Preparation process of high-corrosion-resistance 6XXX aluminum alloy slab ingot

Abstract

The invention discloses a preparation process of a high-corrosion-resistance 6XXX aluminum alloy slab ingot in the technical field of aluminum alloy material production, and the high-corrosion-resistance 6XXX aluminum alloy slab ingot comprises the following components in percentage by mass: 0.75-0.85% of Si, less than or equal to 0.2% of Fe, less than or equal to 0.25% of Cu, 0.1-0.2% of Mn, 1.2-1.3% of Mg, less than or equal to 0.15% of Zn, 0.1-0.15% of Cr, 0.05-0.08% of Er, less than or equal to 0.15% of Ti, less than or equal to 0.05% of single other elements, less than or equal to 0.15% of other elements and the balance of Al; the alloy melt smelting and standing temperature is not higher than 750 DEG C, a launder is baked to 200-400 DEG C, during casting, the melt enters a vacuum and rotary blowing degassing and impurity removal box, a plate type filter box and a tubular filter box in sequence, multi-layer composite aluminum melt purification treatment is carried out, and after an obtained high-quality slab ingot is subjected to subsequent processing treatment, the alloy with the tensile strength larger than or equal to 290 MPa and the tensile strength larger than or equal to 290 MPa can be obtained. The exfoliation corrosion level is not lower than PA level, the intergranular corrosion depth is not higher than 100 [mu] m, and the hydrogen content is not higher than 0.1 ml / (100g. Al).

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy material production technology, specifically to a preparation process for high corrosion-resistant 6XXX aluminum alloy flat ingots. Technical Background

[0002] With the accelerating advancement of the technological revolution and industrial transformation represented by information technology, the semiconductor industry has become one of the important indicators for measuring a country's comprehensive strength in terms of economy, science and technology, and military. Semiconductor manufacturing equipment is the engine and cornerstone of technological iteration in the semiconductor industry. Therefore, the research and development of key materials related to the components of manufacturing equipment has become extremely important. Unlike ordinary aluminum alloys, the performance indicators required for high-quality aluminum alloys used in semiconductor equipment are extremely stringent. For example, the main material used for components such as cavities in semiconductor equipment etching and coating equipment is currently 6061 aluminum alloy. Most of these semiconductor devices have high vacuum or inert atmosphere devices, therefore, this type of aluminum alloy needs to have extremely good machinability and dimensional stability. This is related to the high and uneven distribution of internal stress in the aluminum alloy matrix. In addition, semiconductor equipment needs to be repeatedly purged with highly corrosive gases such as CF4 / O2, NF3, Cl2, SiH4, and WF6 during use. Therefore, the anodic oxide film on the surface of the aluminum alloy is required to be uniform, continuous, and dense, and the density and uniformity of the oxide film are closely related to the quality of the aluminum alloy matrix.

[0003] To obtain aluminum alloy matrix structures that meet stringent requirements, compositional design and casting are crucial methods. The main additive elements in 6-series aluminum alloys are Mg and Si. Mg and Si form the strengthening phase Mg₂Si, and the mechanical properties of the aluminum alloy increase with the increasing solid solubility of Mg₂Si in the aluminum matrix. However, the proportions of Mg and Si need to be strictly controlled; too much or too little will reduce the alloy's corrosion resistance. Studies have shown that adding appropriate amounts of rare earth elements to aluminum alloy melts can reduce alloy defects, improve the alloy microstructure, and enhance the alloy's strength, plasticity, corrosion resistance, and electrical breakdown resistance. This invention designs a process for preparing high-corrosion-resistant and electrical breakdown-resistant aluminum alloy flat ingots for high-end equipment. Summary of the Invention

[0004] The purpose of this invention is to provide a process for preparing high corrosion-resistant and electrical breakdown-resistant aluminum alloy flat ingots, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides a high corrosion-resistant 6XXX aluminum alloy flat ingot, which, by mass percentage, comprises: Si: 0.75-0.85%, Fe≤0.2%, Cu: ≤0.25%, Mn: 0.1-0.2%, Mg: 1.2%-1.3%, Zn≤0.15%, Cr: 0.1-0.15%, Er: 0.05-0.08%, Ti≤0.15%, other elements individually ≤0.05%, the sum of other elements ≤0.15%, and the balance being Al.

