Low-cost and high-performance aluminum alloy monofilament and preparation method therefor

Abstract

The present invention provides a low-cost and high-performance aluminum alloy monofilament and a preparation method therefor. Taking the total weight of the aluminum alloy monofilament as 100%, the aluminum alloy monofilament consists of the following elements: Fe: 0.8-1.5%, Si≤0.05%, and the balance being Al and inevitable impurity elements. The preparation method for the aluminum alloy monofilament comprises the following steps: on the basis of the element composition and weight percentage of the aluminum alloy monofilament, at least performing smelting, refining, ultrasonic treatment, continuous casting and continuous rolling, and rod material drawing on raw materials to obtain the aluminum alloy monofilament. The aluminum alloy monofilament provided by the present invention is a low-cost, high-conductivity, and medium-strength aluminum alloy monofilament; the aluminum alloy monofilament has the strength greater than or equal to 280 MPa, the conductivity greater than or equal to 59% IACS, and the elongation greater than or equal to 3%; and the preparation process route of the aluminum alloy monofilament can meet the requirements of enterprises for mass production.

Description

A low-cost, high-performance aluminum alloy monofilament and its preparation method Technical Field

[0001] The invention relates to a low-cost, 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 the energy arteries of economic development. These lines are primarily composed of conventional steel-core aluminum stranded wire, resulting in significant power losses. Using energy-efficient conductors instead of steel-core aluminum stranded wire significantly reduces power losses and has become a key development trend in the overhead transmission sector. Currently, high-conductivity aluminum alloy conductors with a conductivity of 58.5% IACS have a strength of only 230-250 MPa, resulting in insufficient breaking force. The strength, elongation, and conductivity of aluminum-magnesium-silicon alloys are known to interact with each other. Increasing strength often results in a significant decrease in the alloy's elongation and conductivity. Current aluminum-magnesium-silicon alloys and conventional processing routes struggle to achieve significant improvements in their overall performance and face high production costs.

[0003] In the prior art, the process for producing medium-strength aluminum-magnesium-silicon alloy wire generally involves smelting, continuous casting and rolling, drawing, and aging. This results in high alloy material costs and energy consumption, making it difficult to further improve the overall performance of the alloy monofilament. CN103996427A discloses a non-heat-treated medium-strength aluminum alloy wire and its production process. This aluminum alloy wire is primarily an alloy containing Mg, Cu, and rare earth elements. The preparation process is complex, requiring lengthy annealing treatments, which also presents the disadvantage of high costs.

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

[0005] Summary of the Invention

[0006] To solve the above technical problems, the present invention aims to provide a low-cost, high-performance aluminum alloy monofilament and a method for preparing the same. The aluminum alloy monofilament provided by the present invention is a high-conductivity, medium-strength aluminum alloy monofilament with low production cost and energy consumption.

[0007] 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%, includes the following elemental composition: Fe0.8-1.5%, Si≤0.05%, and the balance being Al and unavoidable impurity elements.

[0008] 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%.

[0009] According to a specific embodiment of the present invention, preferably, the low-cost, high-performance aluminum alloy monofilament is prepared by at least the following steps: according to the element composition and weight percentage of the low-cost, high-performance aluminum alloy monofilament, the raw material is subjected to at least smelting, refining, ultrasonic treatment, continuous casting and rolling, and rod drawing to prepare the low-cost, high-performance aluminum alloy monofilament;

[0010] The ultrasonic treatment comprises: performing online ultrasonic treatment on the refined melt, with an ultrasonic power of 2-5Kw and a frequency of 1.8-2.5KHz;

[0011] The continuous casting and rolling process includes: pouring the ultrasonically treated melt into a wheel-type crystallizer for continuous casting to form a billet, which is then continuously rolled in a continuous rolling mill. Before rolling, a medium-frequency heating device is used to heat the billet, the rolling entry temperature is controlled to be 530-550° C., the emulsion preheating temperature 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 the aluminum alloy rod is obtained after rolling.

[0012] In the above-mentioned low-cost, high-performance aluminum alloy monofilament, preferably, in the preparation step of the low-cost, high-performance aluminum alloy monofilament, the raw materials used include aluminum ingots and iron agents, etc.

[0013] In the above-mentioned low-cost, high-performance aluminum alloy monofilament, preferably, in the preparation step of the low-cost, high-performance aluminum alloy monofilament, the smelting includes: adding aluminum ingots and iron agent into the smelting furnace according to the elemental composition and weight percentage of the low-cost, high-performance aluminum alloy monofilament, heating and melting, and fully stirring.

