Aluminum alloy material, preparation process and application thereof

Abstract

This invention discloses an aluminum alloy material, its preparation process, and its application, comprising the following steps: A preparation process for an aluminum alloy includes the following steps: S1: Melting and casting the prepared aluminum alloy raw materials into an aluminum alloy ingot; S2: Heating the aluminum alloy ingot at a heating rate of 100-200℃ / min and then performing a first heat treatment; S3: Performing a second heat treatment on the aluminum alloy ingot after the first heat treatment; S4: Performing a third heat treatment on the head and tail of the aluminum alloy ingot after the second heat treatment, wherein the temperature of the tail of the aluminum alloy ingot is set 6-12℃ higher than that of the head. This invention utilizes precise heating design in the aluminum ingot to obtain an aluminum ingot with high solid solubility and no high-temperature precipitates.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy technology, specifically to an aluminum alloy material, its preparation method, and its application. Background Technology

[0002] In the manufacture of 3C structural components, 6-series aluminum alloys are commonly used. To meet the requirements of lightweighting and aesthetics, 6013 or modified 6013 alloys with high alloying elements are increasingly used to improve yield strength. However, high alloy content narrows the production process window, making it prone to insufficient solid solution or overheating, which reduces mechanical properties and appearance quality. Insufficient solid solution leads to a decline in material properties, while overheating products form defects in the extruded material. The root cause of these problems usually lies in the aluminum ingot heating process, which aims to improve the plasticity of the aluminum ingot and ensure the solid solution of the strengthening phase. Traditional heating methods such as gas-fired rapid furnaces, resistance slow furnaces, and induction furnaces are suitable for general extrusion production, but are not ideal for products with small extrusion process windows and high requirements for mechanical properties and appearance quality.

[0003] Therefore, finding a suitable preparation method for these high-requirement alloys to improve product quality and performance is of paramount importance. Summary of the Invention

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes an aluminum alloy material, its preparation process, and its application. This invention utilizes precise heating design in aluminum ingots to obtain aluminum ingots with high solid solubility and no high-temperature precipitates. Combined with subsequent preparation processes, this results in an aluminum alloy material with high strength (yield strength ≥360MPa), excellent anodized transparency, and no linear defects in the oxide film.

[0005] The present invention also proposes an aluminum alloy material as described above.

[0006] This invention also proposes an application of aluminum alloy materials in the field of lightweight industry.

[0007] The inventive concept of this invention is as follows:

[0008] For extrusion, due to the slow cooling during the homogenization process, the strengthening phase in the round ingot precipitates to some extent. If only rapid heating is used to reach the extrusion temperature of the round ingot, the strengthening phase in the ingot cannot be dissolved, and complete solution extrusion cannot be achieved, resulting in reduced mechanical properties and poor oxidation effect of the finished product. If only a slow box furnace is used, the slow heating rate means that the annealing temperature (400-500℃) and the high-temperature precipitation temperature range before reaching the extrusion temperature of the round ingot are occupied for a long time. During this time, the precipitated phase further precipitates. When the number of precipitated phases is large and the particles are large, high-temperature heating for more than 6 hours is required in the slow box furnace, affecting production efficiency. At the same time, slow heating alone cannot achieve temperature graded control at the head and tail of individual castings. As the temperature drops during the extrusion process of high-content alloys, the strengthening phase precipitates, thus affecting the mechanical properties and oxidation effect of the finished product. This invention utilizes precise heating design in aluminum ingots to obtain aluminum ingots with high solid solubility and no high-temperature precipitates. Combined with subsequent preparation processes, it can produce aluminum alloy materials with high strength, excellent anodized transparency, and no stripe defects in the oxide film.

[0009] According to one aspect of the present invention, a process for preparing an aluminum alloy is provided, comprising the following steps:

[0010] S1: Melt and cast the prepared aluminum alloy raw materials into aluminum alloy ingots.

[0011] S2: The aluminum alloy ingot is heated at a rate of 100-200℃ / min and then subjected to the first heat treatment.

