Preparation method of 7B62 aluminum alloy two-layer composite plate for high-end equipment

Abstract

The invention relates to a preparation method of a 7B62 aluminum alloy two-layer composite plate for high-end equipment, in particular to a preparation method of a 7B62 aluminum alloy two-layer composite plate for high-end equipment. The problem that an existing single-layer 7A52 alloy plate is low in impact strength at the high strain rate is solved. The method comprises the steps of 1, uniform fire; 2, welding; 3, hot rolling; 4, quenching; 5, stretching; 6, aging; and 7, saw cutting. The impact strength of the prepared 7B62 alloy double-layer composite plate is improved by 20% or above compared with that of a 7A52 alloy plate at the high strain rate. And the composite board meets the use requirements of high-end equipment. The method is applied to the field of aluminum alloy composite plate manufacturing.

Description

Technical Field

[0001] The invention relates to a method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment. Background Art

[0002] After entering the 21st century, lightweight aluminum alloy materials represented by 7A52 alloy came on the historical stage. With the continuous improvement of my country's special vehicle lightweight requirements, the microstructure of 7A52 alloy contains multiple phases, such as some coarse second-phase particles. Under high strain rate impact, the deformation coordination between these coarse second-phase particles and the matrix is ​​poor. When the impact stress acts, the matrix deforms, but the coarse second-phase particles are difficult to deform synchronously with the matrix, and it is easy to produce stress concentration at the phase interface. When the stress concentration reaches a certain level, it will cause microcracks, thereby reducing the overall impact strength of the material; and in the high strain rate impact process, the grain boundary is easy to become a weak link. When the stress wave generated by the impact is transmitted to the grain boundary, due to these defects in the grain boundary, the grain boundary will crack prematurely, making it easier for the crack to expand inside the material, reducing the impact strength.

[0003] Moreover, in the rolling process of processing 7A52 alloy into plates, if the rolling process parameters are unreasonable, it may cause uneven structure inside the plate. Under high strain rate impact, the uneven structure of the parts will be subjected to different stress states from other parts, which is easy to produce stress differences, thereby causing cracks to form and expand, and reducing the impact strength; under high strain rate impact, the undesirable structure state cannot effectively convert and absorb the impact energy, which leads to a decrease in impact strength. The combination of factors such as the microstructural characteristics, chemical composition and processing technology of the 7A52 alloy plate leads to its low impact strength at high strain rates. Summary of the invention

[0004] The present invention aims to solve the problem of low impact strength of existing single-layer 7A52 alloy plates at high strain rates, and provides a method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment.

[0005] A method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment is specifically carried out in the following steps:

[0006] 1. The 7B62 alloy ingot is subjected to uniform tempering at a temperature of 450-470°C and a holding time of 26-32 hours. After being taken out of the furnace, it is air-cooled to obtain a uniformly tempered 7B62 alloy ingot;

[0007] 2. sawing and milling the 7B62 alloy ingot after quenching to obtain the 7B62 alloy ingot after milling;

[0008] 3. placing the 7A52 alloy slab and the milled 7B62 alloy ingot in the order of upper 7A52 / lower 7B62, controlling the cladding ratios to be 20% and 80% respectively, and welding the composite billets by riveting to obtain composite billets to be hot rolled;

[0009] 4. heating the composite billet to be hot-rolled to 450-470° C. and keeping the temperature for 10-18 hours, and then hot-rolling the billet to a predetermined thickness to obtain a hot-rolled plate;

[0010] 5. Quenching the hot-rolled plate at a quenching temperature of 450-470°C and a holding time of 1-3h. After being taken out of the furnace, water cooling is performed to obtain a quenched plate;

[0011] 6. Stretching the quenched plate, the stretching amount is 1 to 3% of the length of the quenched plate, to obtain a stretched plate;

[0012] 7. Aging the stretched plate at a temperature of 100-120°C and a holding time of 24-30 hours. After being taken out of the furnace, air-cooling is performed to obtain an aged plate.

[0013] 8. Saw the aging plate according to actual needs to obtain 7B62 aluminum alloy two-layer composite plate for high-end equipment.

