Aluminum-magnesium cast aluminum alloy material for automobile structural parts and preparation method of aluminum-magnesium cast aluminum alloy material

Abstract

The invention discloses an aluminum-magnesium cast aluminum alloy material for an automobile structural part and a preparation method of the aluminum-magnesium cast aluminum alloy material, and belongs to the technical field of aluminum alloys. The influence of the high iron content in the regenerated material on the alloy performance is reduced by adopting a Fe content segmented regulation and control method, when the Fe content is lower than 0.25%, Mn is added and the adding amount of Mn is strictly controlled, so that a needle-shaped Fe phase is converted into a Chinese character or skeleton shape, the splitting of the needle-shaped Fe phase to an alloy aluminum matrix is reduced, the ductility of the aluminum alloy material is ensured, and the service life of the aluminum alloy material is prolonged. When the Fe content is increased to 0.25-0.45%, the regulation and control capability of the Mn element is gradually weakened, and a spherical AlFeSiMnV phase is formed by further adding V, so that the negative influence on aluminum matrix splitting after the Fe content is increased is reduced; and by controlling the content of Si, the problems that the fluidity of the aluminum magnesium alloy is low and the casting performance is not ideal are solved, meanwhile, the forming number of Mg2Si strengthening phases in the alloy is increased, and the performance of the alloy is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloys, and in particular relates to an aluminum-magnesium cast aluminum alloy material for automobile structural parts and a preparation method thereof. Background Art

[0002] The demand for lightweight automobiles and the widespread application of heat-treatment-free integrated die-casting in the automobile industry. At present, the alloys mainly used for automobile structural parts are Al-Si alloys and Al-Mg alloys. Among them, the development of aluminum-silicon alloys that do not require heat treatment and the performance of Al-Si alloys themselves have reached bottlenecks, while Al-Mg alloys have lighter weight and higher performance, becoming another better choice for lightweight automobiles and integrated die-casting.

[0003] In order to meet the requirements of high-quality castings, new alloys are generally used instead of old materials to ensure the performance of Al-Mg alloys. With the decline in the output of primary aluminum and the gradual expiration of the service life of existing aluminum alloy materials, the recycled aluminum industry, which has the characteristics of saving minerals and energy, high economic and social benefits, and sustainable development, has gradually attracted attention. Every year, a huge number of aluminum alloys are scrapped due to the expiration of the service life of industrial products, and compared with primary production, the energy consumed by recycling and reproducing scrap aluminum can save 90%. However, the performance of recycled aluminum materials often decreases due to mixed components and other reasons. At the same time, impurities in recycled aluminum materials will cause the recycled aluminum ingots to absorb air and cause pores; stress concentration will also occur at the impurities, becoming the origin of cracks, reducing the processing performance and service life of recycled aluminum.

[0004] Iron is the most common element in recycled aluminum materials that exceeds the standard content. It is also the impurity element that is most harmful to product performance and is difficult to remove. Since the solubility of iron in aluminum is very low (0.5%), most iron elements exist as intermetallic compounds, among which needle-shaped β-Al5FeSi has the greatest impact on the performance of aluminum alloys. The β-Fe phase seriously breaks the integrity and continuity of the aluminum matrix. Due to its high brittleness and hardness, it becomes the origin of fracture when the aluminum alloy is subjected to stress. For iron elements, common treatment ideas mainly include: regulating iron phase, diluting and removing iron elements. Among them, the treatment method of reducing iron content is relatively backward in industrial application due to excessive energy consumption, low production efficiency, introduction of new inclusions, difficulty in achieving precise control, and high iron content after removal. The treatment method of diluting iron elements still uses original aluminum or high-grade materials, which is relatively expensive. Therefore, regulating the Fe phase is still a common means. At the same time, the prior art proposes a method of regulating the Fe phase using Mn elements, but there is a problem that the regulation ability of Mn elements is gradually weakened.

