Aluminum alloy ring or cylinder ring rolling manufacturing process based on shear strain superposition

Abstract

The invention provides an aluminum alloy ring or barrel part ring rolling manufacturing process based on shear strain superposition. The aluminum alloy ring or barrel part ring rolling manufacturing process specifically comprises the following steps that an aluminum alloy ring or barrel part is preheated; the outer side of the aluminum alloy ring or cylinder piece is heated, the inner side of the aluminum alloy ring or cylinder piece is cooled, and a temperature difference is formed between the outer side and the inner side of the ring or cylinder piece; a driving roller and a core roller are synchronously preheated according to the temperature of the outer side and the inner side of the ring or the cylinder part, and the driving roller and the core roller make contact with and are tangent to the outer side and the inner side of the ring or the cylinder part respectively; setting the linear speeds of the core roller and the driving roller, and ensuring that the linear speed ratio of the driving roller to the core roller is greater than 1; and carrying out thermomechanical treatment on the aluminum alloy ring or cylinder piece. According to the aluminum alloy ring or barrel part ring rolling manufacturing process based on shear strain superposition, the shear strain can be fully utilized in the aluminum alloy ring rolling process, so that the organization structure of the ring or barrel part is greatly improved, and high-strength and high-toughness aluminum alloy ring or barrel part ring rolling manufacturing is achieved.

Description

Technical Field

[0001] This invention belongs to the field of metal material plastic processing technology, specifically relating to a ring rolling manufacturing process for aluminum alloy rings or cylinders based on shear strain superposition. Background Technology

[0002] Aluminum alloy rings or cylinders are key load-bearing components in various aerospace equipment. Their lightweight, high strength, and high toughness are crucial for improving rocket carrying capacity and weapon performance. Ring rolling, due to its continuous, localized, multi-pass rolling deformation characteristics, offers advantages such as labor saving, energy saving, and high efficiency, making it a typical process for the plastic processing of aluminum alloy rings or cylinders. However, existing large aluminum alloy rings or cylinders still suffer from problems in ring rolling forming, including coarse and uneven microstructure, limited second-phase fragmentation, and insufficient strength and toughness, making it difficult to meet the stringent mechanical performance requirements of next-generation aerospace equipment.

[0003] Traditional ring rolling processes induce radial deformation in rings or cylinders through the radial feed motion of the mandrel. The amount of radial deformation is a key process parameter and an important indicator used by designers to improve the microstructure and properties of aluminum alloy rings or cylinders. However, relying solely on radial deformation is insufficient to efficiently induce sufficient dynamic recrystallization in aluminum alloys, resulting in poor grain refinement and difficulty in effectively breaking up coarse second phases. Even with thick-walled aluminum alloy rings or cylinders, small amounts of radial deformation may not penetrate the ring or cylinder, leading to an inhomogeneous microstructure, insufficient strength and toughness, and poor consistency. In contrast, shear strain promotes dislocation slip, easily generating high-density dislocations within the alloy, facilitating sufficient dynamic recrystallization, and efficiently refining the grains. Furthermore, shear strain easily generates multi-directional stress concentration at the interface between the second phase and the matrix, which is beneficial for cutting second-phase particles and effectively breaking up coarse second phases. Despite this, existing aluminum alloy ring rolling processes do not effectively utilize shear strain, resulting in limited improvement in the microstructure of rings or cylinders and a failure to significantly enhance mechanical properties. Summary of the Invention

[0004] The purpose of this invention is to provide a ring rolling manufacturing process for aluminum alloy rings or cylinders based on shear strain superposition, which solves the technical problem of how to make full use of shear strain in the aluminum alloy ring rolling process to significantly improve the microstructure of the ring or cylinder, thereby greatly improving its mechanical properties.

[0005] A ring rolling manufacturing process for aluminum alloy rings or cylinders based on shear strain superposition specifically includes the following steps:

[0006] Step S1: Preheat the aluminum alloy ring or cylinder in a heating furnace;

[0007] Step S2: Remove the aluminum alloy ring or cylinder from the heating furnace, heat the outer side of the aluminum alloy ring or cylinder, and cool the inner side to create a temperature difference between the outer and inner sides of the ring or cylinder.

[0008] Step S3: Based on the temperatures of the outer and inner sides of the ring or cylinder, preheat the drive roller and core roller simultaneously, with the drive roller and core roller respectively in contact with the outer and inner sides of the ring or cylinder.

[0009] Step S4: Set the linear speed of the core roller and the drive roller respectively, and ensure that the ratio of the linear speed of the drive roller to that of the core roller is greater than 1;

[0010] Step S5: Perform deformation heat treatment on the aluminum alloy ring or cylinder.

