Production method for manufacturing high-strength high-silicon aluminum alloy capable of being rapidly extruded by using recycled waste aluminum

Abstract

The invention discloses a production method for manufacturing a high-strength high-silicon aluminum alloy capable of being rapidly extruded by using recycled waste aluminum, which comprises the following steps of: crushing and screening aluminum waste to leave aluminum-containing fragments, and separating aluminum materials from the aluminum-containing fragments; preheating an aluminum material and melting the aluminum material into a molten aluminum melt A; refining, stirring and slagging off the melt A, and blowing to remove hydrogen; after refining, transferring to an alloying furnace, and adjusting components to obtain an aluminum alloy melt B; adding an AlTiB wire into the melt B, and carrying out online degassing and filtering to obtain a melt C; casting the melt C to obtain an aluminum alloy round cast ingot D; and the round cast ingot D is subjected to homogenizing annealing, an aluminum alloy round cast ingot E is obtained, and production and machining of the high-strength and high-silicon aluminum alloy are completed. According to the method, the recycled waste aluminum serves as the raw material, the inclusivity of the Si content and the Fe content is high, the waste aluminum is utilized at a guaranteed level, the problem that secondary aluminum is immature in use in the aspect of extruded profiles is solved, and the method has important significance on recycling of aluminum resources and sustainable development of the aluminum production industry.

Description

Technical Field

[0001] The present invention relates to the technical field of nonferrous metals, and in particular to a production method for manufacturing a high-strength and high-silicon aluminum alloy that can be rapidly extruded by using recycled waste aluminum. Background Art

[0002] Aluminum alloy has become the second most widely used alloy worldwide due to its high strength, lightweight, corrosion resistance, and long lifespan. Aluminum bars extruded from aluminum alloys are smelted and cast from aluminum ingots, the raw material for which is bauxite, a non-renewable resource. Currently, my country's scrap aluminum recycling methods are primitive and poorly managed, leading to widespread mixing of scrap metal of varying qualities and types. Therefore, promoting the recycling of recycled aluminum is urgent.

[0003] The recycling of recycled aluminum is mainly divided into two modes: downgrading and grade-preserving. Downgrading is the simple processing of scrap aluminum alloys and their use in areas with lower performance requirements, such as low-end cast aluminum alloys. In my country's recycled aluminum industry, a large amount of scrap aluminum is downgraded, which not only fails to fully realize the potential value of scrap aluminum, but also results in a huge waste of resources. Grade-preserving utilization, on the other hand, uses technical means to reuse scrap aluminum alloys in high-performance scenarios, such as the aerospace field. However, due to the complex quality sources of recycled aluminum, achieving grade-preserving utilization faces many challenges, including high equipment costs, complex processes, and strict requirements on the quality and source of scrap aluminum.

[0004] The extrusion process of recycled wrought aluminum alloys is particularly important in grade-retention utilization, but current technology still faces a bottleneck: the inability to achieve rapid extrusion of recycled wrought aluminum alloys. Although domestic and foreign research institutes and companies have conducted extensive research on the recycling of recycled aluminum in recent years and have achieved certain results, rapid extrusion technology is still insufficient.

[0005] For example, patent CN 112176200A discloses a recycling production process for aluminum die-casting waste, but does not involve the extrudability of the alloy; patent CN 111926186A proposed an aluminum alloy recycling process, but did not analyze the subsequent performance of the alloy; Patent CN200510002497.1 achieved rapid extrusion by cooling the mold and profile by nitrogen and liquid nitrogen; Patents CN202210622378.X, CN201910899542.X and CN201910898972.X improved the structure by adding rare earth elements to achieve rapid extrusion; Patent CN202210597369.X refined the grains by adding Al-5Ti-B alloy refiner, and achieved low-temperature rapid extrusion by combining stirring and shaking; Patent CN201410596826.9 reduced the temperature of the aluminum rod by controlling the Mg and Si content and the pressure relief angle of the diverter bridge, thereby achieving low-temperature rapid extrusion; Patent CN202122576938.6 used the multi-level distribution of the diverter bridge to reduce the extrusion force on the pressure-bearing surface and the mold, thereby increasing the extrusion speed.

[0006] Although the above research has made certain progress in specific aspects, there is still a lack of a mature production method that can use recycled scrap aluminum to produce high-strength, high-silicon aluminum alloys that can be quickly extruded.

[0007] Therefore, how to solve the above-mentioned deficiencies in the prior art has become the subject to be studied and solved by the present invention. Summary of the Invention

[0008] The purpose of the present invention is to provide a production method for producing a high-strength and high-silicon aluminum alloy that can be quickly extruded using recycled waste aluminum.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is: A method for producing a high-strength, high-silicon aluminum alloy capable of rapid extrusion using recycled aluminum scrap comprises: Step 1: Pre-processing the aluminum waste including crushing and sorting to obtain aluminum material; Step 2: preheating the aluminum material to remove moisture and some organic matter; melting the preheated aluminum material to obtain melt A; Step 3: Refining the melt A, removing slag in the melt A by stirring and skimming; Step 4: Transfer the refined melt A to an alloying furnace and adjust the composition to obtain aluminum alloy melt B; Step 5: Adding AlTiB wire as a grain refiner to the melt B in an amount of 0.1-0.15% of the weight of the melt B; then, performing online degassing and filtration on the melt B to obtain melt C; Step 6: Casting the melt C to obtain an aluminum alloy round ingot D; Step 7: Perform homogenization annealing on the round ingot D, and obtain the aluminum alloy round ingot E after cooling, thereby completing the production and processing of the high-strength and high-silicon aluminum alloy.

[0010] In the above solution, the aluminum scrap is preferably primary and secondary aluminum scrap, as specified in GB / T 34640.1-2017. Non-metallic impurities include plastic, cardboard, and the like. The paint stripping process is performed in a rotary kiln. The aluminum obtained in step 1 is of higher purity than the aluminum scrap.

[0011] As a further technical solution, in step 2, the high-temperature flue gas discharged from the smelting chamber can be used for preheating, thereby achieving effective energy saving.

