Ultrahigh-strength conductive aluminum alloy wire and preparation method thereof

Abstract

The invention provides an ultrahigh-strength conductive aluminum alloy wire and a preparation method thereof, and the ultrahigh-strength conductive aluminum alloy wire comprises the following components in percentage by mass: 0.5-0.8% of Mg; 0.6% to 0.9% of Si; 0.15% to 0.25% of Cu; less than or equal to 0.15% of Fe, less than or equal to 0.10% of other impurities and the balance of aluminum. According to the invention, after Cu is added into the existing alloy components, a coherent copper-containing precursor is formed in the second on-line solid solution process, and the copper-containing precursor has higher solubility resistance and can still be highly dispersed in a matrix after being drawn, so that the strength is greatly improved compared with that of a copper-base-free alloy.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials, and in particular to an ultra-high-strength conductive aluminum alloy wire and a preparation method thereof. Background Art

[0002] Aluminum alloy core aluminum stranded wire is a conductor that uses aluminum alloy wire as a reinforcing core and twisted hard aluminum wire on the outer layer. Compared with ordinary steel core aluminum stranded wire, the steel core is replaced by aluminum alloy, so the conductor is lighter and has higher conductivity, which can reduce the support load of line towers, reduce line losses, and improve transmission efficiency. At the same time, aluminum alloy can quickly form a dense oxide film in the atmospheric environment, and has better corrosion resistance than steel core. Therefore, this type of conductor has stronger adaptability in coastal, foggy, humid and other corrosive environments. However, the strength of the aluminum alloy core is lower than that of the steel core, resulting in its overall breaking force being lower than that of the steel core aluminum stranded wire of the same specification. Improving the strength of the existing aluminum alloy can significantly improve the breaking force of the aluminum alloy core aluminum stranded wire, making it more suitable for more application scenarios.

[0003] There are two technical paths for high-strength aluminum alloy wire in the existing technology. One is to draw the rod into wire after continuous casting and rolling, and then perform aging heat treatment on the wire. Its performance indicators are the current product performance standards: LHA1: tensile strength ≥315MPa, conductivity ≥52.5%IACS, elongation ≥3.5%; LHA2: tensile strength ≥295MPa, conductivity ≥53.0%IACS, elongation ≥3.5%. The second is to pre-age the rod after continuous casting and rolling, then draw it into wire, and then continue to age the wire. Its minimum tensile strength is between 315MPa and 340MPa, and its minimum conductivity is between 54%IACS and 56.5%.

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

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

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

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

[0008] In summary, based on existing standards and technical status, the strength and conductivity of aluminum alloys have been greatly improved, but the maximum strength is basically around 350MPa, and higher strength aluminum alloys are not involved. Summary of the invention

[0009] In view of the shortcomings of the prior art described above, the object of the present invention is to provide an ultra-high-strength conductive aluminum alloy wire and a preparation method thereof, so as to improve the breaking force of the aluminum alloy core aluminum stranded wire by improving the strength of the aluminum alloy wire, thereby solving the problem in the prior art that the strength of the aluminum alloy is not sufficient to significantly improve the breaking force of the aluminum alloy core aluminum stranded wire.

[0010] To achieve the above-mentioned purpose and other related purposes, the present 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.

[0011] Preferably, the following components are included 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.

[0012] Preferably, the following components are included 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.

[0013] Preferably, the following components are included 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.

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

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

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

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

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

[0019] S4: Casting the refined melt obtained in step S3 by continuous casting to obtain a cast billet;

[0020] S5: the ingot obtained in step S4 is subjected to a first online solid solution treatment and then enters a continuous rolling process to obtain an alloy rod;

[0021] S6: after the alloy rod obtained in step S5 is subjected to a second online solid solution treatment, it is subjected to online quenching, and then coiled;

[0022] S7: Continuously drawing the alloy rod material after being rolled in step S6 to a finished size wire;

[0023] S8: Aging treatment is performed on the finished size wire.

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

[0025] S2.1: First, melt the aluminum ingot in a smelting furnace at a melting temperature of 730°C to 750°C;

[0026] S2.2: The melt obtained in step S2.1 is transferred to a heat preservation furnace, and the melt temperature is adjusted to 720° C. to 740° C.; the raw materials prepared in step S1 are added to the melt for melting.

