A rolling-expanding composite forming method for a 5m grade 2219 aluminum alloy complex profiled section ring

Abstract

The present application belongs to the technical field of ring rolling, and particularly relates to a rolling-expanding composite forming method for a 5m-level 2219 aluminum alloy complex profiled section ring. The method comprises the following steps: blanking, homogenization annealing, pre-forging heating, free forging, flat end face punching, mandrel expanding, oblique surface pre-processing of rectangular ring blank, profiled intermediate blank rolling, profiled section ring rolling, air cooling, stress relief annealing, solid solution quenching, cold expansion, aging treatment, rough machining and size detection. Through two-fire rolling, oblique surface pre-processing, stress relief annealing and cold expansion, the present application realizes high-precision forming of a large-diameter complex profiled section ring with an outer diameter of 5000-5100mm and an ellipticity of less than 3%, the residual stress is uniformly distributed, complete circumferential metal flow lines are formed, the material utilization rate is high, the process stability is strong, and the present application is suitable for large-scale batch production of large structural parts such as fork-shaped rings of space launch vehicle storage tanks.

Description

Technical Field

[0001] This invention belongs to the field of ring rolling technology, and specifically relates to a rolling expansion composite forming method for 5m-grade 2219 aluminum alloy complex irregular cross-section rings. Background Technology

[0002] 2219 aluminum alloy belongs to the Al-Cu series of heat-treatable aluminum alloys. Due to its excellent room temperature, high temperature, and low temperature mechanical properties, good resistance to stress corrosion cracking, and excellent weldability, it is widely used in the aerospace field, especially in key load-bearing components such as fork rings, connecting rings, and transition rings in the structure of large launch vehicle propellant tanks. With the development of my country's aerospace industry towards large launch vehicles and deep space exploration, the structure of launch vehicle propellant tanks is evolving towards larger diameters, lighter weight, and integrated designs. Large, complex, irregularly shaped cross-section rings with outer diameters reaching 5 meters, such as fork rings, have become key components in the structure of next-generation launch vehicles. These rings typically have complex cross-sectional shapes, large differences in wall thickness, and asymmetrical structures, placing extremely high demands on forming accuracy, microstructure uniformity, residual stress control, and batch consistency.

[0003] Currently, the manufacturing of large aluminum alloy rings mainly relies on free forging, die forging, ring rolling (ring rolling) and their combinations. For rings with relatively simple cross-sectional shapes, existing processes can meet basic forming requirements. However, for 5m-class 2219 aluminum alloy rings with complex irregular cross-sections, existing technologies still have the following prominent problems: 1. Difficulty in controlling forming accuracy: Due to the large outer diameter and complex cross-sectional changes of the rings, the material flow of traditional rectangular ring blanks is uneven during rolling, which easily leads to local underfilling, large deviations in cross-sectional profiles, and difficulty in meeting design requirements in terms of dimensional accuracy; 2. Uneven distribution of residual stress: 2219 aluminum alloy is highly sensitive to the temperature and strain fields during hot working. Existing rolling processes cannot effectively control the stress distribution in the circumferential, radial, and axial directions of large-diameter rings, which easily leads to local stress concentration or excessive overall residual stress, affecting subsequent processing and performance; 3. Insufficient process adaptability: Existing technologies lack complete set of process parameter schemes for large ring rolling mills and large bulging mills, making it difficult to achieve stable, large-scale production.

[0004] To address the aforementioned issues, some patented technologies have explored solutions. For example, Chinese patent CN112828214A proposes a homogenization rolling process for 5-10 meter 2219 aluminum alloy rings. This process combines aging treatment with low-temperature rapid rolling and high-temperature shaping and dynamic recrystallization to refine grains and reduce anisotropy. However, it does not optimize for the forming characteristics of irregular cross-sections. Chinese patent CN108213843A discloses a manufacturing method for 2219 aluminum alloy C-shaped cross-section ring forgings. This method improves material utilization through irregular billet preparation and ring rolling forming, but it does not address rolling parameter control or residual stress regulation strategies for 5-meter-class large rings.