[0012] According to a further technical solution, the high-strength and high-silicon aluminum alloy comprises the following components in percentage by mass: Si 4.0-4.9%, Mg 0.6-0.9%, Cu≤0.1%, Mn 0.36-0.72%, Cr≤0.1%, Fe 0.3-0.6%, Sr 0.05-0.4%, Zn≤0.25%, Ni≤0.05%, Ti≤0.15%, the balance is Al; and a single impurity element ≤0.05%.

[0013] In step 4, the composition adjustment is carried out with the above components as the target. Before adjustment, the composition of the aluminum liquid is first confirmed by a composition analyzer to determine whether addition of corresponding elements is required and the amount of addition.

[0014] In a further technical solution, in step 1, the pretreatment is as follows: feeding the aluminum scrap into a crusher for crushing and screening, leaving aluminum-containing fragments with a diameter of less than 110 mm, then removing iron-containing impurities in the aluminum-containing fragments by magnetic separation, then removing non-metallic impurities by eddy current separation, and finally performing X-ray separation and paint stripping to obtain the aluminum material; In step 2, the aluminum material is preheated by placing the aluminum material into a preheating chamber and preheating it to 400-500°C for 20-30 minutes. The preheated aluminum material is then smelted by transferring the preheated aluminum material through a closed passage to a smelting chamber, where the temperature is raised to 700-750°C and melted into liquid aluminum to obtain the melt A. In step 3, the refining process is as follows: adding a refining agent to melt A, and stirring melt A at least twice, each stirring operation is performed at a speed of 300-800 rpm, and the time is 8-12 minutes. After each stirring operation, the melt is allowed to stand for at least 5 minutes, and after standing, the slag in the melt A is removed by skimming; While refining the melt A, an inert gas is continuously introduced into the melting chamber to remove hydrogen in the melting chamber; In step 4, the temperature of melt A is controlled to be 720-740° C. when adjusting the composition of melt A; In step seven, the round ingot D is subjected to homogenization annealing, firstly heated to 550° C. at a heating rate of 90° C. / h, then kept at this temperature for 8 hours, and finally taken out of the furnace and water-cooled to obtain the aluminum alloy round ingot E after cooling.

[0015] A further technical solution is that in step 5, the TiAl3 phase in the AlTiB wire is evenly distributed in the AlTiB wire, and the TiAl3 phase density is ≥120 / mm 2 , and the size of each TiAl3 phase is less than 25μm.

[0016] A further technical solution further includes step eight, heating the round ingot E to 490° C. and then extruding it, and then quenching it in-line with water to obtain the aluminum profile F; The aluminum profile F is artificially aged at an extrusion speed of 5-7.5 mm / s at 175° C. for 8 hours to obtain a high-strength, high-silicon aluminum alloy profile. During extrusion, the extrusion ratio is controlled at 70.

[0017] A further technical solution is that in step eight, during extrusion, the extrusion die adopts a guide die design, and the number of diversion bridges is greater than or equal to 4, and the thickness D of the guide plate is greater than or equal to 4. ; Depth of welding chamber H= (5~6) The diameter of the aluminum rod is the diameter of the round ingot E.

[0018] The thickness of the guide plate and the depth of the welding chamber are both in mm.

[0019] A further technical solution is that in step eight, during extrusion, the length L1 of the die working band is 2-6 mm, the length L2 of the part in contact with the aluminum rod is 0.2-0.5 mm, and the rest of the working band has an inclination angle α of 5-10°.

[0020] In the above solution, the remaining portion of the working band is the portion obtained by subtracting L2 from L1.

[0021] In the above solution, the thickness D of the guide plate and the depth H of the welding chamber are both expressed in mm.

[0022] A further technical solution includes an upper mold and a lower mold, wherein the upper mold is the guide plate; and the welding chamber is formed between the upper mold and the lower mold.

[0023] According to a further technical solution, the upper mold has four feeding cavities and the lower mold has one discharging cavity.

[0024] According to a further technical solution, the portion of the welding chamber located on the upper surface of the lower mold is cross-shaped, and the cross-shaped portion is aligned with the four feed cavities of the upper mold in the upper and lower directions.

[0025] According to a further technical solution, the discharge cavity is cross-shaped.

[0026] According to a further technical solution, the highest point of the welding chamber is located in the middle of the upper surface of the lower mold, and the number of the welding chambers is four; The low point of the welding chamber is recessed on the upper surface of the lower mold and is located on the side of each high point in the circumferential direction.

[0027] According to a further technical solution, in step three, the stirring operation is performed using a stirring paddle; The stirring paddle comprises a bottom blade, a middle blade and an upper blade which are spaced apart from each other along the axial direction from bottom to top; The bottom blades serve as propulsion blades for the upward flow of the aluminum liquid, and the blades form an angle of 35-55 degrees with the horizontal plane; The middle blades are variable-section blades, the thickness of each blade gradually decreases from the root to the tip, and a serrated structure is provided on the edge of the blade; a plurality of spiral grooves are provided on the surface of the blade; The upper blade is an anchor blade combination, which has an outer layer and an inner layer; wherein the outer layer is an upward curved arc stirring rod, and the inner layer is a guide blade with convex points.

[0028] In a further technical solution, a stirring paddle is disposed in a molten pool, and the diameter of the bottom blade is 0.7-0.85 times the diameter of the bottom of the molten pool. With this design, the bottom blade can expand the stirring coverage of the bottom area of the molten pool and push the bottom aluminum liquid upward.

[0029] According to a further technical solution, the upper surface of each blade of the bottom blade is evenly distributed with a plurality of protrusions and is provided with a plurality of grooves at intervals.

[0030] According to a further technical solution, the outer edges of the bottom blades are all arc-shaped curves.

[0031] According to a further technical solution, the diameter of the middle blade is larger than that of the bottom blade, and the main bodies of the middle blades are all designed to be straight.

[0032] According to a further technical solution, there are two arc-shaped stirring rods on the outer layer of the upper blade, and they are symmetrically arranged.

[0033] According to a further technical solution, the guide blades in the inner layer of the upper blades are arranged in a radial pattern that is inclined upward.

[0034] According to a further technical solution, the stirring paddle is configured to have a heat-resistant alloy steel body and a nitrided surface.

[0035] In the above solution, the protrusions are used to further disrupt the flow of the aluminum liquid.

[0036] In the above scheme, the special blade structure of the bottom blade can enhance the turbulence generated when the blade pushes the aluminum liquid, increase the collision and shear opportunities with Si, Fe, and Mn particles, and use the turbulence to stir up the Fe and Mn particles deposited at the bottom, creating conditions for subsequent uniform distribution.

