Aluminum alloy flat ingot and preparation method thereof, aluminum alloy plate and preparation method thereof

Abstract

The present invention provides an aluminum alloy slab, a preparation method thereof, and an aluminum alloy plate. The aluminum alloy slab comprises, by mass percentage, the following components: Mg content of 4.30% to 5.20%, Mn content of 0.40% to 0.60%, La content of 0.05% to 0.15%, Si content ≤0.25%, Zn content ≤0.25%, Cr content ≤0.20%, Ti content ≤0.15%, Fe content ≤0.50%, the total of unavoidable impurities ≤0.15%, and the balance being Al. At 1 / 4 the thickness of the aluminum alloy slab, the average grain size is ≤90 μm, the maximum size of the intermetallic compounds is ≤60 μm, and the average size of the intermetallic compounds is ≤15 μm. The aluminum alloy slab has excellent mechanical properties and processing resistance, and the ingot can be used to process aluminum alloy plate materials, etc., with high quality and yield.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy preparation, and in particular to an aluminum alloy slab and a preparation method thereof, and an aluminum alloy plate and a preparation method thereof. Background Art

[0002] 5083 aluminum alloy, with its excellent strength, corrosion resistance, and weldability, is widely used in maritime, automotive, aerospace, transportation, pressure vessels, and refrigeration equipment. However, a long-standing problem in the industrial production of high-magnesium aluminum alloys, especially large-sized ingots with a width of 1000mm or more, is the appearance of ring-shaped segregation on the ingot's cross-section. This phenomenon manifests as distinct color bands, accompanied by uneven alloy composition and the presence of large grains. This segregation not only affects the subsequent processing of the ingot, such as cracking during forging, but also causes color variations on the product surface after anodizing. In severe cases, this can affect the product's aesthetics and performance, thereby reducing yield and market competitiveness.

[0003] Ring segregation is different from conventional macrosegregation, which does not show obvious coarse grain bands in low-magnification inspection, while ring segregation is clearly visible on the cross-section of the ingot. The ring segregation area is often accompanied by coarse compounds and high hydrogen content, the latter of which may cause loose defects. Although there are many diversion devices in the prior art to improve the fluidity and composition uniformity of alloy melts, such as spin diversion bags, double diversion devices, and diversion bags with reinforcing ribs and anti-deformation designs, these technologies have not systematically studied the effects of diversion structure and smelting and casting processes on ingot ring segregation, compound size, and hydrogen content, nor have they selected matching diversion bag size and structure according to the size of the ingot, which limits their role in suppressing ring segregation, refining grains, and eliminating coarse compounds.

[0004] Specifically, existing patents such as "A spinning diverter bag and aluminum alloy casting method" (CN 110976791 A), "Device and method for semi-continuous casting of ultra-wide aluminum alloy slabs" (CN 112548055 A), and "Casting diverter and design method of casting diverter" (CN 117548635 A) mainly focus on improving melt fluidity or improving macrosegregation, but fail to effectively solve the problem of insufficient filling at the corners and center of large surfaces of large ingots, nor do they involve methods to reduce the number, size and aggregation size of loose materials.

[0005] In summary, the existing technology lacks an effective solution to comprehensively improve the ring segregation problem of large-scale high-magnesium aluminum alloy ingots, as well as the resulting problems of uneven alloy composition distribution, uneven grain size, poor compound morphology and excessive hydrogen content. Summary of the Invention

[0006] The present invention provides an aluminum alloy slab and a preparation method thereof, an aluminum alloy plate and a preparation method thereof, so as to solve the problem of ring-shaped segregation in the cross section of large-sized aluminum alloy ingots in the prior art.

[0007] To achieve the above-mentioned object, according to one aspect of the present invention, there is provided an aluminum alloy slab, wherein the composition of the aluminum alloy slab comprises, by mass percentage, Mg content of 4.30%-5.20%, Mn content of 0.40%-0.60%, La content of 0.05%-0.15%, Si content ≤0.25%, Zn content ≤0.25%, Cr content ≤0.20%, Ti content ≤0.15%, Fe content ≤0.50%, the total amount of unavoidable impurities ≤0.15%, and the balance being Al; at 1 / 4 of the thickness of the aluminum alloy slab, the average grain size is ≤90 μm, the maximum size of intermetallic compounds is ≤60 μm, and the average size of intermetallic compounds is ≤15 μm.

[0008] Furthermore, the width of the aluminum alloy slab is ≥1000 mm;

[0009] And / or, the solid hydrogen content of the aluminum alloy slab is ≤0.12 ug / g.

[0010] Furthermore, the aluminum alloy slab satisfies at least one of the following conditions:

[0011] (1) The average grain size of the aluminum alloy slab at 1 / 4 thickness is 70-90 μm;

[0012] (2) The maximum size of the intermetallic compound at 1 / 4 thickness of the aluminum alloy slab is 40-60 μm;

[0013] (3) The average size of the intermetallic compounds at 1 / 4 thickness of the aluminum alloy slab is 5 to 15 μm;

[0014] (4) The solid hydrogen content of the aluminum alloy slab is 0.07-0.12 ug / g.

[0015] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided a method for preparing any one of the above-mentioned aluminum alloy slabs, the preparation method comprising the following steps: step S1, batching and smelting the aluminum alloy slab according to the composition of the aluminum alloy slab to obtain an aluminum alloy melt; step S2, purifying the aluminum alloy melt to obtain a purified aluminum alloy melt; the purification treatment comprises: sequentially subjecting the aluminum alloy melt to furnace bottom degassing treatment, online double degassing treatment and two-stage filtration treatment; step S3, diverting the purified aluminum alloy melt through a diverter bag, performing semi-continuous casting, and obtaining an aluminum alloy cast ingot; step S4, uniformly sintering the aluminum alloy cast ingot chemical treatment to obtain the aluminum alloy slab; wherein, the width of the aluminum alloy slab is recorded as W0, the thickness of the aluminum alloy slab is recorded as T0, and T0≤W0, the width of the diverter bag is recorded as W1, and the thickness of the diverter bag is recorded as T1; when 1000mm≤W0<1500mm, W1 is 390mm~410mm, and T1 is 125mm~135mm; when 1500mm≤W0<2000mm, W1 is 540mm~560mm, and T1 is 135mm~145mm; when W0≥2000mm, W1 is 680~720mm, and T1 is 145mm~155mm.

[0016] Furthermore, the diversion bag satisfies at least one of the following conditions:

[0017] (1) When 1000 mm ≤ W0 < 1500 mm and 200 mm ≤ T0 < 1500 mm, W1 is 390 mm to 410 mm, and T1 is 125 mm to 135 mm;

[0018] (2) When 1500 mm ≤ W0 < 2000 mm and 600 mm ≤ T0 < 2000 mm, W1 is 540 mm to 560 mm, and T1 is 135 mm to 145 mm;

[0019] (3) When 2000 mm ≤ W0 ≤ 3000 mm and 800 mm ≤ T0 ≤ 3000 mm, W1 is 680 to 720 mm, and T1 is 145 to 155 mm.

[0020] Furthermore, the diversion bag satisfies at least one of the following conditions:

[0021] (1) The material of the diversion bag is high silica fiber;

[0022] (2) The material of the diversion bag is high-silica fiber, and the content of silicon oxide in the high-silica fiber is 95% to 98%;

[0023] (3) The continuous heat-resistant temperature of the diversion bag is greater than 1000°C;

[0024] (4) The thickness of the diversion bag material is 0.40mm~0.48mm;

[0025] (5) The diversion bag is a rectangular trough structure;

[0026] (6) The aluminum liquid permeability of the diversion bag is ≤0.2%.

