Aluminum alloy slab ingot and preparation method thereof as well as aluminum alloy plate and preparation method thereof

Abstract

The invention provides an aluminum alloy slab ingot and a preparation method thereof as well as an aluminum alloy plate and a preparation method thereof. The aluminum alloy slab ingot comprises the following components in percentage by mass: 4.30%-5.20% of Mg, 0.40%-0.60% of Mn, 0.05%-0.15% of La, less than or equal to 0.25% of Si, less than or equal to 0.25% of Zn, less than or equal to 0.20% of Cr, less than or equal to 0.15% of Ti, less than or equal to 0.50% of Fe, less than or equal to 0.15% of inevitable impurities and the balance of Al, at the 1 / 4 thickness part of the aluminum alloy slab ingot, the average grain size is less than or equal to 90 microns, the maximum size of an intermetallic compound is less than or equal to 60 microns, and the average size of the intermetallic compound is less than or equal to 15 microns. The aluminum alloy slab ingot has good mechanical performance and machining resistance, and the ingot has high quality and yield when being used for machining aluminum alloy plate materials and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of aluminum alloys, and more particularly, to an aluminum alloy flat ingot and a method for preparing the same, an aluminum alloy sheet and a method for preparing the same. Background Art

[0002] 5083 aluminum alloy, with its good strength, excellent corrosion resistance and weldability, is widely used in fields such as maritime, automotive, aerospace, transportation, pressure vessels and refrigeration equipment. However, in the industrial production of high-magnesium aluminum alloys, especially large-sized ingots with a width ≥ 1000 mm, a long-existing problem is the annular segregation phenomenon that appears on the cross-section of the ingot, manifested as obvious color difference bands, accompanied by uneven alloy composition and the appearance of large-sized grains. This segregation not only affects the subsequent processing of the ingot, such as cracking easily occurring during the forging process, but also causes color differences on the surface of the product after anodic oxidation treatment, seriously affecting the aesthetics and performance of the product, and thus reducing the yield and market competitiveness.

[0003] Annular segregation is different from conventional macrosegregation. The latter does not show obvious coarse grain bands in low-magnification inspection, while annular segregation is clearly visible on the cross-section of the ingot. Coarse compounds and a relatively high hydrogen content are often accompanied in the annular segregation region, and the latter may cause porosity defects. Although there are already various flow distribution devices in the prior art for improving the fluidity and composition uniformity of the alloy melt, such as self-rotating flow distribution bags, double flow distribution devices, and flow distribution bags with reinforcing ribs and anti-deformation designs, these technologies have not systematically studied the effects of the flow distribution structure and the melting and casting process on the annular segregation, compound size, and hydrogen content of the ingot, nor have they selected a matching flow distribution bag size and structure according to the size of the ingot, which limits their role in suppressing annular segregation, refining grains, and eliminating coarse compounds.

[0004] Specifically, existing patents such as "A Self-Rotating Flow Distribution Bag and an Aluminum Alloy Casting Method" (CN 110976791 A), "Device and Method for Semi-Continuous Casting of Ultra-Wide Aluminum Alloy Flat Ingots" (CN 112548055 A), and "Casting Flow Divider and Design Method of Casting Flow Divider" (CN 117548635 A) mainly focus on improving the melt fluidity or improving macrosegregation, but fail to effectively solve the problem of insufficient filling at the corners and the center of the large surface of the large-sized ingot, nor do they involve methods for reducing the quantity, size, and aggregation size of porosity.

[0005] In summary, there is a lack of effective solutions in the prior art to comprehensively improve the annular segregation problem of large-sized high-magnesium aluminum alloy ingots, as well as the problems of uneven alloy composition distribution, inconsistent grain size, poor compound morphology, and excessive hydrogen content caused thereby. Summary of the Invention

[0006] The present invention provides an aluminum alloy flat ingot, a preparation method thereof, an aluminum alloy sheet and a preparation method thereof, so as to solve the problem of annular segregation generated in the cross section of large-size aluminum alloy ingots in the prior art.

[0007] To achieve the above object, according to one aspect of the present invention, there is provided an aluminum alloy flat ingot. By mass percentage, the composition of the aluminum alloy flat ingot includes: 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%, Ti content ≤ 0.15%, Fe content ≤ 0.50%, the total sum of inevitable impurities ≤ 0.15%, and the balance is Al; at the 1 / 4 thickness of the aluminum alloy flat ingot, the average grain size ≤ 90 μm, the maximum size of intermetallic compounds ≤ 60 μm, and the average size of intermetallic compounds ≤ 15 μm.

[0008] Further, the width of the aluminum alloy flat ingot ≥ 1000 mm;

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

[0010] Further, the aluminum alloy flat ingot satisfies at least one of the following conditions:

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

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

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

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

[0015] To achieve the above object, according to one aspect of the present invention, there is provided a method for preparing an aluminum alloy slab ingot of any one of the above, the preparation method comprising the following steps: Step S1, proportioning and melting according to the composition of the aluminum alloy slab ingot to obtain an aluminum alloy melt; Step S2, purifying the aluminum alloy melt to obtain a purified aluminum alloy melt; the purification treatment includes: subjecting the aluminum alloy melt to bottom degassing treatment, on-line double degassing treatment and double-stage filtration treatment in sequence; Step S3, diverting the purified aluminum alloy melt through a diverting bag and performing semi-continuous casting to obtain an as-cast aluminum alloy ingot blank; Step S4, performing homogenization treatment on the as-cast aluminum alloy ingot blank to obtain the aluminum alloy slab ingot; wherein, the width of the aluminum alloy slab ingot is denoted as W0, the thickness of the aluminum alloy slab ingot is denoted as T0, and T0 ≤ W0, the width of the diverting bag is denoted as W1, and the thickness of the diverting bag is denoted as T1; when 1000 mm ≤ W0 < 1500 mm, W1 is 390 mm to 410 mm, and T1 is 125 mm to 135 mm; when 1500 mm ≤ W0 < 2000 mm, W1 is 540 mm to 560 mm, and T1 is 135 mm to 145 mm; when W0 ≥ 2000 mm, W1 is 680 to 720 mm, and T1 is 145 mm to 155 mm.

[0016] Further, the diverting 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 mm to 155 mm.

[0020] Further, the diverting bag satisfies at least one of the following conditions:

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

[0022] (2) The material of the diverting 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 resistance temperature of the diverting bag > 1000 °C;

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

[0025] (5) The shunt bag is a cuboid groove-like structure;

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

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

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

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

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

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

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

[0033] (6) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the shunt 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 shunt 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 arranged on the bottom surface of the shunt bag, and the centers of the bottom aluminum outlets are located on the width center line of the shunt bag;

[0036] (9) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the shunt bag, the centers of the bottom aluminum outlets are located on the width center line of the shunt bag, and the distance between the centers of the bottom aluminum outlets and the symmetric center of the bottom surface of the shunt bag is (0.25 - 0.35) × W1.

