Aluminum foil fin and air conditioner radiator made of 7072 aluminum alloy

Abstract

The present invention provides an aluminum foil fin and an air conditioner heat exchanger made from 7072 aluminum alloy. The aluminum foil fin processing method specifically includes: adding aluminum ingots and alloy additives according to the composition requirements of the 7072 aluminum alloy into a smelting furnace, heating and melting to obtain aluminum alloy liquid, injecting the liquid into a casting and rolling mill, and continuously casting and rolling it into a cast-rolled coil with a thickness of 6.0-8.0 mm. After homogenization annealing, the coil is cold-rolled to a thickness of 0.4-0.6 mm, and then cold-rolled to a thickness of 0.08-0.1 mm. After the finished product is annealed, the aluminum foil fin is obtained. The present invention proposes an aluminum foil fin and an air-conditioning heat exchanger made from 7072 aluminum alloy. By processing the 7072 alloy into aluminum foil fins, the fins are combined with aluminum tubes that replace copper tubes and used as air-conditioning radiators. Since the 7072 alloy contains an appropriate amount of Zn, the aluminum foil fins have a lower corrosion potential than the aluminum tubes. Therefore, they can serve as sacrificial anodes to protect the aluminum tubes from corrosion, ultimately significantly improving the corrosion resistance of the obtained air-conditioning heat exchanger and extending the life of the radiator.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy casting, and in particular to an aluminum foil fin and an air conditioner radiator made from 7072 aluminum alloy. Background Art

[0002] Aluminum foil is widely used in electronics, electromechanics, aerospace, packaging, construction and other industries due to its excellent thermal conductivity, easy processing, low specific gravity, low price, pollution-free and recyclable properties.

[0003] Currently, most air conditioner radiators are fin-and-tube heat exchangers, an improvement on the tubular heat exchanger with a larger heat exchange area. This product is widely used in air conditioning equipment. Currently, the most common fin-and-tube heat exchanger consists of multiple U-shaped copper tubes with welded elbows at the open ends. The U-shaped tubes are covered with numerous aluminum foil sheets, and each end of the U-shaped tube is equipped with supporting end plates with through-holes that mate with the U-shaped tubes. During production, the bent U-shaped copper tube is first inserted into the through-holes of one end plate and the multiple aluminum foil sheets as required. Then, the other end plate with through-holes is connected to the open end of the U-shaped tube.

[0004] Replacing copper tubes with aluminum tubes to reduce production costs is a major market research direction. However, directly connecting aluminum tubes with existing aluminum foil for use in air conditioning heat exchangers can cause corrosion of both the tubes and the foil fins. Once the aluminum tubes corrode, the entire radiator collapses.

[0005] Because 7072 aluminum alloy contains an appropriate amount of Zn, it can reduce the alloy's corrosion potential and increase its corrosion current density. This makes it suitable for use as a sacrificial anode material in corrosion-resistant coverings, thereby protecting the adjacent core material. Therefore, if 7072 aluminum alloy could be processed into aluminum foil fins to replace existing aluminum foil, the fins would act as sacrificial anodes to protect the aluminum tubes, thereby extending the life of the radiator. However, the prior art has not yet disclosed how to process 7072 aluminum alloy into aluminum foil fins. Summary of the Invention

[0006] Based on the technical problems existing in the background technology, the present invention proposes an aluminum foil fin and an air-conditioning heat exchanger made of 7072 aluminum alloy. By processing the 7072 alloy into aluminum foil fins, the fins are connected with aluminum tubes instead of copper tubes to be used as air-conditioning radiators. Since the 7072 alloy contains an appropriate amount of Zn element, the aluminum foil fins made therefrom have a lower corrosion potential than the aluminum tubes. Therefore, they can be used as sacrificial anodes to protect the aluminum tubes from corrosion, ultimately significantly improving the corrosion resistance of the obtained air-conditioning heat exchanger and extending the life of the radiator.

