A method for preparing large-size aluminum alloy flat ring

Abstract

The present invention provides a method for producing large-sized aluminum alloy flat rings, comprising heating an aluminum alloy ingot, blanking, expanding, machining, and rolling to produce the large-sized aluminum alloy flat rings. The present invention utilizes appropriate blank sizes and rolling processes to successfully produce large-sized flat rings. The technical solution provided by the present invention can successfully produce large-sized aluminum alloy flat rings exceeding 5 meters in length.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to a method for preparing a large-sized aluminum alloy flat ring. Background Art

[0002] Large-sized aluminum alloy flat rings can be used in transition rings, adapter frames, and flanges for spacecraft such as launch vehicles. These large-sized aluminum alloy flat rings, with an outer diameter of 5.3 meters, feature a high wall-thickness-to-height ratio, making them exceptionally large, ultra-flat rings. These rings are low in height and have a reduced maximum heat-treated thickness, significantly improving performance and offering greater load-bearing capacity than similar rings. However, their production is challenging, exceeding existing domestic rolling specifications, and successful domestic production is rare.

[0003] Currently, there are two common methods for preparing flat rings: horse rack reaming, which directly uses horse rack reaming and flattening to the specifications of the flat ring. This method is extremely difficult to control ovality and is prone to ring size deviations. The large amount of material required results in material waste. Ring rolling, which uses a ring mill for rolling, can better control ovality. However, in order to adapt to the equipment capacity and adjust the high thickness ratio of the rolling, more material is often required. During the rolling process, rolling defects such as roller climbing, bending, and ovality are very likely to occur, resulting in material scrapping. Rolling is extremely difficult, and currently few manufacturers can successfully roll large-sized flat rings.

[0004] The production of flat rings with a height / wall thickness less than 0.5 mm places high demands on equipment and processes, making them prone to warping and folding. During rounding and accelerated rolling, especially accelerated rolling, roll climbing and warping are particularly common, ultimately leading to failure in flat ring production. Unsuccessful ring rolling is primarily due to inappropriate billet dimensions, insufficient equipment capacity, and inappropriate rolling processes. The integrated production of large, flat aluminum alloy rings is crucial, but the large size and complex shape of the components make the production process challenging. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a method for preparing large-sized aluminum alloy flat rings. The method provided by the present invention can successfully roll out large-sized aluminum alloy flat rings.

[0006] The present invention provides a method for preparing a large-sized aluminum alloy flat ring, comprising:

[0007] The aluminum alloy ingot is heated, blanked, expanded, machined and rolled to obtain large-sized aluminum alloy flat rings.

[0008] Preferably, the composition of the aluminum alloy ingot is 2219 aluminum alloy or 7050 aluminum alloy.

[0009] Preferably, the heating temperature is:

[0010] Eutectic temperature of aluminum alloy ingot*(0.90~0.95);

[0011] The holding time of the heating is:

[0012] Maximum thickness of aluminum alloy ingot * heating coefficient;

[0013] The heating coefficient is 1.5 to 3 min / mm.

[0014] Preferably, the blanking is performed by multi-square forging;

[0015] In the process of blanking, the upsetting deformation is 45-70%; the drawing deformation is 20-50%; the upsetting speed is less than 10mm / s; and the drawing pressing speed is less than 25mm / s.

[0016] Preferably, the height of the ring blank during the hole expansion process is:

[0017] Ring blank height = rolling outer diameter change * (0.04 ~ 0.06) + height after rolling;

[0018] The wall thickness of the ring blank during the hole expansion process is:

[0019] Ring blank wall thickness = rolling outer diameter change * (0.04 ~ 0.06) * (0.4 ~ 1) + wall thickness after rolling.

[0020] Preferably, the machining is to machine the inner and outer diameters and the upper and lower end faces of the ring blank; the machining of the inner and outer diameters is to make 60-80% of the inner and outer diameters visible to light, and 20-40% of black skin is allowed to remain; the machining of the upper and lower end faces is to make the upper and lower end faces visible to light, and the single-side turning tool amount is controlled at 2-5mm.

[0021] Preferably, the diameter growth rate during the rolling process is 1 to 5 mm / s; and the outer diameter during the rolling stage is 50 to 180 mm larger than the size of the ring blank.

