Manufacturing method of aluminum-lithium alloy solid-phase regenerated plate

Abstract

The invention belongs to the field of metal forming manufacturing and resource regeneration recycling, and provides an aluminum-lithium alloy solid-phase regenerated plate manufacturing method which comprises the following steps: weighing aluminum-lithium alloy waste; the weighed aluminum-lithium alloy waste is loaded into an extrusion cylinder; the aluminum-lithium alloy waste in the extrusion cylinder is pressed to obtain a blank; performing rotary friction curing on the blank to obtain a circular plate; and the circular plate is ejected by the ejector rod. According to the method, the problems of serious oxidation, burning loss and even explosion of active metal lithium during remelting, smelting and recasting are avoided, and low-energy-consumption, low-cost, high-safety and high-quality recycling of the aluminum-lithium alloy waste is achieved. And meanwhile, the tool mold used in the method is simple in structure, modification and upgrading based on an existing universal press machine are facilitated for waste solid phase regeneration, and the equipment development cost is reduced. The performance of the aluminum-lithium alloy waste after solid phase regeneration is equivalent to that of a plate obtained by rolling an aluminum-lithium alloy cast ingot.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal forming manufacturing and resource recycling and reuse, and particularly relates to a method for manufacturing solid-phase recycled aluminum-lithium alloy plates. Background Art

[0002] Disclosing the information of this background art section is only intended to increase the understanding of the overall background of the present invention, and is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Compared with traditional aluminum alloys, aluminum-lithium alloys have the advantages of high specific strength, high elastic modulus, low density, and good low-temperature service performance. Therefore, as key structural materials, they have important applications in the fields of aviation, aerospace, etc. A large amount of waste materials such as chips and powders are generated during the subtractive manufacturing processes of aluminum-lithium alloy blanks and components, such as turning, milling, planing, and grinding. Since the aluminum-lithium alloy contains the active metal lithium element, during traditional remelting and casting, the lithium element is prone to oxidation, serious burning loss, and even explosion. Therefore, at present, it is impossible to realize the recycling and reuse of aluminum-lithium alloy waste through conventional process methods and technical routes, resulting in serious material waste and high production costs.

[0004] Solid-phase recycling can avoid the element burning loss problem caused by remelting and casting of waste materials, and is expected to realize the grade-preserving recycling and reuse of aluminum-lithium alloy waste. Patent CN202410916354.4 discloses a rotary friction extrusion machine and an extrusion forming method. By using a special rotary friction extrusion machine with 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 center slider, a rotary extrusion rod, an extrusion cylinder, a forward extrusion rod, etc., raw materials such as machining chips, metal powders, and mixtures can be extruded from the extrusion die, thereby forming various profiles with solid or hollow cross-sections and unlimited length directions, such as bars, wires, tubes, profiles, etc. However, this forming equipment and method cannot directly form metal waste into plates, while plates have extremely wide applications in the fields of aviation and aerospace, such as for forming various thin-walled cylinders, sheet metal parts, skins, etc.

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

[0006] In view of the problems that it is difficult to recycle existing aluminum-lithium alloys by melting and remelting, and the existing equipment has a complex structure, high manufacturing cost, inability to obtain plates, and inability to achieve grade-preserving recycling, etc., the present invention provides a method for manufacturing a solid-phase recycled plate of aluminum-lithium alloy, realizing the low-energy-consumption, low-cost, high-safety, and high-quality solid-phase recycling of aluminum-lithium alloy waste.

[0007] To achieve the above object, the present invention adopts the following technical solutions: In a first aspect of the present invention, there is provided a method for manufacturing a solid-phase recycled plate of aluminum-lithium alloy, comprising: S1. Weigh the aluminum-lithium alloy waste. S2. Move the ejector rod to form a closed space with one end of the extrusion cylinder, and then keep the position of the ejector rod unchanged. S3. Load the aluminum-lithium alloy waste obtained in step S1 into the extrusion cylinder. S4. Compact the aluminum-lithium alloy waste in the extrusion cylinder in step S3 to obtain a blank, and the density of the blank is controlled to be more than 70% of the density of the aluminum-lithium alloy waste; the compaction is to apply pressure to the aluminum-lithium alloy waste in the extrusion cylinder by an extrusion rod at room temperature so that the waste is compacted under the action of the pressure to obtain a blank with a certain initial density and initial shape; the density is calculated according to the mass of the aluminum-lithium alloy waste and the volume of the blank after compaction. S5. Rotationally friction-cure the blank obtained in step S4 in the extrusion cylinder; the gap between the adopted extrusion rod and the extrusion cylinder is controlled within 1 mm; the curing and forming temperature is controlled within the range of 400°C to the melting point of the material; when the curing and forming temperature is 400°C, the extrusion pressure is controlled above 40 MPa; when the curing and forming temperature is 500°C, the extrusion pressure is controlled above 35 MPa; the specific steps of the rotational friction curing are to apply pressure to the blank in the extrusion cylinder by a rotating extrusion rod, and based on frictional heat generation and plastic deformation, soften and cure the material, gradually realize interfacial bonding, and achieve metallurgical bonding. S6. Move the ejector rod to eject the formed plate.

