Method for producing super-thin corrosion-resistant air conditioner heat dissipation hydrophilic foil from magnesium-aluminum alloy scrap

Abstract

The present application belongs to the technical field of aluminum alloy production, and specifically discloses a method for producing an ultra-thin corrosion-resistant air conditioner heat-dissipating hydrophilic foil from magnesium-containing aluminum alloy waste, which utilizes magnesium-containing aluminum alloy can waste to produce an aluminum foil with a thickness of 0.075-0.08 mm through continuous casting and rolling, fully meets the punching use effect, realizes stable production of the ultra-thin corrosion-resistant air conditioner heat-dissipating hydrophilic aluminum foil, adapts to the use requirements of high-end air conditioner heat-dissipating components, and reduces the thickness of the aluminum foil by 18.42% compared with the current conventional thickness, which can reduce the annual material consumption by 184200 tons, has a remarkable cost reduction effect, and has obvious economic benefits. Meanwhile, the method realizes efficient recycling of waste cans, solves the problems of narrow digestion direction of aluminum alloy waste cans, and multiple inclusions and easy breaking during rolling of the production blank.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy production technology, and specifically discloses a method for producing ultra-thin corrosion-resistant hydrophilic foil for air conditioning heat dissipation using magnesium-containing aluminum alloy waste. Background Technology

[0002] Currently, hydrophilic aluminum foil for air conditioning heat dissipation is commonly produced using 3102 alloy. Because the annealing of 3102 alloy is a stress-relief annealing process, the thinner the finished product, the higher the internal energy of the grains. Annealing crystallization is highly likely to occur during annealing, severely impacting the performance of the finished product and leading to material scrap. For example, producing thinner products can easily result in punching cracks and pore formation. Furthermore, the low Mn content of 3102 alloy leads to weak corrosion resistance, making the aluminum foil cross-section prone to corrosion in highly corrosive environments. This fails to meet the lightweight, long-life, and high-reliability requirements of high-end heat exchangers. As refrigeration and thermal management equipment upgrades to meet the demands for ultra-thin, lightweight, and corrosion-resistant materials, the market places higher demands on the thickness, corrosion resistance, and mechanical stability of hydrophilic aluminum foil. The application demand for ultra-thin hydrophilic aluminum foil (0.075–0.08 mm) is surging year by year. Producing ultra-thin, highly corrosion-resistant hydrophilic foil using existing 3102 alloy presents significant technical challenges.

[0003] China consumes a huge amount of aluminum alloy beverage cans, and in recent years, the end-user recycling channels have improved, with the recycling rate gradually increasing. However, due to the presence of manganese and magnesium in the can material, its subsequent uses are limited. Furthermore, the coating and printing on the can surface may result in excessive levels of heavy metals. These waste materials are thus restricted in their utilization, failing to achieve the goal of recycling can waste for can manufacturing.

[0004] 3005 aluminum alloy belongs to the aluminum-manganese-magnesium (AMA) series of rust-resistant aluminum alloys. It has a high manganese content, moderate magnesium content, and also contains elements such as iron and silicon. Its production process is relatively simple, and the finished product has higher strength than 3102, exhibiting significant advantages in resistance to corrosion in conventional environments. Using 3005 alloy to produce ultra-thin corrosion-resistant hydrophilic foil would allow for the use of aluminum alloy scrap from aluminum cans, combining advantages in main material cost, production, quality, and cost reduction through thinning. Furthermore, the annual recycling volume of aluminum alloy scrap from aluminum cans exceeds 1 million tons, while the annual demand for hydrophilic foil is approximately 1.1 million tons, indicating a potential supply-demand match. Summary of the Invention

