High-strength corrosion-resistant low-carbon recycled aluminum alloy and preparation method thereof

Abstract

The application relates to a high-strength corrosion-resistant low-carbon recycled aluminum alloy and a preparation method thereof, and belongs to the technical field of recycled aluminum alloys, and comprises the following steps: S1, raw material selection and crushing to obtain pretreated waste aluminum material; S2, smelting: the pretreated waste aluminum material is put into a smelting furnace to obtain an alloy melt; S3, refining to obtain a pure melt; S4, casting: the temperature of the pure melt is adjusted to 680 DEG C to 720 DEG C, a grain refiner and a rare earth refiner are added, and a semi-continuous casting method is used to cast into an ingot; and S5, sawing: the ingot is subjected to homogenization treatment and then sawed according to the specification requirements. The high-strength corrosion-resistant low-carbon recycled aluminum alloy and the preparation method thereof use waste aluminum materials as main raw materials, the utilization value of the waste aluminum is significantly improved through systematic raw material selection and crushing pretreatment, compared with primary aluminum production, more than 95% of energy consumption can be saved per ton of recycled aluminum alloy, and CO2 emission is reduced by more than 90%, so that remarkable energy-saving and emission-reducing benefits and low-carbon environmental protection advantages are achieved.

Description

Technical Field

[0001] This invention relates to the field of recycled aluminum alloy technology, specifically to a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy and its preparation method, which is particularly suitable for applications requiring high strength and corrosion resistance, such as building profiles, lightweight transportation components, and industrial structural parts. Background Technology

[0002] With the deepening implementation of the "dual-carbon" strategy, recycled aluminum alloys have attracted widespread attention due to their significant energy-saving and emission-reduction benefits—each ton of recycled aluminum can reduce carbon dioxide emissions by more than 90% compared to virgin aluminum. Recycling and remelting waste aluminum to produce recycled aluminum alloys is an important way to achieve green and circular development in the aluminum industry. Recycled aluminum alloys are already widely used in building profiles, automotive parts, and machinery manufacturing, and market demand continues to grow.

[0003] Existing recycled aluminum alloy preparation technologies have the following main shortcomings:

[0004] Firstly, impurity elements are difficult to control effectively. Impurity elements such as Fe, Cu, Zn, and Pb mixed in scrap aluminum cannot be effectively removed during the smelting process using conventional smelting and refining methods. Among them, iron is the most common and most harmful impurity. When the Fe content is too high, it will form needle-like β-AlFeSi phase, which severely ruptures the matrix and significantly reduces the alloy's plasticity, toughness, and corrosion resistance.

[0005] Secondly, the purity of the melt is insufficient. Traditional smelting and refining processes often use simple salt refining agents (such as NaCl-KCl mixed salt), which have limited refining effects. It is difficult to fully remove gases (hydrogen) and non-metallic inclusions in the melt, and the ingot is prone to casting defects such as porosity and pinholes, which affect the overall performance of the product.

[0006] Third, the grains are coarse and the microstructure is uneven. There is a lack of effective grain refinement and microstructure control methods in the smelting process of recycled aluminum alloys. The as-cast microstructure has coarse grains, and the uneven distribution of impurity elements leads to severe compositional segregation, resulting in unstable subsequent processing and service performance.

[0007] Fourth, traditional refining processes are environmentally unfriendly and inefficient. Chlorine- or fluorine-containing refining agents produce harmful gases (HCl, HF, etc.) at high temperatures, polluting the environment, corroding equipment, and requiring long refining times, resulting in low production efficiency.

[0008] Therefore, there is a need for a method for preparing recycled aluminum alloys that can effectively remove impurities, refine grains, improve melt purity, and is low-carbon and environmentally friendly, in order to solve the problems of difficult impurity control, insufficient melt purity, coarse grains, and poor environmental performance in existing technologies. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy and its preparation method. It has the advantages of being low-carbon and environmentally friendly, having high melt purity, fine grains, and high strength and corrosion resistance. It solves the problems of difficult-to-control impurities, insufficient purity, coarse grains, and poor environmental performance of traditional refining processes in existing recycled aluminum alloys.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] A method for preparing a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy includes the following steps:

[0012] S1. Raw material selection and crushing: The waste aluminum material is sorted to remove impurities and crushed to a particle size of ≤50mm. The ferromagnetic impurities and non-ferrous metal impurities are removed by magnetic separation and eddy current separation to obtain pre-treated waste aluminum material.