[0006] A process for preparing a high corrosion-resistant 6XXX aluminum alloy flat ingot includes the following steps:

[0007] 1) According to the mass fraction, smelt the aluminum alloy: Add aluminum ingots, aluminum-manganese master alloy, aluminum-chromium master alloy, and aluminum-erbium master alloy to the smelting furnace in sequence for smelting; set the smelting temperature at 730℃-750℃. After the materials are completely melted, open the permeable bricks in the furnace, sprinkle in the slag removal agent to remove slag, and perform electromagnetic stirring; when the temperature rises to 730-750℃, press magnesium ingots into the melt and stir.

[0008] 2) Refining: The melt obtained in step 1) is refined twice. In the first refining, argon gas and nanoparticle refining agent are introduced into the melt together using a refining car. In the second refining, argon gas is directly introduced into the melt. During the refining process, all the permeable bricks in the furnace are opened.

[0009] 3) Settling and baking process: The melt obtained in step 2) is settling to allow impurities in the melt to float or sink. At the same time, natural gas is used to bake the casting trough at high temperature, so that the temperature of the trough reaches 200-400℃ before casting.

[0010] 4) Degassing and filtration: The melt obtained in step 3) is purified to obtain a high-purity aluminum melt;

[0011] 5) Casting: The high-purity aluminum melt obtained in step 4) is cast at a speed of 20-40 mm / min and a cooling water flow rate of 1000-1200 L / min.

[0012] 6) Homogenization of flat ingots: The flat ingots obtained in step 5) are homogenized and then rapidly cooled with water mist after being taken out of the furnace;

[0013] 7) Forging; Forging the flat ingot obtained in step 6);

[0014] 8) Inspection: The forgings obtained in step 7) are sampled and inspected.

[0015] Preferably, the electromagnetic stirring in step 1) is performed more than twice.

[0016] Preferably, in step 2), the first refining time is 20 minutes and the second refining time is 10 minutes.

[0017] Preferably, the settling time in step 3) is 30 minutes and the settling temperature is 745-755℃.

[0018] Preferably, the purification process in step 4) specifically involves: passing the melt obtained in step 3) through a flow channel into a vacuum and rotary jet degassing and impurity removal box, a plate filter box, and a tubular filter box for multi-level composite aluminum melt purification treatment, resulting in highly purified aluminum melt.

[0019] Preferably, in step 6), the homogenization temperature is 560℃-570℃, and the temperature is maintained for 12-14 hours.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. By precisely controlling the Mg / Si ratio (Mg: 1.2–1.3%, Si: 0.75–0.85%) and adding 0.05–0.08% Er element, the grains are significantly refined and a stable Al3Er phase is formed, effectively inhibiting corrosion propagation.

[0022] 2. The exfoliation corrosion level reaches PA grade, and the intergranular corrosion depth is only 80–100μm, which is far superior to the control group without Er (PC grade, 110–180μm), meeting the environmental requirements of semiconductor equipment in the presence of highly corrosive gases (such as Cl2, CF4 / O2).

[0023] 3. Employing a two-stage refining process (nano-refining agent + argon) and a triple purification process (vacuum rotary degassing + plate filtration + tubular filtration), the hydrogen content is ≤0.08ml / (100g·Al), which is superior to the industry standard (≤0.1ml). Comparative experiments show that omitting vacuum degassing and tubular filtration (Comparative Example 3) will cause the hydrogen content to rise to 0.15ml, verifying the necessity of the composite purification process.

[0024] 4. The introduction of Cr / Mn elements (Cr: 0.1–0.15%, Mn: 0.1–0.2%) to form a dispersed phase, synergistically increasing the recrystallization temperature with Er; the homogenization process (560–570℃ / 12–14h + water mist cooling) eliminates internal stress, resulting in a tensile strength ≥290MPa after forging (measured 298MPa), which is superior to the high-temperature melting comparison group (Comparative Example 2: 285MPa).