[0037] In the above scheme, the edge of the central blade is serrated with a pitch of 10-15mm and a depth of 5-8mm. Several spiral grooves are also formed on the blade surface, each 2-3mm deep. This design significantly enhances the shear and vortex effects on the molten aluminum during blade rotation, breaking up and spheroidizing Si particles in the complex flow field. It also radially disperses Fe and Mn particles lifted from the bottom, ensuring a better connection between the bottom and top molten aluminum. This structure significantly enhances the shear and vortex effects on the molten aluminum during blade rotation. The spiral grooves guide the molten aluminum into a localized spiral flow, increasing the mixing of elements and ensuring thorough mixing throughout the molten pool, promoting uniform distribution of Si, Fe, and Mn particles. In the above solution, the upper blades redirect the flow of the molten aluminum at the top, creating a complex circulation flow field that prevents Si, Fe, and Mn particles from concentrating at the top. Furthermore, the stirring process does not damage the top coating and oxide layer, ensuring that the molten aluminum is not susceptible to secondary contamination. Through a special flow field design, Si, Fe, and Mn particles processed in the bottom and middle sections are further evenly dispersed at the top, avoiding local concentration differences and enhancing the stirring effect throughout the entire molten pool.

[0038] The protrusions are used to further disrupt the flow of the aluminum liquid, and can be implemented using circular protrusions with a diameter of 8-10 mm.

[0039] In a further technical solution, the stirring paddle is made of heat-resistant alloy steel, and the surface of the stirring paddle is nitrided. This can enhance the surface hardness and anti-adhesion properties, prevent the adhesion of Si, Fe, and Mn particles, and ensure that the stirring effect is not affected.

[0040] The terms “include”, “including”, “have”, etc. used in this document are open-ended terms, meaning including but not limited to.

[0041] Unless otherwise noted, the terms used herein generally have their ordinary meanings in the art, in the context of this application, and in the specific context. Certain terms used to describe this application are discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art regarding the description of this application.

[0042] The working principle and advantages of the present invention are as follows: The present invention recycles scrap aluminum as raw material, has strong tolerance for Si and Fe content, and combines the adjustment of alloy composition to finally obtain a high-strength and high-silicon aluminum alloy that can be quickly extruded and manufactured using recycled scrap aluminum. It successfully realizes the grade-preserving utilization of scrap aluminum, solves the current problem of immature use of recycled aluminum in extruded profiles in my country, and has important practical significance for the recycling of aluminum resources, cost savings of aluminum ingots and aluminum profiles, and the sustainable development of the aluminum production industry.

[0043] Furthermore, the Si content of the present invention is 4.0-4.9%, which is highly tolerant of different types of scrap aluminum in the raw material. This is because recycled aluminum contains some cast aluminum alloy, and the Si content of cast aluminum alloy is much higher than that of extrudable wrought aluminum alloy, which significantly increases the Si content of the alloy. The Si content of the present invention exceeds that of 6XXX wrought aluminum alloys (for example, the Si content of certain 6-series aluminum alloys is 0.4-0.8%). The Si element is primarily present in the alloy in the form of spherical Si, and its content is within the range of cast aluminum alloys. However, it can still be used in the same way as wrought aluminum alloys for extrusion, and the resulting profiles have excellent performance, with high tensile and yield strengths.

[0044] Furthermore, the three-layer stirring paddle design of the present invention can fully remove hydrogen from the melt and promote the homogenization of the melt composition. The bottom blade pushes the bottom aluminum liquid upward and also utilizes a special blade structure to increase the collision and shear opportunities with Si, Fe, and Mn particles. In particular, for Fe and Mn particles, turbulence is used to stir them up from the sediment layer at the bottom of the molten pool, creating conditions for subsequent uniform distribution. The middle blade is not only responsible for radially dispersing the aluminum liquid, but also promotes the spheroidization of Si particles and the uniform distribution of Fe and Mn particles in the aluminum liquid under the action of strong shear force and vortex. The upper blade is designed with a special flow field to further evenly disperse the Si, Fe, and Mn particles that have been processed in the bottom and middle sections at the top, avoiding local concentration differences. The present invention uses an original spiral groove to guide the aluminum liquid to form a local spiral flow, increasing the opportunity for element mixing. In addition, the combination of the serrated structure at the end, the protrusions on the blades, and the arc-shaped stirring rod can fully break up the Si, Fe, Mn and other phases.

[0045] Furthermore, the present invention strictly controls the grade of the grain refiner: the TiAl3 grains are evenly distributed throughout the refined wire, and the TiAl3 grain size is controlled below 25 μm, and the density is controlled to be no less than 120 grains / mm 2 Repeated experiments have shown that the extruded aluminum profiles produced by melting and casting aluminum bars with high-quality grain refiners exhibit smoother surfaces, are free of coarse grains, and possess superior mechanical properties. Furthermore, defects such as streaks and white lines rarely appear on the oxidized surface. The resulting extruded profiles have superior surface quality compared to those produced by casting bars with standard grain refiners.

[0046] Furthermore, the extrusion ratio of the present invention when extruding the product is controlled between 60-140. In this industry, the extrusion ratio is usually between 20-60. The purpose of increasing the extrusion ratio in the present invention is to increase the pressure during the extrusion process, increase the flow stress and strain rate, and promote the crushing of elemental Si. Under high stress conditions, dislocations accelerate proliferation, and high pressure promotes grain boundary migration and recrystallization nucleation, thereby promoting grain refinement. Increasing the extrusion ratio can be achieved by increasing the tonnage of the machine, that is, placing the product on a large-tonnage extruder press for extrusion. In addition, the mold adopts a guide mold (the number of diversion bridges ≥ 4 bridges), and the thickness of the guide plate is thickened on a conventional basis. In addition to enhancing the overall deformation resistance of the guide plate, these two measures are also intended to further increase the extrusion force, promote deformation, accelerate the crushing of elemental Si, refine the grains, and enhance the strength of the alloy.

[0047] Furthermore, the present invention has a deeper welding chamber than conventional molds. Conventional designs usually have a welding chamber value of H 常 = (3~5) The present invention increases the depth of the welding chamber to H= (5~6) The purpose is to strengthen welding and make up for the poor welding problem caused by the existence of the shunt bridge.