[0014] In the above-mentioned low-cost, high-performance aluminum alloy monofilament, preferably, in the step of preparing the low-cost, high-performance aluminum alloy monofilament, the refining includes furnace refining and online refining;

[0015] The furnace refining includes: transferring the melt obtained by smelting to a tilting holding furnace, turning on 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 furnace refining for 10-15 minutes, then thoroughly scraping off the slag on the surface of the melt, then adjusting the melt temperature to 720-730°C, and letting it stand for 30-40 minutes;

[0016] The online refining includes: after the casting starts, online degassing and online filtering of the melt; wherein, the online degassing adopts a rotary spray degassing box; and the online filtration adopts a double-stage foam ceramic filter box.

[0017] In the above-mentioned low-cost, high-performance aluminum alloy monofilament, preferably, in the step of preparing the low-cost, high-performance aluminum alloy monofilament, the melt after the ultrasonic treatment contains Al3Fe phase and Al6Fe phase.

[0018] In the above-mentioned low-cost, high-performance aluminum alloy monofilament, preferably, in the step of preparing the low-cost, high-performance aluminum alloy monofilament, the average grain size of the ingot is less than 50 μm.

[0019] In the above-mentioned low-cost, high-performance aluminum alloy monofilament, preferably, in the preparation step of the low-cost, high-performance aluminum alloy monofilament, the continuous rolling mill group adopts a three-roll mill; more preferably, the continuous rolling mill group adopts a 15-stand three-roll mill.

[0020] In the above-mentioned low-cost, high-performance aluminum alloy monofilament, preferably, in the step of preparing the low-cost, high-performance aluminum alloy monofilament, the diameter of the aluminum alloy rod is 9-10 mm.

[0021] The present invention uses ultrasonic treatment on the refined melt to create localized undercooling zones within the melt through cavitation, prompting the precipitation of large amounts of Fe as fine Al3Fe and Al6Fe phases. This refines the grain structure during casting, resulting in an average grain size of less than 50 μm in the ingot, preventing the formation of coarse, needle-like, iron-rich phases in the alloy and improving its plasticity. Furthermore, the present invention maintains a high alloy temperature throughout the rolling process and air-cools the rod after rolling, utilizing residual heat to promote the precipitation of small amounts of Fe in solution.

[0022] In the above-mentioned low-cost, high-performance aluminum alloy monofilament, preferably, in the preparation step of the low-cost, high-performance aluminum alloy monofilament, the rod drawing includes: using a sliding wire drawing machine to draw the aluminum alloy rod to obtain the low-cost, high-performance aluminum alloy monofilament.

[0023] According to a specific embodiment of the present invention, preferably, the diameter of the low-cost, high-performance aluminum alloy monofilament is 2.5-4 mm.

[0024] According to a specific embodiment of the present invention, preferably, the low-cost, high-performance aluminum alloy single wire has a strength of ≥280 MPa, a conductivity of ≥59% IACS, and an elongation of ≥3%.

[0025] A second aspect of the present invention provides a method for preparing the aforementioned low-cost, high-performance aluminum alloy monofilament, comprising the following steps: subjecting raw materials to at least smelting, refining, ultrasonic treatment, continuous casting and rolling, and rod drawing according to the elemental composition and weight percentage of the low-cost, high-performance aluminum alloy monofilament, to prepare the low-cost, high-performance aluminum alloy monofilament;

[0026] The ultrasonic treatment comprises: performing online ultrasonic treatment on the refined melt, with an ultrasonic power of 2-5Kw and a frequency of 1.8-2.5KHz;

[0027] The continuous casting and rolling process includes: pouring the ultrasonically treated melt into a wheel-type crystallizer for continuous casting to form a billet, which is then continuously rolled in a continuous rolling mill. Before rolling, a medium-frequency heating device is used to heat the billet, the rolling entry temperature is controlled to be 530-550° C., the emulsion preheating temperature 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 the aluminum alloy rod is obtained after rolling.

[0028] In the above-mentioned preparation method, preferably, the raw materials used include aluminum ingots and iron agents.

[0029] In the above preparation method, preferably, the smelting includes: adding aluminum ingots and iron agent into a smelting furnace according to the element composition and weight percentage of the low-cost, high-performance aluminum alloy monofilament, heating and melting, and fully stirring.

