Extrusion method for regenerated aluminum profile with complex section

Abstract

The invention discloses an extrusion method of a regenerated aluminum profile with a complex section, and relates to the technical field of aluminum profile processing, and the extrusion method comprises the following operation steps: S1, raw material pretreatment: crushing waste aluminum subjected to impurity removal to form aluminum particles, and cleaning the aluminum particles by using a sodium hydroxide solution with the mass concentration of 5-8% at the temperature of 50-60 DEG C for 15-20 minutes; according to the extrusion method for the regenerated aluminum profile with the complex section, various impurities in waste aluminum are effectively removed through a manual and mechanical combined sorting mode in cooperation with multiple impurity removal technologies such as magnetic separation, eddy current separation and wind power separation, and then standardized treatment such as crushing, alkali washing and drying is conducted, so that efficient recycling of regenerated aluminum resources is achieved, resource waste is reduced, and the production cost is reduced. And a clean and uniform raw material basis is provided for subsequent procedures, profile defects caused by impurity residues are avoided from the source, and the raw material utilization rate and the product percent of pass are increased.

Description

Technical Field

[0001] This invention relates to the field of aluminum profile processing technology, and in particular to a method for extruding recycled aluminum profiles with complex cross-sections. Background Technology

[0002] In the field of complex cross-section recycled aluminum profile processing, traditional extrusion processes often face multiple technical bottlenecks. On the one hand, the sources of recycled aluminum raw materials are complex, and the content of impurities (such as iron, copper, plastics, etc.) fluctuates greatly. Existing impurity removal technologies are mostly single mechanical sorting, which is difficult to completely remove composite impurities, resulting in uneven composition of the subsequent molten material. After forming, the profile is prone to defects such as porosity and inclusions, which seriously affect the mechanical properties. On the other hand, complex cross-section structures (such as multi-cavity, irregular curved surfaces, and grooves) have the characteristics of large differences in wall thickness and high difficulty in cavity filling. Traditional molds lack targeted flow guidance design, and the melt flow is prone to "dead zone" or "overflow" phenomena, resulting in low dimensional accuracy and high surface roughness of the profile.

[0003] Meanwhile, traditional processes often employ an open-loop approach to component control, relying on manual sampling and testing. This results in delayed feedback and low adjustment precision, leading to significant batch-to-batch fluctuations in profile composition and mechanical property differences of up to ±15MPa, failing to meet the consistency requirements of high-end structural components. Furthermore, the lack of continuity between extrusion quenching and aging treatments, coupled with insufficient precision in cooling medium selection and temperature control, easily causes stress concentration within the profile, leading to warping, twisting, and other deformation problems in complex cross-sections. Subsequent shaping requires extensive machining, increasing material waste and reducing production efficiency.

[0004] Therefore, it is necessary to propose a method for extruding recycled aluminum profiles with complex cross-sections to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for extruding recycled aluminum profiles with complex cross sections to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for extruding recycled aluminum profiles with complex cross-sections, comprising the following operational steps: S1. Raw material pretreatment: The waste aluminum after impurity removal is crushed to form aluminum particles. The aluminum particles are then washed with a sodium hydroxide solution with a mass concentration of 5-8% at a temperature of 50-60℃ for 15-20 minutes. After that, they are rinsed with clean water until neutral and dried at a temperature of 120-150℃ for 2-3 hours. S2. Composition adjustment: Add intermediate alloy to the pretreated aluminum granules and mix them to form a mixed raw material; S3. Heating and melting: The mixed raw materials are heated and melted using a regenerative continuous heating furnace. The temperature is increased to 580-620℃ at a rate of 5-8℃ / min and held for 2-3 hours to obtain the molten material. S4. Extrusion molding: Molten material is extruded through an extruder and gradient extrusion die to form aluminum profiles with complex cross-sections such as multi-cavity, irregular curved surfaces, or concave and convex grooves. At the same time, the composition of the aluminum profile is detected online by laser-induced breakdown spectroscopy, and the PLC batching system provides real-time feedback to automatically fine-tune the amount of intermediate alloy added in the next batch. S5. Online quenching: The extruded aluminum profiles are quenched using a wind-mist quenching device. At the same time, a compressed air-water mixture with a water mass ratio of 10-15% is used as the cooling medium and held at a temperature of 500-530℃ for 10-15 minutes. S6. Aging treatment: The quenched aluminum profiles are aged using an electric heating aging furnace. The temperature is raised to 120-140℃ at a heating rate of 3-5℃ / min and held for 4-6 hours. The furnace temperature is calibrated every 1 hour during the process.

[0007] Preferably, in step S1, the removal of impurities from waste aluminum is carried out using a combination of manual and mechanical methods. The mechanical removal includes using a magnetic separator to generate a strong magnetic field to adsorb ferrous metal impurities from the waste aluminum, using an eddy current separator to generate an eddy current effect to separate non-ferrous metal impurities such as copper and zinc, and using a wind separator to create airflow velocity differences to remove lightweight plastic and rubber impurities.

[0008] Preferably, in S2, the intermediate alloy includes Al-20Si, Al-10Mg, Al-30Cu, and Al-15Mn, and the final percentage of the alloying elements in the total mass of the mixed raw materials is controlled within the following range: Si 0.8–1.2%, Mg 0.4–0.6%, Cu 0.1–0.2%, Mn 0.05–0.1%, with the balance being Al.

[0009] Preferably, in step S3, protective nitrogen gas supplied by a nitrogen generator is introduced into the regenerative continuous heating furnace, with a nitrogen purity ≥99.99% and an oxygen content ≤0.01% in the furnace, forming an inert atmosphere.

[0010] Preferably, in step S4, the gradient extrusion die is made of H13 hot work die steel, and the die surface is nitrided with a nitrided layer thickness of 0.1-0.2 mm and a surface hardness of 900-950 HV. The die inlet is provided with a funnel-shaped guide area.

[0011] Preferably, in step S4, the frequency of the online detection of laser-induced breakdown spectroscopy is once every 30 seconds, which is used to provide feedback on the measured values ​​of Si, Mg, Cu, and Mn elements. The measured value data is transmitted back to the PLC batching system via industrial Ethernet.

[0012] Preferably, in step S5, the cooling medium of the air-fog quenching device is evenly sprayed onto the surface of the aluminum profile through multiple sets of nozzles.

[0013] Preferably, in step S6, the electric heating aging furnace adopts a PID temperature control system, which automatically calibrates the furnace temperature every 1 hour.

[0014] Preferably, in step S1, the drying process uses a hot air circulating dryer with an air velocity controlled at 1.5-2 m / s and an aluminum particle moisture content ≤0.1%.

[0015] Preferably, in step S5, an ultrasonic vibration shaping section is set after quenching. When the surface temperature of the aluminum profile is still maintained at 180–220°C, an ultrasonic vibration with a frequency of 20–40 kHz and an amplitude of 10–30 μm is applied to the thin-walled part of the aluminum profile by a multi-point pneumatic clamping device in conjunction with an ultrasonic transducer for a duration of 30–60 s.

[0016] The technical effects and advantages of this invention are as follows: 1. This invention uses a combination of manual and mechanical sorting methods, along with multiple impurity removal technologies such as magnetic separation, eddy current separation, and wind separation, to effectively remove various impurities from waste aluminum. After standardized treatment such as crushing, alkaline washing, and drying, it not only achieves efficient recycling of recycled aluminum resources and reduces resource waste, but also provides a clean and uniform raw material base for subsequent processes, avoiding profile defects caused by impurity residues from the source, and improving raw material utilization and product qualification rate. 2. This invention relies on the precise addition of intermediate alloy and the uniform mixing process of the double cone mixer. Combined with the laser-induced breakdown spectroscopy online detection and the PLC batching system to construct a "compression-feedback-batching" closed-loop control system, it can monitor the profile composition in real time and dynamically fine-tune the batching ratio. Compared with the traditional open-loop batching mode, it significantly reduces the standard deviation of the composition, making the alloy element distribution of each profile more uniform. This effectively ensures the consistency and stability of the product composition, lays a solid foundation for the stability of subsequent mechanical properties, and meets the stringent requirements of high-end structural components for the accuracy of material composition. 3. During the extrusion molding process of this invention, the nitrogen protective atmosphere of the regenerative continuous heating furnace is used to avoid oxidation of the molten material and loss of alloying elements. Through the design of the trumpet-shaped flow guide area of ​​the gradient extrusion die and the control of the vacuum environment of the barrel, the melt is ensured to fill the cavity smoothly, reducing the entrapment of air bubbles, significantly improving the dimensional accuracy and surface finish of the profile, effectively solving the problems of uneven filling and large dimensional deviation that are easy to occur in the molding process of complex cross-section profiles, and at the same time realizing high-precision molding of complex structures such as multi-cavity and irregular curved surfaces. 4. The online air-fog quenching process of this invention can quickly fix the supersaturated solid solution inside the profile, avoiding deformation and cracking caused by excessive internal stress. The low-temperature aging treatment, through precise temperature control, promotes the uniform precipitation of strengthening phases, significantly improving the mechanical properties of the profile, such as tensile strength, yield strength, elongation, and hardness, meeting the load-bearing and impact resistance requirements of structural components. In addition, the ultrasonic vibration shaping technology introduced in the residual heat stage of quenching, combined with multi-point pneumatic clamping, can efficiently release internal stress, correct micron-level warping or twisting defects, reduce subsequent machining allowances, further improve yield, and reduce material waste and processing costs. Attached Figure Description

[0017] Figure 1 This is a flowchart of the method for extruding recycled aluminum profiles with complex cross sections according to the present invention. Detailed Implementation

[0018] This invention provides, for example Figure 1 The method for extruding recycled aluminum profiles with complex cross-sections, as shown, includes eight major steps: pretreatment, alloying, melting, extrusion, quenching, aging, ultrasonic shaping, and closed-loop composition control. First, the waste aluminum is sorted and impurities removed, crushed and cooled, alkaline washed to remove film, and dried to obtain clean raw materials. Then, an intermediate alloy is added to regulate the composition and ensure thorough mixing. Next, the aluminum is heated and melted under nitrogen protection until completely melted. Then, a nitriding gradient die is used for high-precision extrusion into complex cross-sections. Immediately after extrusion, air-fog quenching is performed to fix the microstructure. Following this, low-temperature aging is used for precipitation strengthening. Finally, ultrasonic micro-vibration is introduced during the residual heat stage of quenching to relieve stress and correct shape. The entire process is linked by an online spectral detection and batching system in a closed loop to ensure consistent composition and performance of each profile.