[0014] The beneficial effects of the present invention are:

[0015] The new 7B62 aluminum alloy two-layer composite plate prepared by the present invention has a tensile strength of 590-610MPa, a yield strength of 550-570MPa, and an elongation of 10.0-12.0%; the tensile strength is increased by 30-50MPa, the yield strength is increased by 20-40MPa, and the elongation is maintained at the same level compared with the single-layer 7A52 alloy plate of the same specification. The new 7B62 aluminum alloy two-layer composite plate has a compressive strength of 670-690MPa, a yield strength of 650-670MPa, and a fracture strain of 11.0-13.0% at a high strain rate; the tensile strength is increased by 23-28%, the yield strength is increased by 20-25%, and the fracture strain is maintained at the same level compared with the single-layer 7A52 alloy plate of the same specification. The invention aims to improve the impact resistance of aluminum alloy plates at high strain rates, apply them to the field of special vehicle manufacturing, improve the safety performance of special combat vehicles, replace the application of single-layer 7A52 alloy plates, and realize the replacement of new materials. The present invention breaks through the technical bottleneck problem of low impact strength of single-layer 7A52 alloy plate at high strain rate, and will be more conducive to the promotion and use of 7B62 aluminum alloy two-layer composite plates for high-end equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a photo of the 7B62 alloy ingot prepared in Example 1;

[0017] Figure 2This is a photo of the 7B62 aluminum alloy two-layer composite plate for high-end equipment prepared in Example 1. DETAILED DESCRIPTION

[0018] Specific implementation method 1: In this implementation method, a method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment is specifically carried out in the following steps:

[0019] 1. The 7B62 alloy ingot is subjected to uniform tempering at a temperature of 450-470°C and a holding time of 26-32 hours. After being taken out of the furnace, it is air-cooled to obtain a uniformly tempered 7B62 alloy ingot;

[0020] 2. sawing and milling the 7B62 alloy ingot after quenching to obtain the 7B62 alloy ingot after milling;

[0021] 3. placing the 7A52 alloy slab and the milled 7B62 alloy ingot in the order of upper 7A52 / lower 7B62, controlling the cladding ratios to be 20% and 80% respectively, and welding the composite billets by riveting to obtain composite billets to be hot rolled;

[0022] 4. heating the composite billet to be hot-rolled to 450-470° C. and keeping the temperature for 10-18 hours, and then hot-rolling the billet to a predetermined thickness to obtain a hot-rolled plate;

[0023] 5. Quenching the hot-rolled plate at a quenching temperature of 450-470°C and a holding time of 1-3h. After being taken out of the furnace, water cooling is performed to obtain a quenched plate;

[0024] 6. Stretching the quenched plate, the stretching amount is 1 to 3% of the length of the quenched plate, to obtain a stretched plate;

[0025] 7. Aging the stretched plate at a temperature of 100-120°C and a holding time of 24-30 hours. After being taken out of the furnace, air-cooling is performed to obtain an aged plate.

[0026] 8. Saw the aging plate according to actual needs to obtain 7B62 aluminum alloy two-layer composite plate for high-end equipment.

[0027] This implementation method first performs annealing on the 7B62 alloy ingot, which can effectively eliminate the residual stress inside the alloy ingot and make the internal structure of the material more uniform; under high strain rate impact, the uniform structure can make the stress more evenly distributed inside the material, avoiding defects such as cracks caused by local stress concentration, thereby laying the foundation for improving impact strength.

[0028] After the annealing treatment, the 7B62 alloy ingot is air-cooled and has a more stable microstructure, which is very important for the subsequent cladding with the 7A52 alloy slab and the performance improvement of the entire clad plate.

[0029] Sawing and milling the 7B62 alloy ingot after annealing can remove the defects and impurities that may exist on the surface of the ingot and obtain a flat and smooth surface. Good surface quality is not only conducive to better bonding with the 7A52 alloy slab, but also can reduce stress concentration caused by surface defects during subsequent processing, thereby reducing the possibility of cracks and expansion under high strain rate impact, which helps to improve the impact resistance of the composite plate.

[0030] The 7A52 alloy slab and the milled 7B62 alloy ingot are placed in the order of upper 7A52 / lower 7B62, and the coating ratio is controlled to be 20% and 80%. This composite structure design makes full use of the advantages of the two alloys. The 7A52 alloy has higher strength, while the 7B62 alloy often has better toughness and other properties. Through reasonable coating ratio control, during high strain rate impact, the 7B62 alloy layer with better toughness (accounting for 80%) can absorb a large amount of impact energy and play a buffering role, thereby reducing the impact stress on the 7A52 alloy layer (accounting for 20%) with higher strength but relatively weak impact resistance, effectively improving the impact strength of the overall composite plate.

[0031] The composite blanks are welded by riveting, so that the two layers of materials are closely connected together to form a strong bonding interface. Under high strain rate impact, the strong bonding interface can effectively transfer stress and prevent delamination or separation between the two layers of materials, thus ensuring the integrity of the composite plate and further enhancing its impact resistance.

[0032] Hot rolling process:

[0033] The composite billet to be hot-rolled is heated to 450-470℃ and kept warm for 10-18h before hot rolling. The heat preservation process ensures that the inside of the billet is evenly heated, so that the material reaches a suitable organizational structure before hot rolling. The hot rolling operation causes the material to undergo plastic deformation, further improving the organizational structure of the material, and increasing the density and strength of the material. At the same time, the hot rolling process also makes the bond between the two layers of material closer, enhances the integrity of the composite plate, enables it to better withstand impact stress under high strain rate impact, and improves impact resistance.

