Al-Mg-Zn-Zr aluminum alloy round cast ingot and preparation method thereof

Abstract

The invention discloses an Al-Mg-Zn-Zr aluminum alloy round cast ingot and a preparation method thereof, and belongs to the field of aluminum alloys. The invention aims to solve the problem of low yield of cast ingots caused by surface crack defects of the cast ingots. The method comprises the following steps: 1, proportioning according to chemical components, and weighing smelting raw materials; 2, smelting the accurately weighed smelting raw materials in sequence, and adjusting chemical components; and thirdly, the alloy melt with the adjusted chemical components is guided into a heat preservation furnace to be cast, and the aluminum alloy round cast ingot is obtained. According to the method, an existing high-magnesium alloy casting technology is adopted and combined with the scientific proportion of raw materials, technological parameters in the casting process and fine operation in the production process are adjusted according to the influence on cast ingot forming after Zn is added, the cast ingot crack defect is reduced, pure melt is obtained, and the comprehensive finished product rate of cast ingots reaches 84%.

Description

Technical Field

[0001] The invention specifically relates to an Al-Mg-Zn-Zr aluminum alloy round ingot and a preparation method thereof. Background Art

[0002] This alloy is a high-magnesium aluminum alloy containing 7% magnesium. It has high strength and good corrosion resistance. Most of the welding wire materials used for ships have extremely strict requirements on material properties. Traditional high-magnesium alloys such as 5A06 have good corrosion resistance, but the strength cannot meet the requirements of new aluminum alloy hulls. In order to meet welding and processing requirements, Zn and Zr elements are added to the high-magnesium aluminum alloy, and the magnesium content is increased. This can improve its strength, refine the grains and increase the recrystallization temperature.

[0003] However, in the actual production and application process, the alloy faces a series of serious problems. From the perspective of chemical composition and phase composition, although the addition of Zn element improves its strength, it also increases the tendency of casting cracks, making it more difficult to cast and increasing crack scrap. In addition, the addition of trace Zr element increases the tendency of coarse compounds. If the casting temperature is not accurately controlled, the size of the compound will be too large and the flaw detection pass rate will be too low.

[0004] The alloy casting process parameter range is extremely narrow, which means that during the casting process, the adjustable space for process parameters such as temperature, cooling rate, and casting speed is extremely small, and any slight deviation may cause cracks. In actual production, the appearance of cracked scrap not only causes a large amount of raw material waste, but also seriously affects production efficiency and cost control. At the same time, it is difficult to control the purity of the melt, and impurity elements and inclusions are easily mixed into the melt, which not only affects the uniformity and stability of the alloy, but also further aggravates the tendency of cracks. At present, the comprehensive yield rate of ingots is only 52%. Such a low yield rate greatly increases the production cost and limits the large-scale application and promotion of the alloy in industry.

[0005] CN113930648A, the invention name is "A method for preparing a high-zinc aluminum alloy flat ingot", the patent discloses that the high-zinc aluminum alloy flat ingot is composed of Si <0.06%, Fe <0.10%, Cu: 2.3%, Mn <0.10%, Mg: 2.2%, Cr <0.04%, Ni <0.05%, Zn: 6.2%, Ti: 0.017%, Zr: 0.10%, Be: 0.02% and the balance Al in mass percentage. According to the characteristics of different alloying elements, different addition times are selected to ensure that all elements are fully alloyed; the introduction of argon and argon-chlorine mixed gas refining can not only effectively reduce the alkali and alkaline earth metals such as Na, Ca, Li, K in the melt, but also effectively improve the effect of removing impurities and H2 from the melt; the use of online degassing devices can remove H2 in the melt; the use of filtering devices can remove impurities in the melt; the use of adjustable water baffles at the beginning of casting can reduce the cracks in the ingot at the beginning; the selection of reasonable steady-state process parameters can reduce the cracks in the steady-state ingot. The finished product rate of the ingot obtained by the above method can reach more than 90%.

[0006] This patent is for 7 series aluminum alloy, the main additive is Zn, mainly used for aircraft wall panels. This patent is prone to local component segregation during processing. There are performance differences and cracking tendencies caused by uneven composition. The impurity content in the melt is high, and the ingot is prone to defects. Summary of the invention

[0007] The purpose of the present invention is to solve the problem of low ingot yield due to surface crack defects in ingots, and to provide an Al-Mg-Zn-Zr aluminum alloy round ingot and a preparation method thereof.