[0005] To address the problems in the background art, this invention discloses a method for producing ultra-thin, corrosion-resistant, hydrophilic aluminum foil for air conditioning heat dissipation using magnesium-aluminum alloy waste. This method enables stable production of ultra-thin, corrosion-resistant hydrophilic aluminum foil for air conditioning heat dissipation, meeting the needs of high-end air conditioning heat dissipation components. Simultaneously, it achieves efficient recycling and reuse of waste aluminum cans, solving the problems of narrow utilization of aluminum alloy waste from aluminum cans, excessive inclusions in production blanks, and easy breakage during rolling.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: The method for producing ultra-thin, corrosion-resistant, hydrophilic heat dissipation foil for air conditioners using magnesium-aluminum alloy waste includes the following steps: S1. Smelting: 50%–60% (by mass percentage) of recycled aluminum scrap from aluminum cans and 40%–50% of molten electrolytic aluminum are sequentially added to the smelting furnace and heated and remelted to prepare an aluminum melt. The melt is sampled and tested for alloy composition. Based on the test results, quick-dissolving silicon, iron, copper, manganese, magnesium ingots, and titanium are added to the smelting furnace under stirring. After uniform stirring, the melt is sampled again for testing to ensure the alloy composition is adjusted to meet standards. The mass percentages of each component are: Si: 0.2–0.4%, Fe: 0.5–0.7%, Cu: ≤0.1%, Mn: 1.0–1.2%, Mg: 0.2–0.4%, Cr: ≤0.1%, Zn: ≤0.1%. ≤0.1%, Ti: 0.01~0.04%, other individual impurities ≤0.03%, total ≤0.15%, balance is Al. Refining is carried out using high-purity argon + granular refining agent. Each refining session lasts 20~30 minutes. After multiple refining sessions, slag is removed. After slag removal, the furnace is allowed to stand for 20~30 minutes before starting. After starting, the melt flows steadily into the guide channel. Four sets of aluminum-titanium-boron wires are added to the melt at a uniform speed. 1.5-2.0 kg of aluminum-titanium-boron wires are added per ton of aluminum melt. The melt flows into the degassing box through the guide channel for online degassing. Granular refining agent is introduced into the degassing box. After refining, the melt is filtered online through a four-stage plate filter box and then enters the front box through a vertical flow stabilizer. S2, Continuous casting: The temperature of the melt in the front box is 672~682℃. The melt in the front box flows into the casting cavity of the casting machine through the casting nozzle. The melt solidifies in the casting cavity to form a billet. The billet is discharged from the plate as the upper and lower steel strips rotate in the same direction. The casting speed is 8.5~9.2m / min and the billet thickness is 19mm. S3. Continuous rolling: The slab obtained in step S2 is fed into a three-stand rolling mill for rolling. The slab exit thickness of the first stand of the three-stand rolling mill is 9.0-10.0 mm, the slab exit thickness of the second stand of the three-stand rolling mill is 4.5-5.5 mm, and the slab exit thickness of the third stand of the three-stand rolling mill is 2.5-3.0 mm. The slab exiting the third stand of the three-stand rolling mill is coiled into a coil. S4. Intermediate Annealing: The billet coil obtained in step S3 is suspended in a nitrogen-protected annealing furnace for annealing. Before annealing, the aluminum coil is perforated and the temperature is measured. The annealing process is set according to the measured temperature of the aluminum coil. The specific annealing process is as follows: the furnace temperature is raised to 500-550℃ at a uniform rate for two hours. After the metal temperature rises to 400-450℃, it is held at that temperature for 6 hours. Then the furnace temperature is lowered to 150-200℃ and the coil is taken out of the furnace and allowed to cool naturally to room temperature. S5, Cold Foil Rolling: The aluminum coils that have been annealed in the intermediate furnace are cooled to below 45°C and directly rolled on the cold rolling mill. After 6 passes, a base material with a thickness of 0.2mm is obtained. The base material is then transferred to a slitting machine for edge trimming. The trimmed cold-rolled coils are then transferred to an aluminum foil rolling mill for rolling. After 2 passes, an aluminum foil coil with a thickness of 0.075 to 0.08mm is obtained. S6. Finished product annealing: Place the 0.075-0.08mm aluminum foil roll obtained in step S5 into the annealing furnace for finished product annealing. After two hours of uniform heating to 200-250℃ and holding under negative pressure for 3-6 hours, slowly heat up to 280-350℃ for two hours and hold under positive pressure for 35-45 hours. Finally, reduce the furnace temperature to 170℃ and remove from the furnace, and allow it to cool naturally to room temperature. S7. Coating: The finished annealed and cooled aluminum foil roll is coated on both sides by a coating machine at a speed of 120m / min. The aluminum foil, which has been cleaned, coated with a base coat and a top coat in sequence, is stretched and rolled up and wound into a roll by a winding device to obtain a corrosion-resistant hydrophilic aluminum roll with uniform color and good shape. S8. Slitting: Transfer the coated product from step S7 to a single-cutting machine for edge trimming. Trim 6mm on both sides. The slitting product should have less than 0.5mm of misaligned layers and tower-shaped defects. The slitting speed is 200-250m / min. Perform online material inspection during slitting to ensure that the upper and lower surfaces of the slitting product are free of coating defects and color differences. S9. Quality Inspection: Take a small sample of the finished aluminum foil for testing. The tensile strength of the finished aluminum foil is 135MPa~145MPa, the elongation is ≥21%, and the cupping is ≥6.3mm. The initial hydrophilic angle of the coating of the finished product is ≤10°. After 2000h salt spray test, the aluminum foil has no perforations. After passing the inspection, it is packaged according to the packaging requirements.

[0007] Furthermore, in the production of ultra-thin, corrosion-resistant, hydrophilic aluminum foil for air conditioning heat dissipation from aluminum alloy waste from beverage cans, in step S1, the melt temperature during melting in the smelting furnace is 765℃~775℃, and after the alloy composition is adjusted to meet the requirements, the melt temperature is maintained at 725℃~735℃.

[0008] Furthermore, in the production of ultra-thin, corrosion-resistant, hydrophilic aluminum foil for air conditioning heat dissipation from aluminum alloy waste from beverage cans, in step S1, 1 to 1.5 kg of granular refining agent is used per ton of aluminum during refining in the smelting furnace, and 0.2 to 0.5 kg of granular refining agent is used per ton of aluminum during refining in the degassing box.

[0009] Furthermore, in the production of ultra-thin, corrosion-resistant, hydrophilic aluminum foil for air conditioning heat dissipation from aluminum alloy scrap from beverage cans, in step S2, graphite emulsion is sprayed onto the steel strip at the billet exit position. The ratio of water to graphite emulsion in the graphite emulsion is 20:1 to 30:1, and the spraying rate of the graphite emulsion is 40 to 80 ml / min. After the graphite is sprayed, an electromagnetic induction device is used to heat the steel strip, and the temperature of the steel strip is controlled at 90 to 110°C.

[0010] Furthermore, in the production of ultra-thin, corrosion-resistant, hydrophilic aluminum foil for air conditioning heat dissipation from aluminum alloy scrap from beverage cans, in step S3, after the billet is rolled off the mill in three consecutive rolling mills, a vacuum cleaner is used to remove residual emulsion from the end face of the billet to ensure that no residual emulsion drips from the end face.

[0011] Furthermore, in the production of ultra-thin, corrosion-resistant, hydrophilic aluminum foil for air conditioning heat dissipation from aluminum alloy scrap from beverage cans, in step S4, the nitrogen concentration in the nitrogen furnace during intermediate annealing is ≥99.85%.

[0012] Furthermore, in the production of ultra-thin, corrosion-resistant, hydrophilic aluminum foil for air conditioning heat dissipation from aluminum alloy waste from beverage cans, in step S5, during cold rolling and foil rolling, the roughness of the rolls in the cold rolling mill is 0.35–0.45 μm, and the roughness of the rolls in the foil rolling mill is 0.25–0.35 μm. During cold rolling, each roll of material is rolled no more than twice by the same set of rolls in the cold rolling mill, and during foil rolling, each roll of material is rolled no more than once by the same set of rolls in the foil rolling mill.

[0013] Furthermore, in the production of ultra-thin, corrosion-resistant hydrophilic aluminum foil for air conditioning heat dissipation from aluminum alloy scrap from beverage cans, in step S6, during the annealing of the finished product, the relative humidity of the air inside the annealing furnace is ≤4%RH.