[0027] Furthermore, the diversion bag satisfies at least one of the following conditions:

[0028] (1) Two circular bottom aluminum outlets are symmetrically provided on the bottom surface of the diversion bag;

[0029] (2) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the diversion bag, and the material of the bottom aluminum outlet is a high-silica fiber interwoven mesh with a mesh size of 8 to 10;

[0030] (3) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the diversion bag. The material of the bottom aluminum outlet is a high-silica fiber interwoven mesh with a thickness of 0.59mm~0.71mm;

[0031] (4) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the diversion bag. When 1000mm≤W0<2000mm, the diameter of the bottom aluminum outlet is 54mm~56mm;

[0032] (5) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the diversion bag. When 1000mm≤W0<2000mm and T0≤1000mm, the diameter of the bottom aluminum outlet is 54mm~56mm;

[0033] (6) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the diversion bag. When W0 ≥ 2000 mm, the diameter of the bottom aluminum outlet is 59 mm to 61 mm;

[0034] (7) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the diversion bag. When W0 ≥ 2000 mm and T0 ≥ 1000 mm, the diameter of the bottom aluminum outlet is 59 mm to 61 mm;

[0035] (8) Two circular bottom aluminum outlets are symmetrically provided on the bottom surface of the diversion bag, and the centers of the bottom aluminum outlets are located on the width center line of the diversion bag;

[0036] (9) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the diverter bag. The center of the bottom aluminum outlet is located on the width center line of the diverter bag. The distance between the center of the bottom aluminum outlet and the symmetry center of the bottom surface of the diverter bag is (0.25~0.35)×W1.

[0037] Furthermore, the diversion bag satisfies at least one of the following conditions:

[0038] (1) A rectangular small aluminum outlet is provided on two opposite small side surfaces of the diversion bag;

[0039] (2) A rectangular small aluminum outlet is provided on two opposite small side surfaces of the diversion bag, the mesh number of the small aluminum outlet is 8 to 10, and the thickness of the material of the small aluminum outlet is 0.59 mm to 0.71 mm;

[0040] (3) Two small side surfaces of the diversion bag are symmetrically provided with rectangular small aluminum outlets, the width of the small aluminum outlets is T1, and the height is 35-45 mm;

[0041] (4) When W0≥2000mm or T0≥1000mm, two large rectangular aluminum outlets are respectively provided on the two opposite large sides of the diversion bag;

[0042] (5) When W0≥2000mm or T0≥1000mm, two rectangular large aluminum outlets are respectively provided on the two opposite large sides of the diversion bag, the mesh number of the large aluminum outlet is 8~10 mesh, and the thickness of the material of the large aluminum outlet is 0.59mm~0.71mm;

[0043] (6) When W0≥2000mm or T0≥1000mm, two rectangular large aluminum outlets are respectively provided on the two opposite large side surfaces of the diversion bag. The two large aluminum outlets on the same side surface are symmetrically arranged relative to the vertical center line of the large side surface. The distance between the large aluminum outlet and the vertical center line of the large side surface is (0.1~0.12)W1.

[0044] (7) When W0≥2000mm or T0≥1000mm, two large rectangular aluminum outlets are respectively provided on the two opposite large side surfaces of the diversion bag, and the size of the large aluminum outlet is (0.15~0.25)W1×(35~45)mm.

[0045] Furthermore, the smelting temperature is 720-750°C;

[0046] and / or, during the smelting process, adding Mg when the temperature reaches 735-745°C;

[0047] And / or, in step S3, the speed of the semi-continuous casting is 15-35 mm / min, the temperature of the semi-continuous casting is 680-710°C, and the cooling water flow rate during the semi-continuous casting is 40-80 m 3 / h;

[0048] And / or, in step S4, the homogenization treatment includes primary homogenization and secondary homogenization performed sequentially, the temperature of the primary homogenization is 380-400° C., and the holding time is 6-8 hours; the temperature of the secondary homogenization is 460-480° C., and the holding time is 20-25 hours;

[0049] And / or, in step S4, the heating rate of the primary homogenization treatment is 100-250°C / h, and the heating rate of the secondary homogenization treatment is 50-100°C / h.

[0050] Furthermore, the furnace bottom degassing treatment includes: refining for 40 to 50 minutes through a furnace bottom degassing device;

[0051] The online double degassing treatment is carried out by an online double degassing device, wherein the rotor speed is 230~250r / min, the Ar gas flow rate is 4.0~4.5m 3 / h, Cl2 gas flow rate 0.04~0.06 m 3 / h;

[0052] The double-stage filtration process includes sequentially using a 30 ppi filter plate and a 50 ppi filter plate for filtration.

[0053] According to another aspect of the present application, a method for preparing an aluminum alloy plate is provided, which comprises the following steps: step A1, sawing an aluminum alloy ingot to obtain aluminum alloy slices, wherein the aluminum alloy ingot is any one of the above-mentioned aluminum alloy slabs or an aluminum alloy slab prepared by any one of the methods for preparing aluminum alloy slabs; step A2, anodizing the aluminum alloy slices, wherein the anodizing treatment comprises: degreasing, water washing, alkali washing, neutralization, oxidation and sealing treatment.

[0054] Furthermore, during the alkali washing, the concentration of the alkali solution is 80-100 g / L, and the alkali washing time is 1-2 min;

[0055] And / or, during the neutralization process, the neutralizing solution used is a nitric acid solution with a mass concentration of 18% to 22%, and the neutralization time is 5 to 8 minutes;

[0056] And / or, during the oxidation, the oxidizing agent used is a sulfuric acid solution with a mass concentration of 15% to 20%;

[0057] And / or, the water temperature of the sealing treatment is 70-80° C., and the time is 5-8 minutes.

[0058] According to another aspect of the present application, an aluminum alloy plate is provided, which is prepared by any of the above-mentioned methods for preparing aluminum alloy plates.

[0059] The technical solution of the present invention controls the contents of elements such as Mg, Mn, La, Si, Zn, and Cr in an aluminum alloy slab, resulting in a smaller average grain size at 1 / 4 the thickness of the aluminum alloy slab, smaller intermetallic compound sizes, a uniform alloy composition, and no ring segregation in the cross-section of the aluminum alloy slab. This aluminum alloy slab exhibits excellent mechanical properties and machining resistance, and when used in the processing of aluminum alloy plate materials, it achieves high quality and yield, effectively reducing or even preventing forging cracking and surface color differences in anodized products. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0061] Figure 1 A schematic structural diagram of a device for preparing an aluminum alloy slab provided by an embodiment of the present invention is shown;

[0062] Figure 2 An isometric view of a diversion bag provided by an embodiment of the present invention is shown;

[0063] Figure 3 Shown Figure 2 A top view of the diversion bag in FIG.

[0064] Figure 4 Shown Figure 3 An enlarged view of the diversion bag at position A;

[0065] Figure 5 Shown Figure 2 A side view of the shunt bag in FIG.

[0066] Figure 6 Shown Figure 2 A front view of the shunt bag in FIG.

[0067] Figure 7 Shown Figure 6 An enlarged view of the diversion bag at position B;

[0068] Figure 8 A cross-sectional photograph of the aluminum alloy slab prepared in Example 1 is shown (without ring segregation);

[0069] Figure 9 A cross-sectional photograph of the aluminum alloy slab prepared in Comparative Example 1 (with ring-shaped segregation) is shown;

[0070] Figure 10 shows a metallographic photograph of the aluminum alloy slab prepared in Example 1;

[0071] Figure 11Shows a metallographic photograph of the coating of the aluminum alloy slab prepared in Example 1;

[0072] Figure 12 Shown is a metallographic photograph of the aluminum alloy slab prepared in Comparative Example 1;

[0073] Figure 13 The metallographic photograph of the coating of the aluminum alloy slab prepared in Comparative Example 1 is shown.

[0074] Among them, the above drawings include the following figure marks: 10, diverter bag; 11, small aluminum outlet; 12, large aluminum outlet; 13, bottom aluminum outlet; 20, crystallizer; 40, ingot guide head. DETAILED DESCRIPTION

[0075] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0076] As analyzed in the background of this application, the prior art has the problem of ring-shaped segregation in the cross section of large-sized aluminum alloy ingots. To solve this problem, this application provides an aluminum alloy slab and a method for preparing the same, as well as an aluminum alloy plate and a method for preparing the same.

[0077] According to a typical embodiment of the present application, an aluminum alloy slab is provided, wherein the composition of the aluminum alloy slab includes, by mass percentage, Mg content of 4.30%-5.20%, Mn content of 0.40%-0.60%, La content of 0.05%-0.15%, Si content ≤0.25%, Zn content ≤0.25%, Cr content ≤0.20%, Ti content ≤0.15%, Fe content ≤0.50%, the total amount of unavoidable impurities ≤0.15%, and the balance being Al; at 1 / 4 thickness of the aluminum alloy slab, the average grain size is ≤90 μm, the maximum size of intermetallic compounds is ≤60 μm, and the average size of intermetallic compounds is ≤15 μm.

