Aluminum alloy wire and its preparation method and application

Abstract

The present invention provides an aluminum alloy wire and its preparation method and application, the preparation method includes batching, smelting, casting, rotary forging, hot extrusion, hot drawing, cold drawing and cryogenic treatment in sequence; wherein the materials used in the batching include pure aluminum ingots and intermediate alloys, and the purity of the pure aluminum ingots is ≥99.7wt%; the casting, rotary forging, hot extrusion and hot drawing are followed by annealing treatments independently; the heating processes of the hot extrusion and hot drawing are independently carried out in a medium frequency induction coil; the cooling process of the cold drawing and the cryogenic treatment are independently carried out in a liquid nitrogen tank. The preparation method provided by the present invention improves the uniformity and density of the material, and the obtained aluminum alloy wire achieves the effects of high strength, bending resistance, and high / low temperature resistance, which is conducive to large-scale promotion and application.

Description

Technical Field

[0001] The invention belongs to the technical field of wire preparation, and relates to an aluminum alloy wire, and in particular to an aluminum alloy wire and a preparation method and application thereof. Background Art

[0002] Aluminum alloy wires are wires made of aluminum alloys. They are widely used in various fields such as automobiles, electricity, electronics, machinery, and construction because of their excellent mechanical properties, corrosion resistance, high specific strength, and electrical conductivity. At present, the application market requires aluminum alloy wires to have high strength, bending resistance, and high / low temperature resistance. This requires the wires to have high mechanical properties in complex environments and to be able to provide good service in actual working conditions such as wide temperature ranges and heavy loads.

[0003] The most common processing method for preparing aluminum alloy wires is drawing. By controlling the process conditions of drawing, aluminum alloy wires of various shapes, sizes and properties can be prepared. In recent years, the most widely used aluminum alloy wires in the industry are 6xxx series alloy wires, but the lower strength and corrosion resistance of this type of wire limit its application in the automotive, power and other fields. With the rapid development of new energy vehicles, high-voltage power transmission and other fields, the development of high-strength, bending-resistant, high / low temperature resistant aluminum alloy wires has become increasingly important.

[0004] CN107017036A discloses a high-strength graphene rare earth aluminum alloy wire. In addition to graphene and aluminum matrix, as many as 14 alloy elements are added. Since graphene is not only easily oxidized when added to molten metal, but also difficult to dissolve into the alloy, extremely high requirements are placed on the smelting equipment and smelting process. In addition, the invention does not explain how to add graphene to molten aluminum, nor does it explain the processing process after smelting.

[0005] CN105671374A discloses a method for preparing a highly conductive and heat-resistant aluminum alloy conductor. In the method, the aluminum liquid is directly solidified in a launder, which not only easily mixes with impurities during the casting process, but also fails to ensure the uniformity and density of the material structure, ultimately resulting in a large room for improvement in the performance of the obtained material.

[0006] It can be seen that how to provide an aluminum alloy wire and a preparation method thereof to improve the material's organizational uniformity and density and achieve high strength, bending resistance, and high / low temperature resistance has become an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0007] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an aluminum alloy wire and a preparation method and application thereof. The preparation method improves the organizational uniformity and density of the material, and the obtained aluminum alloy wire achieves the effects of high strength, bending resistance, and high / low temperature resistance, which is conducive to large-scale promotion and application.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing an aluminum alloy wire, the method comprising batching, smelting, casting, rotary forging, hot extrusion, hot drawing, cold drawing and cryogenic treatment performed in sequence.

[0010] Among them, the materials used in the formulation include pure aluminum ingots and intermediate alloys, and the purity of the pure aluminum ingots is ≥99.7wt%, for example, it can be 99.7wt%, 99.75wt%, 99.8wt%, 99.85wt%, 99.9wt% or 99.95wt%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0011] The casting, rotary forging, hot extrusion and hot drawing are then followed by annealing treatments respectively and independently.

[0012] The heating processes of hot extrusion and hot drawing are respectively and independently carried out in medium frequency induction coils.