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

[0038] (1) Rectangular small aluminum outlets are respectively arranged on two opposite small side surfaces of the shunt bag;

[0039] (2) Rectangular small aluminum outlets are respectively arranged on two opposite small side surfaces of the shunt bag, the mesh number of the small aluminum outlets is 8 - 10 meshes, and the thickness of the material of the small aluminum outlets is 0.59 mm - 0.71 mm;

[0040] (3) Rectangular small aluminum outlets are symmetrically arranged on two opposite small side surfaces of the shunt bag respectively, the width of the small aluminum outlets is T1, and the height is 35 - 45 mm;

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

[0042] (5) When W0 ≥ 2000 mm or T0 ≥ 1000 mm, two rectangular large aluminum outlets are respectively arranged on two opposite large side surfaces of the shunt bag, the mesh number of the large aluminum outlets is 8 - 10 meshes, and the thickness of the material of the large aluminum outlets is 0.59 mm - 0.71 mm;

[0043] (6) When W0 ≥ 2000 mm or T0 ≥ 1000 mm, two rectangular large aluminum outlets are respectively arranged on two opposite large side surfaces of the shunt bag, two large aluminum outlets on the same side surface are symmetrically arranged with respect to the vertical center line of the large side surface, and the large aluminum outlets are (0.1 - 0.12)W1 away from the vertical center line of the large side surface;

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

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

[0046] And / or, during the smelting process, Mg is added 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 carried out successively. The temperature of the primary homogenization is 380 - 400 °C, and the heat preservation time is 6 - 8 h; the temperature of the secondary homogenization is 460 - 480 °C, and the heat preservation time is 20 - 25 h;

[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 bottom degassing treatment of the furnace includes: refining for 40 - 50 min through a bottom degassing device of the furnace;

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

[0052] The double - stage filtration treatment includes filtering successively using a 30 ppi filter plate and a 50 ppi filter plate.

[0053] According to another aspect of the present application, a method for preparing an aluminum alloy sheet is provided. The preparation method includes the following steps: Step A1, sawing an aluminum alloy ingot to obtain an aluminum alloy slice, where the aluminum alloy ingot is any one of the above - mentioned aluminum alloy flat ingots or an aluminum alloy flat ingot prepared by the preparation method of any one of the above - mentioned aluminum alloy flat ingots; Step A2, subjecting the aluminum alloy slice to an anodic oxidation treatment, and the anodic oxidation treatment includes: degreasing, water washing, alkali washing, neutralization, oxidation, and sealing hole 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 neutralization solution used is a nitric acid solution with a mass concentration of 18% - 22%, and the neutralization time is 5 - 8 min;

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

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

[0058] According to still another aspect of the present application, an aluminum alloy sheet is provided, and the aluminum alloy sheet is prepared by the preparation method of any one of the above - mentioned aluminum alloy sheets.

[0059] By applying the technical solution of the present invention, by controlling the contents of elements such as Mg, Mn, La, Si, Zn, and Cr in the aluminum alloy flat ingot, and having a smaller average grain size and smaller intermetallic compound size at the 1 / 4 thickness of the aluminum alloy flat ingot, the alloy composition is uniform, and there is no annular segregation in the cross-section of the aluminum alloy flat ingot. This aluminum alloy flat ingot has good mechanical properties and workability. Using this ingot for the processing of aluminum alloy plate materials, etc., has high quality and a high finished product rate, and can effectively reduce or even avoid phenomena such as forging cracking and surface color difference of anodized products. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The specification drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0061] Figure 1 Shows a schematic structural diagram of a preparation device for an aluminum alloy flat ingot provided by an embodiment of the present invention;

[0062] Figure 2 Shows an isometric view of a split bag provided by an embodiment of the present invention;

[0063] Figure 3 Shows Figure 2 a top view of the split bag in;

[0064] Figure 4 Shows Figure 3 an enlarged view of the split bag at position A in;

[0065] Figure 5 Shows Figure 2 a side view of the split bag in;

[0066] Figure 6 Shows Figure 2 a front view of the split bag in;

[0067] Figure 7 Shows Figure 6 an enlarged view of the split bag at position B in;

[0068] Figure 8 Shows a cross-sectional photo of the aluminum alloy flat ingot prepared in Example 1 (without annular segregation);

[0069] Figure 9 Shows a cross-sectional photo of the aluminum alloy flat ingot prepared in Comparative Example 1 (with annular segregation);

[0070] Figure 10 Shows a metallographic photo of the aluminum alloy flat ingot prepared in Example 1;

[0071] Figure 11The metallographic photos with film coating of the aluminum alloy flat ingot prepared in Example 1 are shown;

[0072] Figure 12 The metallographic photos of the aluminum alloy flat ingot prepared in Comparative Example 1 are shown;

[0073] Figure 13 The metallographic photos with film coating of the aluminum alloy flat ingot prepared in Comparative Example 1 are shown.

[0074] Among them, the above-mentioned drawings include the following reference numerals: 10, shunt bag; 11, small aluminum outlet; 12, large aluminum outlet; 13, bottom aluminum outlet; 20, mold; 40, dummy bar head. Detailed implementation manners

[0075] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0076] As analyzed in the background art of the present application, there is a problem of ring segregation in the cross-section of large-sized aluminum alloy ingots in the prior art. To solve this problem, the present application provides an aluminum alloy flat ingot and its preparation method, an aluminum alloy sheet and its preparation method.

[0077] According to a typical implementation manner of the present application, an aluminum alloy flat ingot is provided. By mass percentage, the components of the aluminum alloy flat ingot include: 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%, Ti content ≤ 0.15%, Fe content ≤ 0.50%, the total sum of inevitable impurities ≤ 0.15%, and the balance is Al; at the 1 / 4 thickness of the aluminum alloy flat ingot, the average grain size ≤ 90μm, the maximum size of the intermetallic compound ≤ 60μm, and the average size of the intermetallic compound ≤ 15μm.

[0078] For the aluminum alloy flat ingot of the present application, by controlling the contents of elements such as Mg, Mn, La, Si, Zn, and Cr, and having a smaller average grain size and smaller size of intermetallic compounds at the 1 / 4 thickness of the aluminum alloy flat ingot, the alloy components are uniform, and there is no ring segregation in the cross-section of the aluminum alloy flat ingot. This aluminum alloy flat ingot has good mechanical properties and workability. Using this ingot for the processing of aluminum alloy sheet materials, etc., has high quality and yield, and can effectively reduce or even avoid phenomena such as forging cracking and surface color difference of anodized products.