[0005] Therefore, there is an urgent need to develop a complete forming method for complex irregular cross-section ring parts of 2219 aluminum alloy with a diameter of 5m, and to systematically solve the contradiction between forming accuracy, stress control and process stability, so as to meet the high-performance manufacturing requirements of large aerospace structural parts. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides a rolling-expansion composite forming method for 5m-grade 2219 aluminum alloy complex irregular cross-section ring parts. Through two-stage rolling, pre-forming inclined surface design, stress-relief annealing, and coordinated control of cold expansion forming, high-precision forming, uniform residual stress distribution, and complete circumferential metal flow lines of 5m-grade 2219 aluminum alloy complex irregular cross-section ring parts are achieved. At the same time, material utilization and process stability are significantly improved, making it suitable for large-scale mass production of aerospace large structural components.

[0007] The technical solution of this invention is: a method for roll expansion composite forming of a 5m-grade 2219 aluminum alloy complex irregular cross-section ring, comprising the following steps: S1: Billet cutting: Cut the 2219 aluminum alloy ingot into billets as required; S2: Homogenization annealing: The billet is held at 510℃~530℃ for 12~24h and then cooled in the furnace; S3: Pre-forging heating: Heat the billet to 460℃~495℃, and the holding time is determined according to the effective thickness of the billet, which is 2~3 min / mm. S4: Free forging: Upsetting the billet into a disc, controlling the deformation amount ≥45%, the total forging ratio ≥3.5, and the final forging temperature ≥375℃; S5: Flattening the end face and punching: Flatten the end face of the upset billet and use a double-sided punching process with a punch diameter of φ700mm. Return the punched ring billet to the furnace and heat it to 460℃±5℃ for 4~6h. S6: Frame reaming: The ring blank is reamed using a frame to prepare a rectangular ring blank with an outer diameter of φ2200mm, an inner diameter of φ1400mm, and a height of 600mm; S7: Pre-machining of the forming section: The inner ring surface of the rectangular ring blank after the hole is expanded is machined to form a pre-formed inclined surface; S8: Heating of irregular intermediate billet before rolling: Return the rectangular ring billet to the furnace and heat it to 460℃±5℃, hold it for 4~6h, and control the temperature drop into the rolling mill to ≤30℃ during the transfer process after exiting the furnace. S9: Rolling of irregular intermediate billets: Irregular intermediate billets are rolled using a ring rolling mill with an intermediate billet core roll and a main roll. The ring rolling mill with a main roll diameter of φ2000mm is used to roll irregular intermediate billets. The rolling final temperature is controlled to be ≥380℃ to obtain irregular intermediate billets with an outer diameter of φ3200~φ3400mm, an inner diameter of φ2700~φ2800mm, and a height of 600±10mm. S10: Pre-rolling heating of irregular cross-section ring parts: The irregular intermediate billet is returned to the furnace and heated to 460°C±5°C, held for 46 hours, and the temperature rise during the transfer process is controlled to be ≤30°C before rolling. S11: Rolling of irregular cross-section rings: Irregular cross-section rings are rolled using a ring rolling equipment with an irregular cross-section mandrel and a main roll diameter of φ2000mm. The final rolling temperature is controlled to be ≥380℃ to obtain irregular cross-section rings with an outer diameter of φ5000~φ5100mm, an inner diameter of φ4650~φ4800mm, and a height of 630±5mm. S12: Air cooling: Place the rolled irregular cross-section ring flat on the steel frame fixture and air cool to room temperature; S13: Stress-relief annealing: Return the irregular cross-section ring to the furnace and heat it to 350℃, then hold it for 2~4 hours; S14: Solution treatment and quenching: Hold the irregular cross-section ring at 535℃~543℃ for 5~7h, then quench it in warm water at 65℃~85℃, and control the immersion time to ≤10s. S15: Cold expansion forming: The quenched irregular cross-section ring is placed in an expansion forming machine for cold micro-plastic deformation, and the expansion amount is 1.8%~2.2% of the inner diameter of the ring; S16: Aging treatment: The irregular cross-section ring is reheated to 175℃ in the furnace, held for 18 hours, and then air-cooled. S17: Rough machining: Rough turn the upper and lower end faces of the irregular cross-section ring to control the ellipticity and wall thickness difference; S18: Dimension Inspection: Inspect the dimensions of the irregular cross-section ring to ensure that the ellipticity is less than 3%, and complete the preparation of the irregular cross-section ring.

