An age-hardenable aluminum alloy conductor material and its preparation method

Abstract

The present invention discloses an age-hardenable aluminum alloy conductor material and a preparation method thereof. The aluminum alloy comprises the following components in mass percentage: Mg: 0.50 - 0.90 wt.%, Si: 0.40 - 0.80 wt.%, Cu: 0.03 - 0.15 wt.%, La / Ce rare earth: 0.10 - 0.30 wt.%, and the balance is aluminum and inevitable impurity elements; the preparation method includes boronizing the aluminum melt, adding master alloys, melting and refining, in-furnace component analysis, component adjustment, casting and hot deformation, online solution and direct cooling quenching, pre-aging, drawing, and artificial aging. The preparation process of the present invention has a wide process window and good stability. The prepared single wire has a strength > 310 MPa, an elongation rate ≥ 6.3%, and a conductivity > 56.1% IACS, meeting the power transmission requirements of various service scenarios and having a significant energy-saving effect.

Description

Technical Field

[0001] The present invention relates to an age - hardenable aluminum alloy conductor material and a preparation method thereof, belonging to the technical field of electrical engineering materials. Technical Background

[0002] With the continuous development of China's economy, the rational development and utilization of electric energy have received increasing attention. At present, China's electric power load is mainly concentrated in the east, while electric power resources are mainly concentrated in the west, showing an overall reverse distribution characteristic. Therefore, the efficient and reliable transportation of electric power resources is of extremely important significance for China to promote regional coordinated development and build a resource - saving society. At present, the transportation of electric power resources is mainly achieved through overhead transmission lines. As an important part of overhead transmission lines, the performance of overhead conductors directly affects the efficiency and economy of electric power transportation. To meet the needs of China's power grid construction and improve the transportation capacity of overhead lines, it is urgent to develop new aluminum conductor materials suitable for long - distance, large - span, and large - capacity transmission lines.

[0003] At present, most overhead transmission lines still use traditional steel - cored aluminum stranded wires, which have disadvantages such as low current - carrying capacity, poor corrosion resistance, poor sag characteristics, and high construction difficulty, and are difficult to meet the requirements of long - distance power transmission. Compared with steel - cored aluminum stranded wires, age - hardenable all - aluminum alloy stranded wires have advantages such as high current - carrying capacity, large tension - weight ratio, good sag characteristics, corrosion resistance, simple connecting fittings, and low construction difficulty. Moreover, all - aluminum alloy stranded wires have no steel core, avoiding the generation of hysteresis loss and eddy - current loss during power transmission, with less power loss and significant energy - saving effect. Therefore, age - hardenable aluminum alloy conductor materials have received extensive attention.

[0004] Through continuous casting and rolling combined with drawing and single - stage artificial aging, the strength of the age - hardenable aluminum alloy conductor material prepared by traditional processes can reach 295 - 340 MPa, and the elongation after fracture is not less than 3%, but the conductivity is only 52.5 - 54.0% IACS. Patent CN111270112A discloses a high - strength and high - conductivity aluminum alloy for overhead conductors and a preparation method thereof. The strength of the overhead conductor reaches 315 MPa, and the conductivity reaches 56.5% IACS. However, when preparing the conductor, the round aluminum rod used is preferentially artificially aged, reducing the plasticity of the alloy and significantly increasing the deformation resistance of the alloy, making the single - wire drawing difficult and increasing the risk of wire breakage. Patent CN108588515A discloses a high - strength and high - conductivity aluminum alloy wire and a preparation method thereof. Through ultrasonic treatment combined with a two - stage aging process, a wire single - strand with a strength of 330 MPa and a conductivity of 54% IACS is prepared. Although this kind of wire has high strength, its conductivity is low and the line loss is large. Therefore, how to further improve the conductivity of age - hardenable aluminum alloy conductor materials on the premise of ensuring processing performance and strength is a technical problem that needs to be urgently solved. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the present invention provides a kind of age - hardenable aluminum alloy conductor material with large process tolerance and excellent comprehensive performance and its preparation method. By optimizing the alloy composition and improving the preparation process, the strength and conductivity are synergistically improved, so that the age - hardenable aluminum alloy conductor material can meet the power transmission requirements of various service scenarios.

