Temperature-controlled rolling forming method for large-thickness high-performance steel / aluminum alloy composite plate

Abstract

The present application belongs to the technical field of metal layered composite material preparation, and particularly relates to a temperature control rolling forming method for a large-thickness high-performance steel / aluminum alloy composite plate, which comprises the following steps: assembling thin aluminum alloy plates and thick steel plates, rolling the plates after heating and holding to obtain a steel / thin aluminum alloy pre-composite plate, and roughening the aluminum alloy surface of the plate; heating the steel / thin aluminum alloy pre-composite plate and thick aluminum alloy plates to a solid solution temperature respectively and holding, assembling the plates to obtain a pre-composite plate / aluminum alloy plate assembly, and then performing holding treatment; feeding the pre-composite plate / aluminum alloy plate assembly into an isothermal rolling mill for rolling, with an isothermal rolling reduction of 30%-40% and a temperature of 460-500 DEG C; quenching the steel surface and the aluminum alloy surface of the large-thickness steel / aluminum alloy composite plate respectively, and then performing aging treatment to obtain a large-thickness high-performance steel / aluminum alloy composite plate; the rolling and solid solution are simultaneously completed through isothermal rolling, and the problems of warping of the large-thickness composite plate and difficulty in coordinating high-strength bonding at the interface and matrix strengthening are solved.

Description

Technical Field

[0001] This invention belongs to the field of metal layered composite material preparation technology, and particularly relates to a method for temperature-controlled rolling forming of thick, high-performance steel / aluminum alloy composite plates. Background Technology

[0002] With the rapid development of aerospace, new energy vehicles, and high-end equipment, the demand for structural materials that combine lightweight and high strength is becoming increasingly urgent. Steel / aluminum alloy composite plates, using heat-treatable aluminum alloys and steel as the base material, can comprehensively leverage the high strength and stiffness of steel with the lightweight, excellent electrical and thermal conductivity, and corrosion resistance of aluminum alloys, making them an ideal material choice for achieving lightweight and multifunctional designs. Currently, the main methods for preparing thick steel / aluminum composite plates include explosive bonding and rolling bonding. While explosive bonding can produce relatively thick composite plates, when the aluminum layer uses heat-treatable aluminum alloys, the explosive impact can easily lead to uncontrolled brittle compound layer formation at the interface and overheating of the aluminum matrix, preventing effective bonding. Rolling bonding has gradually become mainstream due to its stable product performance and suitability for large-scale production. However, limited by the significant differences in the thermophysical properties of steel and aluminum alloys, existing rolling bonding methods can only produce composite plates with a thickness of 5mm or less. For thick composite plates exceeding 20mm, the large reduction rate required for effective interface bonding during rolling can easily cause incoordination in the deformation of steel and aluminum, leading to severe warping of the composite plate.

[0003] Furthermore, heat-treatable aluminum alloys require solution treatment and aging treatment to achieve high-strength matrix properties. However, the solution treatment temperature range of aluminum alloys coincides with the rapid growth temperature range of intermetallic compounds at the steel / aluminum interface. In traditional processes, if the composite plate is rolled into shape first and then subjected to solution treatment separately, the interface will remain at high temperature for a long time, resulting in the formation of an excessively thick brittle compound layer, which severely reduces the bonding strength. If solution treatment is omitted, the aluminum alloy matrix cannot be strengthened, and the overall mechanical properties of the composite plate are greatly reduced. Summary of the Invention

[0004] The purpose of this invention is to provide a method for temperature-controlled rolling of thick, high-performance steel / aluminum alloy composite plates to solve the above-mentioned problems.

[0005] To achieve the above objectives, the present invention provides the following solution: The method for temperature-controlled rolling forming of thick, high-performance steel / aluminum alloy composite plates includes the following steps: Pre-composite: A steel / thin aluminum alloy billet is obtained by assembling a thin aluminum alloy plate and a thick steel plate. The steel / thin aluminum alloy billet is heated and held at a certain temperature, then rolled to obtain a steel / thin aluminum alloy pre-composite plate. The aluminum alloy surface of the steel / thin aluminum alloy pre-composite plate is roughened by grinding. Secondary billet assembly: The steel / thin aluminum alloy pre-composite plate and the thick aluminum alloy plate are heated to the solution temperature and held at the temperature. The steel / thin aluminum alloy pre-composite plate and the thick aluminum alloy plate are assembled to obtain a pre-composite plate / aluminum alloy plate billet, which is then held at the temperature. Isothermal rolling: The pre-composite plate / aluminum alloy plate billet is fed into an isothermal rolling mill for rolling to obtain a thick steel / aluminum alloy composite plate; Among them, the reduction rate of isothermal rolling is 30%-40%, and the temperature is 460-500℃; Post-processing: The steel and aluminum alloy surfaces of the thick steel / aluminum alloy composite plate are quenched separately and then aged to obtain a thick high-performance steel-aluminum alloy composite plate.

[0006] First, a pre-composite step is used to assemble a thin aluminum alloy sheet and a thick steel plate. After heating and holding at a certain temperature, a steel / thin aluminum alloy pre-composite plate is obtained by rolling. The steel / thin aluminum alloy pre-composite plate achieves preliminary mechanical bonding and local metallurgical bonding between the steel and aluminum, providing a stable intermediate transition layer for subsequent composite with the thick aluminum alloy sheet. Subsequently, the steel / thin aluminum alloy pre-composite plate and the thick aluminum alloy plate are heated to their solution temperature and held at that temperature to bring the aluminum alloy matrix to a solution state. After assembly, isothermal rolling is performed at a reduction rate of 30%-40% and a temperature of 460-500℃ to complete the final rolling. During this process, rolling deformation and solution treatment are carried out simultaneously, which achieves strong interfacial bonding and coordinated deformation of components while avoiding excessive growth of interfacial compounds. After rolling, the steel and aluminum alloy surfaces of the thick steel / aluminum alloy composite plate are quenched separately. Differential cooling based on the differences in the thermophysical properties of the two materials can be achieved, effectively suppressing warping and fixing the solution state. Finally, precipitation strengthening is completed by aging treatment, thus obtaining a thick, high-performance steel-aluminum alloy composite plate.