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

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

[0081] For example, at the 1 / 4 thickness of the aluminum alloy flat ingot, the average size of the intermetallic compound is 3μm, 5μm, 7μm, 9μm, 11μm, 13μm, 15μm or any value within the above range. Preferably, the average size of the intermetallic compound at the 1 / 4 thickness of the aluminum alloy flat ingot is 5 - 15μm, 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 flat ingot ≥ 1000mm. Due to the serious circular segregation of the large - sized 5083 aluminum alloy ingot, the present application controls the grain size and the size of the intermetallic compound at the 1 / 4 thickness of the aluminum alloy flat ingot, so that the alloy composition on the cross - section of the large - sized flat ingot, especially the flat ingot with a width ≥ 1000mm, is uniform and there is no circular segregation.

[0083] In some embodiments of the present application, the solid hydrogen content of the aluminum alloy flat ingot ≤ 0.12ug / g. The lower hydrogen content helps to improve the formability of the material and reduce the risk of internal cracks, making it an ideal raw material for large - sized plates and widely used in fields such as shipbuilding and the outer shells of rail transit vehicles, meeting the requirements of these industries for material size stability and low hydrogen brittleness. Preferably, the solid hydrogen content of the aluminum alloy flat ingot is 0.07 - 0.12ug / g, which not only has more stable mechanical properties but also can better balance performance and processing costs.

[0084] According to another typical embodiment of the present application, a method for preparing an aluminum alloy flat ingot is provided. The preparation method includes the following steps: Step S1, proportioning and melting according to the composition of the aluminum alloy flat ingot to obtain an aluminum alloy melt; the composition of the aluminum alloy flat ingot includes: 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%, Ti content ≤ 0.15%, Fe content ≤ 0.50%, the total sum of inevitable 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 includes: subjecting the aluminum alloy melt to bottom degassing treatment, online double degassing treatment, and two-stage filtration treatment in sequence; Step S3, diverting the purified aluminum alloy melt through a diverting bag and performing semi-continuous casting to obtain an as-cast aluminum alloy ingot blank; Step S4, performing homogenization treatment on the as-cast aluminum alloy ingot blank to obtain an aluminum alloy flat ingot; wherein, as Figure 1 shown in FIG. 1 or FIG. 2, the width of the aluminum alloy flat ingot is denoted as W0, the thickness of the aluminum alloy flat ingot is denoted as T0, and T0 ≤ W0. The width of the diverting bag 10 is denoted as W1, and the thickness of the diverting bag 10 is denoted as T1; when 1000 mm ≤ W0 < 1500 mm, W1 is 390 mm - 410 mm, and T1 is 125 mm - 135 mm; when 1500 mm ≤ W0 < 2000 mm, W1 is 540 mm - 560 mm, and T1 is 135 mm - 145 mm; when W0 ≥ 2000 mm, W1 is 680 - 720 mm, and T1 is 145 mm - 155 mm.

[0085] In Figure 1 , W0 is the width of the aluminum alloy flat ingot, T0 is the thickness of the aluminum alloy flat ingot, and W0 ≥ T0. H0 is the height of the aluminum alloy flat ingot. The end of the aluminum-magnesium alloy ingot is the dummy bar head 40. In Figure 2 , W1 is the width of the diverting bag 10, and T1 is the thickness of the diverting bag 10.

[0086] This application improves the flow distribution of molten aluminum in the ingot by using a distributor bag 10 with different structural dimensions according to aluminum alloy flat ingots of different sizes, enhances the filling fullness and stability of molten aluminum during the starting stage of casting, and ensures complete filling at positions such as the corners and the centers of large surfaces. At the same time, it reduces the probability, intensity, and action range of molten aluminum turbulence during the stable casting stage, avoids violent agitation of molten aluminum in local areas, and improves the uniformity of alloy composition distribution. Meanwhile, by using a suitable distributor bag 10, in combination with the optimal element composition combination of 5083 alloy ingots, a purification treatment process, and a semi-continuous casting process, the cooling rate of the ingot is increased, the temperature difference between the center and the edge of the ingot is reduced, the grains are refined, and coarse compounds (such as AIMgCrMn phase, AIMgMnFe phase, and AIMgMn phase) are eliminated, and compounds with uniform size (AIMgCrMnFe phase) are generated. At the 1 / 4 thickness of the aluminum alloy flat ingot prepared by the above preparation method, the average grain size ≤ 90 μm, the maximum size of intermetallic compounds ≤ 60 μm, and the average size of intermetallic compounds ≤ 15 μm, so that large-sized 5083 aluminum alloy ingots with an ingot width ≥ 1000 mm no longer produce annular segregation defects, significantly improving the comprehensive quality of subsequent finished parts.

[0087] In some embodiments of the present application, 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. When the size of the aluminum alloy flat ingot is within the above range, using a distributor bag with W1 being 390 mm to 410 mm and T1 being 125 mm to 135 mm can further reduce the probability, intensity, and action range of molten aluminum turbulence, thereby making the structure of the aluminum alloy flat ingot more uniform and obtaining better comprehensive performance.

[0088] In some embodiments of the present application, 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. When the size of the aluminum alloy flat ingot is within the above range, using a distributor bag with W1 being 540 mm to 560 mm and T1 being 135 mm to 145 mm can further reduce the probability, intensity, and action range of molten aluminum turbulence, thereby making the structure of the aluminum alloy flat ingot more uniform and obtaining better comprehensive performance.

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

[0090] In some embodiments of the present application, the material of the flow splitting bag 10 is high silica fiber, that is, high-purity amorphous continuous silica fiber. Among them, the content of silica in the high silica fiber is 95% - 98%, and it has excellent heat resistance. Among them, the aluminum outlet of the flow splitting bag 10 is a high silica fiber interwoven net, and the rest is a high silica fiber cloth. In some embodiments of the present application, the continuous heat-resistant temperature of the flow splitting bag 10 > 1000 °C.

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

[0092] In some embodiments of the present application, the flow splitting bag 10 is a cuboid groove-like structure.

[0093] In some embodiments of the present application, the aluminum liquid permeability of the flow splitting bag 10 ≤ 0.2%. Among them, the permeability represents the proportion of the volume flow of the fluid passing through the medium per unit area per unit time under the drive of gravity to the total volume of the medium.