[0007] The present invention proposes an aluminum foil fin made of 7072 aluminum alloy, and the processing method thereof specifically comprises the following steps:

[0008] S1. Melting: Add aluminum ingots and alloy additives according to the composition requirements of 7072 aluminum alloy into a melting furnace, heat and melt, and obtain aluminum alloy liquid after deslagging, refining, standing, and filtering;

[0009] S2, casting and rolling: injecting the above aluminum alloy liquid into a casting and rolling mill, and continuously casting and rolling into a cast and rolled coil with a thickness of 6.0-8.0 mm;

[0010] S3, homogenization annealing: placing the cast-rolled coil into a heating furnace for homogenization annealing to obtain an aluminum coil;

[0011] S4, cold rolling: placing the aluminum coil in a cold rolling mill and cold rolling it to a thickness of 0.4-0.6 mm, and then placing it in a heating furnace for intermediate annealing to obtain a cold-rolled billet;

[0012] S5, foil rolling: placing the cold-rolled billet into an aluminum foil rolling mill and cold-rolling the billet to a thickness of 0.08-0.1 mm to obtain an aluminum foil billet;

[0013] S6, finished product annealing: placing the aluminum foil blank into a heating furnace for finished product annealing treatment to obtain the aluminum foil fin.

[0014] Preferably, in step S1, the alloy composition of the 7072 aluminum alloy includes, by mass percentage, Fe+Si: ≤0.7%, Cu: 0.05-0.10%, Mn: ≤0.1%, Mg: ≤0.1%, Zn: 0.9-1.2%, and the balance is Al;

[0015] Preferably, the alloy composition of the 7072 aluminum alloy further includes: Ti: 0.06-0.11%. In this case, the contents of Fe and Si in the alloy composition satisfy: Fe / Si=10-15.

[0016] In the present invention, a certain amount of Ti is added to the formula of the traditional 7072 aluminum alloy, and the Fe / Si content ratio is controlled to be 10-15, thereby improving the strength and plasticity of the aluminum foil product processed from the 7072 aluminum alloy and optimizing the deep drawing performance: since the precipitated phase in the traditional 7072 aluminum alloy is an AlFeSi phase (Al: 71.89wt%, Fe: 25.46wt%, Si: 2.65wt%), after adding a certain amount of Ti element, the precipitated phase is an AlFeSiTi phase (Al: 97.39wt%, Fe: 2.47wt%, Si: 0 .11wt%, Ti: 0.03wt%), and by comparing the precipitated phases before and after, it can be found that the content of Fe and Si elements in the precipitated phase of the latter is greatly reduced. Therefore, the addition of Ti element can promote the solid solution of Fe and Si elements into the aluminum matrix; and the inventors found that after controlling the Fe / Si content ratio to 10-15, it has a strong inhibitory effect on the diffusion behavior of Fe and Si atoms in the aluminum matrix, so that they are solid dissolved in the aluminum matrix to a greater extent, exerting the solid solution strengthening effect while also preventing intracrystalline segregation and structural inhomogeneity, thereby improving the strength and plasticity of the finished aluminum foil and optimizing the deep drawing performance.

[0017] Preferably, in step S2, during the casting and rolling, the casting and rolling temperature is 680-695° C., and the casting and rolling speed is 1000-1200 mm / min;

[0018] Preferably, before injecting the aluminum alloy liquid into the casting and rolling mill, Al-Ti-B wire is added to refine the grains.

[0019] In the present invention, by adopting appropriate casting temperature and casting speed, the quality of the cast-rolled coil is improved, the processing performance of the cast-rolled coil is improved, and the subsequent processing into aluminum foil fins is facilitated; when refining the grains, Al-5Ti-1B wire is preferably used to refine the grains.

