An ultrahigh-strength conductive aluminum alloy wire and a preparation method thereof

Abstract

The application provides an ultrahigh-strength conductive aluminum alloy wire and a preparation method thereof. According to the mass percentage, the ultrahigh-strength conductive aluminum alloy wire comprises the following components: Mg: 0.5% to 0.8%; Si: 0.6% to 0.9%; Cu: 0.15% to 0.25%; Fe: less than or equal to 0.15%; other impurities: less than or equal to 0.10%; and the rest is aluminum. In the application, the Cu content is added in the existing alloy components, and a continuous copper-containing precursor is formed in the second online solid solution process. The copper-containing precursor has higher anti-dissolution, and can be highly dispersed in the matrix after drawing, so that the strength is greatly improved compared with the copper-free base alloy.

Description

Technical Field

[0001] This invention relates to the field of metal materials technology, and in particular to an ultra-high strength conductive aluminum alloy wire and its preparation method. Background Technology

[0002] Aluminum alloy core stranded wire is a type of conductor that uses aluminum alloy wire as the reinforcing core and an outer layer of stranded hard aluminum wire. Compared to ordinary steel core stranded wire, because the steel core is replaced by aluminum alloy, the conductor is lighter and has higher conductivity, which can reduce the supporting load on line towers, reduce line losses, and improve transmission efficiency. At the same time, aluminum alloy can quickly form a dense oxide film in atmospheric environments, providing better corrosion resistance than steel cores. Therefore, this type of conductor has stronger adaptability to corrosive environments such as coastal areas, foggy areas, and humid areas. However, the strength of the aluminum alloy core is lower than that of the steel core, resulting in a lower overall tensile strength compared to steel core stranded wire of the same specifications. Increasing the strength of the existing aluminum alloy can significantly improve the tensile strength of aluminum alloy core stranded wire, making it more suitable for a wider range of applications.

[0003] There are two existing technical approaches for high-strength aluminum alloy wire. The first approach involves continuously casting and rolling a rod, then drawing it into wire, followed by aging heat treatment. The performance indicators are as follows according to current product performance standards: LHA1: tensile strength ≥ 315 MPa, conductivity ≥ 52.5% IACS, elongation ≥ 3.5%; LHA2: tensile strength ≥ 295 MPa, conductivity ≥ 53.0% IACS, elongation ≥ 3.5%. The second approach involves continuously casting and rolling a rod, then pre-aging it before drawing it into wire, followed by aging treatment. The minimum tensile strength in this approach is between 315 MPa and 340 MPa, and the minimum conductivity is between 54% IACS and 56.5%.

[0004] The performance indicators given in the existing patent document with patent number CN109295352B are: tensile strength ≥350MPa, conductivity ≥48.0%IACS.

[0005] The performance indicators given in the document with patent number CN111069311B are: tensile strength ≥341MPa, conductivity ≥54.7%IACS.

[0006] The performance indicators given in the document with patent number CN115595459B are: tensile strength ≥340MPa, conductivity ≥55.0%IACS, and elongation ≥5%.

[0007] The performance indicators given in the document with patent number CN111270112A are: tensile strength ≥315MPa, conductivity ≥56.5%IACS.

[0008] In summary, based on existing standards and current technology, the strength and conductivity of aluminum alloys have been significantly improved, but the highest strength is generally around 350 MPa, and there is no mention of aluminum alloys with higher strength. Summary of the Invention

[0009] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an ultra-high strength conductive aluminum alloy wire and its preparation method, which improves the tensile strength of aluminum alloy core stranded wire by increasing the strength of the aluminum alloy wire, thereby solving the problem that the strength of aluminum alloy is insufficient to significantly improve the tensile strength of aluminum alloy core stranded wire in the prior art.

[0010] To achieve the above and other related objectives, the present invention provides an ultra-high strength conductive aluminum alloy wire, comprising the following components by mass percentage: Mg: 0.5% to 0.8%; Si: 0.6% to 0.9%; Cu: 0.15% to 0.25%; Fe: ≤0.15%; other impurities ≤0.10%; and the remainder being aluminum content.

[0011] Preferably, by mass percentage, it includes the following components: Mg: 0.5% to 0.6%; Si: 0.6% to 0.7%; Cu: 0.15% to 0.20%; Fe: ≤0.15%; other impurities ≤0.10%; and the remainder is aluminum content.

[0012] Preferably, by mass percentage, it includes the following components: Mg: 0.6% to 0.7%; Si: 0.7% to 0.8%; Cu: 0.15% to 0.20%; Fe: ≤0.15%; other impurities ≤0.10%; and the remainder is aluminum content.