[0048] Furthermore, the present invention shortens the die working belt, with an effective length of only 0.2-0.5mm, to avoid the increased pressure caused by previous machine selection and die structure changes. Furthermore, the extremely short working belt reduces friction between the Si element and the working belt, allowing the aluminum to quickly pass through the working belt and be transformed into profiles. This not only facilitates rapid extrusion, but also helps maintain a smooth surface on the profile, reducing the risk of cracks and streaks. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Attachment Figure 1 This is a schematic diagram of the method flow of Example 1 of the present invention; Attachment Figure 2 Schematic cross-sectional view of the extrusion die of Example 1 of the present invention; Attachment Figure 3 for Figure 2 The enlarged view of point I in the middle; Attachment Figure 4 1 is a side view of the extrusion die of Example 1 of the present invention; Attachment Figure 5 for Figure 4 Cross-sectional view along the AA axis; Attachment Figure 6 A top view of the extrusion die of Example 1 of the present invention; Attachment Figure 7 for Figure 6 Cross-sectional view along the BB direction; Attachment Figure 8 for Figure 6Cross-sectional view along the DD direction; Attachment Figure 9 The shape of the secondary welding chamber in the extrusion die of Example 1 of the present invention (from a top view); Attachment Figure 10 A top view of an embodiment of the present invention; Attachment Figure 11 for Figure 10 Cross-sectional view in CC direction; Attachment Figure 12 This is a schematic structural diagram of a stirring paddle according to embodiment 1 of the present invention; Attachment Figure 13 This is an electron microscope image of the AlTiB wire added in step 5 of Example 1 of the present invention; Attachment Figure 14 This is a metallographic image of the round ingot D before homogenization annealing in step seven of Example 1 of the present invention; Attachment Figure 15 This is a metallographic image of the round ingot D after homogenization annealing in step seven of Example 1 of the present invention; Attachment Figure 16 This is a photo of the appearance of the profile product of Example 1 of the present invention; Attachment Figure 17 This is a photo of the appearance of the profile product of Comparative Example 1 of the present invention; Attachment Figure 18 This is a photo of the appearance of the profile product of Comparative Example 2 of the present invention; Attachment Figure 19 This is a photo of the appearance of the profile product of Comparative Example 3 of the present invention; Attachment Figure 20 This is a photo of the appearance of the profile product of Comparative Example 4 of the present invention; Attachment Figure 21 This is a photo of the appearance of the profile product of Comparative Example 5 of the present invention; Attachment Figure 22 This is a photo of the appearance of the profile product of Comparative Example 6 of the present invention.

[0050] In the above figures: 1. Guide plate (upper die); 2. Diverter bridge; 3. Welding chamber; 4. Working zone; D. Thickness of guide plate; H. Depth of welding chamber; L1. Length of mold working zone; 8. Portion in contact with aluminum bar; L2. Length of portion in contact with aluminum bar; α. Inclination angle; 5. Lower die; 6. Feed chamber; 7. Discharge chamber; 9. Secondary welding chamber; P1. High point of welding chamber; P2. Low point of welding chamber; 11. Bottom blade; 12. Middle blade; 13. Upper blade; 14. Protrusion; 15. Groove; 16. Serrated structure; 17. Spiral groove; 31. Curved stirring rod; 32. Guide blade. DETAILED DESCRIPTION

[0051] The present invention will be further described below with reference to the accompanying drawings and embodiments: The present invention will be clearly illustrated below with drawings and detailed descriptions. After understanding the embodiments of the present invention, any person skilled in the art will be able to make changes and modifications based on the techniques taught by the present invention without departing from the spirit and scope of the present invention.

[0052] The terms used herein are for describing specific embodiments only and are not intended to be limiting of the present invention. Singular forms such as "a," "the," "this," "this," and "the" as used herein also include plural forms. Example

[0053] like Figure 1 As shown, a production method for producing a high-strength, high-silicon aluminum alloy that can be quickly extruded using recycled scrap aluminum comprises: Step 1: The aluminum scrap is fed into a crusher for crushing and screening, leaving aluminum-containing fragments with a diameter of less than 110mm. A permanent magnet (or electromagnetic) magnetic separator is then used to remove iron-containing impurities (such as large and small iron pieces and aluminum-clad iron) from the aluminum-containing fragments.

[0054] Aluminum-containing fragments are separated through eddy current separation to obtain aluminum blocks. Non-metallic materials such as plastic, cardboard, and other materials are removed. The aluminum blocks are then separated through X-ray separation to obtain aluminum material, while also removing copper and zinc. Finally, the aluminum blocks are sent back to the rotary kiln for paint removal, resulting in a purer aluminum material (purer than scrap aluminum).

[0055] Step 2: The aluminum material is conveyed into the preheating chamber via a conveyor belt in a double-chamber furnace and preheated to 400-500°C using the high-temperature flue gas discharged from the smelting chamber for 20-30 minutes to remove moisture and some organic matter. The preheated aluminum material is transferred to a smelting chamber through a closed channel, where it is heated to 700-750°C and melted into liquid aluminum to obtain melt A. Step 3: Add NaCl-KCl-NaF mixed salt to melt A as a refining agent, and stir melt A at least twice, with each stirring operation at a speed of 300-800 rpm and a time of 8-12 minutes. After each stirring operation, let it stand for at least 5 minutes. After standing, remove slag (i.e., solid impurities) in melt A by skimming to homogenize the composition of melt A.

[0056] While refining the melt A, high-purity argon is continuously introduced into the melting chamber at a flow rate of 1-3 L / min·t to remove hydrogen from the melting chamber; Step 4: Transfer the refined melt A to an alloying furnace, control the temperature of melt A to 720-740°C, and adjust the composition to obtain aluminum alloy melt B; Step 5: During the launder transfer process, AlTiB wire is added to the melt B in the launder as a grain refiner in an amount of 0.1-0.15% by weight of the melt B; the melt B is then degassed and filtered online to remove hydrogen and other harmful gases in the melt, and a two-stage foam ceramic filter plate is used to filter out large harmful compounds in the melt to make the melt as pure as possible, thereby obtaining melt C; Step 6: semi-continuously casting the melt C at 730° C. to obtain an aluminum alloy round ingot D with a diameter of φ152 mm; Step 7: Homogenization annealing is performed on the round ingot D. First, the temperature is raised to 550℃ at a heating rate of 90℃ / h, then kept at this temperature for 8h, and finally taken out of the furnace and water-cooled. After cooling, the aluminum alloy round ingot E is obtained (see Figure 14 、 Figure 15 ), complete production and processing.