[0007] Preferably, before pre-composite bonding, it is necessary to remove oil and oxide film from the surfaces of the thin aluminum alloy plate, thick steel plate, and thick aluminum alloy plate to be bonded, and then roughen the bonding surfaces of the thin aluminum alloy plate, thick steel plate, and thick aluminum alloy plate.

[0008] Before pre-composite bonding, oil and oxide film on the surfaces of thin aluminum alloy plates, thick steel plates, and thick aluminum alloy plates are removed, and the surfaces to be bonded are roughened to ensure that the composite interface is clean and free of impurities. At the same time, the roughened surface can form a mechanical locking effect under rolling pressure, which enhances the interface bonding strength and creates conditions for subsequent metallurgical bonding.

[0009] Preferably, the initial thickness ratio of the thick steel plate to the thin aluminum alloy plate is 5:1-20:1, and the initial thickness ratio of the thick aluminum alloy plate to the thick steel plate is 2:1-1:1.

[0010] The initial thickness ratio of thick steel plate to thin aluminum alloy plate is limited to 5:1-20:1, and the initial thickness ratio of thick aluminum alloy plate to thick steel plate is 2:1-1:1. This ensures that the deformation of the steel layer and aluminum layer can be coordinated during the pre-composite and isothermal rolling processes, avoiding warping or interface cracking due to excessive thickness difference. At the same time, it enables the total thickness of the final composite plate to reach more than 20mm, achieving effective preparation of large thickness specifications.

[0011] Preferably, the roughness of the rough surface of the thin aluminum alloy plate and the thick aluminum alloy plate is 4μm≤Ra≤100μm, and the roughness of the rough surface of the thick steel plate is 15μm≤Ra≤250μm.

[0012] The surface roughness of thin and thick aluminum alloy plates is limited to 4μm≤Ra≤100μm, while the surface roughness of thick steel plates is limited to 15μm≤Ra≤250μm. Appropriately increasing the roughness of the steel side facilitates the formation of stronger mechanical anchoring points during pre-composite rolling, while the relatively lower roughness of the aluminum alloy side avoids excessive stress concentration. The combination of these two factors optimizes the interfacial bonding quality.

[0013] Preferably, during the pre-composite process, the heating temperature of the steel / thin aluminum alloy billet is 200-250℃, the holding time is 1-2h, and the rolling reduction rate is 15%-30%.

[0014] In the pre-composite process, the steel / thin aluminum alloy billet is heated to 200-250℃ and held for 1-2 hours, followed by rolling at a reduction rate of 15%-30%. The low-temperature heating conditions prevent solution treatment or over-aging of the heat-treatable aluminum alloy; while the 15%-30% reduction rate further extrudes residual air between the interfaces through intense plastic deformation and presses the edges of the sheet together to block the intrusion of external oxygen sources, thus achieving effective oxidation prevention in the interface area. Under this synergistic effect, the fresh surfaces of the steel and aluminum achieve sufficient mechanical interlocking and local metallurgical bonding, ultimately forming a stable pre-composite plate with a clean interface and no brittle oxide layer interference, providing a reliable intermediate transition layer for subsequent high-temperature isothermal rolling.

[0015] Preferably, after obtaining the steel / thin aluminum alloy pre-composite plate, the oil and oxide layer on the surface of the steel / thin aluminum alloy pre-composite plate are first removed, and then the aluminum alloy surface of the steel / thin aluminum alloy pre-composite plate is polished to a roughness of 4μm≤Ra≤100μm.

[0016] After pre-composite, the oil and oxide layer on the surface of the steel / thin aluminum alloy pre-composite plate are removed, and its aluminum alloy surface is polished to a roughness of 4μm≤Ra≤100μm. This removes the contaminants that may be generated during the pre-composite process. At the same time, the newly formed rough surface is conducive to the interface bonding with the thick aluminum alloy plate during the secondary assembly, ensuring the reliability of the secondary composite.

[0017] Preferably, during the secondary billet assembly process, the heat preservation time for the steel / thin aluminum alloy pre-composite plate is 20-40 min, the heat preservation time for the thick aluminum alloy plate is 60-180 min, and the heat preservation time for the pre-composite plate / aluminum alloy plate assembly is 10-20 min.

[0018] During the secondary billet assembly process, the steel / thin aluminum alloy pre-composite plate is held at temperature for 20-40 minutes, and the thick aluminum alloy plate is held at temperature for 60-180 minutes. After billet assembly, it is held at temperature for 10-20 minutes. The longer holding time for the thick aluminum alloy plate ensures that its internal temperature is fully homogenized, ensuring that the entire thick aluminum plate reaches the solution temperature. The relatively shorter holding time for the pre-composite plate reduces the growth of interfacial compounds. The short holding time after billet assembly makes the temperatures of both plates tend to be consistent, creating uniform temperature conditions for isothermal rolling.

[0019] Preferably, during the post-processing, the temperature of the quenching liquid is 20-40℃, the spraying pressure on the aluminum alloy side of the thick steel / aluminum alloy composite plate is 0.6-1.2MPa, and the spraying pressure on the steel side is 0.3-0.6MPa.