[0025] 5. Strictly control the melting temperature at 730–750℃: to avoid Er element burn-off (Comparative Example 2: 750–780℃ caused corrosion resistance to drop to PB level).

[0026] 6. Baking in the flow tank (200–400℃): Prevents secondary hydrogen absorption and oxide inclusions in the melt, ensures the continuity of the surface oxide film, and improves the dimensional stability of semiconductor vacuum cavity components. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1:

[0029] This invention provides a high corrosion-resistant 6XXX aluminum alloy flat ingot, which, by mass percentage, comprises: Si: 0.75%, Fe: 0.1%, Cu: 0.15%, Mn: 0.1%, Mg: 1.2%, Zn: 0.08%, Cr: 0.1%, Er: 0.05%, Ti: 0.07%, other elements individually ≤0.05%, the total of other elements ≤0.15%, and the balance is Al.

[0030] A process for preparing a high corrosion-resistant 6XXX aluminum alloy flat ingot includes the following steps:

[0031] 1) According to the mass fraction, smelt the aluminum alloy: Add aluminum ingots, aluminum-manganese master alloy, aluminum-chromium master alloy, and aluminum-erbium master alloy to the smelting furnace in sequence for smelting; set the smelting temperature at 730℃-750℃. After the materials are completely melted, open the permeable bricks in the furnace, sprinkle in the slag removal agent to remove slag, and perform electromagnetic stirring at least twice; when the temperature rises to 730-750℃, press magnesium ingots into the melt and stir.

[0032] 2) Refining: The melt obtained in step 1) is first refined using a refining cart, with argon gas and nanoparticle refining agent introduced together for 20 minutes. The second refining uses argon gas directly introduced into the melt for 10 minutes. During the refining process, all permeable bricks inside the furnace are opened.

[0033] 3) Settling and Process Baking: The melt obtained in step 2) is allowed to stand for 30 minutes to allow impurities in the melt to float or sink. The settling temperature is 745-755℃. At the same time, natural gas is used to bake the casting trough at high temperature, so that the temperature of the trough reaches 200-400℃ before casting.

[0034] 4) Degassing and filtration: The melt obtained in step 3) is passed through a flow channel and successively enters a vacuum and rotary jet degassing and impurity removal box, a plate filter box, and a tubular filter box for multi-level composite aluminum melt purification treatment to achieve deep purification of the aluminum melt.

[0035] 5) Casting: The high-purity aluminum melt obtained in step 4) is cast at a speed of 20-40 mm / min and a cooling water flow rate of 1000-1200 L / min.

[0036] 6) Homogenization of flat ingots: The flat ingots obtained in step 5) are homogenized at a temperature of 560℃-570℃ for 12-14 hours, and then rapidly cooled with water mist after being taken out of the furnace.

[0037] 7) Forging; Forging the flat ingot obtained in step 6).

[0038] 8) Inspection: The forgings obtained in step 7) are sampled and inspected.

[0039] Example 2:

[0040] This invention provides a high corrosion-resistant 6XXX aluminum alloy flat ingot, which, by mass percentage, comprises: Si: 0.80%, Fe: 0.15%, Cu: 0.20%, Mn: 0.15%, Mg: 1.25%, Zn: 0.10%, Cr: 0.13%, Er: 0.06%, Ti: 0.10%, other elements individually ≤0.05%, and the total of other elements ≤0.15%, with the balance being Al.

[0041] A process for preparing a high corrosion-resistant 6XXX aluminum alloy flat ingot includes the following steps:

[0042] 1) According to the mass fraction, smelt the aluminum alloy: Add aluminum ingots, aluminum-manganese master alloy, aluminum-chromium master alloy, and aluminum-erbium master alloy to the smelting furnace in sequence for smelting; set the smelting temperature at 730℃-750℃. After the materials are completely melted, open the permeable bricks in the furnace, sprinkle in the slag removal agent to remove slag, and perform electromagnetic stirring at least twice; when the temperature rises to 730-750℃, press magnesium ingots into the melt and stir.

