame generated by ignition heats the material, the temperature is raised to 700 ℃ to melt the material, and then the temperature is maintained for 10 min. The alloying agents of Si, Mg, Cu, Er and B are added in sequence, and each alloying agent is stirred for 5 min and then placed for 15 min.

[0040] Step S3: refining, C2Cl6 in step S1 is added to the smelting furnace, stirred for 10 min, and then placed for 15 min. The slag is removed, and then the outlet at the bottom of the smelting furnace is opened to allow the melt to flow into the buffer furnace. The temperature of the melt in the buffer furnace is controlled to 700 ℃ by the flame generated by the combustion of natural gas and air.

[0041] Step S4: synchronous water quenching and casting, the melt obtained in S3 is released through the bottom outlet into the buffer furnace, as shown in Figure 5 , the bottom of the buffer furnace is provided with an aluminum alloy rod forming mold, the aluminum alloy rod forming mold is provided with a through hole, the center line of the through hole is parallel to the bottom of the buffer furnace, one end of the through hole is connected with the melt in the buffer furnace, and the other end leads to the outside of the buffer furnace. After the melt enters the buffer furnace, the height difference between the liquid level in the buffer furnace and the center line of the mold hole is controlled within a certain range, and the furnace temperature is controlled to keep it at 690 ℃. Then the mold opening is opened, and the aluminum water flows out from the mold opening to form a rod with a diameter of 12 mm under the pressure difference generated by the height difference of the liquid level. At the same time, cold water is sprayed from the water cooling nozzle to quickly cool the just-exited rod part. At the same time of water quenching and casting, the cooling end of the rod is wound on the automatic take-up machine, and the rotating speed of the take-up machine is controlled to slowly pull out the rod from the mold hole, so as to realize the purpose of synchronous water quenching and casting.

[0042] Step S5: cold forming processing, the aluminum alloy rod obtained in step S4 is cold rolled and cold drawn, the cold rolling pass is 10 times, and the cold drawing pass is 5 times, so that the aluminum alloy conductor in a hard state (Y state) is prepared.

[0043] Step S6: aging annealing synchronous heat treatment, the aluminum alloy conductor obtained in step S5 is subjected to aging annealing treatment, that is, the aluminum alloy conductor is heated to 240 DEG C, the holding time is 24 h, and the furnace is cooled, so that the aluminum alloy conductor with excellent performance is prepared.

[0044] Example 4 The aluminum alloy conductor preparation process flow of Al-1.2Si-0.2Mg-0.025Cu-0.02Y-0.08B is shown in Figure 1 .

[0045] According to the mass percentage of each element in the Al-1.2Si-0.2Mg-0.025Cu-0.02Y-0.08B aluminum alloy, the raw materials are prepared: this example is used to illustrate the influence of alloy composition on the performance of the conductor. The preparation steps of the conductor are as follows: Step S1: batching, 440.08 kg of pure aluminum, 23.36 kg of Al-20Si intermediate alloy, 9.60 kg of Al-10Mg intermediate alloy, 0.24 kg of Al-50Cu intermediate alloy, 1.92 kg of Al-5Y intermediate alloy, 4.8 kg of Al-8B intermediate alloy, and 0.96 kg of hexachloroethane are weighed.

[0046] Step S2: flame direct injection smelting, the low-iron aluminum ingot in step S1 is placed in a pilot smelting furnace, a mixed gas of natural gas and air is introduced into the furnace, the flame generated by ignition heats the material, the temperature is raised to 720 DEG C, the material is completely melted, and then the temperature is kept for 5 min, and the alloying agents of Si, Mg, Cu, Y and B are added in turn, each alloying agent is stirred for 3 min and kept for 10 min.

[0047] The other preparation steps are exactly the same as those of example 1.

[0048] Example 5 The aluminum alloy conductor preparation process flow of Al-1.2Si-0.2Mg-0.025Cu-0.02La-0.08B is shown in Figure 1 .

