Production process of aluminum alloy section

Abstract

The invention provides a production process of an aluminum alloy profile, and belongs to the field of aluminum alloy manufacturing. The process comprises the steps of burdening, smelting and casting, homogenizing treatment, extrusion forming, quenching, stretch straightening and aging treatment. Wherein quenching comprises two stages, in the first stage, liquid nitrogen is used for direct injection for 1-2 seconds; and in the second stage, switching to-55 to-45 DEG C nitrogen atomization for 2-5 seconds. In the first stage, liquid nitrogen is rapidly cooled to form an amorphous / nanocrystalline surface layer, in the second stage, nitrogen atomization controls the size of a beta phase of a core to be smaller than or equal to 50 nm, and through the synergistic effect of burdening, two-stage quenching, two-stage aging and stretching straightening, the technical breakthrough that the tensile strength of the aluminum alloy profile is improved by 16%-25%, the yield strength is improved by 20%-30%, and the corrosion resistance is improved by 70% is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of aluminum alloy manufacturing, and specifically relates to a production process of aluminum alloy profiles. Background Art

[0002] With the booming development of the new energy vehicle market, aluminum alloy has been widely used in new energy vehicles due to its light weight, high strength, corrosion resistance and other characteristics. From the body skeleton to the battery tray, the figure of aluminum alloy profiles can be found everywhere, effectively contributing to the lightweight process of the vehicle and improving the cruising range and energy utilization efficiency of new energy vehicles. Taking a new energy vehicle with a vehicle weight of 1.6t as an example, the amount of aluminum alloy used is about 450kg, accounting for about 30%, which shows its key position in the new energy vehicle material system. In body manufacturing, the body skeleton constructed by high-performance aluminum profiles significantly reduces the body weight while ensuring the structural strength and safety of the body; while the battery tray uses aluminum alloy profiles, which plays a good role in protecting the battery, and its corrosion resistance helps to extend the service life of the battery. However, the current aluminum alloy profiles for new energy vehicles still face many technical challenges. In terms of strength, when the existing aluminum alloy profiles bear complex stresses, the yield strength and tensile strength are difficult to fully meet the increasing high-performance requirements of new energy vehicles, and there is a risk of structural deformation or even failure when encountering high-intensity impacts or long-term heavy loads. At the same time, in the field of corrosion protection, although aluminum alloy itself has certain corrosion resistance, in high-humidity and strong-corrosion environments such as coastal areas and the plum rain season, the surface of automotive cast aluminum parts is extremely easy to be oxidized, showing corrosion phenomena such as "growing white hair". Traditional anti-corrosion processes such as passivation have problems such as high cost, complex processes, and poor compatibility, and it is difficult to fundamentally solve the corrosion hidden danger of aluminum alloy profiles, seriously affecting the service life and safety of new energy vehicles. Summary of the Invention

[0003] In view of the problems existing in the prior art, the present invention aims to provide a production process of aluminum alloy profiles.

[0004] One of the purposes of the present invention is to provide a production process of aluminum alloy profiles, including steps of batching, melting and casting, homogenization treatment, extrusion molding, quenching treatment, stretch straightening and aging treatment; Among them, the quenching treatment includes two stages. In the first stage, liquid nitrogen is directly sprayed for 1-2 seconds; in the second stage, it is switched to nitrogen atomization at -55~-45°C for 2-5 seconds; the cooling rate in the first stage is 5×10 3 ~2×10 4 K / s, and the cooling rate in the second stage is 5×10 2 ~2×10 3 K / s.

[0005] Preferably, the homogenization treatment temperature is 520 - 550 °C and the time is 5 - 10 h.

[0006] Preferably, when extrusion molding, the temperature in the inlet area of the extrusion cylinder is 480 - 500 °C, and the temperature in the die deformation area is 420 - 440 °C.

[0007] Preferably, the extrusion speed in the die deformation area is 8 - 15 mm / s.

[0008] Preferably, the batching is carried out according to the following aluminum alloy components; the aluminum alloy components by weight percentage include: Si 0.6 - 0.65%, Fe ≤ 0.2%, Cu 0.45 - 0.55%, Mn 0.05 - 0.10%, Mg 0.9 - 0.95%, Cr 0.25 - 0.30%, Ni 0.08 - 0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04 - 0.10%, Ce 0.04 - 0.10, and the total of other impurities is not more than 0.15%, and the rest is Al.