[0030] In the above preparation method, preferably, the refining includes furnace refining and online refining;

[0031] The furnace refining includes: transferring the melt obtained by smelting to a tilting holding furnace, turning on 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 furnace refining for 10-15 minutes, then thoroughly scraping off the slag on the surface of the melt, then adjusting the melt temperature to 720-730°C, and letting it stand for 30-40 minutes;

[0032] The online refining includes: after the casting starts, online degassing and online filtering of the melt; wherein, the online degassing adopts a rotary spray degassing box; and the online filtration adopts a double-stage foam ceramic filter box.

[0033] In some specific embodiments of the present invention, preferably, the degassing medium of the rotary jet degassing box is high-purity nitrogen, the rotation speed of the graphite rotor is 400-500 rpm, and the hydrogen content in the melt can be reduced to <0.12 ml / 100 g through online degassing.

[0034] In some specific embodiments of the present invention, preferably, the porosity of the dual-stage foam ceramic filter box is 30 / 50 PPI. The dual-stage foam ceramic filter box includes two layers of foam ceramic filter plates. The first layer of filter plates has a larger pore size (30 PPI) and mainly filters large-sized inclusions. The second layer of filter plates has a smaller pore size (50 PPI) and filters small-sized inclusions. The dual-stage filtration has the advantages of a wider filtration range and higher filtration accuracy. The dual-stage foam ceramic filter box with a porosity of 30 / 50 PPI used in the present invention can better remove 5-10 μm inclusion particles in the melt and reduce the adverse effects of inclusions on the elongation of alloy monofilaments.

[0035] In the above preparation method, preferably, the melt after the ultrasonic treatment contains Al3Fe phase and Al6Fe phase.

[0036] In the above preparation method, preferably, the average grain size of the ingot is less than 50 μm.

[0037] In the above-mentioned preparation method, preferably, the continuous rolling mill group adopts a three-roll rolling mill; more preferably, the continuous rolling mill group adopts a three-roll rolling mill with 15 stands.

[0038] In the above preparation method, preferably, the diameter of the aluminum alloy rod is 9-10 mm.

[0039] According to a specific embodiment of the present invention, during the continuous casting and rolling process, the equipment used for continuous casting and continuous rolling can be equipment in the prior art, and the emulsion used can be a conventional emulsion in aluminum alloy continuous rolling technology.

[0040] In the above preparation method, preferably, the rod drawing includes: drawing the aluminum alloy rod with a sliding wire drawing machine to obtain an aluminum alloy monofilament with a diameter of 2.5-4 mm, which is the low-cost, high-performance aluminum alloy monofilament.

[0041] The present invention provides a low-cost, high-performance aluminum alloy monofilament and a method for preparing the same. The aluminum alloy monofilament provided by the present invention is a low-cost, high-conductivity, medium-strength aluminum alloy monofilament with a strength of 280 MPa or higher, a conductivity of 59% IACS or higher, and an elongation of 3% or higher. The preparation process can meet the requirements of mass production.

[0042] The technical solution of the present invention has at least the following beneficial effects:

[0043] (1) The alloy element composition of the present invention basically contains only Fe element in addition to Al element, so the cost of the alloy material is extremely low, and the solid solubility of Fe element in the matrix is ​​very small, so it has little effect on the conductive properties of the alloy, and can make the alloy achieve very high conductivity.

[0044] (2) The present invention utilizes online ultrasonic treatment to form a large amount of Fe elements in the melt into submicron-scale, fine and regular Al3Fe and Al6Fe precipitation phases, which can enable the alloy to obtain very high strength and minimize its adverse effects on plasticity; at the same time, the fine iron-containing phase produces an excellent grain refining effect during solidification, making the average cast grain size less than 50μm.

[0045] (3) The preparation process of the aluminum alloy monofilament of the present invention is simple, does not require long-term aging treatment, has low energy consumption, high production efficiency, and does not require the addition of additional grain refiners, thereby further reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] FIG1 is a diagram showing the as-cast grain structure of the ingot in Example 1. DETAILED DESCRIPTION

[0047] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0048] According to a specific embodiment of the present invention, the low-cost, high-performance aluminum alloy monofilament provided by the present invention includes the following elemental composition, in terms of weight percentage: Fe0.8-1.5%, Si≤0.05%, and 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%.

[0049] According to a specific embodiment of the present invention, the process of the method for preparing low-cost, high-performance aluminum alloy monofilament provided by the present invention is as follows:

[0050] Melting → furnace refining → standing → casting → online degassing → online filtration → ultrasonic treatment → continuous casting and rolling → rod drawing.

