High-performance aluminum alloy strip for cables and method for producing same

Abstract

This application relates to a high-performance aluminum alloy strip for cables and its preparation method. The high-performance aluminum alloy strip for cables is a single-layer aluminum alloy strip, comprising the following components by mass percentage: rare earth elements 0.05-0.15 wt%, B 0.003-0.015 wt%, Si ≤0.1 wt%, Fe ≤0.15 wt%, other impurity elements ≤0.05 wt%, and the balance being Al. This application has the effect of improving the conductivity and mechanical strength of the aluminum alloy strip.

Description

Technical Field

[0001] This application relates to the field of aluminum alloys, and in particular to a high-performance aluminum alloy strip for cables and a method for preparing the same. Background Technology

[0002] Aluminum and aluminum alloys have the characteristics of low density, good processing performance and excellent conductivity, and are widely used in overhead conductors, power cables and new energy transmission and distribution lines. Most existing cable conductor materials use 1XXX series industrial pure aluminum. These materials have low impurity content and can meet the conductivity requirements of general power transmission scenarios. However, with the continuous expansion of long-distance power transmission, new energy grid connection and infrastructure construction, cable conductors not only need to maintain low resistivity, but also need to have higher tensile strength, thermal stability and service reliability.

[0003] Currently, to improve the conductivity of aluminum conductors, the common approach is to increase the purity of the molten aluminum and reduce the content of impurity elements such as iron and silicon. However, under industrial smelting conditions, impurity elements are difficult to completely remove, and residual impurities can easily form a second phase or dissolve in the aluminum matrix, increasing electron scattering and thus affecting conductivity. On the other hand, if alloying elements are added to increase the material's strength, the conductivity can easily decrease due to solid solution strengthening or increased precipitates, making it difficult to balance strength improvement with maintaining conductivity. Summary of the Invention

[0004] In order to improve the conductivity and strength of aluminum alloy strips, this application provides a high-performance aluminum alloy strip for cables and a method for preparing the same.

[0005] Firstly, this application provides a high-performance aluminum alloy strip for cables, which adopts the following technical solution: A high-performance aluminum alloy strip for cables, wherein the aluminum alloy strip is a single-layer aluminum alloy strip, and the aluminum alloy strip comprises the following components by mass percentage: rare earth element components 0.05-0.15wt%, B 0.003-0.015wt%, Si≤0.1wt%, Fe≤0.15wt%, total amount of other impurity elements ≤0.05wt%, and the balance being Al.

[0006] By adopting the above technical solution, limiting the content range of single-layer aluminum alloy strips and rare earth element components, B, Si, Fe and impurity elements, it is possible to control impurity elements that affect conductivity and microstructure stability while maintaining the low alloying characteristics of 1-series aluminum alloys. When the Si and Fe contents are high, they are prone to forming coarse second phases or dissolving in the aluminum matrix, increasing electron scattering and affecting rolling stability. Introducing rare earth elements and B allows the rare earth element components to regulate the existence state of impurity elements such as Si and Fe. B is mainly used to fix and weaken the adverse effects of transition metal impurities. The synergy of the two improves the purity and microstructure of the aluminum matrix at a lower alloying degree, further improving the conductivity and strength of the aluminum alloy strip.

[0007] Preferably, the rare earth element composition includes Ce and La, and the mass ratio of Ce to La is (2-3.5):1.

[0008] By adopting the above technical solutions, both Ce and La can interact with impurity elements in the aluminum melt. When the Ce content is high, it is beneficial to enhance the regulation of the state of impurity elements such as Fe and Si. The introduction of La helps to improve the inclusion morphology and rare earth-related second phase distribution. Preferably, the mass ratio of Ce to La is within the above range, which can achieve a good balance between purification effect, structural stability and cost.

[0009] Preferably, the aluminum alloy strip also contains 0.01-0.05 wt% Zr.

[0010] By adopting the above technical solution, the tendency of trace Zr to form a dispersed phase in the aluminum matrix is ​​utilized to improve the microstructure stability of aluminum alloy strips during hot working, cold rolling, and subsequent annealing. When the Zr content is in a low range, it mainly plays a role in inhibiting abnormal growth of recrystallized grains and improving thermal stability, and will not significantly improve the degree of alloying as much as high-content strengthening elements.