[0005] Therefore, when using recycled materials to prepare aluminum-magnesium cast aluminum alloy materials, how to solve the problem of gradually weakening regulation ability of Mn element and prepare alloy materials with both high strength and high toughness has become a technical problem that technicians in this field need to solve urgently. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides an aluminum-magnesium cast aluminum alloy material for automobile structural parts and a preparation method thereof.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] The present invention provides an aluminum-magnesium cast aluminum alloy material for automobile structural parts, which comprises the following components by mass percentage:

[0009] Mg 3.6-4.0%, Si 2.5-5.5%, Fe≤0.45%, Mn 0.45-0.55%, V≤0.20%, Zn0-0.95%, Cu 0-0.5%, Sr 0.005-0.015%, Zr 0.10-0.20%, Ti 0.08-0.15%, Ni≤0.05%, Sn≤0.05%, Ca≤0.003%, Na≤0.001%, P≤0.003%, and the balance is Al.

[0010] Preferably, the aluminum-magnesium cast aluminum alloy material for automobile structural parts comprises the following components by mass percentage:

[0011] Mg 3.6-4.0%, Si 2.5-5.5%, Fe≤0.25%, Mn 0.45-0.55%, V≤0.025%, Zn0-0.95%, Cu 0-0.5%, Sr 0.005-0.015%, Zr 0.10-0.20%, Ti 0.08-0.15%, Ni≤0.05%, Sn≤0.05%, Ca≤0.003%, Na≤0.001%, P≤0.003%, and the balance is Al.

[0012] Preferably, the aluminum-magnesium cast aluminum alloy material for automobile structural parts comprises the following components by mass percentage:

[0013] Mg 3.6-4.0%, Si 2.5-5.5%, Fe 0.25-0.45%, Mn 0.45-0.55%, V 0.05-0.20%, Zn 0-0.95%, Cu 0-0.5%, Sr 0.005-0.015%, Zr 0.10-0.20%, Ti 0.08-0.15%, Ni≤0.05%, Sn≤0.05%, Ca≤0.003%, Na≤0.001%, P≤0.003%, and the balance is Al.

[0014] Preferably, the contents of Zn and Cu in the aluminum-magnesium cast aluminum alloy material for automobile structural parts are not both 0.

[0015] The present invention also provides a method for preparing the aluminum-magnesium cast aluminum alloy material for automobile structural parts described in the above technical solution, comprising the following steps:

[0016] (1) melting the aluminum ingot and the recycled material to obtain a molten metal;

[0017] (2) transferring part of the melt obtained in step (1) into an alloy furnace, and leaving the remaining part as a cooling material; adding silicon material and manganese material into the alloy furnace, and after heating, adding aluminum-titanium master alloy, copper material, zinc material, aluminum-vanadium master alloy, and aluminum-strontium master alloy for a second melting, and then adding magnesium material for further melting to obtain an alloy liquid;

[0018] (3) alloying the alloy liquid obtained in step (2), then adding an aluminum-zirconium master alloy for a first refining, adding the cooling material in step (2) after slagging, then adding a refining agent for a second refining, and performing degassing refining after slagging to obtain a refined aluminum melt;

[0019] (4) Casting the refined aluminum melt obtained in step (3) to obtain the aluminum-magnesium cast aluminum alloy material for the automobile structural parts.

[0020] Preferably, in step (1), the first melting temperature is 700-740°C.

[0021] Preferably, in step (2), the second melting temperature is 780-800°C.

[0022] Preferably, in step (3), the alloying temperature is 760-780°C, and the alloying holding time is 45±5min.

[0023] Preferably, in step (3), the temperature of adding the zirconium master alloy and the first refining are both ≥ 760°C; and / or,

[0024] The temperatures for adding the refining agent and the second refining are both 720-740°C.

[0025] Preferably, in step (4), the casting temperature is 720-740°C.

[0026] Compared with the prior art, the present invention has the following advantages and technical effects:

[0027] The present invention adopts a method for segmented regulation of Fe element content to reduce the influence of high iron content in recycled materials on alloy performance. When the Fe element content is lower than 0.25%, by adding Mn element and strictly controlling the added amount, the needle-shaped Fe phase is transformed into Chinese characters or skeletons, the cutting of the alloy aluminum matrix by Mn element is reduced, and the elongation of the aluminum alloy material is guaranteed. When the Fe element content is increased to 0.25-0.45%, the regulation ability of Mn element is gradually weakened. By further adding V element and controlling its content, spherical AlFeSiMnV phase is formed, and the negative influence of the increase of Fe element on the cutting of aluminum matrix is ​​reduced. Furthermore, by controlling the Si content, the problems of low fluidity and unsatisfactory casting performance of aluminum-magnesium alloy are solved, and at the same time, the formation amount of Mg2Si strengthening phase in the alloy is increased, and the performance of the alloy is improved. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with specific implementation methods.