[0034] Quenching the hot-rolled plate allows the strengthening phase in the alloy to fully dissolve and form a supersaturated solid solution, which significantly improves the strength and hardness of the material. Under high strain rate impact, high-strength, high-hardness materials can better resist impact stress, reduce the possibility of deformation and damage, and help improve the impact strength of the composite plate.

[0035] Stretching the quenched plate can eliminate the residual stress inside the material and improve the plasticity and toughness of the material. Under high strain rate impact, good plasticity and toughness can enable the material to better absorb impact energy, reduce the generation and expansion of cracks, and thus improve the impact strength.

[0036] Aging the tensile plate can cause the strengthening phase in the supersaturated solid solution to precipitate, further improving the strength and hardness of the material. At the same time, reasonable aging treatment can also optimize the material's organizational structure and improve the material's fatigue resistance and impact resistance.

[0037] This embodiment plays a positive role in improving the impact strength of the composite plate at high strain rates from different aspects, from the pretreatment of raw materials, the design of the composite structure to the implementation of thermal processing and heat treatment processes, thereby effectively solving the problem of low impact strength of the existing single-layer 7A52 alloy plate at high strain rates.

[0038] Specific embodiment 2: This embodiment is different from specific embodiment 1 in that the mass percentage of each element in the 7B62 alloy ingot described in step 1 is as follows: Si: 0.05-0.1%, Fe: 0.05-0.1%, Cu: 0.5-1.0%, Mn: 1.0-1.5%, Mg: 2.5-3.5%, Zn: 8.0-8.5%, Ti: 0.05-0.15%, Zr: 0.05-0.15%, single impurity <0.05%, total impurity <0.15% and the balance Al. The rest is the same as specific embodiment 1.

[0039] Specific embodiment 3: This embodiment is different from the specific embodiment 2 in that: the preparation method of the 7B62 alloy ingot described in step 1 is carried out according to the following steps:

[0040] 1. According to the mass percentage of each element: Si: 0.05-0.1%, Fe: 0.05-0.1%, Cu: 0.5-1.0%, Mn: 1.0-1.5%, Mg: 2.5-3.5%, Zn: 8.0-8.5%, Ti: 0.05-0.15%, Zr: 0.05-0.15%, single impurity <0.05%, total impurity <0.15% and the balance Al, weigh pure aluminum ingots, pure magnesium ingots, pure zinc ingots, aluminum-zirconium master alloy, aluminum-manganese master alloy, aluminum-copper master alloy and aluminum-titanium-boron grain refiner;

[0041] 2. Add the weighed pure aluminum ingot, pure zinc ingot, aluminum-zirconium master alloy, aluminum-manganese master alloy and aluminum-copper master alloy into a smelting furnace, set the smelting temperature to 720-780°C, add the pure magnesium ingot after melting, stirring and deslagging, and add No. 1 covering agent, smelt for 15-30 minutes, and then use Ar-Cl2 mixed gas to refine until the hydrogen content in every 100 grams of aluminum alloy melt is ≤0.25mL, and then stand for 30 minutes to obtain aluminum alloy melt;

[0042] 3. The aluminum alloy melt is filtered through 30ppi and 50ppi ceramic filters in turn, and then poured into the crystallizer, and at the same time, the aluminum titanium boron grain refiner is inserted into the flow channel and evenly melted into the aluminum alloy melt;

[0043] Fourth, after all the aluminum alloy melt flows into the crystallizer, casting is performed at a temperature of 690-720° C., a water pressure of 0.05-0.10 MPa, and a speed of 40-60 mm / min to obtain a 7B62 alloy ingot. The rest is the same as the second embodiment.

[0044] Specific embodiment 4: This embodiment is different from specific embodiment 3 in that the thickness of the 7B62 alloy ingot in step 4 is 420 mm, the width is 1620 mm, and the length is 4000-6000 mm. Other aspects are the same as specific embodiment 3.