[0011] Preferably, the aluminum alloy strip also contains Sc, and the mass ratio of the rare earth element component to Sc is (3.3-4.3):1.

[0012] By adopting the above technical solution, after introducing Sc, Sc participates in the microstructure regulation of the aluminum matrix as a trace microstructure stabilizing element. In addition, the mass ratio between rare earth element components and Sc is preferably within the above range, so that Ce / La can mainly play the role of melt purification and impurity regulation, while Sc mainly plays the role of microstructure stabilization, avoiding the problem of a single element playing multiple roles and thus resulting in excessive dosage.

[0013] Preferably, the aluminum alloy strip also contains Ca, and the mass ratio of the rare earth element components, B and Ca is (12-18):1.5:1.

[0014] By adopting the above technical solution, introducing Ca and controlling the rare earth element composition and the mass ratio between B and Ca within the above range, a more complete multi-path purification system can be formed. Ca helps to improve the morphology of oxide inclusions, sulfide inclusions and some Fe and Si related phases in aluminum melt, making the inclusions or second phases tend to be smaller and more dispersed, reducing the impact of coarse inclusions on rolling processing and subsequent service stability.

[0015] Secondly, this application provides a method for preparing high-performance aluminum alloy strip for cables, employing the following technical solution: A method for preparing a high-performance aluminum alloy strip for cables includes the following steps: S1. Melt purification: The raw materials are melted to obtain aluminum melt, which is then refined and degassed. Subsequently, intermediate alloy B is added for purification treatment, followed by slag removal and filtration to obtain pretreated aluminum melt. S2. Rare earth element component addition: Rare earth element components are added to the aluminum melt after filtration and settling stage, and then casting is carried out. After casting is completed, the ingot gate is sawn off to obtain the ingot. S3. Milling and heating: Mill the two large surfaces of the ingot, then heat, hold, and remove from the furnace to obtain the heated ingot; S4. Rolling: The heated ingot is hot-rolled to obtain aluminum coil blanks, and then cold-rolled to obtain rolled coils. S5. Annealing and shearing: The rolled coil is annealed to the O state in an annealing furnace, and then sheared after exiting the furnace to obtain a high-performance aluminum alloy strip for cables.

[0016] Preferably, in step S1, the melting temperature is 760-780℃, the refining and degassing temperature is 750-760℃, and the hydrogen content in the aluminum melt after refining and degassing is ≤0.15ml / 100g Al.

[0017] By adopting the above technical solution, the temperature of melting and refining degassing in step S1 is limited to the above range, and the hydrogen content of the aluminum melt after refining degassing is within the above range, which can improve the melt purification effect and the stability of ingot quality. When the melting temperature is too low, alloying elements and intermediate alloys are not easy to fully melt and distribute evenly. When the temperature is too high, it may increase the risk of oxidation loss and gas absorption. Controlling the hydrogen content after refining degassing is beneficial to reducing the risk of defects such as pinholes and porosity in ingots, and provides a more stable billet base for subsequent hot rolling, cold rolling and annealing.

[0018] Preferably, in step S5, the annealing temperature is 360-380℃, the annealing holding time is 3-5h, and the furnace is cooled for 10-12h after annealing before being removed from the furnace.

[0019] By adopting the above technical solutions, and preferably keeping the annealing temperature and holding time within the aforementioned ranges, the dislocations and internal stresses introduced by cold rolling are released, promoting microstructure recovery and recrystallization. When the annealing temperature and holding time are within these ranges, it helps reduce the adverse effects of microstructure distortion and electron scattering caused by cold working. Simultaneously, it avoids residual internal stress due to insufficient annealing, or abnormal grain growth, decreased strength, and poor sheet shape stability due to over-annealing. Furnace cooling can reduce thermal stress differences caused by rapid cooling, improving the dimensional stability and subsequent processing adaptability of the aluminum alloy strip.

[0020] Preferably, in step S5, nitrogen protection is used throughout the annealing process.

[0021] By adopting the above technical solution and using nitrogen protection throughout the annealing process, the surface oxidation of aluminum alloy strips during high-temperature annealing can be reduced, thus minimizing the impact of oxide film thickening, surface discoloration, or surface defects on subsequent slitting, packaging, and cable applications.