[0020] During post-processing, the quenching fluid temperature is 20-40℃, the spray pressure on the aluminum alloy side is 0.6-1.2MPa, and the spray pressure on the steel side is 0.3-0.6MPa. This differentiated spray pressure design takes into account the different specific heat capacities and thermal conductivity of steel and aluminum alloys. The aluminum alloy side requires a higher cooling rate to suppress the precipitation of the second phase and retain the solid solution state, while the steel side uses a lower pressure to avoid excessive thermal stress that could lead to warping or cracking. This achieves simultaneous quenching with good plate shape.

[0021] Preferably, during the aging process, the temperature inside the aging furnace is 160-180℃, and the holding time is 6-12h.

[0022] During the aging process, the temperature inside the aging furnace is 160-180℃, and the holding time is 6-12 hours. Targeting the precipitation strengthening characteristics of heat-treatable aluminum alloys, fine and uniform strengthening phases can be precipitated within this temperature and time range, which significantly improves the mechanical properties of the aluminum alloy matrix without affecting the bonding strength between the steel and aluminum interfaces, ultimately obtaining a thick, high-performance steel-aluminum alloy composite plate.

[0023] Compared with the prior art, the present invention has the following advantages and technical effects: This invention first obtains a steel / thin aluminum alloy pre-composite plate through a pre-composite step, providing a stable intermediate transition layer for subsequent composite with a thick aluminum alloy plate. This effectively alleviates the deformation incoordination problem caused by the difference in thermophysical properties between steel and aluminum alloy, and avoids the warping phenomenon in the traditional rolling process of thick composite plates. In the secondary billet assembly step, the steel / thin aluminum alloy pre-composite plate and the thick aluminum alloy plate are heated to their solution temperature and held at that temperature, allowing the aluminum alloy matrix to reach a solution-free state beforehand. Subsequently, during isothermal rolling, a reduction rate of 30%-40% and a roll temperature of 460-500℃ are used to ensure that rolling deformation and solution treatment are completed simultaneously, achieving rolling instead of solution treatment. This invention significantly shortens the residence time of the steel / aluminum interface in the high-temperature solution region and strictly limits the growth of intermetallic compounds at the interface to the level required for high-strength bonding, thereby resolving the contradiction between the solution treatment required for matrix strengthening and the excessively rapid growth of brittle phases at the interface. After rolling, the steel and aluminum alloy surfaces are quenched separately, allowing for differentiated cooling based on the differences in the thermophysical properties of the two materials. This not only fixes the solid solution state of the aluminum alloy but also controls the distribution of thermal stress, further ensuring the flatness of the composite plate. Finally, aging treatment causes fine and uniform strengthening phases to precipitate in the aluminum alloy matrix, significantly improving mechanical properties. This invention achieves high-strength bonding in thick, high-performance steel-aluminum alloy composite plates, synergistic control of component deformation and matrix strengthening, and simplifies the process flow while reducing energy consumption. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort: Figure 1 This is a schematic diagram of the process of the present invention; The components include: 1. Thin aluminum alloy sheet; 2. Thick steel plate; 3. Steel / thin aluminum alloy billet; 4. No. 1 heating furnace; 5. Two-roll flat rolling mill; 6. Steel / thin aluminum alloy pre-composite plate; 7. Thick aluminum alloy sheet; 8. No. 2 heating furnace; 9. No. 3 heating furnace; 10. Pre-composite plate / aluminum alloy sheet billet; 11. Holding furnace; 12. Induction heating device; 13. Isothermal rolling mill; 14. Aluminum alloy side spray device; 15. Thick steel / aluminum alloy composite plate; 16. Steel side spray device; 17. Coolant channel; 18. Aging furnace. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Reference Figure 1 This invention discloses a method for temperature-controlled rolling of thick, high-performance steel / aluminum alloy composite plates, the steps of which are as follows: Pre-composite: Thin aluminum alloy plate 1 and thick steel plate 2 are assembled to obtain steel / thin aluminum alloy billet 3. After heating and holding the steel / thin aluminum alloy billet 3, it is rolled to obtain steel / thin aluminum alloy pre-composite plate 6. The aluminum alloy surface of steel / thin aluminum alloy pre-composite plate 6 is roughened by grinding. Secondary billet assembly: The steel / thin aluminum alloy pre-composite plate 6 and the thick aluminum alloy plate 7 are heated to the solution temperature and held at the temperature. The steel / thin aluminum alloy pre-composite plate 6 and the thick aluminum alloy plate 7 are assembled to obtain the pre-composite plate / aluminum alloy plate assembly 10, followed by heat preservation treatment. Isothermal rolling: The pre-composite plate / aluminum alloy plate billet 10 is fed into the isothermal rolling mill 13 for rolling to obtain a thick steel / aluminum alloy composite plate 15. Among them, the reduction rate of isothermal rolling is 30%-40%, and the temperature is 460-500℃; Post-processing: The steel and aluminum alloy surfaces of the thick steel / aluminum alloy composite plate 15 are quenched and then aged to obtain a thick high-performance steel-aluminum alloy composite plate.

[0028] To further optimize the solution, before pre-composite bonding, it is necessary to remove oil and oxide film from the surfaces of the thin aluminum alloy plate 1, thick steel plate 2, and thick aluminum alloy plate 7 to be bonded, and then roughen the bonding surfaces of the thin aluminum alloy plate 1, thick steel plate 2, and thick aluminum alloy plate 7.

[0029] Further optimization of the scheme: the initial thickness ratio of thick steel plate 2 to thin aluminum alloy plate 1 is 5:1-20:1, and the initial thickness ratio of thick aluminum alloy plate 7 to thick steel plate 2 is 2:1-1:1.

