Aluminum alloy ultra-large type ring piece lantern ring rolling forming method

Abstract

The invention belongs to the technical field of non-ferrous metal material preparation, and particularly relates to an aluminum alloy ultra-large type ring piece lantern ring rolling forming method which comprises the following steps that (1) a plurality of initial ring pieces which are different in inner diameter and can be sequentially and tightly sleeved together are prepared, and the adjacent sleeved initial ring pieces can be in interference fit; (2) the surface of the initial ring piece is cleaned; (3) the initial ring pieces with the large inner diameter are heated, and the initial ring pieces with the small inner diameter are sleeved with the initial ring pieces, so that the multiple initial ring pieces are tightly arranged together in a sleeving mode, and a middle ring piece is formed; (4) the temperature of the initial ring piece on the outermost layer in the middle ring pieces is controlled to be larger than 130 DEG C, the middle ring pieces are subjected to bulging, the bulging rate ranges from 8% to 9%, the middle ring pieces are cooled to the room temperature, and the ring pieces to be rolled are obtained, and (5) the ring pieces to be rolled are heated to 400-450 DEG C and then rolled, and the aluminum alloy ring pieces are obtained.The ultra-large ring pieces can be prepared, the defects of the ultra-large ring pieces are reduced, and it is guaranteed that the structure is uniform and consistent.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metal material preparation, and in particular relates to a ring-rolling forming method for an aluminum alloy super-large ring. Background Art

[0002] With the advancement of the manufacturing industry, the demand for large forgings is increasing, especially in the aerospace industry. Forged rings are becoming increasingly larger. For example, the diameter of forging rings for rockets has increased from 2.25 meters to 3.35 meters, and now to 5 meters. In the future, the diameter of forging rings for super-heavy rockets may exceed 15 meters, and the weight of such forging rings will increase exponentially. Currently, the weight of a single aluminum alloy ingot that can be forged is only 10 tons. If forging rings over 15 tons are to be forged, the ingot diameter must reach 1500mm. Obviously, casting a 1500mm aluminum alloy ingot is impossible, so aluminum alloy forgings weighing 15 tons have not yet been manufactured in the world.

[0003] Existing aluminum alloy forging technology is highly mature for producing aluminum alloy forged rings with a diameter of less than 5 meters and a weight of less than 5 tons. However, the production of aluminum alloy forged rings with a diameter of 10 meters and a weight of 10 tons is still in the research and trial production stage, and the yield rate is extremely low. Currently, there is no technology capable of producing aluminum alloy forged rings of 15 meters (weighing 15 tons) or even 20 meters (weighing 20 tons). How to produce forged rings with larger diameters and heavier weights than currently possible while still meeting quality standards is a pressing challenge for technicians.

[0004] The primary aluminum alloy grades used in aerospace applications are the 2XXX, 5XXX, and 7XXX series. Within the 2XXX series, only 2219 aluminum alloy can currently produce ingots up to 1300mm in diameter (less than 1250mm after the vehicle's skin). However, this yield is low and the quality is inconsistent. The other 2A14 alloy, commonly used in aerospace, currently has a maximum ingot diameter of no more than 1000mm. Therefore, the maximum forgeable ingot size for 2XXX series aluminum alloys is currently 1250 x 3800mm (13 tons). Meanwhile, 5XXX, 7XXX, aluminum-lithium alloys, and aluminum-based composites, such as 5A06, 7050, and 1420 aluminum alloys, can currently only produce ingots up to 900mm in diameter, with forgeable ingot sizes of 860 x 3000mm (5 tons). Existing ring rolling equipment has a rolling capacity of up to 16 meters. Even with existing ring rolling machines, the weight of the ingots limits the production of aluminum alloy forging rings weighing up to 15 tons, is currently not technologically feasible.

[0005] Patent application number CN202111534804.6 discloses a method for hot rolling forming of large aluminum alloy rings. It adopts a hot rolling forming method for ring construction, but it has the disadvantage that the construction surface is prone to cracking when the ring is rolled after construction, requires a small feed rate, and requires a small amount of deformation each time rolling, and multiple production cycles. This method is inefficient, the quality is difficult to guarantee, and it cannot achieve true industrial production.