[0008] Furthermore, the specific process of rolling the irregularly shaped intermediate billet in step S9 is as follows: S91: Biting stage: Main roller speed 0.5~0.7rad / s, core roller radial feed speed 0.3~0.5mm / s, upper and lower tapered roller axial feed speed 0mm / s; S92: Rapid diameter expansion rolling stage: main roll speed 0.6~0.8 rad / s, core roll radial feed speed 0.7~0.9 mm / s, upper and lower tapered roll axial feed speed 0 mm / s; S93: Stable rolling stage: main roll speed 0.7~0.9 rad / s, core roll radial feed speed 0.5~0.6 mm / s, upper and lower tapered roll axial feed speed 0 mm / s; S94: Deceleration finishing stage: main roll speed 0.6~0.7 rad / s, core roll radial feed speed 0.35~0.5 mm / s, upper and lower tapered roll axial feed speed 0 mm / s; S95: Rounding stage: Main roller speed 0.4~0.5 rad / s, core roller radial feed speed 0 mm / s, upper and lower tapered roller axial feed speed 0 mm / s.

[0009] Furthermore, the specific process of rolling the irregular cross-section ring in step S11 is as follows: S111: Biting stage: Main roller speed 0.5~0.7rad / s, core roller radial feed speed 0.3~0.5mm / s, upper and lower tapered roller axial feed speed 0mm / s; S112: Rapid expansion rolling stage: main roll speed 0.6~0.8 rad / s, core roll radial feed speed 0.2~0.3 mm / s, upper and lower tapered roll axial feed speed 0 mm / s; S113: Stable rolling stage: main roll speed 0.7~0.9 rad / s, core roll radial feed speed 0.15~0.2 mm / s, upper and lower tapered roll axial feed speed -0.5 mm / s, negative value indicates tapered roll lifting; S114: Deceleration finishing stage: main roll speed 0.6~0.7rad / s, core roll radial feed speed 0.1~0.15mm / s, upper and lower tapered roll axial feed speed -0.5mm / s, negative value indicates tapered roll lifting; S115: Rounding stage: Main roller speed 0.4~0.5 rad / s, core roller radial feed speed 0 mm / s, upper and lower tapered roller axial feed speed 0 mm / s.

[0010] Furthermore, in steps S113 and S114, the rolling force of the upper conical roll is controlled to be ≤15t.

[0011] Furthermore, in steps S9 and S11, the core roller is continuously lubricated by spraying an emulsion mist.

[0012] Furthermore, in step S15, the cold expansion is performed in 3 to 5 stages to gradually expand to the target expansion amount, and after each expansion, the ring is rotated 9° to 11° circumferentially.

[0013] The technical advantages of this invention are as follows: 1. This invention uses a two-stage rolling process, first rolling an irregularly shaped intermediate billet, and then rolling an irregularly shaped cross-section ring. Combined with a pre-processed inclined surface design, this achieves a reasonable pre-distribution of material across complex cross-sections, effectively avoiding excessive deformation of the upper end face or insufficient filling in certain areas during the final rolling stage. 2. This invention incorporates stress-relief annealing after rolling to effectively release residual stress introduced during rolling; a cold expansion forming process is introduced after solution quenching, which stabilizes the ring dimensions and releases residual quenching stress, resulting in a more uniform distribution of residual stress throughout the ring and reducing the risk of deformation during subsequent processing and use; during the rolling stabilization stage, controlling the upward movement of the upper conical roll and limiting the rolling force to ≤15t prevents large-diameter rings from becoming unstable due to excessive axial force in the later stages of rolling, further reducing the generation of uneven stress. 3. This invention employs a continuous emulsion mist spraying method to lubricate and cool the deformation zone of the ring during rolling, forming a stable lubricating film. This effectively inhibits aluminum alloy sticking to the rolls and surface scratches during rolling, and avoids local overheating and grain coarsening of the ring. It is suitable for continuous and stable rolling of large-diameter, irregularly shaped aluminum alloy rings. 4. This invention adopts a composite forming route of "forging + rolling + bulging" instead of the traditional method of "forging + direct machining," significantly reducing the amount of material removed by machining. Through the pre-forming design of the irregularly shaped intermediate billet, the contour of the final irregularly shaped ring is closer to the finished product shape, effectively improving material utilization and making it suitable for large-scale mass production. 5. The composite forming process of rolling + bulging in this invention creates a complete closed circumferential metal flow line within the ring cross-section, avoiding the defects of cutting off the flow line during machining, and improving the mechanical properties and service reliability of the ring.