[0078] The aluminum alloy slab of the present application, by controlling the contents of elements such as Mg, Mn, La, Si, Zn, and Cr, exhibits a small average grain size at 1 / 4 the thickness of the aluminum alloy slab, small intermetallic compound size, uniform alloy composition, and no ring segregation in the cross-section of the aluminum alloy slab. This aluminum alloy slab exhibits excellent mechanical properties and processing resistance. When used in the processing of aluminum alloy plate materials, the ingot achieves high quality and yield, effectively reducing or even preventing forging cracking and surface color differences in anodized products.

[0079] For example, the average grain size at 1 / 4 thickness of the aluminum alloy slab can be 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm or other values ​​within the above range. Preferably, the average grain size at 1 / 4 thickness of the aluminum alloy slab is 70~90μm, which further improves the mechanical properties and processing performance of the slab.

[0080] For example, at 1 / 4 thickness of the aluminum alloy slab, the maximum size of the intermetallic compound is 20 μm, 30 μm, 40 μm, 50 μm, 6 μm or other values ​​within the above range. Preferably, the maximum size of the intermetallic compound at 1 / 4 thickness of the aluminum alloy slab is 40~60 μm, which is beneficial to further improve the ductility and weldability of the material.

[0081] For example, at 1 / 4 thickness of the aluminum alloy slab, the average size of the intermetallic compounds is 3 μm, 5 μm, 7 μm, 9 μm, 11 μm, 13 μm, 15 μm or any value within the above range. Preferably, the average size of the intermetallic compounds at 1 / 4 thickness of the aluminum alloy slab is 5~15 μm, which further improves the fatigue strength and fracture toughness of the material.

[0082] In some embodiments of the present application, the width of the aluminum alloy slab is ≥1000 mm. Since large-sized 5083 aluminum alloy ingots have severe ring segregation, the present application controls the grain size and the size of the intermetallic compounds at 1 / 4 of the thickness of the aluminum alloy slab to make the alloy composition uniform on the cross section of the large-sized slab, especially the slab with a width ≥1000 mm, without ring segregation.

[0083] In some embodiments of the present application, the aluminum alloy slab has a solid hydrogen content of 0.12 μg / g or less. This lower hydrogen content improves the material's formability and reduces the risk of internal cracks, making it an ideal raw material for large-scale sheet materials. This material is widely used in shipbuilding, rail vehicle hulls, and other fields, meeting these industries' requirements for dimensional stability and low hydrogen embrittlement. Preferably, the aluminum alloy slab has a solid hydrogen content of 0.07 to 0.12 μg / g, which not only provides more stable mechanical properties but also offers a better balance between performance and processing costs.

[0084] According to another typical embodiment of the present application, a method for preparing an aluminum alloy slab is provided, the method comprising the following steps: Step S1, batching and smelting the aluminum alloy slab according to the composition of the aluminum alloy slab to obtain an aluminum alloy melt; the composition of the aluminum alloy slab comprises: Mg content 4.30%-5.20%, Mn content 0.40%-0.60%, La content 0.05%-0.15%, Si content ≤0.25%, Zn content ≤0.25%, Cr content ≤0.20%, and Ti content ≤0.15%. , Fe content ≤ 0.50%, the total amount of unavoidable impurities ≤ 0.15%, and the balance is Al; step S2, purifying the aluminum alloy melt to obtain a purified aluminum alloy melt; the purification treatment comprises: sequentially performing furnace bottom degassing treatment, online double degassing treatment and double-stage filtration treatment on the aluminum alloy melt; step S3, diverting the purified aluminum alloy melt through a diverter bag, performing semi-continuous casting, and obtaining an aluminum alloy cast ingot; step S4, homogenizing the aluminum alloy cast ingot to obtain an aluminum alloy flat ingot; wherein, Figure 1 Or as shown in 2, the width of the aluminum alloy slab is recorded as W0, the thickness of the aluminum alloy slab is recorded as T0, and T0≤W0, the width of the diverter bag 10 is recorded as W1, and the thickness of the diverter bag 10 is recorded as T1; when 1000mm≤W0<1500mm, W1 is 390mm~410mm, and T1 is 125mm~135mm; when 1500mm≤W0<2000mm, W1 is 540mm~560mm, and T1 is 135mm~145mm; when W0≥2000mm, W1 is 680~720mm, and T1 is 145mm~155mm.

[0085] exist Figure 1 Where W0 is the width of the aluminum alloy slab, T0 is the thickness of the aluminum alloy slab, and W0 ≥ T0, H0 is the height of the aluminum alloy slab. The end of the aluminum-magnesium alloy ingot is the ingot starter 40. Figure 2 In FIG. 1 , W1 is the width of the diverter bag 10 , and T1 is the thickness of the diverter bag 10 .

[0086] This application utilizes diverter bags 10 of varying structural dimensions for aluminum alloy slabs of varying sizes to improve the flow distribution of molten aluminum within the ingot. This improves the fullness and stability of molten aluminum filling during the start-up phase of casting, ensuring complete filling in corners and the center of large surfaces. Furthermore, the application reduces the probability, intensity, and range of molten aluminum turbulence during the stable casting phase, preventing localized violent agitation of the molten aluminum and improving the uniformity of alloy composition. Furthermore, the use of adapted diverter bags 10, combined with an optimized 5083 alloy ingot elemental composition, purification treatment, and semi-continuous casting process, increases the ingot cooling rate, reduces the temperature difference between the center and edges of the ingot, refines the grains, eliminates coarse compounds (such as AIMgCrMn, AIMgMnFe, and AIMgMn), and produces uniformly sized compounds (AIMgCrMnFe). At 1 / 4 thickness of the aluminum alloy flat ingot prepared by the above preparation method, the average grain size is ≤90μm, the maximum size of the intermetallic compound is ≤60μm, and the average size of the intermetallic compound is ≤15μm, so that large-size 5083 aluminum alloy ingots with an ingot width of ≥1000mm no longer produce ring segregation defects, significantly improving the overall quality of subsequent finished parts.

[0087] In some embodiments of the present application, when 1000mm≤W0<1500mm and 200mm≤T0<1500mm, W1 is 390mm~410mm, and T1 is 125mm~135mm. When the size of the aluminum alloy slab is within the above range, using a diverter bag with W1 of 390mm~410mm and T1 of 125mm~135mm can further reduce the probability, intensity and range of action of aluminum liquid turbulence, thereby making the structure of the aluminum alloy slab more uniform and obtaining better overall performance.

[0088] In some embodiments of the present application, when 1500mm≤W0<2000mm and 600mm≤T0<2000mm, W1 is 540mm~560mm, and T1 is 135mm~145mm. When the size of the aluminum alloy slab is within the above range, using a diverter bag with W1 of 540mm~560mm and T1 of 135mm~145mm can further reduce the probability, intensity and range of action of aluminum liquid turbulence, thereby making the structure of the aluminum alloy slab more uniform and obtaining better overall performance.

[0089] In some embodiments of the present application, when 2000mm≤W0≤3000mm and 800mm≤T0≤3000mm, W1 is 680~720mm, and T1 is 145mm~155mm. When the size of the aluminum alloy slab is within the above range, using a diverter bag with W1 of 680~720mm and T1 of 145mm~155mm can further reduce the probability, intensity and range of action of aluminum liquid turbulence, thereby making the structure of the aluminum alloy slab more uniform and obtaining better overall performance.

[0090] In some embodiments of the present application, the material of the diverter bag 10 is high-silica fiber, that is, high-purity amorphous continuous silicon oxide fiber. The silicon oxide content in the high-silica fiber is 95% to 98%, and the heat resistance is excellent. The aluminum outlet of the diverter bag 10 is a high-silica fiber interwoven mesh, and the rest of the bag is a high-silica fiber cloth. In some embodiments of the present application, the continuous heat resistance temperature of the diverter bag 10 is greater than 1000°C.

[0091] In some embodiments of the present application, the thickness of the material of the diversion bag 10 is 0.40 mm to 0.48 mm.

[0092] In some embodiments of the present application, the diversion bag 10 is a rectangular parallelepiped trough structure.

[0093] In some embodiments of the present application, the aluminum liquid permeability of the diverter bag 10 is ≤0.2%, where the permeability represents the ratio of the volume flow rate of the fluid through a unit area of ​​the medium per unit time under gravity drive to the total volume of the medium.

