A low-cost and high-performance aluminum alloy single wire and its preparation method

Abstract

The present invention provides a low-cost and high-performance aluminum alloy single wire and a preparation method thereof. Calculated based on the total weight of the aluminum alloy single wire being 100%, it includes the following elemental composition: Fe 0.8 - 1.5%, Si ≤ 0.05%, and the balance is Al and inevitable impurity elements. The preparation method of the aluminum alloy single wire includes the following steps: According to the elemental composition and weight percentage of the aluminum alloy single wire, the raw materials are at least subjected to melting, refining, ultrasonic treatment, continuous casting and rolling, and rod drawing to prepare the aluminum alloy single wire. The aluminum alloy single wire provided by the present invention is a low-cost, high conductivity, medium-strength aluminum alloy single wire. The strength of the aluminum alloy single wire is ≥ 280 MPa, the conductivity is ≥ 59% IACS, and the elongation is ≥ 3%. Its preparation process route can meet the requirements of enterprise mass production.

Description

Technical Field

[0001] The invention relates to a low-cost and high-performance aluminum alloy monofilament and a preparation method thereof, belonging to the technical field of aluminum alloys. Background Art

[0002] Overhead transmission lines are mainly composed of ordinary steel core aluminum stranded wires, which have large power loss. Using energy-saving conductors instead of steel core aluminum stranded wires can greatly reduce the power loss of transmission lines, which has become an important development trend in the field of overhead transmission. At present, the strength of high-conductivity aluminum alloy conductors with a conductivity of 58.5% IACS is only 230-250MPa, and the conductor breaking force is insufficient. It is well known that the strength, elongation and conductivity of aluminum-magnesium-silicon alloys are mutually restricted. When the strength is increased, the elongation and conductivity of the alloy will often decrease significantly. The current aluminum-magnesium-silicon alloys and conventional process routes are difficult to achieve a significant improvement in comprehensive performance and face the problem of high production costs.

[0003] In the prior art, the process route of medium-strength aluminum-magnesium-silicon alloy wire is generally smelting → continuous casting and rolling → drawing → aging treatment. The cost and energy consumption of alloy materials are high, and the comprehensive performance of alloy monofilaments is difficult to further break through. CN103996427A discloses a non-heat-treated medium-strength aluminum alloy wire and its production process. The aluminum alloy wire is an alloy mainly composed of Fe elements, and the alloy also contains Mg, Cu, rare earth elements, etc. The preparation process of the aluminum alloy wire is relatively complicated and requires long-term annealing treatment, which also has the disadvantage of high cost.

[0004] Therefore, developing a low-cost, high-performance aluminum alloy monofilament and a preparation method thereof is still one of the problems to be solved urgently in this field. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a low-cost, high-performance aluminum alloy monofilament and a preparation method thereof. The aluminum alloy monofilament provided by the present invention is a high-conductivity, medium-strength aluminum alloy monofilament, and the production cost and energy consumption of the aluminum alloy monofilament are low.

[0006] In order to achieve the above-mentioned objectives, the first aspect of the present invention provides a low-cost, high-performance aluminum alloy monofilament, which, based on the total weight of the low-cost, high-performance aluminum alloy monofilament being 100%, comprises the following elemental composition: Fe 0.8-1.5%, Si≤0.05%, and the remainder being Al and unavoidable impurity elements.

[0007] In the above-mentioned low-cost, high-performance aluminum alloy monofilament, preferably, based on the total weight of the low-cost, high-performance aluminum alloy monofilament as 100%, the content of each impurity element in its elemental composition is ≤0.005%, and the total content of impurity elements is ≤0.02%.

[0008] According to the specific embodiments of the present invention, preferably, the low-cost and high-performance aluminum alloy single wire is prepared through at least the following steps: according to the element composition and weight percentage of the low-cost and high-performance aluminum alloy single wire, the raw materials are at least melted, refined, ultrasonically treated, continuously cast and rolled, and rod drawing is carried out to prepare the low-cost and high-performance aluminum alloy single wire;

[0009] Among them, the ultrasonic treatment includes: carrying out on-line ultrasonic treatment on the refined melt, with the ultrasonic power being 2-5 Kw and the frequency being 1.8-2.5 KHz;

[0010] The continuous casting and rolling includes: pouring the melt after ultrasonic treatment into a wheel type crystallizer for continuous casting to form a billet, and the billet enters a continuous rolling mill for continuous rolling. Before rolling, the billet is heated by an intermediate frequency heating device, the rolling inlet temperature is controlled at 530-550 °C, the preheating temperature of the emulsion is adjusted at 40-60 °C, the emulsion flow rate is 120-180 L / min, the final rolling temperature is above 350 °C, and an aluminum alloy rod is obtained after rolling.

[0011] In the above-mentioned low-cost and high-performance aluminum alloy single wire, preferably, in the preparation steps of the low-cost and high-performance aluminum alloy single wire, the raw materials used include aluminum ingots and iron agents, etc.

[0012] In the above-mentioned low-cost and high-performance aluminum alloy single wire, preferably, in the preparation steps of the low-cost and high-performance aluminum alloy single wire, the melting includes: according to the element composition and weight percentage of the low-cost and high-performance aluminum alloy single wire, adding aluminum ingots and iron agents into a melting furnace, heating and melting, and fully stirring.