[0013] Preferably, by mass percentage, it includes the following components: Mg: 0.7% to 0.8%; Si: 0.7% to 0.9%; Cu: 0.15% to 0.20%; Fe: ≤0.15%; other impurities ≤0.10%; and the remainder is aluminum content.

[0014] Preferably, the ultra-high strength conductive aluminum alloy wire has a tensile strength ≥4000MPa, conductivity ≥51%IACS, and elongation ≥4.5%.

[0015] To achieve the above or other objectives, the present invention also discloses a method for preparing an ultra-high strength conductive aluminum alloy wire, comprising the following steps:

[0016] S1: Prepare raw materials according to the composition of the ultra-high strength conductive aluminum alloy wire mentioned above;

[0017] S2: Melt the raw materials from step S1 in a melting furnace to obtain a melt;

[0018] S3: Refine the melt to obtain a refined melt;

[0019] S4: Cast the refined melt obtained in step S3 using continuous casting to obtain a billet;

[0020] S5: After the billet obtained in step S4 is first solution-treated online, it is rolled in the continuous rolling process to obtain alloy rods;

[0021] S6: After the alloy rod obtained in step S5 is subjected to a second online solution treatment, it is then quenched online and then coiled up.

[0022] S7: Continuously draw the alloy rod after winding in step S6 to the finished wire size;

[0023] S8: Perform aging treatment on finished wires of various sizes.

[0024] Preferably, step S2 further includes the following steps:

[0025] S2.1: First, melt the aluminum ingots in a smelting furnace at a melting temperature of 730℃~750℃;

[0026] S2.2: Transfer the melt obtained in step S2.1 to a holding furnace and adjust the melt temperature to 720℃~740℃; add the raw materials prepared in step S1 into the melt for melting.

[0027] Preferably, step S3 further includes the following steps:

[0028] S3.1: Add refining agent to the melt obtained in step S2 for refining, while stirring the melt and controlling the melt temperature at 730℃~750℃.

[0029] S3.2: Use inert gas to degas the melt and remove the slag from the surface of the melt;

[0030] S3.3: The melt enters the continuous casting process through the guide channel; the melt is filtered and purified online as it passes through the guide channel.

[0031] Preferably, in step S4, the casting temperature of the refined melt is 690℃~710℃, the casting speed is between 7m~10m / min, and the billet area is 3200mm². 2 .

[0032] Preferably, in step S8, the heating temperature for aging treatment of the finished wire is 150℃~190℃, and the holding time is 6~12h.

[0033] As described above, the ultra-high strength conductive aluminum alloy wire and its preparation method disclosed in this invention have the following beneficial effects:

[0034] This invention forms a coherent copper-containing precursor during the second online solid solution process by adding Cu to the existing alloy composition. The copper-containing precursor has higher resistance to dissolution and can still be highly dispersed in the matrix after drawing, thereby significantly improving the strength compared to copper-free alloys. Detailed Implementation

[0035] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0036] This invention provides an ultra-high strength conductive aluminum alloy wire, which comprises the following components by mass percentage: Mg: 0.5% to 0.8%; Si: 0.6% to 0.9%; Cu: 0.15% to 0.25%; Fe: ≤0.15%; other impurities ≤0.10%; and the remainder is aluminum content.

[0037] The ultra-high strength conductive aluminum alloy wire of this invention, by adding Cu to the composition, forms a coherent copper-containing precursor during the alloy wire processing. This copper-containing precursor has higher resistance to dissolution and remains highly dispersed in the matrix after drawing, thus significantly increasing the strength compared to copper-free alloys. This represents a substantial improvement in tensile strength compared to existing copper-free alloy wires. The ultra-high strength conductive aluminum alloy wire has a tensile strength ≥4000MPa, conductivity ≥51% IACS, and elongation ≥4.5%, far exceeding the performance standards of existing products.

[0038] This invention discloses three ultra-high strength conductive aluminum alloy wires with different component contents and their preparation methods through three embodiments. The three embodiments and their preparation methods are as follows:

[0039] First embodiment and its preparation method:

[0040] The ultra-high strength conductive aluminum alloy wire disclosed in this embodiment comprises the following components by mass percentage: Mg: 0.5% to 0.6%; Si: 0.6% to 0.7%; Cu: 0.15% to 0.20%; Fe: ≤0.15%; other impurities ≤0.10%; and the remainder is aluminum content.