[0094] In some embodiments of the present application, Figure 3 、 4 As shown, two circular bottom aluminum outlets 13 are symmetrically arranged on the bottom surface of the diverter bag 10. The circular aluminum outlets are arranged at the bottom of the diverter, and are symmetrically arranged, which is beneficial to reducing the probability of turbulence during the flow of the aluminum-magnesium alloy melt in the crystallizer 20 and the liquid cavity, and avoiding severe disturbance of the aluminum liquid locally.

[0095] In some embodiments of the present application, the material of the above-mentioned bottom aluminum outlet 13 is a high-silica fiber interwoven mesh with a mesh size of 8~10 meshes, and the flow rate is relatively uniform; preferably, the thickness of the high-silica fiber interwoven mesh of the bottom aluminum outlet is 0.59mm~0.71mm, which is more durable.

[0096] In some embodiments of the present application, when 1000mm ≤ W0 < 2000mm, the diameter of the bottom aluminum tap is 54mm-56mm. A bottom aluminum tap of this size, when used to prepare aluminum alloy slabs of the aforementioned size, can reduce the amount of turbulence in the melt during the casting process and reduce the scope of turbulence, avoiding the 1 / 3 to 1 / 4 thickness region where composition segregation and porosity are common. In particular, when 1000mm ≤ W0 < 2000mm and T0 ≤ 1000mm, a bottom aluminum tap diameter of 54mm-56mm can better regulate the flow state of the alloy melt during the casting process, reduce the amount of turbulence and the scope of turbulence, and improve the overall quality of the ingot.

[0097] In some embodiments of the present application, when W0 ≥ 2000 mm, the diameter of the bottom aluminum tap is 59 mm to 61 mm. A bottom aluminum tap of this size, when used to prepare aluminum alloy slabs of the aforementioned sizes, can minimize turbulence during the casting process, narrowing the scope of turbulence and avoiding the 1 / 3 to 1 / 4 thickness region where composition segregation and porosity are common. In particular, when W0 ≥ 2000 mm and T0 ≥ 1000 mm, a bottom aluminum tap diameter of 59 mm to 61 mm can better regulate the flow state of the alloy melt during casting of this size, reduce the amount and scope of turbulence, and improve the overall quality of the ingot.

[0098] In some embodiments of the present application, the center of the bottom aluminum outlet is located on the width center line of the diverter bag 10; preferably, the distance between the center of the bottom aluminum outlet and the symmetry center of the bottom surface of the diverter bag 10 is (0.25~0.35)×W1, which can make the melt flow of large-size ingots more stable and reduce the probability, intensity and range of turbulence during the flow of aluminum liquid in the crystallizer and liquid cavity.

[0099] In some embodiments of the present application, Figure 2 、 Figure 5 As shown, two small side surfaces at opposite positions of the diverter bag 10 are respectively provided with rectangular small aluminum outlets 11. This design ensures the smooth flow of the melt when entering the mold, reduces turbulence, and is conducive to the formation of a uniform and dense microstructure. It is suitable for the manufacture of aluminum alloy plates that require high flatness, such as high-end building decoration materials, high-end furniture panels, etc. The material of the small aluminum outlet 11 can also be a high-silica fiber interwoven mesh. Preferably, the mesh number of the small aluminum outlet is 8 to 10 meshes, and the thickness is 0.59 mm to 0.71 mm. Preferably, the small aluminum outlets 11 on the two small side surfaces at opposite positions of the diverter bag 10 are symmetrically arranged, and the width of the small aluminum outlet is T1, which is the same as the width of the diverter bag 10, and the height is 35 to 45 mm.

[0100] In some embodiments of the present application, Figure 2 、 6As shown in 7, when W0≥2000mm or T0≥1000mm, two large rectangular aluminum outlets 12 are respectively provided on the two opposite large side surfaces of the diverter bag 10. When the width or thickness of the flat ingot is large, the large aluminum outlet 12 is provided on the large side surface of the diverter bag 10, which helps to promote the smooth flow of the melt when it enters the mold and form a dense microstructure. The material of the large aluminum outlet 12 can also be a high-silica fiber interwoven mesh. Preferably, the mesh number of the large aluminum outlet is 8~10 meshes and the thickness is 0.59mm~0.71mm. Preferably, the two large aluminum outlets on the same side are symmetrically arranged relative to the vertical center line of the large side surface, and the large aluminum outlet is (0.1~0.12) W1 away from the vertical center line of the large side surface, which is conducive to further promoting the smooth flow of the melt and improving the performance of the ingot. Preferably, the size of the large aluminum outlet is (0.15~0.25)W1×(35~45)mm, wherein the longer side is the width of the large aluminum outlet, i.e. (0.15~0.25)W1, and the shorter side is the height of the large aluminum outlet, i.e. (35~45)mm.

[0101] The influence of the process parameters in each step of the preparation method on the effect is described in detail below with reference to the embodiments.

[0102] In some embodiments of the present application, the melting temperature is 720-750°C; during the melting process, Mg is added when the temperature reaches 735-745°C; melting within this temperature range can effectively dissolve alloy elements and promote grain refinement, while avoiding excessive evaporation of alloy components at high temperatures and maintaining the chemical balance of the alloy, which is suitable for manufacturing aluminum alloy products requiring high toughness and good formability.

[0103] In some embodiments of the present application, the purification treatment includes: subjecting the aluminum alloy melt to furnace bottom degassing treatment, online double degassing treatment and double-stage filtration treatment in sequence, which can effectively reduce the hydrogen content of the melt and improve the purity of the melt. Among them, the furnace bottom degassing treatment includes: refining for 40 to 50 minutes through the furnace bottom degassing device. The online double degassing treatment is carried out through the online double degassing device, wherein the rotor speed is 230 to 250 r / min, and the Ar gas flow rate is 4.0 to 4.5 m 3 / h, Cl2 gas flow rate 0.04~0.06 m 3 / h; the dual-stage filtration process includes sequential filtration using a 30ppi filter plate and a 50ppi filter plate. By combining the above purification process with the diversion method and semi-continuous casting process of the present application, the quality of the ingot can be significantly improved, and its processing performance and mechanical properties can be enhanced.

[0104] In some embodiments of the present application, in the above step S3, the speed of semi-continuous casting is 15-35 mm / min, the temperature of semi-continuous casting is 680-710°C, and the cooling water flow rate during semi-continuous casting is 40-80 m3 / h.

[0105] In some embodiments of the present application, in step S4, the homogenization treatment includes primary homogenization and secondary homogenization performed in sequence, the temperature of the primary homogenization is 380~400℃, and the holding time is 6~8h; the temperature of the secondary homogenization is 460~480℃, and the holding time is 20~25h. The above-mentioned semi-continuous casting process, adapted to the diverter bag 10, can increase the cooling rate of the ingot, reduce the temperature difference between the center and the edge of the ingot, refine the grains, and eliminate coarse compounds. Preferably, the heating rate of the primary homogenization treatment is 100~250℃ / h, and the heating rate of the secondary homogenization treatment is 50~100℃ / h.

[0106] In some embodiments of the present application, the homogenization treatment of step S4 includes: starting heating the aluminum alloy cast ingot at room temperature, with a heating rate of 100~250℃ / h, a first-level homogenization temperature of 380~400℃, a holding time of 6~8h, a second-level homogenization temperature of 460~480℃, a holding time of 20~25h, air cooling to 240~260℃, and then air cooling to room temperature.

[0107] According to another typical embodiment of the present application, a method for preparing an aluminum alloy plate is provided, and the preparation method includes the following steps: step A1, sawing the aluminum alloy ingot to obtain aluminum alloy slices, the aluminum alloy ingot is any one of the above-mentioned aluminum alloy flat ingots or an aluminum alloy flat ingot prepared by any of the above-mentioned aluminum alloy flat ingot preparation methods; step A2, anodizing the aluminum alloy slices, and the anodizing treatment includes: degreasing, water washing, alkali washing, neutralization, oxidation and sealing treatment.

[0108] Because the aluminum alloy slab has a smaller average grain size and smaller intermetallic compound size at 1 / 4 of its thickness, its alloy composition is uniform, and its cross-section is free of ring segregation, sawing and anodizing it can produce aluminum alloy sheets with a higher yield rate and higher mechanical strength and surface quality.

[0109] The thickness of the aluminum alloy slice can be determined according to specific needs or processes, and this application has no limitation on this.