[0043] 2) Refining: The melt obtained in step 1) is first refined using a refining cart, with argon gas and nanoparticle refining agent introduced together for 20 minutes. The second refining uses argon gas directly introduced into the melt for 10 minutes. During the refining process, all permeable bricks inside the furnace are opened.

[0044] 3) Settling and Process Baking: The melt obtained in step 2) is allowed to stand for 30 minutes to allow impurities in the melt to float or sink. The settling temperature is 745-755℃. At the same time, natural gas is used to bake the casting trough at high temperature, so that the temperature of the trough reaches 200-400℃ before casting.

[0045] 4) Degassing and filtration: The melt obtained in step 3) is passed through a flow channel and successively enters a vacuum and rotary jet degassing and impurity removal box, a plate filter box, and a tubular filter box for multi-level composite aluminum melt purification treatment to achieve deep purification of the aluminum melt.

[0046] 5) Casting: The high-purity aluminum melt obtained in step 4) is cast at a speed of 20-40 mm / min and a cooling water flow rate of 1000-1200 L / min.

[0047] 6) Homogenization of flat ingots: The flat ingots obtained in step 5) are homogenized at a temperature of 560℃-570℃ for 12-14 hours, and then rapidly cooled with water mist after being taken out of the furnace.

[0048] 7) Forging; Forging the flat ingot obtained in step 6).

[0049] 8) Inspection: The forgings obtained in step 7) are sampled and inspected.

[0050] Example 3:

[0051] This invention provides a high corrosion-resistant 6XXX aluminum alloy flat ingot, which, by mass percentage, comprises: Si: 0.85%, Fe: 0.2%, Cu: 0.25%, Mn: 0.2%, Mg: 1.3%, Zn: 0.15%, Cr: 0.15%, Er: 0.08%, Ti: 0.15%, other elements individually ≤0.05%, the total of other elements ≤0.15%, and the balance being Al.

[0052] A process for preparing a high corrosion-resistant 6XXX aluminum alloy flat ingot includes the following steps:

[0053] 1) According to the mass fraction, smelt the aluminum alloy: Add aluminum ingots, aluminum-manganese master alloy, aluminum-chromium master alloy, and aluminum-erbium master alloy to the smelting furnace in sequence for smelting; set the smelting temperature at 730℃-750℃. After the materials are completely melted, open the permeable bricks in the furnace, sprinkle in the slag removal agent to remove slag, and perform electromagnetic stirring at least twice; when the temperature rises to 730-750℃, press magnesium ingots into the melt and stir.

[0054] 2) Refining: The melt obtained in step 1) is first refined using a refining cart, with argon gas and nanoparticle refining agent introduced together for 20 minutes. The second refining uses argon gas directly introduced into the melt for 10 minutes. During the refining process, all permeable bricks inside the furnace are opened.

[0055] 3) Settling and Process Baking: The melt obtained in step 2) is allowed to stand for 30 minutes to allow impurities in the melt to float or sink. The settling temperature is 745-755℃. At the same time, natural gas is used to bake the casting trough at high temperature, so that the temperature of the trough reaches 200-400℃ before casting.

[0056] 4) Degassing and filtration: The melt obtained in step 3) is passed through a flow channel and successively enters a vacuum and rotary jet degassing and impurity removal box, a plate filter box, and a tubular filter box for multi-level composite aluminum melt purification treatment to achieve deep purification of the aluminum melt.

[0057] 5) Casting: The high-purity aluminum melt obtained in step 4) is cast at a speed of 20-40 mm / min and a cooling water flow rate of 1000-1200 L / min.

[0058] 6) Homogenization of flat ingots: The flat ingots obtained in step 5) are homogenized at a temperature of 560℃-570℃ for 12-14 hours, and then rapidly cooled with water mist after being taken out of the furnace.

[0059] 7) Forging; Forging the flat ingot obtained in step 6).

[0060] 8) Inspection: The forgings obtained in step 7) are sampled and inspected.