[0030] Further optimization of the scheme: the roughness of the rough surface of the thin aluminum alloy plate 1 and the thick aluminum alloy plate 7 is 4μm≤Ra≤100μm, and the roughness of the rough surface of the thick steel plate 2 is 15μm≤Ra≤250μm.

[0031] Further optimization of the scheme: during the pre-composite process, the heating temperature of the steel / thin aluminum alloy billet 3 is 200-250℃, the holding time is 1-2h, and the rolling reduction rate is 15%-30%.

[0032] To further optimize the scheme, after obtaining the steel / thin aluminum alloy pre-composite plate 6 through pre-composite process, the oil and oxide layer on the surface of the steel / thin aluminum alloy pre-composite plate 6 are first removed, and then the aluminum alloy surface of the steel / thin aluminum alloy pre-composite plate 6 is polished to a roughness of 4μm≤Ra≤100μm.

[0033] Further optimization of the scheme: during the secondary billet assembly process, the heat preservation time of steel / thin aluminum alloy pre-composite plate 6 is 20-40 min, the heat preservation time of thick aluminum alloy plate 7 is 60-180 min, and the heat preservation time of pre-composite plate / aluminum alloy plate assembly 10 is 10-20 min.

[0034] Further optimization of the scheme: during the post-processing, the temperature of the quenching liquid is 20-40℃, the spraying pressure on the aluminum alloy side of the thick steel / aluminum alloy composite plate is 0.6-1.2MPa, and the spraying pressure on the steel side is 0.3-0.6MPa.

[0035] The scheme was further optimized so that the temperature inside the aging furnace 18 during the aging process was 160-180℃ and the holding time was 6-12h.

[0036] Detailed Process: First, prepare the blanks by taking the thin aluminum alloy plate 1, thick steel plate 2, and thick aluminum alloy plate 7 to be laminated, and removing oil and oxide film from their surfaces. Then, roughen the surfaces to be laminated on the thin aluminum alloy plate 1, thick steel plate 2, and thick aluminum alloy plate 7 by grinding. Specifically, the surface roughness Ra of the thin aluminum alloy plate 1 and thick aluminum alloy plate 7 is controlled to be 4μm to 100μm, and the surface roughness Ra of the thick steel plate 2 is controlled to be 15μm to 250μm. The initial thickness ratio of the thick steel plate 2 to the thin aluminum alloy plate 1 is set to 5:1 to 20:1, and the initial thickness ratio of the thick aluminum alloy plate 7 to the thick steel plate 2 is set to 2:1 to 1:1. The thick steel plate 2 to be laminated can be any of the following: steel for shipbuilding and marine engineering, stainless steel or alloy steel, with a thickness of 16 to 20 mm; the thin aluminum alloy plate 1 can be any of the following: 2-series, 6-series or 7-series aluminum alloy, with a thickness of 1 to 4 mm; the thick aluminum alloy plate 7 to be laminated can also be any of the following: 2-series, 6-series or 7-series aluminum alloy, with a thickness of 20 to 30 mm.

[0037] After billet preparation, the pre-composite step begins. The treated thin aluminum alloy sheet 1 and thick steel sheet 2 are assembled, with their rough surfaces in contact, to obtain a steel / thin aluminum alloy billet 3. This billet is then placed in a No. 1 heating furnace 4 and heated to 200-250°C, held for 1-2 hours, and subsequently rolled using a two-roll flat rolling mill 5 at a reduction rate of 15%-30% to produce a steel / thin aluminum alloy pre-composite plate 6. The interface of the steel-thin aluminum alloy pre-composite plate 6 achieves both mechanical interlocking and localized metallurgical bonding. After pre-composite preparation, oil and oxide layers are removed from the surface of the steel / thin aluminum alloy pre-composite plate 6, and its aluminum alloy surface is polished to a roughness Ra of 4μm-100μm, preparing it for subsequent secondary assembly.

[0038] Next, the secondary assembly step is performed. The steel / thin aluminum alloy pre-composite plate 6 and the thick aluminum alloy plate 7 are placed in heating furnace 9 (No. 3) and heating furnace 8 (No. 2) respectively and heated to their respective solution temperatures. For 2-series aluminum alloys, the solution temperature is 490 to 505℃; for 6-series aluminum alloys, the solution temperature is 520 to 550℃; and for 7-series aluminum alloys, the solution temperature is 465 to 500℃. The holding time for the steel / thin aluminum alloy pre-composite plate 6 is 20 to 40 minutes, and the holding time for the thick aluminum alloy plate 7 is 60 to 180 minutes, to ensure sufficient temperature uniformity within the thick aluminum alloy plate. After heating and holding, the steel / thin aluminum alloy pre-composite plate 6 and the thick aluminum alloy plate 7 are assembled, with their rough surfaces in contact, to obtain the pre-composite plate / aluminum alloy plate assembly 10. The pre-composite plate / aluminum alloy plate assembly 10 is then placed in a holding furnace and held for 10 to 20 minutes to ensure that the temperatures of both plates are consistent.

[0039] The isothermal rolling process then proceeds. The pre-composite plate / aluminum alloy plate billet 10, after heat preservation, is fed into the isothermal rolling mill 13 for rolling. The roll surface temperature of the isothermal rolling mill 13 is maintained at 460 to 500°C, and the rolling reduction rate is controlled at 30% to 40%. During the isothermal rolling process, a medium-high frequency induction heating device 12 is installed on the outer side of the non-working arc section of the roll. The induction heating device 12 covers approximately one-sixth of the circumference of the roll, providing local induction heating to the roll surface and ensuring that the roll surface temperature remains constant within the solution temperature range. Simultaneously, a coolant channel 17 is provided inside the roll neck. Cooling water is continuously circulated into the channel to cool the bearing area and prevent the bearing from overheating. Under these conditions, the pre-composite plate / aluminum alloy plate billet 10 undergoes a large reduction, the steel layer and the aluminum alloy layer achieve coordinated deformation, and the interface achieves strong bonding. At the same time, the aluminum alloy matrix undergoes solution treatment simultaneously during the rolling process, forming a solution-treated structure, resulting in a rolled thick steel / aluminum alloy composite plate 15.