[0012] S3: Perform a second heat treatment on the aluminum alloy ingot after the first heat treatment.

[0013] S4: The head and tail of the aluminum alloy ingot after the second heat treatment are subjected to a third heat treatment respectively, and the temperature of the tail of the aluminum alloy ingot is set to be 6 to 12°C higher than that of the head of the aluminum alloy ingot.

[0014] In step S1, the first heat treatment time is within 300 seconds, and the temperature of the first heat treatment is: 80℃ below the alloy solution temperature to 10℃ above the alloy solution temperature.

[0015] In step S2, the second heat treatment time is within 0.5 to 4 hours, and the temperature of the second heat treatment is 20°C below the alloy solution temperature to 30°C above the alloy solution temperature.

[0016] In step S3, the third heat treatment of the head of the aluminum alloy ingot takes place within 300 seconds, and the temperature for this third heat treatment is: 15°C below the alloy solution temperature to 30°C above the alloy solution temperature.

[0017] The third heat treatment time for the tail of the aluminum alloy ingot is within 300 seconds, and the temperature for the third heat treatment of the head of the aluminum alloy ingot is: 10℃ lower than the alloy solution temperature to 40℃ higher than the alloy solution temperature.

[0018] The upper limit of the temperature in all the above heat treatments shall not exceed the solidus temperature of the alloy.

[0019] The embodiments of the first aspect of the present invention have at least the following beneficial effects:

[0020] 1. In step S2, the first heat treatment process avoids the aluminum alloy ingot remaining in the annealing and high-temperature precipitation zone for too long. This prevents the growth of strengthening phases and the large-scale precipitation of high-temperature MnAl6 and CrAl7 phases. If a large number of large-particle strengthening phases precipitate, subsequent heating will result in difficulty in solidification or insufficient solidification, reducing mechanical properties. The precipitated high-temperature MnAl6 and CrAl7 phases cannot be re-dissolved into the aluminum matrix during subsequent heating. These large-particle phases react with the aluminum matrix to form galvanic cells during subsequent anodizing, producing pits after corrosion. Under diffuse reflection, this affects the surface transparency and color after oxidation.

[0021] 2. In step S3, the second heat treatment process ensures the full solid solution of the strengthening phase in the alloy and further spheroidization of the iron phase. Through the combination of steps S2 and S3, the precipitation of micron-sized strengthening phases and high-temperature precipitates is avoided as much as possible. In step S3, the small amount of unavoidable micron-sized strengthening precipitates are fully dissolved again, while the iron phase is spheroidized.

[0022] 3. Step S4 involves gradient heating, primarily used for precise temperature control. To achieve high strength, the solution extrusion process has a narrow window, and the material's deformation resistance is high, making rapid extrusion difficult. When the extrusion speed is slow, the extrusion process is a heat dissipation reaction; as the aluminum alloy ingot advances, the extrusion exit temperature gradually decreases. Therefore, to compensate for the extrusion exit temperature, the temperature at the tail end of the alloy ingot is increased. This achieves high-temperature isothermal extrusion, avoiding the precipitation of micron-level strengthening phases, thus ensuring mechanical properties and the transparency of the appearance after oxidation.

[0023] In some embodiments of the present invention, the following steps are included:

[0024] S1: The prepared aluminum alloy raw materials are melted into liquid aluminum alloy and then cast into aluminum alloy ingots.

[0025] S2: The aluminum alloy ingot is heated to 480-540℃ at a heating rate of 100-200℃ / min and held at that temperature for 300s for the first heat treatment.

[0026] S3: After the first heat treatment, the aluminum alloy ingot is held at 540-560℃ for 0.5-4 hours for a second heat treatment.

[0027] S4: The head of the aluminum alloy ingot after the second heat treatment is subjected to a third heat treatment at 545-562°C and the tail of the aluminum alloy ingot is subjected to a third heat treatment at 550-570°C for 300 seconds. The temperature of the tail of the aluminum alloy ingot is set to be 6-12°C higher than that of the head of the aluminum alloy ingot.