[0011] In step S1, the furnace temperature is 350-500℃.

[0012] In step S2, induction heating or infrared heating is used to continuously replenish the temperature on the outside of the ring or cylinder, while air cooling, mist cooling or air cooling is used to cool the inside of the ring or cylinder. The temperature difference between the inside and outside of the ring or cylinder is maintained between 50-150℃, and the temperature on the outside of the ring or cylinder is higher than that on the inside.

[0013] In step S2, the aluminum alloy ring or cylinder is placed on the working platform of the ring rolling equipment, and the core roller is inserted along the axis of the ring or cylinder so that the outer side of the ring or cylinder is close to the outer side of the drive roller. The outer side heating device and the inner side cooling device of the ring or cylinder are started simultaneously.

[0014] In step S3, the preheating temperature of the drive roller is 50-200°C higher than the preheating temperature of the core roller.

[0015] In step S4, the linear speed of the drive roller is set to 500-750 mm / s, and the linear speed of the core roller is set to 350-550 mm / s.

[0016] In step S5, the specific steps of the deformation heat treatment are as follows:

[0017] Step S51: Perform solution treatment. The solution temperature and solution time are determined according to the aluminum alloy grade and specifications.

[0018] Step S52: Subsequently, the ring or cylinder is cold-deformed by radial bulging or axial compression deformation;

[0019] Step S53: Finally, perform aging treatment on the cold-deformed ring or cylinder.

[0020] In step S4, the temperature difference ΔT and linear velocity difference ΔV between the outer and inner sides of the ring or cylinder achieve synergistic superposition of shear strains, resulting in the total shear strain:

[0021] γ=kγ1+γ2 (1)

[0022] γ1 is the first type of shear strain, and the formula is:

[0023] γ1=ΔV / havg·t (2)

[0024] γ2 is the second type of shear strain, and the formula is:

[0025] γ2=Δα·ΔT·t·h avg / v avg (3)

[0026] Where, k is the influence coefficient of metal flow difference caused by temperature difference changing the material deformation resistance, ΔV is the difference in linear velocity between the outer and inner sides of the ring / cylinder, t is the rolling contact time, Δα is the difference in the thermal expansion coefficient of the material, ΔT is the temperature difference between the outer and inner sides of the ring / cylinder, and h avg v represents the average thickness of the ring before and after rolling. avg This represents the average speed.

[0027] In step S4, a pulsed magnetic field is simultaneously applied to the deforming ring or cylinder. The parameters of the pulsed magnetic field are: magnetic induction intensity of 8T-13T and pulse width of 500ms-800ms. The direction of the magnetic field is along the axial direction of the ring or cylinder.

[0028] The technical details not described in this solution can be implemented based on the conventional understanding and operation of those skilled in the art, with reference to the accompanying drawings. They will not be elaborated further here.

[0029] The positive effects of this invention are as follows:

[0030] (1) The present invention provides a method for manufacturing aluminum alloy rings or cylinders with superimposed shear strain, which can fully utilize shear strain during the ring rolling process to improve the microstructure and properties of aluminum alloy rings or cylinders, and increases the ability to control the microstructure and improve the mechanical properties of rings or cylinders.

[0031] (2) The present invention utilizes shear strain to cause plastic deformation of rings or cylinders, no longer relying solely on radial line strain, which can solve the problem that thick-walled rings or cylinders cannot be rolled through in the traditional ring rolling process.

[0032] In traditional ring rolling, simply increasing radial deformation can easily cause damage and cracking of the ring or cylinder. However, this invention can cause plastic deformation of the ring or cylinder without relying on radial deformation, which reduces the tendency of the ring or cylinder to be damaged and cracked and increases process stability.

[0033] (3) By coordinating the linear velocity difference between the drive roller and the core roller, as well as the temperature difference between the outer and inner sides of the ring or cylinder, the shear strain in the plastic deformation zone of the aluminum alloy ring or cylinder produces an unexpected synergistic superposition effect, rather than the superposition of shear strain under the action of a single linear velocity difference and temperature difference. This can effectively improve the microstructure and mechanical properties of the aluminum alloy ring or cylinder. The ring or cylinder manufacturing method of this patent can also be used for various metal materials such as magnesium and titanium. It has strong portability and wide applicability.