[0006] One of the purposes of the present invention is to provide an age - hardenable aluminum alloy conductor material, and the aluminum alloy includes the following components by mass percentage:

[0007] Mg: 0.50 - 0.90 wt.%;

[0008] Si: 0.40 - 0.80 wt.%;

[0009] Cu: 0.03 - 0.15 wt.%;

[0010] Mixed rare earths of La and Ce: 0.10 - 0.30 wt.%;

[0011] The balance is Al and inevitable impurity elements;

[0012] Preferably, for the age - hardenable aluminum alloy conductor material, the aluminum alloy includes the following components by mass percentage:

[0013] Mg: 0.55 - 0.90 wt.%;

[0014] Si: 0.40 - 0.75 wt.%;

[0015] Cu: 0.03 - 0.10 wt.%;

[0016] Mixed rare earths of La and Ce: 0.15 - 0.25 wt.%;

[0017] The balance is Al and inevitable impurity elements;

[0018] Among them, the residual amount of B element in the inevitable impurity elements is less than 0.005 wt.%, the content of Fe element is less than 0.1 wt.%, and the total content of Ti, V, Cr, and Mn is less than 0.010 wt.%;

[0019] In the present invention, Mg and Si are the main alloying elements, which can form strengthening phases through natural aging and / or artificial aging to improve the strength and conductivity of aluminum alloys. In order to fully exert the beneficial effects of Mg and Si elements, in the present invention, the content of Mg is 0.50 - 0.90 wt.%, the content of Si is 0.40 - 0.80 wt.%, and the mass ratio of Mg to Si is 0.9 - 1.8, preferably 1.1 - 1.5. Specifically, such as 1.1, 1.2, 1.3, 1.4, 1.5.

[0020] In the material system designed in the present invention, when the contents of Mg and Si are lower than the lower limit of the composition range, the strength of the alloy decreases significantly. When they are higher than the upper limit of the composition range, the conductivity of the alloy decreases significantly. Further, when the mass ratio of Mg to Si is less than the lower limit of the mass ratio range, Si will be in excess. When the mass ratio of Mg to Si is greater than the upper limit of the mass ratio range, Mg will be in excess, both of which will significantly reduce the conductivity of the alloy and cannot fully exert the synergistic effect of Mg and Si elements.

[0021] In the present invention, adding Cu can inhibit the natural aging behavior of the aluminum alloy conductor material, while promoting the precipitation of strengthening phases and participating in the formation of strengthening phases to improve strength and elongation. In the present invention, the content of Cu is 0.03 - 0.15 wt.%, preferably 0.03 - 0.10 wt.%. Specifically, such as 0.03 wt.%, 0.04 wt.%, 0.05 wt.%, 0.06 wt.%, 0.07 wt.%, 0.08 wt.%, 0.09 wt.%, 0.10 wt.%. When the content of Cu is lower than 0.03 wt.%, the beneficial effects cannot be achieved. When the content of Cu is higher than 0.15 wt.%, the electrical conductivity will deteriorate, and the elongation of the alloy and the subsequent cold working performance will be reduced.

[0022] In the present invention, the composite addition of La and Ce elements can react with hydrogen in the aluminum melt to form LaH2 and / or CeH2 compounds, which are removed in the form of slag, reducing the slag inclusion and porosity shrinkage defects of the aluminum alloy conductor material. At the same time, it can modify the FeSi-rich impurity phase and primary Mg2Si phase in aluminum, improving the electrical conductivity and mechanical properties. In the present invention, the content of the La and Ce mixed rare earths is 0.10 - 0.30 wt.%, preferably 0.15 - 0.25 wt.%. Specifically, for example, 0.15 wt.%, 0.16 wt.%, 0.17 wt.%, 0.18 wt.%, 0.19 wt.%, 0.20 wt.%, 0.21 wt.%, 0.22 wt.%, 0.23 wt.%, 0.24 wt.%, 0.25 wt.%. When the content of La and Ce is lower than 0.10 wt.%, the purification effect of La and Ce on the melt and the modification effect on the primary phase cannot be fully exerted; when the content of La and Ce is higher than 0.30 wt.%, the excess La and Ce will form CeSi and / or LaSi compounds with Si in aluminum, reducing the strength and conductivity of the aluminum alloy conductor material. Further, when the content of La and Ce exceeds the composition range designed in the present invention, it is not conducive to the synergistic effect of the added elements. As a further preferred scheme, in the La and Ce mixed rare earths, the mass ratio of La to Ce is 35:65.