[0013] In the above-mentioned low-cost and high-performance aluminum alloy single wire, preferably, in the preparation steps of the low-cost and high-performance aluminum alloy single wire, the refining includes in-furnace refining and on-line refining;

[0014] The in-furnace refining includes: transferring the melt obtained by melting to a tilting holding furnace, starting the electromagnetic stirring device at the bottom of the tilting holding furnace to fully stir the melt, adjusting the melt temperature to 730-750 °C for in-furnace refining for 10-15 minutes, then thoroughly skimming the scum on the surface of the melt, and then adjusting the temperature of the melt to 720-730 °C and standing for 30-40 minutes;

[0015] The on-line refining includes: after casting starts, carrying out on-line degassing and on-line filtering on the melt; among them, on-line degassing uses a rotary spray degassing box; on-line filtering uses a two-stage foam ceramic filter box.

[0016] In the above-mentioned low-cost and high-performance aluminum alloy single wire, preferably, in the preparation step of the low-cost and high-performance aluminum alloy single wire, the melt after the ultrasonic treatment contains Al3Fe phase and Al6Fe phase.

[0017] In the above-mentioned low-cost and high-performance aluminum alloy single wire, preferably, in the preparation step of the low-cost and high-performance aluminum alloy single wire, the average grain size of the billet is less than 50 μm.

[0018] In the above-mentioned low-cost and high-performance aluminum alloy single wire, preferably, in the preparation step of the low-cost and high-performance aluminum alloy single wire, the continuous rolling mill uses a three-high rolling mill; more preferably, the continuous rolling mill uses a 15-stand three-high rolling mill.

[0019] In the above-mentioned low-cost and high-performance aluminum alloy single wire, preferably, in the preparation step of the low-cost and high-performance aluminum alloy single wire, the diameter of the aluminum alloy rod is 9-10 mm.

[0020] The present invention uses a melt refined by ultrasonic treatment to form a local supercooled zone in the melt through the cavitation effect, prompting a large amount of Fe elements to precipitate in the form of fine Al3Fe and Al6Fe phases, and refining the grain structure during the casting process. The average grain size of the billet is less than 50 μm, preventing the formation of coarse acicular iron-rich phases in the alloy and improving the plasticity of the alloy. Moreover, the present invention keeps the alloy at a relatively high temperature throughout the rolling process and air-cools and winds up the rod after rolling, using the waste heat to promote the precipitation of a small amount of Fe elements in the solid solution state in the alloy.

[0021] In the above-mentioned low-cost and high-performance aluminum alloy single wire, preferably, in the preparation step of the low-cost and high-performance aluminum alloy single wire, the rod drawing includes: drawing the aluminum alloy rod using a sliding wire drawing machine to obtain the above-mentioned low-cost and high-performance aluminum alloy single wire.

[0022] According to a specific embodiment of the present invention, preferably, the diameter of the low-cost and high-performance aluminum alloy single wire is 2.5-4 mm.

[0023] According to a specific embodiment of the present invention, preferably, the strength of the low-cost and high-performance aluminum alloy single wire is ≥280 MPa, the conductivity is ≥59% IACS, and the elongation is ≥3%.

[0024] The second aspect of the present invention provides a preparation method of the above-mentioned low-cost and high-performance aluminum alloy single wire, which includes the following steps: according to the element composition and weight percentage of the low-cost and high-performance aluminum alloy single wire, at least melting, refining, ultrasonic treatment, continuous casting and rolling, and rod drawing of the raw materials are carried out to prepare the above-mentioned low-cost and high-performance aluminum alloy single wire;

[0025] Among them, the ultrasonic treatment includes: performing on-line ultrasonic treatment on the refined melt, with the ultrasonic power being 2 - 5 Kw and the frequency being 1.8 - 2.5 KHz;

[0026] The continuous casting and rolling includes: pouring the melt after ultrasonic treatment into a wheel-type crystallizer for continuous casting to form a billet, and the billet enters a continuous rolling mill for continuous rolling. Before rolling, the billet is heated by an intermediate frequency heating device, the rolling inlet temperature is controlled at 530 - 550 °C, the preheating temperature of the emulsion is adjusted to be 40 - 60 °C, the emulsion flow rate is 120 - 180 L / min, the final rolling temperature is above 350 °C, and an aluminum alloy rod is obtained after rolling.

[0027] In the above preparation method, preferably, the raw materials used include aluminum ingots and iron agents, etc.

[0028] In the above preparation method, preferably, the melting includes: adding aluminum ingots and iron agents to a melting furnace according to the element composition and weight percentage of the low-cost and high-performance aluminum alloy single wire, heating and melting, and fully stirring.

[0029] In the above preparation method, preferably, the refining includes in-furnace refining and on-line refining;

[0030] The in-furnace refining includes: transferring the melt obtained by melting to a tilting holding furnace, starting the electromagnetic stirring device at the bottom of the tilting holding furnace to fully stir the melt, adjusting the melt temperature to 730 - 750 °C for in-furnace refining for 10 - 15 minutes, then thoroughly skimming the scum on the melt surface, and then adjusting the melt temperature to 720 - 730 °C and standing for 30 - 40 minutes;

[0031] The on-line refining includes: after casting starts, performing on-line degassing and on-line filtering on the melt; among them, on-line degassing uses a rotary spray degassing box; on-line filtering uses a two-stage foam ceramic filter box.