[0014] Furthermore, in the production of ultra-thin, corrosion-resistant, hydrophilic aluminum foil for air conditioning heat dissipation from aluminum alloy waste from beverage cans, during step S7 coating, the aluminum foil is first degreased in a degreasing tank to remove surface grease, then rinsed clean with water in a washing tank, and then squeezed dry with a squeezing roller. After drying in an oven at a temperature controlled at 400-550℃, it is coated with primer on both sides by a base coat roller, and the primer coating is dried in an oven at a metal plate temperature of 210-250℃. Finally, the topcoat is coated on both sides by a top coat roller, and the topcoat coating is dried in an oven at a metal plate temperature of 215-255℃.

[0015] Furthermore, in the production of ultra-thin, corrosion-resistant, hydrophilic aluminum foil for air conditioning heat dissipation from aluminum alloy waste from beverage cans, in step S7, the weight of the single-layer base coating corrosion-resistant layer is 0.6-0.8 g / m², and the weight of the single-layer top coating hydrophilic layer is 0.2-0.3 g / m².

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention relates to a method for producing ultra-thin, corrosion-resistant, hydrophilic aluminum foil for air conditioning heat dissipation using magnesium-containing aluminum alloy waste. The method utilizes magnesium-containing aluminum alloy waste from aluminum cans. While this type of waste is widely available, its application is limited due to its high magnesium and manganese content. Producing high-manganese and high-magnesium alloys requires hot rolling, which is inherently costly. Furthermore, the high deformation resistance of the high-alloy-element billet necessitates additional rolling passes, further increasing production costs. Additionally, the melting of the coating from this type of waste reveals heavy metals such as lead, chromium, and nickel, limiting the finished product's applications. However, hydrophilic aluminum foil for air conditioning only needs to meet heat transfer and dissipation requirements, without needing to meet the strict restrictions on heavy metal content in food and pharmaceutical packaging materials. Moreover, the surface of the hydrophilic aluminum foil contains an anti-corrosion coating, and the corrosion performance deviation caused by chromium, zinc, and other elements in the alloy can be completely compensated for by the anti-corrosion effect of the coating itself, without affecting the material. 2. This invention relates to a method for producing ultra-thin, corrosion-resistant, hydrophilic foil for air conditioning heat dissipation using magnesium-aluminum alloy waste. The annual consumption of hydrophilic aluminum foil exceeds 1 million tons. Currently, the conventional thickness is 0.095 mm, while this method produces aluminum foil with a thickness of only 0.075–0.08 mm, which fully meets the requirements for stamping and use. The thinned aluminum foil is 18.42% thinner than the current conventional thickness. It is estimated that the annual consumption can be reduced by 184,200 tons of material, resulting in significant cost reduction and obvious economic benefits. 3. The present invention provides a method for producing ultra-thin corrosion-resistant hydrophilic foil for air conditioning heat dissipation using magnesium-aluminum alloy waste. The finished product is in the 3005H22 state, which is in an incomplete crystallization annealing state. Compared with the existing technology of 3102 aluminum alloy in the H26 stress-relief annealing state, the performance is more stable and can avoid quality problems caused by fluctuations in the performance of the finished product. 4. The present invention relates to a method for producing ultra-thin, corrosion-resistant, hydrophilic heat dissipation foil for air conditioners using magnesium-aluminum alloy waste. This method utilizes 3005 alloy, which is predominantly manganese with magnesium as a secondary element, readily forming Al6Mn / Al 12 Mn and other dispersed phases reduce grain boundary precipitation by refining grains, hindering corrosion channels and providing excellent corrosion protection. In addition, a dense and stable Al-Mn composite oxide film is formed on the surface, which improves the density and adhesion of the oxide film, isolates water / oxygen / chloride ions, is not easy to perforate, and greatly improves the service life of the product. It is more resistant to corrosion in humid / marine environments, while also increasing strength and reducing deformation-induced microcrack corrosion. 5. The present invention provides a method for producing ultra-thin anti-corrosion hydrophilic foil for air conditioning using magnesium-aluminum alloy waste. The aluminum foil material itself has a significant improvement effect on corrosion resistance. During the coating production, the production process can be optimized, reducing the weight of the primer corrosion-resistant layer to 0.6-0.8 g / m². The conventional primer corrosion-resistant layer weight is 0.8-1.2 g / m². The reduction in film weight reduces the production cost of the primer coating process by about 30%. 6. The present invention provides a method for producing ultra-thin corrosion-resistant hydrophilic foil for air conditioning using magnesium-aluminum alloy waste. In the smelting process, a high melt temperature is maintained during melting to promote Mg oxidation and reduce Mg content, which facilitates the control of alloy composition. During melt holding, a low melt temperature is controlled to avoid Mg oxidation and slag formation. The process is supplemented by a melt treatment process of three consecutive refining steps, slag removal, and settling to achieve precise control of Mg content, achieve the purification goal of high melt quality, and ensure the stable quality of the final aluminum foil product. 7. This invention relates to a method for producing ultra-thin, corrosion-resistant, hydrophilic heat dissipation foil for air conditioners using magnesium-aluminum alloy waste. The intermediate annealing is protected by nitrogen to isolate oxygen and prevent high-temperature oxidation of Mn and Mg elements in 3005. After annealing, the strip does not turn yellow, black, or have white spots, and the surface oxide film is thin and uniform. The finished product annealing uses a low-humidity positive pressure atmosphere to prevent corrosion of the aluminum foil with water vapor in the air at high temperatures and to prevent oxidation of Mg elements precipitated at grain boundaries, which would cause white spots. The combination of nitrogen-protected intermediate annealing and low-humidity positive pressure finished product annealing can greatly improve the surface quality of the aluminum foil and eliminate quality problems such as color difference and white spots on the aluminum foil surface. Detailed Implementation

[0017] The present invention will be further explained and illustrated below with reference to embodiments. However, this should not be construed as limiting the scope of protection of the present invention. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention.