[0034] (4) This scheme achieves the synergistic superposition of shear strains, where the first type of shear strain originates from the metal flow difference γ1=ΔV / h caused by the difference in linear velocity. avg ·t(h avg Here, γ2 represents the average thickness of the ring or cylinder before and after ring rolling, t represents the rolling contact time, and k represents the influence coefficient of metal flow difference caused by the temperature difference changing the material's deformation resistance. The second type of shear strain originates from the effect of temperature difference on the coefficient of thermal expansion, γ2 = Δα·ΔT·t·h. avg / v avg (Δα is the difference in the thermal expansion coefficients of the materials, and t is the rolling contact time);

[0035] Based on the temperature difference (ΔT) and linear velocity difference (ΔV) between the outer and inner sides of the ring / cylinder, the shear strain can be superimposed synergistically, and the total shear strain γ=kγ1+γ2;

[0036] By combining the simulation model, coupling the linear velocity difference between the drive roller and the core roller, and the temperature difference between the outer and inner sides of the plastic deformation zone of the ring or cylinder, the variation law of the total shear strain of the ring or cylinder in the plastic deformation zone with the ring rolling process is obtained. Based on this, the linear velocity difference between the drive roller and the core roller or the temperature difference between the outer and inner sides of the ring or cylinder is adjusted so that the total shear strain in the plastic deformation zone of the ring or cylinder reaches the critical strain of roll penetration. Based on this, the ring or cylinder is ring rolled to obtain aluminum alloy rings or cylinders.

[0037] (5) Specifically, the temperature difference between the outer and inner sides of the plastic deformation zone of the ring or cylinder will change the deformation resistance of the materials on the inner and outer sides of the ring or cylinder. The deformation resistance of the material on the high temperature side is small and the metal fluidity is strong, while the deformation resistance of the material on the low temperature side is large and the metal fluidity is poor. The difference in metal flow between the inner and outer sides of the ring or cylinder will increase the shear strain dominated by the difference in linear velocity. At the same time, the temperature difference causes the difference in the thermal expansion coefficient of the materials on the inner and outer sides of the ring or cylinder, which further contributes to the shear strain. By combining the effects of the temperature difference on the deformation resistance and the difference in thermal expansion coefficient of the material, the synergistic superposition of the shear strain in the plastic deformation zone of the ring or cylinder can be achieved.

[0038] (6) The effect of this scheme coupled pulsed magnetic field is that the pulsed magnetic field improves the processing performance of aluminum alloy, can break the coarse grains in the ring rolling deformation state, press the microcracks together, reduce or eliminate deformation defects. Due to the continuous rotation of the slip surface, defects such as vacancies, dislocations, grain boundaries, and heterogeneous phase particles are easily changed, which improves the processing performance of aluminum alloy and reduces the power consumption of ring rolling. Attached Figure Description

[0039] Figure 1 This is a schematic flowchart of the aluminum alloy ring or cylinder ring rolling manufacturing method in Embodiments 1 and 2 of this scheme.

[0040] Figure 2 This is a grain structure diagram of the 7050 aluminum alloy cylindrical component under conventional ring rolling in Example 1.

[0041] Figure 2-1 This is a grain structure diagram of the 7050 aluminum alloy cylindrical component under the ring rolling process in Example 1 of this scheme.

[0042] Figure 3 This is a diagram of the second phase microstructure of a 7050 aluminum alloy cylindrical component under conventional ring rolling in Example 1.

[0043] Figure 3-1 This is a diagram of the second phase microstructure of a 7050 aluminum alloy cylindrical component under the ring rolling process in Example 1 of this scheme.

[0044] Figure 4 This is a sampling diagram of the mechanical properties of the 7050 aluminum alloy cylinder in the aged state in Example 1 of this scheme.

[0045] Figure 5 This is a grain structure diagram of the 7085 aluminum alloy cylindrical component under conventional ring rolling in Example 2.

[0046] Figure 5-1 This is a grain structure diagram of the 7085 aluminum alloy cylindrical component under the ring rolling process in Example 2 of this scheme.

[0047] Figure 6 This is a diagram of the second phase microstructure of a 7085 aluminum alloy cylindrical component under conventional ring rolling in Example 2.

[0048] Figure 6-1 This is a diagram of the second phase microstructure of the 7085 aluminum alloy cylindrical component under the ring rolling process in Example 2 of this scheme.

[0049] Figure 7 This is a sampling diagram of the mechanical properties of the 7085 aluminum alloy cylinder in the aged state in Example 2 of this scheme.

[0050] Figure 8 This is a grain structure diagram of the 7085 aluminum alloy cylindrical component under the ring rolling process in Example 3 of this scheme.