[0014] The following will provide further explanation in conjunction with the accompanying drawings. Attached Figure Description

[0015] Figure 1 This is a flowchart of a method for the roll expansion composite forming of a 5m-grade 2219 aluminum alloy complex irregular cross-section ring.

[0016] Figure 2 This is a schematic diagram of a rectangular ring blank with a pre-formed inclined surface processed according to the present invention.

[0017] Figure 3 This is a schematic diagram of the rolling process of the irregularly shaped intermediate billet of the present invention.

[0018] Figure 4 This is a schematic diagram of the rolling process of the irregular cross-section ring of the present invention.

[0019] Figure description: 1-Rectangular ring blank, 2-Pre-formed inclined surface, 3-Core roller, 4-Upper conical roller, 5-Lower conical roller, 6-Main roller, 7-Irregularly shaped intermediate blank, 8-Irregularly shaped cross-section ring. Detailed Implementation

[0020] Example 1 like Figures 1-4As shown, the present invention discloses a method for the roll-expansion composite forming of a 5m-grade 2219 aluminum alloy complex irregular cross-section ring, which specifically includes the following steps: S1: Billet cutting: Cut the 2219 aluminum alloy ingot into billets as required; S2: Homogenization annealing: The billet is held at 510℃~530℃ for 12~24h and then cooled in the furnace; S3: Pre-forging heating: Heat the billet to 460℃~495℃, and the holding time is determined according to the effective thickness of the billet, which is 2~3 min / mm. S4: Free forging: Upsetting the billet into a disc, controlling the deformation amount ≥45%, the total forging ratio ≥3.5, and the final forging temperature ≥375℃; S5: Flattening the end face and punching: Flatten the end face of the upset billet and use a double-sided punching process with a punch diameter of φ700mm. Return the punched ring billet to the furnace and heat it to 460℃±5℃ for 4~6h. S6: Frame reaming: The ring blank is reamed using a frame to prepare a rectangular ring blank 1 with an outer diameter of φ2200mm, an inner diameter of φ1400mm, and a height of 600mm; S7: Pre-machining of the forming section: The inner ring surface of the rectangular ring blank 1 after the hole is expanded is machined to form the pre-formed inclined surface 2; S8: Heating of irregular intermediate billet 7 before rolling: Return rectangular ring billet 1 to the furnace and heat it to 460℃±5℃, keep it at that temperature for 4~6h, and control the temperature drop before rolling to ≤30℃ during the transfer process after exiting the furnace. S9: Rolling of irregular intermediate billet 7: Irregular intermediate billet is rolled using a ring rolling mill with intermediate billet core roll and main roll. Irregular intermediate billet 7 is rolled using a ring rolling mill with main roll 6 having a diameter of φ2000mm. The rolling final temperature is controlled to be ≥380℃ to obtain irregular intermediate billet 7 with an outer diameter of φ3200~φ3400mm, an inner diameter of φ2700~φ2800mm, and a height of 600±10mm. S10: Heating of irregular cross-section ring 8 before rolling: Return the irregular intermediate billet 7 to the furnace and heat it to 460°C±5°C, hold it for 46 hours, and control the temperature rise into the rolling mill ≤30°C during the transfer process after exiting the furnace; S11: Rolling of irregular cross-section ring parts: The irregular cross-section ring parts 8 are rolled using a ring rolling equipment with an irregular cross-section mandrel and a main roll 6 with a diameter of φ2000mm. The final rolling temperature is controlled to be ≥380℃ to obtain an irregular cross-section ring part 8 with an outer diameter of φ5000~φ5100mm, an inner diameter of φ4650~φ4800mm, and a height of 630±5mm. S12: Air cooling: Place the rolled irregular cross-section ring 8 flat on the steel frame fixture and air cool to room temperature; S13: Stress-relief annealing: Return the irregular cross-section ring 8 to the furnace and heat it to 350℃, then hold it for 2~4 hours; S14: Solution treatment and quenching: The irregular cross-section ring 8 is kept at 535℃~543℃ for 5~7h, and then quenched in warm water at 65℃~85℃, with the immersion time controlled to be ≤10s. S15: Cold expansion forming: The quenched irregular cross-section ring 8 is placed in an expansion forming machine for cold micro-plastic deformation, and the expansion amount is 1.8%~2.2% of the inner diameter of the ring; S16: Aging treatment: Heat the irregular cross-section ring part 8 back to 175℃, hold for 18 hours, and air cool. S17: Rough machining: Rough turn the upper and lower end faces of the irregular cross-section ring 8 to control the ellipticity and wall thickness difference; S18: Dimension Inspection: Inspect the dimensions of the irregular cross-section ring 8 to ensure that the ellipticity is less than 3%, and complete the preparation of the irregular cross-section ring.