[0023] In the present invention, the B element is introduced by the aluminum raw material and boronization treatment, and it is necessary to control the residual amount of the B element to be lower than 0.005 wt.%. Under the composition system of the present invention, when the B content in the aluminum liquid is greater than 0.005 wt.%, the excessive B will be solid-solved in the aluminum matrix, reducing the conductivity of the material, and will react with the added rare earth elements, causing the consumption of rare earth elements and weakening the beneficial effects of rare earth elements.

[0024] In the present invention, the content of the impurity element Fe is less than 0.10 wt.%. Under the composition system of the present invention, when the Fe content is greater than or equal to 0.10 wt.%, it will react with Si to form a large number of continuously distributed coarse β-AlFeSi phases at the grain boundaries. The β-AlFeSi phase is a hard and brittle phase, which will cut the matrix and easily become a crack source, deteriorating the mechanical properties and processing properties of the aluminum alloy; at the same time, the formation of the β-AlFeSi phase will consume the Si element, reducing the volume fraction of the strengthening phase in the aluminum alloy, thereby reducing the mechanical properties of the aluminum alloy.

[0025] In the present invention, industrial-grade remelted aluminum ingots or primary aluminum liquid are used as raw materials, with a purity of not less than 99.7 wt.%. The alloying elements such as B, Mg, Si, Cu, La, and Ce are all added in the form of master alloys.

[0026] Another object of the present invention is to provide a preparation method for an age-hardenable aluminum alloy conductor material.

[0027] A preparation method of an age-hardenable aluminum alloy conductor material according to the present invention, the preparation method comprising the following steps: heating the aluminum raw material to 800-900 °C, performing boronization treatment, and then analyzing the composition of the aluminum liquid. When the total content of Ti and V is not higher than 0.002 wt.%, transfer to a converter, charge according to the designed composition, reduce the melt temperature to 700-740 °C, and sequentially add Al-Si, Al-Cu, Al-La / Ce, and Al-Mg master alloys. After the master alloys are melted, perform stirring, refining, in-furnace composition analysis, composition adjustment, and standing, perform casting at 700-720 °C, and then perform hot deformation, online solution treatment and direct cooling quenching, pre-aging, drawing, and artificial aging.

[0028] A preparation method of an age-hardenable aluminum alloy conductor material according to the present invention, the boronization treatment is achieved by adding an Al-B master alloy. The addition amount of the Al-B master alloy is calculated according to 0.7-1.8 times, preferably 1.0-1.5 times, the sum of the masses of Ti and V in the aluminum raw material. During the boronization process, the contents of Ti and V in the aluminum liquid are detected in real time, and the number of boronization treatments is adjusted to remove Ti and V impurity elements, and at the same time control the content of B in the melt to reduce the consumption of La and Ce rare earths by excessive B in the aluminum liquid and the adverse effects on the conductivity. The number of boronization treatments includes but is not limited to 1 time. Further, the boronization treatment uses stirring-assisted boronization to improve the boronization efficiency, including but not limited to stirring methods such as gas, electromagnetic, and ultrasonic, and the stirring time is 10-30 min.

[0029] A preparation method of an age-hardenable aluminum alloy conductor material according to the present invention, the converter operation uses the physical sedimentation method to remove the relatively heavy diboride in the aluminum liquid and purify the aluminum liquid. Further, the converter operation needs to be static after the boronization treatment, and the static time is not less than 30 min to make the generated boride with a specific gravity greater than that of the aluminum liquid settle sufficiently, and only the upper-layer aluminum liquid is taken for subsequent processes. The upper-layer aluminum liquid is 93-97% of the total aluminum liquid volume.

[0030] A preparation method of an age-hardenable aluminum alloy conductor material according to the present invention, in the melt refining process, industrial pure nitrogen is used to blow the refining agent into the melt for degassing and refining. The purity of the industrial pure nitrogen is not less than 99.999%; the refining agent is prepared from powdered KCl and MgCl2, and the addition amount of the refining agent is 0.03-0.05% of the melt mass. The time of the refining process is controlled within 10-20 min.