[0040] Post-processing is performed immediately after rolling. First, quenching is conducted. An aluminum alloy-side spray device 14 and a steel-side spray device 16 are installed at the rolling exit to spray and quench the aluminum alloy and steel surfaces of the thick steel / aluminum alloy composite plate 15, respectively. The quenching liquid temperature is 20 to 40°C, the spray pressure on the aluminum alloy side is 0.6 to 1.2 MPa, and the spray pressure on the steel side is 0.3 to 0.6 MPa. This differentiated spray pressure design considers the different specific heat capacities and thermal conductivity of steel and aluminum alloy. The aluminum alloy side requires a higher cooling rate to suppress second-phase precipitation and retain the solid solution state, while the steel side uses a lower pressure to avoid excessive thermal stress leading to warping. After quenching, the composite plate is sent to an aging furnace 18 for artificial aging treatment. The furnace temperature is 160 to 180°C, and the holding time is 6 to 12 hours. Under these aging conditions, fine and uniform reinforcing phases precipitate in the aluminum alloy matrix, significantly improving mechanical properties without affecting the bonding strength of the steel / aluminum interface, ultimately resulting in a thick, high-performance steel-aluminum alloy composite plate.

[0041] The thick steel / aluminum alloy composite plates prepared by the above method can reach a total thickness of over 20 mm, exhibiting good interfacial bonding, a straight and warp-free plate shape, and sufficient precipitation strengthening of the aluminum alloy matrix, resulting in excellent overall performance. This invention integrates solution treatment and final rolling into the same isothermal rolling process, achieving "rolling instead of solution treatment." This significantly shortens the residence time of the interface in the high-temperature solution zone, resolving the contradiction between matrix strengthening and the excessively rapid growth of brittle phases at the interface. Simultaneously, it simplifies the process flow and reduces energy consumption.

[0042] Example 1 The thick steel plate 2 used is CCSB steel for shipbuilding and marine engineering, with a length × width × height of 200mm × 100mm × 16mm; the thin aluminum alloy plate 1 used is 6061 aluminum alloy, with a length × width × height of 200mm × 100mm × 2mm; the thick aluminum alloy plate 7 used is 6061 aluminum alloy, with a length × width × height of 200mm × 100mm × 20mm.

[0043] The forming method includes the following steps: S1. Blank Preparation: Remove oil and oxide film from the surface of thin aluminum alloy plate 1 and roughen one side to a roughness Ra=4μm; remove oil and oxide film from the surface of thick steel plate 2 and roughen one side to a roughness Ra=15μm; remove oil and oxide film from the surface of thick aluminum alloy plate 7 and roughen one side to a roughness Ra=4μm. The initial thickness ratio of thick steel plate 2 to thin aluminum alloy plate 1 is 16:1, and the initial thickness ratio of thick aluminum alloy plate 7 to thick steel plate 2 is 1.25:1.

[0044] S2. Low-temperature pre-composite: The thick steel plate 2 treated in S1 and the thin aluminum alloy plate 1 are combined to obtain a steel / thin aluminum alloy pre-composite 3 with the rough surfaces in contact. The pre-composite 3 is heated to 250°C using a No. 1 heating furnace 4 and held for 1 hour. It is rolled with a reduction rate of 20% and a two-roll flat rolling mill 5 is used to prepare a steel / thin aluminum alloy pre-composite plate 6 with interfacial mechanical interlocking and local metallurgical bonding.

[0045] S3. Surface treatment of pre-composite plate: Remove oil and oxide film from the surface of the steel / thin aluminum alloy pre-composite plate 6 obtained in step S2, and roughen the aluminum alloy surface to a roughness of Ra=4μm.

[0046] S4. Temperature Control Heating and Billet Assembly: The steel / thin aluminum alloy pre-composite plate 6 treated in S3 and the thick aluminum alloy plate 7 treated in S1 are placed in heating furnace No. 3 (9) and heating furnace No. 2 (8) respectively for heating. The steel / thin aluminum alloy pre-composite plate 6 is heated to the solution temperature of 520℃ and held for 20 minutes; the thick aluminum alloy plate 7 is heated to the solution temperature of 520℃ and held for 60 minutes; the heated steel / thin aluminum alloy pre-composite plate 6 and the thick aluminum alloy plate 7 are assembled to obtain a pre-composite plate / aluminum alloy plate billet 10, which is then held in holding furnace 11 for 10 minutes, so that the rough surfaces of the steel / thin aluminum alloy pre-composite plate 6 and the thick aluminum alloy plate 7 are in contact.

[0047] S5. Isothermal rolling: The pre-composite plate / aluminum alloy plate billet 10 after S4 heat preservation is fed into the isothermal rolling mill 13 and rolled with a reduction rate of 30% to prepare a rolled thick steel / aluminum alloy composite plate 15; wherein the roll surface temperature of the isothermal rolling mill 13 is 460℃.

[0048] S6. Quenching: At the rolling exit, the thick steel / aluminum alloy composite plate 15 rolled in S5 is quenched using the aluminum alloy side spray device 14 and the steel side spray device 16 respectively. The spray pressure on the aluminum alloy side is 0.6MPa, the spray pressure on the steel side is 0.3MPa, and the spray water temperature is 20℃.