[0021] Furthermore, in step S3, a trolley-type heating furnace is used for heating, with a temperature control accuracy of ±5℃.

[0022] Furthermore, the specific process of rolling the irregular intermediate billet 7 in step S9 is as follows: S91: Biting stage: Main roller 6 rotation speed 0.5~0.7rad / s, core roller 3 radial feed speed 0.3~0.5mm / s, upper cone roller 4 and lower cone roller 5 axial feed speed 0mm / s; S92: Rapid diameter expansion rolling stage: main roll 6 rotation speed 0.6~0.8rad / s, core roll 3 radial feed speed 0.7~0.9mm / s, upper cone roll 4 and lower cone roll 5 cone roll axial feed speed 0mm / s; S93: Stable rolling stage: Main roll 6 rotation speed 0.7~0.9rad / s, core roll 3 radial feed speed 0.5~0.6mm / s, upper cone roll 4 and lower cone roll 5 axial feed speed 0mm / s; S94: Deceleration finishing stage: Main roll 6 rotation speed 0.6~0.7rad / s, core roll 3 radial feed speed 0.35~0.5mm / s, upper cone roll 4 and lower cone roll 5 axial feed speed 0mm / s; S95: Rounding stage: Main roller 6 rotation speed 0.4~0.5rad / s, core roller 3 radial feed speed 0mm / s, upper conical roller 4 and lower conical roller 5 axial feed speed 0mm / s.

[0023] Furthermore, the specific process of rolling the irregular cross-section ring 8 in step S11 is as follows: S111: Biting stage: Main roller 6 rotation speed 0.5~0.7rad / s, core roller 3 radial feed speed 0.3~0.5mm / s, upper cone roller 4 and lower cone roller 5 axial feed speed 0mm / s; S112: Rapid diameter expansion rolling stage: main roll 6 rotation speed 0.6~0.8 rad / s, core roll 3 radial feed speed 0.2~0.3 mm / s, upper cone roll 4 and lower cone roll 5 axial feed speed 0 mm / s; S113: Stable rolling stage: Main roll 6 speed 0.7~0.9 rad / s, core roll 3 radial feed speed 0.15~0.2 mm / s, upper cone roll 4 and lower cone roll 5 axial feed speed -0.5 mm / s, negative value indicates cone roll lifting; S114: Deceleration finishing stage: Main roll 6 speed 0.6~0.7rad / s, core roll 3 radial feed speed 0.1~0.15mm / s, upper cone roll 4 and lower cone roll 5 axial feed speed -0.5mm / s, negative value indicates cone roll lifting; S115: Rounding stage: Main roller 6 rotation speed 0.4~0.5rad / s, core roller 3 radial feed speed 0mm / s, upper cone roller 4 and lower cone roller 5 axial feed speed 0mm / s.