[0031] A preparation method of an age-hardenable aluminum alloy conductor material according to the present invention, the casting includes but is not limited to ordinary casting, semi-continuous casting, and continuous casting; the hot deformation includes but is not limited to hot extrusion and hot continuous rolling.

[0032] A preparation method of an age-hardenable aluminum alloy conductor material, which utilizes the deformation heat generated by the hot deformation to achieve in-line solution treatment and then directly cool by quenching; the direct cooling after hot extrusion includes, but is not limited to, in-line water spraying and strong wind cooling; the direct cooling during hot continuous rolling is achieved by regulating the emulsion temperature and the cooling water pressure.

[0033] The extrusion temperature of the hot extrusion is 480 - 530 °C, the extrusion speed is 10 - 15 m / min, and the total deformation amount of the aluminum rod is not less than 80%; the direct cooling after the hot extrusion includes, but is not limited to, in-line water spraying and strong wind cooling, and its cooling speed is 20 - 50 °C / s, preferably 20 - 40 °C / s. Specifically, such as 20 °C / s, 25 °C / s, 30 °C / s, 35 °C / s, 40 °C / s.

[0034] The in-line solution treatment during the hot extrusion is achieved by using the deformation heat generated during the hot extrusion to raise the temperature of the aluminum rod above the extrusion temperature and then directly cooling.

[0035] For the hot continuous rolling, the cast billet obtained by casting is cooled to the rolling inlet temperature and then continuously rolled. The rolling inlet temperature is 480 - 530 °C, the emulsion temperature is 20 - 50 °C, the cooling water pressure is 300 - 400 kPa, the cooling water temperature ≤ 35 °C, the final rolling temperature of the aluminum rod ≤ 50 °C, and the total deformation amount of the aluminum rod is not less than 80%.

[0036] The in-line solution treatment during the hot continuous rolling is achieved by using the deformation heat generated during the hot continuous rolling to raise the temperature of the aluminum rod above the rolling inlet temperature and then cooling by regulating the emulsion temperature and the cooling water pressure.

[0037] A preparation method of an age-hardenable aluminum alloy conductor material, wherein the direct cooling changes the cooling medium and temperature according to the performance requirements of the aluminum rod; for the direct cooling of hot extrusion, it includes, but is not limited to, in-line water spraying and strong wind cooling; for the direct cooling of hot continuous rolling, it is achieved by changing the emulsion temperature and the cooling water pressure.

[0038] A preparation method of an age-hardenable aluminum alloy conductor material, for the pre-aging process, the heating rate is 3 - 5 °C / min, the pre-aging temperature is 150 - 180 °C, and the pre-aging time is 1 - 3 h; immediately cool after the pre-aging is completed, and the cooling methods include, but are not limited to, air cooling and water cooling; the air cooling rate ≥ 15 °C / s; the water cooling rate ≥ 20 °C / s. Its purpose is to inhibit the natural aging behavior of the aluminum alloy conductor material, improve the stability of the aluminum alloy during room temperature storage, promote the formation of beneficial atomic clusters in the aluminum alloy conductor material, and synergistically improve the strength and conductivity. The pre-aging process needs to be carried out quickly after the aluminum rod undergoes in-line solution treatment and direct cooling by quenching. Preferably, the pre-aging process is carried out within 10 minutes after the aluminum rod undergoes in-line solution treatment.

[0039] A preparation method of an age - hardenable aluminum alloy conductor material according to the present invention, the drawing process includes but is not limited to continuous drawing, aiming to draw the aluminum rod into single wires. The pass elongation coefficient of the drawing process is 1.1 - 1.5, the wire - drawing speed is 5 - 15 m / s, and grease lubrication is provided during the drawing process to obtain aluminum alloy single wires with a diameter of 2.5 - 4.0 mm. The drawing die matching of the drawing process includes but is not limited to equal - strain dies.

[0040] A preparation method of an age - hardenable aluminum alloy conductor material according to the present invention, for the aging process, oil - bath heat preservation is adopted, the temperature is 170 - 190 °C, the time is 10 - 20 h, and after aging, air cooling is carried out. Its purpose is to further improve the strength and conductivity of the single wires through age hardening, and to improve plasticity and reduce the difficulty of single - wire stranding.