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

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

[0096] In some embodiments of the present application, when 1000 mm ≤ W0 < 2000 mm, the diameter of the bottom tapping port is 54 mm to 56 mm. With a bottom tapping port of this size, when preparing an aluminum alloy flat ingot of the above size, the melt can have fewer turbulences and a smaller action range during the casting process, avoiding the thickness range of 1 / 3 to 1 / 4 where composition segregation and porosity are prone to occur. In particular, when 1000 mm ≤ W0 < 2000 mm and T0 ≤ 1000 mm, the diameter of the bottom tapping port is 54 mm to 56 mm, which can better adjust the flow state of the alloy melt during the casting process, reduce the number and action range of turbulences, 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 tapping port is 59 mm to 61 mm. With a bottom tapping port of this size, when preparing an aluminum alloy flat ingot of the above size, the melt can have fewer turbulences and a smaller action range during the casting process, avoiding the thickness range of 1 / 3 to 1 / 4 where composition segregation and porosity are prone to occur. In particular, when W0 ≥ 2000 mm and T0 ≥ 1000 mm, the diameter of the bottom tapping port is 59 mm to 61 mm, which can better adjust the flow state of the alloy melt during the casting process of this size, reduce the number and action range of turbulences, and improve the overall quality of the ingot.

[0098] In some embodiments of the present application, the center of the bottom tapping port is located on the width center line of the flow splitting bag 10; preferably, the distance between the center of the bottom tapping port and the symmetry center of the bottom surface of the flow splitting bag 10 is (0.25 to 0.35) × W1, which can make the melt flow of large-sized ingots more stable, reducing the generation probability, action intensity, and range of turbulences during the flow of the aluminum liquid in the mold and the liquid cavity.

[0099] In some embodiments of the present application, as Figure 2 、 Figure 5 shown, rectangular small tapping ports 11 are respectively arranged on two opposite small side surfaces of the flow splitting bag 10. This design ensures the smooth flow of the melt when it enters the mold, reduces the turbulence phenomenon, is conducive to forming a uniform and dense microstructure, and is suitable for manufacturing aluminum alloy plates that require high flatness, such as high-grade building decoration materials, high-grade furniture panels, etc. The material of the small tapping port 11 can also be a high-silica fiber interwoven mesh. Preferably, the mesh number of the small tapping port is 8 to 10 meshes, and the thickness is 0.59 mm to 0.71 mm. Preferably, the small tapping ports 11 on two opposite small side surfaces of the flow splitting bag 10 are symmetrically arranged. The width of the small tapping port is T1, that is, the same as the width of the flow splitting bag 10, and the height is 35 to 45 mm.

[0100] In some embodiments of the present application, as Figure 2 、 6As shown in FIGS. 7, when W0≥2000 mm or T0≥1000 mm, two rectangular large aluminum outlets 12 are respectively arranged on two opposite large side surfaces of the shunt bag 10. When the width or thickness of the flat ingot is relatively large, arranging the large aluminum outlets 12 on the large side surface of the shunt bag 10 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 0.59 mm - 0.71 mm. Preferably, the two large aluminum outlets on the same side surface are symmetrically arranged with respect to the vertical center line of the large side surface, and the distance between the large aluminum outlet and the vertical center line of the large side surface is (0.1 - 0.12)W1, which is beneficial 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, where 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 following specifically introduces the influence of process parameters in each step of the preparation method on the effect in combination with 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 alloying elements, promote grain refinement, and at the same time avoid excessive evaporation of alloy components at high temperatures, maintaining the chemical balance of the alloy, which is suitable for manufacturing aluminum alloy products that require high toughness and good formability.

[0103] In some embodiments of the present application, the purification treatment includes: successively performing bottom degassing treatment, on-line double degassing treatment, and double-stage filtration treatment on the aluminum alloy melt, which can effectively reduce the hydrogen content in the melt and improve the purity of the melt. Among them, the bottom degassing treatment includes: refining for 40 - 50 min through a bottom degassing device. The on-line double degassing treatment is carried out through an on-line double degassing device, where the rotor speed is 230 - 250 r / min, the Ar gas flow rate is 4.0 - 4.5 m 3 / h, and the Cl2 gas flow rate is 0.04 - 0.06 m 3 / h; the double-stage filtration treatment includes filtering successively with a 30 ppi filter plate and a 50 ppi filter plate. By combining the above purification treatment process with the shunt 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 carried out in sequence. The temperature of the primary homogenization is 380 - 400 °C, and the holding time is 6 - 8 h; the temperature of the secondary homogenization is 460 - 480 °C, and the holding time is 20 - 25 h. The above semi - continuous casting process is adapted to the flow - splitting bag 10, which 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 °C / h, and the heating rate of the secondary homogenization treatment is 50 - 100 °C / h.

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

[0107] According to another typical embodiment of the present application, a method for preparing an aluminum alloy sheet is provided. The preparation method includes the following steps: Step A1, saw - cutting an aluminum alloy ingot to obtain an aluminum alloy slice. The aluminum alloy ingot is any one of the above - mentioned aluminum alloy flat ingots or an aluminum alloy flat ingot prepared by the preparation method of any one of the above - mentioned aluminum alloy flat ingots; Step A2, performing anodic oxidation treatment on the aluminum alloy slice. The anodic oxidation treatment includes: degreasing, water washing, alkali washing, neutralization, oxidation, and sealing treatment.

[0108] Since the 1 / 4 thickness of the above - mentioned aluminum alloy flat ingot has a smaller average grain size, a smaller size of intermetallic compounds, uniform alloy composition, and no ring - shaped segregation in the cross - section of the aluminum alloy flat ingot. Saw - cutting and anodic oxidation treatment are carried out on it, and the prepared aluminum alloy sheet has a higher yield, and the finished product has higher mechanical strength and surface quality.

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

[0110] In some embodiments of the present application, degreasing includes soaking in an aqueous solution of neutral degreasing powder at 30 - 36 g / L. Preferably, the aqueous solution of neutral degreasing powder contains sodium alkylbenzene sulfonate, dextran, polysaccharide, and sodium tripolyphosphate with a mass ratio of 5:2:2:1; preferably, the soaking time is 3 - 10 min, 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 neutralization, the neutralizing solution used is a nitric acid solution with a mass concentration of 18% - 22%, and the neutralization time is 5 - 8 min.

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

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

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

[0116] According to another typical embodiment of the present application, an aluminum alloy sheet is provided, which is prepared by the above preparation method. Since the above aluminum alloy ingot is used as the raw material and through the above preparation process, the aluminum alloy sheet prepared in the present application has good mechanical properties and surface quality, and can be widely applied to the preparation of ships, as well as welding parts of automobiles and airplanes, subway light rails, pressure vessels that require strict fire prevention (such as liquid tank trucks, refrigerated trucks, refrigerated containers), refrigeration devices, television towers, drilling equipment, transportation equipment, missile parts, armor, etc.