[0008] Through a large number of experiments and long-term research, the present invention has found that for the rotational friction curing of aluminum-lithium alloy waste, the grade-preserving recycling of the plate can be realized through the close cooperation among the curing and forming temperature, the extrusion pressure, and the gap between the extrusion rod and the extrusion cylinder.

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

[0010] Preferably, the rotational 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 waste into plates, the present invention also provides processing tools and dies that match the process. Therefore, in the second aspect of the present invention, a processing tool and die for solid-phase recycling of aluminum-lithium alloy plates are provided, 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 have a simple structure. Based on the existing general-purpose pressure forming equipment, upgrading and transformation can realize the solid-phase recycling and utilization of metal waste, reducing the equipment manufacturing cost and dependence on special equipment.

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

[0014] Beneficial effects of the present invention: (1) The present invention adopts a solid-phase recycling method to recover aluminum-lithium alloy waste. Without a remelting process, it avoids serious burning loss, oxidation, and explosion of active metal lithium during remelting and casting, realizing low-cost and high-safety recovery of aluminum-lithium alloy waste; (2) The present invention uses a rotary friction solidification process to directly form aluminum-lithium alloy waste into plates with a wide range of applications, significantly shortening the process flow and making up for the gap that existing recycling process methods cannot obtain plates; (3) The present invention uses friction to generate heat 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 fragmentation, improving the mechanical properties of the plate; (5) The mechanical properties of the plates recycled by the method of the present invention are equivalent to those of the plates obtained by rolling aluminum-lithium alloy ingots, that is, achieving grade-preserving recycling and utilization; (6) The processing tool and die structure and preparation method of the present invention are simple, highly practical, and easy to promote. Description of the Drawings

[0015] The schematic diagram of the manufacturing method process of the solid-phase recycling and forming of aluminum-lithium alloy waste into plates of the present invention is 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 diagram of the process flow of the manufacturing method of the solid-phase recycling and forming of aluminum-lithium alloy waste into plates of the present invention; Figure 2 It is a metallographic structure diagram of the cross-section of a circular plate 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 plate formed at a forming temperature of 400 °C in Example 2 of the present invention; Figure 4 This is the metallographic structure diagram of the cross-section of a circular plate formed at a forming temperature of 500°C in Example 3 of the present invention.

[0017] Among them: 1. Aluminum-lithium alloy waste, 2. Extrusion rod, 3. Extrusion cylinder, 4. Ejector rod, 5. Blank, 6. Circular plate. Specific implementation mode

[0018] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0019] As described in the background art, it is difficult to recycle aluminum-lithium alloy waste by existing conventional process methods and technical routes. To solve the above problems, the present invention proposes a method for manufacturing aluminum-lithium alloy solid-phase recycled plates, as Figure 1 shown, including: weighing, loading, pressing, rotational friction curing, and ejecting.

[0020] The following will further elaborate on the present invention in conjunction with specific embodiments. It should be noted that the specific embodiments are interpretations rather than limitations of the present invention.

[0021] Example 1 Taking 2195 aluminum-lithium alloy machining chips as raw materials, an embodiment of the present invention provides a method for manufacturing aluminum-lithium alloy solid-phase recycled plates, including: S1. Weigh 3.356 g of 2195 aluminum-lithium alloy chips 1 using an analytical balance.

[0022] S2. Load the 3.356 g of 2195 aluminum-lithium alloy chips 1 obtained in step S1 into an extrusion cylinder 3 with an inner diameter of Φ30 mm.

[0023] S3. Press the 3.356 g of 2195 aluminum-lithium alloy chips 1 in the extrusion cylinder 3 with an inner diameter of Φ30 mm in step S2 to obtain a blank 5.

[0024] Specifically, at room temperature, use an extrusion rod 2 with a diameter of Φ29.39 mm to extrude the aluminum-lithium alloy chips 1 in the extrusion cylinder 3, so that the chips 1 are pressed under the action of pressure.

[0025] Furthermore, according to the mass of the 2195 aluminum-lithium alloy chips 1 measured in step S1 being 3.356 g, and the average density of the 2195 aluminum-lithium alloy chips 1 being 2.58 g / cm 3 , according to the requirement that the relative density is not less than 70%, calculate that the length of the blank 5 after pressing cannot exceed 2.6 mm. The actual length of the blank 5 after pressing is 2.5 mm, and the actual relative density is 73.6%.