[0019] The specific operating steps are as follows: I. Pre-treatment of recycled aluminum raw materials: The recycled waste aluminum is sorted using a combination of manual and mechanical methods to remove plastic, rubber, and metal impurities. The mechanical methods include using a magnetic separator to generate a strong magnetic field to adsorb ferrous metals and remove ferrous impurities; using an eddy current separator to generate eddy current effect to separate non-ferrous metals, thus separating aluminum from non-metals; and using a wind-powered separator to generate airflow velocity differences to remove lightweight plastics, rubber, and other impurities, thereby improving the purity of the waste aluminum. The waste aluminum is then crushed to a particle size of 30–50 mm by a jaw crusher to form aluminum particles. During the crushing process, a circulating cooling water system is used to provide cooling water at a temperature of 20–25°C for spraying and cooling to prevent the aluminum particles from oxidizing due to friction and heating. Next, an alkaline washing tank equipped with a heating and circulation device is used to clean the surface with a sodium hydroxide solution of 5–8% by mass at a temperature of 50–60°C for 15–20 minutes to remove surface oil and oxide film. Finally, the aluminum particles are rinsed with clean water until neutral using a spray cleaning machine, and then dried using a hot air circulating dryer at a temperature of 120–150℃ for 2–3 hours to ensure that the aluminum particles are dry and clean, and to avoid bubbles or defects caused by moisture or impurities during subsequent heating.

[0020] II. Composition Adjustment: An intermediate alloy (such as Al-20Si, Al-10Mg, Al-30Cu, Al-15Mn) is added to the pretreated aluminum granules using an automatic weighing and adding device, so that the final percentage of the alloy element mass in the total mass of the raw material is controlled within the following range: Si 0.8–1.2%, Mg 0.4–0.6%, Cu 0.1–0.2%, Mn 0.05–0.1%, with the balance being Al; A double cone mixer is used to mix aluminum granules and alloys at a speed of 300 r / min for 15–20 min to ensure uniform distribution of alloying elements, form mixed raw materials, and improve the microstructure consistency and mechanical properties of subsequent molding materials.

[0021] 3. Heating and Melting: The mixed raw materials are put into a regenerative continuous heating furnace. A protective atmosphere with nitrogen purity ≥99.99% and oxygen content ≤0.01% is provided by a nitrogen generator. The mixture is heated to 580–620℃ at a heating rate of 5–8℃ / min and held for 2–3 hours to ensure that the mixed raw materials are fully melted to form a molten material with uniform composition, avoiding oxidation and loss of alloying elements, and providing a stable melt state for subsequent extrusion molding.

[0022] IV. Extrusion Molding: After the molten material is injected into the extruder through the tilting insulated flow channel, it is pushed into the electrically heated barrel, which has been preheated to 550–580℃, by the hydraulic plunger at an initial velocity of 0.2–0.4 m / s. The barrel end is equipped with a flow divider cone and a perforated plate to evenly divide the melt and filter out inclusions. Then the plunger continues to advance, so that the melt enters the gradient extrusion die made of H13 hot work die steel in a laminar flow at a pressure of 18–25MPa and a speed of 3–8mm / s. The mold inlet has a trumpet-shaped guide zone. The melt smoothly transitions through the guide zone to the cavity formed by the mold core and mold sleeve. The filling is completed in the 400-450℃ environment maintained by the mold heating furnace. Finally, it is continuously extruded from the mold opening to form multi-cavity, irregular curved surface or complex cross-section aluminum profile with concave and convex grooves. The entire process is completed under a cylinder vacuum of 0.08–0.09 MPa maintained by a vacuum pump to avoid air bubble entrapment and ensure product dimensional accuracy of ±0.1 mm and surface roughness Ra≤1.6 μm.

[0023] Simultaneously, a laser-induced breakdown spectroscopy (LIBS) online composition probe is installed at the extruder outlet to rapidly scan the profile surface every 30 seconds, providing measured values ​​of Si, Mg, Cu, and Mn within 30 seconds. The data is transmitted in real-time via industrial Ethernet to the front-end PLC batching system, where it is compared with the target range (Si 0.8–1.2%, Mg 0.4–0.6%, Cu 0.1–0.2%, Mn 0.05–0.1%) to calculate the deviation. The PLC controls an automatic weighing and dispensing device for the intermediate alloy. The system automatically fine-tunes the amount of intermediate alloy added to the next batch of aluminum granules based on the deviation, with an adjustment step of no more than 0.02%, forming a closed-loop control of "extrusion-feedback-batching". When three consecutive tests are within ±0.05% of the target median, the system determines that the batch is qualified and records the traceability code through an inkjet printer, realizing traceability of the composition of a single profile. Compared with traditional open-loop batching, the standard deviation of the composition is reduced by more than 50%, and the fluctuation range of mechanical properties is compressed from ±15MPa to ±5MPa, meeting the consistency requirements of high-end structural components.

[0024] V. Online Quenching: The extruded aluminum profiles are immediately sent into the air-mist quenching device. A mixture of compressed air and water is provided by an air compressor and a high-pressure water pump as the cooling medium, in which the mass of water accounts for 10-15% of the total mass of the cooling medium. Air-mist cooling is carried out, the quenching temperature is controlled at 500-530℃, the holding time is 10-15min, and the cooling rate is 20-25℃ / s. This method can effectively fix the supersaturated solid solution inside the profile, avoid generating excessive internal stress, and prevent deformation or cracking.

[0025] VI. Aging treatment: The quenched aluminum profiles are sent into an electric heating aging furnace and heated to 120–140℃ at a heating rate of 3–5℃ / min. The holding time is 4–6 hours. During this period, the furnace temperature is calibrated every 1 hour by a PID temperature controller, and the temperature fluctuation is controlled within ±2℃. Aging treatment allows for the uniform precipitation of reinforcing phases such as Mg2Si, significantly improving the mechanical properties of the profile. Ultimately, complex cross-section recycled aluminum profiles with tensile strength ≥280MPa, yield strength ≥250MPa, elongation ≥8%, and hardness ≥85HB are obtained.

[0026] Meanwhile, an ultrasonic vibration shaping section is added between the quenching outlet and the aging furnace inlet. When the profile surface temperature is still maintained at 180–220℃, an ultrasonic vibration with a frequency of 20–40kHz and an amplitude of 10–30μm is applied to the key cavity or thin-walled part through a multi-point pneumatic clamping device in conjunction with an ultrasonic transducer for 30–60s. The ultrasonic vibration is coupled with the residual temperature to promote micro-slip of grain boundaries and release internal stress. At the same time, a slight shaping force of no more than 5MPa is applied to correct the micron-level warping or twisting caused by uneven cooling. Compared with traditional natural cooling, the overall curvature of the profile is reduced by more than 40%, the subsequent machining allowance can be reduced by 0.05–0.1mm, and the yield is increased by 3–5%.

[0027] This invention utilizes a combination of manual and mechanical sorting methods, along with multiple impurity removal technologies such as magnetic separation, eddy current separation, and wind separation, to effectively remove various impurities from waste aluminum. After standardized processing such as crushing, alkaline washing, and drying, it not only achieves efficient recycling of recycled aluminum resources and reduces resource waste, but also provides a clean and uniform raw material base for subsequent processes. This avoids profile defects caused by impurity residues from the source, thereby improving raw material utilization and product qualification rate.

[0028] This invention relies on the precise addition of intermediate alloys and the uniform mixing process of a double-cone mixer. Combined with the "extrusion-feedback-batching" closed-loop control system constructed by laser-induced breakdown spectroscopy online detection and PLC batching system, it can monitor the profile composition in real time and dynamically fine-tune the batching ratio. Compared with the traditional open-loop batching mode, it significantly reduces the standard deviation of composition, making the alloy element distribution of each profile more uniform. This effectively ensures the consistency and stability of product composition, lays a solid foundation for the stability of subsequent mechanical properties, and meets the stringent requirements of high-end structural components for the accuracy of material composition.

[0029] During the extrusion molding process of this invention, the nitrogen protective atmosphere of the regenerative continuous heating furnace is used to avoid oxidation of the molten material and burning of alloy elements. Through the design of the trumpet-shaped flow guide zone of the gradient extrusion die and the control of the vacuum environment of the barrel, the melt is ensured to fill the cavity smoothly, reducing the entrapment of air bubbles and significantly improving the dimensional accuracy and surface finish of the profile. This effectively solves the problems of uneven filling and large dimensional deviation that are easy to occur in the molding process of complex cross-section profiles, and at the same time realizes high-precision molding of complex structures such as multi-cavity and irregular curved surfaces.

[0030] This invention's online air-fog quenching process can quickly fix the supersaturated solid solution inside the profile, avoiding deformation and cracking caused by excessive internal stress. The low-temperature aging treatment, through precise temperature control, promotes the uniform precipitation of strengthening phases, significantly improving the profile's tensile strength, yield strength, elongation, and hardness, meeting the load-bearing and impact resistance requirements of structural components. Furthermore, the ultrasonic vibration shaping technology introduced during the residual heat stage of quenching, combined with multi-point pneumatic clamping, can efficiently release internal stress, correct micron-level warping or twisting defects, reduce subsequent machining allowances, further improve yield, and reduce material waste and processing costs.