[0009] Preferably, stretch straightening is carried out within 10 - 30 minutes after the quenching.

[0010] Preferably, the stretching rate in the stretch straightening step is 0.5% - 2.5%.

[0011] Preferably, the aging treatment includes primary aging treatment and secondary aging treatment; The primary aging treatment includes heat preservation at 110 - 130 °C for 2 - 3 hours; The secondary aging treatment includes heat preservation at 160 - 190 °C for 8 - 10 hours.

[0012] The second object of the present invention is to provide an aluminum alloy profile prepared by the production process of the aluminum alloy profile as described above.

[0013] The third object of the present invention is to provide an application of the aluminum alloy profile as described above in the manufacture of new energy vehicles.

[0014] The beneficial effects of the present invention: The present invention provides a production process for aluminum alloy profiles, including steps of batching, melting and casting, homogenization treatment, extrusion forming, quenching treatment, stretch straightening and aging treatment; wherein, the quenching treatment includes two stages. In the first stage, liquid nitrogen is directly sprayed for 1 - 2 seconds; in the second stage, nitrogen atomization is switched to at - 55~-45°C for 2 - 5 seconds. An amorphous / nanocrystalline mixed surface layer is formed on the surface of the profile at an extremely high cooling rate. The amorphous phase has a structure with short-range order and long-range disorder, and there are no defects such as dislocations. The nanocrystals have small grain sizes. This structure greatly improves the surface hardness and strength, can effectively hinder the movement of dislocations, and thus improves the overall yield strength and tensile strength. The amorphous / nanocrystalline mixed surface layer has a high density and uniformity, no obvious grain boundaries and defects, can effectively block the contact between the external corrosive medium and the matrix, plays a physical shielding role, and improves the corrosion resistance. In the second stage of quenching, nitrogen atomization at - 55~-45°C is used to slowly cool the core, inhibit the precipitation of coarse β-phase, avoid the micro-cell effect formed by the segregation of coarse β-phase at the grain boundaries, reduce the corrosion source, reduce the corrosion sensitivity, and thus improve the corrosion resistance. The fine β-phase (size ≤ 50nm) can be more evenly distributed in the matrix compared with the coarse β-phase, increases the phase interface, hinders the movement of dislocations, and improves the strength of the aluminum alloy.

[0015] The tensile strength of the aluminum alloy profile prepared by the production process of this application reaches 325~350MPa, which is 16%~25% higher than that of the traditional water mist quenching process; the yield strength is 285~310MPa, an increase of 20%~30%, and the corrosion resistance is increased by up to 70%. Specific embodiments

[0016] According to the first aspect of the present invention, a production process for aluminum alloy profiles is provided, including steps of batching, melting and casting, homogenization treatment, extrusion forming, quenching treatment, stretch straightening and aging treatment; wherein, the quenching treatment includes two stages. In the first stage, liquid nitrogen is directly sprayed for 1 - 2 seconds; in the second stage, nitrogen atomization is switched to at - 55~-45°C for 2 - 5 seconds; the cooling rate in the first stage is 5×10 3 ~2×10 4 K / s, and the cooling rate in the second stage is 5×10 2 ~2×10 3 K / s.

[0017] The surface of the profile forms an amorphous / nanocrystalline hybrid surface layer at an extremely high cooling rate. The amorphous phase has a short-range ordered and long-range disordered structure without defects such as dislocations, while the nanocrystalline phase has fine grain sizes. This structure significantly improves the surface hardness and strength, effectively hinders the movement of dislocations, and thus increases the overall yield strength and tensile strength. The amorphous / nanocrystalline hybrid surface layer has a high density and uniformity, without obvious grain boundaries and defects, can effectively block the contact between the external corrosive medium and the matrix, plays a physical shielding role, and improves the corrosion resistance. In the second stage of quenching, nitrogen atomization at -55~-45°C is carried out, and the core is slowly cooled to inhibit the precipitation of coarse β-phase, avoiding the microcell effect formed by the segregation of coarse β-phase at the grain boundaries, reducing the corrosion source, lowering the corrosion sensitivity, and thus improving the corrosion resistance. The fine β-phase (size ≤ 50nm) can be more uniformly distributed in the matrix compared with the coarse β-phase, increasing the phase interface, hindering the movement of dislocations, and improving the strength of the aluminum alloy.