[0045] Specific embodiment 5: This embodiment is different from the specific embodiment 1 in that: the preparation method of the 7A52 alloy slab described in step 3 is carried out according to the following steps:

[0046] 1. According to the mass percentage of each element: Si≤0.25%, Fe≤0.30%, Cu: 0.05-0.20%, Mn: 0.20-0.50%, Mg: 2.0-2.8%, Zn: 4.0-4.8%, Cr: 0.15-0.25%, Zr: 0.05-0.15%, Ti: 0.05-0.18%, and the balance Al ratio, weigh pure aluminum ingots, pure magnesium ingots, pure zinc ingots, aluminum-zirconium master alloys, aluminum-manganese master alloys, aluminum-copper master alloys, aluminum-chromium master alloys, and aluminum-titanium-boron grain refiners;

[0047] 2. Add the weighed pure aluminum ingot, pure zinc ingot, aluminum-zirconium master alloy, aluminum-manganese master alloy, aluminum-copper master alloy and aluminum-chromium master alloy into a smelting furnace, set the smelting temperature to 700-760°C, add the pure magnesium ingot after melting, stirring and deslagging, and add No. 1 covering agent, smelt for 15-30 minutes, and then use Ar-Cl2 mixed gas to refine until the hydrogen content in every 100 grams of aluminum alloy melt is ≤0.25mL, and then stand for 30 minutes to obtain aluminum alloy melt;

[0048] 3. The aluminum alloy melt is filtered through 30ppi and 50ppi ceramic filters in turn, and then poured into the crystallizer, and at the same time, the aluminum titanium boron grain refiner is inserted into the flow channel and evenly melted into the aluminum alloy melt;

[0049] 4. After all the aluminum alloy melt flows into the crystallizer, casting is performed at a temperature of 690-720° C., a water pressure of 0.05-0.10 MPa, and a speed of 40-60 mm / min to obtain a 7A52 alloy ingot;

[0050] 5. After milling the 7A52 alloy ingot, heat it to 450-480°C, perform hot rolling, hot roll it to a predetermined thickness to obtain a hot rolled slab, and saw it to a predetermined length and width to obtain a 7A52 alloy slab. The rest is the same as the first embodiment.

[0051] Specific embodiment 6: This embodiment is different from specific embodiment 3 or 5 in that: the aluminum-zirconium master alloy is Al-3% Zr master alloy, the aluminum-manganese master alloy is Al-10% Mn alloy, the aluminum-copper master alloy is Al-40% Cu master alloy, and the aluminum-titanium-boron grain refiner is aluminum-titanium-boron alloy Al-5% Ti-1% B. The rest is the same as specific embodiment 3 or 5.

[0052] Specific embodiment 7: This embodiment is different from specific embodiment 3 or 5 in that: the No. 1 covering agent is No. 1 flux, which is composed of 50% KCl, 26% NaCl and 24% NaAlF6 by weight. The rest is the same as specific embodiment 3 or 5.

[0053] Specific implementation eight: This implementation differs from specific implementation seven in that the amount of the No. 1 covering agent used is 0.4% to 0.6% of the total mass of the molten metal in the smelting furnace. Other aspects are the same as specific implementation seven.

[0054] Specific embodiment 9: This embodiment is different from specific embodiment 3 or 5 in that the Ar-Cl2 mixed gas is a mixture of argon gas and chlorine gas in a volume ratio of (31-33.5): 1. Other aspects are the same as specific embodiment 3 or 5.

[0055] Specific embodiment 10: This embodiment is different from specific embodiment 3 or 5 in that the speed of inserting the aluminum titanium boron grain refiner into the flow channel is 400 mm / min. Other aspects are the same as specific embodiment 3 or 5.

[0056] Specific embodiment 11: This embodiment is different from the specific embodiment 2 in that the mass percentages of the elements in the 7B62 alloy ingot in step 1 are as follows: Si: 0.07%, Fe: 0.08%, Cu: 0.7%, Mn: 1.3%, Mg: 3.0%, Zn: 8.3%, Ti: 0.10%, Zr: 0.11%, single impurities <0.05%, total impurities <0.15% and the balance Al. The rest is the same as the specific embodiment 2.

[0057] Specific embodiment 12: This embodiment differs from specific embodiment 4 in that the thickness of the 7B62 alloy ingot in step 4 is 420 mm, the width is 1620 mm, and the length is 5000 mm. The rest is the same as specific embodiment 4.

[0058] Specific embodiment 13: This embodiment is different from specific embodiment 5 in that: in step 1, pure aluminum ingots, pure magnesium ingots, pure zinc ingots, aluminum-zirconium master alloys, aluminum-manganese master alloys, aluminum-copper master alloys, aluminum-chromium master alloys and aluminum-titanium-boron grain refiners are weighed according to the mass percentage of each element: Si: 0.10%, Fe: 0.15%, Cu: 0.16%, Mn: 0.42%, Mg: 2.6%, Zn: 4.6%, Cr: 0.18%, Zr: 0.12%, Ti: 0.11%, single impurities <0.05%, total impurities <0.15% and the balance Al ratio. The rest is the same as specific embodiment 5.

[0059] Specific embodiment 14: This embodiment differs from specific embodiment 5 in that: in step 5, the thickness of the 7A52 alloy slab is 420 mm, the width is 1450 mm, and the length is 5000 mm. The rest is the same as specific embodiment 5.