[0026] S4. Rotate and frictionally solidify the blank 5 with a relative density of 73.6% obtained in step S3 to obtain a circular plate 6 with a diameter of Φ30 mm and a thickness of 2 mm.

[0027] S5. Push out the circular plate 6 formed in step S4 using the ejector rod 4.

[0028] The conditions for rotational friction solidification are as follows: the rotational speed is 150 r / min, and the extrusion speed is 0.25 mm / min.

[0029] During rotational friction solidification, the maximum forming temperature is 300 °C, and the maximum extrusion pressure is 20 MPa.

[0030] Using the above manufacturing method for solid-phase recycled forming of aluminum-lithium alloy plates, when the forming temperature is 300 °C, the metallographic structure diagram of the cross-section of the circular plate 6 formed by recycling the aluminum-lithium alloy chips 1 is as shown in Figure 2 As shown, the results indicate that the aluminum-lithium alloy chips 1 have been preliminarily formed into a circular plate 6 through the manufacturing method of solid-phase recycled forming of plates. However, the metallographic structure shows that only a partial solidified area exists on the upper surface of the circular plate 6 in contact with the extrusion rod 2, and there are defects such as non-solidified areas, holes, and cracks in most areas. Therefore, when the maximum forming temperature is 300 °C, the maximum extrusion pressure should be greater than 20 MPa.

[0031] Example 2 Using the machined chips of 2195 aluminum-lithium alloy as raw materials, an embodiment of the present invention provides a manufacturing method for solid-phase recycled aluminum-lithium alloy plates, including: S1. Weigh 3.367 g of 2195 aluminum-lithium alloy chips 1 using an analytical balance.

[0032] S2. Load the 3.367 g of 2195 aluminum-lithium alloy chips 1 obtained in step S1 into an extrusion cylinder 3 with an inner diameter of Φ30 mm.

[0033] S3. Compact the 3.367 g of 2195 aluminum-lithium alloy chips 1 in the extrusion cylinder 3 with an inner diameter of Φ30 mm obtained in step S2 to obtain a blank 5.

[0034] Specifically, at room temperature, use an extrusion rod 2 with a diameter of Φ29.39 mm to extrude the aluminum-lithium alloy chips 1 in the extrusion cylinder 3, so that the chips 1 are compacted under the action of pressure.

[0035] Furthermore, according to the mass of the 2195 aluminum-lithium alloy chips 1 measured in step S1, which is 3.367 g, the average density of the 2195 aluminum-lithium alloy chips 1 is 2.58 g / cm 3, according to the requirement that the density is not less than 70%, it is calculated that the length of the blank 5 after pressing should not exceed 2.6 mm. The actual length of the blank 5 after pressing is 2.5 mm, and the actual density is 73.9%.

[0036] S4. Rotationally friction cure the blank 5 with a density of 73.9% obtained in step S3 to obtain a circular plate 6 with a size of Φ30 mm × 2 mm.

[0037] S5. Push out the circular plate 6 formed in step S4 with the ejector rod 4.

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

[0039] During rotational friction curing, the maximum forming temperature is 400 °C, and the maximum extrusion pressure is 40 MPa.

[0040] Using the above manufacturing method for solid-phase recycled forming plates of aluminum-lithium alloy, when the forming temperature is 400 °C, the metallographic structure diagram of the cross-section of the circular plate 6 formed by recycling the aluminum-lithium alloy chips 1 is as Figure 3 shown. The results show that with the increase of the forming temperature, the cured area of the circular plate 6 increases significantly, the hole defects are eliminated, and metallurgical bonding has been achieved in most areas, but obvious crack defects still exist in some areas. Therefore, when the maximum forming temperature is 400 °C, the maximum extrusion pressure should be greater than 40 MPa.

[0041] Example 3 Using the machined chips of 2195 aluminum-lithium alloy as raw materials, an embodiment of the present invention provides a manufacturing method for solid-phase recycled plates of aluminum-lithium alloy, including: S1. Weigh 3.359 g of 2195 aluminum-lithium alloy chips 1 with an analytical balance.

[0042] S2. Load the 3.359 g of 2195 aluminum-lithium alloy chips 1 obtained in step S1 into the extrusion cylinder 3 with an inner diameter of Φ30 mm.

[0043] S3. Compact the 3.359 g of 2195 aluminum-lithium alloy chips 1 in the extrusion cylinder 3 with an inner diameter of Φ30 mm obtained in step S2 to obtain a blank 5.

[0044] Specifically, at room temperature, use an extrusion rod 2 with a diameter of Φ29.93 mm to extrude the aluminum-lithium alloy chips 1 in the extrusion cylinder 3, so that the chips 1 are compacted under the action of pressure.