[0051] Figure 9This is a schematic diagram showing the positions of the aluminum alloy ring or cylinder and the energized coil in Embodiment 3 of this scheme. Attached Figure Description

[0053] The attached diagram is labeled as follows: 1. Energized coil. Detailed Implementation

[0054] To more clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0055] Example 1

[0056] According to the manufacturing process proposed in this plan Figure 1 This is a schematic flowchart of the aluminum alloy ring or cylinder ring rolling manufacturing method in Embodiment 1 of this scheme, and the following 7050 aluminum alloy cylinder ring rolling process scheme is provided:

[0057] (1) Preheat the 7050 aluminum alloy cylinder at a temperature of 430±10℃ for 2 hours. The outer diameter of the cylinder is 800mm, the inner diameter is 500mm, and the height is 800mm.

[0058] (2) Take out the 7050 aluminum alloy cylinder from the heating furnace, use an induction heating fixture to supplement the temperature on the outside of the cylinder, and use an air cooling fixture to cool the temperature on the inside of the cylinder. At the same time, monitor the instantaneous temperature on the outside and inside of the cylinder. By continuously adjusting the power of the induction heating fixture and the air cooling fixture, ensure that the temperature difference between the outside and inside of the cylinder is maintained at about 100℃, where the temperature on the outside of the cylinder is higher than that on the inside, and the temperature on the outside is not lower than 400℃.

[0059] (3) Based on the temperature of the outer and inner sides of the cylinder, preheat the drive roller and the core roller, wherein the preheating temperature of the drive roller is 250±10℃ and the preheating temperature of the core roller is 150±10℃.

[0060] (4) Place the 7050 aluminum alloy cylinder on the working platform of the ring rolling equipment and insert the core roller along the cylinder axis; move the core roller and the cylinder so that the outer side of the cylinder is close to the outer side of the drive roller; monitor the temperature of the outer and inner sides of the cylinder in real time. If the temperature of the outer side of the cylinder is lower than 400℃, increase the power of the heating fixture on the outer side of the cylinder. If the temperature of the inner side of the cylinder is lower than 300℃, reduce the power of the air cooling fixture on the inner side of the cylinder to ensure that the temperature difference between the outer and inner sides of the cylinder is maintained at about 100℃.

[0061] (5) Set the core roller linear speed to 520 mm / s, the drive roller linear speed to 572 mm / s, and the ratio of the drive roller linear speed to the core roller linear speed to 1.1; to ensure stable forming, set the core roller feed speed to 1.25 mm / s and the rolling time to 40 s. This feed speed is also the relative motion speed between the drive roller and the core roller.

[0062] (6) Based on the above process parameter settings and the total shear strain calculation formula, the total shear strain is 0.52417, of which the first type of shear strain is 0.4368 with an influence coefficient of 1.2, and the second type of shear strain is 0.0000144. Combined with the simulation model, the above process parameters can penetrate the cylinder, and the cylinder can achieve uniform deformation. Based on this, the 7050 aluminum alloy cylinder ring rolling was completed, with an outer diameter of 1000mm, an inner diameter of 800mm, and a height of 866mm.

[0063] For example, based on the above process parameter settings, the average thickness of the cylinder before and after rolling is h. avg = [(1000-800) / 2+(800-500) / 2] / 2=125mm; Linear velocity difference Δv=572-520=52mm / s, Temperature difference ΔT=400-300=100℃, Thermal expansion coefficient difference Δα=0.6×10 -6 K -1 Average speed v avg = (572+520) / 2 = 546 mm / s, the rolling contact time t is obtained from simulation, the total rolling contact time is about 1.05 s, therefore the first type of shear strain γ1 = ΔV / h avg ·t=52 / 125·1.05=0.4368, the influence coefficient is 1.2, and the second type of shear strain is γ2=Δα·ΔT·t·h avg / v avg =0.6×10 -6 ·100·1.05·125 / 546=1.44×10 -5 The total shear strain is γ=kγ1+γ2=1.2·0.4368+1.44×10 -5 =0.52417.

[0064] Based on the temperature difference (ΔT) and linear velocity difference (ΔV) between the outer and inner sides of the ring or cylinder, the shear strain can be superimposed synergistically, resulting in a total shear strain γ = kγ1 + γ2, where γ1 = ΔV / h avg ·t represents the first type of shear strain, originating from the difference in metal flow caused by the difference in linear velocity (h) avg The average thickness of the ring or cylinder before and after ring rolling, t is the rolling contact time, k is the influence coefficient of metal flow difference caused by temperature difference changing the material deformation resistance, and γ2=Δα·ΔT·t·h avg / v avg This is the second type of shear strain, which originates from the effect of temperature difference on the coefficient of thermal expansion (Δα is the difference in the coefficient of thermal expansion of the materials, and t is the rolling contact time).