[0028] 1. In step S2, the aluminum ingot is rapidly heated from room temperature to a temperature between 480 and 540°C to avoid prolonged residence time in the 400–480°C annealing and high-temperature precipitate precipitation range. This prevents the growth of strengthening phases and the large-scale precipitation of high-temperature precipitates MnAl6 and CrAl7. If a large number of large-particle strengthening phases precipitate, subsequent heating will result in difficulty in solidification or insufficient solidification, reducing mechanical properties. The precipitated high-temperature precipitates MnAl6 and CrAl7 cannot be re-dissolved into the aluminum matrix during subsequent heating. These large-particle phases form galvanic cells with the aluminum matrix during subsequent anodizing, producing pits after corrosion. Under diffuse reflection, this affects the surface transparency and color after oxidation. In step S3, the heating temperature is the solution temperature of the alloy, and the holding time is sufficient to ensure adequate solidification of the strengthening phases and further spheroidization of the iron phase. By coordinating steps S2 and S3, the precipitation of micron-sized strengthening phases and high-temperature precipitates is minimized. In step S3, the unavoidable small amount of micron-sized strengthening precipitates is fully dissolved again, while the iron phase is spheroidized. Step S4 involves gradient heating, primarily for precise temperature treatment. To achieve high strength, the solution extrusion process window is narrow, and the material's deformation resistance is high, making rapid extrusion difficult. When the extrusion speed is slow, the extrusion process is a heat dissipation reaction, and the extrusion exit temperature gradually decreases as the aluminum alloy ingot advances. Therefore, to compensate for the extrusion exit temperature, the tail temperature of the alloy ingot is increased. This achieves high-temperature isothermal extrusion, avoiding the precipitation of micron-sized strengthening phases, thus ensuring mechanical properties and the transparency of the appearance after oxidation.

[0029] The tail end of an aluminum alloy ingot refers to the part that enters the extrusion press and is held in the ingot cylinder.

[0030] In some embodiments of the present invention, the first heat treatment is performed in an induction furnace 1.

[0031] In some embodiments of the present invention, the second heat treatment is carried out in a slow-speed box furnace 2.

[0032] In some embodiments of the present invention, the third heat treatment is carried out in an induction furnace 3.

[0033] In some embodiments of the present invention, the aluminum alloy ingot includes a casting rod with a length of 500-1000 mm.

[0034] In some embodiments of the present invention, the third heat treatment further includes: extrusion, quenching, stretching and straightening, and aging treatment.

[0035] In some embodiments of the present invention, after the stretching and straightening and before the aging treatment, the material is further subjected to a cutting process.

[0036] In some embodiments of the present invention, the quenching includes water quenching.

[0037] In some embodiments of the present invention, the extrusion includes segmented speed extrusion, wherein the extruder main cylinder advance speed is 2.0 to 5.0 mm / s and the extrusion outlet temperature is 550 to 570°C.

[0038] The above-mentioned control of extrusion speed and extrusion outlet temperature helps to obtain a more uniform grain structure, while ensuring that the material maintains high solid solubility during the extrusion process without overheating, thus avoiding mechanical property defects and anodized appearance defects.

[0039] In some embodiments of the present invention, the stretching deformation is 0.5% to 1.6% during the stretching straightening process.

[0040] The aforementioned stretching deformation ensures that the material's dimensional accuracy does not bend, and at the same time eliminates residual stress inside the material during extrusion, preventing processing deformation caused by stress release during subsequent processing.

[0041] In some embodiments of the present invention, the aging treatment temperature is 160–190°C, and the holding time is 3–20 h.

[0042] The aforementioned aging treatment helps to form nanoscale dispersed precipitates, achieving precipitation strengthening of the material. Simultaneously, within this temperature and time range, the material exhibits optimal corrosion resistance, ensuring a good appearance after anodizing and preventing intergranular corrosion or even film peeling.