[0006] Patent application number CN202310357075.4 discloses a stacking and ring-rolling forming method for thin-walled rings, which is mainly aimed at steel parts, such as high-temperature alloys. Due to the inherent characteristics of steel, if there are looseness, holes or small cracks in the center during forging or ring rolling, they can be healed by deformation. However, due to the inherent physical properties of aluminum alloys and magnesium alloys (the crystal structure is a face-centered cubic structure, and the fluidity during the deformation process is poor), once there are looseness, holes or small cracks in the middle of the forging or ring, they cannot be eliminated by forging or ring rolling deformation. Instead, they will become larger and larger until they are completely cracked. Therefore, this solution is not suitable for aluminum alloys or magnesium alloys. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for forming super-large aluminum alloy rings by ring rolling, which can prepare super-large rings, reduce the defects of super-large rings, and ensure uniform organization.

[0008] The embodiment of the present invention provides a method for forming an aluminum alloy super-large ring by ring rolling, comprising the following steps: 1) preparing a plurality of initial rings having different inner diameters and being able to be tightly fitted together in sequence, with adjacent initial rings being able to have an interference fit; 2) cleaning the surface of the initial ring; 3) heating the initial ring with a larger inner diameter and fitting it onto the initial ring with a smaller inner diameter, thereby fitting the plurality of initial rings tightly together to form an intermediate ring; 4) Control the temperature of the outermost initial ring in the intermediate ring to be greater than 130°C, expand the intermediate ring with a expansion rate of 8-9%, and cool it to room temperature to obtain the ring to be rolled; 5) The ring to be rolled is heated to 400-450°C and then rolled to obtain an aluminum alloy ring.

[0009] Preferably, a plurality of aluminum alloy rings having different inner diameters and capable of being tightly fitted together in sequence are prepared, and adjacent aluminum alloy rings can be interference-fitted; Repeat the above steps 1) to 5) at least once to obtain an aluminum alloy super-large ring.

[0010] Preferably, among the adjacent initial rings, the inner diameter of the initial ring with a larger inner diameter is 1 to 3 mm smaller than the outer diameter of the initial ring with a smaller inner diameter.

[0011] Preferably, the surface roughness of the initial ring is not greater than Ra1.6.

[0012] Preferably, the surface of the initial ring is cleaned by sequentially performing alkali washing, water washing, acid washing, and hot water washing on the initial ring.

[0013] Preferably, the solution used for the alkali washing is a 5-15% sodium hydroxide solution at a temperature of 50-60°C; the solution used for the acid washing is a 20-35% nitric acid solution; and the temperature of the hot water is above 60°C.

[0014] Preferably, before heating the initial ring with a larger inner diameter, the initial ring with a larger inner diameter is completely wrapped with aluminum foil, and then heated after the wrapping is completed.

[0015] Preferably, the heating temperature of the initial ring with a larger inner diameter is 150-200°C.

[0016] Preferably, the ring rolling equipment is a ring rolling machine, which only rolls the wall thickness but not the height direction during the ring rolling.

[0017] Preferably, the feed rate during ring rolling is 1-3 mm / s.

[0018] The present invention has the beneficial effect of combining two, three, or more small initial rings with machined surfaces through interference fit, then subjecting them to expansion forming to bond them together to form a complete ring. The rings are then heated and rolled on a ring rolling machine to increase their diameter. After rolling, the above steps can be repeated, connecting multiple rings together and rolling them again. The number of cycles required is determined by the final size of the ring, ultimately producing a qualified, integrated ring.

[0019] The present invention ensures effective bonding at the intersections of the rings through aluminum foil coating + expansion deformation + cold shrinkage and extrusion, ensuring that no air is left on the surface (or the remaining air is squeezed out), thereby effectively ensuring uniformity of the tissue. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of the two initial ring parts of the present invention being sheathed together.

[0021] Figure 2 This is a schematic structural diagram of the three initial ring components of the present invention being assembled together.

[0022] Figure 3 This is a schematic diagram of the structure of the three initial rings of the present invention after being put together and expanded.

[0023] Figure 4 This is a physical picture of the final aluminum alloy ring after ring rolling.

[0024] Figure 5 This is the ultrasonic testing result of the final aluminum alloy ring. DETAILED DESCRIPTION

[0025] Example 1 A method for forming an aluminum alloy super-large ring by ring rolling includes the following steps: 1) preparing a plurality of initial rings having different inner diameters and being able to be tightly fitted together in sequence, with adjacent initial rings being able to have an interference fit; The size of the initial ring is determined according to the size of the final aluminum alloy super-large ring. This embodiment 1 is described using the final aluminum alloy super-large ring (outer diameter 16 meters, inner diameter 15.7 meters, height 0.8 meters, weight 17 tons) as an example.