[0013] The cooling process of the cold drawing and the cryogenic treatment are carried out independently in a liquid nitrogen tank.

[0014] The preparation method provided by the present invention achieves full refinement of aluminum alloy grains through rotary forging, hot extrusion and hot drawing, obtains fine-grained structure, and improves the structural uniformity and density of the material; the morphology and distribution of defects such as dislocations and stacking faults in the wire are regulated through cold drawing and deep cryogenic treatment, thereby improving the mechanical properties of the aluminum alloy wire; the synergistic cooperation between the above-mentioned processing processes finally realizes the construction of multiple heterogeneous structures, obtains aluminum alloy wires with excellent service performance, achieves the effects of high strength, bending resistance, and high / low temperature resistance, and is conducive to large-scale promotion and application.

[0015] Preferably, the intermediate alloy comprises any one of aluminum-magnesium alloy, aluminum-silicon alloy, aluminum-copper alloy, aluminum-chromium alloy or aluminum-zirconium alloy, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of aluminum-magnesium alloy and aluminum-silicon alloy, a combination of aluminum-silicon alloy and aluminum-copper alloy, a combination of aluminum-copper alloy and aluminum-chromium alloy, a combination of aluminum-chromium alloy and aluminum-zirconium alloy, a combination of aluminum-magnesium alloy, aluminum-silicon alloy and aluminum-copper alloy, a combination of aluminum-silicon alloy, aluminum-copper alloy and aluminum-chromium alloy, or a combination of aluminum-copper alloy, aluminum-chromium alloy and aluminum-zirconium alloy. Further preferred is a combination of aluminum-magnesium alloy, aluminum-silicon alloy, aluminum-copper alloy, aluminum-chromium alloy and aluminum-zirconium alloy.

[0016] Preferably, the smelting comprises: firstly heating the pure aluminum ingot to melt, then adding the intermediate alloy and stirring, after all the alloys are melted, using an inert gas to spray a refining agent into the obtained aluminum alloy liquid, continuing to stir, then standing and removing slag.

[0017] Preferably, the smelting is carried out in a regenerative gas-fired aluminum melting furnace, and the set temperature is 730-750°C, for example, it can be 730°C, 732°C, 734°C, 736°C, 738°C, 740°C, 742°C, 744°C, 746°C, 748°C or 750°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] Preferably, the inert gas comprises helium and / or argon.

[0019] Preferably, the refining agent includes sodium nitrate and graphite, and the amount of the refining agent is 0.12%-0.15% of the total mass of the aluminum alloy liquid, for example, it can be 0.12%, 0.125%, 0.13%, 0.135%, 0.14%, 0.145% or 0.15%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] In the present invention, the refining agent generates gas insoluble in the aluminum alloy melt in a high temperature environment, thereby achieving the purpose of purifying the aluminum alloy melt.

[0021] Preferably, the casting comprises: preheating the mold first, and then casting the aluminum alloy liquid into a round rod-shaped aluminum billet in the mold.

[0022] Preferably, the preheating temperature of the mold is 250-350°C, for example, it can be 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C or 350°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, the casting temperature of the aluminum alloy liquid is 700-710°C, for example, it can be 700°C, 701°C, 702°C, 703°C, 704°C, 705°C, 706°C, 707°C, 708°C, 709°C or 710°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, the cooling rate of the aluminum alloy liquid is 30-100℃ / s, for example, it can be 30℃ / s, 35℃ / s, 40℃ / s, 45℃ / s, 50℃ / s, 55℃ / s, 60℃ / s, 65℃ / s, 70℃ / s, 75℃ / s, 80℃ / s, 85℃ / s, 90℃ / s, 95℃ / s or 100℃ / s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0025] Preferably, the specification of the round rod-shaped aluminum billet is For example it could be

[0026] or However, it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, homogenization annealing is performed after the casting to make the chemical composition of the aluminum billet uniform and eliminate internal stress, and the annealing temperature is 470-500°C, for example, it can be 470°C, 475°C, 480°C, 485°C, 490°C, 495°C or 500°C, and the annealing time is 2-12h, for example, it can be 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h or 12h, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the rotary forging comprises: firstly heating the aluminum billet, and then rotary forging the aluminum billet into an aluminum rod.