[0043] According to two aspects of the present invention, a process for preparing aluminum alloy materials is provided.

[0044] In some embodiments of the present invention, the raw materials for preparing the aluminum alloy material, by weight percentage, include the following components: Si: 0.48%–0.78%, Mg: 0.78%–0.96%, Cu: 0.50%–0.97%, Mn: 0.02%–0.17%, Cr ≤ 0.06%, Fe ≤ 0.13%, Ti: 0.003%–0.02%.

[0045] In some embodiments of the present invention, the raw materials for preparing the aluminum alloy material, by weight percentage, include the following components: Si: 0.48%–0.78%, Mg: 0.78%–0.96%, Cu: 0.50%–0.97%, Mn: 0.02%–0.17%, Cr ≤ 0.06%, Fe ≤ 0.13%, Ti: 0.003%–0.02%, the content of a single impurity element ≤ 0.05%, and the balance being Al.

[0046] The aluminum alloy material in this invention belongs to the 6-series Al-Mg-Si alloy, with Si and Mg being the main alloying elements forming the strengthening phase. As shown in the equilibrium phase diagram, the maximum solid solubility of Mg₂Si in the aluminum matrix is ​​1.85%. When the total Mg₂Si content approaches 1.85%, its solution temperature and solidus temperature are very close, making it difficult to control in extrusion production. If the temperature is too low, the solidification is insufficient, and Mg₂Si cannot function effectively. If the temperature is too high, exceeding the solidus temperature of the material, extrusion cracking will occur. Based on strength requirements, this invention controls Si at 0.48–0.78% and Mg at 0.78–0.96%, resulting in a total Mg₂Si content of 1.23–1.51%, effectively ensuring mass production within the process window.

[0047] In the aluminum alloy material of this invention, the Cu content is controlled at 0.50-0.97% in the alloy composition design. Adding an appropriate amount of Cu forms the CuAl2 phase, significantly improving the material's age-hardening properties. If the Cu content is too high, the color after oxidation will be yellowish and dull, reducing transparency.

[0048] Fe is an impurity element in raw materials and its presence is unavoidable. Simply reducing the Fe content will significantly increase the cost of raw materials. This invention controls the Fe content to ≤0.13%, while simultaneously adding 0.02%–0.17% Mn to promote the spheroidization of needle-like Fe phases, forming a dispersed distribution. Heating the cast rod in a slow-speed box furnace further promotes and improves the Fe phase spheroidization rate, thereby enhancing the anodizing effect.

[0049] To refine the grain size, an appropriate amount of Ti (Ti) grain refiner is added during the alloy casting process. Ti particles are a hard phase; if they aggregate, they can easily embed into the softer aluminum alloy matrix during mechanical polishing, leading to the appearance of lines. In this paper, the Ti content is controlled at 0.0030–0.02%.

[0050] The presence of Cr element tends to result in a matte finish after anodizing; therefore, this invention controls the Cr content to ≤0.06%.

[0051] In some embodiments of the present invention, the excess Si content in the aluminum alloy material is 0.12 to 0.33% by weight, and the excess Si content is Si content - Mg content / 1.732.

[0052] The presence of a certain amount of excess Si in the material, with the total excess Si controlled between 0.12% and 0.33%, allows it to act as nucleation sites for the strengthening precipitate phase during aging treatment. This results in a fine, dispersed, and uniform distribution of the strengthening precipitate phase, thereby enhancing strength. However, if the total excess Si exceeds 0.33%, it will severely reduce the elongation of the extruded profile.

[0053] In some embodiments of the present invention, the yield strength of the aluminum alloy material is ≥360MPa.

[0054] According to three aspects of the present invention, an application of the aforementioned aluminum alloy material in the field of lightweight industry is proposed.