[0041] The beneficial effects of the present invention are as follows:

[0042] (1) Through the reasonable ratio of Mg, Si, Cu, and rare - earth elements in the present invention, combined with stirring - assisted boronization and on - line composition monitoring, purification, modification, and strengthening effects are synergistically generated.

[0043] (2) In the present invention, direct cooling after hot processing realizes on - line solution treatment, and pre - aging treatment is carried out, which provides a driving force for the precipitation of subsequent strengthening phases, inhibits the occurrence of harmful natural aging during room - temperature storage, improves the tissue stability of the aluminum rod, maintains high plasticity, improves drawability, and greatly reduces the probability of wire breakage.

[0044] (3) In the present invention, oil - bath heat preservation is used for artificial aging of single wires, ensuring uniform heating of the inside and outside of the single - wire coil, isolating air, ensuring uniform single - wire performance, avoiding surface oxidation, ensuring surface quality, and at the same time, the surface oil film can improve the damage - resistance performance of single wires.

[0045] (4) After aging treatment, the single wires prepared by the present invention can synergistically improve the strength and conductivity of single wires, improve plasticity, greatly reduce the difficulty of single - wire stranding, and reduce energy consumption. The strength of the prepared single wires > 310 MPa, the elongation rate ≥ 6.3%, the conductivity > 56.1% IACS, which can meet the power - transmission requirements of various service scenarios and has significant energy - saving effects. Description of the Drawings

[0046] Appendix Figure 1 It is a transmission electron micrograph of the strengthening phase in the single wire of Example 6;

[0047] Appendix Figure 2 It is a transmission electron micrograph of the strengthening phase in the single wire of Comparative Example 7.

[0048] Specific embodiments:

[0049] The technical solution of the present invention will be further described below through specific embodiments, which are only for helping to understand the present invention and should not be regarded as a specific limitation to the present invention.

[0050] Examples 1-5 and Comparative Examples 1-6 were set up, and their components are shown in Table 1. The difference between Comparative Example 1 and Example 1 is only in the boronization process. The boronization process used in Comparative Example 1 has no stirring assistance, and the boronization reaction occurs only by the static standing of the aluminum liquid; the difference between Comparative Example 2 and Example 1 is only that Cu is not added; the difference between Comparative Example 3 and Example 1 is only that the La / Ce mixed rare earth is not added; the difference between Comparative Example 4 and Example 1 is only in the Mg / Si ratio; the difference between Comparative Example 5 and Example 1 is only that the Fe content is higher than the upper limit of the content of the present invention; the difference between Comparative Example 6 and Example 1 is only that the Cu content is higher than the upper limit of the content of the present invention.

[0051] Industrial pure aluminum ingots with a purity of 99.7% were used as raw materials to prepare aluminum alloy wires. The industrial aluminum ingots were melted at 760 °C and then heated to 850 °C for boronization treatment. The mass of the aluminum-boron master alloy was calculated as 1.5 times the sum of the masses of Ti and V in the aluminum liquid and used as the addition amount. For the boronization treatment, immediately after adding boron element, industrial pure nitrogen with a purity not lower than 99.999% was blown in for gas stirring, and the stirring time was 10 min. Then the aluminum liquid was allowed to stand for 30 min for converter operation. The temperature of the aluminum liquid after the converter operation was lowered to 720 °C, and Al-Si, Al-Cu, Al-La / Ce (mass ratio of La to Ce is 35:65), and Al-Mg master alloys were added in sequence. After the master alloys were completely melted, mechanical stirring was carried out for 20 min to make the composition of the aluminum liquid uniform. Industrial pure nitrogen with a purity not lower than 99.999% was used to introduce the refining agent into the melt for degassing and refining, and the refining time was 20 min. The scum on the surface of the aluminum liquid was skimmed off, and the aluminum liquid in different regions of the holding furnace was sampled for composition analysis using a direct-reading spectrometer, and the alloy composition was adjusted according to the analysis results. After confirming that the content of each element met the requirements, casting was carried out. The casting temperature was maintained at about 720 °C, and by adjusting the continuous casting cooling water pressure and the casting wheel speed, the billet temperature was controlled to be 530 - 560 °C. Then the continuous casting billet was subjected to hot continuous rolling. The billet entering the rolling mill temperature was 520 °C, the emulsion temperature was 30 °C, the cooling water pressure was 350 kPa, the cooling water temperature was 30 °C, and the final rolling temperature of the aluminum rod was 50 °C to obtain a Ф12 mm aluminum rod.