[0117] The following further describes the present application in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present application.

[0118] The material of the shunt bag used in the examples and comparative examples of the present application is high-silica fiber, the silicon dioxide content is 95 - 98%, and the continuous heat-resistant temperature > 1000 °C; among them, the material of each aluminum outlet is a high-silica fiber intertwined mesh, with a mesh number of about 8 - 10 meshes, a thickness of 0.65 ± 0.06 mm, and a weight of 295 g / ㎡; the remaining parts are high-silica fiber cloth, with a thickness of 0.44 ± 0.04 mm, a weight of 420 g / ㎡, and the aluminum liquid penetration rate ≤ 0.2%.

[0119] Example 1

[0120] (1)Prepare the ingredients according to the following aluminum alloy components: by mass percentage, Mg: 4.30%, Mn: 0.40%, Si: 0.1%, Zn: 0.05%, Cr: 0.10%, Ti: 0.10%, Fe: 0.10%, the total sum of inevitable impurities ≤ 0.15%, and the balance is Al; mix the components except Mg and conduct melting, set the melting temperature at 750 - 770 °C, after complete melting, when the melt cools down to 740 °C, add pure Mg to obtain the aluminum alloy melt.

[0121] (2)Conduct purification treatment on the above aluminum alloy melt. Specifically, refine the aluminum alloy melt obtained by melting using the bottom degassing system of the furnace, set the time at 40 min; then conduct degassing using an on-line dual degassing device, set the rotor speed at 230 rpm, the Ar gas flow rate at 4.0 m 3 / h, and the Cl2 gas flow rate at 0.04 m 3 / h; filter the degassed aluminum alloy melt using 30 ppi and 50 ppi filter plates. Measure the hydrogen content of the aluminum-magnesium alloy melt after double-stage filtration on-line, the testing equipment is the ABB hydrogen detector ALSCAN, and the hydrogen content is 0.09 ml / 100 g Al.

[0122] (3)Divert the above purified aluminum alloy melt through a diversion bag. The width W1 of the diversion bag is 400 mm, the thickness T1 is 130 mm, the height H1 is 125 mm, the bottom aluminum outlet is circular, with a diameter of 55 mm, 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 surface of the diversion bag is 120 mm; the small aluminum outlet on the small side is rectangular, with dimensions of 130 mm × 40 mm (height), and there is no aluminum outlet on the large side. The diverted alloy melt is subjected to semi-continuous casting, the semi-continuous casting speed is 35 mm / min, the casting temperature is 710 °C, and the cooling water flow rate during semi-continuous casting is 40 m 3 / h to obtain an aluminum alloy as-cast ingot blank with dimensions of 1320 (W0) × 400 (T0).

[0123] (4)Conduct homogenization annealing treatment on the above aluminum alloy as-cast ingot blank. Start heating the ingot blank at room temperature, with a heating rate of 250 °C / h, heat up to 400 °C and hold for 6 h for primary homogenization; heat up to 480 °C at a heating rate of 100 °C / h, and the holding time is 20 h for secondary homogenization; then air-cool to 250 °C, and subsequently air-cool to room temperature to obtain an aluminum alloy flat ingot.

[0124] After sawing the aluminum alloy flat ingot prepared in this example, the cross-section of the slice is as Figure 8 shown. And Figure 10 and 11The metallographic photos and film-covered metallographic photos of the aluminum alloy flat ingot prepared in this embodiment are shown respectively.

[0125] The following method is used to test the composition segregation of the aluminum alloy flat ingot prepared in this embodiment: The aluminum alloy flat ingot is sawn, and a cross-sectional slice is taken. The instrument is calibrated with a standard sample by direct-reading spectrometry, and the main element content of the massive sample is quickly detected. As the main element of 5083 aluminum alloy, the distribution law of Mg solute element in the cross-section along the thickness direction is center negative segregation, that is, the content of Mg element in the center region is low, resulting in center negative segregation; at the quarter thickness of the cross-section, the Mg element shows positive segregation, that is, the content of Mg element in this region is high. In the aluminum alloy flat ingot of this embodiment, in the thickness direction of the Mg element, negative segregation appears in the middle, and positive segregation appears at the quarter thickness. The maximum negative segregation degree is 0.46, and the maximum positive segregation degree is 0.73.

[0126] Example 2

[0127] (1) Charge materials according to the following aluminum alloy components: by mass percentage, Mg: 4.75%, Mn: 0.50%, Si: 0.17%, Zn: 0.12%, Cr: 0.15%, Ti: 0.13%, Fe: 0.20%, the total sum of inevitable impurities ≤ 0.15%, and the balance is Al; mix the components except Mg and carry out melting, and set the melting temperature at 750 - 770 °C. After all are melted, pure Mg is added when the melt cools down to 740 °C to obtain an aluminum alloy melt.

[0128] (2) Carry out purification treatment on the above aluminum alloy melt. Specifically, the aluminum alloy melt obtained by melting is refined using a bottom degassing system in the furnace, and the time is set to 45 min; then degassing is carried out by an on-line dual degassing device, the rotor speed is set to 240 rpm, the Ar gas flow rate is 4.3 m 3 / h, and the Cl2 gas flow rate is 0.05 m 3 / h; the degassed aluminum alloy melt is filtered using 30 ppi and 50 ppi filter plates. The hydrogen content of the double-stage filtered aluminum-magnesium alloy melt is measured on-line, and the test equipment is an ABB hydrogen detector ALSCAN, and the hydrogen content is 0.08 ml / 100 g Al.

[0129] (3) The aluminum alloy melt after the above purification treatment is diverted through a diverter bag. The width W1 of the diverter bag is 550mm, the thickness T1 is 140mm, the height H1 is 125mm, the bottom aluminum outlet is circular, and the diameter is 60mm. The center of the bottom aluminum outlet is located on the width center line of the diverter bag, and the distance from the symmetry center of the bottom surface of the diverter bag is 165mm; the small aluminum outlet on the small side is rectangular, with a size of 140mm×40mm (height), and 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, and 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 dimensions of 1550 (W0) × 1050 (T0).