[0032] In some specific embodiments of the present invention, preferably, the degassing medium of the rotary spray degassing box is high-purity nitrogen, and the rotation speed of the graphite rotor is 400 - 500 r / min. Through on-line degassing, the hydrogen content in the melt can be < 0.12 ml / 100 g.

[0033] In some specific embodiments of the present invention, preferably, the porosity of the double-stage foam ceramic filter box is 30 / 50 PPI. The double-stage foam ceramic filter box includes two layers of foam ceramic filter plates. The pore size of the first layer of filter plate is larger (30 PPI), mainly filtering large-size inclusions. The pore size of the second layer of filter plate is smaller (50 PPI), filtering small-size inclusions. The double-stage filtration has the advantages of a wider filtration range and higher filtration accuracy. The present invention adopts a double-stage foam ceramic filter box with a porosity of 30 / 50 PPI, which can better remove inclusions with a size of 5-10 μm in the melt and reduce the adverse effects of inclusions on the elongation rate of the alloy monofilament.

[0034] In the above preparation method, preferably, the melt after the ultrasonic treatment contains Al3Fe phase and Al6Fe phase.

[0035] In the above preparation method, preferably, the average grain size of the billet is less than 50 μm.

[0036] In the above preparation method, preferably, the continuous rolling mill unit adopts a three-roll rolling mill; more preferably, the continuous rolling mill unit adopts a three-roll rolling mill with 15 stands.

[0037] In the above preparation method, preferably, the diameter of the aluminum alloy rod is 9-10 mm.

[0038] According to the specific embodiments of the present invention, in the process of continuous casting and rolling, the equipment used for continuous casting and continuous rolling can be the equipment in the prior art, and the emulsifying liquid used can be the conventional emulsifying liquid in the aluminum alloy continuous rolling technology.

[0039] In the above preparation method, preferably, the rod drawing includes: using a sliding wire drawing machine to draw the aluminum alloy rod to obtain an aluminum alloy monofilament with a diameter of 2.5-4 mm, which is the low-cost and high-performance aluminum alloy monofilament.

[0040] The present invention provides a low-cost and high-performance aluminum alloy monofilament and a preparation method thereof. The aluminum alloy monofilament provided by the present invention is a low-cost, high-conductivity, medium-strength aluminum alloy monofilament. The strength of the aluminum alloy monofilament is ≥280 MPa, the conductivity is ≥59% IACS, and the elongation rate is ≥3%. Its preparation process route can meet the requirements of enterprise batch production.

[0041] The technical solution of the present invention has at least the following beneficial effects:

[0042] (1) In the alloy element composition of the present invention, except for the Al element, it basically only contains the Fe element. Therefore, the cost of the alloy material is extremely low, and the solubility of the Fe element in the matrix is very small, so the influence on the electrical conductivity of the alloy is small, and the alloy can reach a very high conductivity.

[0043] (2) The present invention uses an online ultrasonic treatment method to form a large number of sub-micron-sized fine and regular Al3Fe and Al6Fe precipitation phases of Fe elements in the melt, enabling the alloy to obtain high strength and minimizing its adverse effects on plasticity. At the same time, the fine iron-containing phases produce an excellent grain refinement effect during solidification, making the average as-cast grain size less than 50 μm.

[0044] (3) The preparation process of the aluminum alloy single wire of the present invention is simple, does not require long-term aging treatment, has low energy consumption and high production efficiency, and does not require additional addition of grain refiners, thus further reducing the production cost. Description of the Drawings

[0045] Figure 1 It is the as-cast grain microstructure diagram of the ingot blank in Example 1. Detailed Embodiments

[0046] For a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the technical solutions of the present invention will be described in detail below, but it should not be construed as a limitation on the implementable scope of the present invention.

[0047] According to the specific embodiments of the present invention, by weight percentage, the low-cost and high-performance aluminum alloy single wire provided by the present invention includes the following elemental compositions: Fe 0.8 - 1.5%, Si ≤ 0.05%, the balance being Al and unavoidable impurity elements, and the content of each impurity element is ≤ 0.005%, and the total content of impurity elements is ≤ 0.02%.

[0048] According to the specific embodiments of the present invention, the process flow of the preparation method of the low-cost and high-performance aluminum alloy single wire provided by the present invention is as follows:

[0049] Melting → In-furnace refining → Standing → Casting → Online degassing → Online filtration → Ultrasonic treatment → Continuous casting and rolling → Rod drawing.

[0050] Specifically, the preparation method of the low-cost and high-performance aluminum alloy single wire provided by the present invention includes the following steps:

[0051] (1) Melting of aluminum liquid

[0052] According to the elemental composition and weight percentage of the low-cost and high-performance aluminum alloy single wire, aluminum ingots with a purity greater than 99.7% and iron agents are added to the melting furnace, heated and melted, and the melted aluminum liquid is stirred evenly.