[0052] Table 1 Alloy element composition ratio table (wt.%)

[0053] Alloying element Mg Si Cu Mg / Si Fe La+Ce rare earth Boronization method Example 1 0.60 0.45 0.08 1.33 ＜0.10 0.2 Gas stirring Example 2 0.60 0.50 0.08 1.20 ＜0.10 0.2 Gas stirring Example 3 0.60 0.50 0.03 1.20 ＜0.10 0.2 Gas stirring Example 4 0.60 0.45 0.08 1.33 ＜0.10 0.2 Gas stirring Example 5 0.60 0.40 0.08 1.50 ＜0.10 0.1 Gas stirring Comparative example 1 0.60 0.45 0.08 1.33 ＜0.10 0.2 Conventional boronization Comparative example 2 0.60 0.45 0 1.33 ＜0.10 0.2 Gas stirring Comparative example 3 0.60 0.45 0.08 1.33 ＜0.10 0 Gas stirring Comparative example 4 0.70 0.30 0.08 2.33 ＜0.10 0.2 Gas stirring Comparative example 5 0.60 0.45 0.08 1.33 0.40 0.2 Gas stirring Comparative example 6 0.60 0.45 0.20 1.33 ＜0.10 0.2 Gas stirring

[0054] The strength of the in-line solutionized aluminum rods prepared from the components of Examples 1-5 and Comparative Examples 1-6 was tested in accordance with GB / T 228.1-2010, and the conductivity at 20 °C of the aluminum rods was tested in accordance with GB / T 12966-2008. The results are shown in Table 2. The difference between Example 1 and Comparative Example 1 is that gas stirring was used to assist boronization in Example 1. The performance comparison between Example 1 and Comparative Example 1 shows that the use of stirring-assisted boronization in the present invention can significantly improve the conductivity of the aluminum alloy; the performance comparison between Example 1 and Comparative Example 2 shows that adding Cu within the composition design range of the present invention can significantly improve the strength of the aluminum alloy without significantly reducing the conductivity; the performance comparison between Example 1 and Comparative Example 3 shows that adding a La / Ce mixed rare earth within the composition design range of the present invention can synergistically improve the strength and conductivity of the alloy; the performance comparison between Example 1 and Comparative Example 4 shows that adding Mg and Si elements within the composition design range of the present invention can achieve a good match between the strength and conductivity of the aluminum rod; the performance comparison between Example 1 and Comparative Example 5 shows that controlling the Fe content below 0.1 wt.% within the composition design range of the present invention can improve the strength of the alloy. The performance comparison between Example 1 and Comparative Example 6 shows that exceeding the composition design range of the Cu content can improve the strength of the alloy but will significantly reduce the conductivity.

[0055] Table 2 Test Results of the Strength and Conductivity of Aluminum Rods

[0056] Test item Strength / MPa Conductivity / %IACS Example 1 177 51.7 Example 2 182 51.4 Example 3 179 51.6 Example 4 176 51.5 Example 5 174 51.4 Comparative example 1 175 49.6 Comparative example 2 169 52.0 Comparative example 3 172 50.0 Comparative example 4 160 52.3 Comparative example 5 167 51.9 Comparative example 6 181 49.5

[0057] To further illustrate the technical advantages of preparing single wires from aluminum rods in the present invention, Ф3.5 mm single wires were prepared according to the technical scheme in Table 3, and the composition ratio of the aluminum alloy used was the composition of Example 1 in Table 2. The in-line solutionization described in Table 3 was achieved by controlling the rolling temperature and cooling water pressure during hot continuous rolling, where the rolling temperature was 520 °C, the emulsion temperature was 30 °C, the cooling water pressure was 350 kPa, the cooling water temperature was 30 °C, and the final rolling temperature was 50 °C to obtain Ф12 mm aluminum rods. For the drawing process, multi-pass continuous drawing was used, the pass elongation coefficient was 1.1-1.5, the drawing speed was 10 m / s, and oil lubrication was used during the drawing process. The artificial aging was carried out in a fire-resistant Si oil medium.