[0057] The high-strength, high-silicon aluminum alloy produced and processed in Example 1 contains the following components in percentage by mass: Si 4.6%, Mg 0.74%, Cu 0.03%, Mn 0.42%, Cr 0.06%, Fe 0.35%, Sr 0.25%, Zn ≤ 0.25%, Ni ≤ 0.05%, Ti ≤ 0.15%, balance Al. Individual impurity elements ≤ 0.05%.

[0058] In step 4, the composition adjustment is carried out with the above components as the target. Before adjustment, the composition of the aluminum liquid is first confirmed by a composition analyzer to determine whether it is necessary to add the corresponding elements and the amount of addition. The following materials can be used for adjustment: Aluminum ingot: Use Al99.7 aluminum ingot that complies with GB / T 1196-2023, and the mass percentage of Al in the ingot is not less than 99.7%; Magnesium ingot: Use magnesium ingot with the grade Mg9990 in accordance with GB / T 3499-2023, and the mass percentage of Mg in the magnesium ingot is not less than 99.9%; Master alloy: Aluminum-based master alloys with grades of AlSi20, AlCu50, AlMn10, AlCr5, and AlSr10 that comply with GB / T 27677-2017 are used.

[0059] Preferably, in step 5, the TiAl3 phase in the AlTiB wire is uniformly distributed in the AlTiB wire, and the TiAl3 phase density is ≥120 / mm 2 , and the size of each TiAl3 phase is less than 25μm (see Figure 13 ).

[0060] Preferably, the method further comprises step eight of heating and extruding the round ingot E, and then water-cooling and quenching the ingot online after extrusion to obtain the aluminum profile F; The aluminum profile F is artificially aged at an extrusion speed of 5-7.5 mm / s, with an aging temperature of 175° C. and a heat preservation time of 8 hours to obtain a high-strength and high-silicon aluminum alloy profile.

[0061] During extrusion, the extrusion ratio is controlled at 60-140.

[0062] During extrusion, the extrusion die adopts a guide die design, such as Figures 2 to 11 , and the number of diversion bridges 2 is greater than or equal to four, the thickness D of the guide plate 1 is greater than ; Depth of welding chamber 3 H= (5~6) The aluminum rod is the round ingot E.

[0063] The length L1 of the mold's working zone 4 is 2-6 mm, of which the length L2 of the portion 8 in contact with the aluminum bar is 0.2-0.5 mm. The remaining portion of the working zone (i.e., L1 minus L2) has an inclination angle α of 5-10°. Subsequently, the blanking knife discharge is similar to that of a conventional mold. The flow rate at different points throughout the profile is controlled by the shape and height of the secondary welding chamber 9. The specific control principle is known from the prior art and is not a key feature of this invention, so it will not be elaborated upon here.

[0064] During extrusion, the extrusion ratio is controlled at 60-140.

[0065] During extrusion, the machine is preferably 1400T, the extrusion speed is preferably 7.5mm / s, the profile temperature at the exit of the beam before extrusion is greater than 500°C, and the profile is water quenched online to room temperature after extrusion to obtain profile F.

[0066] Preferably, the extrusion die includes an upper die and a lower die 5 , the upper die is the guide plate 1 ; the welding chamber 3 is formed between the upper die and the lower die 5 .

[0067] Preferably, the upper mold has four feeding cavities 6 , and the lower mold 5 has one discharging cavity 7 .

[0068] Preferably, Figure 9 As shown, the portion of the welding chamber 3 located on the upper surface of the lower mold 5 is cross-shaped, and the cross-shaped portion is aligned with the four feed cavities 6 of the upper mold in the upper and lower directions.

[0069] Preferably, the discharge cavity 7 is cross-shaped.

[0070] Preferably, the high point P1 of the welding chamber 3 is located in the middle of the upper surface of the lower mold 5, and there are four of them; the low points P2 of the welding chamber 3 are recessed in the upper surface of the lower mold 5 and are located on the side of each high point P1 in the circumferential direction.

[0071] In this embodiment, the thickness D of the guide plate 1 and the depth H of the welding chamber 3 are both expressed in mm.

[0072] In step 3, the stirring operation is performed using a stirring paddle. Figure 12 As shown, the stirring blade includes a bottom blade 11, a middle blade 12 and an upper blade 13 which are spaced apart from bottom to top along the axial direction.

[0073] The bottom blades 11 serve as propulsion blades for the upward flow of the aluminum liquid, and the blades form an angle of 35-55 degrees with the horizontal plane.

[0074] The diameter of the bottom blades 11 is 0.7-0.85 times the diameter of the molten pool bottom, which expands the stirring coverage of the bottom area of the molten pool and pushes the bottom aluminum upward. Each blade has a plurality of protrusions 14 on its upper surface, and is interspersed with grooves 15 (or ridges). The outer edge of each blade is an arc-shaped curve.

[0075] The bottom blade 11 is a spoiler blade. Its special blade structure can enhance the turbulence generated when the blade pushes the aluminum liquid, increase the collision and shear opportunities with the Si, Fe, and Mn particles in the aluminum liquid, and use the turbulence to stir up the Fe and Mn particles deposited at the bottom, creating conditions for subsequent uniform distribution, thereby ensuring the quality of aluminum alloy production.

[0076] Among them, the middle blade 12 is a variable-section blade, the thickness of each blade gradually decreases from the root to the tip, and a serrated structure 16 is set on the edge of the blade, the serration spacing is 10-15mm, and the depth is 5-8mm; several spiral grooves 17 are opened on the blade surface, with a depth of 2-3mm.

[0077] The diameter of the middle blade 12 is larger than that of the bottom blade 11 , and each blade body of the middle blade 12 is designed to be straight.