[0029] Preferably, the heating temperature of the aluminum billet is 500-580°C, for example, it can be 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C or 580°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, the feed rate of the rotary forging is 2-9 mm / min, for example, it can be 2 mm / min, 2.5 mm / min, 3 mm / min, 3.5 mm / min, 4 mm / min, 4.5 mm / min, 5 mm / min, 5.5 mm / min, 6 mm / min, 6.5 mm / min, 7 mm / min, 7.5 mm / min, 8 mm / min, 8.5 mm / min or 9 mm / min, and the rotation speed is 30-240 r / min, for example, it can be 30 r / min, 40 r / min, 60 r / min, 80 r / min, 100 r / min, 120 r / min, 140 r / min, 160 r / min, 180 r / min, 200 r / min, 220 r / min or 240 r / min, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] Preferably, the specification of the aluminum rod is For example it could be or However, it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, stress relief annealing is performed after the rotary forging to eliminate the internal stress of the aluminum rod, and the annealing temperature is 270-300°C, for example, it can be 270°C, 275°C, 280°C, 285°C, 290°C, 295°C or 300°C, and the annealing time is 3-5h, for example, it can be 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h or 5h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] Preferably, the hot extrusion comprises: firstly heating the aluminum rod by a medium frequency induction coil, and then hot extruding the aluminum rod into an aluminum rod by a horizontal extruder.

[0034] Preferably, the heating temperature of the aluminum rod is 420-440°C, for example, it can be 420°C, 422°C, 424°C, 426°C, 428°C, 430°C, 432°C, 434°C, 436°C, 438°C or 440°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the extrusion ratio of the hot extrusion is 5-10, for example, it can be 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 or 10, the extrusion temperature is 330-360°C, for example, it can be 330°C, 335°C, 340°C, 345°C, 350°C, 355°C or 360°C, and the extrusion speed is 4-7mm / s, for example, it can be 4mm / s, 4.5mm / s, 5mm / s, 5.5mm / s, 6mm / s, 6.5mm / s or 7mm / s, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0036] Preferably, the specifications of the aluminum rod are For example it could be or However, it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, recrystallization annealing is performed after the hot extrusion to further refine the grains, and the annealing temperature is 350-370°C, for example, it can be 350°C, 352°C, 354°C, 356°C, 358°C, 360°C, 362°C, 364°C, 366°C, 368°C or 370°C, and the annealing time is 2-4h, for example, it can be 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h or 4h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] Preferably, the hot drawing comprises: firstly heating the aluminum rod by a medium frequency induction coil, and then hot drawing the aluminum rod into an aluminum wire by a drawing machine.

[0039] Preferably, the heating temperature of the aluminum rod is 200-250°C, for example, it can be 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C or 250°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, the drawing speed of the hot drawing is 12-16 m / s, for example, it can be 12 m / s, 12.5 m / s, 13 m / s, 13.5 m / s, 14 m / s, 14.5 m / s, 15 m / s, 15.5 m / s or 16 m / s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] Preferably, the specification of the aluminum wire is For example it could be or However, it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] Preferably, stress relief annealing is performed after the hot drawing, and the annealing temperature is 220-250°C, for example, it can be 220°C, 225°C, 230°C, 235°C, 240°C, 245°C or 250°C, and the annealing time is 2-3h, for example, it can be 2h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3h, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0043] Preferably, the drawing speed of the cold drawing is 5-10 m / s, for example, it can be 5 m / s, 5.5 m / s, 6 m / s, 6.5 m / s, 7 m / s, 7.5 m / s, 8 m / s, 8.5 m / s, 9 m / s, 9.5 m / s or 10 m / s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] Preferably, the cryogenic treatment time is 10-14 h, for example, it can be 10 h, 10.5 h, 11 h, 11.5 h, 12 h, 12.5 h, 13 h, 13.5 h or 14 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] Preferably, the specification of the aluminum alloy wire is For example it could be or However, it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] In a second aspect, the present invention provides an aluminum alloy wire obtained by the preparation method according to the first aspect, wherein the aluminum alloy wire comprises the following components in terms of mass percentage:

[0047]

[0048] The balance is Al and inevitable impurity elements.