[0008] The invention discloses an Al-Mg-Zn-Zr aluminum alloy round ingot, which is composed of Si≤0.35%, Fe≤0.35%, Cu≤0.10%, Mn≤0.10%, Mg: 6.0%-7.5%, Cr≤0.05%, Ni≤0.05%, Zn: 0.50%-1.5%, Ti: 0.05-0.15%, Zr: 0.10%-0.30%, Be: 0.0005%-0.005% and the balance Al in terms of mass percentage.

[0009] Furthermore, the Al-Mg-Zn-Zr aluminum alloy round ingot is composed of Si≤0.35%, Fe≤0.35%, Cu≤0.10%, Mn≤0.10%, Mg: 7.0%, Cr≤0.05%, Ni≤0.05%, Zn: 1.0%, Ti: 0.10%, Zr: 0.12%, Be: 0.001% and the balance Al in terms of mass percentage.

[0010] The present invention provides a method for preparing an Al-Mg-Zn-Zr aluminum alloy round ingot, which is carried out in the following manner:

[0011] 1. Ingredients and weighing: according to the proportion of mass percentage Si≤0.35%, Fe≤0.35%, Cu≤0.10%, Mn≤0.10%, Mg: 6.0%-7.5%, Cr≤0.05%, Ni≤0.05%, Zn: 0.50%-1.5%, Ti: 0.05-0.15%, Zr: 0.10%-0.30%, Be: 0.0005%-0.005% and the balance Al, weigh Al99.70 aluminum ingot, metal Mg, metal Zn, AlTi6 master alloy, AlZr3 master alloy, AlBe3 master alloy as smelting raw materials;

[0012] 2. Melting and chemical composition adjustment: first put Al99.70 aluminum ingot into the melting furnace, then add AlZr3 master alloy, wait until the melt temperature reaches 720℃~750℃, add metal Mg, metal Zn, AlTi6 master alloy and AlBe3 master alloy for stirring, the stirring time is not less than 20min, then take samples at 720℃~750℃ for chemical composition analysis, after the chemical composition is qualified, cover with flux to obtain alloy melt;

[0013] 3. Casting: The alloy melt is introduced into a holding furnace at a temperature of 750°C, and an argon-chlorine mixed gas is introduced for refining for not less than 30 minutes, and then allowed to stand for 60 minutes to obtain a refined alloy melt. The refined alloy melt is first passed through an online degassing device, then through a filtering device, and then through a flow plate at a casting speed of 52 mm / min, a melt casting temperature of 730°C, a casting cooling water flow of 72 t / h, a casting water temperature of 24°C, and an online seeding speed of AlTi5B0.2 wire of 1050 mm / min. The melt is injected into a crystallizer for semi-continuous casting to obtain an Al-Mg-Zn-Zr aluminum alloy round ingot.

[0014] In the present invention, Zn is often added to Al alloy as the main alloying element, which can significantly improve the performance of the alloy. Adding Zn and Mg can simultaneously improve the quenching and aging effects, and mainly forms MgZn in the alloy. 2 Strengthening phase. MgZn 2 The solubility of the phase in the alloy decreases sharply with the decrease of temperature, and it has a strong aging hardening ability. In the solid solution range, increasing the content of Zn and Mg can greatly improve the strength.

[0015] Adding Ti to welding wire can improve its mechanical properties, promote the solidification of the weld, improve the corrosion resistance after welding, significantly refine the alloy grains, and reduce the crack tendency of the alloy. Si, Fe, Cr, and Ni are all impurity elements, and the lower their content is in actual production, the better.

[0016] The present invention improves the purity of the melt by performing precise control during the casting process, optimizes the melting and casting process parameters to reduce the crack tendency of the round ingot and solve the surface crack defects of the ingot, thereby improving the ingot flaw detection yield rate and the yield rate of the entire ingot, and at the same time, by adding the Be element to the alloy to reduce the burnout of Mg, making the Mg element more stable, and ultimately achieving the improvement of the performance of the plate after rolling, so as to meet the urgent demand of the industry for high-performance aluminum alloy materials.

[0017] The casting process parameters of the present invention are: casting speed of 52 mm / min, melt casting temperature of 730°C, casting cooling water flow of 72 t / h. The casting process parameters of the patent CN113930648A are: casting speed of 40 mm / min, melt casting temperature of 690-720°C, casting cooling water flow of 80 t / h, and a wiper is used. The process parameters of the two alloys are very different, and the casting process of the patent CN113930648A cannot solve the above problems of the alloy of the present invention.