[0065] By combining simulation models and coupling the linear velocity difference between the drive roll and the core roll, as well as the temperature difference between the outer and inner sides of the plastic deformation zone of the ring or cylinder, the variation law of the total shear strain of the ring or cylinder in the plastic deformation zone with the ring rolling process is obtained. Based on this, the linear velocity difference between the drive roll and the core roll, or the temperature difference between the outer and inner sides of the ring or cylinder, is adjusted so that the total shear strain in the plastic deformation zone of the ring or cylinder reaches the critical strain of roll penetration. Based on this, the ring or cylinder is ring rolled to obtain aluminum alloy rings or cylinders.

[0066] (7) Perform deformation heat treatment on 7050 aluminum alloy cylindrical parts.

[0067] First, the cylindrical parts were subjected to graded solution treatment, with the solution temperature at 465℃ for 230 min, the solution temperature at 475℃ for 90 min, and the solution temperature at 480℃ for 80 min.

[0068] The cylinder was then subjected to water quenching and left to stand in water for 20 minutes.

[0069] Further, an expansion forming machine was used to perform cold expansion deformation of the cylindrical part, and the outer diameter of the cylindrical part was changed to 1020mm;

[0070] Finally, the cylinder is subjected to a three-stage aging treatment: aging temperature of 100℃ for 9 hours, aging temperature of 140℃ for 6 hours, and aging temperature of 100℃ for 21 hours. After aging, it is air-cooled.

[0071] Figure 2 and Figure 2-1 The images show a comparison of the grain structure of 7050 aluminum alloy cylindrical parts produced by conventional ring rolling and by the ring rolling process of this invention. The outer side of the ring-rolled cylindrical part of this invention has a temperature approximately 104°C higher than the inner side (outer side temperature approximately 401°C, inner side temperature approximately 297°C), while the outer and inner temperatures of the conventionally ring-rolled cylindrical part are approximately the same (outer side temperature approximately 392°C, inner side temperature approximately 385°C). Figure 2 and Figure 2-1 It can be observed that the 7050 aluminum alloy cylindrical parts produced by the ring rolling of this invention have a finer and more uniform grain structure, with an average grain size of approximately 280 μm, while the 7050 aluminum alloy cylindrical parts produced by conventional ring rolling have an elliptical grain morphology and a coarser grain size, with an average grain size of approximately 510 μm. Therefore, the ring rolling process of this invention is more conducive to manufacturing 7050 aluminum alloy cylindrical parts with finer grains.

[0072] Figure 3 and Figure 3-1 These are comparative diagrams of the second-phase microstructure of 7050 aluminum alloy cylindrical parts produced by conventional ring rolling and by the ring rolling method of this invention. Figure 3 and Figure 3-1As can be seen, the second phase of the conventionally ring-rolled 7050 aluminum alloy cylindrical component is distributed along the tangential direction of the component in a fibrous strip-like pattern, with the size of the fibrous strips reaching 130-360 μm. In contrast, the second phase of the 7050 aluminum alloy cylindrical component of this invention is diffusely distributed in the matrix, and although distributed along the tangential direction, it exhibits a discontinuous characteristic, with a maximum size of less than 110 μm. Therefore, the ring rolling of this invention is beneficial for fragmenting the second phase of the 7050 aluminum alloy cylindrical component. The conventional ring rolling refers to the deformation behavior under the condition of only radial deformation; the parameter settings can be referred to in Example 1 of this invention.

[0073] As can be seen from the above results, the 7050 aluminum alloy cylindrical parts prepared by this invention have a more uniform and finer grain structure, and the second phase size is also smaller. Sampling images of the inner surface and core of the 7050 aluminum alloy cylindrical parts produced by conventional ring rolling and ring rolling according to this invention are shown (see...). Figure 4 It was found that the strength and elongation of the 7050 aluminum alloy cylindrical parts rolled by the present invention are higher than those of the conventionally rolled 7050 aluminum alloy cylindrical parts. Table 1 shows the mechanical properties of the inner surface and core of the 7050 aluminum alloy cylindrical parts rolled by conventional rolling and by the 7050 aluminum alloy cylindrical parts rolled by the present invention in Example 1.

[0074]

[0075] As can be seen from Table 1, at positions 1 and 2, regardless of whether it is axial, radial, or tangential, after testing the tensile strength, specified non-proportional elongation strength Rp0.2, and end face reduction rate, the ring rolling process in this embodiment 1 achieved better technical results than the traditional process, with higher mechanical property data. This also shows that this embodiment 1 is effective in actual production.

[0076] Example 2

[0077] According to the manufacturing process proposed in this plan Figure 1 This is a flowchart illustrating the aluminum alloy ring or cylindrical component ring rolling manufacturing method in Embodiment 1 of this scheme, providing a ring rolling process scheme for 7085 aluminum alloy rings:

[0078] (1) Set the temperature of the heating furnace to 400±10℃ and keep it warm for 3-5 hours to preheat the 7085 aluminum alloy ring, wherein the outer diameter of the ring is 1700mm, the inner diameter is 650mm and the height is 300mm.