[0049] The mass percentage of Si is 0.3%-0.5%, for example, it can be 0.3%, 0.32%, 0.34%, 0.36%, 0.38%, 0.4%, 0.42%, 0.44%, 0.46%, 0.48% or 0.5%, the mass percentage of Fe is 0.1%-0.2%, for example, it can be 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19% or 0.2%, and the mass percentage of Mg is 0.15%-0.25%, for example, it can be 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, 0.24 % or 0.25%, the mass percentage of Zr is 0.1%-0.12%, for example, it can be 0.1%, 0.105%, 0.11%, 0.115% or 0.12%, the mass percentage of Cu is 0.1%-0.25%, for example, it can be 0.1%, 0.12%, 0.14%, 0.16%, 0.18%, 0.2%, 0.22%, 0.24% or 0.25%, the mass percentage of Cr is 0.1%-0.2%, for example, it can be 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19% or 0.2%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0050] In the present invention, the addition of Si element can promote the formation of heterogeneous crystal nuclei in the aluminum alloy, thereby playing a role in refining the grain structure.

[0051] In a third aspect, the present invention provides an application of the aluminum alloy wire as described in the second aspect, wherein the aluminum alloy wire is used in the fields of automobiles, electricity, electronics, machinery or construction.

[0052] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] The preparation method provided by the present invention achieves full refinement of aluminum alloy grains through rotary forging, hot extrusion and hot drawing, obtains fine-grained structure, and improves the structural uniformity and density of the material; the morphology and distribution of defects such as dislocations and stacking faults in the wire are regulated through cold drawing and deep cryogenic treatment, thereby improving the mechanical properties of the aluminum alloy wire; the synergistic cooperation between the above-mentioned treatment processes finally realizes the construction of multiple heterogeneous structures, and obtains aluminum alloy wires with excellent service performance, and the tensile strength of the obtained wire is ≥320MPa, the yield strength is ≥210MPa, the heat-resistant temperature is ≥240°C, and the conductivity is 50%IACS, achieving the effects of high strength, bending resistance, and high / low temperature resistance, which is conducive to large-scale promotion and application. DETAILED DESCRIPTION

[0055] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0056] Example 1

[0057] This embodiment provides an aluminum alloy wire and a preparation method thereof. The aluminum alloy wire comprises the following components in terms of mass percentage:

[0058]

[0059] The balance is Al and inevitable impurity elements.

[0060] In this embodiment, the preparation method comprises the following steps:

[0061] (1) Ingredients: According to the above-mentioned conductor components and mass percentages, pure aluminum ingots (purity ≥ 99.7wt%), aluminum-magnesium alloy, aluminum-silicon alloy, aluminum-copper alloy, aluminum-chromium alloy and aluminum-zirconium alloy are selected as raw materials;

[0062] (2) Melting: First, place the pure aluminum ingot in a regenerative gas-fired aluminum melting furnace and heat it until it melts, and control the melting temperature to 740°C. Then, transfer the aluminum liquid to a regenerative gas-fired insulation furnace with an electromagnetic stirring function, add various intermediate alloys, and use a circulation mode of forward rotation for 1 min and reverse rotation for 1 min to electromagnetically stir the aluminum alloy liquid for 8 min, so that the aluminum alloy liquid is fully stirred and evenly mixed. After all the aluminum is melted, use argon gas with a purity of 99.96% to spray a refining agent (sodium nitrate + graphite), and the amount of the refining agent is 0.14% of the total mass of the aluminum alloy liquid. After spraying for 25 minutes, degassing and impurity removal treatment is carried out, and after slagging, a covering agent is sprinkled on it and the mixture is allowed to stand for 30 minutes;

[0063] (3) Casting: Preheat the mold to 300°C, then cast the 700°C aluminum alloy liquid into the mold into a The aluminum billet is made into a round rod, and the cooling rate of the aluminum alloy liquid is controlled to be 60°C / s during casting. Then, the obtained aluminum billet is homogenized and annealed at a temperature of 485°C and a time of 8h.