[0060] The following examples are used to verify the beneficial effects of the present invention:

[0061] Embodiment 1: A method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment is specifically carried out in the following steps:

[0062] 1. The 7B62 alloy ingot is subjected to uniform tempering at a temperature of 450-470°C and a holding time of 26-32 hours. After being taken out of the furnace, it is air-cooled to obtain a uniformly tempered 7B62 alloy ingot;

[0063] 2. sawing and milling the 7B62 alloy ingot after quenching to obtain the 7B62 alloy ingot after milling;

[0064] 3. placing the 7A52 alloy slab and the milled 7B62 alloy ingot in the order of upper 7A52 / lower 7B62, controlling the cladding ratios to be 20% and 80% respectively, and welding the composite billets by riveting to obtain composite billets to be hot rolled;

[0065] 4. heating the composite billet to be hot-rolled to 450-470° C. and keeping the temperature for 10-18 hours, and then hot-rolling the billet to a predetermined thickness to obtain a hot-rolled plate;

[0066] 5. Quenching the hot-rolled plate at a quenching temperature of 450-470°C and a holding time of 1-3h. After being taken out of the furnace, water cooling is performed to obtain a quenched plate;

[0067] 6. Stretching the quenched plate, the stretching amount is 1 to 3% of the length of the quenched plate, to obtain a stretched plate;

[0068] 7. Aging the stretched plate at a temperature of 100-120°C and a holding time of 24-30 hours. After being taken out of the furnace, air-cooling is performed to obtain an aged plate.

[0069] 8. Saw the aging plate according to actual needs to obtain 7B62 aluminum alloy two-layer composite plate for high-end equipment.

[0070] The preparation method of the 7B62 alloy ingot is carried out according to the following steps:

[0071] A. Weigh pure aluminum ingots, pure magnesium ingots, pure zinc ingots, aluminum-zirconium master alloys, aluminum-manganese master alloys, aluminum-copper master alloys and aluminum-titanium-boron grain refiners according to the mass percentage of each element: Si: 0.08%, Fe: 0.08%, Cu: 0.8%, Mn: 1.2%, Mg: 2.8%, Zn: 8.2%, Ti: 0.11%, Zr: 0.10%, single impurities < 0.05%, total impurities < 0.15% and the balance Al;

[0072] B. Add the weighed pure aluminum ingot, pure zinc ingot, aluminum-zirconium master alloy, aluminum-manganese master alloy and aluminum-copper master alloy into a smelting furnace, set the smelting temperature to 720-780° C., add the pure magnesium ingot after melting, stirring and deslagging, and add No. 1 covering agent, smelt for 15-30 minutes, and then use Ar-Cl2 mixed gas to refine until the hydrogen content in every 100 grams of aluminum alloy melt is ≤0.25mL, and then stand for 30 minutes to obtain aluminum alloy melt;

[0073] C. The aluminum alloy melt is filtered through 30ppi and 50ppi ceramic filter sheets in turn, and then poured into a crystallizer, and at the same time, an aluminum-titanium-boron grain refiner is inserted into the launder and uniformly melted into the aluminum alloy melt;

[0074] D. After all the aluminum alloy melt flows into the crystallizer, casting is carried out at a temperature of 700°C, a water pressure of 0.06 MPa, and a speed of 50 mm / min to obtain a 7B62 alloy ingot.

[0075] The preparation method of the 7A52 alloy slab is carried out according to the following steps:

[0076] A. Weigh pure aluminum ingots, pure magnesium ingots, pure zinc ingots, aluminum-zirconium master alloys, aluminum-manganese master alloys, aluminum-copper master alloys, aluminum-chromium master alloys and aluminum-titanium-boron grain refiners according to the mass percentage of each element: Si: 0.11%, Fe: 0.15%, Cu: 0.17%, Mn: 0.39%, Mg: 2.3%, Zn: 4.5%, Cr: 0.17%, Zr: 0.10%, Ti: 0.09%, single impurity < 0.05% and the balance is Al;

[0077] B. Add the weighed pure aluminum ingot, pure zinc ingot, aluminum-zirconium master alloy, aluminum-manganese master alloy, aluminum-copper master alloy and aluminum-chromium master alloy into a smelting furnace, set the smelting temperature to 700-760° C., add the pure magnesium ingot after melting, stirring and deslagging, and add No. 1 covering agent, smelt for 15-30 minutes, and then use Ar-Cl2 mixed gas to refine until the hydrogen content in every 100 grams of aluminum alloy melt is ≤0.25mL, and then stand for 30 minutes to obtain aluminum alloy melt;

[0078] C. The aluminum alloy melt is filtered through 30ppi and 50ppi ceramic filter sheets in turn, and then poured into a crystallizer, and at the same time, an aluminum-titanium-boron grain refiner is inserted into the launder and uniformly melted into the aluminum alloy melt;

[0079] D. After all the aluminum alloy melt flows into the crystallizer, casting is performed under the conditions of a temperature of 696° C., a water pressure of 0.05 MPa, and a speed of 45 mm / min to obtain a 7A52 alloy ingot;

[0080] E. After milling the 7A52 alloy ingot, heat it to 450-480°C, and hot roll it to a predetermined thickness to obtain a hot-rolled slab, which is then sawn to a predetermined length and width to obtain a 7A52 alloy slab.