[0051] Specifically, the method for preparing low-cost, high-performance aluminum alloy monofilament provided by the present invention comprises the following steps:

[0052] (1) Aluminum smelting

[0053] According to the element composition and weight percentage of the low-cost, high-performance aluminum alloy monofilament, an aluminum ingot with a purity greater than 99.7% and an iron agent are added to a smelting furnace, heated and melted, and the molten aluminum liquid is thoroughly stirred;

[0054] (2) Furnace refining

[0055] Transfer the melt in the smelting furnace to the 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℃ and conduct furnace refining for 10-15 minutes, then completely scrape off the slag on the surface of the melt, then adjust the melt temperature to 720-730℃ and let it stand for 30-40 minutes;

[0056] (3) Online refining

[0057] After casting begins, the melt is degassed and filtered online. The online degassing uses a rotary jet degassing box with high-purity nitrogen as the degassing medium and the graphite rotor speed is 400-500r / min. The online filtration uses a two-stage foam ceramic filter box with a porosity of 30 / 50PPI to remove 5-10μm inclusion particles in the melt and reduce the adverse effects of inclusions on the elongation of the alloy single wire.

[0058] (4) Ultrasonic treatment

[0059] The refined melt is subjected to online ultrasonic treatment in the launder, with an ultrasonic power of 2-5 kW and a frequency of 1.8-2.5 kHz. This creates a localized supercooling 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. This refines the grain structure in the subsequent casting process, prevents the formation of coarse, needle-like iron-rich phases in the alloy, and improves the alloy's plasticity.

[0060] (5) Continuous casting and rolling

[0061] The ultrasonically treated melt is poured into a wheel-type crystallizer for continuous casting to form a billet with an average grain size of less than 50 μm. The billet is then continuously rolled in a continuous rolling mill. The continuous rolling mill uses a 15-stand three-roll mill. A medium-frequency heating device is used to heat the billet before rolling. The rolling temperature is controlled at 530-550°C, the emulsion preheating temperature is adjusted at 40-60°C, the emulsion flow rate is 120-180 L / min, and the final rolling temperature is above 350°C. This allows the alloy to maintain a high temperature throughout the rolling process, promoting the precipitation of a small amount of Fe in solid solution in the alloy. After rolling, the rod is air-cooled to obtain an aluminum alloy rod with a diameter of 9-10 mm.

[0062] (6) Rod drawing

[0063] The aluminum alloy rod is drawn 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.

[0064] Example 1

[0065] This embodiment provides a low-cost, high-performance aluminum alloy monofilament, which is prepared by the following steps:

[0066] (1) According to the element composition and weight percentage of the designed aluminum alloy monofilament, add aluminum ingots with a purity greater than 99.7% and iron agent into the melting furnace, heat and melt, and stir the molten aluminum liquid thoroughly;

[0067] (2) The melt in the smelting 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 furnace refining for 12 minutes, and then the slag on the surface of the melt is completely scraped off. After that, the temperature of the melt is adjusted to 723°C and allowed to stand for 30 minutes;

[0068] (3) After casting begins, the melt is degassed and filtered online. The online degassing uses a rotary jet degassing box with high-purity nitrogen as the degassing medium and the graphite rotor speed is 450 r / min. The online filtration uses a two-stage foam ceramic filter box with a porosity of 30 / 50 PPI to remove 5-10 μm inclusion particles in the melt and reduce the adverse effects of inclusions on the elongation of the alloy single wire.

[0069] (4) The refined melt is subjected to online ultrasonic treatment in the launder, with an ultrasonic power of 3 kW and a frequency of 2.2 kHz. A local supercooling zone is formed in the melt through the cavitation effect, which promotes the precipitation of a large amount of Fe elements in the form of fine Al3Fe and Al6Fe phases, refines the grain structure, and prevents the formation of coarse needle-shaped iron-rich phases in the alloy, thereby improving the alloy plasticity.

[0070] (5) The melt after ultrasonic treatment is poured into a wheel 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 15-stand three-roll mill for continuous rolling. Before rolling, a medium-frequency heating device is used to heat the billet, and the rolling temperature is controlled to be 540°C. The emulsion preheating temperature is adjusted to 40°C, the emulsion flow rate is 150 L / min, and the final rolling temperature is above 350°C. The alloy is kept at a high temperature throughout the rolling process to promote the precipitation of a small amount of Fe element in the solid solution state in the alloy. After rolling, the rod is air-cooled to obtain an aluminum alloy rod with a diameter of 9.5 mm.