[0013] S2. Smelting: The pretreated waste aluminum material is put into a smelting furnace and heated to melt at 730℃~780℃. Intermediate alloy and pure magnesium ingots are added to adjust the composition to obtain an alloy melt.

[0014] S3. Refining: Inert gas is introduced into the alloy melt for rotary degassing and refining, while a composite refining agent is added for slag formation and impurity removal. After refining, the surface slag is removed to obtain a pure melt.

[0015] S4. Casting: Adjust the temperature of the pure melt to 680℃~720℃, add grain refiner and rare earth refiner, and cast into ingots using a semi-continuous casting method.

[0016] S5. Sawing: After homogenization, the ingot is sawn according to specifications.

[0017] Furthermore, in S1, the iron content in the sorted waste aluminum is controlled to be ≤1.0%, the copper content to be ≤0.5%, and the zinc content to be ≤0.5%.

[0018] Furthermore, in S3, the composite refining agent is composed of the following components by mass percentage: Na2SiF6 30%–50%, KCl 15%–30%, NaCl 10%–20%, Na2CO3 5%–15%, and calcium fluoride 5%–10%; the amount of the composite refining agent added is 0.2%–0.8% of the melt mass.

[0019] Furthermore, in step S3, the rotor speed for rotary degassing is 300–500 r / min, the inert gas flow rate is 1.0–2.5 m³ / h, and the refining time is 15–30 minutes; the inert gas is one or both of nitrogen and argon, with a purity of ≥99.99%.

[0020] Furthermore, in S4, the grain refiner is Al-Ti-B, and the addition amount is 0.1% to 0.3% of the melt mass; the rare earth refiner is cerium-based mixed rare earth, and the addition amount is 0.05% to 0.15% of the melt mass.

[0021] Furthermore, in step S5, the homogenization temperature is 540℃~570℃, and the holding time is 6~12 hours.

[0022] Furthermore, in S2, the alloy melt with adjusted composition contains, by mass percentage: Si: 0.40%–1.00%, Fe: 0.30%–0.80%, Cu: 0.10%–0.40%, Mn: 0.30%–0.80%, Mg: 0.60%–1.20%, Cr: 0.10%–0.30%, Zn: ≤0.25%, Ti: 0.01%–0.06%, B: 0.001%–0.005%, RE: 0.02%–0.15%, with the balance being Al and unavoidable impurities.

[0023] Furthermore, the mass ratio of Mn to Fe in the recycled aluminum alloy is controlled between 0.8 and 1.5, so that the acicular β-AlFeSi phase is transformed into granular or short rod-shaped α-AlFeSi phase.

[0024] Furthermore, in S4, the casting speed of the semi-continuous casting is 60-90 mm / min, and the casting temperature is 680℃-705℃.

[0025] This invention also provides a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy, comprising, by weight percentage:

[0026] Si: 0.40%–1.00%, Fe: 0.30%–0.80%, Cu: 0.10%–0.40%, Mn: 0.30%–0.80%, Mg: 0.60%–1.20%, Cr: 0.10%–0.30%, Zn: ≤0.25%, Ti: 0.01%–0.06%, B: 0.001%–0.005%, RE: 0.02%–0.15%, with the balance being Al and unavoidable impurities;

[0027] The recycled aluminum alloy has a tensile strength ≥300MPa, a yield strength ≥250MPa, an elongation ≥12%, and a salt spray corrosion weight loss rate ≤1.5%.

[0028] Compared with the prior art, the present invention provides a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy and its preparation method, which has the following beneficial effects:

[0029] 1. This high-strength, corrosion-resistant, low-carbon recycled aluminum alloy and its preparation method significantly improve the utilization value of waste aluminum by using scrap aluminum as the main raw material (recycled aluminum utilization rate ≥80%) and through systematic raw material sorting and crushing pretreatment. Compared with primary aluminum production, each ton of recycled aluminum alloy can save more than 95% of energy consumption and reduce CO2 emissions by more than 90%, demonstrating significant energy-saving and emission-reduction benefits and low-carbon environmental protection advantages.