[0018] Example 1 The method for producing ultra-thin, corrosion-resistant, hydrophilic heat dissipation foil for air conditioners using magnesium-aluminum alloy waste includes the following steps: S1. Smelting: 52.5% (by mass percentage) of recycled aluminum scrap from aluminum cans and 47.5% (by mass percentage) of molten electrolytic aluminum are sequentially added to the smelting furnace and heated and remelted to prepare an aluminum melt at a temperature of 772℃. The melt is sampled and tested for alloy composition. Based on the test results, quick-dissolving silicon, iron, copper, manganese, magnesium ingots, and titanium are added to the smelting furnace under stirring. After thorough mixing, the melt is sampled again to ensure the alloy composition is properly adjusted. The mass percentages of each component are: Si: 0.24%, Fe: 0.59%, Cu: 0.05%, Mn: 1.12%, Mg: 0.29%, Cr: 0.02%, Zn: 0.03%, Ti: 0.02%, and other individual impurities ≤0.03%, total ≤0.15%. The remainder is Al. After the melt composition is adjusted to meet the requirements, the melt temperature is reduced to 732℃. High-purity argon and granular refining agent are used for refining. Each refining process takes 28 minutes. 1.5 kg of granular refining agent is used per ton of aluminum during refining. After three consecutive refining processes, slag is removed. After slag removal, the melt is allowed to stand for 30 minutes before the furnace is started. After the furnace is started, the melt flows smoothly into the guide channel. Four sets of aluminum-titanium-boron wires are added to the melt at a uniform speed. 1.6 kg of aluminum-titanium-boron wires are added per ton of aluminum melt. The melt flows into the SNIIF degassing box through the guide channel for online degassing. Granular refining agent is introduced into the degassing box. 0.3 kg of granular refining agent is used per ton of aluminum. The refined melt is filtered online through a two-stage plate filter box with filter plates of 30+30 mesh and 40+50 mesh, respectively. Then it enters the front box through a vertical flow stabilizer. S2, Continuous Casting: The melt temperature in the forebox is 678℃. The melt in the forebox flows into the casting cavity of the casting machine through the casting nozzle. The melt solidifies in the casting cavity to form a billet. The billet exits the plate as the upper and lower steel strips rotate in the same direction. The casting speed is 9.1m / min, and the billet thickness is 19mm. Graphite emulsion is sprayed onto the steel strip at the billet exit position. The ratio of water to graphite emulsion in the graphite emulsion is 22:1, and the graphite emulsion spraying volume is 75ml / min. After graphite spraying, an electromagnetic induction device is used to heat the steel strip, and the steel strip temperature is 98℃. S3. Continuous rolling: The billet obtained in step S2 is fed into a three-stand continuous rolling mill for rolling. The billet exit thickness of the first stand of the three-stand continuous rolling mill is 9.5 mm, the billet exit thickness of the second stand of the three-stand continuous rolling mill is 4.9 mm, and the billet exit thickness of the third stand of the three-stand continuous rolling mill is 2.7 mm. After the billet exits the three-stand continuous rolling mill, the residual emulsion on the end face of the billet is removed by a vacuum cleaner to ensure that there is no residual emulsion dripping from the end face. The billet exiting the third stand of the three-stand continuous rolling mill is coiled into a coil. A 605 sleeve is built into the billet coil to facilitate suspended annealing. S4. Intermediate Annealing: The billet coil obtained in step S3 is suspended in a nitrogen-protected annealing furnace for annealing. The nitrogen concentration is 99.85%. During annealing, the aluminum coil is punched and the temperature is measured. The annealing process is set according to the measured aluminum coil temperature. The annealing process is as follows: the furnace temperature is raised to 530°C after two hours, and the metal temperature is held at 430°C for 6 hours. Finally, the furnace temperature is lowered to 170°C and the coil is taken out of the furnace and allowed to cool naturally to room temperature. S5. Cold and Foil Rolling: The aluminum coils that have been annealed in the intermediate furnace are cooled to 43°C and directly rolled on the cold rolling mill. The cold rolling mill rolls have a roughness of 0.38µm. After 6 passes, a base material with a thickness of 0.2mm is obtained. The base material is then transferred to a slitting machine for edge trimming. The trimmed cold-rolled coils are then transferred to an aluminum foil rolling mill for rolling. The foil rolling mill rolls have a roughness of 0.25µm. After 2 passes, an aluminum foil coil with a thickness of 0.075mm is obtained. During cold rolling, each coil is rolled twice on the same set of rolls in the cold rolling mill. During foil rolling, each coil is rolled once on the same set of rolls in the foil rolling mill. S6. Finished product annealing: The 0.075mm aluminum foil roll obtained in step S5 is placed in an annealing furnace for finished product annealing. The relative humidity of the air in the annealing furnace is 3%RH. After two hours of uniform heating to 220℃, and holding under negative pressure for 4 hours, the temperature is slowly increased to 295℃ for two hours, and held under positive pressure for 42 hours. Finally, the furnace temperature is reduced to 170℃ and the product is taken out of the furnace and allowed to cool naturally to room temperature. S7. Coating: The finished annealed and cooled aluminum foil rolls are coated on both sides using a coating machine at a speed of 120m / min. The aluminum foil is first degreased in a degreasing tank to remove surface grease, then rinsed with clean water in a washing tank, and then squeezed dry with a squeezing roller. After drying in a small oven at a temperature controlled at 480℃, it is coated with primer on both sides by a base coat roller and dried in a large oven at a metal plate temperature of 230℃. The weight of a single layer of corrosion-resistant base coat is 0.69g / ㎡. Finally, the topcoat is coated on both sides by a top coat roller and dried in a large oven at a metal plate temperature of 235℃. The weight of a single layer of hydrophilic topcoat is 0.25g / ㎡. The cleaned, base-coated, and top-coated aluminum foil is stretched and wound into a roll by a winding device to obtain a corrosion-resistant hydrophilic aluminum roll with uniform color and good shape. S8. Slitting: Transfer the coated product from step S7 to a single-cutting machine to trim the edges. Trim approximately 6mm from each side. The slitting product should have a roll-off error and a tower shape of less than 0.5mm. The slitting speed is 220m / min. During slitting, perform online inspection of the material. The upper and lower surfaces of the slitting product should be free of uncoated areas and color differences. S9. Quality Inspection: Take a small sample of the finished aluminum foil for testing. The tensile strength of the finished aluminum foil is 142MPa, the elongation is 23%, and the cupping is 6.5mm. The initial hydrophilicity angle of the coating is 9.2°. After 2000h salt spray test, there are no perforations in the aluminum foil. After passing the inspection, it is packaged according to the packaging requirements.