[0110] In some embodiments of the present application, degreasing includes soaking in a 30~36g / L neutral degreasing powder aqueous solution. Preferably, the neutral degreasing powder aqueous solution contains sodium alkylbenzene sulfonate, dextran, polysaccharide and sodium tripolyphosphate in a mass ratio of 5:2:2:1; preferably, the soaking time is 3~10min and the temperature is 50±5°C.

[0111] In some embodiments of the present application, during alkali washing, the concentration of the alkali solution is 80-100 g / L, and the alkali washing time is 1-2 min.

[0112] In some embodiments of the present application, during the neutralization process, the neutralizing solution used is a nitric acid solution with a mass concentration of 18% to 22%, and the neutralization time is 5 to 8 minutes.

[0113] In some embodiments of the present application, during oxidation, the oxidizing agent used is a sulfuric acid solution with a mass concentration of 15% to 20%.

[0114] In some embodiments of the present application, the water temperature of the sealing treatment is 70-80° C., and the time is 5-8 minutes.

[0115] In some embodiments of the present application, the anodizing process is as follows: degreasing (30-36 g / L neutral degreasing powder aqueous solution, 50 ± 5°C, soaking for 5 min) → water washing → alkaline washing (80-100 g / L, 1-2 min) → water washing → neutralization (HNO3, H2O volume ratio of 3:7, 5-8 min) → water washing → oxidation (H2SO4, H2O mass ratio of 1:4, 25-30 min) → sealing (water temperature 70-80°C, 5-8 min). Using this process for anodizing, the above-mentioned aluminum alloy material has no color difference, which can significantly improve the yield of semiconductor products.

[0116] According to another typical embodiment of the present application, an aluminum alloy plate is provided, produced by the above-described preparation method. Due to the use of the above-described aluminum alloy slab as raw material and the above-described preparation process, the aluminum alloy plate produced in the present application exhibits excellent mechanical properties and surface quality, and is widely applicable to the production of ships, automobiles, aircraft welded parts, subway and light rail vehicles, pressure vessels requiring strict fire protection (such as liquid tankers, refrigerated trucks, and refrigerated containers), refrigeration equipment, television towers, drilling equipment, transportation equipment, missile parts, armor, and the like.

[0117] The present application is further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0118] The material of the diverter bags used in the embodiments and comparative examples of the present application are all high-silica fiber with a silicon oxide content of 95-98% and a continuous heat-resistant temperature of >1000°C; among them, the material of each aluminum outlet is a high-silica fiber interwoven mesh with a mesh size of approximately 8-10 meshes, a thickness of 0.65±0.06mm, and a weight of 295g / ㎡; the remaining parts are high-silica fiber cloth with a thickness of 0.44±0.04mm, a weight of 420g / ㎡, and an aluminum liquid permeability of ≤0.2%.

[0119] Example 1

[0120] (1) The aluminum alloy composition is prepared as follows: in percentage by mass, Mg: 4.30%, Mn: 0.40%, Si: 0.1%, Zn: 0.05%, Cr: 0.10%, Ti: 0.10%, Fe: 0.10%, the sum of unavoidable impurities ≤ 0.15%, and the balance is Al; the components except Mg are mixed and smelted at a temperature of 750-770°C. After all the components are melted, pure Mg is added when the melt is cooled to 740°C to obtain an aluminum alloy melt.

[0121] (2) The aluminum alloy melt is purified. Specifically, the aluminum alloy melt obtained by smelting is refined using a furnace bottom degassing system for 40 minutes; then degassing is performed using an online double degassing device, with the rotor speed set at 230 rpm and the Ar gas flow rate at 4.0 m 3 / h, Cl2 gas flow rate is 0.04m 3 / h; the degassed aluminum alloy melt is filtered using 30ppi and 50ppi filter plates. The aluminum-magnesium alloy melt after double-stage filtration is tested online for hydrogen using the ABB ALSCAN hydrogen analyzer, with a hydrogen content of 0.09ml / 100g Al.

[0122] (3) The aluminum alloy melt after the above purification treatment is diverted through a diversion bag. The width W1 of the diversion bag is 400mm, the thickness T1 is 130mm, and the height H1 is 125mm. The bottom aluminum outlet is circular with a diameter of 55mm. The center of the bottom aluminum outlet is located on the width center line of the diversion bag and the distance from the symmetry center of the bottom of the diversion bag is 120mm; the small aluminum outlet on the small side is rectangular with a size of 130mm×40mm (height), and there is no aluminum outlet on the large side. The diverted alloy melt is semi-continuously cast. The semi-continuous casting speed is 35mm / min, the casting temperature is 710℃, and the cooling water flow rate during semi-continuous casting is 40m 3 / h, and obtain aluminum alloy cast ingot with size of 1320 (W0) × 400 (T0).

[0123] (4) The aluminum alloy cast ingot is subjected to homogenization annealing treatment. The ingot is heated at room temperature at a heating rate of 250°C / h, heated to 400°C and kept at this temperature for 6 hours for primary homogenization; heated to 480°C at a heating rate of 100°C / h and kept at this temperature for 20 hours for secondary homogenization; then air-cooled to 250°C and then air-cooled to room temperature to obtain an aluminum alloy flat ingot.

[0124] After the aluminum alloy slab prepared in this embodiment is sawn, the cross section of the slice is as follows: Figure 8 As shown. And Figure 10 and 11The metallographic photographs of the aluminum alloy slab prepared in this embodiment and the metallographic photographs of the coating are shown respectively.

[0125] The aluminum alloy slab prepared in this embodiment was tested for component segregation according to the following method: the aluminum alloy slab was sawed, cross-sectional slices were taken, and the instrument was calibrated with a standard sample using direct reading spectroscopy to quickly detect the main element content of the bulk sample. As the main element of the 5083 aluminum alloy, the distribution pattern of the solute element Mg in the cross section along the thickness direction is central negative segregation, that is, the Mg content in the central area is low, resulting in central negative segregation; at one-quarter the thickness of the cross section, the Mg element shows positive segregation, that is, the Mg content in this area is high. In the aluminum alloy slab of this embodiment, the Mg element shows negative segregation in the middle along the thickness direction, and shows positive segregation at one-quarter the thickness. The maximum negative segregation degree is 0.46, and the maximum positive segregation degree is 0.73.

[0126] Example 2

[0127] (1) The aluminum alloy composition is prepared as follows: in percentage by mass, Mg: 4.75%, Mn: 0.50%, Si: 0.17%, Zn: 0.12%, Cr: 0.15%, Ti: 0.13%, Fe: 0.20%, the total of unavoidable impurities is ≤ 0.15%, and the balance is Al; the components except Mg are mixed and smelted at a temperature of 750-770°C. After all the components are melted, pure Mg is added when the melt is cooled to 740°C to obtain an aluminum alloy melt.

[0128] (2) The aluminum alloy melt is purified. Specifically, the aluminum alloy melt obtained by smelting is refined using a furnace bottom degassing system with a time setting of 45 min; then degassing is performed using an online double degassing device with a rotor speed set at 240 rpm and an Ar gas flow rate of 4.3 m 3 / h, Cl2 gas flow rate is 0.05m 3 / h; the degassed aluminum alloy melt was filtered using 30ppi and 50ppi filter plates. The aluminum-magnesium alloy melt after double-stage filtration was tested online for hydrogen content using the ABB ALSCAN hydrogen analyzer, with a hydrogen content of 0.08 ml / 100g Al.

[0129] (3) The aluminum alloy melt after the above purification treatment is diverted through a diversion bag. The width W1 of the diversion bag is 550mm, the thickness T1 is 140mm, and the height H1 is 125mm. The bottom aluminum outlet is circular with a diameter of 60mm. The center of the bottom aluminum outlet is located on the width center line of the diversion bag and the distance from the symmetry center of the bottom of the diversion bag is 165mm. The small aluminum outlet on the small side is rectangular with a size of 140mm×40mm (height). There are two large aluminum outlets on each large side. The size of the large aluminum outlet is 110mm×40mm. The two large aluminum outlets on the same side are symmetrically arranged relative to the vertical center line of the large side. The large aluminum outlet is 60.5mm away from the vertical center line of the large side. The diverted alloy melt is semi-continuously cast. The semi-continuous casting speed is 27 mm / min, the casting temperature is 710℃, and the cooling water flow rate during semi-continuous casting is 55m 3 / h, and obtain aluminum alloy cast ingot with a size of 1550 (W0) × 1050 (T0).