[0078] The special design requirements of the central blades 12 described above significantly enhance the shear force and vortex effect on the molten aluminum during blade rotation, causing Si particles to be broken up and spheroidized in the complex flow field. Simultaneously, the Fe and Mn particles lifted from the bottom are fully dispersed radially, ensuring a better connection between the bottom and top molten aluminum. This structure significantly enhances the shear force and vortex effect on the molten aluminum during blade rotation. The spiral grooves 17 guide the molten aluminum into a localized spiral flow, increasing the mixing of elements, ensuring sufficient mixing of the molten aluminum throughout the molten pool, and promoting the uniform distribution of Si, Fe, and Mn particles. The upper blade 13 is an anchor blade combination having an outer layer and an inner layer; the outer layer is an upwardly curved arc-shaped stirring rod 31 , and the inner layer is a guide blade 32 with a convex point 14 .

[0079] There are two arc-shaped stirring rods 31 on the outer layer of the upper blades, and they are symmetrically arranged.

[0080] The guide vanes 32 of the inner layer of the upper vanes are arranged in a radial pattern that is inclined upward.

[0081] Through these design requirements, the upper blades 13 redirect the flow of the molten aluminum at the top, forming a complex circulating flow field and preventing Si, Fe, and Mn particles from concentrating at the top. Furthermore, the stirring process does not damage the top coating and oxide layer, ensuring that the molten aluminum is not subject to secondary contamination. Through the special flow field design, Si, Fe, and Mn particles processed in the bottom and middle sections are further evenly dispersed at the top, avoiding local concentration differences and enhancing the stirring effect on the entire molten aluminum pool.

[0082] Preferably, the stirring paddle is configured to have a heat-resistant alloy steel body and a nitrided surface, which can enhance surface hardness and anti-adhesion properties, prevent Si, Fe, and Mn particles from adhering, and ensure that the stirring effect is not affected.

[0083] The protrusions 14 in this embodiment are used to further disrupt the flow of the aluminum liquid, and can be implemented using circular protrusions with a diameter of 8-10 mm.

[0084] Comparative Example 1: In Comparative Example 1, a high-strength, high-silicon aluminum alloy capable of rapid extrusion was prepared using recycled aluminum scrap. The alloy's composition by weight was Si 4.6%, Mg 0.74%, Cu 0.03%, Mn 0.42%, Cr 0.06%, Fe 0.35%, Sr 0.25%, Zn ≤ 0.25%, Ni ≤ 0.05%, Ti ≤ 0.15%, with the balance being Al. The content of any single impurity element was ≤ 0.05%.

[0085] In step 3, a single stirring paddle is used for rotating jet, and the jet is rotated and stirred only once, and finally the profile of comparative example 1 is obtained by melting, casting and extrusion.

[0086] The remaining implementation steps of this embodiment are the same as those of Example 1.

[0087] Comparative Example 2: In Comparative Example 2, a high-strength, high-silicon aluminum alloy capable of rapid extrusion was prepared using recycled aluminum scrap. The alloy's composition by weight was Si 4.6%, Mg 0.74%, Cu 0.03%, Mn 0.42%, Cr 0.06%, Fe 0.35%, Sr 0.25%, Zn ≤ 0.25%, Ni ≤ 0.05%, Ti ≤ 0.15%, with the balance being Al. The content of any single impurity element was ≤ 0.05%.

[0088] In step 5, a standard grade of aluminum titanium boron (Al-TiB) filament grain refiner was added to the launder during the transfer process. The TiAl3 particles were sized between 35 and 45 μm and were unevenly distributed within the Al-TiB filament. Under a metallographic microscope, the TiAl3 particles were unevenly distributed within the Al-TiB filament, with dense particles in the center and sparse particles near the outer surface. The melt was then sequentially passed through an online degassing and filtration device using a two-stage ceramic foam filter plate to obtain a melt. Finally, an aluminum rod was obtained and extruded and aged to produce the profile of Comparative Example 2.

[0089] The remaining implementation steps of this comparative example are the same as those of Example 1.

[0090] Comparative Example 3: In Comparative Example 3, a high-strength, high-silicon aluminum alloy capable of rapid extrusion was prepared using recycled aluminum scrap. The alloy's composition by weight was Si 4.6%, Mg 0.74%, Cu 0.03%, Mn 0.42%, Cr 0.06%, Fe 0.35%, Sr 0.25%, Zn ≤ 0.25%, Ni ≤ 0.05%, Ti ≤ 0.15%, with the balance being Al. The content of any single impurity element was ≤ 0.05%.

[0091] In step six, semi-continuous casting is performed to obtain an aluminum alloy round ingot with a diameter of φ120 mm.

[0092] In step eight, the ingot E is heated to 490° C. and then extruded into a round rod on a 1000T extruder with an extrusion ratio of 41 and an extrusion speed of 5.0 mm / s. After extrusion, the profile is subjected to online water cooling and quenching to obtain the profile of Comparative Example 3.

[0093] The remaining implementation steps of this comparative example are the same as those of Example 1.

[0094] Comparative Example 4: In Comparative Example 4, a high-strength, high-silicon aluminum alloy capable of rapid extrusion was prepared using recycled aluminum scrap. The alloy's composition by weight was Si 4.6%, Mg 0.74%, Cu 0.03%, Mn 0.42%, Cr 0.06%, Fe 0.35%, Sr 0.25%, Zn ≤ 0.25%, Ni ≤ 0.05%, Ti ≤ 0.15%, with the balance being Al. The content of any single impurity element was ≤ 0.05%.

[0095] Step 8: After heating the ingot E to 485°C, the round rod was extruded using an integral die with a welding chamber depth of 20 mm, a working belt length of 0.4 mm, a 1400T machine, an extrusion speed of 7.2 mm / s, and an online water-cooled quenching of the extruded profile to obtain the profile of Comparative Example 4.

[0096] The remaining implementation steps of this comparative example are the same as those of Example 1.

[0097] Comparative Example 5: In Comparative Example 5, a high-strength, high-silicon aluminum alloy capable of rapid extrusion was prepared using recycled aluminum scrap. The alloy's composition by weight was Si 4.6%, Mg 0.74%, Cu 0.03%, Mn 0.42%, Cr 0.06%, Fe 0.35%, Sr 0.25%, Zn ≤ 0.25%, Ni ≤ 0.05%, Ti ≤ 0.15%, with the balance being Al. The content of any single impurity element was ≤ 0.05%.