[0030] The embodiment of the present invention provides an aluminum-magnesium cast aluminum alloy material for automobile structural parts, which comprises the following components by mass percentage:

[0031] Mg 3.6-4.0%, Si 2.5-5.5%, Fe≤0.45%, Mn 0.45-0.55%, V≤0.20%, Zn0-0.95%, Cu 0-0.5%, Sr 0.005-0.015%, Zr 0.10-0.20%, Ti 0.08-0.15%, Ni≤0.05%, Sn≤0.05%, Ca≤0.003%, Na≤0.001%, P≤0.003%, and the balance is Al.

[0032] In a preferred embodiment, the aluminum-magnesium cast aluminum alloy material for automobile structural parts includes Mg 3.6-4.0%, more preferably 3.72-3.91%, by mass percentage. Mg in the present invention is the main raw material for preparing the aluminum-magnesium cast aluminum alloy material, which is beneficial to improving the hardness of the aluminum alloy and reducing the density of the aluminum alloy, which is beneficial to obtaining a lighter aluminum alloy and achieving the purpose of lightweighting automobile structural parts.

[0033] In a preferred embodiment, the aluminum-magnesium cast aluminum alloy material for automobile structural parts includes Si 2.5-5.5%, more preferably 2.98-5.04%, by mass percentage. The present invention solves the problem of low fluidity and unsatisfactory casting performance of aluminum-magnesium alloy by controlling the content of Si in the aluminum-magnesium alloy, and at the same time increases the amount of Mg2Si strengthening phase formed in the alloy, thereby improving the performance of the alloy.

[0034] In a preferred embodiment, the aluminum-magnesium cast aluminum alloy material for automotive structural parts includes Fe≤0.45% by mass, and more preferably 0.25-0.45%. The Fe element has always been considered as a major harmful impurity in cast aluminum alloys. This is mainly because as the Fe content increases, a needle-shaped Fe phase with high hardness will be formed in the metallographic structure. Its presence splits the matrix of the aluminum alloy and reduces the mechanical properties of the alloy, especially the toughness. The present invention adopts a method of segmented control of the Fe element content to reduce the influence of the Fe element on the performance of the aluminum alloy and increase the amount of recycled materials used in the preparation process.

[0035] In a preferred embodiment, the aluminum-magnesium cast aluminum alloy material for automobile structural parts includes 0.45-0.55% Mn, more preferably 0.46-0.52% Mn by mass percentage. The present invention adds Mn element and strictly controls its content, so that the needle-shaped Fe phase is transformed into Chinese characters or skeletons, reducing its cutting of the alloy aluminum matrix and ensuring the elongation of the aluminum alloy material. In addition, Fe and Mn elements can improve the mold adhesion performance of the alloy.

[0036] In a preferred embodiment, the aluminum-magnesium casting aluminum alloy material used for the automotive structural parts contains V≤0.20% by mass.

[0037] In a preferred embodiment, when Fe≤0.45%, V≤0.025%, and the V element contained in the aluminum alloy material is introduced from recycled materials.

[0038] In a preferred embodiment, when the Fe content is 0.25-0.45%, V is 0.05-0.20%, and more preferably 0.09-0.20%, at this time, it is necessary to add additional V element to make the V content in the aluminum alloy material 0.05-0.20%. When the Fe content is further increased to 0.25-0.45%, the control ability of the Mn element is gradually weakened. By further adding the V element and controlling its content, a spherical AlFeSiMnV phase is formed, which reduces the negative impact of the increase of the Fe element on the splitting of the aluminum matrix.