[0061] Comparative Example 1:

[0062] This invention provides a high corrosion-resistant 6XXX aluminum alloy flat ingot, which, by mass percentage, comprises: Si: 0.75%, Fe: 0.1%, Cu: 0.15%, Mn: 0.1%, Mg: 1.2%, Zn: 0.08%, Cr: 0.1%, Er: 0.05%, Ti: 0.07%, other elements individually ≤0.05%, the total of other elements ≤0.15%, and the balance is Al.

[0063] A process for preparing a high corrosion-resistant 6XXX aluminum alloy flat ingot includes the following steps:

[0064] 1) According to the mass fraction, smelt the aluminum alloy: Add aluminum ingots, aluminum-manganese master alloy, aluminum-chromium master alloy, and aluminum-erbium master alloy to the smelting furnace in sequence for smelting; set the smelting temperature at 730℃-750℃. After the materials are completely melted, open the permeable bricks in the furnace, sprinkle in the slag removal agent to remove slag, and perform electromagnetic stirring at least twice; when the temperature rises to 730-750℃, press magnesium ingots into the melt and stir.

[0065] 2) Refining: The melt obtained in step 1) is first refined using a refining cart, with argon gas and nanoparticle refining agent introduced together for 20 minutes. The second refining uses argon gas directly introduced into the melt for 10 minutes. During the refining process, all permeable bricks inside the furnace are opened.

[0066] 3) Settling and Process Baking: The melt obtained in step 2) is allowed to stand for 30 minutes to allow impurities in the melt to float or sink. The settling temperature is 745-755℃. At the same time, natural gas is used to bake the casting trough at high temperature, so that the temperature of the trough reaches 200-400℃ before casting.

[0067] 4) Degassing and filtration: The melt obtained in step 3) is passed through a flow channel and successively enters a vacuum and rotary jet degassing and impurity removal box, a plate filter box, and a tubular filter box for multi-level composite aluminum melt purification treatment to achieve deep purification of the aluminum melt.

[0068] 5) Casting: The high-purity aluminum melt obtained in step 4) is cast at a speed of 20-40 mm / min and a cooling water flow rate of 1000-1200 L / min.

[0069] 6) Homogenization of flat ingots: The flat ingots obtained in step 5) are homogenized at a temperature of 560℃-570℃ for 12-14 hours, and then rapidly cooled with water mist after being taken out of the furnace.

[0070] 7) Forging; Forging the flat ingot obtained in step 6).

[0071] 8) Inspection: The forgings obtained in step 7) are sampled and inspected.

[0072] Comparative Example 2:

[0073] This invention provides a high corrosion-resistant 6XXX aluminum alloy flat ingot, which, by mass percentage, comprises: Si: 0.75%, Fe: 0.1%, Cu: 0.15%, Mn: 0.1%, Mg: 1.2%, Zn: 0.08%, Cr: 0.1%, Er: 0.05%, Ti: 0.07%, other elements individually ≤0.05%, the total of other elements ≤0.15%, and the balance is Al.

[0074] A process for preparing a high corrosion-resistant 6XXX aluminum alloy flat ingot includes the following steps:

[0075] 1) According to the mass fraction, smelt the aluminum alloy: Add aluminum ingots, aluminum-manganese master alloy, aluminum-chromium master alloy, and aluminum-erbium master alloy to the smelting furnace in sequence for smelting; set the smelting temperature at 750-780℃. After the materials are completely melted, open the permeable bricks in the furnace, sprinkle in the slag removal agent to remove slag, and perform electromagnetic stirring at least twice; when the temperature rises to 750-780℃, press magnesium ingots into the melt and stir.

[0076] 2) Refining: The melt obtained in step 1) is first refined using a refining cart, with argon gas and nanoparticle refining agent introduced together for 20 minutes. The second refining uses argon gas directly introduced into the melt for 10 minutes. During the refining process, all permeable bricks inside the furnace are opened.

[0077] 3) Settling and Process Baking: The melt obtained in step 2) is allowed to stand for 30 minutes to allow impurities in the melt to float or sink. The settling temperature is 750-760℃. At the same time, natural gas is used to bake the casting trough at high temperature, so that the temperature of the trough reaches 200-400℃ before casting.