[0079] (2) Take the 7085 aluminum alloy ring out of the heating furnace, use an induction heating fixture to heat the outer surface of the ring, and use an air cooling fixture to cool the inner side of the ring. Monitor the instantaneous temperature of the outer and inner sides of the ring in real time. Based on this, continuously adjust the power of the induction heating fixture and the air cooling fixture to ensure that the temperature difference between the outer and inner sides of the ring is maintained at about 100℃, with the outer side temperature being higher than the inner side and the outer side temperature not lower than 400℃.

[0080] (3) Based on the temperatures of the outer and inner sides of the ring, preheat the drive roller and the core roller, wherein the preheating temperature of the drive roller is 200±10℃ and the preheating temperature of the core roller is 100±10℃.

[0081] (4) Place the 7085 aluminum alloy ring on the working platform of the ring rolling equipment and insert the mandrel along the ring axis; move the mandrel and the ring so that the outer side of the ring is close to the outer side of the drive roller; monitor the temperature of the outer and inner sides of the ring in real time. If the outer temperature is lower than 400°C, increase the power of the heating fixture on the outer side of the ring. If the inner temperature is lower than 300°C, reduce the power of the air cooling fixture on the inner side so that the temperature difference between the outer and inner sides of the ring is maintained at about 100°C.

[0082] (5) Set the core roller linear speed to 400 mm / s, the drive roller linear speed to 500 mm / s, and the ratio of the drive roller linear speed to the core roller linear speed to 1.25; to ensure stable forming, set the core roller feed speed to 5 mm / s and the rolling time to 55 s. Here, the core roller feed speed is also the relative motion speed between the drive roller and the core roller.

[0083] (6) Based on the above process parameter settings and the total shear strain calculation formula, the total shear strain is 0.476408, of which the first type of shear strain is 0.433 with an influence coefficient of 1.1, and the second type of shear strain is 0.000108. Simulation results show that the ring deforms uniformly under these process parameters. Based on this, the 7085 aluminum alloy ring was rolled and formed, with an outer diameter of 2200 mm, an inner diameter of 1700 mm, and a height of 379 mm.

[0084] For example, based on the above process parameter settings, the average thickness of the ring before and after rolling is h. avg = [(2200-1700) / 2+(1700-650) / 2] / 2=387.5mm; Linear velocity difference Δv=500-400=100mm / s, Temperature difference ΔT=400-300=100℃, Coefficient of thermal expansion Δα=0.6×10 -6 K -1 Average speed v avg = (500+400) / 2 = 450mm / s, the rolling contact time t is obtained from simulation, the total contact time is about 1.68s, therefore the first type of shear strain γ1 = ΔV / havg ·t=100 / 387.5·1.68=0.433, influence coefficient is 1.1, second-order shear strain γ2=Δα·ΔT·t·h avg / v avg =0.6×10 -6 ·100·2.09·387.5 / 450=1.08×10 -4 The total shear strain is γ=kγ1+γ2=1.1·0.433+1.08×10 -4 =0.476408.

[0085] The formulas used in the above calculations are all based on the situation in Example 1, which is hereby explained.

[0086] In Examples 1 and 2 above, the coupling of temperature difference (ΔT) and linear velocity difference (ΔV) is represented by an influence coefficient k. The superposition of shear strain originates from two aspects: one is the metal flow difference caused by the linear velocity difference, and the other is caused by the temperature difference (this factor is also divided into two parts: the influence of the difference in deformation resistance on the metal flow difference and the difference in thermal expansion coefficient). The influence of temperature difference on metal flow difference is reflected in the value of k.

[0087] (7) Perform deformation heat treatment on 7085 aluminum alloy rings. First, perform solution treatment. Set the solution furnace temperature to 450℃, load the rings into the furnace at the set temperature, and hold for 290 minutes. Then, raise the furnace temperature to 470℃, hold for 170 minutes, and then immerse the rings in water for solution treatment. The quenching transfer time should be less than or equal to 15 seconds, and the forgings should be immersed in water for at least 25 minutes.

[0088] Then, cold expansion forming is performed: the ring is cold expanded using an expansion forming machine, and the outer diameter of the ring after cold expansion forming is 2310mm.

[0089] Finally, the cold-expansion formed ring is subjected to a three-stage aging treatment. The furnace temperature is set to 120℃, the ring is loaded into the furnace at the set temperature and held for 20 hours. Then, the temperature is raised to 180℃ and held for 1.5 hours. The temperature is then lowered to 120℃ and held for 15 hours. Finally, the ring is removed and placed in the air to cool.