[0020] Preferably, in step S3, the homogenization annealing treatment specifically includes: heating to 550-580°C within 8-10 hours, keeping the temperature for 10-20 hours, cooling to 360-400°C with the furnace, keeping the temperature for 5-15 hours, and cooling after being taken out of the furnace.

[0021] In the present invention, the coarse grains on the surface of the cast-rolled coil and the uneven grain size in the cross section are eliminated through homogenization annealing treatment under specific parameters, so that the final product has better comprehensive mechanical properties.

[0022] Preferably, in step S4, the cold rolling includes five passes, the first pass is pressed to 3.0-4.0 mm, the second pass is pressed to 2.0-2.5 mm, the third pass is pressed to 1.0-1.5 mm and simultaneously performs center cutting, the fourth pass is pressed to 0.7-0.9 mm, and the fifth pass is pressed to 0.4-0.6 mm;

[0023] Preferably, the cold rolling roller has a roughness Ra of 0.3-0.4 μm and a roller profile crown of 0.02-0.04 mm.

[0024] Preferably, in step S4, the intermediate annealing treatment specifically includes: heating to 200-220°C within 1-2 hours, keeping warm for 2-6 hours, heating to 520-560°C within 3-4 hours, keeping warm for 15-25 hours, cooling to 450-480°C within 1-2 hours, keeping warm for 2-4 hours, cooling to room temperature and taking out of the furnace.

[0025] Preferably, in step S5, the foil rolling includes two passes, the first pass is pressed to 0.25-0.45 mm, and the second pass is pressed to 0.08-0.1 mm;

[0026] Preferably, the foil rolling roller has a roughness Ra of 0.3-0.4 μm and a roller profile convexity of 0.03-0.045 mm.

[0027] Preferably, in step S6, the finished product annealing treatment specifically includes: heating to 280-300°C within 2-4 hours, keeping the temperature for 15-20 hours, reducing the temperature to 160-170°C, keeping the temperature for 1-2 hours and then taking out of the furnace.

[0028] The present invention also provides an air-conditioning radiator, comprising an aluminum tube and the above-mentioned aluminum foil fins arranged in series on the aluminum tube; wherein the aluminum tube has a higher corrosion potential than the aluminum foil fins.

[0029] Preferably, the aluminum tube is made of at least one aluminum alloy selected from 3005M, 3104M, 5052M or 3003M.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention optimizes the material design of the air conditioner radiator and adopts 7072 aluminum alloy to manufacture the aluminum foil fin for the radiator. The influence of the main alloying element Zn and the impurity elements Fe and Si on the forming performance and strength performance of the aluminum foil fin made of 7072 aluminum alloy is further comprehensively considered: the Zn element can reduce the corrosion potential of the aluminum alloy. The greater the addition amount, the greater the potential reduction. By controlling the Zn element content to 0.9-1.2%, the corrosion potential is avoided from being excessively reduced while the alloy performance is improved. By adding Zn to the formula of the traditional 7072 aluminum alloy, the Zn element can reduce the corrosion potential of the aluminum alloy. Adding a certain amount of Ti and controlling the Fe / Si content ratio to 10-15 have a beneficial effect on the alloy, improving the casting structure, reducing the internal component segregation of the 7072 alloy billet produced by continuous casting and rolling, reducing deformation resistance, ensuring the homogenization annealing effect, and refining the grains during annealing, thereby ensuring improved strength and plasticity of the 7072 aluminum alloy processed into aluminum foil products and optimizing deep drawing performance. Finally, by further optimizing the continuous casting process and adjusting the rolling scheme, high-performance aluminum foil fins for air conditioner radiators with excellent surface quality and uniform structure are obtained. DETAILED DESCRIPTION

[0032] Hereinafter, the technical solutions of the present invention will be described in detail through specific embodiments. However, it should be clearly stated that these embodiments are provided for illustration only and are not to be construed as limiting the scope of the present invention.