[0078] 4) Degassing and filtration: The melt obtained in step 3) is passed through a flow channel and successively enters a vacuum and rotary jet degassing and impurity removal box, a plate filter box, and a tubular filter box for multi-level composite aluminum melt purification treatment to achieve deep purification of the aluminum melt.

[0079] 5) Casting: The high-purity aluminum melt obtained in step 4) is cast at a speed of 20-40 mm / min and a cooling water flow rate of 1000-1200 L / min.

[0080] 6) Homogenization of flat ingots: The flat ingots obtained in step 5) are homogenized at a temperature of 560℃-570℃ for 12-14 hours, and then rapidly cooled with water mist after being taken out of the furnace.

[0081] 7) Forging; Forging the flat ingot obtained in step 6).

[0082] 8) Inspection: The forgings obtained in step 7) are sampled and inspected.

[0083] Comparative Example 3:

[0084] This invention provides a high corrosion-resistant 6XXX aluminum alloy flat ingot, which, by mass percentage, comprises: Si: 0.75%, Fe: 0.1%, Cu: 0.15%, Mn: 0.1%, Mg: 1.2%, Zn: 0.08%, Cr: 0.1%, Er: 0.05%, Ti: 0.07%, other elements individually ≤0.05%, the total of other elements ≤0.15%, and the balance is Al.

[0085] A process for preparing a high corrosion-resistant 6XXX aluminum alloy flat ingot includes the following steps:

[0086] 1) According to the mass fraction, smelt the aluminum alloy: Add aluminum ingots, aluminum-manganese master alloy, aluminum-chromium master alloy, and aluminum-erbium master alloy to the smelting furnace in sequence for smelting; set the smelting temperature at 730℃-750℃. After the materials are completely melted, open the permeable bricks in the furnace, sprinkle in the slag removal agent to remove slag, and perform electromagnetic stirring at least twice; when the temperature rises to 730-750℃, press magnesium ingots into the melt and stir.

[0087] 2) Refining: The melt obtained in step 1) is first refined using a refining cart, with argon gas and nanoparticle refining agent introduced together for 20 minutes. The second refining uses argon gas directly introduced into the melt for 10 minutes. During the refining process, all permeable bricks inside the furnace are opened.

[0088] 3) Settling and baking process: The melt obtained in step 2) is settling for 30 minutes to allow impurities in the melt to float or sink. The settling temperature is 745-755℃.

[0089] 4) Degassing and filtration: The melt obtained in step 3) is passed through a flow channel and successively enters a rotary jet degassing and impurity removal box and a plate filter box for aluminum melt purification treatment.

[0090] 5) Casting: The high-purity aluminum melt obtained in step 4) is cast at a speed of 20-40 mm / min and a cooling water flow rate of 1000-1200 L / min.

[0091] 6) Homogenization of flat ingots: The flat ingots obtained in step 5) are homogenized at a temperature of 560℃-570℃ for 12-14 hours, and then rapidly cooled with water mist after being taken out of the furnace.

[0092] 7) Forging; Forging the flat ingot obtained in step 6).

[0093] 8) Inspection: The forgings obtained in step 7) are sampled and inspected.

[0094] The difference between Comparative Example 1 and Example 1 is that the alloy formula in Comparative Example 1 did not contain Er element, and the Cu content was controlled at 0.2-0.4%, while the other steps were the same.

[0095] Comparative Example 2 differs from Example 1 in that the melting temperature is increased to 750-780°C and the settling temperature is increased to 750-760°C, while the other steps remain the same.

[0096] In Comparative Example 3, unlike Example 1, the flow channel was not baked, and the degassing and filtration steps only involved a rotary jet degassing and impurity removal box and a plate filter box; the other steps were the same.

[0097] The table below shows the detection results for each embodiment.