[0022] Preferably, the rolling includes:

[0023] Adaptation rolling stage, speed-up rolling stage, stable rolling stage, deceleration rolling stage, full-round rolling stage;

[0024] The outer diameter in the adaptive rolling stage is 50 to 180 mm larger than the ring blank size, the change in the speed-up rolling stage accounts for 25 to 40% of the total change in the rolling stage, and the change in the stable rolling stage accounts for 60 to 75% of the total change in the rolling stage.

[0025] Preferably, the outer diameter change in the deceleration rolling stage is 50 to 180 mm, and the outer diameter change in the full-circle rolling stage is 50 to 180 mm;

[0026] The rolling time is 9 to 25 minutes.

[0027] Preferably, the diameter of the large-sized aluminum alloy flat ring is 5000-5500 mm.

[0028] The present invention adopts appropriate billet size and rolling process to successfully roll out large-sized flat rings. The technical solution provided by the present invention can successfully prepare large-sized aluminum alloy flat rings of more than 5 meters. DETAILED DESCRIPTION

[0029] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] The present invention provides a method for preparing a large-sized aluminum alloy flat ring, comprising:

[0031] The aluminum alloy ingot is heated, blanked, expanded, machined and rolled to obtain large-sized aluminum alloy flat rings.

[0032] In the present invention, the composition of the aluminum alloy ingot is preferably 2219 aluminum alloy or 7050 aluminum alloy, which meets the composition requirements of GB / T3190-2020.

[0033] In the present invention, the heating temperature is preferably:

[0034] The low eutectic temperature of aluminum alloy ingot*(0.90~0.95).

[0035] In the present invention, the method for determining the eutectic temperature of the aluminum alloy ingot preferably includes:

[0036] The eutectic temperature of aluminum alloys was determined by DSC.

[0037] In the present invention, the heating holding time is preferably:

[0038] Maximum thickness of aluminum alloy ingot * heating coefficient.

[0039] In the present invention, the heating coefficient is preferably 1.5 to 3 min / mm, more preferably 1.5 to 2.0 min / mm.

[0040] In the present invention, the blanking is preferably carried out by multi-square forging; the upsetting deformation in the blanking process is preferably 45-70%, more preferably 50-65%, and most preferably 55%; the drawing deformation is preferably 20-50%, more preferably 25-40%; the upsetting speed is preferably <10 mm / s, more preferably 4-8 mm / s; the drawing pressing speed is preferably <25 mm / s, more preferably 10-20 mm / s.

[0041] In the present invention, the amount of deformation is preferably controlled during the blanking process to reduce the possibility of large cracks, and the blank is returned to the furnace for heat preservation before punching.

[0042] In the present invention, heating is preferably performed before hole expansion, and the heating temperature and holding time are consistent with those described in the above technical solution and will not be repeated here.

[0043] In the present invention, the height of the ring blank during the hole expansion process is preferably:

[0044] Ring blank height = rolling outer diameter change * (0.04 ~ 0.06) + height after rolling.

[0045] In the present invention, the wall thickness of the ring blank during the hole expansion process is preferably:

[0046] Ring blank wall thickness = rolling outer diameter change * (0.04 ~ 0.06) * (0.4 ~ 1) + wall thickness after rolling.

[0047] In the present invention, the machining is preferably to machine the inner and outer diameters and the upper and lower end faces of the ring blank; the machined inner and outer diameters are preferably 60-80% of the inner and outer diameters are exposed to light, more preferably 65-75%; 20-40% of black skin is allowed to remain, more preferably 25-35%; the machined upper and lower end faces are preferably to be exposed to light; the single-sided turning tool amount is preferably controlled at 2-5 mm, more preferably 3-4 mm.

[0048] In the present invention, the rolling is preferably ring rolling; heating is preferably performed before rolling; the heating temperature and holding time are consistent with those described in the above technical solution and are not repeated here. In the present invention, the diameter growth rate, outer diameter size, wall thickness, height, etc. are preferably controlled at each rolling stage during the rolling process. In the present invention, the diameter growth rate during the rolling process is preferably 1-5 mm / s, more preferably 2-4 mm / s, and most preferably 3 mm / s.

[0049] In the present invention, the rolling preferably includes:

[0050] Adaptation rolling stage, speed-up rolling stage, stable rolling stage, deceleration rolling stage, and full-circle rolling stage.