[0026] The initial rings can be tightly fitted together in sequence, so the outer diameter of the first ring is approximately equal to the inner diameter of the second ring, and the inner diameter of the third ring is approximately equal to the outer diameter of the second ring. Before the final forming of the initial rings, the dimensions of the initial rings before forming are: the first ring size is Φ5010 (outer diameter) × Φ4790 (inner diameter) × Φ950 (height), the second ring size is Φ5210 × Φ4990 × Φ950, and the third ring size is Φ5410 × Φ5190 × Φ950, in mm, the same below. Machining is then performed to remove surface defects and ensure a surface roughness no greater than Ra1.6. The ring dimensions after machining must follow the principle that the outer diameter of the first ring must be 1mm larger than the inner diameter of the second, and the outer diameter of the second ring must be 1mm larger than the inner diameter of the third. The dimensions of the first ring after machining are Φ5001×Φ4800×Φ902, the second ring Φ5201×Φ5000×Φ902, and the third ring Φ5400×Φ5200×Φ902 (unit: mm). This setting ensures that adjacent initial rings in the set have an interference fit. After machining, ultrasonic testing is performed to ensure that the rings are free of defects, ensuring that the final product meets the requirements. For multiple rings, the dimensions are similar.

[0027] 2) cleaning the surface of the initial ring; The cleaning method is to sequentially perform alkaline washing, water washing, acid washing, and hot water washing on the initial ring. The alkaline washing solution is 5-15% sodium hydroxide solution at a temperature of 50-60°C, and the scrubbing is carried out for 10 minutes. The acid washing solution is 20-35% nitric acid solution, and the scrubbing is carried out for 3-5 minutes. The hot water temperature is above 60°C.

[0028] 3) heating the initial ring with a larger inner diameter and fitting it onto the initial ring with a smaller inner diameter, thereby fitting the plurality of initial rings tightly together to form an intermediate ring; Aluminum alloy expands when heated. Therefore, heating the initial ring with the larger inner diameter increases its inner diameter. Once the inner diameter of the larger initial ring is increased to at least 1 mm, the smaller initial ring can be accommodated within it, allowing the two initial rings to be nested together. After the initial rings cool, they form an interference fit. Generally, the heating temperature for the initial ring with the larger inner diameter is 150-200°C, which causes the ring diameter to deform by approximately 2% due to thermal expansion.

[0029] Before heating the initial ring with a larger inner diameter, completely wrap the initial ring with a larger inner diameter with aluminum foil, and then heat it after wrapping. The purpose of this operation is to prevent oxidation of the aluminum alloy surface during the heating process. The aluminum foil is wrapped in a spiral manner without leaving any gaps. After heating is completed, it is immediately taken out, the aluminum foil is torn off, and then immediately put on the first initial ring.

[0030] By sequentially operating in this manner, three or more initial rings can be nested together. Three rings of the aforementioned dimensions, when nested together, form a complete ring with dimensions of Φ5400mm x Φ4800mm x Φ902mm. The ring's wall thickness has increased, and its weight has also increased by approximately three times, to 12.4 tons.

[0031] 4) Control the temperature of the outermost initial ring in the intermediate ring to be greater than 130°C, expand the intermediate ring with a expansion rate of 8-9%, and cool it to room temperature to obtain the ring to be rolled; The temperature of the outermost initial ring in the intermediate ring is controlled to be greater than 130°C. This control method is to immediately expand the outermost initial ring after all the rings are put together. At this time, the temperature of the outermost initial ring will be greater than 130°C. As the outermost initial ring cools to room temperature, the outermost initial ring will gradually reduce in size by approximately 1% (for example, the three rings of the above dimensions, after being expanded and cooled to room temperature, will have a size of Φ5710mm×Φ5145mm×Φ900mm). This expansion plus outer layer shrinkage method adheres all the rings together and squeezes out the air between the rings, preventing oxidation at the joints during the next ring rolling heating process. This ensures the uniformity of the tissue at the joints after ring rolling and forms a common interface (i.e., tissue uniformity).

[0032] 5) The ring to be rolled is heated to 400-450°C and then rolled to obtain an aluminum alloy ring.