[0098] Step 8: After heating the ingot E to 480 ° C, it was extruded into an 18 mm round rod. The mold used was a guide die with a specification of φ220*140, wherein the guide plate thickness was 70 mm, the welding chamber depth was 30 mm, the working belt length was 5.0 mm, the machine was selected as 1400T, the extrusion ratio was 70, the extrusion speed was 4.5 mm / s, and the profile was subjected to online water cooling quenching after extrusion to obtain the profile of Comparative Example 5.

[0099] The remaining implementation steps of this comparative example are the same as those of Example 1.

[0100] Comparative Example 6: In Comparative Example 6, a high-strength, high-silicon aluminum alloy capable of rapid extrusion was prepared using recycled aluminum scrap. The alloy's composition by weight was Si 4.6%, Mg 0.74%, Cu 0.03%, Mn 0.42%, Cr 0.06%, Fe 0.35%, Sr 0.25%, Zn ≤ 0.25%, Ni ≤ 0.05%, Ti ≤ 0.15%, with the balance being Al. The content of any single impurity element was ≤ 0.05%.

[0101] Step 8: The ingot E is heated to 490° C. and then extruded into a round rod with an extrusion ratio of 70 and an extrusion speed of 7.5 mm / s. After extrusion, the profile is subjected to strong air cooling quenching to room temperature to obtain the profile of Comparative Example 6.

[0102] The remaining implementation steps of this comparative example are the same as those of Example 1.

[0103] The aluminum alloy profile products obtained in the above-mentioned Example 1 and Comparative Examples 1-6 were subjected to mechanical property tests in accordance with GB / T228.1-2021 "Tensile Test of Metallic Materials Part 1: Room Temperature Test Method", and the deformation of the profiles was checked. The test results are shown in Table 1, where Rm represents tensile strength (MPa), Rp0.2 represents yield strength (MPa), that is, the strength when the non-proportional elongation is 0.2%, and A50 represents elongation after fracture (%), that is, the elongation at a gauge length of 50 mm.

[0104] Table 1 Mechanical properties test results

[0105] According to the test results, the mechanical properties of Example 1 of the present invention are superior to the tensile and yield strength standards of 6XXX aluminum profiles in the national standard. It can be seen that adding an appropriate amount of Mn to the recycled aluminum alloy can effectively neutralize the adverse effects of the Fe element. A unique three-stage stirring paddle is used to stir the aluminum alloy melt, fully breaking up the Fe, Mn, Si and other elements in the melt. A high-grade grain refiner is used to further refine the grains in the round ingot. Increasing the extrusion ratio and designing the working zone to be extremely short, the above measures are used in combination to achieve rapid extrusion and the resulting aluminum profile has high strength.

[0106] See the appearance photos of profile products Figures 16 to 22 .

[0107] In Comparative Example 1, only a single impeller was used for rotary jetting and only one degassing operation, resulting in poor degassing performance compared to a three-paddle system. The dual-paddle system reduced hydrogen content to below 0.1 mL / 100 g within 8-12 minutes, a 30-50% improvement over the traditional single-paddle system (15-20 minutes). Using three impellers for rotary jetting reduces inclusions, improves density, and achieves a high hydrogen removal rate, mitigating the risks of hydrogen embrittlement. Example 1 achieved a 3.9% increase in tensile strength and a 14% increase in elongation compared to Comparative Example 1.

[0108] In Comparative Example 2, ordinary grade grain refiner was selected, and the TiAl3 grains were relatively coarse compared to high grade ones, which did not have a good grain refining effect in the flow channel. As a result, the grains of the profile finally obtained in Comparative Example 2 were not uniform, coarse grains appeared on the surface, and its mechanical properties and elongation were lower than those in Example 1.

[0109] In Comparative Example 3, extrusion was performed on a conventional extruder (1000T). The pressure during the extrusion process was lower than that of 1400T, the degree of metal deformation was smaller, the dislocation density inside the structure was smaller, and the deformation resistance was also smaller, resulting in low mechanical properties in the subsequent tensile test results.

[0110] In Comparative Example 4, the profile is extruded through an integral die, and the aluminum rod flows out of the die hole after a brief deformation, becoming a solid round rod. It does not undergo significant deformation, the internal deformation energy storage is small, the dislocation density is low, and the elemental Si does not undergo the process of deformation and crushing, so the mechanical properties are relatively low.

[0111] In Comparative Example 5, the die working zone is relatively long. During the final process of forming the elemental Si into a round rod, the elemental Si experiences significant frictional deformation with the working zone. Even at slower extrusion speeds, this intense friction can damage the surface and cause cracks. After extrusion in Comparative Example 5, the die working zone exhibits severe damage, and microcracks appear at the bridge. This suggests that when extruding the alloy of the present invention, the working zone should be kept to a minimum to reduce die pressure during the extrusion process.

[0112] Comparative Example 6 uses air cooling quenching, and the cooling rate of its profile is much lower than the water cooling quenching in Example 1. See Table 2 below for details: Table 2 Effect of quenching method on cooling rate

[0113] The mechanical properties of the final profile are lower than those of Example 1. This indicates that when the cooling rate of the alloy is low, the strengthening phase has precipitated and is not completely preserved in the form of a solid solution, resulting in low final mechanical properties after aging.

[0114] In summary, the embodiments of the present invention utilize recycled scrap aluminum as raw material, placing low demands on scrap aluminum sources and recycling equipment, and effectively achieving grade-preserving utilization of recycled aluminum. During the production process, by optimizing the casting process, a unique three-stage stirring paddle is employed to stir the aluminum alloy melt, thoroughly dispersing elements such as Fe, Mn, and Si within the melt for a more uniform distribution within the melt and refining the Si element within the ingot. Furthermore, the use of high-grade TiAl3 wire ensures effective refinement. Air jet degassing significantly removes harmful impurities and hydrogen from the melt. Incorporating a high-temperature superconducting device, the melt is fully homogenized, refining the Si element. Extrusion process parameters are then controlled, with a high extrusion ratio extrusion profile selected to increase extrusion pressure. A guide plate with a bridge is employed to promote grain deformation and breakage. Enhanced welding ensures microstructure density. Finally, the working belt is minimized to reduce outlet pressure and profile temperature rise, ensuring surface quality. The shape and height of the secondary welding chamber are then used to control flow rate. Finally, a high-strength, high-silicon aluminum alloy that can be quickly extruded was produced using recycled scrap aluminum.