[0030] 2. This high-strength, corrosion-resistant, low-carbon recycled aluminum alloy and its preparation method employ a refining process that combines rotary degassing with a composite refining agent. Rotary degassing uses a high-speed rotating rotor to shear inert gas into tiny bubbles, ensuring full contact with the melt and removing dissolved hydrogen and inclusions. The composite refining agent, containing Na₂SiF₆ and calcium fluoride, possesses strong slag-forming capabilities, efficiently adsorbing and removing non-metallic inclusions and harmful impurities from the melt. The synergistic effect significantly improves melt purity, achieving an ingot pinhole degree ≤2. The Al-Ti-B and RE composite refining process achieves a grain size of 6–9, far superior to the 3–5 of traditional recycled aluminum alloys.

[0031] 3. This high-strength, corrosion-resistant, low-carbon recycled aluminum alloy and its preparation method, through precise control of the Mn / Fe ratio (0.8–1.5), transforms the harmful acicular β-AlFeSi phase into granular or short rod-shaped α-AlFeSi phase, eliminating the brittle fracture effect on the matrix and improving the alloy's plasticity and corrosion resistance. Simultaneously, Cr promotes the formation of a dense oxide film on the surface, while RE rare earth elements purify grain boundaries and refine the microstructure. The synergistic effect of these three elements results in a tensile strength ≥300 MPa and a salt spray corrosion weight loss rate ≤1.5%, demonstrating significantly superior overall performance compared to similar recycled aluminum alloys. Attached Figure Description

[0032] Figure 1 This is a process flow diagram of a method for preparing a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy according to the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Please see Figure 1 .

[0035] Example 1:

[0036] S1: Raw material selection and crushing

[0037] Waste 6063 aluminum alloy profiles (reclaimed building materials) were selected as the main raw material and manually sorted to remove impurities such as steel parts, plastics, rubber, and oil. The sorted waste aluminum was then fed into a hammer crusher for further crushing until the particle size was ≤30mm. The crushed material was then passed through a suspended magnetic separator (magnetic field strength ≥8000Gs) to remove ferromagnetic impurities, and further processed by an eddy current separator to remove non-ferrous metal impurities such as copper and zinc. After pretreatment, the waste aluminum had an Fe content ≤0.8%, a Cu content ≤0.3%, and a Zn content ≤0.3%.

[0038] S2: Smelting

[0039] Pretreated aluminum scrap was fed into a 40-ton gas-fired melting furnace and heated to 760℃. After complete melting, samples were taken for spectral analysis. Based on the analysis results, Al-Si master alloy (20% Si content), Al-Mn master alloy (10% Mn content), Al-Cr master alloy (10% Cr content), and pure magnesium ingots were added to adjust the composition. The target composition was: Si 0.70%, Fe 0.50%, Cu 0.20%, Mn 0.55%, Mg 0.90%, Cr 0.20%, Zn ≤ 0.20%. After thorough stirring, the melt temperature was stabilized at 750℃.

[0040] S3: Refining

[0041] The melt was transferred to a refining furnace, and the rotary degassing device was started. Nitrogen (99.995% purity) was used as the refining gas, with a rotor speed of 400 r / min, a gas flow rate of 2.0 m³ / h, and a refining time of 20 minutes. A composite refining agent (0.5% of the melt mass) was added simultaneously during the refining process. The composition of the composite refining agent was: Na₂SiF₆ 40%, KCl 20%, NaCl 15%, Na₂CO₃ 15%, and calcium fluoride 10%. After refining, the surface scum was removed, and the mixture was allowed to stand for 10 minutes.