[0018] In the batching stage, the present invention accurately weighs various raw materials according to specific mass percentages. The content of impurity elements such as Si and Fe is strictly controlled (Si≤0.35%, Fe≤0.35%, actual Si content is 0.10%, Fe content is 0.20%), reducing factors that may cause alloy performance degradation and cracks. At the same time, the proportions of the main alloying elements Mg (6.0%-7.5%) and Zn (0.5%-1.5) are reasonably configured. The reasonable combination of these elements helps to form a stable alloy phase structure and improve the strength of the alloy. The alloy composition of the present invention is the national standard composition 5A33 of GB / T3190-2020, while the CN113930648A patent is a 7050 alloy, and the chemical composition is completely different.

[0019] Trace element addition: Add trace elements such as Zr (0.10%-0.30%) and Ti (0.05-0.15%). Zr and Ti can refine the grain structure of the alloy and make the alloy's structure more uniform. The refined grains can effectively hinder dislocation movement, thereby improving the strength and toughness of the alloy. The Ti element can form a compound with Al as a heterogeneous nucleation core, further refine the grains, and improve the casting properties of the alloy and reduce the generation of cracks.

[0020] The alloy of the present invention has a relatively high Ti content as a welding wire material, which is generally added to 0.10%, while the Ti content of other alloys is mostly less than 0.05%. The Al3Ti particle content of the present invention which adds a high content of Ti as a welding wire material is higher, and the number of aluminum alloy grains generated by the peritectic reaction is more, that is, the nucleation rate of the aluminum alloy grains is improved during the reaction, and the number of generated grains naturally increases, which plays a role in refining the grain structure of the aluminum alloy. The finer the grains, the higher the performance of the aluminum alloy. By adding aluminum alloy refining elements to the welding wire, during the welding process, the added refining elements are transferred to the weld through the welding wire.

[0021] Sequential feeding and stirring: A specific smelting sequence is adopted. First, Al99.70 aluminum ingots are put in, then AlZr3 master alloy. When the melt temperature reaches 720℃~750℃, metal Mg, metal Zn, AlTi6 master alloy and AlBe3 master alloy are added for stirring. The stirring time is not less than 20min. Then, samples are taken and the chemical composition is analyzed at 720℃~750℃. After the chemical composition is qualified, the alloy melt is obtained after covering with flux. This sequential feeding and sufficient stirring method can ensure that various alloy elements are evenly dissolved in the melt and avoid local component segregation. Uniform component distribution helps to form a stable alloy phase structure and reduce performance differences and crack tendency caused by uneven composition. After the chemical composition is qualified, the flux is covered. The main function of the flux is to reduce the oxidation absorption of the melt, which further ensures the purity of the melt.

[0022] This order of adding materials is formulated according to the melting point and different functions of the alloys. It is stipulated in our company's regulations. The comparative documents also use this order of adding materials. If this order of adding materials is not used, there may be uneven composition.

[0023] Temperature and stirring control: Adding metal Mg, metal Zn, AlTi6 master alloy and AlBe3 master alloy at 720-750℃, this process can make these main alloy elements better integrated into the melt, increase the timeliness of refinement, and stirring at the appropriate temperature can control the solidification process of the alloy, which is conducive to the formation of good organizational morphology. Sampling and analyzing the chemical composition can timely discover the component deviation and make adjustments to ensure that the melt composition meets the requirements, thus laying the foundation for the subsequent casting of high-quality ingots. Covering flux can prevent melt oxidation and air absorption, reduce the impurity content in the melt, and improve the purity of the melt, which is very important for reducing defects in ingots and improving the pass rate of flaw detection.

[0024] Refining and standing: The alloy melt is introduced into a holding furnace at a temperature of 750°C, and argon-chlorine mixed gas is introduced for refining for no less than 30 minutes, and then standing for 60 minutes. The refining process can effectively remove the gas and inclusions in the melt, further improving the purity of the melt. Standing can make the inclusions and bubbles in the melt float up, reducing defects such as loose ingots.