[0130] (4) The aluminum alloy cast ingot is subjected to a homogenization annealing treatment. The ingot is initially heated at room temperature at a heating rate of 170°C / h, and the temperature is raised to 390°C and kept at this temperature for 7 hours for primary homogenization. The ingot is then heated to 470°C at a heating rate of 75°C / h and kept at this temperature for 23 hours for secondary homogenization. The ingot is then air-cooled to 250°C and subsequently 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 inevitable 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) Purify the aluminum alloy melt. 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 aluminum alloy melt after degassing is filtered by 30ppi and 50ppi filter plates. The aluminum-magnesium alloy melt after double-stage filtration is tested for hydrogen online, and the test equipment is ABB hydrogen tester ALSCAN, and the hydrogen content is 0.07ml / 100g Al.

[0134] (3) The purified aluminum alloy melt is shunted through a shunting bag. The width W1 of the shunting bag is 700 mm, the thickness T1 is 150 mm, the height H1 is 125 mm. The bottom aluminum outlet is circular with a diameter of 60 mm. The center of the bottom aluminum outlet is located on the width center line of the shunting bag, and the distance from the symmetric center of the bottom surface of the shunting bag is 210 mm. The small aluminum outlet on the small side is rectangular with dimensions of 150 mm × 40 mm (height). There are two large aluminum outlets on each large side, and the dimensions of the large aluminum outlets are 140 mm × 40 mm. The two large aluminum outlets on the same side are symmetrically arranged with respect to the vertical center line of the large side, and the large aluminum outlets are 77 mm away from the vertical center line of the large side. The shunted alloy melt is subjected to semi - continuous casting. The speed of semi - continuous casting is 20 mm / min, the casting temperature is 710 °C, and the cooling water flow rate during semi - continuous casting is 70 m 3 / h, obtaining an as - cast ingot blank of aluminum alloy with dimensions of 2200 (W0) × 900 (T0).

[0135] (4) The above - mentioned as - cast ingot blank of aluminum alloy is subjected to homogenization annealing treatment. The ingot blank is heated starting from room temperature at a heating rate of 100 °C / h, heated to 380 °C and held for 8 h for primary homogenization; heated to 460 °C at a heating rate of 50 °C / h and held for 25 h for secondary homogenization; then air - cooled to 250 °C and subsequently 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, the casting temperature is 680 °C, and the cooling water flow rate is 40 m 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), during semi - continuous casting, the casting speed is, the casting temperature is 730 °C, and the cooling water flow rate is 60 m 3 / h.

[0146] Example 9

[0147] The difference from Example 1 is that in step (2), the refining time of the bottom - furnace degassing system is set to 50 min.

[0148] Online hydrogen measurement is carried out on the aluminum - magnesium alloy melt after double - stage filtration. The testing equipment is the ABB hydrogen - measuring instrument ALSCAN, and the hydrogen content is 0.08 ml / 100g Al.

[0149] Example 10

[0150] The difference from Example 1 is that in step (2), degassing is carried out through an online double - degassing device. Among them, the Ar gas flow rate is 4.5 m 3 / h, and the Cl2 gas flow rate is 0.06 m 3 / h.

[0151] Online hydrogen measurement is carried out on the aluminum - magnesium alloy melt after double - stage filtration. The testing equipment is the ABB hydrogen - measuring instrument ALSCAN, and the hydrogen content is 0.08 ml / 100g Al.

[0152] Example 11

[0153] The difference from Example 1 is that in step (2), degassing is carried out through an online double - degassing device. Among them, the rotor speed is 250 r / min.

[0154] Online hydrogen measurement is carried out on the aluminum - magnesium alloy melt after double - stage filtration. The testing equipment is the ABB hydrogen - measuring instrument ALSCAN, and the hydrogen content is 0.08 ml / 100g Al.

[0155] Example 12

[0156] The difference from Example 1 is that in step (4), homogenization annealing treatment is carried out. The ingot blank starts to be heated at room temperature, the heating rate is 280 °C / h, it is heated to 400 °C and held for 6 h for the first - stage homogenization; it is heated to 480 °C at a heating rate of 140 °C / h, and the holding time is 20 h for the second - stage homogenization; then it is 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 lies in that in step (4), homogenization annealing treatment is carried out. The ingot blank starts to be heated at room temperature, the heating rate is 100 °C / h, it is heated to 400 °C and held for 6 h for the first-stage homogenization; it is heated to 480 °C at a heating rate of 50 °C / h, and the holding time is 20 h for the second-stage homogenization; then it is 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 lies in that in step (4), homogenization annealing treatment is carried out. The ingot blank starts to be heated at room temperature, the heating rate is 250 °C / h, it is heated to 410 °C and held for 6 h for the first-stage homogenization; it is heated to 490 °C at a heating rate of 100 °C / h, and the holding time is 20 h for the second-stage homogenization; then it is 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 lies in that in step (4), homogenization annealing treatment is carried out. The ingot blank starts to be heated at room temperature, the heating rate is 250 °C / h, it is heated to 380 °C and held for 6 h for the first-stage homogenization; it is heated to 460 °C at a heating rate of 100 °C / h, and the holding time is 20 h for the second-stage homogenization; then it is 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 lies in that in step (3), the diameter of the bottom aluminum outlet is 60 mm.

[0165] Comparative Example 1

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

[0167] After the aluminum alloy flat ingot prepared in this comparative example is sawed, the cross-section of the slice is as Figure 9 shown. And, Figure 12 and 13 show the metallographic photo and the metallographic photo with coating film of the aluminum alloy flat ingot prepared in this comparative example.

[0168] The aluminum alloy flat ingot prepared in this comparative example was subjected to composition segregation testing in the same manner as in Example 1, and the results were as follows: In the thickness direction of the Mg element, negative segregation was presented in the middle, and positive segregation of the Mg element was presented at a 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 lies in that the flow splitting bag used in step (3) is different. The width W1 of the flow splitting bag is 330 mm, the thickness T1 is 130 mm, there is no bottom aluminum outlet and the aluminum outlet on the large side, and there is a rectangular small aluminum outlet on each small side, with a size of 130 mm × 40 mm (height).

[0171] Comparative Example 3

[0172] The difference from Example 3 lies in that the flow splitting bag used in step (3) is different. The width W1 of the flow splitting bag is 330 mm, the thickness T1 is 130 mm, there is no bottom aluminum outlet and the aluminum outlet on the large side, and there is a rectangular small aluminum outlet on each small side, 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 molten aluminum alloy obtained by melting was refined using a bottom degassing system in the furnace, and the time was set to 40 min; then degassing was carried out using an on-line degassing device, the rotor speed was set to 240 rpm, and the Ar gas flow rate was 5 m 3 / h; the degassed molten aluminum alloy was filtered using a 30 ppi filter plate. The hydrogen content of the double-filtered aluminum-magnesium alloy melt was measured on-line, and the test equipment was an ABB hydrogen analyzer ALSCAN, and the hydrogen content was 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 molten aluminum alloy obtained by melting was refined using a bottom degassing system in the furnace, and the time was set to 40 min; then degassing was carried out using an on-line degassing device, the rotor speed was set to 240 rpm, and the Ar gas flow rate was 5 m 3 / h; the degassed molten aluminum alloy was filtered using a 50 ppi filter plate. The hydrogen content of the double-filtered aluminum-magnesium alloy melt was measured on-line, and the test equipment was an ABB hydrogen analyzer ALSCAN, and the hydrogen content was 0.14 ml / 100 g Al.