[0049] S7. Aging treatment: The thick steel / aluminum alloy composite plate 15 after quenching is subjected to artificial aging treatment. The temperature of the aging furnace 18 is 160℃ and the holding time is 6 hours.

[0050] The final high-performance steel-aluminum alloy composite plate has a total thickness of approximately 22.3 mm, an interfacial shear strength of up to 140.5 MPa, an interfacial pull-out strength of approximately 200.3 MPa, good interfacial bonding, and no warping.

[0051] Example 2 In this example, the thick steel plate 2 is made of 304 stainless steel, with a length × width × height of 300mm × 150mm × 18mm; the thin aluminum alloy plate 1 is made of 2024 aluminum alloy, with a length × width × height of 300mm × 150mm × 2.5mm; and the thick aluminum alloy plate 7 is made of 2024 aluminum alloy, with a length × width × height of 300mm × 150mm × 24mm.

[0052] The forming method includes the following steps: S1. Blank Preparation: Remove oil and oxide film from the surface of thin aluminum alloy plate 1 and roughen one side to a roughness Ra=50μm; remove oil and oxide film from the surface of thick steel plate 2 and roughen one side to a roughness Ra=130μm; remove oil and oxide film from the surface of thick aluminum alloy plate 7 and roughen one side to a roughness Ra=50μm. The initial thickness ratio of thick steel plate 2 to thin aluminum alloy plate 1 is 7.2:1, and the initial thickness ratio of thick aluminum alloy plate 7 to thick steel plate 2 is 1.33:1.

[0053] S2. Low-temperature pre-composite: The thick steel plate 2 treated in S1 and the thin aluminum alloy plate 1 are combined to obtain a steel / thin aluminum alloy pre-composite 3 with the rough surfaces in contact. The pre-composite 3 is heated to 200°C using a No. 1 heating furnace 4 and held for 1.5 hours. It is rolled with a reduction rate of 15% and a two-roll flat rolling mill 5 is used to prepare a steel / thin aluminum alloy pre-composite plate 6 with interfacial mechanical interlocking and local metallurgical bonding.

[0054] S3. Surface treatment of pre-composite plate: Remove oil and oxide film from the surface of the steel / thin aluminum alloy pre-composite plate 6 obtained in step S2, and roughen the aluminum alloy surface to a roughness of Ra=50μm.

[0055] S4. Temperature Control Heating and Billet Assembly: The steel / thin aluminum alloy pre-composite plate 6 treated in S3 and the thick aluminum alloy plate 7 treated in S1 are placed in heating furnace No. 3 (9) and heating furnace No. 2 (8) respectively for heating. The steel / thin aluminum alloy pre-composite plate 6 is heated to the solution temperature of 495℃ and held for 30 min; the thick aluminum alloy plate 7 is heated to the solution temperature of 495℃ and held for 120 min; the heated steel / thin aluminum alloy pre-composite plate 6 and the thick aluminum alloy plate 7 are assembled to obtain a pre-composite plate / aluminum alloy plate billet 10 with the rough surfaces in contact, and held in holding furnace 11 for 15 min.

[0056] S5. Isothermal rolling: The pre-composite plate / aluminum alloy plate billet 10 after S4 heat preservation is fed into the isothermal rolling mill 13 and rolled with a reduction rate of 35% to prepare a rolled thick steel / aluminum alloy composite plate 15; wherein the roll surface temperature of the isothermal rolling mill 13 is 480℃.

[0057] S6. Quenching: At the rolling exit, the thick steel / aluminum alloy composite plate 15 in the S5 rolled state is quenched using the aluminum alloy side spray device 14 and the steel side spray device 16 respectively. The spray pressure on the aluminum alloy side is 0.9MPa, the spray pressure on the steel side is 0.45MPa, and the spray water temperature is 30℃.

[0058] S7. Aging treatment: The thick steel / aluminum alloy composite plate 15 after quenching is subjected to artificial aging treatment. The temperature of the aging furnace 18 is 170℃ and the holding time is 9 hours.

[0059] The final high-performance steel-aluminum alloy composite plate has a total thickness of approximately 27.3 mm, with good interfacial bonding and no warping.

[0060] Example 3 In this embodiment, the thick steel plate 2 is 42CrMo alloy steel with a length × width × height of 400mm × 200mm × 20mm; the thin aluminum alloy plate 1 is 7075 aluminum alloy with a length × width × height of 400mm × 200mm × 4mm; and the thick aluminum alloy plate 7 is 7075 aluminum alloy with a length × width × height of 400mm × 200mm × 30mm.

[0061] The forming method includes the following steps: S1. Blank Preparation: Remove oil and oxide film from the surface of thin aluminum alloy plate 1 and roughen one side to a roughness Ra=100μm; remove oil and oxide film from the surface of thick steel plate 2 and roughen one side to a roughness Ra=250μm; remove oil and oxide film from the surface of thick aluminum alloy plate 7 and roughen one side to a roughness Ra=100μm. The initial thickness ratio of thick steel plate 2 to thin aluminum alloy plate 1 is 5:1, and the initial thickness ratio of thick aluminum alloy plate 7 to thick steel plate 2 is 1.5:1.

[0062] S2. Low-temperature pre-composite: The thick steel plate 2 treated in S1 and the thin aluminum alloy plate 1 are combined to obtain a steel / thin aluminum alloy pre-composite 3 with the rough surfaces in contact. The pre-composite 3 is heated to 250°C using a No. 1 heating furnace 4 and held for 2 hours. It is rolled with a reduction rate of 30% and a two-roll flat rolling mill 5 is used to prepare a steel / thin aluminum alloy pre-composite plate 6 with interfacial mechanical interlocking and local metallurgical bonding.