[0064] (4) Rotary forging: The aluminum billet is first heated to 540°C in a resistance furnace, and then a rotary forging machine is used to rotary forge the aluminum billet into a specification of The aluminum rod is prepared by controlling the feeding speed to 6 mm / min and the rotation speed to 135 r / min, and then the obtained aluminum rod is subjected to stress relief annealing at a temperature of 285°C and an annealing time of 4 h;

[0065] (5) Hot extrusion: First, the aluminum rod is quickly heated to 430°C by a medium frequency induction coil, and then a horizontal extruder is used to hot extrude the aluminum rod into a specification of The aluminum rod is prepared by controlling the extrusion ratio to 8, the extrusion temperature to 345°C, and the extrusion speed to 6 mm / s. The obtained aluminum rod is then subjected to recrystallization annealing, and the annealing temperature is 360°C and the annealing time is 3h.

[0066] (6) Hot drawing: First, the aluminum rod is quickly heated to 230°C by a medium frequency induction coil, and then the aluminum rod is hot drawn into a specification of The aluminum wire is drawn at a speed of 14 m / s, and then the obtained aluminum wire is subjected to stress relief annealing at a temperature of 235°C and an annealing time of 2.5 h.

[0067] (7) Cold drawing: The aluminum wire is placed in a liquid nitrogen tank for rapid cooling, and then drawn at the liquid nitrogen temperature, with the drawing speed controlled at 8 m / s;

[0068] (8) Cryogenic treatment: The aluminum wire is placed in a liquid nitrogen tank for 12 hours of cryogenic treatment, and the final product is Aluminum alloy wire.

[0069] Example 2

[0070] This embodiment provides an aluminum alloy wire and a preparation method thereof. The aluminum alloy wire comprises the following components in terms of mass percentage:

[0071]

[0072]

[0073] The balance is Al and inevitable impurity elements.

[0074] In this embodiment, the preparation method comprises the following steps:

[0075] (1) Ingredients: According to the above-mentioned conductor components and mass percentages, pure aluminum ingots (purity ≥ 99.7wt%), aluminum-magnesium alloy, aluminum-silicon alloy, aluminum-copper alloy, aluminum-chromium alloy and aluminum-zirconium alloy are selected as raw materials;

[0076] (2) Melting: First, place the pure aluminum ingot in a regenerative gas-fired aluminum melting furnace and heat it until it melts, and control the melting temperature to 730°C. Then, transfer the aluminum liquid to a regenerative gas-fired insulation furnace with an electromagnetic stirring function, add various intermediate alloys, and use a circulation mode of forward rotation for 1 min and reverse rotation for 1 min to electromagnetically stir the aluminum alloy liquid for 8 min, so that the aluminum alloy liquid is fully stirred and evenly mixed. After all the aluminum alloy is melted, use argon gas with a purity of 99.96% to spray a refining agent (sodium nitrate + graphite), and the amount of the refining agent is 0.12% of the total mass of the aluminum alloy liquid. After spraying for 25 minutes, degassing and impurity removal treatment is carried out, and after slagging, a covering agent is sprinkled on it and the mixture is allowed to stand for 30 minutes;

[0077] (3) Casting: Preheat the mold to 250°C, then cast the 700°C aluminum alloy liquid into the mold into a The aluminum billet is cast into a round rod shape, and the cooling rate of the aluminum alloy liquid is controlled to be 30°C / s during casting. Then, the obtained aluminum billet is homogenized and annealed at a temperature of 470°C and a time of 12h.