[0019] Salt spray corrosion resistance test procedure: Take a 150×150mm sample and place it in the salt spray chamber at a 15-25° angle to the vertical. Set the salt spray chamber temperature to 35±2℃ and the saturator temperature to 47℃. Use a 5% sodium chloride solution (by mass percentage) prepared with chemically pure or analytically pure sodium chloride and deionized water as the corrosive medium. Set the salt spray deposition rate in the salt spray chamber to be [value missing] per 80cm. 2 The salt spray deposition rate is 1.0 mL to 2.0 mL per hour on a horizontal surface. After running the salt spray test chamber for 2000 hours, the sample is taken out to check whether the aluminum foil is punctured.

[0020] Example 2 The method for producing ultra-thin, corrosion-resistant, hydrophilic heat dissipation foil for air conditioners using magnesium-aluminum alloy waste includes the following steps: S1. Smelting: 58.3% (by mass percentage) of recycled aluminum scrap from aluminum cans and 41.7% (by mass percentage) of molten electrolytic aluminum are sequentially added to the smelting furnace and heated and remelted to prepare an aluminum melt at a temperature of 768℃. The melt is sampled and tested for alloy composition. Based on the test results, quick-dissolving silicon, iron, copper, manganese, magnesium ingots, and titanium are added to the smelting furnace under stirring. After thorough mixing, the melt is sampled again to ensure the alloy composition is properly adjusted. The mass percentages of each component are: Si: 0.34%, Fe: 0.62%, Cu: 0.02%, Mn: 1.08%, Mg: 0.31%, Cr: 0.03%, Zn: 0.01%, Ti: 0.034%, with other individual impurities ≤0.03% and total ≤0.15%. The remainder is Al. After the melt composition is adjusted to meet the requirements, the melt temperature is reduced to 729℃. High-purity argon and granular refining agent are used for refining. Each refining process takes 25 minutes. 1.25 kg of granular refining agent is used per ton of aluminum during refining. After three consecutive refining processes, slag is removed. After slag removal, the melt is allowed to stand for 25 minutes before the furnace is started. After the furnace is started, the melt flows smoothly into the guide channel. Four sets of aluminum-titanium-boron wires are added to the melt at a uniform speed. 1.8 kg of aluminum-titanium-boron wires are added per ton of aluminum melt. The melt flows into the SNIIF degassing box through the guide channel for online degassing. Granular refining agent is introduced into the degassing box. 0.4 kg of granular refining agent is used per ton of aluminum. The refined melt is filtered online through a two-stage plate filter box with filter plates of 30+30 mesh and 40+50 mesh, respectively. Then, it enters the front box through a vertical flow stabilizer. S2, Continuous Casting: The melt temperature in the front box is 680℃. The melt in the front box flows into the casting cavity of the casting machine through the casting nozzle. The melt solidifies in the casting cavity to form a billet. The billet exits the plate as the upper and lower steel strips rotate in the same direction. The casting speed is 8.9m / min, and the billet thickness is 19mm. Graphite emulsion is sprayed onto the steel strip at the billet exit position. The ratio of water to graphite emulsion in the graphite emulsion is 29:1, and the graphite emulsion spraying amount is 55ml / min. After graphite spraying, an electromagnetic induction device is used to heat the steel strip, and the steel strip temperature is 102℃. S3. Continuous rolling: The billet obtained in step S2 is fed into a three-stand rolling mill for rolling. The billet exit thickness of the first stand of the three-stand rolling mill is 9.2 mm, the billet exit thickness of the second stand of the three-stand rolling mill is 4.7 mm, and the billet exit thickness of the third stand of the three-stand rolling mill is 2.6 mm. After the billet exits the three-stand rolling mill, the residual emulsion on the end face of the billet is removed by a vacuum cleaner to ensure that there is no residual emulsion dripping from the end face. The billet exiting the third stand of the three-stand rolling mill is coiled into a coil. A 605 sleeve is built into the billet coil to facilitate suspended annealing. S4. Intermediate Annealing: The billet coil obtained in step S3 is suspended in a nitrogen-protected annealing furnace for annealing. The nitrogen concentration is 99.86%. During annealing, the aluminum coil is punched and the temperature is measured. The annealing process is set according to the measured aluminum coil temperature. The annealing process is as follows: the furnace temperature is raised to 550°C after two hours. After the metal temperature rises to 440°C, it is held at that temperature for 6 hours. Finally, the furnace temperature is lowered to 160°C and the coil is taken out of the furnace and allowed to cool naturally to room temperature. S5. Cold and Foil Rolling: The aluminum coils that have been annealed in the intermediate furnace are cooled to 40°C and directly rolled on the cold rolling mill. The cold rolling mill rolls have a roughness of 0.42µm. After 6 passes, a base material with a thickness of 0.2mm is obtained. The base material is then transferred to a slitting machine for edge trimming. The trimmed cold-rolled coils are then transferred to an aluminum foil rolling mill for rolling. The foil rolling mill rolls have a roughness of 0.28µm. After 2 passes, an aluminum foil coil with a thickness of 0.078mm is obtained. During cold rolling, each coil is rolled twice on the same set of rolls in the cold rolling mill. During foil rolling, each coil is rolled once on the same set of rolls in the foil rolling mill. S6. Finished product annealing: The 0.078mm aluminum foil roll obtained in step S5 is placed in an annealing furnace for finished product annealing. The relative humidity of the air in the annealing furnace is 2%RH. After two hours of uniform heating to 240℃, and holding under negative pressure for 4 hours, the temperature is slowly increased to 315℃ for two hours, and held under positive pressure for 38 hours. Finally, the furnace temperature is reduced to 170℃ and the product is taken out of the furnace and allowed to cool naturally to room temperature. S7. Coating: The annealed and cooled aluminum foil rolls are coated on both sides using a coating machine at a speed of 120m / min. The aluminum foil is first degreased in a degreasing tank to remove surface grease, then rinsed with clean water in a washing tank, and squeezed dry with a squeezing roller. After drying in a small oven at a temperature controlled at 480℃, it is coated with primer on both sides using a base coat roller. The primer coating is then dried in a large oven at a metal plate temperature of 245℃. The weight of a single layer of corrosion-resistant base coat is 0.75g / ㎡. Finally, the topcoat is coated on both sides using a top coat roller. The topcoat coating is then dried in a large oven at a metal plate temperature of 230℃. The weight of a single layer of hydrophilic topcoat is 0.22g / ㎡. The cleaned, primer-coated, and top-coated aluminum foil is stretched and wound into a roll using a winding device to obtain a corrosion-resistant hydrophilic aluminum roll with uniform color and good shape. S8. Slitting: Transfer the coated product from step S7 to a single-cutting machine to trim the edges. Trim approximately 6mm from each side. The slitting product should have a roll-off error and a tower shape of less than 0.5mm. The slitting speed is 240m / min. Online inspection of materials should be carried out during slitting. The upper and lower surfaces of the slitting product should be free of uncoated areas and color differences. S9. Quality Inspection: Take a small sample of the finished aluminum foil for testing. The tensile strength of the finished aluminum foil is 141MPa, the elongation is 24%, and the cupping is 6.7mm. The initial hydrophilicity angle of the coating of the finished product is 9.1°. After 2000h salt spray test, there are no perforations in the aluminum foil. After passing the inspection, it is packaged according to the packaging requirements.