[0039] In a preferred embodiment, the aluminum-magnesium cast aluminum alloy material for automobile structural parts includes Zn 0-0.95%, more preferably 0.41-0.55%, by mass percentage.

[0040] In a preferred embodiment, the aluminum-magnesium cast aluminum alloy material for automobile structural parts includes Cu 0-0.5%, more preferably 0.18-0.36%, by mass percentage. The present invention utilizes the solid solution strengthening effect of Cu and Zn elements to form a strengthening phase to improve the performance of the aluminum alloy material.

[0041] In a preferred embodiment, the Zn and Cu contents in the aluminum-magnesium cast aluminum alloy material for automobile structural parts are not simultaneously 0.

[0042] In a preferred embodiment, the aluminum-magnesium cast aluminum alloy material for automobile structural parts includes 0.005-0.015% Sr, more preferably 0.005-0.013% Sr by mass percentage. The addition of Sr element is beneficial to improving the strength of the aluminum alloy material, and can also improve the fluidity and solidification of the alloy, reduce the generation of casting shrinkage cavities and thermal cracks, and improve the density and mechanical properties of the alloy material.

[0043] In a preferred embodiment, the aluminum-magnesium cast aluminum alloy material for automobile structural parts includes 0.10-0.20% Zr, more preferably 0.11-0.17% Zr by mass percentage. Zr element has self-purification ability and can reduce the content of impurity elements in the alloy material.

[0044] In a preferred embodiment, the aluminum-magnesium cast aluminum alloy material for automobile structural parts includes 0.08-0.15% Ti, more preferably 0.09-0.13% Ti by mass percentage. The addition of Ti element can significantly refine the aluminum alloy structure, which is beneficial to improving the strength and toughness of the alloy material.

[0045] In a preferred embodiment, the aluminum-magnesium cast aluminum alloy material for automobile structural parts includes Ni≤0.05%, Sn≤0.05%, Ca≤0.003%, Na≤0.001%, and P≤0.003% by mass percentage. Ni, Sn, Ca, Na, and P are impurity elements, and controlling their contents within the above range is conducive to reducing the adverse effects of each impurity element on the aluminum alloy material.

[0046] In a preferred embodiment, the aluminum-magnesium series casting aluminum alloy material for automobile structural parts further includes a balance of Al in terms of mass percentage.

[0047] The present invention also provides a method for preparing the aluminum-magnesium cast aluminum alloy material for automobile structural parts described in the above technical solution, comprising the following steps:

[0048] (1) melting the aluminum ingot and the recycled material to obtain a molten metal;

[0049] (2) transferring part of the melt obtained in step (1) into an alloy furnace, and leaving the remaining part as a cooling material; adding silicon material and manganese material into the alloy furnace, and after heating, adding aluminum-titanium master alloy, copper material, zinc material, aluminum-vanadium master alloy, and aluminum-strontium master alloy for a second melting, and then adding magnesium material for further melting to obtain an alloy liquid;

[0050] (3) alloying the alloy liquid obtained in step (2), then adding an aluminum-zirconium master alloy for a first refining, adding the cooling material in step (2) after slagging, then adding a refining agent for a second refining, and performing degassing refining after slagging to obtain a refined aluminum melt;

[0051] (4) Casting the refined aluminum melt obtained in step (3) to obtain the aluminum-magnesium cast aluminum alloy material for automobile structural parts.

[0052] The present invention adds aluminum-zirconium master alloy after the main alloy elements are added and alloyed, utilizes the self-purification ability of Zr element to carry out the first refining and slag removal, and then continues to add refining agent after slag removal to carry out the second refining and slag removal. While ensuring that each element in the alloy meets the design requirement range, it also meets the melt purification requirements of increasing non-metallic inclusions and oxidation inclusions in the melt.

[0053] In a preferred embodiment, in step (1), the aluminum ingot is A00.

[0054] In a preferred embodiment, in step (1), the recycled material is an aluminum-magnesium alloy recycled material; the source of the recycled material includes one or more of discarded motorcycle wheels, discarded 5-series aluminum profiles, discarded 6-series aluminum profiles, and discarded automobile radiators; the method of adding the recycled material includes bottom feeding or soaking feeding.