[0049] According to the mass percentage of each element in the Al-1.2Si-0.2Mg-0.025Cu-0.02Y-0.08B aluminum alloy, the raw materials are prepared: this example is used to illustrate the influence of alloy composition on the performance of the conductor. The preparation steps of the conductor are as follows: Step S1: batching, taking pure aluminum 440.08 kg, Al-20Si intermediate alloy 23.36 kg, Al-10Mg intermediate alloy 9.60 kg, Al-50Cu intermediate alloy 0.24 kg, Al-5La intermediate alloy 1.92 kg, Al-8B intermediate alloy 4.8 kg, hexachloroethane 0.96 kg.

[0050] Step S2: flame direct injection smelting, the low-iron aluminum ingot in step S1 is placed in a pilot smelting furnace, mixed gas of natural gas and air is introduced into the furnace, the flame generated by ignition heats the material, the temperature is raised to 720 ℃ to make the material completely melt, and then the temperature is kept for 5 min, and the alloying agents of Si, Mg, Cu, La and B are sequentially added, and each alloying agent is stirred for 3 min and kept for 10 min.

[0051] Other preparation steps are exactly the same as those in Example 1.

[0052] Example 6 The preparation process flow of the Al-0.8Si-0.3Mg-0.1Cu-0.1Er-0.12B aluminum alloy conductor is shown in Figure 1 .

[0053] According to the mass percentage of each element in the Al-0.8Si-0.3Mg-0.1Cu-0.1Er-0.12B aluminum alloy, the raw materials thereof are prepared: this example is used to illustrate the influence of alloy composition on the performance of the conductor. The preparation steps of the conductor are as follows: Step S1: batching, taking pure aluminum 438.88 kg, Al-20Si intermediate alloy 8.96 kg, Al-10Mg intermediate alloy 14.40 kg, Al-50Cu intermediate alloy 0.96 kg, Al-5Er intermediate alloy 9.60 kg, Al-8B intermediate alloy 7.20 kg, hexachloroethane 0.96 kg.

[0054] Step S2: flame direct injection smelting, the low-iron aluminum ingot in step S1 is placed in a pilot smelting furnace, mixed gas of natural gas and air is introduced into the furnace, the flame generated by ignition heats the material, the temperature is raised to 720 ℃ to make the material completely melt, and then the temperature is kept for 5 min, and the alloying agents of Si, Mg, Cu, La and B are sequentially added, and each alloying agent is stirred for 3 min and kept for 10 min.

[0055] Other preparation steps are exactly the same as those in Example 1.

[0056] Example 7 The preparation process flow of the Al-0.8Si-0.3Mg-0.1Cu-0.1Er-0.12B aluminum alloy conductor is shown in Figure 1 .

[0057] The raw materials are prepared according to the mass percentage of each element in the Al-0.8Si-0.3Mg-0.1Cu-0.1Er-0.12B aluminum alloy: this example is used to illustrate the influence of alloy composition on the performance of the conductor. The preparation steps of the conductor are as follows: Step S1: batching, taking pure aluminum 434.08 kg, Al-20Si intermediate alloy 13.76 kg, Al-10Mg intermediate alloy 14.40 kg, Al-50Cu intermediate alloy 0.96 kg, Al-5Er intermediate alloy 9.60 kg, Al-8B intermediate alloy 7.20 kg, hexachloroethane 0.96 kg.

[0058] The other preparation steps are exactly the same as those in Example 1.

[0059] Example 8 The preparation process flow of the Al-1Si-0.3Mg-0.1Cu-0.1Er-0.12B aluminum alloy conductor is shown in Figure 1 .

[0060] The raw materials are prepared according to the mass percentage of each element in the Al-0.8Si-0.3Mg-0.1Cu-0.1Er-0.12B aluminum alloy: this example is used to illustrate the influence of alloy composition on the performance of the conductor. The preparation steps of the conductor are as follows: Step S1: batching, taking pure aluminum 434.08 kg, Al-20Si intermediate alloy 13.76 kg, Al-10Mg intermediate alloy 14.40 kg, Al-50Cu intermediate alloy 0.96 kg, Al-5Er intermediate alloy 9.60 kg, Al-8B intermediate alloy 7.20 kg, hexachloroethane 0.96 kg.