[0022] In summary, this application includes at least one of the following beneficial technical effects: By constructing a composition system of low-impurity aluminum matrix, Ce / La composite rare earth and trace amount of B, and further controlling the content of impurity elements, the rare earth element components and B play a purifying and regulating role for different types of impurities, reducing the adverse effects of impurity elements on the aluminum matrix structure and conductivity, thereby taking into account the conductivity, mechanical properties and processing stability of aluminum alloy strip for cables at a lower degree of alloying. Further introduction of trace elements such as Ca, Zr and / or Sc, where Ca is used to help improve the morphology of inclusions and second phases, and Zr and Sc are used to improve the microstructure stability during cold rolling and annealing. The added trace elements play a role in melt purification, inclusion control and recrystallization microstructure stability, which is beneficial to improving the microstructure uniformity and long-term service stability of aluminum alloy strips. After refining and degassing, B intermediate alloy is added. After slag removal and filtration, rare earth element components are added in the later stage of the settling phase. Combined with milling, hot rolling, cold rolling, nitrogen-protected annealing and furnace cooling processes, the composition design and preparation process are synergistic, reducing rare earth burn-off and ineffective losses, reducing ingot defects and cold rolling internal stress, and improving the surface quality, microstructure stability and batch production consistency of aluminum alloy strip. Detailed Implementation

[0023] The present application will be further described in detail below with reference to the embodiments: Raw material description: All raw materials used in the examples are commercially available. Example 1

[0024] Preparation of high-performance aluminum alloys for cables: Prepare the raw materials according to the following proportions: Rare earth element composition: 0.05wt%, B: 0.0045wt%, Sc: 0.0116wt%, Ca: 0.0030wt%, Zr: 0.01wt%, Si: 0.005wt%, Fe: 0.05wt%, other impurity elements total 0.01wt%, balance Al; wherein, the rare earth element composition is Ce and La in a mass ratio of 2:1; the mass ratio of rare earth element composition to Sc is 4.3:1; the mass ratio of rare earth element composition, B and Ca is 16.7:1.5:1.

[0025] S1. Melt Purification: Raw materials are added to the melting furnace according to the required proportions and melted at a temperature of 760℃. The melting is completed by stirring for 30 minutes. After melting, the material is refined and degassed at a temperature of 750℃ for 30 minutes. The hydrogen content of the refined liquid aluminum is 0.1 mL / 100g Al. Then, intermediate alloy B is added and the mixture is stirred at low speed for 10 minutes for purification. Finally, the material is skimmed off and filtered to obtain pretreated aluminum melt. S2. Rare earth element component addition: After filtration, the pretreated aluminum melt is allowed to stand for 40 minutes. Rare earth element components are added during the last 15 minutes of standing. Then casting is carried out at a casting temperature of 670℃, a casting speed of 50mm / min, a cooling water flow rate of 2900L / min, and a water temperature of 20℃. After casting, 150mm of the ingot gate is sawn off to obtain the ingot. S3. Milling and heating: Mill the two large surfaces of the ingot by 7.5 mm per surface, then heat, hold and remove from the furnace. The heating temperature is 520℃ and the holding time is 14h. After removing from the furnace, the heated ingot is obtained. S4. Rolling: The heated ingot is hot rolled through a hot rolling mill to obtain an aluminum coil blank with a thickness of 4.0 mm. Then, it is cold rolled to obtain a rolled coil with a thickness of 0.20 mm. S5. Annealing and shearing: The rolled coil is annealed to the O state in an annealing furnace. During annealing, the temperature of the rolled coil is controlled at 360℃ and the holding time is 5h. Nitrogen protection is used throughout the process. After annealing, the coil is cooled in the furnace for 10h and then removed from the furnace. After removal from the furnace, it is sheared to obtain high-performance aluminum alloy strip for cables. Example 2

[0026] Preparation of high-performance aluminum alloys for cables: Prepare the raw materials according to the following proportions: Rare earth element composition: 0.15wt%, B: 0.015wt%, Sc: 0.035wt%, Ca: 0.010wt%, Zr: 0.05wt%, Si: 0.10wt%, Fe: 0.15wt%, other impurity elements total 0.05wt%, balance Al; wherein, the rare earth element composition is Ce and La in a mass ratio of 3.5:1; the mass ratio of rare earth element composition to Sc is 4.3:1; the mass ratio of rare earth element composition, B and Ca is 15:1.5:1.