[0031] In addition, the extrusion method for recycled aluminum profiles with complex cross-sections includes the following embodiments: Example 1

[0032] This embodiment targets recycled aluminum profiles with complex cross-sections and multi-cavity structures (maximum wall thickness 10mm, minimum wall thickness 2mm, wall thickness ratio 5:1), and adopts the following operating steps: Pre-treatment of recycled aluminum raw materials: A combination of manual and mechanical sorting is used to process the recycled scrap aluminum from doors and windows. Obvious plastic insulation strips and iron connectors are manually removed. A magnetic separator generates a strong magnetic field to adsorb residual ferrous impurities. An eddy current separator separates any non-ferrous metals that may be mixed in, and a wind-powered separator removes light debris, further improving the purity of the scrap aluminum. The processed scrap aluminum is then fed into a jaw crusher (800 r / min) to crush into 30mm particles. During crushing, a circulating cooling water system is activated to continuously spray 20℃ cooling water to prevent oxidation due to friction. Next, the aluminum particles are sent to an alkaline washing tank equipped with heating and circulation devices, where they are washed with a 5% sodium hydroxide solution at 50℃ for 20 minutes to thoroughly remove surface oil and oxide film. Finally, the aluminum particles are rinsed with clean water until neutral using a spray cleaner, and then sent to a hot air circulating dryer to dry at 120℃ for 3 hours to ensure the aluminum particles are dry and clean, preventing bubbles or defects in subsequent processes.

[0033] Composition Adjustment: Using an automatic weighing and adding device, Al-20Si, Al-10Mg, Al-30Cu, and Al-15Mn master alloys are precisely added to the dried aluminum granules, so that the final alloy element mass ratio reaches Si 0.8%, Mg 0.4%, Cu 0.1%, Mn 0.05%, with the balance being Al. Then, the aluminum granules and master alloys are fed into a double cone mixer and mixed at a speed of 300 r / min for 15 min to ensure uniform distribution of alloy elements and form a mixed raw material, laying the foundation for improving the microstructure consistency and mechanical properties of the subsequent molding material.

[0034] Heating and melting: The mixed raw materials are put into a regenerative continuous heating furnace. Nitrogen gas with a purity of 99.99% is introduced into the furnace through a nitrogen generator to control the oxygen content in the furnace to 0.01% and create an inert protective atmosphere. The temperature is raised to 580℃ at a heating rate of 5℃ / min and held for 3 hours to ensure that the mixed raw materials are fully melted and the composition is uniform, avoiding oxidation and loss of alloying elements, and forming a stable molten aluminum material.

[0035] Extrusion Molding: Molten aluminum is injected into the extruder through a tilting, insulated flow channel. A hydraulic plunger pushes the molten aluminum into an electrically heated barrel preheated to 550°C at an initial velocity of 0.2 m / s. The flow divider cone and perforated plate at the end of the barrel evenly distribute the melt and filter out inclusions. The plunger then continues to advance, causing the melt to flow laminarly into a gradient extrusion die made of H13 hot work die steel (0.1 mm nitrided layer, 900 HV hardness, 30° core cone angle, and 5 mm die radius). The funnel-shaped guide zone at the die inlet guides the melt to smoothly transition into the cavity formed by the core and die sleeve. The filling is completed in a 400°C environment maintained by the die heating furnace. Finally, the molten aluminum is continuously extruded from the die to form a multi-cavity aluminum profile with a complex cross-section. The entire extrusion process is carried out under a 0.08 MPa barrel vacuum maintained by a vacuum pump to avoid air bubble entrapment and ensure that the profile dimensional accuracy reaches ±0.1 mm and the surface roughness Ra1.6 μm. Meanwhile, the laser-induced breakdown spectroscopy (LIBS) online composition probe installed at the extruder outlet performs a rapid scan of the profile surface every 30 seconds, providing feedback on the measured values ​​of Si, Mg, Cu, and Mn within 30 seconds. The data is transmitted back to the front-end PLC batching system in real time via industrial Ethernet. The deviation is calculated by comparing it with the target composition range. The PLC automatically fine-tunes the amount of intermediate alloy added in the next batch based on the deviation, with an adjustment step size not exceeding 0.02%, forming a closed-loop control of "extrusion-feedback-batching". When the results of three consecutive tests are all within ±0.05% of the target median, the system determines that the batch is qualified and records a traceability code through an inkjet printer, realizing traceability of the composition of a single profile.

[0036] Online quenching: The extruded aluminum profile is immediately sent to the air-mist quenching device. The compressed air-water mixture with a water mass ratio of 10% is provided by an air compressor and a high-pressure water pump as the cooling medium. The temperature is held at 500℃ for 15 minutes, and the cooling rate is controlled at 20℃ / s. This process can effectively fix the supersaturated solid solution inside the profile, avoid the generation of excessive internal stress, and prevent deformation or cracking.

[0037] Aging Treatment: The quenched profiles are placed in an electrically heated aging furnace and heated to 120°C at a heating rate of 3°C / min, and held for 6 hours. During this period, the furnace temperature is calibrated every 1 hour using a PID temperature controller to ensure that the temperature fluctuation is controlled within ±2°C. The aging treatment promotes the uniform precipitation of strengthening phases such as Mg2Si, significantly improving the mechanical properties of the profiles. At the same time, an ultrasonic vibration shaping section is added between the quenching outlet and the aging furnace inlet. When the surface temperature of the profile is maintained at 180-200°C, an ultrasonic vibration with a frequency of 20kHz and an amplitude of 10μm is applied to the key parts of the multi-cavity structure using a multi-point pneumatic clamping device and an ultrasonic transducer for 60 seconds. The ultrasonic vibration is coupled with the residual temperature to promote micro-slip of the grain boundaries and release internal stress. At the same time, a slight shaping force of no more than 5MPa is applied to correct micron-level warping or twisting caused by uneven cooling. Final testing showed that the profile had a tensile strength of 280MPa, a yield strength of 250MPa, an elongation of 8%, and a hardness of 85HB. The overall curvature was reduced by more than 40% compared to traditional processes, and the subsequent machining allowance could be reduced by 0.05mm.

[0038] Example 2 This embodiment targets recycled aluminum profiles with complex cross-sections and multi-cavity structures (maximum wall thickness 9mm, minimum wall thickness 2.25mm, wall thickness ratio 4:1), and adopts the following operating steps: Pre-treatment of recycled aluminum raw materials: The recycled waste automotive aluminum parts are sorted, and rubber seals and copper wires are manually removed. Then, they are sequentially passed through a magnetic separator, an eddy current separator, and an air separator to complete multiple impurity removal processes, accurately removing ferrous metals, non-ferrous impurities, and light debris. Subsequently, they are fed into a jaw crusher (850 r / min) to be crushed into aluminum particles with a particle size of 35 mm. During crushing, the circulating cooling water system is turned on to spray 22°C cooling water to cool down the aluminum particles and prevent oxidation. The aluminum particles are then sent to an alkaline washing tank and cleaned with a 6% sodium hydroxide solution at 52°C for 18 minutes to remove surface oil and oxide film. They are then rinsed with a spray cleaner until neutral and finally sent to a hot air circulating dryer to dry at 130°C for 2.5 hours to ensure that the aluminum particles are dry and free of impurities.

[0039] Composition adjustment: Al-20Si, Al-10Mg, Al-30Cu, and Al-15Mn master alloys are added to aluminum granules using an automatic weighing and feeding device to achieve a mass ratio of Si 0.9%, Mg 0.45%, Cu 0.12%, Mn 0.06%, with the balance being Al. The mixture is then fed into a double cone mixer and mixed at 300 r / min for 18 min to ensure uniform distribution of alloy elements and form a high-quality mixed raw material.

[0040] Heating and melting: The mixed raw materials are fed into a regenerative continuous heating furnace, and nitrogen gas with a purity of 99.99% is introduced. The oxygen content in the furnace is controlled at 0.009%. The temperature is increased to 590℃ at a heating rate of 6℃ / min and held for 2.8h to ensure that the raw materials are fully melted and the composition is uniform, avoiding oxidation and loss of alloying elements, and obtaining stable molten aluminum.

[0041] Extrusion molding: Molten aluminum is injected into the extruder through a tilting insulated flow channel. A hydraulic plunger pushes it into an electrically heated barrel preheated to 560°C at an initial velocity of 0.25 m / s. The flow divider cone and perforated plate at the end of the barrel achieve uniform flow of the melt and filtration of impurities. The melt then enters the H13 hot work die steel gradient extrusion die (0.12 mm nitrided layer, hardness 920 HV, die core cone angle 33°, die opening radius 6 mm) under a laminar flow at a pressure of 20 MPa and a velocity of 4 mm / s. The funnel-shaped guide zone at the die inlet guides the melt to smoothly fill the cavity formed by the die core and die sleeve. The die heating furnace maintains a 410°C environment to ensure molding quality. The extrusion process is carried out under a barrel vacuum of 0.082 MPa to avoid air bubble entrapment and ensure the profile dimensional accuracy of ±0.1 mm and surface roughness Ra1.5 μm. Meanwhile, the laser-induced breakdown spectroscopy (LIBS) online composition probe scans the surface of the profile every 30 seconds and feeds back the composition data to the PLC batching system in real time. The system automatically fine-tunes the amount of intermediate alloy added in the next batch based on the deviation, with an adjustment step of no more than 0.02%. After three consecutive qualified tests, a traceability code is printed to achieve composition traceability.

[0042] Online quenching: The extruded profiles immediately enter the air-mist quenching device, and the cooling medium is a compressed air-water mixture with a water mass ratio of 11%. The temperature is maintained at 510℃ for 14 minutes, and the cooling rate is controlled at 21℃ / s to effectively fix the supersaturated solid solution and prevent the profiles from deforming and cracking.