[0071] (6) The aluminum alloy rod is drawn on a sliding wire drawing machine to obtain an aluminum alloy monofilament with a diameter of 3.5 mm, which is the low-cost and high-performance aluminum alloy monofilament.

[0072] After analysis and testing, the elemental composition of the low-cost, high-performance aluminum alloy monofilament of this embodiment is, in terms of weight percentage, Fe0.94%, Si0.05%, and the remainder 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%.

[0073] The low-cost, high-performance aluminum alloy monofilament provided in this embodiment has an average strength of 283 MPa, an elongation of 3.5%, and a conductivity of 59.7% IACS.

[0074] Example 2

[0075] This embodiment provides a low-cost, high-performance aluminum alloy monofilament, which is prepared by the following steps:

[0076] (1) According to the element composition and weight percentage of the designed aluminum alloy monofilament, add aluminum ingots with a purity greater than 99.7% and iron agent into the melting furnace, heat and melt, and stir the molten aluminum liquid thoroughly;

[0077] (2) The melt in the smelting 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 furnace refining for 15 minutes, and then the slag on the surface of the melt is thoroughly scraped off. After that, the temperature of the melt is adjusted to 720°C and allowed to stand for 30 minutes;

[0078] (3) After casting begins, the melt is degassed and filtered online. The online degassing uses a rotary jet degassing box with high-purity nitrogen as the degassing medium and the graphite rotor speed is 450 r / min. The online filtration uses a two-stage foam ceramic filter box with a porosity of 30 / 50 PPI to remove 5-10 μm inclusion particles in the melt and reduce the adverse effects of inclusions on the elongation of the alloy single wire.

[0079] (4) The refined melt is subjected to online ultrasonic treatment in the launder, with an ultrasonic power of 3 kW and a frequency of 2.2 kHz. A local supercooling zone is formed in the melt through the cavitation effect, which promotes the precipitation of a large amount of Fe elements in the form of fine Al3Fe and Al6Fe phases, refines the grain structure, and prevents the formation of coarse needle-shaped iron-rich phases in the alloy, thereby improving the alloy plasticity.

[0080] (5) The melt after ultrasonic treatment is poured into a wheel crystallizer for continuous casting to form a billet. The average grain size of the billet is less than 50 μm. The billet enters a 15-stand three-roll mill for continuous rolling. Before rolling, a medium-frequency heating device is used to heat the billet. The rolling temperature is controlled to be 545°C, the emulsion preheating temperature is adjusted to 40°C, the emulsion flow rate is 150 L / min, and the final rolling temperature is above 350°C. The alloy is kept at a high temperature throughout the rolling process to promote the precipitation of a small amount of Fe element in the solid solution state in the alloy. After rolling, the rod is air-cooled to obtain an aluminum alloy rod with a diameter of 9.5 mm.

[0081] (6) The aluminum alloy rod is drawn on a sliding wire drawing machine to obtain an aluminum alloy monofilament with a diameter of 3.8 mm, which is the low-cost and high-performance aluminum alloy monofilament.

[0082] After analysis and testing, the elemental composition of the low-cost, high-performance aluminum alloy monofilament of this embodiment is, in terms of weight percentage, Fe1.06%, Si0.05%, and the remainder 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%.

[0083] The low-cost, high-performance aluminum alloy monofilament provided in this embodiment has an average strength of 288 MPa, an elongation of 3.3%, and a conductivity of 59.4% IACS.

[0084] Example 3

[0085] This embodiment provides a low-cost, high-performance aluminum alloy monofilament, which is prepared by the following steps:

[0086] (1) According to the element composition and weight percentage of the designed aluminum alloy monofilament, add aluminum ingots with a purity greater than 99.7% and iron agent into the melting furnace, heat and melt, and stir the molten aluminum liquid thoroughly;

[0087] (2) The melt in the smelting 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 furnace refining for 15 minutes, and then the slag on the surface of the melt is thoroughly scraped off. After that, the temperature of the melt is adjusted to 720°C and allowed to stand for 30 minutes;

[0088] (3) After casting begins, the melt is degassed and filtered online. The online degassing uses a rotary jet degassing box with high-purity nitrogen as the degassing medium and the graphite rotor speed is 450 r / min. The online filtration uses a two-stage foam ceramic filter box with a porosity of 30 / 50 PPI to remove 5-10 μm inclusion particles in the melt and reduce the adverse effects of inclusions on the elongation of the alloy single wire.