[0027] S1. Melt Purification: Raw materials are added to the melting furnace according to the required proportions and melted at a temperature of 780℃. The melting is completed by stirring for 20 minutes. After melting, the material is refined and degassed at a temperature of 760℃ for 20 minutes. The hydrogen content of the refined liquid aluminum is 0.15mL / 100g Al. Then, intermediate alloy B is added and the mixture is stirred at low speed for 20 minutes for purification. Finally, the material is skimmed off and filtered to obtain pretreated aluminum melt. S2. Rare earth element component addition: After filtration, the pretreated aluminum melt is allowed to stand for 40 minutes. Rare earth element components are added during the last 20 minutes of standing. Then casting is carried out at a casting temperature of 700℃, a casting speed of 30mm / min, a cooling water flow rate of 3000L / min, and a water temperature of 30℃. After casting, 200mm of the ingot gate is sawn off to obtain the ingot. S3. Milling and heating: Mill the two large surfaces of the ingot by 10mm per surface, then heat, hold and remove from the furnace. The heating temperature is 540℃ and the holding time is 10h. After removing from the furnace, the heated ingot is obtained. S4. Rolling: The heated ingot is hot rolled through a hot rolling mill to obtain an aluminum coil blank with a thickness of 5.0 mm. Then, it is cold rolled to obtain a rolled coil with a thickness of 0.30 mm. S5. Annealing and shearing: The rolled coil is annealed to the O state in an annealing furnace. During annealing, the temperature of the rolled coil is controlled at 380℃ and the holding time is 3h. Nitrogen protection is used throughout the process. After annealing, the coil is cooled in the furnace for 12h and then removed from the furnace. After removal from the furnace, it is sheared to obtain high-performance aluminum alloy strip for cables. Example 3

[0028] Preparation of high-performance aluminum alloys for cables: Prepare the raw materials according to the following proportions: Rare earth element composition: 0.10 wt%, B: 0.009 wt%, Sc: 0.026 wt%, Ca: 0.006 wt%, Zr: 0.03 wt%, Si: 0.03 wt%, Fe: 0.08 wt%, other impurity elements total 0.008 wt%, balance Al; wherein, the rare earth element composition is Ce and La in a mass ratio of 2.8:1; the mass ratio of rare earth element composition to Sc is 3.8:1; the mass ratio of rare earth element composition, B and Ca is 16.7:1.5:1.

[0029] S1. Melt Purification: Raw materials are added to the melting furnace according to the required proportions and melted at a temperature of 770℃. The melting is completed by stirring for 25 minutes. After melting, the material is refined and degassed at a temperature of 755℃ for 25 minutes. The hydrogen content of the refined liquid aluminum is 0.12 mL / 100g Al. Then, intermediate alloy B is added and the mixture is stirred at low speed for 15 minutes for purification. Finally, the material is skimmed off and filtered to obtain pretreated aluminum melt. S2. Rare earth element component addition: After filtration, the pretreated aluminum melt is allowed to stand for 40 minutes. Rare earth element components are added during the last 18 minutes of standing. Then casting is carried out at a casting temperature of 685℃, a casting speed of 40mm / min, a cooling water flow rate of 2950L / min, and a water temperature of 25℃. After casting, 180mm of the ingot gate is sawn off to obtain the ingot. S3. Milling and heating: Mill the two large surfaces of the ingot by 8.8 mm per surface, then heat, hold and remove from the furnace. The heating temperature is 530℃ and the holding time is 12h. After removing from the furnace, the heated ingot is obtained. S4. Rolling: The heated ingot is hot rolled through a hot rolling mill to obtain an aluminum coil blank with a thickness of 4.5mm. Then, it is cold rolled to obtain a rolled coil with a thickness of 0.25mm. S5. Annealing and shearing: The rolled coil is annealed to the O state in an annealing furnace. During annealing, the temperature of the rolled coil is controlled at 370℃ and the holding time is 4h. Nitrogen protection is used throughout the process. After annealing, the coil is cooled in the furnace for 11h and then removed from the furnace. After removal from the furnace, it is sheared to obtain high-performance aluminum alloy strip for cables. Example 4

[0030] Example 4 is based on Example 3. The difference between Example 4 and Example 3 is that in the rare earth element composition of Example 4, the mass ratio of Ce to La is 1.5:1. Example 5