[0025] Casting parameter control: After further purifying the melt through the online double degassing device and the filtering device, the melt is injected into the crystallizer for semi-continuous casting under the conditions of specific casting speed (52mm / min), melt casting temperature (730℃), casting cooling water flow (72t / h), casting water temperature (24℃), and online seeding of AlTi5B0.2 wire (speed 1050mm / min). These precise casting parameters can control the solidification rate and cooling rate of the alloy, reduce the generation of thermal stress, and thus reduce the crack tendency of the round ingot. The use of the double degassing device can remove more hydrogen from the melt, and the ingot can reduce the loose defects. The appropriate casting temperature and cooling rate can avoid cracks caused by too fast temperature changes, and the online seeding of AlTi5B0.2 wire can further refine the grains, improve the quality of the ingot, solve the surface crack defects of the ingot, and thus improve the yield of the entire ingot.

[0026] Selection of ingot specifications: round ingots with a diameter of φ405mm are used for casting instead of larger crystallizers. The main consideration is that smaller round ingots can effectively reduce the macro-segregation of chemical composition (Mg element can reduce 5% segregation) and make the composition relatively uniform. If a smaller diameter crystallizer is used for casting, the amount of ingot car and head and tail sawing will increase, thus affecting the improvement of the overall yield rate. Taking all factors into consideration, casting in a crystallizer with a diameter of φ405mm is the best solution.

[0027] Furthermore, the grade of the Al99.70 original aluminum ingot in step 1 is 99.70%, the content of Ti in the AlTi6 master alloy is 6%, the content of Zr in the AlZr3 master alloy is 3%, and the content of Be in the AlBe3 master alloy is 3%.

[0028] Furthermore, the flux in step 2 is composed of 35-40% KCl and 45-55% MgCl by mass. 2 , 5-10% BaCl 2 1~5% NaCl+CaCl 2 Composition: the amount of flux added is 2 kg / ton of melt.

[0029] Furthermore, the argon-chlorine mixed gas in step 3 is composed of 94% argon and 6% chlorine by volume; the purity of argon and chlorine are both 99.999%, and the introduction rate of the argon-chlorine mixed gas is 0.35-0.40 m 3 / min.

[0030] Furthermore, the degassing device in step three is a dual-rotor online degassing device, and two degassing devices are used. The gas in the degassing device is Ar gas with a purity of 99.996%; the filtering device uses a two-stage ceramic filter for filtering, the mesh number of the first-stage ceramic filter is 30ppi, and the mesh number of the second-stage ceramic filter is 50ppi.

[0031] Furthermore, in step three, the Ti content of the online seeded AlTi5B0.2 wire is 5%, and the B content is 0.2%.

[0032] Furthermore, in step three, the shape of the melt injected into the crystallizer is a circle with a diameter of 405 mm.

[0033] Furthermore, the size of the Al-Mg-Zn-Zr aluminum alloy round ingot in step three is φ405mm×6000mm~7000mm.

[0034] Beneficial effects of the present invention:

[0035] The present invention selects different addition times according to the characteristics of different alloys, thereby solving the problem of sufficient alloying of various elements; by adding the element Zn, the performance after rolling can be improved; by adding the element Zr, the grains can be refined and the recrystallization temperature can be increased at the same time; by adding the element Be, the burning loss of the Mg element can be effectively reduced, and the stability of the components can be ensured; by introducing argon-chlorine mixed gas for refining, the alkali and alkaline earth metals such as Na and Ca in the melt can be effectively reduced; the melt flows into a double online degassing device, thereby effectively removing H2 in the melt; and by flowing into a filtering device, the slag can be effectively removed; the yield rate of the ingots obtained according to the above method is improved to 84%, thereby solving the problem of low yield rate of the ingots prepared by the existing method. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The chemical composition detection and physical picture of the Al-Mg-Zn-Zr aluminum alloy round ingot of Example 1;

[0037] Figure 2 This is the chemical composition detection and physical picture of the Al-Mg-Zn-Zr aluminum alloy round ingot of Example 2. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the embodiments of the present invention more clearly understood, the spirit of the contents disclosed by the present invention will be described in detail below. After understanding the embodiments of the contents of the present invention, any technician in the relevant technical field can change and modify them according to the techniques taught by the contents of the present invention without departing from the spirit and scope of the contents of the present invention.

[0039] The exemplary embodiments of the present invention and the description thereof are used to explain the present invention but are not intended to limit the present invention.