[0055] In a preferred embodiment, in step (1), the first melting temperature is 700-740°C.

[0056] In a preferred embodiment, in step (2), the cooling material is used to adjust the first refining temperature to the second refining temperature, and the amount of the cooling material is controlled according to the temperature difference between the first refining temperature and the second refining temperature; for every 1wt‰ of cooling material added, the temperature decreases by 1°C.

[0057] In a preferred embodiment, in step (2), the silicon material is industrial silicon; the manganese material is electrolytic manganese; the copper material is electrolytic copper; and the zinc material is zinc ingot.

[0058] In a preferred embodiment, in step (2), when the content of Ca in the recycled material exceeds the design requirements, the step of adding a decalcifying agent is also included while adding silicon material and manganese material to the alloy furnace. After adding the recycled material, trace impurity elements, especially Ca element, will inevitably be introduced. When the content of Ca element exceeds the specified requirements, it will have an adverse effect on the performance of the alloy. The present invention removes Ca element impurities by adding a decalcifying agent, thereby avoiding the replacement reaction between Sr element and Ca element in the subsequent preparation process, resulting in a re-increase of Ca element and affecting the performance of the alloy.

[0059] In a preferred embodiment, the decalcifying agent includes K3AlF6; the amount of the decalcifying agent is determined according to the content of Ca in the recycled material, and the Ca in the aluminum-magnesium cast aluminum alloy material for automobile structural parts is controlled to be ≤0.003%. When K3AlF6 is used as the decalcifying agent, adding 25 kg of the decalcifying agent to every 25 t of melt can reduce the Ca content by about 0.0005%.

[0060] In a preferred embodiment, in step (2), the heating is increased to the second melting temperature.

[0061] In a preferred embodiment, in step (2), the magnesium material is a magnesium ingot; and the magnesium material is added by soaking.

[0062] In a preferred embodiment, in step (2), stirring is performed multiple times during the addition of materials to ensure that the materials are completely melted.

[0063] In a preferred embodiment, in step (2), the second melting temperature is 780-800°C.

[0064] In a preferred embodiment, in step (3), the alloying temperature is 760-780°C, and the alloying holding time is 45±5min; during the alloying holding period, at least 3 stirring operations are performed, and each stirring operation lasts no less than 5min.

[0065] In a preferred embodiment, in step (3), the temperature of adding the zirconium master alloy and the first refining are both ≥ 760°C.

[0066] In a preferred embodiment, in step (3), the temperatures for adding the refining agent and the second refining are both 720-740°C.

[0067] In a preferred embodiment, in step (3), the refining agent is a C2Cl6 sodium-free high-efficiency refining agent; the amount of the refining agent used is 0.5-1wt‰ of the total feed amount.

[0068] In a preferred embodiment, in step (3), the degassing and refining gas is nitrogen; and the degassing and refining time is ≥ 20 min.

[0069] In a preferred embodiment, in step (3), the chemical composition and pinhole degree of the refined aluminum melt are tested after degassing and refining, and the pinhole degree is required to be ≤ level 2.

[0070] In a preferred embodiment, in step (4), the casting temperature is 720-740°C.

[0071] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0072] Examples 1 to 6

[0073] A method for preparing aluminum-magnesium cast aluminum alloy material for automobile structural parts:

[0074] (1) Adding A00 and recycled materials into a melting furnace, performing a first melting at 700° C. to obtain a melt; wherein the recycled materials are added as a bottom feed;

[0075] (2) The melt obtained in step (1) is stirred evenly, and then part of the melt is transferred to an alloy furnace, and the remaining part of the melt is reserved as a cooling material (the melt is reserved according to the temperature difference between the first refining temperature and the second refining temperature in step (4)); industrial silicon, electrolytic manganese and K3AlF6 are added to the alloy furnace, the temperature is raised to 780°C, and the Si and Mn contents are detected to see whether they meet the design requirements, and then aluminum-titanium master alloy, electrolytic copper, zinc ingot, aluminum-vanadium master alloy and aluminum-strontium master alloy are added and maintained at 780°C for a second melting. After the above materials are completely melted, magnesium ingots are added by immersion and the melting is continued. During the addition of materials, the materials are stirred several times to finally obtain an alloy liquid.