[0058] Table 3 Technical Scheme for Preparing Single Wires from Aluminum Rods

[0059]

[0060]

[0061] The differences among Examples 6 - 9 lie in different aging systems. The difference between Comparative Example 7 and Example 6 is that the pre-aging treatment at 160°C for 3 h was not carried out; the difference between Comparative Example 8 and Example 6 is that the artificial aging temperature was only 150°C, which is not within the range of the artificial aging temperature described in the present invention. Comparative Examples 9 and 10 are technical solutions for preparing single wires from traditional aluminum rods, and the thermal deformation does not control the cooling conditions of the aluminum rods.

[0062] The strength and elongation of the single wires prepared in Examples 6 - 9 and Comparative Examples 7 - 10 were tested according to Standard GB / T 228.1 - 2010, the conductivity at 20°C was tested according to GB / T 12966 - 2008, and the drawability of the aluminum rods for preparing wires was evaluated by the number of broken wires that occurred during the drawing of a single coil of aluminum rod. The results are shown in Table 4. The weight of one coil of the product in Table 4 is about 2 tons.

[0063] Table 4 Test Results of Single Wire Properties

[0064] Test item Strength / MPa Elongation / % Conductivity / %IACS Wire breakage rate / (times / roll) Example 6 315 6.0 55.8 ≤1 Example 7 312 6.3 56.1 ≤1 Example 8 307 6.8 56.2 ≤1 Example 9 305 6.4 55.9 ≤1 Comparative example 7 295 7.0 55.5 / Comparative example 8 305 6.2 54.8 / Comparative example 9 292 6.0 54.6 / Comparative example 10 357 2.0 55.2 ＞10

[0065] As can be seen from Table 4, the comprehensive properties of the single wires prepared in Examples 6 - 9 of the present invention are superior to those of Comparative Examples 7 - 10. The performance comparison between Example 6 and Comparative Example 7 shows that the pre-aging process adopted in the present invention can synergistically improve the strength and conductivity of the single wire; Figure 1 and Figure 2 are TEM photos of Example 6 and Comparative Example 7 of the present invention respectively. It can be seen that the density of the strengthening phase inside the single wire described in Example 6 is greater, indicating that pre-aging makes the precipitation of Mg and Si elements more complete. The performance comparison between Example 6 and Comparative Example 8 shows that when the artificial aging temperature of the single wire is lower than the artificial aging temperature of the present invention, the strength and conductivity of the single wire decrease. The comparison between Examples 6 - 9 and Comparative Examples 9 and 10 shows that the technical solutions for preparing single wires in the present invention are significantly superior to the traditional technical solutions. The wire breakage rate of Comparative Example 10 is significantly higher than that of the examples, indicating that performing artificial aging treatment first will significantly reduce the drawability of round aluminum rods, and the elongation of the single wires of the prepared wires is also significantly lower than that of the examples. Therefore, the technical solution of Comparative Example 10 is not suitable for industrial production.

[0066] In summary, through the reasonable proportioning and synergistic effect of elements such as Al, B, Si, Cu, Mg, La, and Ce, and by adopting the stirring-assisted boronization treatment process, high-quality aluminum liquid is obtained. By using the hot deformation cooling process, an aluminum rod supersaturated with Mg and Si atoms is obtained, and combined with the pre-aging process, the occurrence of harmful natural aging of the aluminum alloy conductor material is inhibited, and the room-temperature storage stability is improved. The single wire prepared by continuous drawing is obtained through single-stage aging to obtain a single wire product with a matching strength and conductivity. The tensile strength of the single wire is ≥305 MPa, the elongation is ≥6%, and the conductivity is ≥55.8% IACS. After optimization, the tensile strength of the single wire is >310 MPa, the elongation is ≥6.3%, and the conductivity is >56.1% IACS, which can meet the power transmission requirements of various service scenarios, and the energy-saving effect of production and application is remarkable.

[0067] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can also be made, which should also be regarded as the protection scope of the present invention.