[0031] Example 5 is based on Example 3. The difference between Example 5 and Example 3 is that in the rare earth element composition of Example 5, the mass ratio of Ce to La is 4:1. Example 6

[0032] Example 6 is based on Example 3. The difference between Example 6 and Example 3 is that the Zr content in Example 6 is 0.005wt%. Example 7

[0033] Example 7 is based on Example 3. The difference between Example 7 and Example 3 is that the Zr content in Example 7 is 0.1 wt%. Example 8

[0034] Example 8 is based on Example 3. The difference between Example 8 and Example 3 is that the mass ratio of rare earth element components to Sc in Example 8 is 2:1. Example 9

[0035] Example 9 is based on Example 3. The difference between Example 9 and Example 3 is that the mass ratio of rare earth element components to Sc in Example 9 is 5.5:1. Example 10

[0036] Example 10 is based on Example 3. The difference between Example 10 and Example 3 is that in Example 10, the mass ratio of rare earth element components, B and Ca is 8:1.5:1. Example 11

[0037] Example 11 is based on Example 3. The difference between Example 11 and Example 3 is that in Example 11, the mass ratio of rare earth element components, B and Ca is 22:1.5:1. Example 12

[0038] Example 12 is based on Example 3. The difference between Example 12 and Example 3 is that Zr is not added in Example 12. Example 13

[0039] Example 13 is based on Example 3. The difference between Example 13 and Example 3 is that Sc is not added in Example 13. Example 14

[0040] Example 14 is based on Example 3. The difference between Example 14 and Example 3 is that Ca is not added in Example 14. Example 15

[0041] Example 15 is based on Example 3. The difference between Example 15 and Example 3 is that in step S1 of Example 15, the melting temperature is 720°C. Example 16

[0042] Example 16 is based on Example 3. The difference between Example 16 and Example 3 is that in step S1 of Example 16, the melting temperature is 790°C. Example 17

[0043] Example 17 is based on Example 3. The difference between Example 17 and Example 3 is that in step S1 of Example 17, the refining and degassing temperature is 710°C. Example 18

[0044] Example 18 is based on Example 3. The difference between Example 18 and Example 3 is that in step S1 of Example 18, the refining and degassing temperature is 800°C. Example 19

[0045] Example 19 is based on Example 3. The difference between Example 19 and Example 3 is that in step S1 of Example 19, the hydrogen content in the aluminum melt after refining and degassing is 0.20 ml / 100 g Al. Example 20

[0046] Example 20 is based on Example 3. The difference between Example 20 and Example 3 is that in step S5 of Example 20, the annealing temperature is 330°C. Example 21

[0047] Example 21 is based on Example 3. The difference between Example 21 and Example 3 is that in step S5 of Example 21, the annealing temperature is 410°C. Example 22

[0048] Example 22 is based on Example 3. The difference between Example 22 and Example 3 is that in step S5 of Example 22, the annealing and heat preservation time is 2 hours. Example 23

[0049] Example 23 is based on Example 3. The difference between Example 23 and Example 3 is that in step S5 of Example 23, the annealing and heat preservation time is 6 hours. Example 24

[0050] Example 24 is based on Example 3. The difference between Example 24 and Example 3 is that nitrogen protection was not used during annealing in step S5 of Example 24. Example 25

[0051] Example 25 is based on Example 3. The difference between Example 25 and Example 3 is that in Example 25, the rare earth element component is added when the raw materials are melted to obtain aluminum melt.

[0052] Comparative Example 1 Comparative Example 1 is based on Example 3, and the rare earth element component in Comparative Example 1 contains only Ce.

[0053] Comparative Example 2 Comparative Example 2 is based on Example 3, and the rare earth element component in Comparative Example 2 contains only La.

[0054] Comparative Example 3 Comparative Example 3 is based on Example 3, but no rare earth element components were added in Comparative Example 3, and the balance was made up with Al.

[0055] Comparative Example 4 Comparative Example 4 is based on Example 3, but without the addition of intermediate alloy B.