[0045] Furthermore, according to the mass of the 2195 aluminum-lithium alloy chips 1 measured in step S1, which is 3.359 g, the average density of the 2195 aluminum-lithium alloy chips 1 is 2.58 g / cm 3, according to the requirement that the density is not less than 70%, it is calculated that the length of the blank 5 after pressing should not exceed 2.6 mm. The actual length of the blank 5 after pressing is 2.5 mm, and the actual density is 73.7%.

[0046] S4. Rotationally friction cure the blank 5 with a density of 73.7% obtained in step S3 to obtain a circular plate 6 with a diameter of Φ30 mm and a thickness of 2 mm.

[0047] S5. Push out the circular plate 6 formed in step S4 with the ejector rod 4.

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

[0049] During rotational friction curing, the maximum forming temperature is 500 °C, and the maximum extrusion pressure is 35 MPa.

[0050] Using the above manufacturing method for solid-phase regenerating and forming aluminum-lithium alloy plates, when the forming temperature is 500 °C, the metallographic structure diagram of the cross-section of the circular plate 6 formed by recycling the aluminum-lithium alloy debris 1 is as Figure 4 shown. The results show that as the forming temperature is further increased to 500 °C, most regions of the cross-section of the circular plate 6 have achieved metallurgical bonding. There are no holes and uncured regions in the region of the circular plate 6 close to the extrusion rod 2, and there are no crack defects. Only a small amount of crack defects exist at the bottom of the circular plate 6. The overall curing effect of the circular plate 6 is good. After cutting off the crack area at the bottom of the circular plate 6, the yield strength of the plate 6 obtained through a tensile test is about 300 MPa, the tensile strength is about 410 MPa, and the elongation at break is about 10%. The performance of the waste material after solid-phase regeneration by the present invention is equivalent to that of the plate obtained by rolling an aluminum-lithium alloy ingot. Therefore, when the maximum forming temperature is 500 °C, the maximum extrusion pressure should be greater than or equal to 35 MPa.

[0051] It should be noted that Figure 1 is a process schematic diagram. Although Figure 1 the extrusion rod 2 and the extrusion cylinder 3 in it are arranged vertically, the process method of the present invention has no restrictive requirements 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 are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for manufacturing a solid-phase recycled sheet of an aluminum-lithium alloy, characterized in that, Including: S1. Weigh the aluminum-lithium alloy waste material; S2. Move the ejector rod to form a closed space with one end of the extrusion cylinder, and then keep the position of the ejector rod unchanged; S3. Load the aluminum-lithium alloy waste material obtained in step S1 into the extrusion cylinder; S4. Compact the aluminum-lithium alloy waste material in the extrusion cylinder in step S3 to obtain a blank, and the density of the blank is controlled to be more than 70% of the density of the aluminum-lithium alloy waste material; S5. Carry out rotational friction curing on the blank obtained in step S4 in the extrusion cylinder. The gap between the extrusion rod and the extrusion cylinder used is controlled within 1 mm, and the curing forming temperature is controlled within the range of 400 °C to the melting point of the material. When the curing forming temperature is 400 °C, the extrusion pressure is controlled above 40 MPa; when the curing forming temperature is 500 °C, the extrusion pressure is controlled above 35 MPa; S6. Move the ejector rod to eject the formed sheet.

2. The manufacturing method of the aluminum-lithium alloy solid-phase recycled sheet according to claim 1, characterized in that, The compaction is carried out at room temperature by applying pressure to the aluminum-lithium alloy waste material in the extrusion cylinder with an extrusion rod, so that the waste material is compacted under the action of pressure to obtain a blank with a certain initial density and initial shape.

3. The manufacturing method of the aluminum-lithium alloy solid-phase recycled sheet according to claim 1, characterized in that, Calculate the density of the blank according to the mass of the aluminum-lithium alloy waste material and the volume of the blank after compaction.

4. The manufacturing method of the aluminum-lithium alloy solid-phase recycled sheet according to claim 1, characterized in that, The density is in any one of the ranges of 70%-80%, 80%-90%, and "more than 90%".

5. The method for manufacturing a solid-phase recycled sheet of an aluminum-lithium alloy according to claim 1, characterized in that, The specific steps of the rotational friction curing are to apply pressure to the blank in the extrusion cylinder with a rotating extrusion rod, and based on frictional heat generation and plastic deformation, the material is softened and cured, and the interfacial bonding is gradually realized to achieve metallurgical bonding.

6. The manufacturing method of the aluminum-lithium alloy solid-phase recycled sheet according to claim 1, characterized in that, The rotational speed is 150-200 r / min, and the extrusion speed is 0.25-0.3 mm / min.

7. A processing die for solid-phase recycled aluminum-lithium alloy sheets, including an extrusion rod, an extrusion cylinder, and an ejector rod. The extrusion rod and the ejector rod are respectively slidably connected to the extrusion cylinder and move towards each other.

8. A recycled aluminum-lithium alloy sheet prepared by the method according to any one of claims 1-7.

Images