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

[0028] S3.1: adding a refining agent to the melt obtained in step S2 for refining, stirring the melt at the same time, and controlling the melt temperature at 730°C to 750°C;

[0029] S3.2: Degas the melt with inert gas and remove the scum on the surface of the melt;

[0030] S3.3: The melt enters the continuous casting process through the guide groove; when the melt passes through the guide groove, the melt is filtered and purified online.

[0031] Preferably, the casting temperature of the refined melt in step S4 is 690°C to 710°C, the casting speed is between 7m and 10m / min, and the casting area is 3200mm 2 .

[0032] Preferably, in step S8, the heating temperature for aging treatment of the finished size wire is 150° C. to 190° C., and the holding time is 6 to 12 hours.

[0033] As described above, the ultra-high strength conductive aluminum alloy wire and the preparation method thereof according to the present invention have the following beneficial effects:

[0034] The present invention forms a continuous copper-containing precursor in the second online solid solution process by adding Cu content to the existing alloy components. The copper-containing precursor has higher dissolution resistance and can still be highly dispersed in the matrix after drawing, thereby greatly improving the strength compared with the copper-free base alloy. DETAILED DESCRIPTION

[0035] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

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

[0037] The ultra-high-strength conductive aluminum alloy wire of the present invention forms a continuous copper-containing precursor during the processing of the alloy wire by adding Cu to the components. The copper-containing precursor has higher solubility resistance and can still be highly dispersed in the matrix after drawing, thereby greatly improving the strength relative to the copper-free alloy. In this way, the tensile strength of the copper-free alloy wire in the prior art is greatly improved. The tensile strength of the ultra-high-strength conductive aluminum alloy wire is ≥4000MPa, the conductivity is ≥51%IACS, and the elongation is ≥4.5%, which is much higher than the product performance standards in the prior art.

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

[0039] First embodiment and preparation method thereof:

[0040] The ultra-high strength conductive aluminum alloy wire disclosed in this embodiment includes 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 preparation method of the ultra-high strength conductive aluminum alloy wire disclosed in this embodiment comprises the following steps:

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

[0043] A2: Place the aluminum ingot into a smelting furnace for melting at a melting temperature of 730°C to 750°C.

[0044] A3: The melt is transferred to a holding furnace and the melt temperature is adjusted to 720° C. to 740° C. Aluminum-silicon master alloy, aluminum-copper master alloy and magnesium ingot are added 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, fully stir the melt in the holding furnace, and control the melt temperature at 730℃~750℃.

[0046] A5: Use inert gas to degas the melt, and then remove the scum on 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 groove, aluminum-boron master alloy is added to the melt, and foam ceramics are used for filtration and electromagnetic purification.

[0048] A7: The melt is cast by continuous casting, the casting temperature is 690℃~710℃, the casting speed is between 7m~10m / min, and the casting area is 3200mm 2 .

[0049] A8: The cast ingot is continuously rolled. Before continuous rolling, the ingot is subjected to medium frequency induction heating to a temperature of 480°C to 520°C to complete the first online solid solution treatment, and then enters the continuous rolling process.

[0050] A9: The ingot is rolled into a continuous rolling mill to obtain an aluminum alloy rod with a diameter of 9.5 mm. It is then immediately subjected to medium-frequency induction heating to a temperature of 420°C to 450°C to complete the second online solution treatment.

[0051] A10: The aluminum alloy rod obtained in step A9 is rolled up by an automatic rolling device, and is subjected to online water cooling and quenching before rolling up. The temperature of the rolled aluminum alloy rod is controlled to be below 50° C.

[0052] A11: The aluminum alloy rod material rolled in step A10 is continuously drawn to a wire material with a diameter of 2.80 mm.

[0053] A12: Perform aging treatment on the finished wire. The heating temperature is 180℃ and the holding time is 8h.

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

[0055] In this embodiment, Fe comes from the aluminum ingot, and the Fe in the aluminum ingot cannot be completely removed. If the Fe content in the aluminum ingot used 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 in the aluminum ingot. The aluminum-boron master alloy added in step A6 has a very small mass percentage of boron, and the boron eventually enters other impurities.

