Method for manufacturing aluminum-lithium alloy solid-phase recycled sheet

Abstract

The present application belongs to the field of metal forming manufacturing and resource recycling, and provides a kind of aluminum lithium alloy solid phase regenerative plate manufacturing method, the process method includes weighing aluminum lithium alloy waste;Aluminum lithium alloy waste after weighing is loaded into extrusion cylinder;Aluminum lithium alloy waste in extrusion cylinder is compacted to obtain blank;Blank is rotated and friction solidified to obtain circular plate;Circular plate is ejected using ejector rod.The present application avoids the problem that active metal lithium is seriously oxidized, burned and even exploded when remelting and recasting, realizes low energy consumption, low cost, high safety and high quality recovery of aluminum lithium alloy waste.At the same time, the tool structure used in the present application is simple, which is convenient for upgrading based on existing general purpose press to carry out waste solid phase regeneration and reduce equipment development cost.The performance of aluminum lithium alloy waste after solid phase regeneration by the present application is equivalent to that of plate obtained by rolling using aluminum lithium alloy ingot.

Description

Technical Field

[0001] This invention belongs to the field of metal forming manufacturing and resource recycling technology, specifically relating to a method for manufacturing aluminum-lithium alloy solid-phase recycled sheet. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Compared to traditional aluminum alloys, aluminum-lithium alloys possess advantages such as high specific strength, high elastic modulus, low density, and good low-temperature performance. Therefore, as a key structural material, they have important applications in aerospace and other fields. Aluminum-lithium alloy billets and components generate a large amount of waste such as chips and powder during subtractive manufacturing processes such as turning, milling, planing, and grinding. Because aluminum-lithium alloys contain the reactive metallic lithium element, lithium is easily oxidized, severely burned, or even exploded during traditional remelting and recasting. Therefore, it is currently impossible to recycle aluminum-lithium alloy waste using conventional processes and technologies, resulting in significant material waste and high production costs.

[0004] Solid-phase regeneration can avoid the element loss problem caused by remelting and casting of waste materials, and is expected to achieve graded recycling and reuse of aluminum-lithium alloy waste. Patent CN202410916354.4 discloses a rotary friction extruder and extrusion forming method. This special rotary friction extruder, employing a complex system including a first fixed beam, a movable beam, an outer slider, a second fixed beam, a first main cylinder, a piercing cylinder, a second main cylinder, a turntable, a central slider, a rotary extrusion rod, an extrusion cylinder, and a positive extrusion rod, can extrude raw materials such as machining chips, metal powders, and mixtures from the extrusion die, thereby forming various profiles with solid or hollow cross-sections and unrestricted length, such as bars, wires, tubes, and profiles. However, this forming equipment and method cannot directly form metal waste into sheet metal, which has extremely wide applications in the aerospace field, such as forming various thin-walled cylinders, sheet metal parts, and skins.

[0005] In addition, as a high-strength aluminum alloy material, aluminum-lithium alloy often suffers from serious problems such as inability to solidify, surface cracking, poor internal welding, low strength and plasticity during the recycling process due to its special alloying elements and hot working characteristics. Currently, the publicly reported process methods still cannot achieve its grade preservation and recycling because the key process parameters and process windows for solid-phase regeneration of aluminum-lithium alloy are not easy to determine. Summary of the Invention

[0006] To address the challenges of recycling aluminum-lithium alloys through smelting and recasting, the complexity and high cost of existing equipment, the inability to obtain sheet metal, and the inability to achieve graded recycling, this invention provides a method for manufacturing solid-phase recycled aluminum-lithium alloy sheets. This method enables low-energy, low-cost, high-safety, and high-quality solid-phase recycling of aluminum-lithium alloy waste.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A first aspect of the present invention provides a method for manufacturing a solid-phase recycled aluminum-lithium alloy sheet, comprising: S1. Weigh the aluminum-lithium alloy scrap; S2. Move the push rod to form a closed space with one end of the extrusion cylinder, and then keep the push rod in the same position. S3. Load the aluminum-lithium alloy waste obtained in step S1 into the extrusion cylinder. S4. The aluminum-lithium alloy scrap in the extrusion cylinder of step S3 is compressed to obtain a billet. The density of the billet is controlled to be above 70% of the density of the aluminum-lithium alloy scrap. The compression is carried out at room temperature by applying pressure to the aluminum-lithium alloy scrap in the extrusion cylinder with an extrusion rod, so that the scrap is compressed under pressure to obtain a billet with a certain initial density and initial shape. The density is calculated based on the mass of the aluminum-lithium alloy scrap and the volume of the billet after compression. S5. The blank obtained in step S4 is subjected to rotary friction curing in the extrusion cylinder; the gap between the extrusion rod and the extrusion cylinder is controlled within 1 mm; the curing temperature is controlled within the range of 400℃ to the melting point of the material; when the curing temperature is 400℃, the extrusion pressure is controlled above 40MPa; when the curing temperature is 500℃, the extrusion pressure is controlled above 35MPa; the specific steps of the rotary friction curing are as follows: a rotating extrusion rod is used to apply pressure to the blank in the extrusion cylinder, and the material is softened and cured by frictional heat and plastic deformation, gradually realizing interface bonding and achieving metallurgical bonding; S6. Move the push rod to eject the formed sheet material.