[0115] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A method for producing a high-strength, high-silicon aluminum alloy that can be quickly extruded using recycled aluminum scrap, characterized by: include: Step 1: Pre-processing the aluminum waste including crushing and sorting to obtain aluminum material; Step 2: preheating the aluminum material to remove moisture and some organic matter; melting the preheated aluminum material to obtain melt A; Step 3: Refining the melt A, removing slag in the melt A by stirring and skimming; Step 4: Transfer the refined melt A to an alloying furnace and adjust the composition to obtain aluminum alloy melt B; Step 5: Adding AlTiB wire as a grain refiner to the melt B in an amount of 0.1-0.15% of the weight of the melt B; then, performing online degassing and filtration on the melt B to obtain melt C; Step 6: Casting the melt C to obtain an aluminum alloy round ingot D; Step 7: Perform homogenization annealing on the round ingot D, and obtain the aluminum alloy round ingot E after cooling, thereby completing the production and processing of the high-strength and high-silicon aluminum alloy.

2. The method for producing a high-strength, high-silicon aluminum alloy capable of rapid extrusion using recycled aluminum scrap according to claim 1, characterized in that: High-strength and high-silicon aluminum alloy contains the following components in mass percentage: Si 4.0-4.9%, Mg 0.6-0.9%, Cu≤0.1%, Mn 0.36-0.72%, Cr≤0.1%, Fe 0.3-0.6%, Sr0.05-0.4%, Zn≤0.25%, Ni≤0.05%, Ti≤0.15%, the balance is Al; and a single impurity element ≤0.05%; In step 4, the adjustment components are performed with the above components as the target.

3. The method for producing a high-strength, high-silicon aluminum alloy capable of rapid extrusion using recycled aluminum scrap according to claim 1, characterized in that: In step 1, the pretreatment comprises: feeding the aluminum scrap into a crusher for crushing and screening, leaving aluminum-containing fragments with a diameter of less than 110 mm, then removing iron-containing impurities in the aluminum-containing fragments by magnetic separation, then removing non-metallic impurities by eddy current separation, and finally performing X-ray separation and paint stripping to obtain the aluminum material; In step 2, the aluminum material is preheated by placing the aluminum material into a preheating chamber and preheating it to 400-500°C for 20-30 minutes. The preheated aluminum material is then smelted by transferring the preheated aluminum material through a closed passage to a smelting chamber, where the temperature is raised to 700-750°C and melted into liquid aluminum to obtain the melt A. In step 3, the refining process is as follows: adding a refining agent to melt A, and stirring melt A at least twice, each stirring operation is performed at a speed of 300-800 rpm, and the time is 8-12 minutes. After each stirring operation, the melt is allowed to stand for at least 5 minutes, and after standing, the slag in the melt A is removed by skimming; While refining the melt A, an inert gas is continuously introduced into the melting chamber to remove hydrogen in the melting chamber; In step 4, when adjusting the composition of melt A, the temperature of melt A is controlled to be 720-740°C; In step seven, the round ingot D is subjected to homogenization annealing, firstly heated to 550° C. at a heating rate of 90° C. / h, then kept at this temperature for 8 hours, and finally taken out of the furnace and water-cooled to obtain the aluminum alloy round ingot E after cooling.

4. The method for producing a high-strength, high-silicon aluminum alloy capable of rapid extrusion using recycled aluminum scrap according to claim 1, characterized in that: In step 5, the TiAl3 phase in the AlTiB wire is evenly distributed in the AlTiB wire, and the TiAl3 phase density is ≥120 / mm 2 , and the size of each TiAl3 phase is less than 25μm.

5. The method for producing a high-strength, high-silicon aluminum alloy capable of rapid extrusion using recycled aluminum scrap according to claim 1, characterized in that: The method further includes step eight of heating and extruding the round ingot E, and then water-cooling and quenching the ingot online after extrusion to obtain an aluminum profile F; The aluminum profile F is artificially aged at an extrusion speed of 5-7.5 mm / s, with an aging temperature of 175° C. and a heat preservation time of 8 hours to obtain a high-strength and high-silicon aluminum alloy profile.

6. The method for producing a high-strength, high-silicon aluminum alloy capable of rapid extrusion using recycled aluminum scrap according to claim 5, characterized in that: In step eight, during extrusion, the extrusion ratio is controlled within a range of 60-140.

7. The method for producing a high-strength, high-silicon aluminum alloy capable of rapid extrusion using recycled aluminum scrap according to claim 5, characterized in that: In step eight, during extrusion, the extrusion die adopts a guide die design, and the number of diversion bridges is greater than or equal to four, and the thickness of the guide plate D is greater than or equal to ; Depth of welding chamber H= (5~6) ; Wherein the aluminum rod is the round ingot E.

8. The method for producing a high-strength, high-silicon aluminum alloy capable of rapid extrusion using recycled aluminum scrap according to claim 5, characterized in that: In step eight, during extrusion, the length L1 of the die working zone is 2-6 mm, wherein the length L2 of the portion in contact with the aluminum rod is 0.2-0.5 mm, and the rest of the working zone has an inclination angle α of 5-10°.

9. The method for producing a high-strength, high-silicon aluminum alloy capable of rapid extrusion using recycled aluminum scrap according to claim 1, characterized in that: In step 3, the stirring operation is performed using a stirring paddle; The stirring paddle comprises a bottom blade, a middle blade and an upper blade which are spaced apart from each other along the axial direction from bottom to top; The bottom blades serve as propulsion blades for the upward flow of the aluminum liquid, and the blades form an angle of 35-55 degrees with the horizontal plane; The middle blades are variable-section blades, the thickness of each blade gradually decreases from the root to the tip, and a serrated structure is provided on the edge of the blade; a plurality of spiral grooves are provided on the surface of the blade; The upper blade is an anchor blade combination, which has an outer layer and an inner layer; wherein the outer layer is an upward curved arc stirring rod, and the inner layer is a guide blade with convex points.

10. The method for producing a high-strength, high-silicon aluminum alloy capable of rapid extrusion using recycled aluminum scrap according to claim 9, characterized in that: The stirring paddle is made of heat-resistant alloy steel, and the surface of the stirring paddle is nitrided.

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