[0081] The tensile strength of the 7B62 aluminum alloy two-layer composite plate prepared in this embodiment is 593MPa, the yield strength is 558MPa, and the elongation is 11.8%. Compared with the single-layer 7A52 alloy plate of the same specification, the tensile strength is increased by 35MPa, the yield strength is increased by 25MPa, and the elongation remains at the same level. The compressive strength of the 7B62 aluminum alloy two-layer composite plate at high strain rate is 675MPa, the yield strength is 656MPa, and the fracture strain is 12.6%. Compared with the single-layer 7A52 alloy plate of the same specification, the tensile strength is increased by 23%, the yield strength is increased by 20%, and the fracture strain is maintained at the same level.

[0082] Embodiment 2: A method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment is specifically carried out according to the following steps:

[0083] 1. The 7B62 alloy ingot is subjected to uniform tempering at a temperature of 450-470°C and a holding time of 26-32 hours. After being taken out of the furnace, it is air-cooled to obtain a uniformly tempered 7B62 alloy ingot;

[0084] 2. sawing and milling the 7B62 alloy ingot after quenching to obtain the 7B62 alloy ingot after milling;

[0085] 3. placing the 7A52 alloy slab and the milled 7B62 alloy ingot in the order of upper 7A52 / lower 7B62, controlling the cladding ratios to be 20% and 80% respectively, and welding the composite billets by riveting to obtain composite billets to be hot rolled;

[0086] 4. heating the composite billet to be hot-rolled to 450-470° C. and keeping the temperature for 10-18 hours, and then hot-rolling the billet to a predetermined thickness to obtain a hot-rolled plate;

[0087] 5. Quenching the hot-rolled plate at a quenching temperature of 450-470°C and a holding time of 1-3h. After being taken out of the furnace, water cooling is performed to obtain a quenched plate;

[0088] 6. Stretching the quenched plate, the stretching amount is 1 to 3% of the length of the quenched plate, to obtain a stretched plate;

[0089] 7. Aging the stretched plate at a temperature of 100-120°C and a holding time of 24-30 hours. After being taken out of the furnace, air-cooling is performed to obtain an aged plate.

[0090] 8. Saw the aging plate according to actual needs to obtain 7B62 aluminum alloy two-layer composite plate for high-end equipment.

[0091] The preparation method of the 7B62 alloy ingot is carried out according to the following steps:

[0092] A. Weigh pure aluminum ingots, pure magnesium ingots, pure zinc ingots, aluminum-zirconium master alloys, aluminum-manganese master alloys, aluminum-copper master alloys and aluminum-titanium-boron grain refiners according to the mass percentage of each element: Si: 0.08%, Fe: 0.09%, Cu: 0.9%, Mn: 1.4%, Mg: 3.4%, Zn: 8.4%, Ti: 0.11%, Zr: 0.12%, single impurities < 0.05%, total impurities < 0.15% and the balance Al;

[0093] B. Add the weighed pure aluminum ingot, pure zinc ingot, aluminum-zirconium master alloy, aluminum-manganese master alloy and aluminum-copper master alloy into a smelting furnace, set the smelting temperature to 720-780° C., add the pure magnesium ingot after melting, stirring and deslagging, and add No. 1 covering agent, smelt for 15-30 minutes, and then use Ar-Cl2 mixed gas to refine until the hydrogen content in every 100 grams of aluminum alloy melt is ≤0.25mL, and then stand for 30 minutes to obtain aluminum alloy melt;

[0094] C. The aluminum alloy melt is filtered through 30ppi and 50ppi ceramic filter sheets in turn, and then poured into a crystallizer, and at the same time, an aluminum-titanium-boron grain refiner is inserted into the launder and uniformly melted into the aluminum alloy melt;

[0095] D. After all the aluminum alloy melt flows into the crystallizer, casting is carried out at a temperature of 710°C, a water pressure of 0.08 MPa, and a speed of 55 mm / min to obtain a 7B62 alloy ingot.