[0130] (4) The aluminum alloy cast ingot is subjected to homogenization annealing treatment. The ingot is heated at room temperature at a heating rate of 170°C / h, and is heated to 390°C and kept at this temperature for 7 hours for the first homogenization. The ingot is heated to 470°C at a heating rate of 75°C / h and kept at this temperature for 23 hours for the second homogenization. The ingot is then air-cooled to 250°C and then air-cooled to room temperature to obtain an aluminum alloy flat ingot.

[0131] Example 3

[0132] (1) The aluminum alloy composition is prepared as follows: in percentage by mass, Mg: 5.2%, Mn: 0.60%, Si: 0.24%, Zn: 0.20%, Cr: 0.20%, Ti: 0.15%, Fe: 0.30%, the total of unavoidable impurities is ≤ 0.15%, and the balance is Al; the components except Mg are mixed and smelted at a temperature of 750-770°C. After all the components are melted, pure Mg is added when the melt is cooled to 740°C to obtain an aluminum alloy melt.

[0133] (2) The aluminum alloy melt is purified. Specifically, the aluminum alloy melt obtained by smelting is refined using a furnace bottom degassing system for 50 min; then degassing is performed using an online double degassing device, with the rotor speed set at 250 rpm and the Ar gas flow rate at 4.5 m 3 / h, Cl2 gas flow rate is 0.06m 3 / h; the degassed aluminum alloy melt is filtered using 30ppi and 50ppi filter plates. The aluminum-magnesium alloy melt after double-stage filtration is tested online for hydrogen using the ABB ALSCAN hydrogen analyzer, with a hydrogen content of 0.07ml / 100g Al.

[0134] (3) The aluminum alloy melt after the above purification treatment is diverted through a diversion bag. The width W1 of the diversion bag is 700mm, the thickness T1 is 150mm, and the height H1 is 125mm. The bottom aluminum outlet is circular with a diameter of 60mm. The center of the bottom aluminum outlet is located on the width center line of the diversion bag and is 210mm away from the symmetry center of the bottom surface of the diversion bag. The small aluminum outlet on the small side is rectangular with a size of 150mm×40mm (height). There are two large aluminum outlets on each large side. The size of the large aluminum outlet is 140mm×40mm. The two large aluminum outlets on the same side are symmetrically arranged relative to the vertical center line of the large side. The large aluminum outlet is 77mm away from the vertical center line of the large side. The diverted alloy melt is semi-continuously cast. The semi-continuous casting speed is 20 mm / min, the casting temperature is 710℃, and the cooling water flow rate during semi-continuous casting is 70m 3 / h, and obtain aluminum alloy cast ingot with a size of 2200 (W0) × 900 (T0).

[0135] (4) The aluminum alloy cast ingot is subjected to homogenization annealing treatment. The ingot is heated at room temperature at a heating rate of 100°C / h, and is heated to 380°C and kept at this temperature for 8 hours for the first homogenization. The ingot is heated to 460°C at a heating rate of 50°C / h and kept at this temperature for 25 hours for the second homogenization. The ingot is then air-cooled to 250°C and then air-cooled to room temperature to obtain an aluminum alloy flat ingot.

[0136] Example 4

[0137] The difference from Example 1 is that in step (4), the casting speed during semi-continuous casting is 15 mm / min and the cooling water flow rate is 80 m 3 / h.

[0138] Example 5

[0139] The difference from Example 1 is that in step (4), the casting speed during semi-continuous casting is 680°C, the cooling water flow rate is 40m 3 / h.

[0140] Example 6

[0141] The difference from Example 1 is that in step (4), the casting speed during semi-continuous casting is 25 mm / min, the casting temperature is 695°C, and the cooling water flow rate is 60 m 3 / h.

[0142] Example 7

[0143] The difference from Example 1 is that in step (4), the casting speed during semi-continuous casting is 15 mm / min, the casting temperature is 670°C, and the cooling water flow rate is 100 m 3 / h.

[0144] Example 8

[0145] The difference from Example 1 is that in step (4), the casting speed during semi-continuous casting is 730°C, the cooling water flow rate is 60m 3 / h.

[0146] Example 9

[0147] The difference from Example 1 is that in step (2), the furnace bottom degassing system is refined, and the time is set to 50 minutes.

[0148] The aluminum-magnesium alloy melt after double-stage filtration was tested for hydrogen online using the ABB hydrogen analyzer ALSCAN, and the hydrogen content was 0.08 ml / 100 g Al.

[0149] Example 10

[0150] The difference from Example 1 is that in step (2), degassing is performed by an online double degassing device, wherein the Ar gas flow rate is 4.5m 3 / h, Cl2 gas flow rate 0.06 m 3 / h.

[0151] The aluminum-magnesium alloy melt after double-stage filtration was tested for hydrogen online using the ABB hydrogen analyzer ALSCAN, and the hydrogen content was 0.08 ml / 100 g Al.

[0152] Example 11

[0153] The difference from Example 1 is that in step (2), degassing is performed by an online double degassing device, wherein the rotor speed is 250 r / min.

[0154] The aluminum-magnesium alloy melt after double-stage filtration was tested for hydrogen online using the ABB hydrogen analyzer ALSCAN, and the hydrogen content was 0.08 ml / 100 g Al.

[0155] Example 12

[0156] The difference from Example 1 is that in step (4) homogenization annealing treatment, the ingot is heated at room temperature at a heating rate of 280°C / h, heated to 400°C and kept warm for 6 hours for primary homogenization; heated to 480°C at a heating rate of 140°C / h, kept warm for 20 hours, and carried out secondary homogenization; then air-cooled to 250°C, and then air-cooled to room temperature to obtain an aluminum alloy flat ingot.

[0157] Example 13

[0158] The difference from Example 1 is that in step (4) homogenization annealing treatment, the ingot is heated at room temperature at a heating rate of 100°C / h, heated to 400°C and kept warm for 6 hours for primary homogenization; heated to 480°C at a heating rate of 50°C / h, kept warm for 20 hours, and carried out secondary homogenization; then air-cooled to 250°C, and then air-cooled to room temperature to obtain an aluminum alloy flat ingot.

[0159] Example 14

[0160] The difference from Example 1 is that in step (4) homogenization annealing treatment, the ingot is heated at room temperature at a heating rate of 250°C / h, heated to 410°C and kept warm for 6 hours, and then subjected to primary homogenization; heated to 490°C at a heating rate of 100°C / h, kept warm for 20 hours, and then subjected to secondary homogenization; then air-cooled to 250°C, and then air-cooled to room temperature to obtain an aluminum alloy flat ingot.

[0161] Example 15

[0162] The difference from Example 1 is that in step (4) homogenization annealing treatment, the ingot is heated at room temperature at a heating rate of 250°C / h, heated to 380°C and kept warm for 6 hours, and then subjected to primary homogenization; heated to 460°C at a heating rate of 100°C / h, kept warm for 20 hours, and then subjected to secondary homogenization; then air-cooled to 250°C, and then air-cooled to room temperature to obtain an aluminum alloy flat ingot.

[0163] Example 16

[0164] The difference from Example 1 is that in step (3), the diameter of the bottom aluminum outlet is 60 mm.

[0165] Comparative Example 1

[0166] The difference from Example 1 is that the diverter bag used in step (3) is different. The width W1 of the diverter bag is 330 mm, the thickness T1 is 130 mm, there is no bottom aluminum outlet and aluminum outlet on the large side, and each small side has a small rectangular aluminum outlet with a size of 130 mm × 40 mm (height).

[0167] After the aluminum alloy slab prepared in the comparative example was sawed, the cross section of the slice was as follows: Figure 9 As shown. And, Figure 12 and 13 The metallographic photographs of the aluminum alloy slab prepared in this comparative example and the metallographic photographs of the coating are shown.

[0168] The aluminum alloy slab prepared in this comparative example was subjected to a component segregation test in the same manner as in Example 1. The results were as follows: in the thickness direction, the Mg element showed negative segregation in the middle and positive segregation at one-quarter of the thickness; the maximum negative segregation degree was 0.62, and the maximum positive segregation degree was 0.91.