[0078] (4) Rotary forging: The aluminum billet is first heated to 500°C in a resistance furnace, and then a rotary forging machine is used to rotary forge the aluminum billet into a specification of The aluminum rod is prepared by feeding at a speed of 2 mm / min and rotating at a speed of 30 r / min, and then the obtained aluminum rod is subjected to stress relief annealing at a temperature of 270°C and an annealing time of 5 h.

[0079] (5) Hot extrusion: First, the aluminum rod is quickly heated to 420°C by a medium frequency induction coil, and then a horizontal extruder is used to hot extrude the aluminum rod into a specification of The aluminum rod is prepared by controlling the extrusion ratio to 5, the extrusion temperature to 330°C, and the extrusion speed to 4 mm / s. The obtained aluminum rod is then subjected to recrystallization annealing, and the annealing temperature is 350°C and the annealing time is 4 h.

[0080] (6) Hot drawing: First, the aluminum rod is quickly heated to 200°C by a medium frequency induction coil, and then the aluminum rod is hot drawn into a specification of The aluminum wire is drawn at a speed of 12 m / s, and then the obtained aluminum wire is subjected to stress relief annealing at a temperature of 220°C and an annealing time of 3 h.

[0081] (7) Cold drawing: The aluminum wire is placed in a liquid nitrogen tank for rapid cooling, and then drawn at the liquid nitrogen temperature, with the drawing speed controlled at 5 m / s;

[0082] (8) Cryogenic treatment: The aluminum wire is placed in a liquid nitrogen tank for 10 hours of cryogenic treatment, and the final product is Aluminum alloy wire.

[0083] Example 3

[0084] This embodiment provides an aluminum alloy wire and a preparation method thereof. The aluminum alloy wire comprises the following components in terms of mass percentage:

[0085]

[0086] The balance is Al and inevitable impurity elements.

[0087] In this embodiment, the preparation method comprises the following steps:

[0088] (1) Ingredients: According to the above-mentioned conductor components and mass percentages, pure aluminum ingots (purity ≥ 99.7wt%), aluminum-magnesium alloy, aluminum-silicon alloy, aluminum-copper alloy, aluminum-chromium alloy and aluminum-zirconium alloy are selected as raw materials;

[0089] (2) Melting: First, place the pure aluminum ingot in a regenerative gas-fired aluminum melting furnace and heat it until it melts, and control the melting temperature to 750°C. Then, transfer the aluminum liquid to a regenerative gas-fired insulation furnace with an electromagnetic stirring function, add various intermediate alloys, and use a circulation mode of forward rotation for 1 min and reverse rotation for 1 min to electromagnetically stir the aluminum alloy liquid for 8 min, so that the aluminum alloy liquid is fully stirred and evenly mixed. After all the aluminum alloy is melted, use argon gas with a purity of 99.96% to spray a refining agent (sodium nitrate + graphite), and the amount of the refining agent is 0.15% of the total mass of the aluminum alloy liquid. After spraying for 25 minutes, degassing and impurity removal treatment is carried out, and after slagging, a covering agent is sprinkled on it and the mixture is left to stand for 30 minutes;

[0090] (3) Casting: Preheat the mold to 350°C, then cast the 710°C aluminum alloy liquid into the mold into a size of The aluminum billet is cast into a round rod shape, and the cooling rate of the aluminum alloy liquid is controlled to be 100°C / s during casting. Then, the obtained aluminum billet is homogenized and annealed at a temperature of 500°C and a time of 2h.

[0091] (4) Rotary forging: The aluminum billet is first heated to 580°C in a resistance furnace, and then a rotary forging machine is used to rotary forge the aluminum billet into a specification of The aluminum rod is prepared by feeding at a speed of 9 mm / min and rotating at a speed of 240 r / min, and then the obtained aluminum rod is subjected to stress relief annealing at a temperature of 300°C and an annealing time of 3 h.