[0043] Aging Treatment: The quenched profiles were placed in an electrically heated aging furnace and heated to 125℃ at a heating rate of 4℃ / min, held for 5.5 hours, and the PID temperature controller was calibrated every hour, with temperature fluctuations within ±2℃. During the aging process, ultrasonic vibration shaping was initiated during the residual heat stage of quenching (profile surface temperature 200-220℃). Using a multi-point pneumatic clamping device in conjunction with an ultrasonic transducer, ultrasonic vibration at a frequency of 30kHz and an amplitude of 20μm was applied to the thin-walled sections of the multi-cavity profiles for 45 seconds to release internal stress and correct morphological defects. Final test results showed that the profiles had a tensile strength of 285MPa, a yield strength of 255MPa, an elongation of 8.2%, a hardness of 86HB, a reduction in overall curvature of over 40%, and a reduction in subsequent machining allowance of 0.07mm, meeting the requirements for high-precision machining.

[0044] Example 3 This embodiment targets recycled aluminum profiles with complex cross-sections and multi-cavity structures (maximum wall thickness 8mm, minimum wall thickness 2.67mm, wall thickness ratio 3:1), and adopts the following operating steps: Pre-treatment of recycled aluminum raw materials: Waste aluminum from recycled beverage cans is first removed by specialized equipment to remove the surface coating, then manually sorted for preliminary impurity removal. Subsequently, it passes through a magnetic separator, eddy current separator, and air separator to thoroughly remove metallic impurities and lightweight debris. The treated waste aluminum is then fed into a jaw crusher (900 r / min) to crush into aluminum particles with a diameter of 40 mm. During crushing, a circulating cooling water system sprays 23°C cooling water to lower the temperature and prevent oxidation of the aluminum particles. The aluminum particles are then sent to an alkaline washing tank and cleaned with a 7% sodium hydroxide solution at 54°C for 16 minutes to remove surface oil and oxide film. After being rinsed to neutral by a spray cleaning machine, the particles are sent to a hot air circulating dryer and dried at 140°C for 2.2 hours to ensure the aluminum particles are dry and clean.

[0045] Composition adjustment: Al-20Si, Al-10Mg, Al-30Cu, and Al-15Mn master alloys are added to aluminum granules using an automatic weighing and feeding device to achieve a mass ratio of Si 1.0%, Mg 0.5%, Cu 0.15%, Mn 0.07%, with the balance being Al. The mixture is then fed into a double cone mixer and mixed at 300 r / min for 20 min to ensure uniform distribution of alloy elements and improve the quality of the mixed raw materials.

[0046] Heating and melting: The mixed raw materials are put into a regenerative continuous heating furnace, and nitrogen gas with a purity of 99.99% is introduced to create a protective atmosphere. The oxygen content in the furnace is controlled to be ≤0.01%. The furnace is heated to 600℃ at a heating rate of 7℃ / min and held for 2.5h to ensure that the raw materials are fully melted and the composition is uniform, avoiding oxidation and loss of alloying elements, and obtaining stable molten aluminum.

[0047] Extrusion molding: Molten aluminum is injected into the extruder through a tilting insulated flow channel. A hydraulic plunger pushes the material into an electrically heated barrel preheated to 565°C at an initial velocity of 0.3 m / s. The flow divider cone and perforated plate at the end of the barrel achieve melt diversion and impurity filtration. The melt enters the H13 hot work die steel gradient extrusion die (0.14 mm nitrided layer, hardness 930 HV, die core cone angle 36°, die opening radius 6.5 mm) in a laminar flow under a pressure of 21 MPa and a velocity of 5 mm / s. The horn-shaped guide zone at the die inlet guides the melt to fill the cavity smoothly. The die heating furnace maintains an environment of 420°C. The extrusion process is carried out under a barrel vacuum of 0.084 MPa to avoid air bubble entrapment and ensure the dimensional accuracy of the profile is ±0.09 mm and the surface roughness is Ra1.4 μm. Meanwhile, the laser-induced breakdown spectroscopy (LIBS) online component detection system monitors the components in real time, and the PLC batching system automatically fine-tunes the amount of intermediate alloy added based on the deviation, forming a closed-loop control; qualified batches are marked with traceability codes to achieve component traceability.

[0048] Online quenching: The extruded profile is immediately sent into the air-mist quenching device. The cooling medium is a compressed air-water mixture with a water mass ratio of 12%. It is held at 515℃ for 13 minutes, and the cooling rate is controlled at 22℃ / s to effectively fix the supersaturated solid solution and avoid excessive internal stress.

[0049] Aging Treatment: The quenched profiles are placed in an electrically heated aging furnace and heated to 130℃ at a heating rate of 4℃ / min, held for 5 hours, and the furnace temperature is calibrated every 1 hour with a temperature fluctuation of ±2℃. During the residual heat stage of quenching (profile surface temperature 190-210℃), ultrasonic vibration with a frequency of 40kHz and an amplitude of 30μm is applied to the key cavities of the profile for 30 seconds, combined with multi-point pneumatic clamping to complete the shaping. Final testing shows that the profile has a tensile strength of 290MPa, a yield strength of 258MPa, an elongation of 8.3%, and a hardness of 87HB. The overall curvature is reduced by more than 40% compared to the traditional process, the subsequent machining allowance can be reduced by 0.1mm, and the yield rate is increased by 3-5%.

[0050] Example 4 This embodiment targets recycled aluminum profiles with complex cross-sections and irregular curved surfaces (maximum wall thickness 10mm, minimum wall thickness 2.5mm, wall thickness ratio 4:1). The specific steps are as follows: Pre-treatment of recycled aluminum raw materials: The recycled waste aluminum casings of electronic appliances are sorted, and plastic panels and circuit board residues attached to the surface are manually removed. Then, the raw materials are subjected to multiple impurity removal processes, including magnetic separator (strong magnetic field adsorption of residual iron filings), eddy current separator (separation of non-ferrous metal impurities), and air separator (removal of lightweight plastic debris), to improve the purity of the raw materials. The processed waste aluminum is then fed into a jaw crusher (950 r / min) and crushed into aluminum particles with a particle size of 45 mm. During the crushing process, a circulating cooling water system is activated to continuously spray 24°C cooling water to prevent the aluminum particles from oxidizing due to friction. The aluminum particles are then sent to an alkaline washing tank equipped with heating and circulation devices, and washed with an 8% sodium hydroxide solution at 56°C for 14 minutes to thoroughly remove surface oil and oxide film. The particles are then rinsed with clean water until neutral by a spray cleaning machine, and finally sent to a hot air circulating dryer to dry at 145°C for 2.1 hours to ensure that the aluminum particles are dry and free of moisture, providing clean raw materials for subsequent processes.

[0051] Composition Adjustment: Using an automatic weighing and adding device, Al-20Si, Al-10Mg, Al-30Cu, and Al-15Mn master alloys are precisely added to the dried aluminum granules, so that the final alloy element mass ratio reaches Si 1.1%, Mg 0.55%, Cu 0.18%, Mn 0.08%, with the balance being Al. The aluminum granules and master alloys are then fed into a double cone mixer and mixed at a speed of 300 r / min for 18 min to ensure uniform distribution of alloy elements and form a stable mixed raw material, laying the foundation for improving the consistency of profile structure and mechanical properties.

[0052] Heating and melting: The mixed raw materials are put into a regenerative continuous heating furnace. Nitrogen gas with a purity of 99.99% is introduced into the furnace through a nitrogen generator to control the oxygen content in the furnace to 0.008% and create an inert protective atmosphere. The furnace is heated to 610℃ at a heating rate of 8℃ / min and held at that temperature for 2.2h. During this period, the temperature and atmosphere in the furnace are monitored regularly to ensure that the mixed raw materials are fully melted and have a uniform composition, avoiding oxidation and loss of alloying elements, and forming a stable molten aluminum material.

[0053] Extrusion Molding: Molten aluminum is injected into the extruder through a tilting, insulated flow channel. A hydraulic plunger pushes the molten aluminum into a preheated, electrically heated barrel at an initial velocity of 0.35 m / s. A flow divider cone and perforated plate at the end of the barrel uniformly distribute the melt and filter out minor inclusions. The plunger continues to advance, causing the melt to flow laminarly into a gradient extrusion die made of H13 hot-work die steel (0.16 mm nitrided layer, 940 HV hardness, 39° core cone angle). (7mm rounded corner at the die opening); the trumpet-shaped guide area at the die inlet is adapted to the requirements of irregular curved surface structures, guiding the melt to smoothly transition to the cavity formed by the die core and die sleeve, completing the filling in an environment of 430℃ maintained by the die heating furnace, and finally continuously extruding from the die opening to form an aluminum profile with complex cross-section of irregular curved surface; the entire extrusion process is carried out under a barrel vacuum of 0.086MPa maintained by a vacuum pump to avoid air bubble entrapment and ensure that the surface dimensional accuracy reaches ±0.09mm and the surface roughness Ra1.3μm. Meanwhile, the laser-induced breakdown spectroscopy (LIBS) online composition probe installed at the extruder outlet performs a rapid scan of the profile surface every 30 seconds, providing feedback on the measured values ​​of Si, Mg, Cu, and Mn within 30 seconds. The data is transmitted back to the front-end PLC batching system in real time via industrial Ethernet. The deviation is calculated by comparing it with the target composition range. The PLC automatically fine-tunes the amount of intermediate alloy added in the next batch based on the deviation, with an adjustment step size not exceeding 0.02%, forming a closed-loop control of "extrusion-feedback-batching". When the results of three consecutive tests are all within ±0.05% of the target median, the system determines that the batch is qualified and records a traceability code through an inkjet printer, realizing traceability of the composition of a single profile.

[0054] Online quenching: The extruded aluminum profile is immediately sent into the air-mist quenching device. A compressed air-water mixture with a water mass ratio of 13% is provided by an air compressor and a high-pressure water pump as the cooling medium. The profile is held at 520℃ for 12 minutes, and the cooling rate is controlled at 23℃ / s. This process can quickly fix the supersaturated solid solution inside the profile and avoid deformation or cracking of irregular curved surfaces due to uneven stress distribution.