[0041] The method for preparing the ultra-high strength conductive aluminum alloy wire disclosed in this embodiment includes the following steps:

[0042] A1: Based on the above composition of ultra-high strength conductive aluminum alloy wire, prepare the raw materials; the raw materials include aluminum ingots, aluminum-silicon master alloy, aluminum-copper master alloy, and magnesium ingots; the aluminum-silicon master alloy is Al-Si20 alloy (Si content is 20% by mass), and the aluminum-copper master alloy is Al-Cu20 alloy (Cu content is 20% by mass dispersion).

[0043] A2: Place the aluminum ingots into a smelting furnace for melting at a temperature of 730℃~750℃.

[0044] A3: Transfer the melt to a holding furnace and adjust the melt temperature to 720℃~740℃. Add aluminum-silicon master alloy, aluminum-copper master alloy, and magnesium ingot according to the mass fraction requirements of each component of the ultra-high strength conductive aluminum alloy wire in this embodiment.

[0045] A4: Use a refining agent to refine the melt in the holding furnace, while simultaneously stirring the melt in the holding furnace and controlling the melt temperature at 730℃~750℃.

[0046] A5: Use inert gas to degas the melt, and then remove the slag from the surface of the melt;

[0047] A6: The melt is transferred from the holding furnace to the continuous casting process. When the melt passes through the guide trough, an aluminum-boron master alloy is added to the melt, and foam ceramics are used for filtration and electromagnetic purification.

[0048] A7: The molten metal is cast using continuous casting at a temperature of 690℃~710℃ and a casting speed of 7m~10m / min. The billet area is 3200mm². 2 .

[0049] A8: The cast billet is continuously rolled. Before continuous rolling, the billet is heated by medium frequency induction heating to reach a temperature of 480℃~520℃ to complete the first online solution treatment, and then enters the continuous rolling process.

[0050] A9: The billet enters the continuous rolling mill for rolling to obtain an aluminum alloy rod with a diameter of 9.5mm. Then, it is immediately subjected to medium-frequency induction heating to reach a temperature of 420℃~450℃ to complete the second online solution treatment.

[0051] A10: The aluminum alloy rod obtained in step A9 is wound up using an automatic winding device, and online water quenching is performed before winding. The temperature of the aluminum alloy rod after winding is controlled below 50℃.

[0052] A11: Continuously draw the aluminum alloy rod coiled in step A10 into a wire with a diameter of 2.80mm.

[0053] A12: Aging treatment is performed on the finished wire. The heating temperature is 180℃, and the holding time is 8 hours.

[0054] The final product performance indicators in this embodiment are: tensile strength of 410MPa, conductivity of 51.5% IACS, and elongation ≥4.8%.

[0055] In this embodiment, the Fe originates from the aluminum ingot. Since Fe cannot be completely removed from the aluminum ingot, if the Fe content in the used aluminum ingot exceeds the mass percentage of Fe in the ultra-high strength conductive aluminum alloy wire, the aluminum ingot needs to be processed and purified to reduce the mass percentage of Fe. The aluminum-boron master alloy added in step A6, due to its very low boron mass percentage, ultimately results in the boron entering other impurities.

[0056] Second embodiment and its preparation method:

[0057] The ultra-high strength conductive aluminum alloy wire disclosed in this embodiment comprises the following components by mass percentage: Mg: 0.6% to 0.7%; Si: 0.7% to 0.8%; Cu: 0.15% to 0.20%; Fe: ≤0.15%; other impurities ≤0.10%; and the remainder is aluminum content.

[0058] The method for preparing the ultra-high strength conductive aluminum alloy wire disclosed in this embodiment includes the following steps:

[0059] B1: Based on the above composition of ultra-high strength conductive aluminum alloy wire, prepare raw materials; the raw materials include aluminum ingots, aluminum-silicon master alloy, aluminum-copper master alloy, and magnesium ingots; the aluminum-silicon master alloy is Al-Si20 alloy (Si content is 20% by mass), and the aluminum-copper master alloy is Al-Cu20 alloy (Cu content is 20% by mass dispersion).

[0060] B2: Place the aluminum ingots into a smelting furnace for melting at a temperature of 730℃~750℃.

[0061] B3: Transfer the melt to a holding furnace and adjust the melt temperature to 720℃~740℃. Add aluminum-silicon master alloy, aluminum-copper master alloy, and magnesium ingot according to the mass fraction requirements of each component of the ultra-high strength conductive aluminum alloy wire in this embodiment.

[0062] B4: The melt in the holding furnace is refined using a refining agent, and the melt in the holding furnace is thoroughly stirred while the melt temperature is controlled at 730℃~750℃.

[0063] B5: Use inert gas to degas the melt, and then remove the slag from the surface of the melt;

[0064] B6: The melt is transferred from the holding furnace to the continuous casting process. When the melt passes through the guide channel, an aluminum-boron master alloy is added to the melt, and foam ceramics are used for filtration and electromagnetic purification.