[0092] (5) Hot extrusion: First, the aluminum rod is quickly heated to 440°C by a medium frequency induction coil, and then a horizontal extruder is used to hot extrude the aluminum rod into a specification of The aluminum rod is prepared by controlling the extrusion ratio to 10, the extrusion temperature to 360°C, and the extrusion speed to 7 mm / s. The obtained aluminum rod is then subjected to recrystallization annealing, and the annealing temperature is 370°C and the annealing time is 2 h.

[0093] (6) Hot drawing: First, the aluminum rod is quickly heated to 250°C by a medium frequency induction coil, and then the aluminum rod is hot drawn into a specification of The aluminum wire is drawn at a speed of 16 m / s, and then the obtained aluminum wire is subjected to stress relief annealing at a temperature of 250°C and an annealing time of 2 h.

[0094] (7) Cold drawing: The aluminum wire is placed in a liquid nitrogen tank for rapid cooling, and then drawn at the liquid nitrogen temperature, with the drawing speed controlled at 10 m / s;

[0095] (8) Cryogenic treatment: The aluminum wire is placed in a liquid nitrogen tank for 14 hours of cryogenic treatment, and the final specification is Aluminum alloy wire.

[0096] Example 4

[0097] This embodiment provides an aluminum alloy wire and a method for preparing the same. Except that aluminum-silicon alloy is not added in step (1), the remaining steps and conditions are the same as those in Example 1, and thus are not described in detail here.

[0098] Comparative Example 1

[0099] This comparative example provides an aluminum alloy wire and a preparation method thereof. Except for slowly heating the aluminum rod to 430° C. in a resistance furnace in step (5), the remaining steps and conditions are the same as those in Example 1, and thus are not described in detail here.

[0100] Comparative Example 2

[0101] This comparative example provides an aluminum alloy wire and a preparation method thereof. Except for slowly heating the aluminum rod to 230° C. in a resistance furnace in step (6), the remaining steps and conditions are the same as those in Example 1, and thus are not described in detail here.

[0102] Comparative Example 3

[0103] This comparative example provides an aluminum alloy wire and a method for preparing the same. Except for slowly cooling the aluminum wire in water and drawing the aluminum wire in water in step (7), the remaining steps and conditions are the same as those in Example 1 and are not described in detail here.

[0104] Comparative Example 4

[0105] This comparative example provides an aluminum alloy wire and a method for preparing the same. Except that the cryogenic treatment in step (8) is not performed, the remaining steps and conditions are the same as those in Example 1, and thus will not be described in detail herein.

[0106] Performance Testing

[0107] (1) According to the national standard GB / T228, the tensile strength and yield strength of the aluminum alloy wire were tested by room temperature tensile testing on an electronic tensile testing machine;

[0108] (2) With reference to the national standards GB / T2423 and GB / T11007, an infrared thermometer and a conductivity tester were used to test the temperature resistance and conductivity of aluminum alloy wires respectively.

[0109] After testing, the performance parameters of the aluminum alloy wires obtained in Examples 1-4 and Comparative Examples 1-4 are shown in Table 1 below.

[0110] Table 1

[0111]

[0112] It can be seen that the preparation method provided by the present invention achieves sufficient refinement of aluminum alloy grains through rotary forging, hot extrusion and hot drawing, obtains fine-grained structure, and improves the structural uniformity and density of the material; the morphology and distribution of defects such as dislocations and stacking faults in the wire are regulated by cold drawing and deep cryogenic treatment, thereby improving the mechanical properties of the aluminum alloy wire; the synergistic cooperation between the above-mentioned treatment processes finally realizes the construction of multiple heterogeneous structures, and obtains aluminum alloy wires with excellent service performance, and the tensile strength of the obtained wire is ≥320MPa, the yield strength is ≥210MPa, the heat resistance temperature is ≥240°C, and the conductivity is 50%IACS, achieving the effects of high strength, bending resistance, and high / low temperature resistance, which is conducive to large-scale promotion and application.