[0169] Comparative Example 2

[0170] The difference from Example 2 is that the diverter bag used in step (3) is different. The width W1 of the diverter bag is 330 mm, the thickness T1 is 130 mm, there is no bottom aluminum outlet and aluminum outlet on the large side, and each small side has a small rectangular aluminum outlet with a size of 130 mm × 40 mm (height).

[0171] Comparative Example 3

[0172] The difference from Example 3 is that the diverter bag used in step (3) is different. The width W1 of the diverter bag is 330 mm, the thickness T1 is 130 mm, there is no bottom aluminum outlet and aluminum outlet on the large side, and each small side has a small rectangular aluminum outlet with a size of 130 mm × 40 mm (height).

[0173] Comparative Example 4

[0174] The difference from Example 1 lies in the purification process in step (2). Specifically, the aluminum alloy melt obtained by smelting is refined using a furnace bottom degassing system for 40 min; then degassing is performed using an online degassing device, with the rotor speed set at 240 rpm and the Ar gas flow rate at 5 m 3 / h; the degassed aluminum alloy melt was filtered through a 30 ppi filter plate. The aluminum-magnesium alloy melt after double-stage filtration was tested online for hydrogen content using the ABB ALSCAN hydrogen analyzer, with a hydrogen content of 0.14 ml / 100 g Al.

[0175] Comparative Example 5

[0176] The difference from Example 1 lies in the purification process in step (2). Specifically, the aluminum alloy melt obtained by smelting is refined using a furnace bottom degassing system for 40 min; then degassing is performed using an online degassing device, with the rotor speed set at 240 rpm and the Ar gas flow rate at 5 m 3 / h; the degassed aluminum alloy melt is filtered through a 50 ppi filter plate. The aluminum-magnesium alloy melt after double-stage filtration is tested online for hydrogen content using the ABB ALSCAN hydrogen analyzer, with a hydrogen content of 0.14 ml / 100 g Al.

[0177] Comparative Example 6

[0178] The difference from Example 1 lies in the purification process in step (2). Specifically, the aluminum alloy melt obtained by smelting is refined using a furnace bottom degassing system for 40 min; then degassing is performed using an online degassing device, with the rotor speed set at 240 rpm and the Cl2 gas flow rate at 0.06 m 3 / h; the degassed aluminum alloy melt is filtered through a 50 ppi filter plate. The aluminum-magnesium alloy melt after double-stage filtration is tested online for hydrogen using the ABB ALSCAN hydrogen analyzer, with a hydrogen content of 0.13 ml / 100 g Al.

[0179] The aluminum alloy slabs were tested as follows. The test results are listed in Table 1 below. The ingot sampling locations for the average grain size test, intermetallic compound size test, solid-state hydrogen measurement, and loose agglomerate size test were all 1 / 4 of the thickness.

[0180] High-magnification microstructure examination: Sample pretreatment: grinding, polishing, etching, and anodizing; Testing standard: GB / T 3246.1-2012; Testing equipment: OLYMPUS GX51 metallographic microscope / JCS-049; Environmental conditions: 23°C.

[0181] Macroscopic examination: Sample pretreatment: grinding and etching; Testing basis: GB / T 3246.2-2012; Testing equipment: camera; Environmental conditions: 23°C.

[0182] Average grain size test: 5 metallographic coating photos at 500 times magnification were selected and processed using the image processing software Image-ProPlus. The grain size values ​​of the entire photo were counted and the average value of the 5 photos was taken.

[0183] Intermetallic compound size test: Five 500x scanned photos were selected and processed using the image processing software Image-ProPlus. The intermetallic compound size values ​​of the entire photo were counted and the average value of the five photos was taken.

[0184] Solid-state hydrogen measurement: Test basis: GB / T 14265-2017; Testing equipment: ONH836 oxygen-nitrogen-hydrogen combined tester; Environmental conditions: 22°C.

[0185] Loose agglomeration size test: 5 200x metallographic tissue photos were selected and processed using the image processing software Image-ProPlus. The loose size value of the entire photo was counted, and the values ​​of the 5 photos were averaged.

[0186] Table 1

[0187]

[0188] Application Example 1

[0189] The aluminum alloy slabs prepared in the above examples and comparative examples were processed according to the following process.

[0190] Aluminum alloy flat ingots were sawn into 20 mm thick cross-section slices. The slices were anodized. The anodizing process was as follows: degreasing (30 g / L neutral degreasing powder aqueous solution (sodium alkylbenzene sulfonate: dextran: polysaccharide: sodium tripolyphosphate = 5:2:2:1), 45°C, soaking for 5 min) → water washing → alkaline washing (80 g / L, 1 min) → water washing → neutralization (HNO₃:H₂O volume ratio of 3:7, 5 min) → water washing → oxidation (H₂SO₄:H₂O mass ratio of 1:4, 25 min) → sealing (water temperature of 70°C, 5 min).

[0191] The yield rate and appearance test results of the aluminum alloy plates prepared in the above embodiment and comparative example after the above treatment are shown in the following table. The yield rate and appearance test methods are as follows:

[0192] Yield rate: number of qualified products / total production quantity;

[0193] Appearance Inspection: According to GB / T 19822-2024 Specification for Hard Anodic Oxide Coatings on Aluminum and Aluminum Alloys, all major surfaces must be anodized, with a uniform appearance and no areas of flaking, pinholes, or powdering (burns). Visual inspection should be used for batch acceptance of appearance. Color difference indicates inconsistent appearance uniformity.

[0194] Table 2

[0195]

[0196] Application Example 2

[0197] The aluminum alloy slab prepared in Example 1 was processed in a similar manner to that of Application Example 1, except for the process parameters listed in Table 3 below.

[0198] Table 3

[0199]

[0200] The yield rate and appearance inspection results of the aluminum alloy plates of the above application examples are shown in Table 4 below.

[0201] Table 4

[0202]

[0203] As can be seen from the foregoing, the technical solution of the present invention achieves the following technical effects: The alloy slab of the present application, by controlling the contents of elements such as Mg, Mn, La, Si, Zn, and Cr, exhibits a smaller average grain size and smaller intermetallic compound size at 1 / 4 the thickness of the aluminum alloy slab, a uniform alloy composition, and no ring segregation in the cross-section of the aluminum alloy slab. This aluminum alloy slab exhibits excellent mechanical properties and processing resistance, and when used in processing aluminum alloy plate materials, the ingot achieves high quality and yield, effectively reducing or even preventing forging cracking and surface color differences in anodized products.

[0204] The above description is merely an optional embodiment of the present invention and is not intended to limit the present invention. Persons skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

[0205] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0206] Unless otherwise specified, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of this solution. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the techniques, methods and equipment should be considered as part of the specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary, rather than limiting. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0207] In the description of this scheme, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this scheme and simplifying the description. Unless otherwise stated, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this scheme; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0208] For ease of description, spatially relative terms such as "above," "above," "on the upper surface of," and "upper" may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in a drawing is inverted, a device described as "above" or "on top of" another device or structure would then be positioned as "below" or "below" the other device or structure. Thus, the exemplary term "above" can include both the "above" and "below" orientations. The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used herein should be interpreted accordingly.

[0209] In addition, it should be noted that the use of words such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this solution.

Claims

1. An aluminum alloy flat ingot, characterized in that: The composition of the aluminum alloy slab includes, by mass percentage, Mg content of 4.30%-5.20%, Mn content of 0.40%-0.60%, La content of 0.05%-0.15%, Si content ≤0.25%, Zn content ≤0.25%, Cr content ≤0.20%, Ti content ≤0.15%, Fe content ≤0.50%, the total amount of unavoidable impurities ≤0.15%, and the balance being Al; The width of the aluminum alloy slab is ≥1000 mm; At 1 / 4 of the thickness of the aluminum alloy slab, the average grain size is ≤90 μm, the maximum size of the intermetallic compound is ≤60 μm, and the average size of the intermetallic compound is ≤15 μm.

2. The aluminum alloy slab according to claim 1, characterized in that: The solid hydrogen content of the aluminum alloy slab is ≤0.12 μg / g.

3. The aluminum alloy slab according to claim 1, characterized in that: The aluminum alloy slab satisfies at least one of the following conditions: (1) The average grain size of the aluminum alloy slab at 1 / 4 thickness is 70-90 μm; (2) The maximum size of the intermetallic compound at 1 / 4 thickness of the aluminum alloy slab is 40-60 μm; (3) The average size of the intermetallic compounds at 1 / 4 thickness of the aluminum alloy slab is 5 to 15 μm; (4) The solid hydrogen content of the aluminum alloy slab is 0.07-0.12 μg / g.