[0089] (4) The refined melt is subjected to online ultrasonic treatment in the launder, with an ultrasonic power of 3 kW and a frequency of 2.2 kHz. A local supercooling zone is formed in the melt through the cavitation effect, which promotes the precipitation of a large amount of Fe elements in the form of fine Al3Fe and Al6Fe phases, refines the grain structure, prevents the formation of coarse needle-shaped iron-rich phases in the alloy, and improves the plasticity of the alloy;

[0090] (5) The melt after ultrasonic treatment is poured into a wheel crystallizer for continuous casting to form a billet. The average grain size of the billet is less than 50 μm. The billet enters a 15-stand three-roll rolling mill for continuous rolling. Before rolling, a medium-frequency heating device is used to heat the billet. The rolling temperature is controlled to be 545°C, the emulsion preheating temperature is adjusted to 50°C, the emulsion flow rate is 150 L / min, and the final rolling temperature is above 350°C. The alloy is kept at a high temperature throughout the rolling process to promote the precipitation of a small amount of Fe element in the solid solution state in the alloy. After rolling, the rod is air-cooled to obtain an aluminum alloy rod with a diameter of 9.5 mm.

[0091] (6) The aluminum alloy rod is drawn on a sliding wire drawing machine to obtain an aluminum alloy monofilament with a diameter of 3.8 mm, which is the low-cost and high-performance aluminum alloy monofilament.

[0092] After analysis and testing, the elemental composition of the low-cost, high-performance aluminum alloy monofilament of this embodiment is, in terms of weight percentage, Fe1.15%, Si0.04%, and the remainder 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%.

[0093] The low-cost, high-performance aluminum alloy monofilament provided in this embodiment has an average strength of 295 MPa, an elongation of 3.1%, and a conductivity of 59% IACS.

[0094] Comparative Example 1

[0095] This comparative example provides an aluminum alloy monofilament, which is prepared by the following steps:

[0096] (1) According to the element composition and weight percentage of the designed aluminum alloy monofilament, add aluminum ingots with a purity greater than 99.7% and iron agent into the melting furnace, heat and melt, and stir the molten aluminum liquid thoroughly;

[0097] (2) The melt in the smelting 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 furnace refining for 15 minutes, and then the slag on the surface of the melt is thoroughly scraped off. After that, the temperature of the melt is adjusted to 720°C and allowed to stand for 30 minutes;

[0098] (3) After casting begins, the melt is degassed and filtered online. The online degassing uses a rotary jet degassing box with high-purity nitrogen as the degassing medium and the graphite rotor speed is 450 r / min. The online filtration uses a two-stage foam ceramic filter box with a porosity of 30 / 50 PPI to remove 5-10 μm inclusion particles in the melt and reduce the adverse effects of inclusions on the elongation of the alloy single wire.

[0099] (4) The melt after online filtration is poured into a wheel crystallizer for continuous casting to form a billet, which is then continuously rolled in a 15-stand three-roll mill. Before rolling, the billet is heated by a medium frequency heating device, the rolling temperature is controlled at 500°C, the emulsion preheating temperature is adjusted at 30°C, the emulsion flow rate is 250 L / min, the final rolling temperature is above 350°C, and the rod is air-cooled after rolling to obtain an aluminum alloy rod with a diameter of 9.5 mm.

[0100] (5) The aluminum alloy rod is drawn on a sliding wire drawing machine to obtain an aluminum alloy single wire with a diameter of 3.5 mm.

[0101] After analysis and testing, the element composition of the aluminum alloy monofilament of this comparative example is, in weight percentage, Fe1.02%, Si0.05%, and 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%.

[0102] The aluminum alloy monofilament provided in this comparative example has an average strength of 275 MPa, an elongation of 1.3%, and an electrical conductivity of 58.4% IACS.

[0103] Comparative Example 2

[0104] This comparative example provides an aluminum alloy monofilament, which is prepared by the following steps:

[0105] (1) According to the element composition and weight percentage of the designed aluminum alloy monofilament, add aluminum ingots with a purity greater than 99.7% and iron agent into the melting furnace, heat and melt, and stir the molten aluminum liquid thoroughly;

[0106] (2) The melt in the smelting 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 furnace refining for 15 minutes, and then the slag on the surface of the melt is thoroughly scraped off. After that, the temperature of the melt is adjusted to 720°C and allowed to stand for 30 minutes;

[0107] (3) After casting begins, the melt is degassed and filtered online. The online degassing uses a rotary jet degassing box with high-purity nitrogen as the degassing medium and the graphite rotor speed is 450 r / min. The online filtration uses a two-stage foam ceramic filter box with a porosity of 30 / 50 PPI to remove 5-10 μm inclusion particles in the melt and reduce the adverse effects of inclusions on the elongation of the alloy single wire.