[0021] Example 3 The method for producing ultra-thin, corrosion-resistant, hydrophilic heat dissipation foil for air conditioners using magnesium-aluminum alloy waste includes the following steps: S1. Smelting: 60% (by weight) of recycled aluminum can scrap and 40% (by weight) of molten aluminum are sequentially added to the smelting furnace and heated and remelted to prepare an aluminum melt at a temperature of 765℃. The melt is sampled and tested for alloy composition. Based on the test results, quick-dissolving silicon, iron, copper, manganese, magnesium ingots, and titanium are added to the smelting furnace under stirring. After thorough mixing, the melt is sampled again to ensure the alloy composition is properly adjusted. The mass percentages of each component are: Si: 0.28%, Fe: 0.69%, Cu: 0.03%, Mn: 1.13%, Mg: 0.27%, Cr: 0.02%, Zn: 0.04%, Ti: 0.021%, other individual impurities ≤0.03%, total ≤0.15%, balance being Al. After the melt composition is adjusted to meet the requirements, the melt temperature is reduced to 725℃. High-purity argon and granular refining agent are used for refining. Each refining process takes 25 minutes, and 1.0 kg of granular refining agent is used per ton of aluminum. After three consecutive refining processes, slag is removed. After slag removal, the melt is allowed to stand for 29 minutes before the furnace is started. After the furnace is started, the melt flows smoothly into the guide channel. Four sets of aluminum-titanium-boron wires are added to the melt at a uniform speed. The amount of aluminum-titanium-boron wire added is 1.9 kg of aluminum-titanium-boron wire per ton of aluminum melt. The melt flows into the SNIIF degassing box through the guide channel for online degassing. Granular refining agent is introduced into the degassing box, and 0.5 kg of granular refining agent is used per ton of aluminum. The refined melt is filtered online through a two-stage plate filter box with filter plates of 30+30 mesh and 40+50 mesh, respectively. Then it enters the front box through a vertical flow stabilizer. S2, Continuous Casting: The melt temperature in the forebox is 675℃. The melt in the forebox flows into the casting cavity of the casting machine through the casting nozzle. The melt solidifies in the casting cavity to form a billet. The billet exits the plate as the upper and lower steel strips rotate in the same direction. The casting speed is 8.5m / min, and the billet thickness is 19mm. Graphite emulsion is sprayed onto the steel strip at the billet exit position. The ratio of water to graphite emulsion in the graphite emulsion is 25:1, and the graphite emulsion spraying amount is 45ml / min. After graphite spraying, an electromagnetic induction device is used to heat the steel strip, and the steel strip temperature is 95℃. S3. Continuous rolling: The billet obtained in step S2 is fed into a three-stand continuous rolling mill for rolling. The billet exit thickness of the first stand of the three-stand continuous rolling mill is 9.8 mm, the billet exit thickness of the second stand of the three-stand continuous rolling mill is 5.2 mm, and the billet exit thickness of the third stand of the three-stand continuous rolling mill is 2.9 mm. After the billet exits the three-stand continuous rolling mill, a vacuum cleaner is used to remove the residual emulsion on the end face of the billet to ensure that there is no residual emulsion dripping on the end face. The billet exiting the third stand of the three-stand continuous rolling mill is coiled into a coil. A 605 sleeve is built into the billet coil to facilitate suspended annealing. S4. Intermediate Annealing: The billet coil obtained in step S3 is suspended in a nitrogen-protected annealing furnace for annealing. The nitrogen concentration is 99.89%. During annealing, the aluminum coil is punched and the temperature is measured. The annealing process is set according to the measured aluminum coil temperature. The annealing process is as follows: the furnace temperature is raised to 510°C after two hours. After the metal temperature is raised to 440°C, it is held for 6 hours. Finally, the furnace temperature is uniformly reduced to 150°C and the coil is taken out of the furnace and allowed to cool naturally to room temperature. S5. Cold and Foil Rolling: The aluminum coils that have been annealed in the intermediate furnace are cooled to 40°C and directly rolled on the cold rolling mill. The cold rolling mill rolls have a roughness of 0.42µm. After 6 passes, a base material with a thickness of 0.2mm is obtained. The base material is then transferred to a slitting machine for edge trimming. The trimmed cold-rolled coils are then transferred to an aluminum foil rolling mill for rolling. The foil rolling mill rolls have a roughness of 0.35µm. After 2 passes, an aluminum foil coil with a thickness of 0.078mm is obtained. During cold rolling, each coil is rolled twice on the same set of rolls in the cold rolling mill. During foil rolling, each coil is rolled once on the same set of rolls in the foil rolling mill. S6. Finished product annealing: The 0.078mm aluminum foil roll obtained in step S5 is placed in an annealing furnace for finished product annealing. The relative humidity of the air in the annealing furnace is 2%RH. After two hours of uniform heating to 240℃, and holding under negative pressure for 5 hours, the temperature is slowly increased to 350℃ for two hours, and held under positive pressure for 35 hours. Finally, the furnace temperature is reduced to 170℃ and the product is taken out of the furnace and allowed to cool naturally to room temperature. S7. Coating: The annealed and cooled aluminum foil rolls are coated on both sides using a coating machine at a speed of 120m / min. The aluminum foil is first degreased in a degreasing tank to remove surface grease, then rinsed with clean water in a washing tank, and squeezed dry with a squeezing roller. After drying in a small oven at a temperature controlled at 450℃, it is coated with primer on both sides using a base coat roller. The primer coating is then dried in a large oven at a metal plate temperature of 225℃. The weight of a single layer of corrosion-resistant base coat is 0.76g / ㎡. Finally, the topcoat is coated on both sides using a top coat roller. The topcoat coating is then dried in a large oven at a metal plate temperature of 220℃. The weight of a single layer of hydrophilic topcoat is 0.30g / ㎡. The cleaned, primer-coated, and top-coated aluminum foil is stretched and wound into a roll using a winding device to obtain a corrosion-resistant hydrophilic aluminum roll with uniform color and good shape. S8. Slitting: Transfer the coated product from step S7 to a single-cutting machine to trim the edges. Trim approximately 6mm from each side. The slitting product should have a roll-off error and a tower shape of less than 0.5mm. The slitting speed is 240m / min. Online inspection of materials should be carried out during slitting. The upper and lower surfaces of the slitting product should be free of uncoated areas and color differences. S9. Quality Inspection: Take a small sample of the finished aluminum foil for testing. The tensile strength of the finished aluminum foil is 139MPa, the elongation is 23%, and the cupping is 6.5mm. The initial hydrophilicity angle of the coating of the finished product is 9.1°. After 2000h salt spray test, there are no perforations in the aluminum foil. After passing the inspection, it is packaged according to the packaging requirements.