[0096] The preparation method of the 7A52 alloy slab is carried out according to the following steps:

[0097] A. Weigh pure aluminum ingots, pure magnesium ingots, pure zinc ingots, aluminum-zirconium master alloys, aluminum-manganese master alloys, aluminum-copper master alloys, aluminum-chromium master alloys and aluminum-titanium-boron grain refiners according to the mass percentage of each element: Si: 0.15%, Fe: 0.17%, Cu: 0.18%, Mn: 0.47%, Mg: 2.6%, Zn: 4.7%, Cr: 0.20%, Zr: 0.11%, Ti: 0.11%, single impurity < 0.05% and the balance is Al;

[0098] B. Add the weighed pure aluminum ingot, pure zinc ingot, aluminum-zirconium master alloy, aluminum-manganese master alloy, aluminum-copper master alloy and aluminum-chromium master alloy into a smelting furnace, set the smelting temperature to 700-760° C., add the pure magnesium ingot after melting, stirring and deslagging, and add No. 1 covering agent, smelt for 15-30 minutes, and then use Ar-Cl2 mixed gas to refine until the hydrogen content in every 100 grams of aluminum alloy melt is ≤0.25mL, and then stand for 30 minutes to obtain aluminum alloy melt;

[0099] C. The aluminum alloy melt is filtered through 30ppi and 50ppi ceramic filter sheets in turn, and then poured into a crystallizer, and at the same time, an aluminum-titanium-boron grain refiner is inserted into the launder and uniformly melted into the aluminum alloy melt;

[0100] D. After all the aluminum alloy melt flows into the crystallizer, casting is performed under the conditions of a temperature of 708° C., a water pressure of 0.06 MPa, and a speed of 50 mm / min to obtain a 7A52 alloy ingot;

[0101] E. After milling the 7A52 alloy ingot, heat it to 450-480°C, and hot roll it to a predetermined thickness to obtain a hot-rolled slab, which is then sawn to a predetermined length and width to obtain a 7A52 alloy slab.

[0102] The tensile strength of the 7B62 aluminum alloy two-layer composite plate prepared in this embodiment is 609MPa, the yield strength is 568MPa, and the elongation is 10.6%. Compared with the single-layer 7A52 alloy plate of the same specification, the tensile strength is increased by 45MPa, the yield strength is increased by 35MPa, and the elongation remains at the same level. The compressive strength of the 7B62 aluminum alloy two-layer composite plate at high strain rate is 688MPa, the yield strength is 668MPa, and the fracture strain is 11.6%. Compared with the single-layer 7A52 alloy plate of the same specification, the tensile strength is increased by 28%, the yield strength is increased by 25%, and the fracture strain is maintained at the same level.

Claims

1. A method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment, characterized in that The preparation method of 7B62 aluminum alloy two-layer composite plate for high-end equipment is specifically carried out in the following steps:

1. The 7B62 alloy ingot is subjected to uniform tempering at a temperature of 450-470°C and a holding time of 26-32 hours. After being taken out of the furnace, it is air-cooled to obtain a uniformly tempered 7B62 alloy ingot; 2. sawing and milling the 7B62 alloy ingot after quenching to obtain the 7B62 alloy ingot after milling; 3. placing the 7A52 alloy slab and the milled 7B62 alloy ingot in the order of upper 7A52 / lower 7B62, controlling the cladding ratios to be 20% and 80% respectively, and welding the composite billets by riveting to obtain composite billets to be hot rolled; 4. heating the composite billet to be hot-rolled to 450-470° C. and keeping the temperature for 10-18 hours, and then hot-rolling the billet to a predetermined thickness to obtain a hot-rolled plate; 5. Quenching the hot-rolled plate at a quenching temperature of 450-470°C and a holding time of 1-3h. After being taken out of the furnace, water cooling is performed to obtain a quenched plate; 6. Stretching the quenched plate, the stretching amount is 1 to 3% of the length of the quenched plate, to obtain a stretched plate; 7. Aging the stretched plate at a temperature of 100-120°C and a holding time of 24-30 hours. After being taken out of the furnace, air-cooling is performed to obtain an aged plate.

8. Saw the aging plate according to actual needs to obtain 7B62 aluminum alloy two-layer composite plate for high-end equipment.

2. The method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment according to claim 1, characterized in that The mass percentages of the elements in the 7B62 alloy ingot described in step 1 are as follows: Si: 0.05-0.1%, Fe: 0.05-0.1%, Cu: 0.5-1.0%, Mn: 1.0-1.5%, Mg: 2.5-3.5%, Zn: 8.0-8.5%, Ti: 0.05-0.15%, Zr: 0.05-0.15%, single impurities <0.05%, total impurities <0.15% and the balance Al.