[0055] Aging Treatment: The quenched profiles are placed in an electrically heated aging furnace and heated to 135℃ at a heating rate of 5℃ / min, and held for 4.5 hours. During this period, the furnace temperature is calibrated every 1 hour using a PID temperature controller to ensure that the temperature fluctuation is controlled within ±2℃. The aging treatment promotes the uniform precipitation of strengthening phases such as Mg2Si, significantly improving the mechanical properties of the profiles. At the same time, an ultrasonic vibration shaping section is added between the quenching outlet and the aging furnace inlet. Utilizing the residual heat of the irregular curved surface (surface temperature 200-220℃), the key points of the profile surface are precisely fixed by a multi-point pneumatic clamping device. Ultrasonic vibration with a frequency of 35kHz and an amplitude of 25μm is applied by an ultrasonic transducer for 40 seconds. The ultrasonic vibration and residual temperature couple to promote micro-slip of grain boundaries to release internal stress. At the same time, a slight shaping force of no more than 5MPa is applied to correct micron-level warping or twisting of the curved surface caused by uneven cooling. Final testing showed that the profile had a tensile strength of 295MPa, a yield strength of 260MPa, an elongation of 8.5%, and a hardness of 88HB. The surface form and position tolerance was reduced by more than 40% compared with the traditional process, and the subsequent machining allowance could be reduced by 0.08mm.

[0056] Example 5 This embodiment targets recycled aluminum profiles with complex cross-sections and irregular curved surfaces (maximum wall thickness 10mm, minimum wall thickness 2mm, wall thickness ratio 5:1). The specific steps are as follows: Pre-treatment of recycled aluminum raw materials: The recycled waste aluminum formwork is sorted, and the cement residue attached to the surface is manually removed. After the steel connectors are removed, the aluminum is passed through a magnetic separator (to remove ferrous impurities), an eddy current separator (to separate non-ferrous metals), and an air separator (to remove dust and light debris) for deep impurity removal. The processed waste aluminum is then fed into a jaw crusher (1000 r / min) and crushed into aluminum particles with a particle size of 50 mm. During the crushing process, a circulating cooling water system continuously sprays 25°C cooling water to prevent the aluminum particles from oxidizing. The aluminum particles are then sent to an alkaline washing tank and washed with an 8% sodium hydroxide solution at 58°C for 15 minutes to remove surface oil and oxide film. After being rinsed to neutral by a spray cleaning machine, the aluminum particles are sent to a hot air circulating dryer and dried at 150°C for 2 hours to ensure that the aluminum particles are dry, clean, and free of impurities and moisture residue.

[0057] Composition adjustment: Al-20Si, Al-10Mg, Al-30Cu, and Al-15Mn master alloys are added to aluminum granules using an automatic weighing and feeding device to achieve a mass ratio of Si 1.2%, Mg 0.6%, Cu 0.2%, Mn 0.1%, with the balance being Al. The mixture is then fed into a double cone mixer and mixed at 300 r / min for 20 min to ensure uniform distribution of alloy elements and form a high-quality mixed raw material.

[0058] Heating and melting: The mixed raw materials are put into a regenerative continuous heating furnace, and nitrogen gas with a purity of 99.99% is introduced. The oxygen content in the furnace is controlled to be ≤0.01%. The furnace is heated to 620℃ at a heating rate of 8℃ / min and held for 2 hours. During this period, the temperature and atmosphere stability in the furnace are monitored to ensure that the raw materials are fully melted and the composition is uniform, avoiding oxidation and loss of alloying elements, and obtaining stable molten aluminum.

[0059] Extrusion molding: Molten aluminum is injected into the extruder through a tilting insulated flow channel. A hydraulic plunger pushes it into an electrically heated barrel preheated to 580°C at an initial velocity of 0.4 m / s. The flow divider cone and perforated plate at the end of the barrel achieve uniform flow of the melt and filtration of impurities. The melt then enters the H13 hot work die steel gradient extrusion die (0.2 mm nitrided layer, hardness 950 HV, die core cone angle 45°, die orifice radius 8 mm) under a laminar flow at a pressure of 25 MPa and a velocity of 8 mm / s. The trumpet-shaped guide zone at the die inlet is designed for thick-walled differential curved surfaces to guide the melt to fill the cavity smoothly. The die heating furnace maintains a 450°C environment to ensure full curvature of the curved surface. The extrusion process is carried out under a 0.09 MPa barrel vacuum to avoid air bubble entrapment and ensure a surface dimensional accuracy of ±0.08 mm and a surface roughness of Ra1.2 μm. Meanwhile, the laser-induced breakdown spectroscopy (LIBS) online composition probe scans the surface of the profile every 30 seconds and feeds back the composition data to the PLC batching system in real time. The system automatically fine-tunes the amount of intermediate alloy added in the next batch based on the deviation, with an adjustment step of no more than 0.02%. After three consecutive qualified tests, a traceability code is printed to achieve composition traceability.

[0060] Online quenching: The extruded profiles immediately enter the air-mist quenching device. The cooling medium is a compressed air-water mixture with a water mass ratio of 15%. The profiles are held at 530℃ for 10 minutes with a cooling rate controlled at 25℃ / s to quickly fix the supersaturated solid solution and prevent cracking or deformation of irregular curved surfaces due to differences in wall thickness.

[0061] Aging Treatment: The quenched profiles were placed in an electrically heated aging furnace and heated to 140℃ at a heating rate of 5℃ / min, held for 4 hours, and the furnace temperature was calibrated every 1 hour by a PID temperature controller, with temperature fluctuations within ±2℃. During the aging process, in the residual heat stage of quenching (profile surface temperature 180-200℃), the profiles were fixed using a multi-point pneumatic clamping device adapted to irregular curved surfaces, and ultrasonic vibration at a frequency of 40kHz and an amplitude of 30μm was applied for 35 seconds using an ultrasonic transducer to release internal stress and correct surface shape and position defects. The final test results showed that the profiles had a tensile strength of 300MPa, a yield strength of 270MPa, an elongation of 9%, a hardness of 90HB, and a reduction in surface shape and position tolerances of more than 40%, resulting in a reduction of 0.1mm in subsequent machining allowances, meeting the precision requirements of high-end irregular structural parts.

[0062] Example 6 This embodiment targets recycled aluminum profiles with complex cross-sections and irregular curved surfaces (maximum wall thickness 8.5mm, minimum wall thickness 2.125mm, wall thickness ratio 4:1). The specific steps are as follows: Pre-treatment of recycled aluminum raw materials: The recycled waste aerospace aluminum scraps (meeting civilian recycling standards) are sorted, and rare metal impurities such as titanium alloys are manually removed. Then, they are sequentially passed through a magnetic separator (adsorbing ferrous impurities), an eddy current separator (separating non-ferrous metals), and an air separator (removing light debris) to complete the impurity removal. The processed waste aluminum is then fed into a jaw crusher (820 r / min) and crushed into aluminum particles with a particle size of 32 mm. During crushing, a circulating cooling water system sprays 21°C cooling water to cool the aluminum particles and prevent oxidation. The aluminum particles are then sent to an alkaline washing tank and washed with a 5.5% sodium hydroxide solution at 51°C for 19 minutes to remove surface oil and oxide film. After being rinsed to neutral by a spray cleaning machine, the particles are sent to a hot air circulating dryer and dried at 125°C for 2.8 hours to ensure that the aluminum particles are dry and clean.

[0063] Composition adjustment: Al-20Si, Al-10Mg, Al-30Cu, and Al-15Mn master alloys are added to aluminum granules using an automatic weighing and feeding device to achieve a mass ratio of Si 0.85%, Mg 0.42%, Cu 0.11%, Mn 0.055%, with the balance being Al. The mixture is then fed into a double cone mixer and mixed at 300 r / min for 16 min to ensure uniform distribution of alloy elements and form a stable mixed raw material.

[0064] Heating and melting: The mixed raw materials are put into a regenerative continuous heating furnace, and nitrogen gas with a purity of 99.99% is introduced. The oxygen content in the furnace is controlled at 0.0095%. The temperature is raised to 585℃ at a heating rate of 5.5℃ / min and held for 2.9h. During this period, the temperature uniformity in the furnace is monitored to ensure that the raw materials are fully melted and the composition is uniform, avoiding oxidation and loss of alloying elements, and obtaining stable molten aluminum.

[0065] Extrusion molding: Molten aluminum is injected into the extruder through a tilting insulated flow channel. The hydraulic plunger pushes the material into the preheated 555℃ electrically heated barrel at an initial velocity of 0.22m / s. The flow divider cone and perforated plate at the end of the barrel achieve melt diversion and impurity filtration. The melt enters the H13 hot work die steel gradient extrusion die (0.11mm nitrided layer, 905HV hardness, 32° core cone angle, and 5.5mm die radius) in a laminar flow under a pressure of 19MPa and a velocity of 3.5mm / s. The horn-shaped guide zone at the die inlet guides the melt to smoothly fill the irregular curved cavity. The die heating furnace maintains an environment of 405℃. The extrusion process is carried out under a 0.081MPa barrel vacuum to avoid air bubble entrapment and ensure the surface dimensional accuracy of ±0.095mm and surface roughness Ra1.55μm. Meanwhile, the laser-induced breakdown spectroscopy (LIBS) online component detection system monitors the components in real time, and the PLC batching system automatically fine-tunes the amount of intermediate alloy added based on the deviation, forming a closed-loop control; qualified batches are marked with traceability codes to achieve component traceability.

[0066] Online quenching: The extruded profile is immediately sent into the air-mist quenching device. The cooling medium is a compressed air-water mixture with a water mass ratio of 10.5%. The profile is held at 505℃ for 14.5 minutes with a cooling rate of 20.5℃ / s to effectively fix the supersaturated solid solution and prevent the profile from deforming and cracking.