[0040] The following examples are used to verify the beneficial effects of the present invention:

[0041] Embodiment 1: A method for preparing an Al-Mg-Zn-Zr aluminum alloy round ingot is completed by the following steps:

[0042] 1. Ingredients and weighing: according to the ratio of mass percentage Si≤0.35%, Fe≤0.35%, Cu≤0.10%, Mn≤0.10%, Mg: 7.0%, Cr≤0.05%, Ni≤0.05%, Zn: 1.0%, Ti: 0.10%, Zr: 0.12%, Be: 0.001% and the balance is Al, weigh Al99.70 aluminum ingot, metal Mg, metal Zn, AlTi6 master alloy, AlZr3 master alloy, AlBe3 master alloy as smelting raw materials;

[0043] 2. Melting and chemical composition adjustment: First put Al99.70 aluminum ingot into the melting furnace, then add AlZr3 master alloy, and when the melt temperature reaches 740℃, add metal Mg, metal Zn, AlTi6 master alloy and AlBe3 master alloy for stirring for 20min, then take samples for chemical composition analysis at 730℃, and after the chemical composition is qualified, cover with flux to obtain alloy melt;

[0044] 3. Casting: The alloy melt is introduced into a holding furnace at a temperature of 750°C, and an argon-chlorine mixed gas is introduced for refining for not less than 30 minutes, and then allowed to stand for 60 minutes to obtain a refined alloy melt. The refined alloy melt is first passed through an online degassing device, then through a filtering device, and then through a flow plate at a casting speed of 52 mm / min, a melt casting temperature of 730°C, a casting cooling water flow of 72 t / h, a casting water temperature of 24°C, and an online seeding speed of AlTi5B0.2 wire of 1050 mm / min. The melt is injected into a crystallizer for semi-continuous casting to obtain an Al-Mg-Zn-Zr aluminum alloy round ingot.

[0045] The Al-Mg-Zn-Zr aluminum alloy round ingot obtained in this embodiment has a qualified chemical composition and no surface defects such as cracks and slag inclusions (such as Figure 1 As shown), the yield rate reached 85%.

[0046] Embodiment 2: A method for preparing an Al-Mg-Zn-Zr aluminum alloy round ingot is completed by the following steps:

[0047] 1. Ingredients and weighing: according to the proportion of mass percentage Si≤0.35%, Fe≤0.35%, Cu≤0.10%, Mn≤0.10%, Mg: 7.10%, Cr≤0.05%, Ni≤0.05%, Zn: 1.10%, Ti: 0.10%, Zr: 0.12%, Be: 0.0011% and the balance is Al, weigh Al99.70 aluminum ingot, metal Mg, metal Zn, AlTi6 master alloy, AlZr3 master alloy, AlBe3 master alloy as smelting raw materials;

[0048] 2. Melting and chemical composition adjustment: First put Al99.70 aluminum ingot into the melting furnace, then add AlZr3 master alloy, and when the melt temperature reaches 740℃, add metal Mg, metal Zn, AlTi6 master alloy and AlBe3 master alloy for stirring for 25min, then take samples for chemical composition analysis at 725℃, and after the chemical composition is qualified, cover with flux to obtain alloy melt;

[0049] 3. Casting: The alloy melt is introduced into a holding furnace at a temperature of 750°C, and an argon-chlorine mixed gas is introduced for refining for not less than 30 minutes, and then allowed to stand for 60 minutes to obtain a refined alloy melt. The refined alloy melt is first passed through an online degassing device, and then through a filtering device, and then through a flow plate at a casting speed of 52 mm / min, a melt casting temperature of 730°C, a casting cooling water flow of 72 t / h, a casting water temperature of 24.3°C, and an online seeding speed of AlTi5B0.2 wire of 1050 mm / min. The melt is injected into a crystallizer for semi-continuous casting to obtain an Al-Mg-Zn-Zr aluminum alloy round ingot.

[0050] The Al-Mg-Zn-Zr aluminum alloy round ingot obtained in this embodiment has a qualified chemical composition and no surface defects such as cracks and slag inclusions (such as Figure 2 As shown), the yield rate reached 84.2%.

Claims

1. An Al-Mg-Zn-Zr aluminum alloy round ingot, characterized in that The Al-Mg-Zn-Zr aluminum alloy round ingot is composed of Si≤0.35%, Fe≤0.35%, Cu≤0.10%, Mn≤0.10%, Mg: 6.0%-7.5%, Cr≤0.05%, Ni≤0.05%, Zn: 0.50%-1.5%, Ti: 0.05-0.15%, Zr: 0.10%-0.30%, Be: 0.0005%-0.005% and the balance Al in terms of mass percentage.