[0108] (4) The refined melt was subjected to online ultrasonic treatment in the launder, with an ultrasonic power of 3 kW and a frequency of 2.2 kHz;

[0109] (5) The ultrasonically treated melt is poured into a wheel-type crystallizer for continuous casting to form a billet, which is then continuously rolled in a 15-stand three-roll rolling mill. Before rolling, a medium-frequency heating device is used to heat the billet, controlling the rolling temperature to 550°C, adjusting the emulsion preheating temperature to 40°C, the emulsion flow rate to 150 L / min, and the final rolling temperature to above 350°C. After rolling, the rod is air-cooled to obtain an aluminum alloy rod with a diameter of 9.5 mm.

[0110] (6) The aluminum alloy rod is drawn on a sliding wire drawing machine to obtain an aluminum alloy single wire with a diameter of 3.5 mm.

[0111] After analysis and testing, the element composition of the aluminum alloy monofilament of this comparative example is, by weight percentage, Fe0.57%, Si0.05%, and the remainder 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%.

[0112] The aluminum alloy monofilament provided in this comparative example has an average strength of 246 MPa, an elongation of 3.7%, and an electrical conductivity of 60.2% IACS.

[0113] Comparative Example 3

[0114] This comparative example provides an aluminum alloy monofilament, which is prepared by the following steps:

[0115] (1) According to the element composition and weight percentage of the designed aluminum alloy monofilament, 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, and magnesium ingots are added to the aluminum liquid and stirred and melted, and the molten aluminum liquid is fully stirred;

[0116] (2) The melt in the smelting 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 furnace refining for 15 minutes, and then the slag on the surface of the melt is thoroughly scraped off, and then the temperature of the melt is adjusted to 730°C and left to stand for 30 minutes;

[0117] (3) After casting begins, the melt is degassed and filtered online. The online degassing uses a rotary jet degassing box with high-purity nitrogen as the degassing medium and the graphite rotor speed is 450 r / min. The online filtration uses a two-stage foam ceramic filter box with a porosity of 30 / 50 PPI to remove 5-10 μm inclusion particles in the melt and reduce the adverse effects of inclusions on the elongation of the alloy single wire.

[0118] (4) When the melt flows through the launder, aluminum titanium boron refiner is added online for grain refinement. The amount of refiner added is 0.08% based on the total weight of the melt as 100%;

[0119] (5) The melt is poured into a wheel-type crystallizer for continuous casting to form a billet, which is then continuously rolled in a 15-stand three-roll rolling mill. Before rolling, the billet is heated by a medium-frequency heating device, the rolling temperature is controlled to be 500°C, the emulsion preheating temperature is adjusted to 30°C, the emulsion flow rate is 250L / min, and the final rolling temperature is above 350°C. After rolling, an aluminum alloy rod with a diameter of 9.5 mm is obtained, which is then quenched with online cooling water and then collected;

[0120] (6) Drawing the aluminum alloy rod on a sliding wire drawing machine to obtain an aluminum alloy monofilament with a diameter of 3.5 mm;

[0121] (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 an aluminum alloy single wire.

[0122] After analysis and testing, the element composition of the aluminum alloy monofilament of this comparative example is, by weight percentage, Mg 0.38%, Si 0.35%, Fe 0.14%, La 0.01%, B 0.004%, Ti 0.002, and the remainder 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%.

[0123] The aluminum alloy monofilament provided in this comparative example has an average strength of 264 MPa, an elongation of 5.3%, and an electrical conductivity of 58.2% IACS.

[0124] In summary, the aluminum alloy monofilaments provided by Examples 1-3 of the present invention are low-cost, high-conductivity, and medium-strength aluminum alloy monofilaments, with a single-filament strength ≥280 MPa, a conductivity ≥59% IACS, and an elongation ≥3%. Their preparation process routes meet the requirements of mass production. However, the aluminum alloy monofilaments obtained in Comparative Examples 1-3, whose elemental compositions fall outside the range defined by the present invention or whose preparation processes differ from those of the present invention, exhibit inferior overall performance.

Claims

1. 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 elements: Fe 0.8-1.5%, Si ≤ 0.05%, the balance is Al and inevitable impurity elements.