[0033] Example 1

[0034] The present embodiment proposes an aluminum foil fin made of 7072 aluminum alloy, and its processing method specifically includes the following steps:

[0035] (1) Melting: Aluminum ingots, aluminum-iron master alloy, electrolytic aluminum liquid (Fe≤0.16%, Si≤0.04%) and zinc ingots are added to the melting furnace according to the composition requirements of 7072 aluminum alloy. After heating and melting, the melting temperature is controlled to 760℃. After slag removal, they are injected into the static furnace for nitrogen refining at a refining temperature of 740℃. After refining for 20 minutes, the surface slag is removed. Then, the static furnace is kept for nitrogen refining every 2 hours, and then enters the degassing box and Al- 5Ti-1B alloy wire is subjected to grain refinement, and an amount of 2.5 kg / tAl is added. After filtering through a ceramic filter plate, an aluminum alloy liquid is obtained. The alloy composition of the aluminum alloy liquid includes, by mass percentage, Fe: 0.55%, Si: 0.05%, Cu: 0.08%, Mn: 0.1%, Mg: 0.1%, Zn: 1.1%, Ti: 0.08%, and the balance is Al, wherein the contents of Fe and Si satisfy: Fe / Si = 10-15;

[0036] (2) injecting the aluminum alloy liquid into a casting and rolling mill at a casting and rolling temperature of 690° C. and a casting and rolling speed of 1100 mm / min, and continuously casting and rolling into a cast and rolled coil with a thickness of 6.9 mm;

[0037] (3) Homogenization annealing: The cast and rolled coil is placed in a heating furnace for homogenization annealing. Specifically, the temperature is raised to 560°C within 9 hours, kept at this temperature for 15 hours, then cooled to 380°C along with the furnace, kept at this temperature for 10 hours, and then removed from the furnace for cooling to obtain an aluminum coil.

[0038] (4) Cold rolling: The aluminum coil is placed in a cold rolling mill for cold rolling. The cold rolling includes five passes, the first pass is pressed to 3.6 mm, the second pass is pressed to 2.2 mm, the third pass is pressed to 1.3 mm, and the intermediate cutting is performed at the same time. The fourth pass is pressed to 0.82 mm, and the fifth pass is pressed to 0.49 mm. The roller roughness Ra used in the cold rolling process is 0.4 μm, and the roller profile convexity is 0.03 mm. Then, the aluminum coil is placed in a heating furnace for intermediate annealing treatment. Specifically, the temperature is raised to 210°C within 1.5 hours and kept at this temperature for 4 hours. The temperature is raised to 540°C within 3.5 hours and kept at this temperature for 20 hours. The temperature is lowered to 460°C within 1.5 hours and kept at this temperature for 3 hours. The coil is cooled to room temperature and taken out of the furnace to obtain a cold-rolled billet.

[0039] (5) Foil rolling: The cold-rolled blank is placed in an aluminum foil rolling mill for foil rolling. The foil rolling process includes two passes, the first pass is pressed to 0.35 mm, and the second pass is pressed to 0.095 mm. The roller roughness Ra used in the foil rolling process is 0.3 μm, and the roller profile crown is 0.035 mm, thereby obtaining an aluminum foil blank.

[0040] (6) Finished product annealing: The aluminum foil blank is placed in a heating furnace for finished product annealing treatment, heated to 290°C within 3 hours, kept warm for 16 hours, then cooled to 165°C, kept warm for 1.5 hours, and then taken out of the furnace to obtain the aluminum foil fin.

[0041] The mechanical properties of the aluminum foil prepared in this embodiment are as follows: tensile strength 115 MPa, elongation 32.0%, and cupping value 8.2 mm.