[0065] B7: The molten metal is cast using continuous casting at a temperature of 690℃~710℃ and a casting speed of 7m~10m / min. The billet area is 3200mm². 2 .

[0066] B8: The cast billet is continuously rolled. Before continuous rolling, the billet is heated by medium frequency induction heating to reach a temperature of 480℃~520℃ to complete the first online solution treatment, and then enters the continuous rolling process.

[0067] B9: The billet enters the continuous rolling mill for rolling to obtain an aluminum alloy rod with a diameter of 9.5mm. Then, it is immediately subjected to medium-frequency induction heating to reach a temperature of 420℃~450℃ to complete the second online solution treatment.

[0068] B10: The aluminum alloy rod obtained in step B9 is wound up using an automatic winding device, and online water quenching is performed before winding. The temperature of the aluminum alloy rod after winding is controlled below 50°C.

[0069] B11: Continuously draw the aluminum alloy rod coiled in step B10 into a wire with a diameter of 3.20mm.

[0070] B12: Aging treatment is performed on the finished wire. The heating temperature is 180℃, and the holding time is 8 hours.

[0071] The final product performance indicators in this embodiment are: tensile strength of 415MPa, conductivity of 51.8% IACS, and elongation ≥4.9%.

[0072] In this embodiment, the Fe originates from the aluminum ingot. Since Fe cannot be completely removed from the aluminum ingot, if the Fe content in the used aluminum ingot exceeds the mass percentage of Fe in the ultra-high strength conductive aluminum alloy wire, the aluminum ingot needs to be processed and purified to reduce the mass percentage of Fe. The aluminum-boron master alloy added in step A6, due to its very low boron mass percentage, ultimately results in the boron entering other impurities.

[0073] Third embodiment and its preparation method:

[0074] The ultra-high strength conductive aluminum alloy wire disclosed in this embodiment comprises the following components by mass percentage: Mg: 0.7% to 0.8%; Si: 0.7% to 0.9%; Cu: 0.15% to 0.20%; Fe: ≤0.15%; other impurities ≤0.10%; and the remainder is aluminum content.

[0075] The method for preparing the ultra-high strength conductive aluminum alloy wire disclosed in this embodiment includes the following steps:

[0076] C1: Based on the above composition of ultra-high strength conductive aluminum alloy wire, prepare raw materials; the raw materials include aluminum ingots, aluminum-silicon master alloy, aluminum-copper master alloy, and magnesium ingots; the aluminum-silicon master alloy is Al-Si20 alloy (Si content is 20% by mass), and the aluminum-copper master alloy is Al-Cu20 alloy (Cu content is 20% by mass dispersion).

[0077] C2: The aluminum ingots are placed in a smelting furnace for melting at a temperature of 730℃~750℃.

[0078] C3: Transfer the melt to a holding furnace and adjust the melt temperature to 720℃~740℃. Add aluminum-silicon master alloy, aluminum-copper master alloy, and magnesium ingot according to the mass fraction requirements of each component of the ultra-high strength conductive aluminum alloy wire in this embodiment.

[0079] C4: The melt in the holding furnace is refined using a refining agent, while the melt in the holding furnace is thoroughly stirred and the melt temperature is controlled at 730℃~750℃.

[0080] C5: The melt is degassed with inert gas, and then the slag on the surface of the melt is removed;

[0081] C6: The melt is transferred from the holding furnace to the continuous casting process. When the melt passes through the guide channel, an aluminum-boron master alloy is added to the melt, and foam ceramics are used for filtration and electromagnetic purification.

[0082] C7: The molten metal is cast using continuous casting at a temperature of 690℃~710℃ and a casting speed of 7m~10m / min. The billet area is 3200mm². 2 .

[0083] C8: The cast billet is continuously rolled. Before continuous rolling, the billet is heated by medium frequency induction heating to reach a temperature of 480℃~520℃ to complete the first online solution treatment, and then enters the continuous rolling process.

[0084] C9: The billet enters the continuous rolling mill for rolling to obtain an aluminum alloy rod with a diameter of 9.5mm. Then, it is immediately subjected to medium-frequency induction heating to reach a temperature of 420℃~450℃ to complete the second online solution treatment.

[0085] C10: The aluminum alloy rod obtained in step C9 is wound up using an automatic winding device, and online water quenching is performed before winding. The temperature of the aluminum alloy rod after winding is controlled below 50°C.

[0086] C11: Continuously draw the aluminum alloy rod coiled in step C10 into a wire with a diameter of 3.60 mm.