[0177] Comparative Example 6

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

[0179] The above-mentioned aluminum alloy flat ingots are tested according to the following method. The test results are listed in Table 1 below. Among them, the sampling positions for the average grain size test, intermetallic compound size test, solid-state hydrogen measurement, and porosity agglomeration size test of the ingot are all at 1 / 4 of the thickness.

[0180] High-magnification microstructure detection: Sample pretreatment: grinding, polishing, corrosion, anodizing for film formation; Detection basis: GB / T 3246.1-2012; Detection equipment: OLYMPUS GX51 metallurgical microscope / JCS-049; Environmental conditions: 23 °C.

[0181] Low-magnification microstructure detection: Sample pretreatment: grinding, corrosion treatment; Detection basis: GB / T 3246.2-2012; Detection equipment: camera; Environmental conditions: 23 °C.

[0182] Average grain size test: Select 5 metallographic film-covered photos at 500 times magnification, process them using the image processing software Image-ProPlus, and statistically calculate the grain size values of the entire photo. Take the average of the values of the 5 photos.

[0183] Intermetallic compound size test: Select 5 scanning photos at 500 times magnification, process them using the image processing software Image-ProPlus, and statistically calculate the intermetallic compound size values of the entire photo. Take the average of the values of the 5 photos.

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

[0185] Porosity agglomeration size test: Select 5 metallographic microstructure photos at 200 times magnification, process them using the image processing software Image-ProPlus, and statistically calculate the porosity size values of the entire photo. Take the average of the values of the 5 photos.

[0186] Table 1

[0187]

[0188] Application Example 1

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

[0190] The aluminum alloy flat ingots were sawed, and the cross-sectional slice thickness was 20 mm. Anodic oxidation treatment was carried out on the aluminum alloy slices. The anodic oxidation process flow was: 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 → alkali washing (80 g / L, 1 min) → water washing → neutralization (volume ratio of HNO3 to H2O is 3:7, 5 min) → water washing → oxidation (mass ratio of H2SO4 to H2O is 1:4, 25 min) → sealing (water temperature 70 °C, 5 min).

[0191] After the aluminum alloy plates prepared in the above embodiments and comparative examples were respectively processed as above, the yield rate and appearance inspection situation are shown in the following table. Among them, the methods for yield rate and appearance inspection are as follows:

[0192] Yield rate: Number of qualified products / Total production quantity;

[0193] Appearance inspection: "GB / T 19822-2024 Specification for Hard Anodic Oxide Coatings on Aluminum and Aluminum Alloys", the main surface should be fully anodized, the appearance should be uniform, and there should be no areas of peeling, sand holes, or powdering (burning). Visual inspection should be used for batch acceptance of appearance. Color difference means inconsistent appearance uniformity.

[0194] Table 2

[0195]

[0196] Application Example 2

[0197] The aluminum alloy flat ingot prepared in Example 1 was processed in a method similar to that of Application Example 1, with the difference being the process parameters listed in Table 3 below.

[0198] Table 3

[0199]

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

[0201] Table 4

[0202]

[0203] As can be seen from the above, adopting the technical solution of the present invention has the following technical effects: For the alloy slab ingot of this application, by controlling the contents of elements such as Mg, Mn, La, Si, Zn, Cr, etc., and having a smaller average grain size and smaller intermetallic compound size at 1 / 4 of the thickness of the aluminum alloy slab ingot, the alloy composition is uniform, and there is no ring segregation in the cross-section of the aluminum alloy slab ingot. This aluminum alloy slab ingot has good mechanical properties and workability. Using this ingot for the processing of aluminum alloy plate materials, etc., has high quality and yield, and can effectively reduce or even avoid phenomena such as forging cracking and surface color difference of anodized products.

[0204] The above are only optional embodiments of this solution and are not used to limit this solution. For those skilled in the art, this solution can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this solution shall be included within the protection scope of this solution.

[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 their combinations.

[0206] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and values of the components and steps set forth in these embodiments do not limit the scope of this solution. At the same time, it should be understood that for the sake of convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that: Similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0207] In the description of this solution, it should be understood that the orientation or positional relationship indicated by orientation words such as "front, rear, upper, lower, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom", etc. is usually based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing this solution and simplifying the description. Without contrary instructions, these orientation words do not indicate or imply that the device or component referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the protection scope of this solution; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0208] For ease of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above" etc. can be used here to describe the spatial positional relationship of a device or feature shown in the figure with other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation other than the orientation of the device described in the figure. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above..." can include both the orientations of "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations should be made for the spatial relative descriptions used here.

[0209] In addition, it should be noted that using words such as "first", "second", etc. to limit components is only for the convenience of differentiating the corresponding components. Without additional statements, the above words have no special meanings. Therefore, it should not be construed as a limitation on the protection scope of this solution.

Claims

1. An aluminum alloy flat ingot, characterized in that, By mass percentage, the composition of the aluminum alloy slab ingot includes: 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 sum of inevitable impurities ≤ 0.15%, and the balance is Al; At the 1 / 4 thickness of the aluminum alloy slab ingot, the average grain size ≤ 90μm, the maximum size of intermetallic compounds ≤ 60μm, and the average size of intermetallic compounds ≤ 15μm.

2. The aluminum alloy flat ingot according to claim 1, wherein, The width of the aluminum alloy slab ingot ≥ 1000mm; And / or, the solid hydrogen content of the aluminum alloy slab ingot ≤ 0.12ug / g.