[0067] Aging Treatment: The quenched profiles are placed in an electrically heated aging furnace and heated to 122℃ at a heating rate of 3.5℃ / min, held for 5.8 hours, and the PID temperature controller is calibrated every 1 hour, with temperature fluctuations within ±2℃. During the residual heat stage of quenching (profile surface temperature 190-210℃), ultrasonic vibration at a frequency of 25kHz and an amplitude of 15μm is applied to key parts of the irregular curved surface for 50 seconds, combined with multi-point pneumatic clamping to complete the shaping. Final testing shows that the profile has a tensile strength of 282MPa, a yield strength of 252MPa, an elongation of 8.1%, and a hardness of 85.5HB. The surface form and position tolerances are reduced by more than 40% compared to traditional processes, the subsequent machining allowance can be reduced by 0.06mm, and the yield rate is increased by 3-5%.

[0068] Example 7 This embodiment is for recycled aluminum profiles with complex cross-sections and irregular curved surfaces (maximum wall thickness 7.5mm, minimum wall thickness 2.5mm, wall thickness ratio 3:1). The specific operating steps are as follows: Pre-treatment of recycled aluminum raw materials: The recycled waste aluminum radiator profiles are sorted, and after manually peeling off the plastic fins attached to the surface, they are sequentially passed through a magnetic separator (using a strong magnetic field to adsorb hidden ferrous impurities), an eddy current separator (using the eddy current effect to separate non-ferrous metals such as copper and zinc), and an air separator (using airflow differences to remove dust and light debris), achieving multiple deep impurity removal processes. The processed waste aluminum is then fed into a jaw crusher (880 r / min) and crushed into aluminum particles with a diameter of 38 mm. Circulating cooling is activated during the crushing process. The water system continuously sprays 23°C cooling water to prevent the aluminum particles from oxidizing due to frictional heat. The aluminum particles are then sent to an alkaline washing tank equipped with heating and circulating stirring devices, where they are cleaned with a 6.5% sodium hydroxide solution at 53°C for 17 minutes to thoroughly remove surface oil and oxide film. The aluminum particles are then rinsed with clean water until the pH is neutral using a spray cleaning machine, and finally sent to a hot air circulating dryer to dry at 135°C for 2.4 hours to ensure that the aluminum particles are dry and free of moisture and impurities, providing clean raw materials for subsequent processes.

[0069] Composition Adjustment: Al-20Si, Al-10Mg, Al-30Cu, and Al-15Mn master alloys are precisely added to the dried aluminum granules using an automatic weighing and adding device, so that the final alloy element mass ratio reaches 0.95% Si, 0.48% Mg, 0.14% Cu, and 0.065% Mn, with the balance being Al. The aluminum granules and master alloys are then fed into a double-cone mixer and mixed at a speed of 300 r / min for 18 min. Utilizing the tumbling mixing characteristics of the double-cone structure, the alloy elements are ensured to be evenly distributed in the aluminum granules, forming a stable mixed raw material, which lays the foundation for improving the consistency of the profile structure and mechanical properties.

[0070] Heating and melting: The mixed raw materials are put into a regenerative continuous heating furnace. Nitrogen gas with a purity of 99.99% is introduced into the furnace through a nitrogen generator to control the oxygen content in the furnace to ≤0.01% and create an inert protective atmosphere to isolate air. The furnace is slowly heated to 595℃ at a heating rate of 6.5℃ / min and held at that temperature for 2.6h. During this period, the temperature distribution is monitored in real time by a temperature sensor in the furnace to ensure that the mixed raw materials are fully melted and the composition is uniform, avoiding oxidation reaction and loss of alloying elements, and finally forming a stable molten aluminum material.

[0071] Extrusion Molding: Molten aluminum is injected into the extruder through a tilting, insulated flow channel (maintaining temperature and melt flowability). A hydraulic plunger pushes it into an electrically heated barrel preheated to 562°C by an initial velocity of 0.32 m / s. A flow divider cone and a perforated plate are installed at the end of the barrel. The flow divider cone ensures uniform melt distribution, and the perforated plate filters out any minute impurities that may remain in the molten material. The plunger continues to advance, causing the melt to flow in a laminar state at a pressure of 20.5 MPa and a velocity of 4.5 mm / s, entering a gradient extrusion die made of H13 hot work die steel (nitrided layer thickness 0). (13mm diameter, surface hardness 925HV, core cone angle 35°, die opening radius 6.2mm); the horn-shaped guide zone at the die inlet is designed to accommodate the filling requirements of irregular curved surfaces, guiding the melt smoothly to the cavity formed by the core and die sleeve. The die heating furnace maintains a 415℃ environment to ensure that the melt fully fills the cavity. The entire extrusion process is carried out in a 0.083MPa barrel vacuum environment maintained by a vacuum pump, effectively avoiding air bubble entrapment and ensuring that the profile surface dimensional accuracy reaches ±0.09mm and the surface roughness Ra1.45μm. Meanwhile, an online composition probe for laser-induced breakdown spectroscopy (LIBS) is installed at the extruder outlet. It performs a rapid scan of the profile surface every 30 seconds and provides feedback on the measured values ​​of Si, Mg, Cu, and Mn elements within 30 seconds. The data is transmitted back to the front-end PLC batching system in real time via industrial Ethernet. The deviation is calculated by comparing the data with the target composition range. The PLC system automatically fine-tunes the amount of intermediate alloy added in the next batch based on the deviation, with an adjustment step size not exceeding 0.02%, forming a closed-loop control of "extrusion-feedback-batching". When the results of three consecutive tests are all within ±0.05% of the target median, the system determines that the batch is qualified and prints a traceability code on the profile surface using an inkjet printer, realizing traceability of the composition of a single profile.

[0072] Online quenching: The extruded irregular curved aluminum profile is immediately sent to the air-mist quenching device. The air compressor and high-pressure water pump work together to provide a compressed air-water mixture with a water mass ratio of 11.5% as the cooling medium. The profile is held at 512℃ for 13.5 minutes, and the cooling rate is controlled at 21.5℃ / s. The supersaturated solid solution inside the profile is fixed by rapid cooling, which avoids deformation or cracking of the irregular curved surface due to uneven stress distribution.

[0073] Aging Treatment: The quenched profiles are placed in an electrically heated aging furnace and heated to 128℃ at a heating rate of 4.2℃ / min, and held for 5.2 hours. During this period, the furnace temperature is calibrated every 1 hour using a PID temperature controller to ensure that the temperature fluctuation is controlled within ±2℃. This low-temperature aging treatment promotes the uniform precipitation of strengthening phases such as Mg2Si inside the profile, significantly improving its mechanical properties. Simultaneously, an ultrasonic vibration shaping section is added between the quenching outlet and the aging furnace inlet. Utilizing the residual heat after quenching (surface temperature 190-210℃), a multi-point pneumatic clamping device adapted to irregular curved surfaces is used to precisely fix key points of the profile. Ultrasonic vibration at a frequency of 32kHz and an amplitude of 22μm is applied for 42 seconds using an ultrasonic transducer. The coupling effect of ultrasonic vibration and residual temperature promotes micro-slip at grain boundaries to release internal stress. At the same time, a slight shaping force of no more than 5MPa is applied to correct micron-level warping or twisting defects on the curved surface caused by uneven cooling. Final testing showed that the profile had a tensile strength of 288MPa, a yield strength of 256MPa, an elongation of 8.25%, and a hardness of 86.5HB. The surface form and position tolerance was reduced by more than 40% compared with the traditional process, and the subsequent machining allowance could be reduced by 0.07mm.

[0074] Example 8 This embodiment targets recycled aluminum profiles with complex cross-sections featuring a grooved or concave-convex groove structure (maximum wall thickness 10mm, minimum wall thickness 2.5mm, wall thickness ratio 4:1). The specific steps are as follows: Pre-treatment of recycled aluminum raw materials: The recycled waste container aluminum profiles are sorted, and after the surface steel frame and connectors are manually removed, they are passed through a magnetic separator (to adsorb residual iron impurities), an eddy current separator (to separate non-ferrous metals), and an air separator (to remove dust and light debris) to complete deep impurity removal. The processed waste aluminum is then fed into a jaw crusher (920 r / min) to crush it into aluminum particles with a particle size of 42 mm. During the crushing process, a circulating cooling water system continuously sprays 24°C cooling water to prevent the aluminum particles from oxidizing. The aluminum particles are then sent to an alkaline washing tank equipped with heating and circulation devices, and are washed with a 7.5% sodium hydroxide solution at 55°C for 15.5 min to remove surface oil and oxide film. After being rinsed with clean water until neutral by a spray cleaning machine, they are sent to a hot air circulating dryer and dried at 142°C for 2.3 h to ensure that the aluminum particles are dry, clean, and free of moisture and impurities.

[0075] Composition adjustment: Al-20Si, Al-10Mg, Al-30Cu, and Al-15Mn master alloys are added to aluminum granules using an automatic weighing and feeding device to achieve a mass ratio of Si 1.05%, Mg 0.52%, Cu 0.16%, Mn 0.075%, with the balance being Al. The aluminum granules and master alloys are then fed into a double cone mixer and mixed at a speed of 300 r / min for 15 min. The three-dimensional mixing motion of the double cone mixer ensures that the alloy elements are evenly dispersed, forming a mixed raw material with consistent composition.

[0076] Heating and melting: The mixed raw materials are put into a regenerative continuous heating furnace, and nitrogen with a purity of 99.99% is introduced through a nitrogen generator to control the oxygen content in the furnace to 0.0085% and create an inert protective atmosphere. The temperature is raised to 605℃ at a heating rate of 7.2℃ / min and held for 2.4h. During this period, the furnace temperature and melt state are monitored every 30min to ensure that the mixed raw materials are fully melted and the composition is uniform, avoiding oxidation and loss of alloying elements, and obtaining stable molten aluminum.