[0055] In some embodiments of the present invention, the lightweight industrial field includes at least one of electronic structural components and structural materials. Attached Figure Description

[0056] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0057] Figure 1 Metallographic image of the final extruded product of Example 1;

[0058] Figure 2 Metallographic image of the final extruded product of Example 2;

[0059] Figure 3 Metallographic image of the final extruded product of Comparative Example 1;

[0060] Figure 4 The image shows the metallographic structure of the final extruded product of Comparative Example 2. Detailed Implementation

[0061] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0062] Example 1

[0063] This embodiment prepares an aluminum alloy material, which is obtained from the following components:

[0064] S1: Si: 0.63%, Mg: 0.82%, Cu: 0.65%, Mn: 0.07%, Ti: 0.0073%, Cr: 0.02%, Fe: 0.08%. In this aluminum alloy material, the content of any single impurity element is ≤0.03%, and the total content of all impurity elements is ≤0.15%. The balance is Al. The prepared aluminum alloy raw materials are added to a melting furnace, mixed uniformly, and then melted into a liquid aluminum alloy. The liquid aluminum alloy is then cast into aluminum alloy ingots.

[0065] S2: Induction furnace 1 heats up, set temperature 520℃, heating rate 160℃ / min; after reaching the set temperature, it is transferred to a slow box furnace within 1 minute.

[0066] S3: Slow-speed box furnace 2 heating, set temperature 550℃; aluminum ingot dwell time 1 hour;

[0067] S4: Induction furnace 3 heating, set gradient heating, head temperature 555℃, tail temperature 565℃. Remove within 1 minute after reaching the set temperature.

[0068] S5: The heated short ingot is subjected to segmented speed extrusion. The main cylinder of the extruder advances at a speed of 2.5 to 3.5 mm / s, and the extrusion outlet temperature is 555 to 565℃.

[0069] S6: The extruded product is cooled by water in the online quenching process to achieve online quenching. The temperature of the aluminum alloy profile entering the quenching zone is 530~555℃, and the temperature exiting the quenching zone is ≦150℃.

[0070] S7: The material after online quenching is subjected to tensile treatment, with a tensile length deformation of 0.7%.

[0071] S8: Cut the stretched material as required;

[0072] S9: The conditions for artificial aging are: heat preservation at 180℃ for 8 hours.

[0073] Example 2

[0074] This embodiment prepares an aluminum alloy material, which is obtained from the following components:

[0075] S1: Si: 0.63%, Mg: 0.82%, Cu: 0.65%, Mn: 0.07%, Ti: 0.0073%, Cr: 0.02%, Fe: 0.08%. In this aluminum alloy material, the content of any single impurity element is ≤0.03%, and the total content of all impurity elements is ≤0.15%. The balance is Al. The prepared aluminum alloy raw materials are added to a melting furnace, mixed uniformly, and then melted into a liquid aluminum alloy. The liquid aluminum alloy is then cast into aluminum alloy ingots.

[0076] S2: Induction furnace 1 heats up, set temperature 540℃, heating speed 170℃ / min; after reaching the set temperature, it switches to slow box furnace within 1 minute.

[0077] S3: Slow-speed box furnace 2 heating, set temperature 560℃; aluminum ingot dwell time 1 hour;

[0078] S4: Induction furnace 3 heating, set gradient heating, head temperature 562℃, tail temperature 570℃, remove within 1 minute after reaching the set temperature.

[0079] S5: The heated short ingot is subjected to segmented speed extrusion. The main cylinder of the extruder advances at a speed of 2.5 to 3.5 mm / s, and the extrusion outlet temperature is 555 to 565℃.

[0080] S6: The extruded product is cooled by water in the online quenching process to achieve online quenching. The temperature of the aluminum alloy profile entering the quenching zone is 530~555℃, and the temperature exiting the quenching zone is ≦150℃.

[0081] S7: The material after online quenching is subjected to tensile treatment, with a tensile length deformation of 0.7%;

[0082] S8: Cut the stretched material as required;

[0083] S9: The conditions for artificial aging are: heat preservation at 180℃ for 8 hours.