[0033] Ring rolling equipment is a ring rolling machine. Ring rolling only measures wall thickness, not height. The feed rate is 1-3 mm / s. The higher the feed rate, the better. The rings are rolled to the required dimensions. If the weight or size is insufficient, the rings can be rolled to an intermediate size with a 35%-50% deformation. The above steps are then repeated, rolling one or more rings, machining them, then sleeved, bulging, and rolling. Ensure that the final size requirements can be rolled out (for example, the ring of the above size can be first rolled to Φ10010×Φ9700×Φ900, with a ring deformation of 45%, and then rolled into 1 Φ9710×Φ9590×Φ900 and 1 Φ10110×Φ10000×Φ900, and then machined - surface treated - ringed, the size after ringed becomes Φ10100×Φ9600×Φ850, weighing 18.7 tons - bulging - ring rolling, the final size after ring rolling is Φ16010×Φ15700Φ×850, with a ring deformation of 38%, and the ring deformation is finally machined to produce a ring with an outer diameter of 16 meters, an inner diameter of 15.7 meters, a height of 0.8 meters, and a weight of 17 tons, the unit is mm).

[0034] The quality of the final aluminum alloy ring can be tested by ultrasonic testing. A-level ultrasonic testing can be carried out according to GJB1580 standard to confirm whether there are any defects exceeding the standard. Figure 4 As shown, the test results are Figure 5 As shown, the test is qualified.

[0035] This invention overcomes the limitations on the size and quality of the raw material (ingot), enabling the production of ultra-large rings that could only be produced from large ingots. Multiple smaller, higher-quality rings are used as the starting blanks. Ultrasonic testing after machining ensures that the starting blanks are qualified products, with no defects carried over to the final product. This ensures product quality and improves the manufacturing yield rate.

[0036] The present invention realizes defect-free rings. By using aluminum foil wrapping + expansion deformation + cold shrinkage and extrusion, the intersections of the rings are effectively bonded, ensuring that no air is left on the surface (or the remaining air is squeezed out), and effectively ensuring uniform tissue consistency.

[0037] The present invention can be used not only for aluminum alloys, aluminum-lithium alloys, and aluminum-based composite materials, but also for magnesium alloys, titanium alloys and their metal-based composite materials. It can also be used for forming between different materials to realize a new type of ring with three metal materials for the outer diameter, middle part, and inner diameter (such as the inner circle is magnesium alloy, the middle is aluminum alloy, and the outer circle is aluminum-based composite material) as one piece, providing ideas for the subsequent research and development of functional materials.

[0038] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of protection of the present application is limited to these examples. In line with the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0039] The one or more embodiments of this application are intended to encompass all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this application should be included in the scope of protection of this application.

Claims

1. A method for forming an aluminum alloy super-large ring by ring rolling, characterized in that: The following steps are included: 1) preparing a plurality of initial rings having different inner diameters and being able to be tightly fitted together in sequence, with adjacent initial rings being able to have an interference fit; 2) cleaning the surface of the initial ring; 3) heating the initial ring with a larger inner diameter and fitting it onto the initial ring with a smaller inner diameter, thereby fitting the plurality of initial rings tightly together to form an intermediate ring; 4) Control the temperature of the outermost initial ring in the intermediate ring to be greater than 130°C, expand the intermediate ring with a expansion rate of 8-9%, and cool it to room temperature to obtain the ring to be rolled; 5) The ring to be rolled is heated to 400-450°C and then rolled to obtain an aluminum alloy ring.

2. The molding method according to claim 1, wherein: A plurality of aluminum alloy rings with different inner diameters are prepared and can be tightly fitted together in sequence, and adjacent aluminum alloy rings can have an interference fit; Repeat the above steps 1) to 5) at least once to obtain an aluminum alloy super-large ring.

3. The molding method according to claim 1, wherein: Among the adjacent sets of initial rings, the inner diameter of the initial ring with a larger inner diameter is 1 to 3 mm smaller than the outer diameter of the initial ring with a smaller inner diameter.

4. The molding method according to claim 1, wherein: The surface roughness of the initial ring is not greater than Ra1.

6.

5. The molding method according to claim 1, wherein: The surface of the initial ring is cleaned by sequentially performing alkali washing, water washing, acid washing and hot water washing on the initial ring.

6. The molding method according to claim 5, wherein: The solution used for the alkali washing is a 5-15% sodium hydroxide solution at a temperature of 50-60°C; the solution used for the acid washing is a 20-35% nitric acid solution; The temperature of the hot water is above 60°C.

7. The molding method according to claim 1, wherein: Before heating the initial ring with a larger inner diameter, the initial ring with a larger inner diameter is completely wrapped with aluminum foil, and then heated after the wrapping is completed.

8. The molding method according to claim 1, wherein: The heating temperature of the initial ring with a larger inner diameter is 150~200℃.

9. The molding method according to claim 1, wherein: The equipment for rolling rings is a ring rolling machine, which only rolls the wall thickness but not the height direction.

10. The molding method according to claim 9, wherein: The feed rate during ring rolling is 1~3mm / s.

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