Claims

1. An age-hardenable aluminum alloy conductor material, characterized in that, The aluminum alloy comprises the following components by mass percentage: Mg: 0.50 - 0.90 wt.%; Si: 0.40 - 0.80 wt.%; Cu: 0.03 - 0.15 wt.%; Mixed rare earths of La and Ce: 0.10 - 0.30 wt.%; The balance is aluminum and inevitable impurity elements; The age - hardenable aluminum alloy conductor material is prepared by the following steps: Using industrial pure aluminum ingots and / or primary aluminum liquid as raw materials, carrying out boronizing treatment, adding master alloys, melting and refining, in - furnace component analysis, component adjustment, casting and hot deformation, online solution treatment and direct cooling quenching, pre - aging, drawing, and artificial aging; The casting includes but is not limited to ordinary casting, semi - continuous casting, and continuous casting; the hot deformation includes but is not limited to hot extrusion and hot continuous rolling; For the hot extrusion, the extrusion temperature is 480 - 530 °C, the extrusion speed is 10 - 15 m / min, and the total deformation amount of the aluminum rod is not less than 80%; the direct cooling after hot extrusion includes but is not limited to online water spraying and strong - wind cooling, and its cooling speed is 20 - 50 °C / s; The online solution treatment during the hot extrusion process is realized by using the deformation heat generated during the hot extrusion process to raise the temperature of the aluminum rod above the extrusion temperature and then directly cooling; For the hot continuous rolling, the cast billet obtained by casting is cooled to the rolling - entry temperature and then continuously rolled. The rolling - entry temperature is 480 - 530 °C, the emulsion temperature is 20 - 50 °C, the cooling water pressure is 300 - 400 kPa, the cooling water temperature ≤ 35 °C, the final rolling temperature of the aluminum rod ≤ 50 °C, and the total deformation amount of the aluminum rod is not less than 80%; The online solution treatment during the hot continuous rolling process is realized by using the deformation heat generated during the hot continuous rolling process to raise the temperature of the aluminum rod above the rolling - entry temperature and then cooling by regulating the emulsion temperature and the cooling water pressure; For the pre - aging, the heating rate is 3 - 5 °C / min, the temperature is 150 - 180 °C, and the time is 1 - 3 h; the pre - aging needs to be carried out rapidly after the aluminum rod has undergone online solution treatment; For the artificial aging, oil - bath heat preservation is adopted, the temperature is 170 - 190 °C, and the time is 10 - 20 h.

2. The age-hardenable aluminum alloy conductor material according to claim 1, characterized in that, The aluminum alloy comprises the following components by mass percentage: Mg: 0.55 - 0.90 wt.%; Si: 0.40 - 0.75 wt.%; Cu: 0.03 - 0.10 wt.%; Mixed rare earths of La and Ce: 0.15 - 0.25 wt.%; The balance is aluminum and inevitable impurity elements; Among them, the mass ratio of the Mg and Si elements is 0.9 - 1.8; the residual amount of B element in the inevitable impurity elements is less than 0.005 wt.%, the content of Fe element is less than 0.1 wt.%, and the total content of Ti, V, Cr, and Mn is less than 0.010 wt.%.

3. The age-hardenable aluminum alloy conductor material according to claim 1, characterized in that: The addition amount of boron and the number of boronizing treatments in the boronizing treatment are determined according to the Ti and V contents in the aluminum liquid; the boronizing treatment improves the boronizing efficiency by stirring and reduces the residual amount of B element in the aluminum liquid; the stirring methods include but are not limited to gas, electromagnetic, and ultrasonic stirring methods.

4. The age-hardenable aluminum alloy conductor material according to claim 1, characterized in that: The drawing process includes, but is not limited to, continuous drawing, aiming to draw the aluminum rod into single wires. The pass elongation coefficient of the drawing process is 1.1 - 1.5, the wire drawing speed is 5 - 15 m / s, and grease lubrication is provided during the drawing process to obtain aluminum alloy single wires with a diameter of 2.5 - 4.0 mm.

5. The age-hardenable aluminum alloy conductor material according to any one of claims 1-4, characterized in that: The strength of the prepared single wire is > 310 MPa, the elongation is ≥ 6.3%, and the conductivity is > 56.1% IACS.

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