[0084] Comparative Example 1

[0085] This comparative example prepared an aluminum alloy material. The difference between this comparative example and Example 1 is that it does not include the first to third heat treatments in Example 1, but instead uses slow furnace heating. The other conditions are the same. The material in this comparative example was prepared from the following components:

[0086] S1: Si: 0.63%, Mg: 0.82%, Cu: 0.65%, Mn: 0.07%, Ti: 0.0073%, Cr: 0.02%, Fe: 0.08%. In the aluminum alloy material, the content of a single impurity element is ≤0.03%, the total content of impurity elements is ≤0.15%, and the balance is Al. The prepared aluminum alloy raw materials are added to the melting furnace, mixed evenly, and melted into liquid aluminum alloy. The liquid aluminum alloy is then cast into aluminum alloy ingots.

[0087] S2: Heat the short ingot under the following conditions: slow furnace heating, set temperature 560℃; the aluminum ingot takes 100 minutes to reach the set temperature from room temperature, and the holding time at 560℃ is 1 hour.

[0088] S3: The heated short ingot is subjected to segmented speed extrusion. The main cylinder of the extruder advances at a speed of 2.5 to 3.5 mm / s, and the extrusion outlet temperature is 555 to 565℃.

[0089] S4: The extruded product is cooled by water in the online system to achieve online quenching;

[0090] S5: The material after online quenching is subjected to tensile treatment, with a tensile length deformation of 0.7%.

[0091] S6: Cut the stretched material as required;

[0092] S7: The conditions for artificial aging are: heat preservation at 180℃ for 8 hours.

[0093] Comparative Example 2

[0094] This comparative example prepared an aluminum alloy material. This comparative example does not include the first to third heat treatments of Example 1, but uses rapid jet furnace heating, with all other conditions remaining the same. It was prepared from the following components:

[0095] S1: Si: 0.63%, Mg: 0.82%, Cu: 0.65%, Mn: 0.07%, Ti: 0.0073%, Cr: 0.02%, Fe: 0.08%. In the aluminum alloy material, the content of a single impurity element is ≤0.03%, the total content of impurity elements is ≤0.15%, and the balance is Al. The prepared aluminum alloy raw materials are added to the melting furnace, mixed evenly, and melted into liquid aluminum alloy. The liquid aluminum alloy is then cast into aluminum alloy ingots.

[0096] S2: Heat the short ingot under the following conditions: rapid injection furnace heating, set temperature 540℃; the aluminum ingot takes 28 minutes to reach the set temperature from room temperature.

[0097] S3: The heated short ingot is subjected to segmented speed extrusion. The main cylinder of the extruder advances at a speed of 2.5 to 3.5 mm / s, and the extrusion outlet temperature is 555 to 565℃.

[0098] S4: The extruded product is cooled by water in the online system to achieve online quenching;

[0099] S5: The material after online quenching is subjected to tensile treatment, with a tensile length deformation of 0.7%.

[0100] S6: Cut the stretched material as required;

[0101] S7: The conditions for artificial aging are: heat preservation at 180℃ for 8 hours.

[0102] Comparative Example 3

[0103] This comparative example prepared an aluminum alloy material. The difference between this comparative example and Example 1 is that the heating rate in step S2 is 80℃ / min, while the other conditions are the same as in Example 1.

[0104] Comparative Example 4

[0105] This comparative example prepared an aluminum alloy material. The difference between this comparative example and Example 1 is that in step S2, the heating temperature is 470°C and the heating rate is 60°C / min. The other conditions are the same as in Example 1.

[0106] Comparative Example 5

[0107] This comparative example prepared an aluminum alloy material. The difference between this comparative example and Example 1 is that the heating temperature in step S3 is 520°C, while the other conditions are the same as in Example 1.

[0108] Comparative Example 6

[0109] This comparative example prepared an aluminum alloy material. The difference between this comparative example and Example 1 is that the heating temperature in step S3 is 570°C, while the other conditions are the same as in Example 1.