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

4. A method for preparing an aluminum alloy flat ingot according to any one of claims 1 to 3, characterized in that, It includes the following steps: Step S1, proportion materials and melt according to the composition of the aluminum alloy slab ingot to obtain an aluminum alloy melt; Step S2, purify the aluminum alloy melt to obtain a purified aluminum alloy melt; the purification treatment includes: subjecting the aluminum alloy melt to bottom degassing treatment in the furnace, on-line double degassing treatment, and double-stage filtration treatment in sequence; Step S3, divert the purified aluminum alloy melt through a diversion bag and perform semi-continuous casting to obtain an aluminum alloy as-cast ingot blank; Step S4, perform homogenization treatment on the aluminum alloy as-cast ingot blank to obtain the aluminum alloy slab ingot; Among them, the width of the aluminum alloy slab ingot is denoted as W0, the thickness of the aluminum alloy slab ingot is denoted as T0, and T0 ≤ W0, the width of the diversion bag is denoted as W1, and the thickness of the diversion bag is denoted 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.

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

6. The method for preparing an aluminum alloy flat ingot according to claim 4 or 5, characterized in that, The shunt bag satisfies at least one of the following conditions: (1) The material of the shunt bag is high silica fiber; (2) The material of the shunt bag is high silica fiber, and the content of silicon oxide in the high silica fiber is 95% - 98%; (3) The continuous heat resistance temperature of the shunt bag > 1000°C; (4) The thickness of the shunt bag material is 0.40mm - 0.48mm; (5) The shunt bag is a rectangular trough - shaped structure; (6) The aluminum liquid penetration rate of the shunt bag ≤ 0.2%; 7. The preparation method of the aluminum alloy flat ingot according to claim 4 or 5, characterized in that The shunt bag satisfies at least one of the following conditions: (1) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the shunt bag; (2) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the shunt bag, and the material of the bottom aluminum outlet is a high silica fiber intertwined mesh with a mesh number of 8 - 10; (3) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the shunt bag, and the material of the bottom aluminum outlet is a high silica fiber intertwined mesh with a thickness of 0.59mm - 0.71mm; (4) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the shunt bag. When 1000mm ≤ W0 < 2000mm, 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 shunt bag. When 1000mm ≤ W0 < 2000mm and T0 ≤ 1000mm, the diameter of the bottom aluminum outlet is 54mm - 56mm; (6) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the shunt bag. When W0 ≥ 2000mm, the diameter of the bottom aluminum outlet is 59mm - 61mm; (7) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the shunt bag. When W0 ≥ 2000mm and T0 ≥ 1000mm, the diameter of the bottom aluminum outlet is 59mm - 61mm; (8) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the shunt bag, and the centers of the bottom aluminum outlets are located on the width center line of the shunt bag; (9) Two circular bottom aluminum outlets are symmetrically arranged on the bottom surface of the shunt bag, the centers of the bottom aluminum outlets are located on the width center line of the shunt bag, and the distance between the center of the bottom aluminum outlet and the symmetry center of the bottom surface of the shunt bag is (0.25 - 0.35) × W1.

8. The method for preparing an aluminum alloy flat ingot according to claim 4 or 5, characterized in that, The shunt bag satisfies at least one of the following conditions: (1) Rectangular small aluminum outlets are respectively arranged on two opposite small side surfaces of the shunt bag; (2) Rectangular small aluminum outlets are respectively arranged on two opposite small side surfaces of the shunt bag. The mesh number of the small aluminum outlet is 8 - 10, and the thickness of the material of the small aluminum outlet is 0.59mm - 0.71mm; (3) Rectangular small aluminum outlets are symmetrically arranged on two opposite small side surfaces of the shunt bag respectively. The width of the small aluminum outlet is T1, and the height is 35 - 45mm; (4)When W0 ≥ 2000 mm or T0 ≥ 1000 mm, two rectangular large aluminum outlets are respectively arranged on two large side faces of the shunt bag that are opposite to each other; (5)When W0 ≥ 2000 mm or T0 ≥ 1000 mm, two rectangular large aluminum outlets are respectively arranged on two large side faces of the shunt bag that are opposite to each other. The mesh number of the large aluminum outlet is 8 - 10 meshes, and the thickness of the material of the large aluminum outlet is 0.59 mm - 0.71 mm; (6)When W0 ≥ 2000 mm or T0 ≥ 1000 mm, two rectangular large aluminum outlets are respectively arranged on two large side faces of the shunt bag that are opposite to each other. The two large aluminum outlets on the same side face are symmetrically arranged with respect to the vertical center line of the large side face, and the large aluminum outlet is (0.1 - 0.12)W1 away from the vertical center line of the large side face; (7)When W0 ≥ 2000 mm or T0 ≥ 1000 mm, two rectangular large aluminum outlets are respectively arranged on two large side faces of the shunt bag that are opposite to each other. The size of the large aluminum outlet is (0.15 - 0.25)W1 × (35 - 45) mm.

9. The method for preparing an aluminum alloy flat ingot according to claim 4 or 5, characterized in that The temperature of the smelting is 720 - 750 °C; And / or, during the smelting process, Mg is added when the temperature reaches 735 - 745 °C; And / or, in the 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 carried out in sequence. The temperature of the primary homogenization is 380 - 400 °C, and the heat preservation time is 6 - 8 h; the temperature of the secondary homogenization is 460 - 480 °C, and the heat preservation time is 20 - 25 h; 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 preparation method of the aluminum alloy flat ingot according to claim 4 or 5, characterized in that, The degassing treatment at the furnace bottom includes: refining for 40 - 50 min through a degassing device at the furnace bottom; The online dual degassing treatment is carried out by an online dual degassing device, where the rotor speed is 230 - 250 r / min, the Ar gas flow rate is 4.0 - 4.5 m 3 / h, and the Cl2 gas flow rate is 0.04 - 0.06 m 3 / h; The double - stage filtration treatment includes filtering successively with a 30 ppi filter plate and a 50 ppi filter plate.

11. A method for preparing an aluminum alloy sheet, characterized in that, It includes the following steps: Step A1, saw - cutting an aluminum alloy ingot to obtain an aluminum alloy slice. The aluminum alloy ingot is the aluminum alloy flat ingot described in any one of claims 1 to 3 or the aluminum alloy flat ingot prepared by the preparation method of the aluminum alloy flat ingot described in any one of claims 4 to 10; Step A2, performing anodic oxidation treatment on the aluminum alloy slice. The anodic oxidation treatment includes: degreasing, water washing, alkali washing, neutralization, oxidation and sealing treatment.

12. The preparation method of the aluminum alloy sheet according to claim 11, characterized in that, 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 neutralization solution used is a nitric acid solution with a mass concentration of 18% - 22%, and the neutralization time is 5 - 8 min; And / or, during the oxidation, the oxidation reagent used is a sulfuric acid solution with a mass concentration of 15% - 20%; And / or, the water temperature for the sealing treatment is 70 - 80 °C, and the time is 5 - 8 min.

13. An aluminum alloy sheet, characterized in that, It is prepared by the preparation method described in claim 11 or 12.

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