[0056] Second embodiment and preparation method thereof:

[0057] The ultra-high-strength conductive aluminum alloy wire disclosed in this embodiment includes 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 preparation method of the ultra-high strength conductive aluminum alloy wire disclosed in this embodiment comprises the following steps:

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

[0060] B2: Place the aluminum ingot into a smelting furnace for melting at a melting temperature of 730°C to 750°C.

[0061] B3: The melt is transferred to a holding furnace and the melt temperature is adjusted to 720° C. to 740° C. Aluminum-silicon master alloy, aluminum-copper master alloy and magnesium ingot are added according to the mass fraction requirements of each component of the ultra-high-strength conductive aluminum alloy wire in this embodiment.

[0062] B4: Use a refining agent to refine the melt in the holding furnace, and at the same time fully stir the melt in the holding furnace, and control the melt temperature at 730℃~750℃.

[0063] B5: Degas the melt with inert gas, and then remove the scum on 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 groove, aluminum-boron master alloy is added to the melt, and foam ceramics are used for filtration and electromagnetic purification.

[0065] B7: The melt is cast by continuous casting, the casting temperature is 690℃~710℃, the casting speed is between 7m~10m / min, and the casting area is 3200mm 2 .

[0066] B8: The cast ingot is continuously rolled. Before continuous rolling, the ingot is subjected to medium frequency induction heating to a temperature of 480°C to 520°C to complete the first online solid solution, and then enters the continuous rolling process.

[0067] B9: The ingot is rolled into a continuous rolling mill to obtain an aluminum alloy rod with a diameter of 9.5 mm. It is then immediately subjected to medium frequency induction heating to a temperature of 420°C to 450°C to complete the second online solution treatment.

[0068] B10: The aluminum alloy rod obtained in step B9 is rolled up by an automatic rolling device, and is subjected to online water cooling and quenching before rolling up. The temperature of the rolled aluminum alloy rod is controlled to be below 50° C.

[0069] B11: The aluminum alloy rod material rolled in step B10 is continuously drawn to a wire material with a diameter of 3.20 mm.

[0070] B12: Perform aging treatment on the finished wire. The heating temperature is 180℃ and the holding time is 8h.

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

[0072] In this embodiment, Fe comes from the aluminum ingot, and the Fe in the aluminum ingot cannot be completely removed. If the Fe content in the aluminum ingot used 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 in the aluminum ingot. The aluminum-boron master alloy added in step A6 has a very small mass percentage of boron, and the boron eventually enters other impurities.

[0073] The third embodiment and its preparation method:

[0074] The ultra-high-strength conductive aluminum alloy wire disclosed in this embodiment includes 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 preparation method of the ultra-high strength conductive aluminum alloy wire disclosed in this embodiment comprises the following steps:

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

[0077] C2: Place the aluminum ingot into a smelting furnace for melting at a melting temperature of 730°C to 750°C.

[0078] C3: The melt is transferred to a holding furnace and the melt temperature is adjusted to 720° C. to 740° C. Aluminum-silicon master alloy, aluminum-copper master alloy and magnesium ingot are added 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 with a refining agent, and the melt in the holding furnace is fully stirred, and the melt temperature is controlled at 730°C to 750°C.

[0080] C5: Degas the melt with inert gas, and then remove the scum on the surface of the melt;

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

[0082] C7: The melt is cast by continuous casting, the casting temperature is 690℃~710℃, the casting speed is between 7m~10m / min, and the casting area is 3200mm 2 .

[0083] C8: The cast ingot is continuously rolled. Before continuous rolling, the ingot is subjected to medium frequency induction heating to a temperature of 480°C to 520°C to complete the first online solid solution, and then enters the continuous rolling process.

[0084] C9: The ingot is rolled into a continuous rolling mill to obtain an aluminum alloy rod with a diameter of 9.5 mm. It is then immediately subjected to medium frequency induction heating to a temperature of 420°C to 450°C to complete the second online solution treatment.