[0061] The other preparation steps are exactly the same as those in Example 1.

[0062] Example 9 The preparation process flow of the Al-1.4Si-0.05Mg-0.05Cu-0.01Er-0.04B aluminum alloy conductor is shown in Figure 1 .

[0063] The raw materials are prepared according to the mass percentage of each element in the Al-0.8Si-0.3Mg-0.1Cu-0.1Er-0.12B aluminum alloy: this example is used to illustrate the influence of alloy composition on the performance of the conductor. The preparation steps of the conductor are as follows: Step S1: batching, taking pure aluminum 445.60 kg, Al-20Si intermediate alloy 28.16 kg, Al-10Mg intermediate alloy 2.40 kg, Al-50Cu intermediate alloy 0.48 kg, Al-5Er intermediate alloy 0.96 kg, Al-8B intermediate alloy 2.40 kg, hexachloroethane 0.96 kg.

[0064] Other preparation steps are exactly the same as Example 1.

[0065] Comparative Example 1 The preparation process flow of the Al-1.6Si-0.2Mg-0.025Cu-0.02Er-0.08B aluminum alloy wire is shown in Figure 1 .

[0066] This comparative example aims to examine the influence of alloy formula on the performance of the alloy. The alloy formula uses a Si content that exceeds the scope of the claims, i.e. is formulated according to a mass percentage of Si in the alloy of 1.6%. Compared with Example 1, the preparation process parameters are exactly the same except for the different ingredients in Step S1.

[0067] Step S1: batching, taking pure aluminum 430.48 kg, Al-20Si intermediate alloy 32.96 kg, Al-10Mg intermediate alloy 9.60 kg, Al-50Cu intermediate alloy 0.24 kg, Al-5Er intermediate alloy 1.92 kg, Al-8B intermediate alloy 4.80 kg, hexachloroethane 0.96 kg.

[0068] Comparative Example 2 The preparation process flow of the Al-0.4Si-0.2Mg-0.025Cu-0.02Er-0.08B aluminum alloy wire is shown in Figure 1 .

[0069] This comparative example aims to examine the influence of alloy formula on the performance of the alloy. The alloy formula uses a Si content that is lower than the scope of the claims, i.e. is formulated according to a mass percentage of Si in the alloy of 0.4%. Compared with Example 1, the preparation process parameters are exactly the same except for the different ingredients in Step S1.

[0070] Step S1: batching, taking pure aluminum 459.28 kg, Al-20Si intermediate alloy 4.16 kg, Al-10Mg intermediate alloy 9.60 kg, Al-50Cu intermediate alloy 0.24 kg, Al-5Er intermediate alloy 1.92 kg, Al-8B intermediate alloy 4.80 kg, hexachloroethane 0.96 kg.

[0071] Comparative Example 3 The preparation process flow of the Al-1.2Si-0.2Mg-0.025Cu-0.08B aluminum alloy wire is shown in Figure 1 .

[0072] The present comparative example is intended to examine the influence of the alloy formula on the alloy performance. No rare earth element is added in the alloy formula, and the proportions of other alloy elements in the alloy are completely the same as those in Example 1. Compared with Example 1, the preparation process method is completely the same except that the ingredient in step S1 is different.

[0073] Step S1: ingredient, 442.00 kg of pure aluminum, 23.36 kg of Al-20Si intermediate alloy, 9.60 kg of Al-10Mg intermediate alloy, 0.24 kg of Al-50Cu intermediate alloy, 4.80 kg of Al-8B intermediate alloy, and 0.96 kg of hexachloroethane are weighed.

[0074] Comparative Example 4 The preparation process flow of the Al-1.2Si-0.2Mg-0.025Cu-0.02Er-0.08B aluminum alloy wire is shown in Figure 3 .