[0090] Figure 5 and Figure 5-1 The images show a comparison of the grain structure of 7085 aluminum alloy rings produced by conventional ring rolling and by the ring rolling method of this invention. The outer side of the ring rolled by this invention has a temperature approximately 110°C higher than the inner side (outer side temperature approximately 403°C, inner side temperature approximately 293°C), while the outer and inner sides of the ring rolled by conventional rolling are approximately the same (outer side temperature approximately 396°C, inner side temperature approximately 390°C). Figure 5 and Figure 5-1It can be observed that the grain structure of the 7085 aluminum alloy ring produced by the present invention is finer and more uniform compared to that of rings produced by conventional ring rolling. The average grain size of the ring produced by the present invention is approximately 440 μm, while the average grain size of the ring produced by conventional ring rolling is approximately 620 μm. The present invention is more conducive to the preparation of 7085 aluminum alloy rings with fine and uniform grain structure.

[0091] Figure 6 and Figure 6-1 These are comparative images of the second-phase microstructure of 7085 aluminum alloy rings produced by conventional ring rolling and by the ring rolling method of this invention. Figure 6 and Figure 6-1 As can be seen, the second phase of the conventionally rolled 7085 aluminum alloy ring is distributed tangentially in a fibrous strip pattern, with the size of the fibrous strip reaching 210-540 μm. In contrast, although the second phase of the 7085 aluminum alloy ring of this invention is distributed tangentially, it exhibits a discontinuous characteristic, with a maximum size of less than 100 μm. The conventional ring rolling process represents the deformation behavior under the condition of only radial deformation; the parameter settings can be referred to in Example 2.

[0092] As can be seen from the above results, the 7085 aluminum alloy ring prepared by this invention has a more uniform and finer grain structure and a more dispersed second phase distribution. Figure 7 Sampling images were taken to test the mechanical properties of the inner surface and core of the 7085 aluminum alloy rings produced by conventional ring rolling and the ring rolling of this invention. It was found that the 7085 aluminum alloy rings produced by the ring rolling of this invention have higher strength and elongation than the conventionally rolled 7085 aluminum alloy rings. Table 2 shows the mechanical property test results of the inner surface and core of the 7085 aluminum alloy cylindrical parts produced by conventional ring rolling and the ring rolling of 7085 aluminum alloy in Example 1 of this invention.

[0093]

[0094] As can be seen from Table 2, at positions 1 and 2, regardless of whether it is axial, radial, or tangential, after testing the tensile strength, specified non-proportional elongation strength Rp0.2, and end face shrinkage rate, the ring rolling process in this embodiment 2 achieved better technical results than the traditional process, with higher mechanical property data. This also shows that this embodiment 2 is effective in actual production.

[0095] Example 3

[0096] See Figure 9 Based on Example 2, Example 3 is introduced. Except for the following parameters of the pulsed magnetic field, all other parameters in Example 3 are the same as those in Example 2.

[0097] In step S4, a pulsed magnetic field is simultaneously applied to the deforming ring or cylinder. The parameters of the pulsed magnetic field are: magnetic induction intensity of 8T and pulse width of 500ms. The direction of the magnetic field is along the axial direction of the ring or cylinder. Figure 9 The energized coil 1 is located at the center of the ring or cylinder, and its specific position can be adjusted according to the structural adaptability of the ring or cylinder.

[0098] In this embodiment 3, the parameters of the pulsed magnetic field are calculated according to the minimum value of the range.

[0099] Figure 8 This is a grain structure diagram of the 7085 aluminum alloy cylindrical component under the ring rolling process in Example 3 of this scheme. From... Figure 8 As can be seen from the experiments, after pulsed magnetic field treatment and combined with shear deformation, the grain structure of the 7085 aluminum alloy ring produced by this invention is finer and more uniform than that of the ring in Example 2. The average grain size of the ring in Example 3 is approximately 260-380 μm, significantly reduced compared to 440 μm in Example 2. This invention is more conducive to preparing 7085 aluminum alloy rings with fine and uniform grain structure, demonstrating that coupled pulsed magnetic field and shear deformation (radial and tangential deformation) have a positive effect on reducing the average grain size. To simplify the experimental study, the effect of different pulsed magnetic field parameter variations on the grain structure of the 7085 aluminum alloy ring was not tested in Example 3, but existing experiments can demonstrate that the coupling of the pulsed magnetic field helps to reduce the average grain size, which will not be elaborated here.

[0100] It should be noted that in Examples 1-3, the mechanical properties were not further tested, but considering the effect of refining the grains, it can be indirectly concluded that the mechanical properties of the aluminum alloy parts are also improved.