2. The Al-Mg-Zn-Zr aluminum alloy round ingot according to claim 1, characterized in that The Al-Mg-Zn-Zr aluminum alloy round ingot is composed of Si≤0.35%, Fe≤0.35%, Cu≤0.10%, Mn≤0.10%, Mg: 7.0%, Cr≤0.05%, Ni≤0.05%, Zn: 1.0%, Ti: 0.10%, Zr: 0.12%, Be: 0.001% and the balance Al in terms of mass percentage.

3. A method for preparing an Al-Mg-Zn-Zr aluminum alloy round ingot according to claim 1, characterized in that The preparation method is carried out as follows:

1. Ingredients and weighing: according to the proportion of mass percentage Si≤0.35%, Fe≤0.35%, Cu≤0.10%, Mn≤0.10%, Mg: 6.0%-7.5%, Cr≤0.05%, Ni≤0.05%, Zn: 0.50%-1.5%, Ti: 0.05-0.15%, Zr: 0.10%-0.30%, Be: 0.0005%-0.005% and the balance Al, weigh Al99.70 aluminum ingot, metal Mg, metal Zn, AlTi6 master alloy, AlZr3 master alloy, AlBe3 master alloy as smelting raw materials; 2. Melting and chemical composition adjustment: first put Al99.70 aluminum ingot into the melting furnace, then add AlZr3 master alloy, wait until the melt temperature reaches 720℃~750℃, add metal Mg, metal Zn, AlTi6 master alloy and AlBe3 master alloy for stirring, the stirring time is not less than 20min, then take samples at 720℃~750℃ for chemical composition analysis, after the chemical composition is qualified, cover with flux to obtain alloy melt; 3. Casting: The alloy melt is introduced into a holding furnace at a temperature of 750°C, and an argon-chlorine mixed gas is introduced for refining for not less than 30 minutes, and then allowed to stand for 60 minutes to obtain a refined alloy melt. The refined alloy melt is first passed through an online degassing device, then through a filtering device, and then through a flow plate at a casting speed of 52 mm / min, a melt casting temperature of 730°C, a casting cooling water flow of 72 t / h, a casting water temperature of 24°C, and an online seeding speed of AlTi5B0.2 wire of 1050 mm / min. The melt is injected into a crystallizer for semi-continuous casting to obtain an Al-Mg-Zn-Zr aluminum alloy round ingot.

4. The method for preparing an Al-Mg-Zn-Zr aluminum alloy round ingot according to claim 3, characterized in that The grade of the Al99.70 original aluminum ingot described in step 1 is 99.70%, the content of Ti in the AlTi6 master alloy is 6%, the content of Zr in the AlZr3 master alloy is 3%, and the content of Be in the AlBe3 master alloy is 3%.

5. The method for preparing an Al-Mg-Zn-Zr aluminum alloy round ingot according to claim 3, characterized in that The flux in step 2 is composed of 35-40% KCl, 45-55% MgCl2, 5-10% BaCl2, and 1-5% NaCl+CaCl2 by mass percentage, and the amount of flux added is 2 kg / ton of melt.

6. The method for preparing an Al-Mg-Zn-Zr aluminum alloy round ingot according to claim 3, characterized in that The argon-chlorine mixed gas in step 3 is composed of 94% argon and 6% chlorine by volume; the purity of argon and chlorine are both 99.999%, and the introduction rate of the argon-chlorine mixed gas is 0.35-0.40m 3 / min.

7. The method for preparing an Al-Mg-Zn-Zr aluminum alloy round ingot according to claim 3, characterized in that The degassing device described in step three is a dual-rotor online degassing device, and two degassing devices are used. The gas in the degassing device is Ar gas with a purity of 99.996%; the filtering device uses a two-stage ceramic filter for filtering, the mesh number of the first-stage ceramic filter is 30ppi, and the mesh number of the second-stage ceramic filter is 50ppi.

8. The method for preparing an Al-Mg-Zn-Zr aluminum alloy round ingot according to claim 3, characterized in that In step 3, the Ti content of the online seeded AlTi5B0.2 wire is 5%, and the B content is 0.2%.

9. The method for preparing an Al-Mg-Zn-Zr aluminum alloy round ingot according to claim 3, characterized in that In step 3, the shape of the melt injected into the crystallizer is a circle with a diameter of 405 mm.

10. The method for preparing an Al-Mg-Zn-Zr aluminum alloy round ingot according to claim 3, characterized in that The size of the Al-Mg-Zn-Zr aluminum alloy round ingot in step 3 is φ405mm×6000mm~7000mm.

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