[0008] Through extensive experiments and long-term research, this invention has discovered that the rotary friction solidification of aluminum-lithium alloy waste can achieve graded recycling of the sheet material through close coordination of three factors: solidification forming temperature, extrusion pressure, and the gap between the extrusion rod and the extrusion cylinder.

[0009] Preferably, the density is any range of 70%-80%, 80%-90%, or "above 90%", and those skilled in the art can select according to the actual working conditions.

[0010] Preferably, the rotation speed is 150-200 r / min and the extrusion speed is 0.25-0.3 mm / min.

[0011] To meet the requirements of solid-phase recycling and forming of aluminum-lithium alloy scrap into sheets, the present invention also provides processing tools and dies配套 with the process. Therefore, in the second aspect of the present invention, there is provided a processing tool and die for solid-phase recycling of aluminum-lithium alloy sheets, including: an extrusion rod, an extrusion cylinder, and a ejector rod. The extrusion rod and the ejector rod are respectively slidably connected to the extrusion cylinder and move towards each other.

[0012] The processing tool and die of the present invention has a simple structure. Based on the existing general-purpose pressure forming equipment for upgrading and transformation, the solid-phase recycling and utilization of metal scrap can be realized, reducing the equipment manufacturing cost and dependence on special equipment.

[0013] In the third aspect of the present invention, there is provided a recycled aluminum-lithium alloy sheet prepared by the above method.

[0014] Advantages of the present invention: (1) The present invention adopts the method of solid-phase recycling to recover aluminum-lithium alloy scrap, without a remelting process, avoiding serious burning loss, oxidation, and explosion of active metal lithium during furnace remelting and casting, and realizing the low-cost and high-safety recycling of aluminum-lithium alloy scrap; (2) The present invention adopts the rotary friction curing process to directly form aluminum-lithium alloy scrap into sheets with a wide range of applications, significantly shortening the process flow and filling the gap that existing recycling process methods cannot obtain sheets; (3) The present invention utilizes frictional heat generation to avoid the preheating process of the blank, effectively reducing production energy consumption; (4) The rotary friction deformation of the present invention promotes grain refinement and oxide crushing, improving the mechanical properties of the sheet; (5) The mechanical properties of the sheet recycled by the method of the present invention are equivalent to those of the sheet obtained by rolling an aluminum-lithium alloy ingot, that is, achieving grade-preserving recycling and utilization; (6) The structure and preparation method of the processing tool and die of the present invention are simple and highly practical, and are easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The attached drawings forming a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0016] Figure 1 It is a schematic flow chart of the manufacturing method for solid-phase recycling and forming of aluminum-lithium alloy scrap into sheets of the present invention; Figure 2 It is a metallographic structure diagram of the cross-section of a circular sheet formed at a forming temperature of 300 °C in Example 1 of the present invention; Figure 3 It is a metallographic structure diagram of the cross-section of a circular sheet formed at a forming temperature of 400 °C in Example 2 of the present invention; Figure 4 The image shows the metallographic structure of a circular plate formed at a forming temperature of 500℃ in Embodiment 3 of the present invention.

[0017] The components are: 1. aluminum-lithium alloy scrap, 2. extrusion rod, 3. extrusion cylinder, 4. push rod, 5. billet, and 6. round plate. Detailed Implementation

[0018] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0019] As described in the background section, existing conventional processes and technologies are insufficient for the recycling and reuse of aluminum-lithium alloy waste. To address this issue, this invention proposes a method for manufacturing solid-phase recycled aluminum-lithium alloy plates, such as... Figure 1 As shown, it includes: weighing, loading, pressing, rotary friction curing, and ejection.

[0020] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0021] Example 1 Using 2195 aluminum-lithium alloy machining debris as raw material, embodiments of the present invention provide a method for manufacturing solid-phase recycled aluminum-lithium alloy sheets, comprising: S1. Weigh 3.356g of 2195 aluminum-lithium alloy scrap 1 using an analytical balance.

[0022] S2. The 3.356g of 2195 aluminum-lithium alloy scrap 1 obtained in step S1 is loaded into the extrusion cylinder 3 with an inner diameter of Φ30mm.

[0023] S3. The 3.356g of 2195 aluminum-lithium alloy scrap 1 in the extrusion cylinder 3 with an inner diameter of Φ30mm from step S2 is compressed to obtain the billet 5.