[0053] (2) In-furnace refining

[0054] Transfer the melt in the smelting furnace to a tilting holding furnace, turn on the electromagnetic stirring device at the bottom of the tilting holding furnace to fully stir the melt, adjust the melt temperature to 730 - 750 °C for in-furnace refining for 10 - 15 minutes, then completely remove the scum on the melt surface, and then adjust the melt temperature to 720 - 730 °C and let it stand for 30 - 40 minutes;

[0055] (3) In-line refining

[0056] After casting starts, conduct in-line degassing and in-line filtration on the melt. For in-line degassing, use a rotary spray degassing box with high-purity nitrogen as the degassing medium and the graphite rotor speed of 400 - 500 r / min; for in-line filtration, use a two-stage foam ceramic filter box with a porosity of 30 / 50 PPI to remove inclusions with a size of 5 - 10 μm in the melt and reduce the adverse effects of inclusions on the elongation rate of alloy monofilaments;

[0057] (4) Ultrasonic treatment

[0058] Conduct in-line ultrasonic treatment on the refined melt in the launder. The ultrasonic power is 2 - 5 Kw and the frequency is 1.8 - 2.5 KHz. Through the cavitation effect, form local supercooled zones in the melt, promote a large amount of Fe elements to precipitate in the form of fine Al3Fe and Al6Fe phases, refine the grain structure during the subsequent casting process, and prevent the formation of coarse needle-shaped iron-rich phases in the alloy, improving the plasticity of the alloy;

[0059] (5) Continuous casting and rolling

[0060] Pour the melt after ultrasonic treatment into a wheel-type mold for continuous casting to form a billet. The average grain size of the billet is less than 50 μm. The billet enters a continuous rolling mill. The continuous rolling mill uses a three-high rolling mill with 15 stands. Before rolling, use an intermediate frequency heating device to heat the billet, control the rolling-in temperature to 530 - 550 °C, adjust the preheating temperature of the emulsion to 40 - 60 °C, the emulsion flow rate to 120 - 180 L / min, and the final rolling temperature to above 350 °C, so that the alloy maintains a relatively high temperature during the entire rolling process, promoting the precipitation of a small amount of Fe elements in the solid solution state in the alloy. After rolling, air-cool and wind up to obtain an aluminum alloy rod with a diameter of 9 - 10 mm;

[0061] (6) Rod drawing

[0062] Draw the aluminum alloy rod on a sliding wire drawing machine to obtain an aluminum alloy monofilament with a diameter of 2.5 - 4 mm, which is the low-cost and high-performance aluminum alloy monofilament described.

[0063] Example 1

[0064] This example provides a low-cost and high-performance aluminum alloy monofilament, which is prepared through the following steps:

[0065] (1) According to the designed elemental composition and weight percentage of the aluminum alloy single wire, add aluminum ingots with a purity greater than 99.7% and iron agents to the melting furnace, heat and melt them, and fully stir the molten aluminum after melting until it is evenly mixed;

[0066] (2) Transfer the melt in the melting furnace to a tilting holding furnace, turn on the electromagnetic stirring device at the bottom of the tilting holding furnace to fully stir the melt, adjust the melt temperature to 740 °C for in-furnace refining for 12 minutes, then completely skim off the scum on the surface of the melt, and then adjust the melt temperature to 723 °C and let it stand for 30 minutes;

[0067] (3) After casting starts, perform online degassing and online filtration on the melt. For online degassing, use a rotary spray degassing box with high-purity nitrogen as the degassing medium and a graphite rotor speed of 450 r / min; for online filtration, use a two-stage foam ceramic filter box with a porosity of 30 / 50 PPI to remove inclusion particles with a size of 5 - 10 μm in the melt and reduce the adverse effects of inclusions on the elongation of the alloy single wire;

[0068] (4) Perform online ultrasonic treatment on the refined melt in the launder. The ultrasonic power is 3 Kw and the frequency is 2.2 KHz. Through the cavitation effect, form local supercooled regions in the melt, promote a large amount of Fe elements to precipitate in the form of fine Al3Fe and Al6Fe phases, refine the grain structure, and prevent the formation of coarse needle-like iron-rich phases in the alloy, improving the plasticity of the alloy;

[0069] (5) Pour the melt after ultrasonic treatment into a wheel-type crystallizer for continuous casting to form a billet. As shown in Figure 1 , the average grain size of the billet is less than 50 μm. The billet enters a three-high rolling mill with 15 stands for continuous rolling. Before rolling, use an intermediate frequency heating device to heat the billet, control the rolling-in temperature to 540 °C, adjust the preheating temperature of the emulsion to 40 °C, the emulsion flow rate to 150 L / min, and the final rolling temperature to be above 350 °C, so that the alloy maintains a relatively high temperature throughout the rolling process, promoting the precipitation of a small amount of Fe elements in the solid solution state in the alloy. After rolling, air-cool and wind up to obtain an aluminum alloy rod with a diameter of 9.5 mm;

[0070] (6) Draw the aluminum alloy rod on a sliding wire drawing machine to obtain an aluminum alloy single wire with a diameter of 3.5 mm, which is the low-cost and high-performance aluminum alloy single wire described above.