[0101] The technical features of this invention not described can be implemented by or using existing technology, and will not be repeated here. Of course, the above description is not a limitation of this invention, and this invention is not limited to the examples above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention should also be within the protection scope of this invention.

Claims

1. A ring rolling manufacturing process for aluminum alloy rings or cylinders based on shear strain superposition, characterized in that, Specifically, the steps include the following: Step S1: Preheat the aluminum alloy ring or cylinder in a heating furnace; Step S2: Remove the aluminum alloy ring or cylinder from the heating furnace, heat the outer side of the aluminum alloy ring or cylinder, and cool the inner side to create a temperature difference between the outer and inner sides of the ring or cylinder. Step S3: Based on the temperatures of the outer and inner sides of the ring or cylinder, preheat the drive roller and core roller simultaneously, with the drive roller and core roller respectively in contact with the outer and inner sides of the ring or cylinder. Step S4: Set the linear speeds of the core roll and drive roll respectively, and start the ring rolling deformation process; Step S5: Perform deformation heat treatment on the aluminum alloy ring or cylinder.

2. The ring rolling manufacturing process for aluminum alloy rings or cylinders based on shear strain superposition according to claim 1, characterized in that, In step S1, the furnace temperature is 350-500℃.

3. The ring rolling manufacturing process for aluminum alloy rings or cylinders based on shear strain superposition according to claim 1, characterized in that, In step S2, induction heating or infrared heating is used to continuously replenish the temperature on the outside of the ring or cylinder, while air cooling, mist cooling or air cooling is used to cool the inside of the ring or cylinder. The temperature difference between the inside and outside of the ring or cylinder is maintained between 50-150℃, and the temperature on the outside of the ring or cylinder is higher than that on the inside.

4. The ring rolling manufacturing process for aluminum alloy rings or cylinders based on shear strain superposition according to claim 3, characterized in that, In step S2, the aluminum alloy ring or cylinder is placed on the working platform of the ring rolling equipment, and the core roller is inserted along the axis of the ring or cylinder so that the outer side of the ring or cylinder is close to the outer side of the drive roller. The outer side heating device and the inner side cooling device of the ring or cylinder are started simultaneously.

5. The ring rolling manufacturing process for aluminum alloy rings or cylinders based on shear strain superposition according to claim 1, characterized in that, In step S3, the preheating temperature of the drive roller is 50-200°C higher than the preheating temperature of the core roller.

6. The ring rolling manufacturing process for aluminum alloy rings or cylinders based on shear strain superposition according to claim 1, characterized in that, In step S4, the linear speed of the drive roller is set to 500-750 mm / s, the linear speed of the core roller is set to 350-550 mm / s, and the ratio of the linear speeds of the drive roller and the core roller is greater than 1.

7. The ring rolling manufacturing process for aluminum alloy rings or cylinders based on shear strain superposition according to claim 3, characterized in that, In step S5, the specific steps of the deformation heat treatment are as follows: Step S51: Perform solution treatment. The solution temperature and solution time are determined according to the aluminum alloy grade and specifications. Step S52: Subsequently, the ring or cylinder is cold-deformed by radial bulging or axial compression deformation; Step S53: Finally, perform aging treatment on the cold-deformed ring or cylinder.

8. The ring rolling manufacturing process for aluminum alloy rings or cylinders based on shear strain superposition according to claim 1, characterized in that, In step S4, the temperature difference ΔT and linear velocity difference ΔV between the outer and inner sides of the ring or cylinder achieve synergistic superposition of shear strains, resulting in the total shear strain: γ=kγ1+γ2 (1) γ1 is the first type of shear strain, and the formula is: γ1=ΔV / h avg ·t (2) γ2 is the second type of shear strain, and the formula is: γ2=Δα·ΔT·t·h avg / v avg (3) Where, k is the influence coefficient of metal flow difference caused by temperature difference changing the material deformation resistance, ΔV is the difference in linear velocity between the outer and inner sides of the ring or cylinder, t is the rolling contact time, Δα is the difference in the thermal expansion coefficient of the material, ΔT is the temperature difference between the outer and inner sides of the ring or cylinder, and h avg v represents the average thickness of the ring before and after rolling. avg This represents the average speed.

9. The ring rolling manufacturing process for aluminum alloy rings or cylinders based on shear strain superposition according to claim 1, characterized in that, In step S4, a pulsed magnetic field is simultaneously applied to the deformed ring or cylinder. The parameters of the pulsed magnetic field are: magnetic induction intensity of 8T-13T, pulse width of 500ms-800ms, and magnetic field direction along the axial direction of the ring or cylinder.

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