[0085] C10: The aluminum alloy rod obtained in step C9 is rolled up by an automatic rolling device, and is subjected to online water cooling and quenching before rolling up, and the temperature of the rolled aluminum alloy rod is controlled to be below 50° C.

[0086] C11: The aluminum alloy rod material rolled in step C10 is continuously drawn to a wire material with a diameter of 3.60 mm.

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

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

[0089] In this embodiment, Fe comes from the aluminum ingot, and the Fe in the aluminum ingot cannot be completely removed. If the Fe content in the aluminum ingot used 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 in the aluminum ingot. The aluminum-boron master alloy added in step C6 has a very small mass percentage of boron, and the boron eventually enters other impurities.

[0090] The present invention relates to an ultra-high-strength conductive aluminum alloy wire and a preparation method thereof. By adding Cu to the components, a coherent copper-containing precursor is formed during the processing of the alloy wire. The copper-containing precursor has higher dissolution resistance and can solve the problem of low overall breaking force of aluminum alloy core aluminum stranded wire in the prior art. While meeting certain conductivity and tensile capacity, the breaking force of the aluminum alloy core aluminum stranded wire is greatly improved by improving the strength of the aluminum alloy, so that it can be used in more scenarios.

[0091] Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0092] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may 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 a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. An ultra-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%, and the rest is aluminum content.

2. The ultra-high strength conductive aluminum alloy wire according to claim 1, characterized in that: In terms of 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.

3. The ultra-high strength conductive aluminum alloy wire according to claim 1, characterized in that: In terms of 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 rest is aluminum content.

4. The ultra-high strength conductive aluminum alloy wire according to claim 1, characterized in that: In terms of 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.

5. The ultra-high strength conductive aluminum alloy wire according to claim 1, characterized in that: The tensile strength of the ultra-high-strength conductive aluminum alloy wire is ≥4000MPa, the conductivity is ≥51%IACS, and the elongation is ≥4.5%.

6. A method for preparing an ultra-high strength conductive aluminum alloy wire, characterized in that: The following steps are involved: S1: preparing raw materials according to the composition of the ultra-high strength conductive aluminum alloy wire according to any one of claims 1 to 5; S2: Melting the raw materials in step S1 in a melting furnace to obtain a melt; S3: refining the melt to obtain a refined melt; S4: Casting the refined melt obtained in step S3 by continuous casting to obtain a cast billet; S5: the ingot obtained in step S4 is subjected to a first online solid solution treatment and then enters a continuous rolling process to obtain an alloy rod; S6: after the alloy rod obtained in step S5 is subjected to second online solid solution treatment, it is subjected to online quenching and then coiled; S7: Continuously drawing the alloy rod material after being rolled in step S6 to a finished size wire material; S8: Aging treatment is performed on the finished size wire.

7. The method for preparing the ultra-high strength conductive aluminum alloy wire according to claim 6, characterized in that: Step S2 also includes the following steps: S2.1: First, melt the aluminum ingot in a smelting furnace at a melting temperature of 730°C to 750°C; S2.2: The melt obtained in step S2.1 is transferred to a heat preservation furnace, and the melt temperature is adjusted to 720° C. to 740° C.; the raw materials prepared in step S1 are added to the melt for melting.

8. The method for preparing the ultra-high strength conductive aluminum alloy wire according to claim 6, characterized in that: Step S3 also includes the following steps: S3.1: adding a refining agent to the melt obtained in step S2 for refining, stirring the melt at the same time, and controlling the melt temperature at 730°C to 750°C; S3.2: Degas the melt with inert gas and remove the scum on the surface of the melt; S3.3: The melt enters the continuous casting process through the guide groove; when the melt passes through the guide groove, the melt is filtered and purified online.

9. The method for preparing the ultra-high strength conductive aluminum alloy wire according to claim 6, characterized in that: The casting temperature of the refined melt in step S4 is 690°C to 710°C, the casting speed is between 7m and 10m / min, and the casting area is 3200mm 2 .

10. The method for preparing the ultra-high strength conductive aluminum alloy wire according to claim 6, characterized in that: In step S8, the heating temperature for aging treatment of the finished size wire is 150°C to 190°C, and the insulation time is 6 to 12 hours.