[0071] Through analysis and testing, by weight percentage, the elemental composition of the low-cost and high-performance aluminum alloy single wire in this embodiment is: Fe 0.94%, Si 0.05%, the balance being Al and inevitable impurity elements, and the content of each impurity element is ≤0.005%, and the total content of impurity elements is ≤0.02%.

[0072] The average strength of the low-cost and high-performance aluminum alloy single wire provided by this embodiment is 283 MPa, the elongation rate is 3.5%, and the conductivity is 59.7% IACS.

[0073] Example 2

[0074] This embodiment provides a low-cost and high-performance aluminum alloy single wire, which is prepared by the following steps:

[0075] (1) According to the designed elemental composition and weight percentage of the aluminum alloy single wire, aluminum ingots with a purity greater than 99.7% and iron agents are added to the melting furnace, heated and melted, and the melted aluminum liquid is fully stirred evenly;

[0076] (2) The melt in the melting furnace is transferred to a tilting holding furnace, and the electromagnetic stirring device at the bottom of the tilting holding furnace is turned on to fully stir the melt. The temperature of the melt is adjusted to 740 °C for in-furnace refining for 15 minutes, and then the scum on the surface of the melt is completely skimmed off. After that, the temperature of the melt is adjusted to 720 °C and left standing for 30 minutes;

[0077] (3) After the casting starts, online degassing and online filtering are carried out on the melt. The online degassing uses a rotary spray degassing box, with high-purity nitrogen as the degassing medium and the graphite rotor speed of 450 r / min; the online filtering uses a two-stage foam ceramic filter box with a porosity of 30 / 50 PPI to remove inclusions with a size of 5-10 μm in the melt and reduce the adverse effects of inclusions on the elongation rate of the alloy single wire;

[0078] (4) Online ultrasonic treatment is carried out on the refined melt in the launder. The ultrasonic power is 3 Kw and the frequency is 2.2 KHz. Through the cavitation effect, a local supercooled zone is formed in the melt, promoting a large amount of Fe elements to precipitate in the form of fine Al3Fe and Al6Fe phases, refining the grain structure, and preventing the formation of coarse needle-shaped iron-rich phases in the alloy, improving the plasticity of the alloy;

[0079] (5) The melt after ultrasonic treatment is poured into a wheel-type crystallizer for continuous casting to form a billet. The average grain size of the billet is less than 50 μm. The billet enters a three-high rolling mill with 15 stands for continuous rolling. Before rolling, the billet is heated by an intermediate frequency heating device, and the rolling inlet temperature is controlled at 545 °C. The preheating temperature of the emulsion is adjusted to 40 °C, the emulsion flow rate is 150 L / min, and the final rolling temperature is above 350 °C, so that the alloy maintains a relatively high temperature during the whole rolling process, promoting the precipitation of a small amount of Fe elements in the solid solution state in the alloy. After rolling, it is air-cooled and coiled to obtain an aluminum alloy rod with a diameter of 9.5 mm;

[0080] (6) The aluminum alloy rod is drawn on a sliding wire drawing machine, and after drawing, an aluminum alloy single wire with a diameter of 3.8 mm is obtained, which is the low-cost and high-performance aluminum alloy single wire described above.

[0081] After analysis and testing, by weight percentage, the element composition of the low-cost and high-performance aluminum alloy single wire in this embodiment is: Fe 1.06%, Si 0.05%, and the balance is Al and inevitable impurity elements, and the content of each impurity element is ≤ 0.005%, and the total content of impurity elements is ≤ 0.02%.

[0082] The average strength of the low-cost and high-performance aluminum alloy single wire provided in this embodiment is 288 MPa, the elongation is 3.3%, and the conductivity is 59.4% IACS.

[0083] Example 3

[0084] This embodiment provides a low-cost and high-performance aluminum alloy single wire, which is prepared by the following steps:

[0085] (1) According to the element composition and weight percentage of the designed aluminum alloy single wire, aluminum ingots with a purity greater than 99.7% and iron agents are added to the melting furnace, heated and melted, and the melted aluminum liquid is fully stirred evenly;

[0086] (2) The melt in the melting furnace is transferred to a tilting holding furnace, and the electromagnetic stirring device at the bottom of the tilting holding furnace is turned on to fully stir the melt. The temperature of the melt is adjusted to 740 °C for in-furnace refining for 15 minutes, and then the floating slag on the surface of the melt is completely removed. After that, the temperature of the melt is adjusted to 720 °C and left standing for 30 minutes;

[0087] (3) After the casting starts, online degassing and online filtration are carried out on the melt. The online degassing uses a rotary spray degassing box, with high-purity nitrogen as the degassing medium and the graphite rotor speed of 450 r / min; the online filtration uses a two-stage foam ceramic filter box with a porosity of 30 / 50 PPI to remove inclusions with a size of 5 - 10 μm in the melt and reduce the adverse effect of inclusions on the elongation of the alloy single wire;