[0042] Example 2

[0043] The present embodiment proposes an aluminum foil fin made of 7072 aluminum alloy, and its processing method specifically includes the following steps:

[0044] (1) Melting: Aluminum ingots, aluminum-iron master alloy, electrolytic aluminum liquid (Fe≤0.16%, Si≤0.04%) and zinc ingots are added to the melting furnace according to the composition requirements of 7072 aluminum alloy. After heating and melting, the melting temperature is controlled to 760℃. After slag removal, they are injected into the static furnace for nitrogen refining at a refining temperature of 740℃. After refining for 20 minutes, the surface slag is removed. Then, the static furnace is kept for nitrogen refining every 2 hours, and then enters the degassing box and Al is added. -5Ti-1B alloy wire is added in an amount of 2kg / tAl for grain refinement, and filtered through a ceramic filter plate to obtain an aluminum alloy liquid, wherein the alloy composition of the aluminum alloy liquid comprises, by mass percentage, Fe: 0.5%, Si: 0.05%, Cu: 0.05%, Mn: 0.08%, Mg: 0.1%, Zn: 0.9%, Ti: 0.11%, and the balance is Al, wherein the contents of Fe and Si satisfy: Fe / Si=10-15;

[0045] (2) injecting the aluminum alloy liquid into a casting and rolling mill at a casting and rolling temperature of 680° C. and a casting and rolling speed of 1200 mm / min, and continuously casting and rolling into a cast and rolled coil with a thickness of 7.4 mm;

[0046] (3) Homogenization annealing: The cast and rolled coil is placed in a heating furnace for homogenization annealing. Specifically, the temperature is raised to 580°C within 8 hours, kept at this temperature for 20 hours, then cooled to 400°C with the furnace, kept at this temperature for 5 hours, and then taken out of the furnace and cooled to obtain an aluminum coil.

[0047] (4) Cold rolling: The aluminum coil is placed in a cold rolling mill for cold rolling. The cold rolling process includes five passes, the first pass is pressed to 3.1 mm, the second pass is pressed to 2.5 mm, the third pass is pressed to 1.0 mm, and the intermediate cutting is performed at the same time. The fourth pass is pressed to 0.89 mm, and the fifth pass is pressed to 0.41 mm. The roughness Ra of the roller used in the cold rolling process is 0.3 μm, and the roller profile convexity is 0.04 mm. The aluminum coil is then placed in a heating furnace for intermediate annealing treatment. Specifically, the temperature is raised to 220°C within 1 hour and kept at this temperature for 2 hours. The temperature is raised to 520°C within 4 hours and kept at this temperature for 25 hours. The temperature is lowered to 480°C within 1 hour and kept at this temperature for 2 hours. The coil is cooled to room temperature and then taken out of the furnace to obtain a cold-rolled billet.

[0048] (5) Foil rolling: The cold-rolled blank is placed in an aluminum foil rolling mill for foil rolling. The foil rolling process includes two passes, the first pass is pressed to 0.25 mm, and the second pass is pressed to 0.085 mm. The roller roughness Ra used in the foil rolling process is 0.4 μm, and the roller profile crown is 0.03 mm, to obtain an aluminum foil blank.

[0049] (6) Finished product annealing: The aluminum foil blank is placed in a heating furnace for finished product annealing treatment, heated to 300°C within 2 hours, kept warm for 12 hours, then cooled to 170°C, kept warm for 1 hour, and then taken out of the furnace to obtain the aluminum foil fin.

[0050] The mechanical properties of the aluminum foil prepared in this embodiment are as follows: tensile strength 99 MPa, elongation 34.0%, and cupping value 8.0 mm.