3. The method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment according to claim 2, characterized in that The method for preparing the 7B62 alloy ingot described in step 1 is carried out according to the following steps:

1. According to the mass percentage of each element: Si: 0.05-0.1%, Fe: 0.05-0.1%, Cu: 0.5-1.0%, Mn: 1.0-1.5%, Mg: 2.5-3.5%, Zn: 8.0-8.5%, Ti: 0.05-0.15%, Zr: 0.05-0.15%, single impurity <0.05%, total impurity <0.15% and the balance Al, weigh pure aluminum ingots, pure magnesium ingots, pure zinc ingots, aluminum-zirconium master alloy, aluminum-manganese master alloy, aluminum-copper master alloy and aluminum-titanium-boron grain refiner; 2. Add the weighed pure aluminum ingot, pure zinc ingot, aluminum-zirconium master alloy, aluminum-manganese master alloy and aluminum-copper master alloy into a smelting furnace, set the smelting temperature to 720-780°C, add the pure magnesium ingot after melting, stirring and deslagging, and add No. 1 covering agent, smelt for 15-30 minutes, and then use Ar-Cl2 mixed gas to refine until the hydrogen content in every 100 grams of aluminum alloy melt is ≤0.25mL, and then stand for 30 minutes to obtain aluminum alloy melt; 3. The aluminum alloy melt is filtered through 30ppi and 50ppi ceramic filters in turn, and then poured into the crystallizer, and at the same time, the aluminum titanium boron grain refiner is inserted into the flow channel and evenly melted into the aluminum alloy melt; 4. After all the aluminum alloy melt flows into the crystallizer, casting is carried out at a temperature of 690-720°C, a water pressure of 0.05-0.10 MPa, and a speed of 40-60 mm / min to obtain a 7B62 alloy ingot.

4. The method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment according to claim 3, characterized in that The 7B62 alloy ingot in step 4 has a thickness of 420 mm, a width of 1620 mm, and a length of 4000 to 6000 mm.

5. The method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment according to claim 1, characterized in that The preparation method of the 7A52 alloy slab described in step 3 is carried out according to the following steps:

1. According to the mass percentage of each element: Si≤0.25%, Fe≤0.30%, Cu: 0.05-0.20%, Mn: 0.20-0.50%, Mg: 2.0-2.8%, Zn: 4.0-4.8%, Cr: 0.15-0.25%, Zr: 0.05-0.15%, Ti: 0.05-0.18%, and the balance Al ratio, weigh pure aluminum ingots, pure magnesium ingots, pure zinc ingots, aluminum-zirconium master alloys, aluminum-manganese master alloys, aluminum-copper master alloys, aluminum-chromium master alloys, and aluminum-titanium-boron grain refiners; 2. Add the weighed pure aluminum ingot, pure zinc ingot, aluminum-zirconium master alloy, aluminum-manganese master alloy, aluminum-copper master alloy and aluminum-chromium master alloy into a smelting furnace, set the smelting temperature to 700-760°C, add the pure magnesium ingot after melting, stirring and deslagging, and add No. 1 covering agent, smelt for 15-30 minutes, and then use Ar-Cl2 mixed gas to refine until the hydrogen content in every 100 grams of aluminum alloy melt is ≤0.25mL, and then stand for 30 minutes to obtain aluminum alloy melt; 3. The aluminum alloy melt is filtered through 30ppi and 50ppi ceramic filters in turn, and then poured into the crystallizer, and at the same time, the aluminum titanium boron grain refiner is inserted into the flow channel and evenly melted into the aluminum alloy melt; 4. After all the aluminum alloy melt flows into the crystallizer, casting is performed at a temperature of 690-720° C., a water pressure of 0.05-0.10 MPa, and a speed of 40-60 mm / min to obtain a 7A52 alloy ingot; 5. After the 7A52 alloy ingot is milled, it is heated to 450-480° C. and hot rolled to a predetermined thickness to obtain a hot-rolled slab, which is sawn to a predetermined length and width to obtain a 7A52 alloy slab.

6. The method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment according to claim 3 or 5, characterized in that The aluminum-zirconium master alloy is an Al-3% Zr master alloy, the aluminum-manganese master alloy is an Al-10% Mn alloy, the aluminum-copper master alloy is an Al-40% Cu master alloy, and the aluminum-titanium-boron grain refiner is an aluminum-titanium-boron alloy Al-5% Ti-1% B.

7. The method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment according to claim 3 or 5, characterized in that The No. 1 covering agent is No. 1 flux, which is composed of 50% KCl, 26% NaCl and 24% NaAlF6 by weight.

8. The method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment according to claim 7, characterized in that The usage of the No. 1 covering agent is 0.4% to 0.6% of the total mass of the molten metal in the smelting furnace.

9. The method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment according to claim 3 or 5, characterized in that The Ar-Cl2 mixed gas is formed by mixing argon gas and chlorine gas in a volume ratio of (31-33.5):

1.

10. The method for preparing a 7B62 aluminum alloy two-layer composite plate for high-end equipment according to claim 3 or 5, characterized in that The speed at which the aluminum-titanium-boron grain refiner is inserted into the flow channel is 400 mm / min.

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