[0088] (4) Online ultrasonic treatment is carried out on the refined melt in the launder. The ultrasonic power is 3 Kw and the frequency is 2.2 KHz. Through the cavitation effect, a local supercooled zone is formed in the melt, promoting a large amount of Fe elements to precipitate in the form of fine Al3Fe phase and Al6Fe phase, refining the grain structure, preventing the formation of coarse needle-like iron-rich phases in the alloy, and improving the plasticity of the alloy;

[0089] (5) The melt after ultrasonic treatment is poured into a wheel-shaped crystallizer for continuous casting to form a billet. The average grain size of the billet is less than 50 μm. The billet enters a three-high rolling mill with 15 stands for continuous rolling. Before rolling, the billet is heated by an intermediate frequency heating device, the rolling-in temperature is controlled at 545 °C, the preheating temperature of the emulsion is adjusted to 50 °C, the emulsion flow rate is 150 L / min, and the final rolling temperature is above 350 °C, so that the alloy maintains a relatively high temperature during the whole rolling process, promoting the precipitation of a small amount of Fe elements in the solid solution state in the alloy. After rolling, it is air-cooled and coiled to obtain an aluminum alloy rod with a diameter of 9.5 mm;

[0090] (6) The aluminum alloy rod is drawn on a sliding wire drawing machine, and an aluminum alloy single wire with a diameter of 3.8 mm is obtained after drawing, which is the low-cost and high-performance aluminum alloy single wire described above.

[0091] Through analysis and testing, by weight percentage, the element composition of the low-cost and high-performance aluminum alloy single wire in this embodiment is: Fe 1.15%, Si 0.04%, and the balance is Al and inevitable impurity elements, and the content of each impurity element is ≤0.005%, and the total content of impurity elements is ≤0.02%.

[0092] The average strength of the low-cost and high-performance aluminum alloy single wire provided in this embodiment is 295 MPa, the elongation is 3.1%, and the conductivity is 59% IACS.

[0093] Comparative Example 1

[0094] This comparative example provides an aluminum alloy single wire, which is prepared through the following steps:

[0095] (1) According to the element composition and weight percentage of the designed aluminum alloy single wire, aluminum ingots with a purity greater than 99.7% and iron agents are added to a melting furnace, heated and melted, and the melted aluminum liquid is stirred evenly.

[0096] (2) The melt in the melting furnace is transferred to a tilting holding furnace, and the electromagnetic stirring device at the bottom of the tilting holding furnace is turned on to fully stir the melt. The temperature of the melt is adjusted to 740 °C for in-furnace refining for 15 minutes, and then the scum on the surface of the melt is completely skimmed off. After that, the temperature of the melt is adjusted to 720 °C and left standing for 30 minutes.

[0097] (3) After casting starts, online degassing and online filtration are carried out on the melt. For online degassing, a rotary spray degassing box is used, with high-purity nitrogen as the degassing medium and the graphite rotor speed of 450 r / min; for online filtration, a two-stage foam ceramic filter box with a porosity of 30 / 50 PPI is used to remove inclusion particles with a size of 5 - 10 μm in the melt and reduce the adverse effect of inclusions on the elongation of the alloy single wire.

[0098] (4) The melt after online filtration is poured into a wheel-type crystallizer for continuous casting to form a billet. The billet enters a three-roll rolling mill with 15 stands for continuous rolling. Before rolling, the billet is heated by an intermediate frequency heating device, the rolling inlet temperature is controlled at 500 °C, the preheating temperature of the emulsion is adjusted to 30 °C, the emulsion flow rate is 250 L / min, the final rolling temperature is above 350 °C, and after rolling, it is air-cooled and coiled to obtain an aluminum alloy rod with a diameter of 9.5 mm;

[0099] (5) The aluminum alloy rod is drawn on a sliding wire drawing machine, and after drawing, an aluminum alloy single wire with a diameter of 3.5 mm is obtained.

[0100] After analysis and testing, by weight percentage, the elemental composition of the aluminum alloy single wire in this comparative example is: Fe 1.02%, Si 0.05%, the balance is Al and unavoidable impurity elements, and the content of each impurity element is ≤0.005%, and the total content of impurity elements is ≤0.02%.

[0101] The average strength of the aluminum alloy single wire provided in this comparative example is 275 MPa, the elongation is 1.3%, and the conductivity is 58.4% IACS.

[0102] Comparative Example 2

[0103] This comparative example provides an aluminum alloy single wire, which is prepared by the following steps:

[0104] (1) According to the elemental composition and weight percentage of the designed aluminum alloy single wire, aluminum ingots with a purity greater than 99.7% and iron agents are added to the melting furnace, heated and melted, and the melted aluminum liquid is stirred evenly.

[0105] (2) The melt in the melting furnace is transferred to a tilting holding furnace, and the electromagnetic stirring device at the bottom of the tilting holding furnace is turned on to fully stir the melt. The melt temperature is adjusted to 740 °C for in-furnace refining for 15 minutes, and then the scum on the surface of the melt is completely skimmed off. After that, the temperature of the melt is adjusted to 720 °C and left standing for 30 minutes.

[0106] (3) After casting starts, online degassing and online filtration are carried out on the melt. Online degassing uses a rotary spray degassing box with high-purity nitrogen as the degassing medium and a graphite rotor speed of 450 r / min; online filtration uses a two-stage foam ceramic filter box with a porosity of 30 / 50 PPI to remove inclusion particles of 5-10 μm in the melt and reduce the adverse effect of inclusions on the elongation of the alloy single wire.