[0051] In the present invention, the outer diameter of the ring in the adaptive rolling stage is preferably 50 to 180 mm larger than the ring blank size, more preferably 80 to 160 mm. The change in the speed-up rolling stage during the rolling process accounts for 25 to 40% of the total change in the rolling stage, more preferably 30 to 35%; the change in the stable rolling stage accounts for 60 to 75% of the total change in the rolling stage, more preferably 65 to 70%; the change in the outer diameter in the deceleration rolling stage is preferably 50 to 180 mm, more preferably 80 to 160 mm; and the change in the outer diameter in the full-round rolling stage is preferably 50 to 180 mm, more preferably 80 to 160 mm. In the present invention, the rolling time is preferably 9 to 25 minutes, more preferably 15 to 20 minutes.

[0052] In the present invention, the diameter of the large-sized aluminum alloy flat ring is preferably 5000-5500 mm.

[0053] The present invention adopts appropriate billet size and rolling process to successfully roll out large-sized flat rings. Compared with the existing technology, the present invention has a smaller feed amount, which can better control costs, and can ensure ovality through rolling, which can reduce processing allowance.

[0054] Example 1 Preparation of large-size 2219 aluminum alloy flat rings (Φ5340 / Φ4700*140)

[0055] The 2219 ingot with the specification of Φ780×2052mm was selected, the heating system was: 480±10℃, and the billet was kept warm for more than 1200min.

[0056] Multi-sided forging is used: the first upsetting surface is surface A, the first drawing surface is surface B, and the second drawing surface is surface C; the forging parameters are as follows:

[0057]

[0058] Note: Upsetting speed 4.8mm / s, pulling speed 13~18mm / s

[0059] Use a Φ500 punch to punch holes. When the skin is ≤50mm, level it to a height of 490mm. Use a Φ520 blade punch to punch through the skin.

[0060] The heating system before hole expansion is: 480±10℃, the blank (cold material) is kept warm for more than 800min, the hot material is returned to the furnace and the holding time is halved, and the hole is expanded with a Φ500 mandrel to an inner diameter of Φ1200±50mm to ensure uniform wall thickness of the ring, good roundness of the ring blank, and flattening height to 400mm. Use a Φ800 mandrel to continue expanding the hole to an inner diameter of Φ1780±50mm and a flattening height to 310mm.

[0061] Machining is done until the inner and outer diameters are 70% light, 30% black skin is allowed to remain, the height is turned to 300±2mm, and the final ring blank size is Φ2638 / Φ1768*302mm.

[0062] The heating system before ring rolling is: 480±10℃, the billet (cold material) is kept warm for more than 600min, and the holding time of hot material is halved when it returns to the furnace.

[0063] Ring rolling process: The hot size after ring rolling is Φ5429 / Φ4713*160mm, and the size after cooling is Φ5380 / Φ4656*160mm. Flat rings of Φ5340 / Φ4700*140mm can be produced on a six-meter lathe. The rolling time is 16 minutes, and the rolling curve is set as follows:

[0064] Diameter growth rate mm / s Outer diameter (mm) Wall thickness (mm) Height (mm) Ring blank size / 2638 435 302 Adaptation phase 4 2760 420 289 Speed-up phase 5 3540 394 230 Stable phase 5 5200 363 164 deceleration phase 1 5340 360 160 Full circle stage 1 5429 358 160

[0065] Example 2 Preparation of large-size 7050 aluminum alloy flat rings (Φ5380 / Φ4750*130)

[0066] The 7050 ingot with the specification of Φ780×1837mm was selected, the heating system was: 450±10℃, and the billet was kept warm for more than 1200min.

[0067] Multi-sided forging is used: the first upsetting surface is surface A, the first drawing surface is surface B, and the second drawing surface is surface C; the forging parameters are as follows:

[0068]

[0069] Note: Upsetting speed 4.8mm / s, pulling speed 13~18mm / s

[0070] Use a Φ500 punch to punch holes. When the skin is ≤50mm, flatten it to a height of 480mm. Use a Φ520 blade punch to punch through the skin.

[0071] The heating system before hole expansion is: 450±10℃, the blank (cold material) is kept warm for more than 900min, and the hot material is returned to the furnace for half the holding time. Use Φ500 mandrel to expand the hole to the inner diameter of Φ1200±50mm to ensure uniform wall thickness of the ring, good roundness of the ring blank, and flattening height to 400mm. Use Φ800 mandrel to continue expanding the hole to the inner diameter of Φ1880±50mm and the flattening height to 300mm.

[0072] Machining is done until the inner and outer diameters are 70% light, 30% black skin is allowed to remain, the height is turned to 290±2mm, and the final ring blank size is Φ2694 / Φ1872*292mm.