[0018] In the present invention, when the cooling rate in the first stage is lower than 5×10 3 K / s, it may not be possible to achieve a fast enough cooling rate to inhibit the formation and growth of crystal nuclei, making it difficult to form an amorphous phase with a sufficient proportion (the proportion of the amorphous phase ≥ 30%), resulting in the performance of the amorphous / nanocrystalline hybrid surface layer not meeting the requirements. When the cooling rate is higher than 2×10 4 K / s, although it can better promote the formation of the amorphous phase, it may bring excessive thermal stress, resulting in defects such as cracks on the surface of the profile, affecting the quality and performance of the profile.

[0019] If the cooling rate in the second stage is lower than 5×10 2 K / s and the cooling time is too long, it will increase the production cost, and during the long cooling time, coarse β-phase may still precipitate, unable to achieve the purpose of inhibiting coarse β-phase (size ≤ 50nm). When the cooling rate is higher than 2×10 3 K / s, the cooling speed is too fast, the temperature difference between the core and the surface will increase, generating large thermal stress, which may cause the profile to deform or even crack, and is also not conducive to inhibiting the precipitation of coarse β-phase.

[0020] In a preferred embodiment of the present invention, the homogenization treatment temperature is 520~550°C and the time is 5~10h.

[0021] In a preferred embodiment of the present invention, when extrusion molding, the temperature in the inlet area of the extrusion cylinder is 480 - 500°C, and the temperature in the die deformation area is 420 - 440°C.

[0022] In the present invention, when the aluminum alloy is at 480 - 500 °C, it is in a thermoplastic state and the material has good fluidity. Maintaining this temperature range in the inlet area of the extrusion cylinder can make the aluminum alloy billet easier to be extruded into the die, reduce the extrusion pressure, lower the load of the equipment, and at the same time is also conducive to increasing the extrusion speed, thereby improving the production efficiency. For the die deformation area, a temperature of 420 - 440 °C can enable the aluminum alloy to undergo plastic deformation at an appropriate temperature after entering the die, better fill the die cavity, and obtain profiles with high dimensional accuracy and good surface quality. Within this temperature range, the microstructure of the aluminum alloy can be better controlled. During the extrusion process, an appropriate temperature helps to promote the occurrence of dynamic recrystallization, refine the grains of the aluminum alloy, and thus improve the mechanical properties of the aluminum alloy profiles, such as the yield strength and tensile strength. At the same time, such temperature conditions are also beneficial to inhibiting the precipitation of some harmful phases, which is helpful for improving the corrosion resistance of the aluminum alloy.

[0023] When the temperature in the inlet area of the extrusion cylinder exceeds 500 °C, the aluminum alloy may undergo overheating, resulting in coarse grains and a decline in mechanical properties. At the same time, too high a temperature may also cause the alloying elements in the aluminum alloy to burn out or volatilize, affecting the composition and properties of the alloy, and reducing the corrosion resistance of the aluminum alloy profiles. For the die deformation area, a temperature exceeding 440 °C will exacerbate the adhesion phenomenon of the aluminum alloy on the die surface, affecting the surface quality of the profiles, and will accelerate the wear of the die, reducing the service life of the die.

[0024] If the temperature in the inlet area of the extrusion cylinder is lower than 480 °C, the fluidity of the aluminum alloy becomes poor, and the extrusion pressure will increase significantly. This not only requires higher requirements for the extrusion equipment, but may also lead to equipment failures, and at the same time will increase the safety risks during the production process. In the die deformation area, when the temperature is lower than 420 °C, the plastic deformation ability of the aluminum alloy decreases, it is difficult to fill the die cavity, and defects such as material shortage and uneven surface are likely to occur, affecting the dimensional accuracy and appearance quality of the profiles. Too low a temperature is not conducive to the full progress of dynamic recrystallization, the grains of the aluminum alloy cannot be effectively refined, resulting in a reduction in the mechanical properties of the profiles. In addition, low temperature may also cause some phases in the aluminum alloy to precipitate in advance, forming an uneven structure, which has an adverse effect on the corrosion resistance of the profiles.

[0025] In a preferred embodiment of the present invention, the extrusion speed in the die deformation area is 8 - 15 mm / s.