[0107] (4) Online ultrasonic treatment is carried out on the refined melt in the launder, with an ultrasonic power of 3 Kw and a frequency of 2.2 KHz;

[0108] (5) The melt after ultrasonic treatment is poured into a wheel-shaped crystallizer for continuous casting to form a billet. The billet enters a three-roll rolling mill with 15 stands for continuous rolling. Before rolling, the billet is heated by an intermediate frequency heating device, the rolling inlet temperature is controlled at 550 °C, the preheating temperature of the emulsion is adjusted to 40 °C, the emulsion flow rate is 150 L / min, the final rolling temperature is above 350 °C, and after rolling, it is air-cooled and coiled to obtain an aluminum alloy rod with a diameter of 9.5 mm;

[0109] (6) The aluminum alloy rod is drawn on a sliding wire drawing machine, and an aluminum alloy single wire with a diameter of 3.5 mm is obtained after drawing.

[0110] After analysis and testing, by weight percentage, the elemental composition of the aluminum alloy single wire in this comparative example is: Fe 0.57%, Si 0.05%, the balance is Al and inevitable impurity elements, and the content of each impurity element is ≤0.005%, and the total content of impurity elements is ≤0.02%.

[0111] The average strength of the aluminum alloy single wire provided in this comparative example is 246 MPa, the elongation is 3.7%, and the conductivity is 60.2% IACS.

[0112] Comparative Example 3

[0113] This comparative example provides an aluminum alloy single wire, which is prepared by the following steps:

[0114] (1) According to the elemental composition and weight percentage of the designed aluminum alloy single wire, aluminum ingots with a purity greater than 99.7%, aluminum-silicon alloy, aluminum-rare earth alloy, and iron agent are added to the melting furnace, heated and melted, the magnesium ingot is added to the interior of the aluminum liquid and stirred and melted, and the melted aluminum liquid is fully stirred evenly;

[0115] (2) The melt in the melting furnace is transferred to a tilting holding furnace, a trace amount of aluminum-boron alloy is added for boronization treatment, the electromagnetic stirring device at the bottom of the tilting holding furnace is turned on to fully stir the melt, the melt temperature is adjusted to 740 °C for in-furnace refining for 15 minutes, then the surface scum of the melt is completely skimmed off, and then the temperature of the melt is adjusted to 730 °C and left standing for 30 minutes;

[0116] (3) After casting starts, online degassing and online filtration are carried out on the melt. Online degassing uses a rotary spray degassing box, with high-purity nitrogen as the degassing medium and the graphite rotor speed of 450 r / min; online filtration uses a two-stage foam ceramic filter box with a porosity of 30 / 50 PPI to remove inclusions with a size of 5 - 10 μm in the melt and reduce the adverse effects of inclusions on the elongation of the alloy single wire;

[0117] (4) When the melt flows through the launder, an Al-Ti-B grain refiner is added online for grain refinement. Based on the total weight of the melt being 100%, the addition amount of the grain refiner is 0.08%.

[0118] (5) The melt is poured into a wheel-type crystallizer for continuous casting to form a billet. The billet enters a three-roll mill with 15 stands for continuous rolling. Before rolling, the billet is heated by an intermediate frequency heating device, the rolling-in temperature is controlled at 500 °C, the preheating temperature of the emulsion is adjusted to 30 °C, the emulsion flow rate is 250 L / min, the finishing rolling temperature is above 350 °C, and after rolling, an aluminum alloy rod with a diameter of 9.5 mm is obtained and coiled after online water quenching.

[0119] (6) The aluminum alloy rod is drawn on a sliding wire drawing machine, and after drawing, an aluminum alloy single wire with a diameter of 3.5 mm is obtained.

[0120] (7) The aluminum alloy single wire obtained after drawing is subjected to aging treatment at a temperature of 155 °C and a holding time of 8 h to obtain the aluminum alloy single wire.

[0121] After analysis and testing, by weight percentage, the elemental composition of the aluminum alloy single wire in this comparative example is: Mg 0.38%, Si 0.35%, Fe 0.14%, La 0.01%, B 0.004%, Ti 0.002, and the balance is Al and inevitable impurity elements, and the content of each impurity element is ≤0.005%, and the total content of impurity elements is ≤0.02%.

[0122] The average strength of the aluminum alloy single wire provided in this comparative example is 264 MPa, the elongation is 5.3%, and the conductivity is 58.2% IACS.

[0123] In summary, the aluminum alloy single wires provided in Embodiments 1-3 of the present invention are aluminum alloy single wires with low cost, high conductivity, and medium strength. Their single wire strength ≥280 MPa, conductivity ≥59% IACS, elongation ≥3%, and their preparation process route can meet the requirements of enterprise mass production. While in Comparative Examples 1-3, either the elemental composition is not within the scope defined by the present invention, or the preparation process is different from that of the present invention, and the comprehensive performance of the obtained aluminum alloy single wires is not good.