[0056] Performance testing The following performance tests were performed on the samples of Examples 1-25 and Comparative Examples 1-4: (1) Conductivity detection Using GB / T 12966-2022 as the testing standard, the conductivity of the samples was tested. Each sample was tested 3 times, and the average value was taken. The test results were recorded in Table 1. (2) Tensile strength test Using GB / T 228.1-2021 as the testing standard, the tensile strength and elongation after fracture of the samples were tested. Each sample was tested 3 times, and the average value was taken. The test results were recorded in Table 1. Table 1 Performance test results of Examples 1-25 and Comparative Examples 1-4

[0057]

[0058] The electrical conductivity of Examples 1-3 is 62% or higher, the tensile strength is 90 MPa or higher, and the elongation after fracture is between 25-28%, indicating that the aluminum alloys prepared in this application have good electrical conductivity and mechanical strength.

[0059] In Examples 4 and 5, the mass ratio between the rare earth element components Ce and La is not within the range specified in this application. When the Ce content is insufficient, the adjustment effect on the phase morphology of Fe and Si related impurities is insufficient. When the Ce content is too high, the local rare earth enriched phase increases, forming a coarse second phase. Therefore, the performance of Examples 4 and 5 has decreased.

[0060] In Examples 6 and 7, the Zr content is not within the range specified in this application. When the Zr content is insufficient, a stable dispersed phase cannot be fully formed, resulting in increased grain size and decreased strength after annealing. When the Zr content is too high, although the strength increases, excessive dispersed phase and interface will increase electron scattering and reduce plasticity.

[0061] In Examples 8 and 9, the mass ratio between the rare earth element components and Sc is not within the range specified in this application. When Sc is relatively excessive, the strengthening effect is enhanced, but the conductivity and plasticity decrease. When Sc is insufficient, the dispersion strengthening and recrystallization stabilization effects are insufficient, so the performance of Examples 8 and 9 decreases.

[0062] In Examples 10 and 11, the rare earth element composition and the mass ratio between B and Ca both decreased. When Ca was relatively excessive, more oxides, sulfides and Ca-related complex inclusions were formed. The increase or coarsening of inclusion particles would disrupt the continuity of the matrix and increase electron scattering, affecting the conductivity. When Ca was relatively insufficient, the modification effect on the inclusion morphology was limited, and some oxide inclusions still had sharp and coarse morphologies, resulting in a decrease in the uniformity of the structure.

[0063] In Example 12, no Zr was added, which made it difficult to improve the stabilizing effect on the recrystallized structure. After annealing, the grains grew and the stability decreased.

[0064] In Example 13, no Sc was added, resulting in the lack of a Sc-Zr composite dispersion strengthening core, making it difficult to form a fine and stable composite dispersion phase, thus reducing the strength.

[0065] In Example 14, no Ca was added, resulting in insufficient improvement in inclusion morphology. Local inclusions formed crack initiation sites, leading to performance degradation.

[0066] In steps S1 of Examples 15 and 16, the melting temperature is outside the range. When the melting temperature is insufficient, some intermediate alloys are not fully melted and diffused, the dispersion uniformity of each element in the melt is poor, the stability is insufficient, and the performance is reduced. When the melting temperature is too high, the risk of aluminum melt oxidation and gas absorption is increased, and the loss of trace elements is aggravated, forming more oxide inclusions.

[0067] In Examples 17 and 18, the refining and degassing temperatures were not within the range specified in this application. When the refining and degassing temperature was insufficient, the refining reaction efficiency, bubble rising and inclusion aggregation removal effects were insufficient, and there was too much residual hydrogen and inclusions. When the refining and degassing temperature was too high, it aggravated the formation of oxide film and the burning loss of trace elements, and the oxidation inclusions increased.

[0068] In Example 19, the high hydrogen content in the refined and degassed aluminum melt can cause pores or looseness during solidification, affecting the stability of the material.

[0069] In Examples 20 and 21, the annealing temperatures are not within the range specified in this application. After cold rolling, the material has a high internal dislocation density and large residual stress. When the annealing temperature is insufficient, recovery and recrystallization are inadequate, and dislocations and internal stresses are still largely retained. When the annealing temperature is too high, the grains further grow and coarsen, and the structural stability decreases.

[0070] In Examples 22 and 23, the annealing holding time is not within the range specified in this application. When the annealing holding time is insufficient, recrystallization is incomplete, the residual dislocation density is high, and the electrical conductivity decreases. When the annealing holding time is too long, the microstructure becomes excessively softened and the grains grow, resulting in decreased microstructure stability.

[0071] In Example 24, nitrogen protection was not used in the annealing step, making it easier for an oxide film to form on the surface of the aluminum alloy strip. Trace elements were also more likely to undergo surface oxidation or local burn-off, resulting in a decrease in surface quality and structural stability.