[0026] In the present invention, the extrusion speed in the die deformation zone varies within 8 - 15 mm / s with the temperature in the die deformation zone. This is mainly to achieve the best forming effect and quality of the aluminum alloy profile during the extrusion process under different temperature conditions. When the temperature is relatively low, such as when the temperature in the die deformation zone is around 420 °C, the fluidity of the aluminum alloy material is relatively poor. At this time, if the extrusion speed is too fast, the material will not have enough time to uniformly fill the die cavity, easily causing problems such as surface defects and dimensional deviations, and may also lead to excessive extrusion force, damaging the die and equipment. Therefore, at a lower temperature, a relatively low extrusion speed of about 8 mm / s is selected to allow the material sufficient time to flow and form in the die, ensuring the quality of the profile. At a lower temperature, the deformation resistance of the aluminum alloy is relatively large. If the extrusion speed is too fast, it will cause a large stress concentration inside the material, easily leading to defects in the microstructure, such as too high and uneven dislocation density, cracks, etc., affecting the mechanical properties of the profile. Using a lower extrusion speed helps the microstructure inside the material to change uniformly during the deformation process, gradually introducing appropriate defects such as dislocations, laying a foundation for subsequent heat treatment strengthening.

[0027] As the temperature in the die deformation zone rises to around 440 °C, the fluidity of the aluminum alloy material improves. Appropriately increasing the extrusion speed can, on the one hand, make full use of the good fluidity of the material to improve production efficiency; on the other hand, it can also avoid problems such as overheating and grain growth caused by the material staying in the die for too long due to too slow a speed. Therefore, at a higher temperature, increasing the extrusion speed to about 15 mm / s can improve production efficiency while ensuring the quality of the profile. When the temperature rises, the deformation resistance of the material decreases. Appropriately increasing the extrusion speed can make the aluminum alloy receive appropriate shear force and pressure in the die, promoting the full progress of dynamic recrystallization, making the grains better refined, thereby improving the mechanical properties such as strength and toughness of the profile. At the same time, an appropriate speed can also avoid the precipitation of coarse second phases due to too high a temperature and too long a residence time, which is beneficial to improving the corrosion resistance of the material. Adjusting the extrusion speed according to the temperature in the die deformation zone within the range of 8 - 15 mm / s can comprehensively consider the fluidity and microstructure changes of the aluminum alloy material at different temperatures, achieving the technical purpose of improving the yield strength, tensile strength, and corrosion resistance of the aluminum alloy profile, while ensuring production efficiency and product quality.

[0028] In a preferred embodiment of the present invention, the batching is carried out according to the following aluminum alloy components; the aluminum alloy components by weight percentage include: Si 0.6 - 0.65%, Fe ≤ 0.2%, Cu 0.45 - 0.55%, Mn 0.05 - 0.10%, Mg 0.9 - 0.95%, Cr 0.25 - 0.30%, Ni 0.08 - 0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04 - 0.10%, Ce 0.04 - 0.10%, the total of other impurities is not more than 0.15%, and the rest is Al.

[0029] In the present invention, the precise setting of the composition of the aluminum alloy profile is based on a systematic consideration of the improvement of multi-dimensional properties such as yield strength, tensile strength, and corrosion resistance. As the core element of 6-series aluminum alloys, Si forms Mg2Si strengthening phases in the range of 0.6 - 0.65% in synergy with 0.9 - 0.95% of Mg. During aging treatment, these phases precipitate uniformly in nanoscale sizes, effectively hindering dislocation slip and endowing the alloy with high strength and hardness. If the Si content deviates from this range, too low will result in insufficient strengthening phases, and too high will form coarse silicon phases, weakening toughness and corrosion resistance. Cu is dissolved in the aluminum matrix in a proportion of 0.45 - 0.55%, enhancing strength through solid solution strengthening, and this content can avoid reducing corrosion resistance due to the aggravation of intergranular corrosion tendency.

[0030] Mn plays a role in grain refinement in the range of 0.05 - 0.10% and forms stable compounds with Fe, eliminating the plastic deterioration caused by the hard and brittle phases formed by Fe. When Cr is in the range of 0.25 - 0.30%, it can not only build a dense oxide film on the surface to isolate corrosive media but also improve comprehensive properties by refining grains. Excessive addition will increase the brittleness of the alloy. Ni exists in a trace amount of 0.08 - 0.12%, which can significantly improve high-temperature strength, optimize corrosion resistance and cutting performance at the same time. Too high Ni content will greatly increase costs and may cause performance deterioration.