Claims

1. A low-cost and high-performance aluminum alloy single wire, based on 100% of the total weight of the low-cost and high-performance aluminum alloy single wire, comprises the following elemental composition: Fe 0.8 - 1.5%, Si ≤ 0.05%, and the balance is Al and inevitable impurity elements; Among them, the low-cost and high-performance aluminum alloy single wire is prepared by at least the following steps: According to the element composition and weight percentage of the low-cost and high-performance aluminum alloy single wire, the raw materials are at least melted, refined, ultrasonically treated, continuously cast and rolled, and rod drawing is carried out to prepare the low-cost and high-performance aluminum alloy single wire; Among them, the ultrasonic treatment includes: performing on-line ultrasonic treatment on the refined melt, with the ultrasonic power being 2 - 5 Kw and the frequency being 1.8 - 2.5 KHz. The melt after the ultrasonic treatment contains Al3Fe phase and Al6Fe phase; The continuous casting and rolling includes: pouring the melt after ultrasonic treatment into a wheel type crystallizer for continuous casting to form a billet. The average grain size of the billet is less than 50 μm. The billet enters a continuous rolling mill for continuous rolling. Before rolling, the billet is heated by an intermediate frequency heating device, the rolling-in temperature is controlled at 530 - 550 °C, the preheating temperature of the emulsion is adjusted to be 40 - 60 °C, the emulsion flow rate is 120 - 180 L / min, the final rolling temperature is above 350 °C, and after rolling, it is air-cooled to collect the rod to obtain an aluminum alloy rod; The strength of the low-cost and high-performance aluminum alloy single wire ≥ 280 MPa, the conductivity ≥ 59% IACS, and the elongation ≥ 3%; 2. The low-cost and high-performance aluminum alloy single wire according to claim 1, wherein, Based on the total weight of the low-cost and high-performance aluminum alloy single wire being 100%, the content of each impurity element in its element composition is ≤ 0.005%, and the total content of impurity elements is ≤ 0.02%; 3. The low-cost and high-performance aluminum alloy single wire according to claim 1, wherein, The diameter of the low-cost and high-performance aluminum alloy single wire is 2.5 - 4 mm; 4. A method for preparing a low-cost and high-performance aluminum alloy single wire according to any one of claims 1-3, comprising the following steps: According to the element composition and weight percentage of the low-cost and high-performance aluminum alloy single wire, the raw materials are at least melted, refined, ultrasonically treated, continuously cast and rolled, and rod drawing is carried out to prepare the low-cost and high-performance aluminum alloy single wire; Among them, the ultrasonic treatment includes: performing on-line ultrasonic treatment on the refined melt, with the ultrasonic power being 2 - 5 Kw and the frequency being 1.8 - 2.5 KHz. The melt after the ultrasonic treatment contains Al3Fe phase and Al6Fe phase; The continuous casting and rolling includes: pouring the melt after ultrasonic treatment into a wheel type crystallizer for continuous casting to form a billet. The average grain size of the billet is less than 50 μm. The billet enters a continuous rolling mill for continuous rolling. Before rolling, the billet is heated by an intermediate frequency heating device, the rolling-in temperature is controlled at 530 - 550 °C, the preheating temperature of the emulsion is adjusted to be 40 - 60 °C, the emulsion flow rate is 120 - 180 L / min, the final rolling temperature is above 350 °C, and after rolling, it is air-cooled to collect the rod to obtain an aluminum alloy rod.

5. The preparation method according to claim 4, wherein, The melting includes: According to the element composition and weight percentage of the low-cost and high-performance aluminum alloy single wire, adding aluminum ingots and iron agents into a melting furnace, heating and melting, and fully stirring.

6. According to the preparation method described in claim 4, wherein, The refining includes in-furnace refining and on-line refining; the in-furnace refining includes: transferring the melt obtained by smelting to a tilting holding furnace, starting the electromagnetic stirring device at the bottom of the tilting holding furnace to fully stir the melt, adjusting the temperature of the melt to 730-750 °C for in-furnace refining for 10-15 minutes, then thoroughly skimming the scum on the surface of the melt, and then adjusting the temperature of the melt to 720-730 °C and standing for 30-40 minutes; the on-line refining includes: after casting starts, on-line degassing and on-line filtering of the melt; among them, on-line degassing uses a rotary spray degassing box; on-line filtering uses a two-stage foam ceramic filter box.

7. The preparation method according to claim 6, wherein, The degassing medium of the rotary spray degassing box is high-purity nitrogen, and the rotational speed of the graphite rotor is 400-500 r / min.

8. The preparation method according to claim 6, wherein The porosity of the two-stage foam ceramic filter box is 30 / 50 PPI.

9. The preparation method according to claim 4, wherein The continuous rolling mill uses a three-high rolling mill.

10. The preparation method according to claim 9, wherein, The continuous rolling mill uses a three-high rolling mill with 15 stands.

11. According to the preparation method described in claim 4, wherein, The diameter of the aluminum alloy rod is 9-10 mm.

12. The preparation method according to claim 4, wherein The rod drawing includes: drawing the aluminum alloy rod with a sliding wire drawing machine to obtain an aluminum alloy single wire with a diameter of 2.5-4 mm, which is the low-cost and high-performance aluminum alloy single wire mentioned above.

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