[0024] Furthermore, in steps S113 and S114, the rolling force of the upper conical roll is controlled to be ≤15t.

[0025] Furthermore, in steps S9 and S11, the core roller 3 is continuously lubricated by spraying emulsion mist.

[0026] Furthermore, in step S15, the cold expansion is performed in 3 to 5 stages to gradually expand to the target expansion amount, and after each expansion, the ring is rotated 9° to 11° circumferentially.

[0027] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for roll expansion composite forming of a 5m-grade 2219 aluminum alloy complex irregular cross-section ring, characterized in that: Includes the following steps: S1: Billet cutting: Cut the 2219 aluminum alloy ingot into billets as required; S2: Homogenization annealing: The billet is held at 510℃~530℃ for 12~24h and then cooled in the furnace; S3: Pre-forging heating: Heat the billet to 460℃~495℃, and the holding time is determined according to the effective thickness of the billet, which is 2~3 min / mm. S4: Free forging: Upsetting the billet into a disc, controlling the deformation amount ≥45%, the total forging ratio ≥3.5, and the final forging temperature ≥375℃; S5: Flattening the end face and punching: Flatten the end face of the upset billet and use a double-sided punching process with a punch diameter of φ700mm. Return the punched ring billet to the furnace and heat it to 460℃±5℃ for 4~6h. S6: Frame expansion: The ring blank is expanded by frame expansion to prepare a rectangular ring blank with an outer diameter of φ2200mm, an inner diameter of φ1400mm, and a height of 600mm (1). S7: Pre-processing of the forming section: The inner ring surface of the rectangular ring blank (1) after the hole is expanded is machined to form a pre-formed inclined surface (2). S8: Heating of irregular intermediate billet (7) before rolling: Return the rectangular ring billet (1) to the furnace and heat it to 460℃±5℃, keep it warm for 4~6h, and control the temperature drop of entering the rolling mill to ≤30℃ during the transfer process after exiting the furnace. S9: Rolling of irregular intermediate billet (7): The irregular intermediate billet is rolled using a ring rolling mill with an intermediate billet core roll and a main roll. The irregular intermediate billet (7) is rolled using a ring rolling mill with a main roll (6) diameter of φ2000mm. The rolling temperature is controlled to be ≥380℃ to obtain an irregular intermediate billet (7) with an outer diameter of φ3200~φ3400mm, an inner diameter of φ2700~φ2800mm, and a height of 600±10mm. S10: Heating of irregular cross-section ring (8) before rolling: Return the irregular intermediate billet (7) to the furnace and heat it to 460°C±5°C, keep it at that temperature for 46 hours, and control the rolling temperature ≤30°C during the transfer process after exiting the furnace; S11: Rolling of irregular cross-section ring (8): The irregular cross-section ring (8) is rolled using a ring rolling equipment with an irregular cross-section core roll and a main roll (6) with a diameter of φ2000mm. The rolling temperature is controlled to be ≥380℃ to obtain an irregular cross-section ring (8) with an outer diameter of φ5000~φ5100mm, an inner diameter of φ4650~φ4800mm, and a height of 630±5mm. S12: Air cooling: Place the rolled irregular cross-section ring (8) flat on the steel frame fixture and air cool to room temperature; S13: Stress-relief annealing: Return the irregular cross-section ring (8) to the furnace and heat it to 350℃, and keep it at that temperature for 2~4 hours; S14: Solution treatment and quenching: The irregular cross-section ring (8) is kept at 535℃~543℃ for 5~7h, and then quenched in warm water at 65℃~85℃, with the immersion time controlled to be ≤10s. S15: Cold expansion forming: The quenched irregular cross-section ring (8) is placed in an expansion forming machine for cold micro-plastic deformation, and the expansion amount is 1.8%~2.2% of the inner diameter of the ring; S16: Aging treatment: The irregular cross-section ring (8) is heated to 175°C in the furnace, kept at that temperature for 18 hours, and then air-cooled. S17: Rough machining: Rough turn the upper and lower ends of the irregular cross-section ring (8) to control the ellipticity and wall thickness difference; S18: Dimension Inspection: Inspect the dimensions of the irregular cross-section ring (8) to ensure that the ellipticity is less than 3% and complete the preparation of the irregular cross-section ring.