[0073] The heating system before ring rolling is: 450±10℃, the billet (cold material) is kept warm for more than 700min, and the hot material is returned to the furnace and the holding time is halved.

[0074] Ring rolling process: The hot size after ring rolling is Φ5469 / Φ4760*150mm, and the size after cooling is Φ5420 / Φ4710*150mm. Flat rings of Φ5380 / Φ4750*130mm can be produced on a six-meter lathe. The rolling time is 18 minutes, and the rolling curve is set as follows:

[0075] Diameter growth rate mm / s Outer diameter (mm) Wall thickness (mm) Height (mm) Ring blank size / 2694 411 290 Adaptation phase 4 2805 401 278 Speed-up phase 5 3573 383 218 Stable phase 5 5200 359 155 deceleration phase 1 5340 357 150 Full circle stage 1 5469 355 150

[0076] The present invention adopts appropriate billet size and rolling process to successfully roll out large-sized flat rings. Compared with the existing technology, the present invention has a smaller feed amount, which can better control costs, and can ensure ovality through rolling, which can reduce processing allowance.

[0077] Although the present invention has been described and illustrated with reference to specific embodiments of the present invention, these descriptions and illustrations do not limit the present invention. It will be clearly understood by those skilled in the art that, without departing from the true spirit and scope of the present invention as defined by the appended claims, various changes may be made to make specific circumstances, materials, compositions of matter, substances, methods or processes suitable for the object, spirit and scope of the present application. All such modifications are intended to be within the scope of the appended claims. Although the methods disclosed herein have been described with reference to specific operations performed in a specific order, it will be understood that these operations may be combined, subdivided or reordered to form equivalent methods without departing from the teachings of the present invention. Therefore, unless otherwise indicated herein, the order and grouping of operations are not limitations of the present application.

Claims

1. A method for preparing a large-sized aluminum alloy flat ring, comprising: The aluminum alloy ingot is heated, blanked, expanded, machined, and rolled to obtain large-sized aluminum alloy flat rings; The height / wall thickness of the aluminum alloy flat ring is less than 0.5; The blanking is performed by using multi-square forging; The upsetting deformation during the blanking process is 45-70%; the stretching deformation is 20-50%; Upsetting speed <10mm / s; drawing speed <25mm / s; The rolling comprises: Adaptation rolling stage, speed-up rolling stage, stable rolling stage, deceleration rolling stage, full-round rolling stage; The outer diameter of the ring in the adaptive rolling stage is 50 to 180 mm larger than the ring blank size, the change in the speed-up rolling stage accounts for 25 to 40% of the total change in the rolling stage, and the change in the stable rolling stage accounts for 60 to 75% of the total change in the rolling stage; The outer diameter change in the deceleration rolling stage is 50 to 180 mm, and the outer diameter change in the full-round rolling stage is 50 to 180 mm; The rolling time is 9 to 25 minutes.

2. The method according to claim 1, characterized in that The composition of the aluminum alloy ingot is 2219 aluminum alloy or 7050 aluminum alloy.

3. The method according to claim 1, characterized in that The heating temperature is: Eutectic temperature of aluminum alloy ingot*(0.90~0.95); The holding time of the heating is: Maximum thickness of aluminum alloy ingot * heating coefficient; The heating coefficient is 1.5 to 3 min / mm.

4. The method according to claim 1, wherein The height of the ring blank during the hole expansion process is: Ring blank height = rolling outer diameter change * (0.04 ~ 0.06) + height after rolling; The wall thickness of the ring blank during the hole expansion process is: Ring blank wall thickness = rolling outer diameter change * (0.04 ~ 0.06) * (0.4 ~ 1) + wall thickness after rolling.

5. The method according to claim 1, characterized in that The machining is to machine the inner and outer diameters and the upper and lower end faces of the aluminum alloy ring blank; the machining of the inner and outer diameters is to make 60-80% of the inner and outer diameters visible to light, and 20-40% of black skin is allowed to remain; the machining of the upper and lower end faces is to make the upper and lower end faces visible to light, and the single-side turning tool amount is controlled at 2-5mm.

6. The method according to claim 1, characterized in that The diameter growth rate during the rolling process is 1 to 5 mm / s.

7. The method according to claim 1, characterized in that The diameter of the large-sized aluminum alloy flat ring is 5000-5500 mm.

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