[0022] The parts of this invention not described in detail are prior art.

[0023] The embodiments selected herein for the purpose of disclosing the inventive objectives are currently considered suitable; however, it should be understood that the invention is intended to include all variations and modifications of the embodiments that fall within the scope of this concept and invention.

Claims

1. A method for producing ultra-thin, corrosion-resistant, hydrophilic heat dissipation foil for air conditioners using magnesium-aluminum alloy waste, characterized in that... Specifically, the following steps are included: S1. Smelting: 50%–60% (by mass percentage) of recycled aluminum scrap from aluminum cans and 40%–50% of molten electrolytic aluminum are sequentially added to the smelting furnace and heated and remelted to prepare an aluminum melt. The melt is sampled and tested for alloy composition. Based on the test results, quick-dissolving silicon, iron, copper, manganese, magnesium ingots, and titanium are added to the smelting furnace under stirring. After uniform stirring, the melt is sampled again for testing to ensure the alloy composition is adjusted to meet standards. The mass percentages of each component are: Si: 0.2–0.4%, Fe: 0.5–0.7%, Cu: ≤0.1%, Mn: 1.0–1.2%, Mg: 0.2–0.4%, Cr: ≤0.1%, Zn: ≤0.1%. ≤0.1%, Ti: 0.01~0.04%, other individual impurities ≤0.03%, total ≤0.15%, balance is Al. Refining is carried out using high-purity argon + granular refining agent. Each refining session lasts 20~30 minutes. After multiple refining sessions, slag is removed. After slag removal, the furnace is allowed to stand for 20~30 minutes before starting. After starting, the melt flows steadily into the guide channel. Four sets of aluminum-titanium-boron wires are added to the melt at a uniform speed. 1.5-2.0 kg of aluminum-titanium-boron wires are added per ton of aluminum melt. The melt flows into the degassing box through the guide channel for online degassing. Granular refining agent is introduced into the degassing box. After refining, the melt is filtered online through a four-stage plate filter box and then enters the front box through a vertical flow stabilizer. S2, Continuous casting: The temperature of the melt in the front box is 672~682℃. The melt in the front box flows into the casting cavity of the casting machine through the casting nozzle. The melt solidifies in the casting cavity to form a billet. The billet is discharged from the plate as the upper and lower steel strips rotate in the same direction. The casting speed is 8.5~9.2m / min and the billet thickness is 19mm. S3. Continuous rolling: The slab obtained in step S2 is fed into a three-stand rolling mill for rolling. The slab exit thickness of the first stand of the three-stand rolling mill is 9.0-10.0 mm, the slab exit thickness of the second stand of the three-stand rolling mill is 4.5-5.5 mm, and the slab exit thickness of the third stand of the three-stand rolling mill is 2.5-3.0 mm. The slab exiting the third stand of the three-stand rolling mill is coiled into a coil. S4. Intermediate Annealing: The billet coil obtained in step S3 is suspended in a nitrogen-protected annealing furnace for annealing. Before annealing, the aluminum coil is perforated and the temperature is measured. The annealing process is set according to the measured temperature of the aluminum coil. The specific annealing process is as follows: the furnace temperature is raised to 500-550℃ after two hours, and the metal temperature is held at 400-450℃ for 6 hours. Then the furnace temperature is uniformly reduced to 150-200℃ and the coil is taken out of the furnace and allowed to cool naturally to room temperature. S5, Cold Foil Rolling: The aluminum coils that have been annealed in the intermediate furnace are cooled to below 45°C and directly rolled on the cold rolling mill. After 6 passes, a base material with a thickness of 0.2mm is obtained. The base material is then transferred to a slitting machine for edge trimming. The trimmed cold-rolled coils are then transferred to an aluminum foil rolling mill for rolling. After 2 passes, an aluminum foil coil with a thickness of 0.075 to 0.08mm is obtained. S6. Finished product annealing: Place the 0.075-0.08mm aluminum foil roll obtained in step S5 into the annealing furnace for finished product annealing. After two hours of uniform heating to 200-250℃ and holding under negative pressure for 3-6 hours, slowly heat up to 280-350℃ for two hours and hold under positive pressure for 35-45 hours. Finally, reduce the furnace temperature to 170℃ and remove from the furnace, and allow it to cool naturally to room temperature. S7. Coating: The finished annealed and cooled aluminum foil roll is coated on both sides by a coating machine at a speed of 120m / min. The aluminum foil, which has been cleaned, coated with a base coat and a top coat in sequence, is stretched and rolled up and wound into a roll by a winding device to obtain a corrosion-resistant hydrophilic aluminum roll with uniform color and good shape. S8. Slitting: Transfer the coated product from step S7 to a single-cutting machine for edge trimming. Trim 6mm on both sides. The slitting product should have less than 0.5mm of misaligned layers and tower-shaped defects. The slitting speed is 200-250m / min. Perform online material inspection during slitting to ensure that the upper and lower surfaces of the slitting product are free of coating defects and color differences. S9. Quality Inspection: Take a small sample of the finished aluminum foil for testing. The tensile strength of the finished aluminum foil is 135MPa~145MPa, the elongation is ≥21%, and the cupping is ≥6.3mm. The initial hydrophilic angle of the coating of the finished product is ≤10°. After 2000h salt spray test, the aluminum foil has no perforations. After passing the inspection, it is packaged according to the packaging requirements.