[0063] S3. Surface treatment of pre-composite plate: Remove oil and oxide film from the surface of the steel / thin aluminum alloy pre-composite plate 6 obtained in step S2, and roughen the aluminum alloy surface to a roughness of Ra=100μm.

[0064] S4. Temperature Control Heating and Billet Assembly: The steel / thin aluminum alloy pre-composite plate 6 treated in S3 and the thick aluminum alloy plate 7 treated in S1 are placed in heating furnace No. 3 (9) and heating furnace No. 2 (8) respectively for heating. The steel / thin aluminum alloy pre-composite plate 6 is heated to the solution temperature of 480℃ and held for 40 min; the thick aluminum alloy plate 7 is heated to the solution temperature of 480℃ and held for 180 min; the heated steel / thin aluminum alloy pre-composite plate 6 and the thick aluminum alloy plate 7 are assembled to obtain a pre-composite plate / aluminum alloy plate billet 10, which is then held in holding furnace 11 for 20 min, so that the rough surfaces of the steel / thin aluminum alloy pre-composite plate 6 and the thick aluminum alloy plate 7 are in contact.

[0065] S5. Isothermal rolling: The pre-composite plate / aluminum alloy plate billet 10 after S4 heat preservation is fed into the isothermal rolling mill 13 and rolled with a reduction rate of 40% to prepare a rolled thick steel / aluminum alloy composite plate 15; wherein the roll surface temperature of the isothermal rolling mill 13 is 500℃.

[0066] S6. Quenching: At the rolling exit, the thick steel / aluminum alloy composite plate 15 in the S5 rolled state is quenched using the aluminum alloy side spray device 14 and the steel side spray device 16 respectively. The spray pressure on the aluminum alloy side is 1.2MPa, the spray pressure on the steel side is 0.6MPa, and the spray water temperature is 40℃.

[0067] S7. Aging treatment: The thick steel / aluminum alloy composite plate 15 after quenching is subjected to artificial aging treatment. The temperature of the aging furnace 18 is 180℃ and the holding time is 12 hours.

[0068] The final high-performance steel-aluminum alloy composite plate has a total thickness of approximately 28.2 mm, with good interfacial bonding and no warping.

[0069] Comparative Example The thick steel plate used is CCSB steel for shipbuilding and marine engineering, with a length × width × height of 200mm × 100mm × 16mm; the thin aluminum alloy plate used is 6061 aluminum alloy, with a length × width × height of 200mm × 100mm × 2mm; the thick aluminum alloy plate used is 6061 aluminum alloy, with a length × width × height of 200mm × 100mm × 20mm.

[0070] The forming method includes the following steps: S1. Blank Preparation: Remove oil and oxide film from the surface of the thin aluminum alloy sheet and roughen one side to a roughness Ra=4μm; remove oil and oxide film from the surface of the thick steel sheet and roughen one side to a roughness Ra=15μm; remove oil and oxide film from the surface of the thick aluminum alloy sheet and roughen one side to a roughness Ra=4μm. The initial thickness ratio of the thick steel sheet to the thin aluminum alloy sheet is 16:1, and the initial thickness ratio of the thick aluminum alloy sheet to the thick steel sheet is 1.25:1.

[0071] S2. Low-temperature pre-composite: The thick steel plate treated by S1 is combined with the thin aluminum alloy plate to obtain a steel / thin aluminum alloy pre-composite and the rough surfaces are brought into contact. The pre-composite is heated to 250°C in a No. 1 heating furnace and held for 1 hour. It is rolled with a reduction rate of 20% and a two-roll flat rolling mill is used to prepare a steel / thin aluminum alloy pre-composite plate with interfacial mechanical interlocking and local metallurgical bonding.

[0072] S3. Surface treatment of pre-composite plate: Remove oil and oxide film from the surface of the steel / thin aluminum alloy pre-composite plate obtained in step S2, and roughen the aluminum alloy surface to a roughness of Ra=4μm.

[0073] S4. Rolling: The pre-composite plate / aluminum alloy plate billet with the rough surface of the steel / thin aluminum alloy plate in contact with the thick aluminum alloy plate is fed into an isothermal rolling mill and rolled at a reduction rate of 30% to produce a rolled thick steel / aluminum alloy composite plate; wherein the roll surface temperature of the isothermal rolling mill is 460℃.

[0074] S5. Solution treatment: The rolled thick steel / aluminum alloy composite plate after S4 treatment is placed in furnace No. 3 and heated to the solution temperature of 520℃, and held for 60 minutes; S6. Quenching: The rolled thick steel / aluminum alloy composite plate after S5 treatment is quenched using an aluminum alloy side spraying device and a steel side spraying device, respectively. The spraying pressure on the aluminum alloy side is 0.6MPa, the spraying pressure on the steel side is 0.3MPa, and the spraying water temperature is 20℃.

[0075] S7. Aging treatment: After all the quenching is completed, the thick steel / aluminum alloy composite plate is subjected to artificial aging treatment. The aging furnace temperature is 160℃ and the holding time is 6 hours.

[0076] The final thick high-performance steel-aluminum alloy composite plate has a total thickness of approximately 22.7 mm, an interfacial shear strength of only 90.1 MPa, an interfacial pull-out strength of approximately 150.6 MPa, and exhibits warping.