[0051] Example 3

[0052] The present embodiment proposes an aluminum foil fin made of 7072 aluminum alloy, and its processing method specifically includes the following steps:

[0053] (1) Melting: Aluminum ingots, aluminum-iron master alloy, electrolytic aluminum liquid (Fe≤0.16%, Si≤0.04%) and zinc ingots are added to the melting furnace according to the composition requirements of 7072 aluminum alloy. After heating and melting, the melting temperature is controlled to 760℃. After slag removal, they are injected into the static furnace for nitrogen refining at a refining temperature of 740℃. After refining for 20 minutes, the surface slag is removed. Then, the static furnace is kept for nitrogen refining every 2 hours, and then enters the degassing box and Al is added. -5Ti-1B alloy wire is added in an amount of 3kg / tAl to refine the grains, and filtered through a ceramic filter plate to obtain an aluminum alloy liquid, wherein the alloy composition of the aluminum alloy liquid comprises, by mass percentage, Fe: 0.6%, Si: 0.04%, Cu: 0.10%, Mn: 0.1%, Mg: 0.09%, Zn: 1.2%, Ti: 0.06%, and the balance is Al, wherein the contents of Fe and Si satisfy: Fe / Si = 10-15;

[0054] (2) injecting the aluminum alloy liquid into a casting and rolling mill at a casting and rolling temperature of 695° C. and a casting and rolling speed of 1000 mm / min, and continuously casting and rolling into a cast and rolled coil with a thickness of 7.8 mm;

[0055] (3) Homogenization annealing: The cast coil is placed in a heating furnace for homogenization annealing. Specifically, the temperature is raised to 550°C within 10 hours, kept at this temperature for 10 hours, then cooled to 360°C with the furnace, kept at this temperature for 15 hours, and then taken out of the furnace for cooling to obtain an aluminum coil.

[0056] (4) Cold rolling: The aluminum coil is placed in a cold rolling mill for cold rolling. The cold rolling includes five passes, the first pass is pressed to 3.8 mm, the second pass is pressed to 2.1 mm, the third pass is pressed to 1.5 mm, and the intermediate cutting is performed at the same time. The fourth pass is pressed to 0.72 mm, and the fifth pass is pressed to 0.56 mm. The roller roughness Ra used in the cold rolling process is 0.4 μm, and the roller profile convexity is 0.03 mm. Then, the aluminum coil is placed in a heating furnace for intermediate annealing treatment. Specifically, the temperature is raised to 200°C within 2 hours and kept at this temperature for 6 hours. The temperature is raised to 560°C within 3 hours and kept at this temperature for 15 hours. The temperature is lowered to 450°C within 2 hours and kept at this temperature for 4 hours. The coil is cooled to room temperature and then taken out of the furnace to obtain a cold-rolled billet.

[0057] (5) Foil rolling: The cold-rolled blank is placed in an aluminum foil rolling mill for foil rolling. The foil rolling process includes two passes, the first pass is pressed to 0.43 mm, and the second pass is pressed to 0.1 mm. The roller roughness Ra used in the foil rolling process is 0.3 μm, and the roller profile crown is 0.045 mm, thereby obtaining an aluminum foil blank.

[0058] (6) Finished product annealing: The aluminum foil blank is placed in a heating furnace for finished product annealing treatment, heated to 280°C within 4 hours, kept warm for 20 hours, then cooled to 160°C, kept warm for 2 hours, and then taken out of the furnace to obtain the aluminum foil fin.

[0059] The mechanical properties of the aluminum foil prepared in this embodiment are as follows: tensile strength 110 MPa, elongation 30.0%, and cupping value 8.1 mm.

[0060] Comparative Example 1

[0061] The present embodiment proposes an aluminum foil fin made of 7072 aluminum alloy, and its processing method specifically includes the following steps:

[0062] (1) Melting: Aluminum ingots, aluminum-iron master alloy, electrolytic aluminum liquid (Fe≤0.16%, Si≤0.04%) and zinc ingots are added to a melting furnace according to the composition requirements of 7072 aluminum alloy. After heating and melting, the melting temperature is controlled to 760°C. After slag removal, the ingots are injected into a static furnace for nitrogen refining at a refining temperature of 740°C. After refining for 20 minutes, the surface slag is removed. The ingots are then placed in a static furnace for nitrogen refining every 2 hours. The ingots are then put into a degassing box, and Al-5Ti-1B alloy wire is added for grain refinement in an amount of 2.5 kg / tAl. After filtering with a ceramic filter plate, an aluminum alloy liquid is obtained. The alloy composition of the aluminum alloy liquid includes, by mass percentage, Fe: 0.35%, Si: 0.25%, Cu: 0.08%, Mn: 0.1%, Mg: 0.1%, Zn: 1.1%, Ti: 0.08%, and the balance is Al;