[0110] Comparative Example 7

[0111] This comparative example prepared an aluminum alloy material. The difference between this comparative example and Example 1 is that the head of the aluminum alloy ingot was subjected to a third heat treatment at 545°C and the tail of the aluminum alloy ingot was subjected to a heat treatment at 550°C for 60 seconds in step S4. The other conditions were the same as in Example 1.

[0112] Comparative Example 8

[0113] This comparative example prepared an aluminum alloy material. The difference between this comparative example and Example 1 is that the head of the aluminum alloy ingot was subjected to a third heat treatment at 545°C for 60 seconds and the tail of the aluminum alloy ingot was subjected to a heat treatment at 558°C for 60 seconds. The other conditions are the same as those in Example 1.

[0114] Comparative Example 9

[0115] This comparative example prepared an aluminum alloy material. The difference between this comparative example and Example 1 is that the second heat treatment in step S3 is not included, while the other conditions are the same as those in Example 1.

[0116] Test case

[0117] 1. The extruded aluminum alloys obtained in the above embodiments and comparative examples were subjected to the following tests:

[0118] The mechanical properties of the product were tested according to GB / T 228.1-2010 "Metallic materials - Tensile testing - Part 1: Test at room temperature", and the results are shown in Table 1.

[0119] 2. The extruded aluminum alloys obtained in Examples 1-2 and Comparative Examples 1-2 were subjected to microstructural examination. Examination method: The aluminum alloy materials were polished, etched (Kohler reagent, etching for 1 minute), dried, and then examined under a metallographic microscope at 200x magnification.

[0120] Table 1 Performance of Aluminum Alloy Profiles

[0121]

[0122]

[0123] The test results in Table 1 show that:

[0124] Depend on Figure 1 It can be seen that the maximum length of the particles in Example 1 is less than 10 μm, and the average length of the top 10 largest particles is less than 7 μm.

[0125] Depend on Figure 2 It can be seen that the maximum length of the particles in Example 2 is less than 10 μm, and the average length of the top 10 largest particles is less than 7 μm.

[0126] Depend on Figure 3 It can be seen that the particles in Comparative Example 1 are relatively large, with a maximum particle length of 15 μm and an average size of 11 μm for the top 10 largest particles.

[0127] Depend on Figure 4 It can be seen that the particles in Comparative Example 2 are large, with a maximum particle length of 22 μm and an average length of 15 μm for the top 10 largest particles.

[0128] As can be seen from the test results of Example 1 and Comparative Example 3 in Table 1, under the same conditions: the heating rate in step S2 causes the Mn phase to precipitate through the high-temperature precipitation phase interval, resulting in a decrease in the appearance quality of anodized products.

[0129] As can be seen from the test results of Example 1 and Comparative Example 4 in Table 1, under the same conditions: the heating rate in step S2 is slow, and the product stays in the high-temperature precipitation phase region for too long, which increases the precipitation of Mn phase in the high-temperature precipitation phase region, resulting in a decrease in the appearance quality of anodized products.

[0130] As can be seen from the test results of Example 1 and Comparative Example 5 in Table 1, under the same conditions: the heating temperature in step S3 is set at 520℃, which is within the lower limit of the solid solution temperature of the material. The solid solution effect is incomplete, and the unsolidified part shows large particles, which reduces the strength of the product and deteriorates the appearance quality of the anodized product.

[0131] As can be seen from the test results of Example 1 and Comparative Example 6 in Table 1, under the same conditions: the heating temperature in step S3 is set to 570°C. At this temperature, the iron phase and excess silicon undergo a eutectic reaction, which leads to overheating. The overheated products result in tail-like line defects after polishing the anode.

[0132] As can be seen from the test results of Example 1 and Comparative Example 7 in Table 1, under the same conditions: in step S4, the heating temperature is set to the lower limit, and the tail temperature is set to be 5°C higher than the head of the aluminum alloy ingot but 6°C lower, resulting in reduced material strength and a hazy anodized appearance.

[0133] As can be seen from the test results of Example 1 and Comparative Example 8 in Table 1, under the same conditions: the maximum and minimum values ​​of the heating temperature set in step S4 exceed 12°C, resulting in deviations in the solid solubility of the material and large deviations in the transparency of the anodized appearance of the same batch of materials.