[0077] Extrusion Molding: Molten aluminum is conveyed to the extruder barrel through an insulated pipe (to maintain the melt temperature). The barrel is preheated to 568℃, and a vacuum pump is used to evacuate the vacuum inside the barrel to 0.085MPa to prevent oxidation of the molten aluminum upon contact with air. The extrusion die is made of H13 hot work die steel with a nitrided surface (nitrided layer thickness 0.15mm, surface hardness 935HV). The die core cone angle is designed to be 37°, and the fillet radius at the die entrance is 6.8mm to meet the forming requirements of the groove structure. During the extrusion process, the extruder pressure is set to 22MPa, the extrusion speed is controlled at 5.5mm / s, and the die temperature is maintained at 425℃ through a die heating device to ensure that the melt fully fills the groove cavity. Continuous extrusion yields a preliminary groove structure aluminum profile. This process ensures that the profile dimensional accuracy reaches ±0.085mm and the surface roughness Ra1.35μm. Meanwhile, the laser-induced breakdown spectroscopy (LIBS) online composition probe scans the surface of the profile every 30 seconds and feeds back the composition data to the PLC batching system in real time. The system automatically fine-tunes the amount of intermediate alloy added in the next batch based on the deviation, with an adjustment step of no more than 0.02%. After three consecutive qualified tests, the inkjet printer prints a traceability code to achieve composition traceability.

[0078] Online quenching: The pre-formed grooved profile immediately enters the online air-fog quenching device. The cooling medium is a compressed air-water mixture with a water mass ratio of 12.5%. It is held at 522℃ for 12.5 minutes. The profile temperature is monitored in real time by a temperature sensor to ensure that the cooling rate is stable at 22.5℃ / s. This quickly fixes the supersaturated solid solution inside the profile and avoids cracking of the grooved structure due to stress concentration.

[0079] Aging Treatment: The quenched profiles were transferred to an electrically heated aging furnace and heated to 132℃ at a heating rate of 4.5℃ / min, held for 4.8 hours. During the aging process, the furnace temperature was calibrated every hour, with temperature fluctuations strictly controlled within ±2℃. Aging treatment promotes uniform precipitation of the strengthening phase, improving the mechanical properties of the profiles. Simultaneously, during the residual heat stage of quenching (profile surface temperature 200-220℃), an ultrasonic vibration shaping process was initiated. Key parts of the grooves were fixed using a multi-point pneumatic clamping device, and ultrasonic vibration at a frequency of 36kHz and an amplitude of 26μm was applied for 38 seconds using an ultrasonic transducer to release internal stress and correct micron-level dimensional and positional deviations in the grooves. Final test results showed that the profiles had a tensile strength of 292MPa, a yield strength of 262MPa, an elongation of 8.4%, and a hardness of 87.5HB. The dimensional accuracy of the groove structure was stable, allowing for a reduction of 0.08mm in subsequent machining allowances and an increase in yield of 3-5%.

[0080] Example 9 This embodiment targets recycled aluminum profiles with complex cross-sections featuring a grooved or concave-convex groove structure (maximum wall thickness 9.5mm, minimum wall thickness 1.9mm, wall thickness ratio 5:1). The specific steps are as follows: Pre-treatment of recycled aluminum raw materials: The recycled scrap aluminum profiles from ships are sorted, and after the surface anti-corrosion coating and steel connectors are manually removed, they are sequentially passed through a magnetic separator (strong magnetic field adsorbs iron impurities), an eddy current separator (separates non-ferrous metals), and a wind separator (removes light impurities) to complete deep impurity removal. The processed scrap aluminum is then fed into a jaw crusher (980 r / min) and crushed into aluminum particles with a particle size of 48 mm. During the crushing process, 25°C cooling water is continuously sprayed to cool the aluminum particles and prevent oxidation. The crushed aluminum particles are then placed in a washing tank, and a 7.8% sodium hydroxide solution is added. The particles are immersed and washed at 57°C for 14.5 min, during which ultrasonic cleaning at a frequency of 40 kHz is used to improve the removal efficiency of surface oil and oxide film. After washing, the aluminum particles are rinsed with deionized water until the pH value is 7. Finally, they are placed in a drying oven and dried at 148°C for 2.1 h to remove surface moisture and ensure the cleanliness of the raw materials.

[0081] Composition adjustment: Al-20Si, Al-10Mg, Al-30Cu, and Al-15Mn master alloys are added to the dried aluminum granules. Through composition calculation and automatic weighing, the mass ratio of alloy elements in the final mixed raw material is Si 1.15%, Mg 0.58%, Cu 0.19%, Mn 0.095%, with the balance being Al. The aluminum granules and master alloys are placed in a mixer and mixed at a speed of 350 r / min for 20 min. High-speed mixing ensures that the alloy elements are fully integrated with the aluminum granules to form a uniformly composed mixed raw material.

[0082] Heating and melting: The mixed raw materials are fed into a regenerative continuous heating furnace, which is protected by nitrogen gas with a purity of 99.99% and the oxygen content in the furnace is controlled to be ≤0.007%. The temperature is raised to 618℃ at a heating rate of 7.8℃ / min and held for 2.1h. During this period, the temperature uniformity in the furnace is tested to ensure that the temperature difference between different areas in the furnace does not exceed ±3℃, so as to avoid local overheating or insufficient melting, and finally obtain molten aluminum material with uniform composition.

[0083] Extrusion Molding: Molten aluminum is fed into the extruder barrel, which is heated to 578°C. The vacuum inside the barrel is controlled at 0.089MPa to isolate it from air and prevent oxidation. The extrusion die is a custom-made H13 steel die with a nitrided surface (nitrided layer thickness 0.19mm, surface hardness 945HV). The die core cone angle is designed to be 43°, and the die orifice radius is 7.8mm, which is suitable for filling the groove structure with a large wall thickness ratio. During extrusion, the extruder pressure is set to 24.5MPa, the extrusion speed is adjusted to 7.5mm / s, and the die temperature is maintained at 445°C by the heating system to ensure that the melt fully fills the groove cavity and avoids insufficient filling or dimensional deviation. The profile output status is observed in real time during the extrusion process to ensure that the initially formed profile has no obvious defects, and ultimately ensures that the profile dimensional accuracy reaches ±0.08mm and the surface roughness Ra1.25μm. Meanwhile, the laser-induced breakdown spectroscopy (LIBS) online composition probe scans the surface of the profile every 30 seconds, and the data is transmitted back to the PLC batching system in real time. The system automatically fine-tunes the amount of intermediate alloy added in the next batch according to the composition deviation, forming a closed-loop control; qualified batches are marked with traceability codes to achieve composition traceability.

[0084] Online quenching: The pre-formed profile is quickly fed into the air-mist quenching device. The water content in the cooling medium is 14.5% by mass, the quenching temperature is set at 528℃, and the holding time is 10.5 minutes. By adjusting the fan speed and water pump flow rate, the cooling rate of the profile is stabilized at 24.5℃ / s, which quickly fixes the supersaturated solid solution and prevents the groove structure from cracking or deforming due to excessive wall thickness differences.

[0085] Aging Treatment: After quenching, the profiles are placed in an electrically heated aging furnace and heated to 138℃ at a rate of 4.8℃ / min, held at that temperature for 4.2 hours. The furnace temperature is recorded every hour during aging to ensure fluctuations are within ±2℃. After cooling to room temperature, low-temperature aging promotes uniform precipitation of the strengthening phase, improving mechanical properties. Simultaneously, during the residual heat stage of quenching (profile surface temperature 180-200℃), ultrasonic vibration at a frequency of 38kHz and an amplitude of 28μm is applied to the thin-walled portion of the groove for 35 seconds. This, combined with multi-point pneumatic clamping, completes the shaping process, releasing internal stress and correcting morphological defects. Final testing shows that the profile has a tensile strength of 298MPa, a yield strength of 268MPa, an elongation of 8.8%, and a hardness of 89.5HB. The groove structure exhibits high dimensional accuracy, allowing for a reduction of 0.09mm in subsequent machining allowances, meeting the requirements of high-end structural components.

[0086] Example 10 This embodiment targets recycled aluminum profiles with complex cross-sections and multi-cavity structures (maximum wall thickness 8.8mm, minimum wall thickness 2.2mm, wall thickness ratio 4:1). The specific operating steps are as follows: Pre-treatment of recycled aluminum raw materials: The recycled waste photovoltaic bracket aluminum profiles undergo targeted impurity removal. First, a magnetic separator generates a strong magnetic field to adsorb ferromagnetic impurities (such as installation bolts and bracket fragments) mixed in the raw materials. Then, plastic parts (such as insulating plastic sleeves and plastic fasteners) are manually sorted to remove them, ensuring the purity of the raw materials. The treated waste aluminum is then fed into a jaw crusher (910 r / min) and crushed into aluminum particles with a diameter of 36 mm. During the crushing process, a circulating cooling water system is activated to continuously spray 23°C cooling water to prevent the aluminum from being damaged. The aluminum particles oxidize due to friction and increased temperature. They are then sent to an alkaline washing tank equipped with heating and circulating stirring devices, where they are cleaned with a 6.2% sodium hydroxide solution at 53°C for 17.5 minutes to thoroughly remove residual oil, dust, and oxide film from long-term use. The aluminum particles are then rinsed with clean water using a spray cleaning machine until the pH is neutral. Finally, they are sent to a hot air circulating dryer and dried at 132°C for 2.6 hours to ensure that the aluminum particles are dry and free of moisture and impurities, laying a raw material foundation for subsequent multi-cavity molding to avoid bubble defects.

[0087] Composition Adjustment: Al-20Si, Al-10Mg, Al-30Cu, and Al-15Mn master alloys are precisely added to the dried aluminum granules using an automatic weighing and adding device. The mass ratio of alloying elements is strictly controlled to be 0.92% Si, 0.46% Mg, 0.13% Cu, and 0.062% Mn, with the balance being Al. The aluminum granules and master alloys are then fed into a double-cone mixer and mixed at 280 r / min for 18 min. The tumbling mixing characteristics of the double-cone structure ensure that the alloying elements are evenly distributed in the aluminum granules, avoiding differences in mechanical properties in different areas of the multi-cavity mixture due to uneven composition, thus forming a stable mixed raw material.