[0024] Specifically, at room temperature, an extrusion rod 2 with a diameter of Φ29.39mm is used to extrude aluminum-lithium alloy scrap 1 inside the extrusion cylinder 3, so that the scrap 1 is compressed under pressure.

[0025] Furthermore, according to step S1, the mass of the 2195 aluminum-lithium alloy scrap 1 is 3.356 g, and the average density of the 2195 aluminum-lithium alloy scrap 1 is 2.58 g / cm³. 3 According to the requirement that the density should not be less than 70%, the length of the billet 5 after compression should not exceed 2.6mm. The actual length of the billet 5 after compression is 2.5mm, and the actual density is 73.6%.

[0026] S4. The blank 5 with a density of 73.6% obtained in step S3 is subjected to rotational friction curing to obtain a Φ30mm×2mm circular plate 6.

[0027] S5. The circular plate 6 formed in step S4 is ejected using the ejector pin 4.

[0028] Rotational friction curing conditions: rotational speed of 150 r / min and extrusion speed of 0.25 mm / min.

[0029] During rotary friction curing, the maximum forming temperature is 300℃ and the maximum extrusion pressure is 20MPa.

[0030] Using the above-described method for manufacturing aluminum-lithium alloy solid-phase recycled sheet metal, the metallographic structure of the circular sheet metal 6 formed from recycled aluminum-lithium alloy scrap 1 at a forming temperature of 300℃ is shown in the following diagram. Figure 2 As shown, the results indicate that the aluminum-lithium alloy scrap 1 has been initially formed into a circular plate 6 by the solid-phase regeneration forming method. However, the metallographic structure shows that the circular plate 6 only has a partially solidified area on the upper surface in contact with the extrusion rod 2, while most areas have defects such as uncured, pores, and cracks. Therefore, when the maximum forming temperature is 300℃, the maximum extrusion pressure should be greater than 20MPa.

[0031] Example 2 Using 2195 aluminum-lithium alloy machining debris as raw material, embodiments of the present invention provide a method for manufacturing solid-phase recycled aluminum-lithium alloy sheets, comprising: S1. Weigh 3.367g of 2195 aluminum-lithium alloy scrap 1 using an analytical balance.

[0032] S2. The 3.367g of 2195 aluminum-lithium alloy scrap 1 obtained in step S1 is loaded into the extrusion cylinder 3 with an inner diameter of Φ30mm.

[0033] S3. The 3.367g of 2195 aluminum-lithium alloy scrap 1 in the extrusion cylinder 3 with an inner diameter of Φ30mm from step S2 is compressed to obtain the billet 5.

[0034] Specifically, at room temperature, an extrusion rod 2 with a diameter of Φ29.39mm is used to extrude aluminum-lithium alloy scrap 1 inside the extrusion cylinder 3, so that the scrap 1 is compressed under pressure.

[0035] Furthermore, according to step S1, the mass of the 2195 aluminum-lithium alloy scrap 1 is 3.367 g, and the average density of the 2195 aluminum-lithium alloy scrap 1 is 2.58 g / cm³. 3According to the requirement that the density should not be less than 70%, the length of the billet 5 after compression should not exceed 2.6mm. The actual length of the billet 5 after compression is 2.5mm, and the actual density is 73.9%.

[0036] S4. The blank 5 with a density of 73.9% obtained in step S3 is subjected to rotational friction curing to obtain a circular plate 6 with a diameter of 30mm × 2mm.

[0037] S5. The circular plate 6 formed in step S4 is ejected using the ejector pin 4.

[0038] Rotational friction curing conditions: rotational speed of 175 r / min and extrusion speed of 0.25 mm / min.

[0039] During rotary friction curing, the maximum forming temperature is 400℃ and the maximum extrusion pressure is 40MPa.

[0040] Using the above-described method for manufacturing aluminum-lithium alloy solid-phase recycled sheet metal, the metallographic structure of the circular sheet metal 6 formed from recycled aluminum-lithium alloy scrap 1 at a forming temperature of 400℃ is shown in the following figure. Figure 3 As shown, the results indicate that with the increase of forming temperature, the solidified area of ​​the circular plate 6 increases significantly, the pore defects are eliminated, and most areas have achieved metallurgical bonding. However, some areas still have obvious crack defects. Therefore, when the maximum forming temperature is 400℃, the maximum extrusion pressure should be greater than 40MPa.

[0041] Example 3 Using 2195 aluminum-lithium alloy machining debris as raw material, embodiments of the present invention provide a method for manufacturing solid-phase recycled aluminum-lithium alloy sheets, comprising: S1. Weigh 3.359g of 2195 aluminum-lithium alloy scrap 1 using an analytical balance.