[0042] S4: Casting

[0043] The temperature of the refined pure melt was lowered to 700℃, and Al-Ti-B grain refiner (0.2%) and RE rare earth refiner (cerium-based mixed rare earth, 0.08%) were added. After stirring evenly, the mixture was allowed to stand for 15 minutes. Semi-continuous casting was then performed at a casting speed of 80 mm / min, a casting temperature of 695℃, and a cooling water pressure of 0.3 MPa, yielding a round ingot with a diameter of 152 mm.

[0044] S5: Sawing

[0045] The cast ingots were homogenized at 560℃ and held for 8 hours, then cooled in the furnace to 150℃ before being air-cooled. The homogenized ingots were then sawn into short ingots of 600mm in length according to specifications.

[0046] Product performance testing:

[0047] Chemical composition (measured): Si 0.72%, Fe 0.48%, Cu 0.18%, Mn 0.58%, Mg 0.92%, Cr 0.19%, Zn 0.18%, Ti 0.03%, B 0.003%, RE 0.07%, balance Al;

[0048] Tensile strength: 325 MPa;

[0049] Yield strength: 268 MPa;

[0050] Elongation: 14.5%;

[0051] Grain size: Grade 8.0;

[0052] Salt spray corrosion weight loss rate (72h neutral salt spray): 1.2%;

[0053] Mn / Fe ratio: 1.21.

[0054] Example 2:

[0055] S1: Raw material selection and crushing

[0056] Waste 6005A aluminum alloy profiles were selected as the main raw material and sorted, crushed, and magnetically separated according to the method in Example 1. The pretreated waste aluminum had an Fe content ≤0.7%, a Cu content ≤0.2%, and a Zn content ≤0.2%.

[0057] S2: Smelting

[0058] The mixture was heated to 740℃ and the target composition was adjusted as follows: Si 0.50%, Fe 0.35%, Cu 0.15%, Mn 0.45%, Mg 0.75%, Cr 0.15%, Zn≤0.15%. The melt temperature was stabilized at 745℃.

[0059] S3: Refining

[0060] Argon gas (99.999% purity) was used for rotary degassing at a rotor speed of 350 r / min and a gas flow rate of 1.5 m³ / h for 25 minutes. The amount of composite refining agent added was 0.4% of the melt mass.

[0061] S4: Casting

[0062] The melt temperature was reduced to 690℃, the Al-Ti-B addition was 0.15%, the RE rare earth refining agent addition was 0.06%, and the mixture was allowed to stand for 12 minutes. The semi-continuous casting speed was 70 mm / min, and the casting temperature was 685℃.

[0063] S5: Sawing

[0064] Homogenization temperature 550℃, holding time 10 hours, sawn into short ingots 800mm in length.

[0065] Product performance testing:

[0066] Tensile strength: 312 MPa;

[0067] Yield strength: 258 MPa;

[0068] Elongation: 15.2%;

[0069] Grain size: Grade 7.5;

[0070] Salt spray corrosion weight loss rate: 1.1%.

[0071] Example 3:

[0072] S1: Raw material selection and crushing

[0073] Mixed scrap aluminum profiles (6063 / 6005A mixture) were selected as the main raw material and pretreated according to the method in Example 1. After pretreatment, the Fe content, Cu content, and Zn content of the scrap aluminum were ≤1.0%, ≤0.4%, and ≤0.4%, respectively.

[0074] S2: Smelting

[0075] The mixture was heated to 770℃ and the target composition was adjusted as follows: Si 0.90%, Fe 0.70%, Cu 0.30%, Mn 0.75%, Mg 1.10%, Cr 0.25%, Zn≤0.20%. The melt temperature was stabilized at 755℃.

[0076] S3: Refining

[0077] Nitrogen rotary degassing was performed at a rotor speed of 450 r / min, a gas flow rate of 2.2 m³ / h, and a refining time of 18 minutes. The amount of composite refining agent added was 0.6% of the melt mass.

[0078] S4: Casting

[0079] The melt temperature was reduced to 705℃, the Al-Ti-B addition was 0.25%, the RE rare earth refining agent addition was 0.12%, and the mixture was allowed to stand for 18 minutes. The semi-continuous casting speed was 90 mm / min, and the casting temperature was 700℃.