2. The low-cost, high-performance aluminum alloy monofilament according to claim 1, wherein: Taking the total weight of the low-cost, high-performance aluminum alloy monofilament as 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, high-performance aluminum alloy monofilament according to claim 1 or 2, wherein: The low-cost, high-performance aluminum alloy monofilament is prepared by at least the following steps: according to the element composition and weight percentage of the low-cost, high-performance aluminum alloy monofilament, the raw material is at least smelted, refined, ultrasonically treated, continuously cast and rolled, and rod drawn to prepare the low-cost, high-performance aluminum alloy monofilament; The ultrasonic treatment comprises: performing online ultrasonic treatment on the refined melt, with an ultrasonic power of 2-5Kw and a frequency of 1.8-2.5KHz; The continuous casting and rolling process comprises: pouring the ultrasonically treated melt into a wheel-type crystallizer for continuous casting to form a cast billet, the cast billet entering a continuous rolling unit for continuous rolling, heating the cast billet with a medium frequency heating device before rolling, controlling the rolling temperature to be 530-550° C., adjusting the emulsion preheating temperature to be 40-60° C., the emulsion flow rate to be 120-180 L / min, and the final rolling temperature to be above 350° C., and obtaining an aluminum alloy rod after rolling.

4. The low-cost, high-performance aluminum alloy monofilament according to claim 3, wherein: The melt after the ultrasonic treatment contains Al3Fe phase and Al6Fe phase.

5. The low-cost, high-performance aluminum alloy monofilament according to claim 3, wherein: The average grain size of the ingot is less than 50 μm.

6. The low-cost, high-performance aluminum alloy monofilament according to claim 1, wherein: The diameter of the low-cost, high-performance aluminum alloy monofilament is 2.5-4 mm.

7. The low-cost, high-performance aluminum alloy monofilament according to claim 1, wherein: The low-cost, high-performance aluminum alloy single wire has a strength of ≥280 MPa, a conductivity of ≥59% IACS, and an elongation of ≥3%.

8. A method for preparing a low-cost, high-performance aluminum alloy monofilament according to any one of claims 1 to 7, comprising the following steps: According to the element composition and weight percentage of the low-cost, high-performance aluminum alloy monofilament, the raw material is at least smelted, refined, ultrasonically treated, continuously cast and rolled, and rod drawn to prepare the low-cost, high-performance aluminum alloy monofilament; The ultrasonic treatment comprises: performing online ultrasonic treatment on the refined melt, with an ultrasonic power of 2-5Kw and a frequency of 1.8-2.5KHz; The continuous casting and rolling process comprises: pouring the ultrasonically treated melt into a wheel-type crystallizer for continuous casting to form a cast billet, the cast billet entering a continuous rolling unit for continuous rolling, heating the cast billet with a medium frequency heating device before rolling, controlling the rolling temperature to be 530-550° C., adjusting the emulsion preheating temperature to be 40-60° C., the emulsion flow rate to be 120-180 L / min, and the final rolling temperature to be above 350° C., and obtaining an aluminum alloy rod after rolling.

9. The preparation method according to claim 8, wherein: The smelting comprises: adding aluminum ingots and iron agent into a smelting furnace according to the element composition and weight percentage of the low-cost high-performance aluminum alloy monofilament, heating and melting, and fully stirring; Preferably, the refining includes furnace refining and online refining; the furnace refining includes: transferring the melt obtained by smelting to a tilting insulation furnace, turning on the electromagnetic stirring device at the bottom of the tilting insulation furnace to fully stir the melt, adjusting the melt temperature to 730-750°C for furnace refining for 10-15 minutes, and then completely scraping off 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 online refining includes: after the casting starts, online degassing and online filtering of the melt; wherein the online degassing adopts a rotary spray degassing box; the online filtration adopts a double-stage foam ceramic filter box; Preferably, the degassing medium of the rotary jet degassing box is high-purity nitrogen, and the rotation speed of the graphite rotor is 400-500r / min; Preferably, the porosity of the dual-stage foam ceramic filter box is 30 / 50 PPI.

10. The preparation method according to claim 8, wherein: The continuous rolling mill group adopts a three-roll rolling mill; preferably, the continuous rolling mill group adopts a 15-frame three-roll rolling mill; Preferably, the diameter of the aluminum alloy rod is 9-10 mm.

11. The preparation method according to claim 8, wherein: The rod drawing comprises: drawing the aluminum alloy rod by 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.

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