[0075] The present comparative example is intended to examine the influence of the aging and annealing simultaneous heat treatment condition on the alloy performance. Compared with Example 1, the alloy formula of the comparative example is completely the same as that of Example 1, but the temperature of the aging and annealing simultaneous heat treatment in step S6 exceeds the protection scope, i.e., 200 ℃ (a conventional annealing temperature), and the rest of the process parameters are completely the same as those of Example 1.

[0076] Step S6: aging and annealing simultaneous heat treatment The aluminum alloy wire obtained in step S5 is subjected to aging and annealing treatment, i.e., the aluminum alloy wire is heated to 200 ℃, the holding time is 24 h, and the furnace cooling is performed, so as to prepare the aluminum alloy wire.

[0077] Table 1: alloy formula (kg) of the examples and comparative examples For the convenience of comparison, the main mechanical performance indexes and the electrical conductivity indexes of the examples and comparative examples are listed in Table 2, and the details are as follows: Table 2: test data of the mechanical performance and the electrical conductivity of the prepared aluminum alloy wire at room temperature (20 ℃) As Figure 4 , Figure 3As shown, the high-conductivity aluminum alloy wires in Examples 1-9 can simultaneously meet the requirements of GB / T 30552-2014 in terms of mechanical properties and electrical properties under the scientific formula and the matching preparation process conditions. In addition, the performance of the aluminum alloy wires is significantly higher than the lower limit value of the national standard (Note: from a technical point of view, the more the electrical conductivity of the aluminum alloy wire approaches that of pure aluminum, the more difficult it is to improve the mechanical properties). Figure 4 As shown, the soft tensile strength of the aluminum alloy wires in all examples is above 110 MPa, and even the tensile strength of most examples is above 120 MPa, while the elongation is ≥14%, both of which are within the range specified in the national standard. The plasticity of Comparative Examples 1, 3, and 4 is lower and does not meet the range specified in the standard (≥10%). Although the plasticity of Comparative Example 2 is higher, the tensile strength does not meet the requirement specified in the standard (≥98 MPa). ​ As shown, the electrical conductivity of the aluminum alloy wires in all examples is ≥62% IACS, while the electrical conductivity of the aluminum alloy wires in Comparative Examples 1 and 3 is <61% IACS, which is not within the range specified in the standard (≥61% IACS).

[0078] Comparative Example 1 may have a high content of the alloying element Si, resulting in a large number of second phases in the alloy, which limits the elongation of the alloy and makes it lower than the national standard. Comparative Example 2 has a low content of the alloying element Si, which reduces the proportion of the second phase in the alloy and thus reduces the second phase strengthening effect, resulting in insufficient tensile strength of the alloy and failing to meet the national standard. Comparative Example 3 does not contain rare earth elements, which reduces the grain refinement effect of the alloying elements on the aluminum alloy, resulting in slightly low plasticity of the alloy and failing to meet the requirements of the national standard. Comparative Example 4 has a low simultaneous aging annealing temperature, which retains the hard and brittle characteristics caused by work hardening during cold forming of the alloy, thereby severely reducing the plasticity of the alloy. In addition, due to the low simultaneous aging annealing temperature, element diffusion is difficult, resulting in a high concentration of solid solution alloy atoms in the alloy, which causes large lattice distortion in the alloy and severely reduces the electrical conductivity of the alloy. In summary, the three indicators of tensile strength, elongation, and electrical conductivity of the alloy wires prepared in all comparative examples cannot simultaneously meet the requirements of the national standard for aluminum alloy wires for cables.

[0079] In summary, the energy-saving and efficient aluminum alloy wire prepared by the present application has excellent electrical properties and good mechanical properties within the scope of the patent protection, and is expected to become a new type of practical high-conductivity aluminum alloy wire with good application prospects in aluminum alloy cores for cables. The process flow of the method is short, easy to operate, low in energy consumption and production cost, and suitable for industrialization. The wire is suitable for medium and low voltage cables for power transmission and has excellent application and promotion prospects.

[0080] The foregoing description of specific exemplary embodiments of the application has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the application to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. It is intended that the scope of the application be limited not with this detailed description, but rather by the claims appended hereto.