2. The method for roll expansion composite forming of a 5m-grade 2219 aluminum alloy complex irregular cross-section ring according to claim 1, characterized in that, In step S3, a trolley-type heating furnace is used for heating, with a temperature control accuracy of ±5℃.

3. The method for roll expansion composite forming of a 5m-grade 2219 aluminum alloy complex irregular cross-section ring according to claim 1, characterized in that, The specific process of rolling the irregular intermediate billet (7) in step S9 is as follows: S91: Biting stage: Main roller (6) rotation speed 0.5~0.7rad / s, core roller (3) radial feed speed 0.3~0.5mm / s, upper cone roller (4) and lower cone roller (5) cone roller axial feed speed 0mm / s; S92: Rapid expansion rolling stage: main roll (6) speed 0.6~0.8rad / s, core roll (3) radial feed speed 0.7~0.9mm / s, upper cone roll (4) and lower cone roll (5) axial feed speed 0mm / s; S93: Stable rolling stage: main roll (6) speed 0.7~0.9rad / s, core roll (3) radial feed speed 0.5~0.6mm / s, upper cone roll (4) and lower cone roll (5) axial feed speed 0mm / s; S94: Deceleration finishing stage: main roll (6) speed 0.6~0.7rad / s, core roll (3) radial feed speed 0.35~0.5mm / s, upper cone roll (4) and lower cone roll (5) axial feed speed 0mm / s; S95: Rounding stage: Main roller (6) speed 0.4~0.5rad / s, core roller (3) radial feed speed 0mm / s, upper cone roller (4) and lower cone roller (5) axial feed speed 0mm / s.

4. The method for roll expansion composite forming of a 5m-grade 2219 aluminum alloy complex irregular cross-section ring according to claim 1, characterized in that, The specific process of rolling the irregular cross-section ring (8) in step S11 is as follows: S111: Biting stage: Main roller (6) speed 0.5~0.7rad / s, core roller (3) radial feed speed 0.3~0.5mm / s, upper cone roller (4) and lower cone roller (5) axial feed speed 0mm / s; S112: Rapid expansion rolling stage: main roll (6) speed 0.6~0.8rad / s, core roll (3) radial feed speed 0.2~0.3mm / s, upper cone roll (4) and lower cone roll (5) axial feed speed 0mm / s; S113: Stable rolling stage: main roll (6) speed 0.7~0.9rad / s, core roll (3) radial feed speed 0.15~0.2mm / s, upper cone roll (4) and lower cone roll (5) axial feed speed of cone roll -0.5mm / s, negative value indicates cone roll lifting; S114: Deceleration finishing stage: main roll (6) speed 0.6~0.7rad / s, core roll (3) radial feed speed 0.1~0.15mm / s, upper cone roll (4) and lower cone roll (5) axial feed speed of cone roll -0.5mm / s, negative value indicates cone roll lifting; S115: Rounding stage: Main roller (6) speed 0.4~0.5rad / s, core roller (3) radial feed speed 0mm / s, upper cone roller (4) and lower cone roller (5) axial feed speed 0mm / s.

5. The method for roll expansion composite forming of a 5m-grade 2219 aluminum alloy complex irregular cross-section ring according to claim 4, characterized in that, In steps S113 and S114, the rolling force of the upper conical roll is controlled to be ≤15t.

6. The method for roll expansion composite forming of a 5m-grade 2219 aluminum alloy complex irregular cross-section ring according to claim 1, characterized in that, In steps S9 and S11, the core roller (3) is continuously lubricated by spraying emulsion mist.

7. The method for roll expansion composite forming of a 5m-grade 2219 aluminum alloy complex irregular cross-section ring according to claim 1, characterized in that, In step S15, the cold expansion is performed in 3 to 5 stages to gradually expand to the target expansion amount, and after each expansion, the ring is rotated 9° to 11° in the circumferential direction.

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