[0134] As can be seen from the test results of Example 1 and Comparative Example 9 in Table 1, under the same conditions: the temperature setting at the tail of the ingot in step S3 is too low, resulting in the product extruded from the tail of the ingot having lower strength, and the anodized appearance of this part is hazy.

[0135] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method for preparing an aluminum alloy, characterized in that, Includes the following steps: S1: Melt and cast the prepared aluminum alloy raw materials into aluminum alloy ingots. S2: The aluminum alloy ingot is heated at a rate of 100-200℃ / min and then subjected to the first heat treatment. S3: Perform a second heat treatment on the aluminum alloy ingot after the first heat treatment. S4: The head and tail of the aluminum alloy ingot after the second heat treatment are subjected to a third heat treatment respectively, and the temperature of the tail of the aluminum alloy ingot is set to be 6 to 12°C higher than that of the head of the aluminum alloy ingot. In step S1, the first heat treatment time is within 300 seconds, and the temperature of the first heat treatment is: 80℃ below the alloy solution temperature to 10℃ above the alloy solution temperature. In step S2, the second heat treatment time is within 0.5 to 4 hours, and the temperature of the second heat treatment is 20°C below the alloy solution temperature to 30°C above the alloy solution temperature. In step S3, the third heat treatment of the head of the aluminum alloy ingot takes place within 300 seconds, and the temperature for this third heat treatment is: 15°C below the alloy solution temperature to 30°C above the alloy solution temperature. The third heat treatment time for the tail of the aluminum alloy ingot is within 300 seconds, and the temperature for the third heat treatment of the head of the aluminum alloy ingot is: 10℃ lower than the alloy solution temperature to 40℃ higher than the alloy solution temperature. The upper limit of the temperature in all the above heat treatments shall not exceed the solidus temperature of the alloy; After the third heat treatment, the aluminum alloy ingot is subjected to extrusion, quenching, stretching and straightening and aging treatment. The raw materials for preparing the aluminum alloy include the following components: Si: 0.48%–0.78%, Mg: 0.78%–0.96%, Cu: 0.50%–0.97%, Mn: 0.02%–0.17%, Cr≤0.06%, Fe≤0.13%, Ti: 0.003%–0.02%.

2. The preparation method according to claim 1, characterized in that, Includes the following steps: S1: The prepared aluminum alloy raw materials are melted into liquid aluminum alloy and then cast into aluminum alloy ingots. S2: The aluminum alloy ingot is heated to 480-540℃ at a heating rate of 100-200℃ / min and held at that temperature for 300 seconds for the first heat treatment. S3: After the first heat treatment, the aluminum alloy ingot is held at 540-560℃ for 0.5-4 hours for a second heat treatment. S4: The head of the aluminum alloy ingot after the second heat treatment is subjected to a third heat treatment at 545-562°C and the tail of the aluminum alloy ingot is subjected to a third heat treatment at 550-570°C for 300 seconds. The temperature of the tail of the aluminum alloy ingot is set to be 6-12°C higher than that of the head of the aluminum alloy ingot.

3. The preparation method according to claim 1, characterized in that, In the aforementioned tension straightening, the deformation of the tension length is 0.5% to 1.6%.

4. The preparation method according to claim 1, characterized in that, The aging treatment temperature is 160–190℃, and the holding time is 3–20 hours.

5. An aluminum alloy material, characterized in that, The aluminum alloy material is prepared by the method for preparing aluminum alloy according to any one of claims 1 to 4.

6. The aluminum alloy material according to claim 5, characterized in that, The excess Si content is 0.12-0.33% by weight, and the excess Si content is Si content - Mg content / 1.

732.

7. The aluminum alloy material according to claim 5, characterized in that, The yield strength of the aluminum alloy material is ≥360MPa.

8. The application of the aluminum alloy material according to any one of claims 5 to 7 in the field of lightweight industry.

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