Claims

1. A method for energy efficient, high performance aluminum alloy wire production, characterized in that, The nominal composition of the high-performance aluminum alloy wire is Al- x Si- y Mg- z Cu- m RE- n B, the coefficient x, y, z, m, n is the mass percentage content of Si, Mg, Cu and B in the alloy respectively, wherein 0.6≤ x ≤1.4, 0.05≤ y ≤0.3, z ≤0.1, 0.01≤ m ≤0.1, 0.04≤ n ≤0.12; The preparation method of the high-performance aluminum alloy wire comprises the following steps: Step S1: batching Each raw material component is weighed according to the mass proportion; Step S2: flame direct injection smelting Each raw material component is placed in a smelting furnace and smelted by flame direct injection; Step S3: refining A refining agent is added to the smelting furnace for refining, and then the refined melt is transferred into a buffer furnace, and the melt temperature in the buffer furnace is controlled to be 700-720 ℃; The bottom of the buffer furnace is provided with an aluminum alloy wire rod forming die, the aluminum alloy wire rod forming die is provided with a through hole, the center line of the through hole is parallel to the bottom of the buffer furnace, one end of the through hole is connected with the melt in the buffer furnace, and the other end leads to the outside of the buffer furnace; Step S4: synchronous water quenching and drawing The height difference between the melt surface in the buffer furnace and the center line of the through hole of the aluminum alloy wire rod forming die is controlled, the furnace temperature is controlled to be kept at 690-710 ℃, then the opening of the through hole of the die is opened, the aluminum alloy liquid slowly flows out from one end of the through hole to the other end of the through hole, the aluminum alloy liquid just flowed out is instantaneously and quickly water quenched to form a wire rod, while the wire rod is being water quenched, the cooling end of the wire rod is wound on an automatic take-up machine, the rotating speed of the take-up machine is controlled, and the wire rod is slowly drawn out of the through hole of the die, thereby obtaining an aluminum alloy wire rod; Step S5: cold forming processing The aluminum alloy wire rod is cold rolled and cold drawn to obtain a hard state aluminum alloy wire; Step S6: aging annealing synchronous heat treatment The hard state aluminum alloy wire is heated to 240-260 ℃, the holding time is 6-24 h, and the furnace is cooled, thereby obtaining the high-performance aluminum alloy wire.

2. A method of energy efficient, high performance aluminum alloy wire production as claimed in claim 1, wherein, In step S1, the batching is as follows: low-iron industrial pure aluminum is weighed as an aluminum alloy base material according to the mass proportion, and Si, Mg, Cu, RE and B aluminum-based intermediate alloy or elements are weighed as alloying agents.

3. The method of claim 2, wherein the method is characterized by, In step S2, the flame direct injection smelting is as follows: the low-iron aluminum ingot is placed in a smelting furnace, a mixed gas of combustible gas and air is introduced into the furnace, ignition is performed, high-temperature gas generated by the flame is directly sprayed onto the surface of the material for heating, the material is heated to 700-720 ℃, and then the alloying agents of Si, Mg, Cu, RE and B are sequentially added, each alloying agent is stirred for 3-5 min and is placed for 10-15 min.

4. The method of claim 1, wherein the method is characterized by, In step S3, the refining is as follows: a refining agent is added to the material after smelting in step S2, stirring is performed for 5-10 min, the material is placed for 10-15 min, slag is removed, and then the refined melt is transferred into a buffer furnace.

5. The method of claim 1, wherein the method is characterized by, In step S3, the refining agent is hexachloroethane, and the addition amount of the hexachloroethane is 0.2-0.6% of the total mass of the alloy.

6. The method of claim 1, wherein the method is characterized by, In step S4, the diameter of the wire rod is 6-12 mm.

7. The method of claim 1, wherein the method is characterized by, In step S5, the cold rolling pass is ≥10 times, and the deformation amount is ≥85%; the cold drawing pass is ≥5 times, and the deformation amount is ≥15%.

8. A high-performance aluminum alloy wire prepared by the method of any one of claims 1-7.

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