[0088] Heating and melting: The mixed raw materials are put into a regenerative continuous heating furnace. Nitrogen gas with a purity of 99.99% is introduced into the furnace through a nitrogen generator to control the oxygen content in the furnace to 0.0092%, creating an inert protective atmosphere to isolate air. The furnace is slowly heated to 592℃ at a heating rate of 6.2℃ / min and held at that temperature for 2.7h. During this period, samples are taken regularly to test the melting state of the aluminum material (through melt flow test and rapid composition detection) to ensure that there are no unmelted particles and the composition is uniform, avoiding oxidation reaction and loss of alloying elements. Finally, a stable molten aluminum material is formed to ensure the consistency of subsequent multi-cavity filling.

[0089] Extrusion Molding: Molten aluminum is injected into the extruder through a tilting, insulated flow channel (to maintain a stable melt temperature and prevent localized cooling that could lead to differences in flowability). A hydraulic plunger then pushes it into a preheated, electrically heated barrel at 563°C. A flow divider cone and a perforated plate are installed at the end of the barrel. The flow divider cone is designed for a multi-cavity structure, ensuring uniform flow of the melt into different cavities. The perforated plate filters out any remaining minute impurities in the molten material (such as incompletely cleaned plastic debris or metal oxides). The plunger continues to advance, causing the melt to flow in a laminar state at a pressure of 20.8 MPa and a velocity of 4.2 mm / s, before entering the H13 hot work die steel. The manufactured gradient extrusion die (nitrided layer thickness 0.125mm, surface hardness 922HV, core cone angle 34°, die orifice radius 6.3mm) features a funnel-shaped guide zone at the die inlet, adapting to the multi-channel filling requirements of the multi-cavity structure and guiding the melt smoothly to the multi-cavity cavity formed by the core and die sleeve. The die heating furnace maintains a 412℃ environment to ensure that the melt fully fills each cavity without dead corners. The entire extrusion process is carried out in a barrel vacuum environment maintained by a vacuum pump at 0.083MPa, effectively avoiding air bubble entrapment and ensuring that the dimensional accuracy of the multi-cavity profile reaches ±0.092mm and the surface roughness Ra1.48μm. Meanwhile, an online composition probe for laser-induced breakdown spectroscopy (LIBS) is installed at the extruder outlet. It performs a rapid scan of the profile surface every 30 seconds and provides feedback on the measured values ​​of Si, Mg, Cu, and Mn elements within 30 seconds. The data is transmitted back to the front-end PLC batching system in real time via industrial Ethernet. The deviation is calculated by comparing the data with the target composition range. The PLC system automatically fine-tunes the amount of intermediate alloy added in the next batch based on the deviation, with an adjustment step size not exceeding 0.02%, forming a closed-loop control of "extrusion-feedback-batching". When the results of three consecutive tests are all within ±0.05% of the target median, the system determines that the batch is qualified and prints a traceability code on the profile surface using an inkjet printer, realizing the traceability of the composition of a single multi-cavity profile.

[0090] Online quenching: The multi-cavity aluminum profile after extrusion is immediately sent to the air-mist quenching device. The air compressor and high-pressure water pump work together to provide a compressed air-water mixture with a water mass ratio of 11.2% as the cooling medium. The profile is held at 513℃ for 13.8 minutes, and the cooling rate is controlled at 21.2℃ / s. The supersaturated solid solution inside the profile is fixed by rapid cooling, which avoids uneven stress distribution caused by the difference in wall thickness of different cavities and prevents deformation or cracking defects.

[0091] Aging treatment: The quenched multi-cavity profile is sent into an electric heating aging furnace and heated to 126℃ at a heating rate of 4.1℃ / min. It is held for 5.3h. During this period, the furnace temperature is calibrated every 1h by a PID temperature controller to ensure that the temperature fluctuation is controlled within ±2℃. Through low-temperature aging treatment, the strengthening phases such as Mg2Si inside the profile are uniformly precipitated, which significantly improves the consistency of mechanical properties in various regions of the multi-cavity profile. Meanwhile, an ultrasonic vibration shaping section is added between the quenching outlet and the aging furnace inlet. Utilizing the residual heat after profile quenching (surface temperature 190-210℃), an ultrasonic vibration with a frequency of 30kHz and an amplitude of 20μm is applied for 45s through a multi-point pneumatic clamping device adapted to the multi-cavity structure (clamping points are designed for each cavity wall to avoid clamping deformation), in conjunction with an ultrasonic transducer. The coupling effect of ultrasonic vibration and residual temperature promotes micro-slip of grain boundaries to release internal stress. At the same time, a slight shaping force of no more than 5MPa is applied to correct micron-level warping or twisting defects (such as cavity port flatness deviation and cavity sidewall verticality deviation) caused by uneven cooling in the multi-cavity structure. Final testing showed that the multi-cavity profile had a tensile strength of 286MPa, a yield strength of 256MPa, an elongation of 8.2%, and a hardness of 86.2HB. The dimensional accuracy of each cavity was stable, and the overall curvature was reduced by more than 40% compared with the traditional process. The subsequent machining allowance could be reduced by 0.07mm, meeting the high precision and mechanical performance requirements of photovoltaic brackets for multi-cavity structural profiles.

Claims

1. A method for extrusion of a complex profile from a recycled aluminium section, characterised in that, The following steps are included: S1. Raw material pretreatment: The waste aluminum after impurity removal is crushed to form aluminum particles. The aluminum particles are then washed with a sodium hydroxide solution with a mass concentration of 5-8% at a temperature of 50-60℃ for 15-20 minutes. After that, they are rinsed with clean water until neutral and dried at a temperature of 120-150℃ for 2-3 hours. S2. Composition adjustment: Add intermediate alloy to the pretreated aluminum granules and mix them to form a mixed raw material; S3. Heating and melting: The mixed raw materials are heated and melted using a regenerative continuous heating furnace. The temperature is increased to 580-620℃ at a rate of 5-8℃ / min and held for 2-3 hours to obtain the molten material. S4. Extrusion molding: Molten material is extruded through an extruder and gradient extrusion die to form aluminum profiles with complex cross-sections such as multi-cavity, irregular curved surfaces, or concave and convex grooves. At the same time, the composition of the aluminum profile is detected online by laser-induced breakdown spectroscopy, and the PLC batching system provides real-time feedback to automatically fine-tune the amount of intermediate alloy added in the next batch. S5. Online quenching: The extruded aluminum profiles are quenched using a wind-mist quenching device. At the same time, a compressed air-water mixture with a water mass ratio of 10-15% is used as the cooling medium and held at a temperature of 500-530℃ for 10-15 minutes. S6. Aging treatment: The quenched aluminum profiles are aged using an electric heating aging furnace. The temperature is raised to 120-140℃ at a heating rate of 3-5℃ / min and held for 4-6 hours. The furnace temperature is calibrated every 1 hour during the process.

2. A method of extruding a regenerative aluminium profile of complex cross-section according to claim 1, characterised in that, In S1, the removal of impurities from waste aluminum is carried out through a combination of manual and mechanical methods. The mechanical removal includes using a magnetic separator to generate a strong magnetic field to adsorb ferrous metal impurities in the waste aluminum, using an eddy current separator to generate an eddy current effect to separate non-ferrous metal impurities such as copper and zinc, and using a wind separator to create airflow velocity differences to remove lightweight plastic and rubber impurities.

3. The method for extruding recycled aluminum profiles with complex cross-sections according to claim 1, characterized in that, In S2, the intermediate alloy includes Al-20Si, Al-10Mg, Al-30Cu, and Al-15Mn. The final percentage of the alloying elements in the total mass of the mixed raw materials is controlled within the following range: Si 0.8–1.2%, Mg 0.4–0.6%, Cu 0.1–0.2%, Mn 0.05–0.1%, with the balance being Al.

4. The method for extruding recycled aluminum profiles with complex cross-sections according to claim 1, characterized in that, In step S3, protective nitrogen gas supplied by a nitrogen generator is introduced into the regenerative continuous heating furnace. The nitrogen gas purity is ≥99.99%, and the oxygen content in the furnace is ≤0.01%, forming an inert atmosphere.

5. The method for extruding recycled aluminum profiles with complex cross-sections according to claim 1, characterized in that, In S4, the gradient extrusion die is made of H13 hot work die steel, and the die surface is nitrided with a nitrided layer thickness of 0.1-0.2 mm and a surface hardness of 900-950 HV. The die inlet is provided with a trumpet-shaped guide area.

6. The method for extruding recycled aluminum profiles with complex cross-sections according to claim 1, characterized in that, In step S4, the laser-induced breakdown spectrum online detection frequency is once every 30 seconds, which is used to provide feedback on the measured values ​​of Si, Mg, Cu, and Mn elements. The measured value data is transmitted back to the PLC batching system via industrial Ethernet.

7. The method for extruding recycled aluminum profiles with complex cross-sections according to claim 1, characterized in that, In step S5, the cooling medium of the air-fog quenching device is evenly sprayed onto the surface of the aluminum profile through multiple sets of nozzles.

8. The method for extruding recycled aluminum profiles with complex cross-sections according to claim 1, characterized in that, In step S6, the electric heating aging furnace adopts a PID temperature control system, which automatically calibrates the furnace temperature every 1 hour.

9. The method for extruding recycled aluminum profiles with complex cross-sections according to claim 1, characterized in that, In step S1, the drying process uses a hot air circulating dryer with an air velocity controlled at 1.5-2 m / s and an aluminum particle moisture content ≤0.1%.

10. The method for extruding recycled aluminum profiles with complex cross-sections according to claim 1, characterized in that, In step S5, an ultrasonic vibration shaping section is set after quenching. When the surface temperature of the aluminum profile is still maintained at 180–220℃, an ultrasonic vibration with a frequency of 20–40kHz and an amplitude of 10–30μm is applied to the thin-walled part of the aluminum profile by a multi-point pneumatic clamping device in conjunction with an ultrasonic transducer for a duration of 30–60s.

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