[0072] In Example 25, the rare earth element components were added when the raw materials were melted to obtain aluminum melt. If the rare earth elements were added too early, they would undergo oxidation and burn-off during the subsequent refining, slag removal and filtration processes, and be removed by slag removal or carried out by filtration after combining with inclusions, resulting in a reduction in the actual effective rare earth content.

[0073] Comparative Example 1 contains only Ce, and Comparative Example 2 contains only La. Both lack the complementary effect between Ce-La composite rare earth elements. Although Ce alone helps to regulate Fe / Si impurity phases, its comprehensive effect on inclusion morphology and grain boundary purification is insufficient. La alone has a certain effect on improving some inclusions, but its ability to regulate Fe / Si phases is weaker than that of composite rare earth elements.

[0074] In Comparative Example 3, no rare earth elements were added. Impurities such as Fe and Si were more likely to exist in solid solution, coarse second phase, or grain boundary segregation, which increased electron scattering and formed crack initiation sites, resulting in decreased performance.

[0075] In Comparative Example 4, without the addition of B, transitional impurities were more likely to exist in the aluminum matrix in the form of solid solution or unfavorable second phase, which reduced conductivity and also affected the stability of the material.

[0076] This specific embodiment is merely an explanation of this application and is not intended to limit it. Based on the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of this application. The technical scope of this application is not limited to the contents of the specification but must be determined according to the scope of the claims.

Claims

1. A high-performance aluminum alloy strip for cables, characterized in that: The aluminum alloy strip is a single-layer aluminum alloy strip, and by mass percentage, the aluminum alloy strip comprises the following components: rare earth element components 0.05-0.15wt%, B 0.003-0.015wt%, Si≤0.1wt%, Fe≤0.15wt%, total amount of other impurity elements ≤0.05wt%, and the balance is Al.

2. The high-performance aluminum alloy strip for cables according to claim 1, characterized in that: The rare earth element composition includes Ce and La, and the mass ratio of Ce to La is (2-3.5):

1.

3. The high-performance aluminum alloy strip for cables according to claim 1, characterized in that: The aluminum alloy strip also contains 0.01-0.05 wt% Zr.

4. The high-performance aluminum alloy strip for cables according to claim 1, characterized in that: The aluminum alloy strip also contains Sc, and the mass ratio of the rare earth element component to Sc is (3.3-4.3):

1.

5. The high-performance aluminum alloy strip for cables according to claim 1, characterized in that: The aluminum alloy strip also contains Ca, and the mass ratio of the rare earth element components, B and Ca is (12-18):1.5:

1.

6. A method for preparing a high-performance aluminum alloy strip for cables according to any one of claims 1-5, characterized in that: Includes the following steps: S1. Melt purification: The raw materials are melted to obtain aluminum melt, which is then refined and degassed. Subsequently, intermediate alloy B is added for purification treatment, followed by slag removal and filtration to obtain pretreated aluminum melt. S2. Rare earth element component addition: Rare earth element components are added to the aluminum melt after filtration and settling stage, and then casting is carried out. After casting is completed, the ingot gate is cut off to obtain the ingot. S3. Milling and heating: Mill the two large surfaces of the ingot, then heat, hold, and remove from the furnace to obtain the heated ingot; S4. Rolling: The heated ingot is hot-rolled to obtain aluminum coil blanks, and then cold-rolled to obtain rolled coils. S5. Annealing and shearing: The rolled coil is annealed to the O state in an annealing furnace, and then sheared after exiting the furnace to obtain a high-performance aluminum alloy strip for cables.

7. The method for preparing a high-performance aluminum alloy strip for cables according to claim 6, characterized in that: In step S1, the melting temperature is 760-780℃, the refining and degassing temperature is 750-760℃, and the hydrogen content in the aluminum melt after refining and degassing is ≤0.15ml / 100g Al.

8. The method for preparing a high-performance aluminum alloy strip for cables according to claim 6, characterized in that: In step S5, the annealing temperature is 360-380℃, the annealing holding time is 3-5h, and after annealing, the furnace is cooled for 10-12h before being removed from the furnace.

9. The method for preparing a high-performance aluminum alloy strip for cables according to claim 8, characterized in that: In step S5, nitrogen protection is used throughout the annealing process.

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