4. A method for preparing an aluminum alloy slab according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step S1, preparing ingredients and smelting the aluminum alloy slab according to the composition to obtain an aluminum alloy melt; Step S2, purifying the aluminum alloy melt to obtain a purified aluminum alloy melt; the purification process includes: sequentially performing furnace bottom degassing, online double degassing, and double-stage filtration on the aluminum alloy melt; Step S3, diverting the purified aluminum alloy melt through a diverter bag and performing semi-continuous casting to obtain an aluminum alloy cast ingot; two circular bottom aluminum outlets are symmetrically provided on the bottom surface of the diverter bag, and rectangular small aluminum outlets are respectively provided on two opposite small side surfaces of the diverter bag; Step S4, homogenizing the aluminum alloy as-cast ingot to obtain the aluminum alloy slab; The width of the aluminum alloy slab is recorded as W0, the thickness of the aluminum alloy slab is recorded as T0, and T0≤W0, the width of the diverter bag is recorded as W1, and the thickness of the diverter bag is recorded as T1; When 1000mm≤W0<1500mm, W1 is 390mm~410mm, and T1 is 125mm~135mm; When 1500mm≤W0<2000mm, W1 is 540mm~560mm, and T1 is 135mm~145mm; When W0 ≥ 2000 mm, W1 is 680-720 mm, and T1 is 145-155 mm; When W0≥2000mm or T0≥1000mm, two large rectangular aluminum outlets are respectively provided on two opposite large side surfaces of the diversion bag.

5. The method for preparing an aluminum alloy slab according to claim 4, wherein: The diversion bag meets at least one of the following conditions: (1) When 1000 mm ≤ W0 < 1500 mm and 200 mm ≤ T0 < 1500 mm, W1 is 390 mm to 410 mm, and T1 is 125 mm to 135 mm; (2) When 1500 mm ≤ W0 < 2000 mm and 600 mm ≤ T0 < 2000 mm, W1 is 540 mm to 560 mm, and T1 is 135 mm to 145 mm; (3) When 2000 mm ≤ W0 ≤ 3000 mm and 800 mm ≤ T0 ≤ 3000 mm, W1 is 680 to 720 mm, and T1 is 145 to 155 mm.

6. The method for preparing an aluminum alloy slab according to claim 4 or 5, characterized in that: The diversion bag meets at least one of the following conditions: (1) The material of the diversion bag is high silica fiber; (2) The material of the diversion bag is high-silica fiber, and the content of silicon oxide in the high-silica fiber is 95% to 98%; (3) The continuous heat-resistant temperature of the diversion bag is greater than 1000°C; (4) The thickness of the diversion bag material is 0.40mm~0.48mm; (5) The diversion bag is a rectangular trough structure; (6) The aluminum liquid permeability of the diversion bag is ≤0.2%.

7. The method for preparing an aluminum alloy slab according to claim 4 or 5, characterized in that: The diversion bag meets at least one of the following conditions: (1) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the diversion bag, and the material of the bottom aluminum outlet is a high-silica fiber interwoven mesh with a mesh size of 8 to 10; (2) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the diversion bag. The material of the bottom aluminum outlet is a high-silica fiber interwoven mesh with a thickness of 0.59mm~0.71mm; (3) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the diversion bag. When 1000mm≤W0<2000mm, the diameter of the bottom aluminum outlet is 54mm~56mm; (4) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the diversion bag. When 1000mm≤W0<2000mm and T0≤1000mm, the diameter of the bottom aluminum outlet is 54mm~56mm; (5) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the diversion bag. When W0 ≥ 2000 mm, the diameter of the bottom aluminum outlet is 59 mm to 61 mm; (6) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the diversion bag. When W0 ≥ 2000 mm and T0 ≥ 1000 mm, the diameter of the bottom aluminum outlet is 59 mm to 61 mm; (7) Two circular bottom aluminum outlets are symmetrically provided on the bottom surface of the diverter bag, and the centers of the bottom aluminum outlets are located on the width center line of the diverter bag; (8) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the diverter bag. The center of the bottom aluminum outlet is located on the width center line of the diverter bag. The distance between the center of the bottom aluminum outlet and the symmetry center of the bottom surface of the diverter bag is (0.25~0.35)×W1.

8. The method for preparing an aluminum alloy slab according to claim 4 or 5, characterized in that: The diversion bag meets at least one of the following conditions: (1) A rectangular small aluminum outlet is provided on two opposite small side surfaces of the diversion bag, the mesh number of the small aluminum outlet is 8 to 10, and the thickness of the material of the small aluminum outlet is 0.59 mm to 0.71 mm; (2) Two small side surfaces of the diversion bag are symmetrically provided with rectangular small aluminum outlets, the width of the small aluminum outlets is T1, and the height is 35-45 mm; (3) When W0≥2000mm or T0≥1000mm, two rectangular large aluminum outlets are respectively provided on the two opposite large sides of the diversion bag, the mesh number of the large aluminum outlets is 8~10 mesh, and the thickness of the material of the large aluminum outlets is 0.59mm~0.71mm; (4) When W0≥2000mm or T0≥1000mm, two rectangular large aluminum outlets are respectively provided on the two opposite large side surfaces of the diversion bag. The two large aluminum outlets on the same side surface are symmetrically arranged relative to the vertical center line of the large side surface. The distance between the large aluminum outlet and the vertical center line of the large side surface is (0.1~0.12)W1. (5) When W0≥2000mm or T0≥1000mm, two large rectangular aluminum outlets are respectively provided on the two opposite large side surfaces of the diversion bag, and the size of the large aluminum outlet is (0.15~0.25)W1×(35~45)mm.

9. The method for preparing an aluminum alloy slab according to claim 4 or 5, characterized in that: The smelting temperature is 720-750°C; and / or, during the smelting process, adding Mg when the temperature reaches 735-745°C; And / or, in step S3, the speed of the semi-continuous casting is 15-35 mm / min, the temperature of the semi-continuous casting is 680-710°C, and the cooling water flow rate during the semi-continuous casting is 40-80 m 3 / h; And / or, in step S4, the homogenization treatment includes primary homogenization and secondary homogenization performed sequentially, the temperature of the primary homogenization is 380-400° C., and the holding time is 6-8 hours; the temperature of the secondary homogenization is 460-480° C., and the holding time is 20-25 hours; And / or, in step S4, the heating rate of the primary homogenization treatment is 100-250°C / h, and the heating rate of the secondary homogenization treatment is 50-100°C / h.

10. The method for preparing an aluminum alloy slab according to claim 4 or 5, characterized in that: The furnace bottom degassing treatment includes: refining for 40 to 50 minutes through a furnace bottom degassing device; The online double degassing treatment is carried out by an online double degassing device, wherein the rotor speed is 230~250r / min, the Ar gas flow rate is 4.0~4.5m 3 / h, Cl2 gas flow rate 0.04~0.06 m 3 / h; The double-stage filtration process includes sequentially using a 30 ppi filter plate and a 50 ppi filter plate for filtration.

11. A method for preparing an aluminum alloy plate, characterized in that: The following steps are involved: Step A1, sawing an aluminum alloy ingot to obtain aluminum alloy slices, wherein the aluminum alloy ingot is the aluminum alloy slab according to any one of claims 1 to 3 or the aluminum alloy slab prepared by the method for preparing an aluminum alloy slab according to any one of claims 4 to 10; Step A2: subjecting the aluminum alloy slices to anodizing treatment, wherein the anodizing treatment includes: degreasing, water washing, alkali washing, neutralization, oxidation and sealing treatment.

12. The method for preparing an aluminum alloy plate according to claim 11, wherein: During the alkali washing, the concentration of the alkali solution is 80-100 g / L, and the alkali washing time is 1-2 min; And / or, during the neutralization process, the neutralizing solution used is a nitric acid solution with a mass concentration of 18% to 22%, and the neutralization time is 5 to 8 minutes; And / or, during the oxidation, the oxidizing agent used is a sulfuric acid solution with a mass concentration of 15% to 20%; And / or, the sealing treatment is performed in water at a temperature of 70-80° C. for 5-8 minutes.

13. An aluminum alloy plate, characterized in that: It is prepared by the preparation method according to claim 11 or 12.

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