[0113] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an aluminum alloy wire, characterized in that: The preparation method comprises batching, smelting, casting, rotary forging, hot extrusion, hot drawing, cold drawing and cryogenic treatment in sequence; The materials used in the batching include pure aluminum ingots and master alloys, and the purity of the pure aluminum ingots is ≥99.7wt%; After the casting, rotary forging, hot extrusion and hot drawing, annealing treatment is performed independently respectively; The heating processes of hot extrusion and hot drawing are independently carried out in medium frequency induction coils; The cooling process of the cold drawing and the cryogenic treatment are carried out independently in a liquid nitrogen tank.

2. The preparation method according to claim 1, characterized in that: The master alloy includes any one of aluminum-magnesium alloy, aluminum-silicon alloy, aluminum-copper alloy, aluminum-chromium alloy or aluminum-zirconium alloy, or a combination of at least two thereof.

3. The preparation method according to claim 2, characterized in that: The smelting process comprises: firstly heating the pure aluminum ingot to melt, then adding the master alloy and stirring, after all the alloys are melted, using an inert gas to spray a refining agent into the obtained aluminum alloy liquid, continuing to stir, then standing and removing slag; The smelting is carried out in a regenerative gas-fired aluminum melting furnace, and the set temperature is 730-750°C; The inert gas includes helium and / or argon; The refining agent includes sodium nitrate and graphite.

4. The preparation method according to claim 3, characterized in that: The casting comprises: preheating the mold first, and then casting the aluminum alloy liquid into a round rod-shaped aluminum billet in the mold; The preheating temperature of the mold is 250-350°C; The casting temperature of the aluminum alloy liquid is 700-710°C, and the cooling rate is 30-100°C / s; The specifications of the round rod-shaped aluminum billet are After the casting, homogenization annealing is performed, and the annealing temperature is 470-500° C. and the annealing time is 2-12 hours.

5. The preparation method according to claim 4, characterized in that: The rotary forging comprises: firstly heating the aluminum billet, and then rotary forging the aluminum billet into an aluminum rod; The heating temperature of the aluminum billet is 500-580°C; The feed speed of the rotary forging is 2-9 mm / min, and the rotation speed is 30-240 r / min; The specifications of the aluminum rod are After the rotary forging, stress relief annealing is performed, and the annealing temperature is 270-300° C. and the annealing time is 3-5 hours.

6. The preparation method according to claim 5, characterized in that: The hot extrusion comprises: firstly heating the aluminum rod by a medium frequency induction coil, and then hot extruding the aluminum rod into an aluminum rod by a horizontal extruder; The heating temperature of the aluminum rod is 420-440°C; The extrusion ratio of the hot extrusion is 5-10, the extrusion temperature is 330-360°C, and the extrusion speed is 4-7mm / s; The specifications of the aluminum rod are After the hot extrusion, recrystallization annealing is performed, and the annealing temperature is 350-370° C. and the annealing time is 2-4 hours.

7. The preparation method according to claim 6, characterized in that: The hot drawing comprises: firstly heating the aluminum rod by a medium frequency induction coil, and then using a drawing machine to hot draw the aluminum rod into an aluminum wire; The heating temperature of the aluminum rod is 200-250°C; The hot drawing speed is 12-16 m / s; The specifications of the aluminum wire are After the hot drawing, stress relief annealing is performed, and the annealing temperature is 220-250° C. and the annealing time is 2-3 hours.

8. The preparation method according to claim 7, characterized in that: The cold drawing speed is 5-10 m / s; The cryogenic treatment time is 10-14h; The specifications of the aluminum alloy wire are 9. An aluminum alloy wire obtained by the preparation method according to any one of claims 1 to 8, characterized in that: In terms of mass percentage, the aluminum alloy wire Includes the following components: The balance is Al and inevitable impurity elements.

10. An application of the aluminum alloy wire as claimed in claim 9, characterized in that: The aluminum alloy wire is used in the fields of automobile, electricity, electronics, machinery or construction.

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