[0080] S5: Sawing

[0081] Homogenization temperature 565℃, holding time 6 hours, sawn into short ingots 700mm in length.

[0082] Product performance testing:

[0083] Tensile strength: 338 MPa;

[0084] Yield strength: 282 MPa;

[0085] Elongation: 12.8%;

[0086] Grain size: Grade 8.5;

[0087] Salt spray corrosion weight loss rate: 1.4%.

[0088] Example 4: Effect of different Mn / Fe ratios on alloy properties

[0089] Following the preparation method of Example 1, alloy samples with different Mn / Fe ratios were prepared by adjusting the amount of Mn added. The effect of different Mn / Fe ratios on the alloy properties is shown in Table 1.

[0090] Table 1

[0091] Sample Mn / Fe ratio Tensile strength / MPa elongation Salt spray corrosion weight loss rate Fe phase morphology A 0.5 285 10.2% 2.8% Needle-like (β phase) B 0.8 308 13.5% 1.6% Short rod-shaped / granular C 1.2 325 14.5% 1.2% Granular (α phase) D 1.8 318 2.0% 1.8% Granular (coarse)

[0092] The results show that when the Mn / Fe ratio is in the range of 0.8 to 1.5, the harmful needle-like β-AlFeSi phase is transformed into granular or short rod-like α-AlFeSi phase, and the alloy has the best comprehensive performance.

[0093] Comparative Example 1: Recycled aluminum alloy without added Mn / Cr

[0094] The preparation method of Example 1 was followed, but without adding Al-Mn master alloy and Al-Cr master alloy (Mn and Cr contents were not adjusted), and the remaining steps were the same.

[0095] Performance testing:

[0096] Tensile strength: 265 MPa;

[0097] Elongation: 8.5%;

[0098] Salt spray corrosion weight loss rate: 3.2%;

[0099] Fe phase morphology: needle-like β-AlFeSi phase (SEM observation shows it as long needle-like, with a length of 50-100 μm).

[0100] Comparative conclusion: In the alloy without added Mn / Cr, the acicular β-AlFeSi phase severely disrupts the matrix, resulting in a significant decrease in strength and elongation, and a deterioration in corrosion resistance.

[0101] Comparative Example 2: Traditional salt refining (without rotary degassing)

[0102] The preparation method is the same as in Example 1, but conventional salt refining is used (only NaCl-KCl mixed salt is added, and rotary degassing is not performed), and the rest of the steps are the same.

[0103] Performance testing:

[0104] Ingot pinholes: Grade 3 (obvious porosity and pinholes exist);

[0105] Tensile strength: 278 MPa;

[0106] Elongation: 9.8%;

[0107] Salt spray corrosion weight loss rate: 2.5%.

[0108] Comparative conclusion: Traditional salt refining cannot effectively remove gases and inclusions from the melt, resulting in low ingot density and significantly lower overall performance than this invention.

[0109] Comparative Example 3: No Al-Ti-B and RE refining agent added

[0110] The preparation method of Example 1 is followed, but without adding Al-Ti-B grain refiner and RE rare earth refiner; the remaining steps are the same.

[0111] Performance testing:

[0112] Grain size: Grade 4.5 (coarse grains);

[0113] Tensile strength: 290 MPa;

[0114] Elongation: 10.5%.

[0115] Comparative conclusion: Recycled aluminum alloys lacking grain refinement treatment have coarse grains, and their strength and elongation are significantly reduced.

[0116] Example 5: Industrialized Continuous Production Verification

[0117] The method of this invention was used to conduct five consecutive industrial-scale production verifications (40 tons per furnace) at a recycled aluminum enterprise. The statistical results are as follows:

[0118] Average recovery rate: 92.5%;

[0119] Product qualification rate: 98.2%;

[0120] Energy consumption per ton of product: ≤130kg of standard coal;

[0121] CO2 emissions: ≤0.5 tons / ton of product (approximately 92% reduction compared to primary aluminum);

[0122] The mechanical property fluctuation of the products from 5 heats: the range of tensile strength difference is ≤15MPa, indicating that the process of the present invention has good stability and strong batch-to-batch consistency.