[0063] (2) injecting the aluminum alloy liquid into a casting and rolling mill at a casting and rolling temperature of 690° C. and a casting and rolling speed of 1100 mm / min, and continuously casting and rolling into a cast and rolled coil with a thickness of 6.9 mm;

[0064] (3) Homogenization annealing: The cast and rolled coil is placed in a heating furnace for homogenization annealing. Specifically, the temperature is raised to 560°C within 9 hours, kept at this temperature for 15 hours, then cooled to 380°C along with the furnace, kept at this temperature for 10 hours, and then removed from the furnace for cooling to obtain an aluminum coil.

[0065] (4) Cold rolling: The aluminum coil is placed in a cold rolling mill for cold rolling. The cold rolling includes five passes, the first pass is pressed to 3.6 mm, the second pass is pressed to 2.2 mm, the third pass is pressed to 1.3 mm, and the intermediate cutting is performed at the same time. The fourth pass is pressed to 0.82 mm, and the fifth pass is pressed to 0.49 mm. The roller roughness Ra used in the cold rolling process is 0.4 μm, and the roller profile convexity is 0.03 mm. Then, the aluminum coil is placed in a heating furnace for intermediate annealing treatment. Specifically, the temperature is raised to 210°C within 1.5 hours and kept at this temperature for 4 hours. The temperature is raised to 540°C within 3.5 hours and kept at this temperature for 20 hours. The temperature is lowered to 460°C within 1.5 hours and kept at this temperature for 3 hours. The coil is cooled to room temperature and taken out of the furnace to obtain a cold-rolled billet.

[0066] (5) Foil rolling: The cold-rolled blank is placed in an aluminum foil rolling mill for foil rolling. The foil rolling process includes two passes, the first pass is pressed to 0.35 mm, and the second pass is pressed to 0.095 mm. The roller roughness Ra used in the foil rolling process is 0.3 μm, and the roller profile crown is 0.035 mm, thereby obtaining an aluminum foil blank.

[0067] (6) Finished product annealing: The aluminum foil blank is placed in a heating furnace for finished product annealing treatment, heated to 290°C within 3 hours, kept warm for 16 hours, then cooled to 165°C, kept warm for 1.5 hours, and then taken out of the furnace to obtain the aluminum foil fin.

[0068] The mechanical properties of the aluminum foil prepared in this comparative example are as follows: tensile strength 98 MPa, elongation 23.0%, and cupping value 6.9 mm.

[0069] It can be seen from the contents of the above embodiments and comparative examples that the present invention improves the deep drawing performance of the aluminum foil by reasonably selecting the element contents of Fe, Si, and Ti, and increases the elongation of the air-conditioning foil product by 39% and the cupping value by 19%. The present invention can process 7072 aluminum alloy into air-conditioning aluminum foil with better elongation and cupping value.