2. The method for producing ultra-thin corrosion-resistant hydrophilic foil for air conditioning heat dissipation using magnesium-aluminum alloy waste according to claim 1, characterized in that, In step S1, the melt temperature during melting in the melting furnace is 765℃~775℃. After the alloy composition is adjusted to meet the requirements, the melt temperature is maintained at 725℃~735℃.

3. The method for producing ultra-thin corrosion-resistant hydrophilic foil for air conditioning heat dissipation using magnesium-aluminum alloy waste according to claim 1, characterized in that, In step S1, when refining in the smelting furnace, 1 to 1.5 kg of granular refining agent is used per ton of aluminum, and when refining in the degassing box, 0.2 to 0.5 kg of granular refining agent is used per ton of aluminum.

4. The method for producing ultra-thin corrosion-resistant hydrophilic foil for air conditioning heat dissipation using magnesium-aluminum alloy waste according to claim 1, characterized in that, In step S2, graphite emulsion is sprayed onto the steel strip at the billet exit position. The ratio of water to graphite emulsion in the graphite emulsion is 20:1 to 30:1, and the spraying rate of graphite emulsion is 40 to 80 ml / min. After the graphite is sprayed, an electromagnetic induction device is used to heat the steel strip and control the temperature of the steel strip to 90 to 110°C.

5. The method for producing ultra-thin corrosion-resistant hydrophilic foil for air conditioning heat dissipation from magnesium-aluminum alloy waste according to claim 1, characterized in that, In step S3, after the billet is rolled off the mill, a vacuum cleaner is used to remove the residual emulsion from the end face of the billet to ensure that no residual emulsion drips from the end face.

6. The method for producing ultra-thin corrosion-resistant hydrophilic foil for air conditioning heat dissipation from magnesium-aluminum alloy waste according to claim 1, characterized in that, In step S4, the nitrogen concentration in the nitrogen furnace during intermediate annealing is ≥99.85%.

7. The method for producing ultra-thin corrosion-resistant hydrophilic foil for air conditioning heat dissipation from magnesium-aluminum alloy waste according to claim 1, characterized in that, In step S5, during cold rolling and foil rolling production, the roll roughness of the cold rolling mill is 0.35-0.45 μm, and the roll roughness of the foil rolling mill is 0.25-0.35 μm. During cold rolling, each coil of material is rolled no more than twice by the same set of rolls in the cold rolling mill, and during foil rolling, each coil of material is rolled no more than once by the same set of rolls in the foil rolling mill.

8. The method for producing ultra-thin corrosion-resistant hydrophilic foil for air conditioning heat dissipation from magnesium-aluminum alloy waste according to claim 1, characterized in that, In step S6, during the annealing of the finished product, the relative humidity of the air inside the annealing furnace is ≤4%RH.

9. The method for producing ultra-thin corrosion-resistant hydrophilic foil for air conditioning heat dissipation from magnesium-aluminum alloy waste according to claim 1, characterized in that, In step S7, during the coating process, the aluminum foil is first degreased in a degreasing tank to remove surface grease, then rinsed with clean water in a washing tank, and then squeezed dry with a squeezing roller. After drying in an oven at a temperature controlled at 400–550°C, it is coated with primer on both sides by a base coat roller and dried in an oven at a temperature of 210–250°C. Finally, it is coated with topcoat on both sides by a top coat roller and dried in an oven at a temperature of 215–255°C.

10. The method for producing ultra-thin corrosion-resistant hydrophilic foil for air conditioning heat dissipation from magnesium-aluminum alloy waste according to claim 1, characterized in that, In step S7, the weight of the single-layer corrosion-resistant primer film is 0.6-0.8 g / m², and the weight of the single-layer hydrophilic topcoat film is 0.2-0.3 g / m².