[0077] In existing rolling composite processes, the solution treatment temperature range of aluminum alloys largely overlaps with the rapid growth temperature range of intermetallic compounds at the steel / aluminum interface. In traditional processes, if the composite plate is first rolled and then subjected to solution treatment separately, an excessively thick, brittle intermetallic compound layer forms at the interface due to prolonged exposure to high temperatures, severely degrading the bond strength. If solution treatment is omitted, the aluminum alloy matrix cannot achieve age-hardening, resulting in a significant decrease in the overall mechanical properties of the composite plate. The thick, high-performance steel-aluminum alloy composite plate prepared using the method of this invention has a total thickness of approximately 22.3 mm, an interfacial shear strength of 140.5 MPa, and an interfacial pull-out strength of approximately 200.3 MPa, with excellent interfacial bonding and no warping defects. In contrast, a steel-aluminum composite plate prepared using an existing rolling composite method, after solution treatment and subsequent heat treatment, has a total thickness of approximately 22.7 mm, an interfacial shear strength of only 90.1 MPa, and an interfacial pull-out strength of approximately 150.6 MPa, far lower than the interfacial shear strength of the composite plate prepared by the method of this invention. The above comparison fully demonstrates that the present invention effectively solves the contradiction between interfacial bonding and matrix strengthening in the preparation of thick steel / aluminum composite plates through the synergistic process of pre-composite-isothermal rolling and differentiated quenching, while ensuring plate shape quality, and has significant technical advantages.

[0078] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0079] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for temperature-controlled rolling of thick, high-performance steel / aluminum alloy composite plates, characterized in that, The steps are as follows: Pre-composite: A steel / thin aluminum alloy billet (3) is obtained by assembling a thin aluminum alloy plate (1) and a thick steel plate (2). The steel / thin aluminum alloy billet (3) is heated and kept warm, and then rolled to obtain a steel / thin aluminum alloy pre-composite plate (6). The aluminum alloy surface of the steel / thin aluminum alloy pre-composite plate (6) is roughened by grinding. Secondary billet assembly: The steel / thin aluminum alloy pre-composite plate (6) and the thick aluminum alloy plate (7) are heated to the solution temperature and kept warm. The steel / thin aluminum alloy pre-composite plate (6) and the thick aluminum alloy plate (7) are assembled to obtain the pre-composite plate / aluminum alloy plate assembly (10), and then kept warm. Isothermal rolling: The pre-composite plate / aluminum alloy plate billet (10) is fed into the isothermal rolling mill (13) for rolling to obtain a thick steel / aluminum alloy composite plate (15). Among them, the reduction rate of isothermal rolling is 30%-40%, and the temperature is 460-500℃; Post-processing: The steel surface and aluminum alloy surface of the thick steel / aluminum alloy composite plate (15) are quenched and then aged to obtain a thick high-performance steel-aluminum alloy composite plate.

2. The method for temperature-controlled rolling of thick, high-performance steel / aluminum alloy composite plates according to claim 1, characterized in that, Before pre-composite bonding, it is necessary to remove the oil and oxide film from the surfaces of the thin aluminum alloy plate (1), thick steel plate (2) and thick aluminum alloy plate (7) to be bonded, and then roughen the bonding surfaces of the thin aluminum alloy plate (1), thick steel plate (2) and thick aluminum alloy plate (7).

3. The method for temperature-controlled rolling of thick, high-performance steel / aluminum alloy composite plates according to claim 1, characterized in that, The initial thickness ratio of the thick steel plate (2) to the thin aluminum alloy plate (1) is 5:1-20:1, and the initial thickness ratio of the thick aluminum alloy plate (7) to the thick steel plate (2) is 2:1-1:

1.

4. The method for temperature-controlled rolling of thick, high-performance steel / aluminum alloy composite plates according to claim 2, characterized in that, The roughness of the rough surface of the thin aluminum alloy plate (1) and the thick aluminum alloy plate (7) is 4μm≤Ra≤100μm, and the roughness of the rough surface of the thick steel plate (2) is 15μm≤Ra≤250μm.

5. The method for temperature-controlled rolling of thick, high-performance steel / aluminum alloy composite plates according to claim 1, characterized in that, During the pre-composite process, the heating temperature of the steel / thin aluminum alloy billet (3) is 200-250℃, the holding time is 1-2h, and the rolling reduction rate is 15%-30%.

6. The method for temperature-controlled rolling of thick, high-performance steel / aluminum alloy composite plates according to claim 1, characterized in that, After obtaining the steel / thin aluminum alloy pre-composite plate (6) through pre-composite process, the oil and oxide layer on the surface of the steel / thin aluminum alloy pre-composite plate (6) are first removed, and then the aluminum alloy surface of the steel / thin aluminum alloy pre-composite plate (6) is polished to a roughness of 4μm≤Ra≤100μm.

7. The method for temperature-controlled rolling of thick, high-performance steel / aluminum alloy composite plates according to claim 1, characterized in that, During the secondary billet assembly process, the heat preservation time of the steel / thin aluminum alloy pre-composite plate (6) is 20-40 min, the heat preservation time of the thick aluminum alloy plate (7) is 60-180 min, and the heat preservation time of the pre-composite plate / aluminum alloy plate assembly (10) is 10-20 min.

8. The method for temperature-controlled rolling of thick, high-performance steel / aluminum alloy composite plates according to claim 1, characterized in that, During the post-processing, the temperature of the quenching liquid is 20-40℃, the spray pressure on the aluminum alloy side of the thick steel / aluminum alloy composite plate (15) is 0.6-1.2MPa, and the spray pressure on the steel side is 0.3-0.6MPa.

9. The method for temperature-controlled rolling of thick, high-performance steel / aluminum alloy composite plates according to claim 1, characterized in that, During the aging process, the temperature inside the aging furnace (18) is 160-180℃ and the holding time is 6-12h.

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