[0076] (3) The temperature of the alloy liquid obtained in step (2) is adjusted to 760° C. for alloying, and the alloy liquid is kept at this temperature for 45 minutes. During the keeping temperature period, the alloy liquid is stirred three times, each time for not less than 5 minutes, to obtain the alloy liquid.

[0077] (4) adding an aluminum-zirconium master alloy to the alloy liquid obtained in step (3) for a first refining, wherein the addition temperature of the aluminum-zirconium master alloy and the first refining temperature are both 760° C., and after the refining is completed, slag is removed, and then the cooling material in step (2) is added to adjust the temperature to 720° C., and then a C2Cl6 sodium-free high-efficiency refining agent with a total feed amount of 0.5 wt‰ is added for a second refining, and after the refining is completed, slag is removed, and then nitrogen is used for degassing refining, and the degassing refining time is 20 min to obtain a refined aluminum melt and detect the chemical composition and pinhole degree of the refined aluminum melt;

[0078] (5) Casting the refined aluminum melt obtained in step (4) at 720° C. to obtain an aluminum-magnesium cast aluminum alloy material for automobile structural parts.

[0079] The composition of the aluminum-magnesium cast aluminum alloy materials for automobile structural parts of Examples 1 to 6 is shown in Table 1.

[0080] Table 1 Composition of aluminum-magnesium alloy materials for automotive structural parts in Examples 1 to 6 (wt%)

[0081] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Si 2.98 3.44 5.04 3.11 4.95 4.12 Fe 0.19 0.27 0.32 0.18 0.26 0.19 Mg 3.79 3.77 3.88 3.91 3.72 3.82 Zn 0.42 0.009 0.012 0.006 0.41 0.55 Mn 0.52 0.49 0.51 0.52 0.48 0.46 Cu 0.018 0.18 0.22 0.36 0.021 0.019 Ni 0.006 0.011 0.003 0.009 0.002 0.007 Sn 0.009 0.012 0.004 0.011 0.008 0.014 Ti 0.13 0.10 0.11 0.09 0.12 0.12 Sr 0.010 0.013 0.011 0.005 0.013 0.012 V 0.021 0.16 0.11 0.024 0.09 0.025 Zr 0.17 0.14 0.13 0.17 0.11 0.14 Ca 0.0022 0.0017 0.0024 0.0017 0.0019 0.0015 Na 0.0006 0.009 0.0008 0.0006 0.0006 0.008 P 0.0023 0.0019 0.0022 0.0023 0.0019 0.0015

[0082] Note: The italic numbers in the table indicate that the element content is the content of the corresponding element in the recycled material, and the element is not added during the preparation process.

[0083] According to GB / T 228.1-2021 “Tensile test of metallic materials Part 1 Room temperature test method”, the tensile strength, yield strength and elongation of the aluminum-magnesium cast aluminum alloy materials for automotive structural parts in Examples 1 to 6 were tested, and the results are shown in Table 2.

[0084] Table 2 Properties of aluminum-magnesium cast aluminum alloy materials for automotive structural parts provided by Examples 1 to 6

[0085]

[0086] It can be seen from Table 2 that the aluminum-magnesium cast aluminum alloy materials for automobile structural parts provided in Examples 1 to 6 of the present invention have a tensile strength of 288.15 to 308.44 MPa, a yield strength of 152.24 to 162.25 MPa, and an elongation of 11.15 to 15.12%.

[0087] Example 7

[0088] The difference from Example 1 is that the addition ratio of each material in steps (1) to (4) is shown in Table 3, and the remaining steps are the same as Example 1.

[0089] Comparative Example 1 (Original Material Solution)

[0090] The difference from Example 1 is that the addition ratio of each material in steps (1) to (4) is shown in Table 3, and the remaining steps are the same as Example 1.

[0091] The addition ratio of each material and the tax-inclusive material cost in Example 7 and Comparative Example 1 are shown in Table 3.