[0042] S2. The 3.359g of 2195 aluminum-lithium alloy scrap 1 obtained in step S1 is loaded into the extrusion cylinder 3 with an inner diameter of Φ30mm.

[0043] S3. The 3.359g of 2195 aluminum-lithium alloy scrap 1 in the extrusion cylinder 3 with an inner diameter of Φ30mm from step S2 is compressed to obtain the billet 5.

[0044] Specifically, at room temperature, an extrusion rod 2 with a diameter of Φ29.93mm is used to extrude aluminum-lithium alloy scrap 1 inside the extrusion cylinder 3, so that the scrap 1 is compressed under pressure.

[0045] Furthermore, according to step S1, the mass of the 2195 aluminum-lithium alloy scrap 1 is 3.359 g, and the average density of the 2195 aluminum-lithium alloy scrap 1 is 2.58 g / cm³. 3According to the requirement that the density should not be less than 70%, the length of the billet 5 after compression should not exceed 2.6mm. The actual length of the billet 5 after compression is 2.5mm, and the actual density is 73.7%.

[0046] S4. The blank 5 with a density of 73.7% obtained in step S3 is subjected to rotational friction curing to obtain a circular plate 6 with a diameter of 30mm × 2mm.

[0047] S5. The circular plate 6 formed in step S4 is ejected using the ejector pin 4.

[0048] Rotational friction curing conditions: rotational speed of 200 r / min and extrusion speed of 0.25 mm / min.

[0049] During rotary friction curing, the maximum forming temperature is 500℃ and the maximum extrusion pressure is 35MPa.

[0050] Using the above-described method for manufacturing aluminum-lithium alloy solid-phase recycled sheet metal, the metallographic structure of the circular sheet metal 6 formed from recycled aluminum-lithium alloy scrap 1 at a forming temperature of 500℃ is shown in the following diagram. Figure 4 As shown, the results indicate that with a further increase in forming temperature to 500℃, most areas of the circular plate 6 cross-section have achieved metallurgical bonding. The area near the extrusion rod 2 in the circular plate 6 is free of pores, uncured areas, and cracks. Only a small number of cracks exist at the bottom of the circular plate 6, indicating good overall curing performance. After removing the cracked area at the bottom of the circular plate 6, a tensile test revealed a yield strength of approximately 300 MPa, a tensile strength of approximately 410 MPa, and an elongation at break of approximately 10%. The performance achieved by the waste material after solid-phase regeneration according to this invention is comparable to that of plates obtained by rolling aluminum-lithium alloy ingots. Therefore, when the maximum forming temperature is 500℃, the maximum extrusion pressure should be greater than or equal to 35 MPa.

[0051] It is important to note that Figure 1 This is a schematic diagram of the process, although Figure 1 The extrusion rod 2 and the extrusion cylinder 3 are arranged vertically, but the process method of the present invention has no restrictions on the arrangement of the extrusion rod 2 and the extrusion cylinder 3, that is, both vertical extrusion and horizontal extrusion are applicable.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for manufacturing a solid-phase recycled aluminum-lithium alloy sheet, characterized in that, include: S1. Weigh the aluminum-lithium alloy scrap; S2. Move the push rod to form a closed space with one end of the extrusion cylinder, and then keep the push rod in the same position. S3. Load the aluminum-lithium alloy waste obtained in step S1 into the extrusion cylinder. S4. The aluminum-lithium alloy scrap in the extrusion cylinder of step S3 is compressed to obtain a billet. The density of the billet is controlled at 70%-80% of the density of the aluminum-lithium alloy scrap. S5. The blank obtained in step S4 is subjected to rotary friction curing in the extrusion cylinder. The gap between the extrusion rod and the extrusion cylinder is controlled within 1 mm. When the curing temperature is 500℃, the extrusion pressure is controlled above 35 MPa. The specific steps of the rotary friction curing are as follows: the extrusion rod is used to apply pressure to the blank in the extrusion cylinder. Based on frictional heat generation and plastic deformation, the material is softened and cured, and the interface bonding is gradually realized to achieve metallurgical bonding. The rotational speed is 175-200 r / min, and the extrusion speed is 0.25-0.3 mm / min; S6. Move the push rod to eject the formed sheet material.

2. The method for manufacturing aluminum-lithium alloy solid-phase recycled sheet material as described in claim 1, characterized in that, The pressing is achieved by applying pressure to the aluminum-lithium alloy scrap inside the extrusion cylinder using an extrusion rod at room temperature, thereby pressing the scrap under pressure to obtain a billet with a certain initial density and initial shape.

3. The method for manufacturing aluminum-lithium alloy solid-phase recycled plates as described in claim 1, characterized in that, The density of the billet is calculated based on the mass of the aluminum-lithium alloy scrap and the volume of the billet after compaction.

4. The recycled aluminum-lithium alloy sheet prepared by the method according to any one of claims 1-3.

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