[0123] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0124] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy, characterized in that, Includes the following steps: S1. Raw material selection and crushing: The waste aluminum material is sorted to remove impurities and crushed to a particle size of ≤50mm. The ferromagnetic impurities and non-ferrous metal impurities are removed by magnetic separation and eddy current separation to obtain pre-treated waste aluminum material. S2. Smelting: The pretreated waste aluminum material is put into a smelting furnace and heated to melt at 730℃~780℃. Intermediate alloy and pure magnesium ingots are added to adjust the composition to obtain an alloy melt. S3. Refining: Inert gas is introduced into the alloy melt for rotary degassing and refining, while a composite refining agent is added for slag formation and impurity removal. After refining, the surface slag is removed to obtain a pure melt. S4. Casting: Adjust the temperature of the pure melt to 680℃~720℃, add grain refiner and rare earth refiner, and cast into ingots using a semi-continuous casting method. S5. Sawing: After homogenization, the ingot is sawn according to specifications.

2. The method for preparing a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy according to claim 1, characterized in that, In step S1, the iron content, copper content, and zinc content in the sorted waste aluminum are controlled to be ≤1.0%, ≤0.5%, and ≤0.5%, respectively.

3. The method for preparing a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy according to claim 1, characterized in that, In S3, the composite refining agent is composed of the following components by mass percentage: Na2SiF6 30%–50%, KCl 15%–30%, NaCl 10%–20%, Na2CO3 5%–15%, and calcium fluoride 5%–10%; the amount of the composite refining agent added is 0.2%–0.8% of the melt mass.

4. The method for preparing a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy according to claim 1, characterized in that, In step S3, the rotor speed for rotary degassing is 300–500 r / min, the inert gas flow rate is 1.0–2.5 m³ / h, and the refining time is 15–30 minutes; the inert gas is one or both of nitrogen and argon, with a purity of ≥99.99%.

5. The method for preparing a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy according to claim 1, characterized in that, In S4, the grain refiner is Al-Ti-B, and the addition amount is 0.1% to 0.3% of the melt mass; the rare earth refiner is cerium-based mixed rare earth, and the addition amount is 0.05% to 0.15% of the melt mass.

6. The method for preparing a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy according to claim 1, characterized in that, In step S5, the homogenization temperature is 540℃~570℃, and the holding time is 6~12 hours.

7. The method for preparing a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy according to claim 1, characterized in that, In S2, the alloy melt with adjusted composition contains, by mass percentage: Si: 0.40%–1.00%, Fe: 0.30%–0.80%, Cu: 0.10%–0.40%, Mn: 0.30%–0.80%, Mg: 0.60%–1.20%, Cr: 0.10%–0.30%, Zn: ≤0.25%, Ti: 0.01%–0.06%, B: 0.001%–0.005%, RE: 0.02%–0.15%, with the balance being Al and unavoidable impurities.

8. The method for preparing a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy according to claim 1, characterized in that, The mass ratio of Mn to Fe in the recycled aluminum alloy is controlled between 0.8 and 1.5, so that the acicular β-AlFeSi phase is transformed into granular or short rod-shaped α-AlFeSi phase.

9. The method for preparing a high-strength, corrosion-resistant, low-carbon recycled aluminum alloy according to claim 1, characterized in that, In S4, the casting speed of the semi-continuous casting is 60-90 mm / min, and the casting temperature is 680℃-705℃.

10. A high-strength, corrosion-resistant, low-carbon recycled aluminum alloy prepared by the method according to any one of claims 1-9, characterized in that, Included by weight percentage: Si: 0.40%–1.00%, Fe: 0.30%–0.80%, Cu: 0.10%–0.40%, Mn: 0.30%–0.80%, Mg: 0.60%–1.20%, Cr: 0.10%–0.30%, Zn: ≤0.25%, Ti: 0.01%–0.06%, B: 0.001%–0.005%, RE: 0.02%–0.15%, with the balance being Al and unavoidable impurities; The recycled aluminum alloy has a tensile strength ≥300MPa, a yield strength ≥250MPa, an elongation ≥12%, and a salt spray corrosion weight loss rate ≤1.5%.

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