[0098] Table 1. Detection Results of Examples

[0099]

[0100] In Example 1, a tensile strength ≥290 MPa and a hydrogen content <0.1 ml / (100g Al) were obtained. Compared with Example 1, Example 2, without the addition of Er and with an increased Cu content, improved the alloy's strength but reduced its corrosion resistance. In Example 3, the melting and static casting temperatures were increased to above 750°C, leading to partial Er burn-off and a reduction in the Al3Er phase content, thus weakening the alloy's corrosion resistance. In Example 4, the lack of ladle baking and the absence of a vacuum degassing filter and tubular filter in the melt resulted in ineffective hydrogen removal from the melt. Experimental results indicate that adding Er and properly controlling the melt temperature in this 6XXX flat ingot alloy helps improve its corrosion resistance.

Claims

1. A high corrosion-resistant 6XXX aluminum alloy flat ingot, characterized in that: By mass percentage, high corrosion-resistant 6XXX aluminum alloy flat ingots contain: Si: 0.75-0.85%, Fe≤0.2%, Cu: ≤0.25%, Mn: 0.1-0.2%, Mg: 1.2%-1.3%, Zn≤0.15%, Cr: 0.1-0.15%, Er: 0.05-0.08%, Ti≤0.15%, other elements individually ≤0.05%, total other elements ≤0.15%, and the balance is Al.

2. The preparation process of a high corrosion-resistant 6XXX aluminum alloy flat ingot according to claim 1, characterized in that: Includes the following steps: 1) According to the mass fraction, smelt the aluminum alloy: Add aluminum ingots, aluminum-manganese master alloy, aluminum-chromium master alloy, and aluminum-erbium master alloy to the smelting furnace in sequence for smelting; set the smelting temperature at 730℃-750℃. After the materials are completely melted, open the permeable bricks in the furnace, sprinkle in the slag removal agent to remove slag, and perform electromagnetic stirring; when the temperature rises to 730-750℃, press magnesium ingots into the melt and stir. 2) Refining: The melt obtained in step 1) is refined twice. In the first refining, argon gas and nanoparticle refining agent are introduced into the melt together using a refining car. In the second refining, argon gas is directly introduced into the melt. During the refining process, all the permeable bricks in the furnace are opened. 3) Settling and baking process: The melt obtained in step 2) is settling to allow impurities in the melt to float or sink. At the same time, natural gas is used to bake the casting trough at high temperature, so that the temperature of the trough reaches 200-400℃ before casting. 4) Degassing and filtration: The melt obtained in step 3) is purified to obtain a high-purity aluminum melt; 5) Casting: The high-purity aluminum melt obtained in step 4) is cast at a speed of 20-40 mm / min and a cooling water flow rate of 1000-1200 L / min. 6) Homogenization of flat ingots: The flat ingots obtained in step 5) are homogenized and then rapidly cooled with water mist after being taken out of the furnace; 7) Forging; Forging the flat ingot obtained in step 6); 8) Inspection: The forgings obtained in step 7) are sampled and inspected.

3. The preparation process of a high corrosion-resistant 6XXX aluminum alloy flat ingot according to claim 2, characterized in that, In step 1), the electromagnetic stirring is performed more than twice.

4. The preparation process of a high corrosion-resistant 6XXX aluminum alloy flat ingot according to claim 2, characterized in that, In step 2), the first refining time is 20 minutes, and the second refining time is 10 minutes.

5. The preparation process of a high corrosion-resistant 6XXX aluminum alloy flat ingot according to claim 2, characterized in that, In step 3), the settling time is 30 minutes and the settling temperature is 745-755℃.

6. The preparation process of a high corrosion-resistant 6XXX aluminum alloy flat ingot according to claim 2, characterized in that, The purification process in step 4) specifically involves passing the melt obtained in step 3) through a flow channel into a vacuum and rotary jet degassing and impurity removal box, a plate filter box, and a tubular filter box for multi-level composite aluminum melt purification treatment, resulting in highly purified aluminum melt.

7. The preparation process of a high corrosion-resistant 6XXX aluminum alloy flat ingot according to claim 2, characterized in that, In step 6), the homogenization temperature is 560℃-570℃, and the temperature is maintained for 12-14 hours.

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