[0092] Table 3 The proportion of each material added and the tax-inclusive material cost in Example 7 and Comparative Example 1

[0093]

[0094] In the table, the master alloys include aluminum-titanium master alloys, aluminum-vanadium master alloys, aluminum-strontium master alloys and aluminum-zirconium master alloys.

[0095] It can be seen from Table 3 that the use of the scheme of the present invention to prepare aluminum-magnesium cast aluminum alloy materials for automobile structural parts can reuse a large amount of recycled materials, thereby reducing the cost of preparing aluminum alloy materials.

[0096] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An aluminum-magnesium cast aluminum alloy material for automobile structural parts, characterized in that: Calculated by mass percentage, it includes the following components: Mg 3.6-4.0%, Si 2.5-5.5%, Fe≤0.45%, Mn 0.45-0.55%, V≤0.20%, Zn0-0.95%, Cu 0-0.5%, Sr 0.005-0.015%, Zr 0.10-0.20%, Ti 0.08-0.15%, Ni≤0.05%, Sn≤0.05%, Ca≤0.003%, Na≤0.001%, P≤0.003%, and the balance is Al.

2. The aluminum-magnesium cast aluminum alloy material for automobile structural parts according to claim 1, characterized in that: The aluminum-magnesium cast aluminum alloy material for automobile structural parts includes the following components by mass percentage: Mg 3.6-4.0%, Si 2.5-5.5%, Fe≤0.25%, Mn 0.45-0.55%, V≤0.025%, Zn0-0.95%, Cu 0-0.5%, Sr 0.005-0.015%, Zr 0.10-0.20%, Ti 0.08-0.15%, Ni≤0.05%, Sn≤0.05%, Ca≤0.003%, Na≤0.001%, P≤0.003%, and the balance is Al.

3. The aluminum-magnesium cast aluminum alloy material for automobile structural parts according to claim 1, characterized in that: The aluminum-magnesium cast aluminum alloy material for automobile structural parts includes the following components by mass percentage: Mg 3.6-4.0%, Si 2.5-5.5%, Fe 0.25-0.45%, Mn 0.45-0.55%, V 0.05-0.20%, Zn0-0.95%, Cu 0-0.5%, Sr 0.005-0.015%, Zr 0.10-0.20%, Ti 0.08-0.15%, Ni≤0.05%, Sn≤0.05%, Ca≤0.003%, Na≤0.001%, P≤0.003%, and the balance is Al.

4. The aluminum-magnesium cast aluminum alloy material for automobile structural parts according to claim 1, characterized in that: The contents of Zn and Cu in the aluminum-magnesium cast aluminum alloy material for automobile structural parts are not both 0.

5. The method for preparing the aluminum-magnesium cast aluminum alloy material for automobile structural parts according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) melting the aluminum ingot and the recycled material to obtain a molten metal; (2) transferring part of the molten metal obtained in step (1) into an alloy furnace, and leaving the remaining part as cooling material; Add silicon material and manganese material to the alloy furnace, add aluminum-titanium master alloy, copper material, zinc material, aluminum-vanadium master alloy, and aluminum-strontium master alloy after heating for the second melting, and then add magnesium material for further melting to obtain alloy liquid; (3) alloying the alloy liquid obtained in step (2), then adding an aluminum-zirconium master alloy for a first refining, adding the cooling material in step (2) after slagging, then adding a refining agent for a second refining, and performing degassing refining after slagging to obtain a refined aluminum melt; (4) Casting the refined aluminum melt obtained in step (3) to obtain the aluminum-magnesium cast aluminum alloy material for automobile structural parts.

6. The preparation method according to claim 5, characterized in that: In step (1), the first melting temperature is 700-740°C.

7. The preparation method according to claim 5, characterized in that: In step (2), the second melting temperature is 780-800°C.

8. The preparation method according to claim 5, characterized in that: In step (3), the alloying temperature is 760-780°C, and the alloying holding time is 45±5min.

9. The preparation method according to claim 5, characterized in that: In step (3), the temperature of adding the zirconium master alloy and the first refining are both ≥ 760°C; and / or, The temperatures for adding the refining agent and the second refining are both 720-740°C.

10. The preparation method according to claim 5, characterized in that: In step (4), the casting temperature is 720-740°C.

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