[0087] C12: Aging treatment for finished wire. Heating temperature is 185℃, and holding time is 6 hours.

[0088] The final product performance indicators in this embodiment are: tensile strength of 420MPa, conductivity of 52.0% IACS, and elongation ≥4.5%.

[0089] In this embodiment, the Fe originates from the aluminum ingot. Since Fe cannot be completely removed from the aluminum ingot, if the Fe content in the used aluminum ingot exceeds the mass percentage of Fe in the ultra-high strength conductive aluminum alloy wire, the aluminum ingot needs to be processed and purified to reduce the mass percentage of Fe. The aluminum-boron master alloy added in step C6, due to its very low boron mass percentage, ultimately results in the boron entering other impurities.

[0090] The present invention relates to an ultra-high strength conductive aluminum alloy wire and its preparation method. By adding Cu to the components, a continuous copper-containing precursor is formed during the processing of the alloy wire. The copper-containing precursor has higher resistance to dissolution, which can solve the problem of low overall tensile strength of aluminum alloy core aluminum stranded wire in the prior art. While meeting certain conductivity and tensile strength requirements, the tensile strength of aluminum alloy core aluminum stranded wire is significantly improved by increasing the strength of aluminum alloy, making it applicable to more scenarios.

[0091] Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0092] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A high-strength conductive aluminum alloy wire, characterized in that: By mass percentage, it includes the following components: Mg: 0.5%–0.8%; Si: 0.6%–0.9%; Cu: 0.15%–0.25%; Fe: ≤0.15%, other impurities ≤0.10%, the remainder is aluminum content; The method for preparing the ultra-high strength conductive aluminum alloy wire includes the following steps: S1: Prepare raw materials according to the composition of the ultra-high strength conductive aluminum alloy wire; wherein the raw materials include aluminum-boron master alloy, and since the mass percentage of boron is very small, the boron will eventually enter other impurities; S2: Melt the raw materials from step S1 in a melting furnace to obtain a melt; S2.1: First, melt the aluminum ingots in a smelting furnace at a melting temperature of 730℃~750℃; S2.2: Transfer the melt obtained in step S2.1 to a holding furnace and adjust the melt temperature to 720℃~740℃; add the raw materials prepared in step S1 into the melt for melting. S3: Refine the melt to obtain a refined melt; S3.1: Add refining agent to the melt obtained in step S2 for refining, while stirring the melt and controlling the melt temperature at 730℃~750℃. S3.2: Use inert gas to degas the melt and remove the slag from the surface of the melt; S3.3: The melt enters the continuous casting process through the guide channel; the melt is filtered and purified online as it passes through the guide channel; S4: The refined melt obtained in step S3 is cast using continuous casting to obtain a billet; wherein the casting temperature of the refined melt is 690℃~710℃, the casting speed is 7m~10m / min, and the billet area is 3200mm². 2 ; S5: After the billet obtained in step S4 is first solution-treated online, it is rolled in the continuous rolling process to obtain alloy rods; S6: After the alloy rod obtained in step S5 is subjected to a second online solution treatment, it is then quenched online and then coiled up. S7: Continuously draw the alloy rod after winding in step S6 to the finished wire size; S8: Aging treatment is performed on finished wire rods of various sizes; the heating temperature for aging treatment of finished wire rods of various sizes is 150℃~190℃, and the holding time is 6~12h.

2. The ultra-high strength conductive aluminum alloy wire according to claim 1, characterized in that: By mass percentage, it includes the following components: Mg: 0.5%–0.6%; Si: 0.6%–0.7%; Cu: 0.15%–0.20%; Fe: ≤0.15%, other impurities ≤0.10%, and the remainder is aluminum content.

3. The ultra-high strength conductive aluminum alloy wire according to claim 1, characterized in that: By mass percentage, it includes the following components: Mg: 0.6%–0.7%; Si: 0.7%–0.8%; Cu: 0.15%–0.20%; Fe: ≤0.15%; other impurities ≤0.10%; and the remainder is aluminum content.

4. The ultra-high strength conductive aluminum alloy wire according to claim 1, characterized in that: By mass percentage, it includes the following components: Mg: 0.7%–0.8%; Si: 0.7%–0.9%; Cu: 0.15%–0.20%; Fe: ≤0.15%; other impurities ≤0.10%; and the remainder is aluminum content.

5. The ultra-high strength conductive aluminum alloy wire according to claim 1, characterized in that: The ultra-high strength conductive aluminum alloy wire has a tensile strength ≥400MPa, conductivity ≥51%IACS, and elongation ≥4.5%.