[0070] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. An aluminum foil fin made of 7072 aluminum alloy, characterized in that: The processing method specifically includes the following steps: S1. Melting: Add aluminum ingots and alloy additives according to the composition requirements of 7072 aluminum alloy into a melting furnace, heat and melt, and obtain aluminum alloy liquid after deslagging, refining, standing, and filtering; S2, casting and rolling: injecting the above aluminum alloy liquid into a casting and rolling mill, and continuously casting and rolling into a cast and rolled coil with a thickness of 6.0-8.0 mm; S3, homogenization annealing: placing the cast-rolled coil into a heating furnace for homogenization annealing to obtain an aluminum coil; S4, cold rolling: placing the aluminum coil in a cold rolling mill and cold rolling it to a thickness of 0.4-0.6 mm, and then placing it in a heating furnace for intermediate annealing to obtain a cold-rolled billet; S5, foil rolling: placing the cold-rolled billet into an aluminum foil rolling mill and cold-rolling the billet to a thickness of 0.08-0.1 mm to obtain an aluminum foil billet; S6, finished product annealing: placing the aluminum foil blank into a heating furnace for finished product annealing treatment to obtain the aluminum foil fin; In step S1, the alloy composition of the 7072 aluminum alloy includes, by mass percentage, the following: Fe: 0.55% or 0.6%, Si: 0.04% or 0.05%, Cu: 0.05-0.10%, Mn: 0.08-0.1%, Mg: 0.09-0.1%, Zn: 0.9-1.2%, and the balance is Al; The alloy composition of the 7072 aluminum alloy further includes: Ti: 0.06-0.11%. In this case, the contents of Fe and Si in the alloy composition satisfy: Fe / Si=10-15; In step S4, the intermediate annealing treatment specifically includes: heating to 200-220°C within 1-2 hours, keeping warm for 2-6 hours, heating to 520-560°C within 3-4 hours, keeping warm for 15-25 hours, cooling to 450-480°C within 1-2 hours, keeping warm for 2-4 hours, cooling to room temperature and taking out of the furnace.

2. The aluminum foil fin made of 7072 aluminum alloy according to claim 1, characterized in that: In step S2, during the casting and rolling, the casting and rolling temperature is 680-695° C., and the casting and rolling speed is 1000-1200 mm / min; Before the aluminum alloy liquid is injected into the casting and rolling mill, the aluminum alloy liquid is added - Ti-B wires refine the grains.

3. The aluminum foil fin made of 7072 aluminum alloy according to claim 1 or 2, characterized in that: In step S3, the homogenization annealing treatment specifically includes: heating to 550-580°C within 8-10 hours, keeping the temperature for 10-20 hours, cooling to 360-400°C with the furnace, keeping the temperature for 5-15 hours, and cooling after being taken out of the furnace.

4. The aluminum foil fin made of 7072 aluminum alloy according to claim 1 or 2, characterized in that: In step S4, the cold rolling includes five passes, the first pass is pressed to 3.0-4.0 mm, the second pass is pressed to 2.0-2.5 mm, the third pass is pressed to 1.0-1.5 mm, and the center cut is performed at the same time, the fourth pass is pressed to 0.7-0.9 mm, and the fifth pass is pressed to 0.4-0.6 mm; The cold rolling roller has a roughness Ra of 0.3-0.4 μm and a roller profile convexity of 0.02-0.04 mm.

5. The aluminum foil fin made of 7072 aluminum alloy according to claim 1 or 2, characterized in that: In step S5, the foil rolling includes two passes, the first pass is pressed to 0.25-0.45 mm, and the second pass is pressed to 0.08-0.1 mm; The foil rolling roller has a roughness Ra of 0.3-0.4 μm and a roller profile convexity of 0.03-0.045 mm.

6. The aluminum foil fin made of 7072 aluminum alloy according to claim 1 or 2, characterized in that: In step S6, the finished product annealing treatment specifically includes: heating to 280-300°C within 2-4 hours, keeping the temperature for 15-20 hours, reducing the temperature to 160-170°C, keeping the temperature for 1-2 hours and then taking out of the furnace.

7. An air conditioning radiator, characterized in that: The invention comprises an aluminum tube and the aluminum foil fin according to any one of claims 1 to 6 which is arranged in series on the aluminum tube; wherein the aluminum tube has a higher corrosion potential than the aluminum foil fin.

8. The air conditioning radiator according to claim 7, characterized in that: The aluminum tube is made of at least one aluminum alloy selected from 3005M, 3104M, 5052M and 3003M.