[0031] Strict control of impurity elements is the key to ensuring performance: the Fe content is limited to ≤ 0.2% to prevent the formation of coarse intermetallic compounds from causing a decrease in plasticity and corrosion resistance; Zn ≤ 0.15% to avoid an increase in stress corrosion sensitivity; Ti ≤ 0.1% to ensure that while refining grains, it will not damage performance due to the formation of coarse TiAl3 phases. La and Ce are added in a proportion of 0.04 - 0.10%, which can not only purify the melt, remove impurity gases, but also optimize the tissue uniformity by refining grains, comprehensively improving strength, toughness, and corrosion resistance. In addition, the total amount of other impurities is controlled within 0.15% to minimize the interference of defects on performance and ensure the stability of the composition. Through the synergistic effect and content optimization of each element, the balance and breakthrough of high strength and excellent corrosion resistance of the aluminum alloy profile are finally achieved.

[0032] In a preferred embodiment of the present invention, stretch straightening is carried out within 10 - 30 minutes after quenching.

[0033] In a preferred embodiment of the present invention, the drawing rate in the stretching and straightening step is 0.5% - 2.5%.

[0034] In the present invention, there are large internal stresses in the quenched aluminum alloy profiles. If not eliminated in time, it will cause problems such as deformation and warping during subsequent processing or use of the profiles. An appropriate drawing rate can cause a certain degree of slip and recombination of the grains inside the profiles, thereby effectively relaxing and eliminating the internal stresses. When the drawing rate is 0.5% - 2.5%, it can better achieve the elimination of internal stresses without changing the basic properties of the profiles. If the drawing rate is too low, such as less than 0.5%, the grains cannot slip sufficiently and the internal stresses are not completely eliminated; while if the drawing rate is too high, exceeding 2.5%, the grains may be overly deformed, resulting in a decline in properties such as the strength and toughness of the profiles. Within this drawing rate range, it helps to further refine the grain structure of the aluminum alloy. During the drawing process, the grains will be elongated along the drawing direction, increasing the grain boundary area, which is beneficial to improving the strength and hardness of the aluminum alloy. At the same time, appropriate drawing can also make the second-phase particles more evenly distributed in the matrix, enhancing the strengthening effect of the second-phase particles, thereby improving the comprehensive mechanical properties of the profiles. If the drawing rate is not appropriate, either the role of refining grains and evenly distributing second-phase particles cannot be fully exerted, or the organizational structure will be damaged due to excessive drawing, affecting the performance. During the production process of aluminum alloy profiles, size deviations and poor straightness may occur. By controlling the drawing rate within 0.5% - 2.5%, precise size adjustment and straightening of the profiles can be carried out. Within this range, the profiles can be uniformly elongated in the length direction, effectively correcting defects such as bending and twisting, improving the size accuracy and straightness of the profiles, and meeting the accuracy requirements of the profiles for different application scenarios. If the drawing rate is too large, it may cause the profiles to be overly elongated, exceeding the dimensional tolerance range; if the drawing rate is too small, the desired straightening effect cannot be achieved, affecting the product quality.

[0035] In a preferred embodiment of the present invention, the two-stage aging treatment includes a primary aging treatment and a secondary aging treatment; The primary aging treatment includes heat preservation at 110 - 130 °C for 2 - 3 hours; The secondary aging treatment includes heat preservation at 160 - 190 °C for 8 - 10 hours.

[0036] In the present invention, heat preservation is carried out at 110 - 130 °C for 2 - 3 hours. The main purpose is to promote the decomposition of supersaturated solid solution in the aluminum alloy, forming a large number of fine and dispersed pre-precipitation phases. At this temperature, atoms have a certain diffusion ability and can slowly aggregate to form some nano-scale precipitation phases coherent with the matrix. These pre-precipitation phases can effectively hinder the movement of dislocations, increase the resistance to dislocation movement, and thus improve the strength of the aluminum alloy. Subsequently, the secondary aging treatment at 160 - 190 °C for 8 - 10 hours. The higher temperature accelerates the atomic diffusion rate, and the pre-precipitation phases further grow and transform into more stable precipitation phases. The size and distribution of these precipitation phases are more uniform and reasonable, and the coherent relationship with the matrix is maintained or optimized, thereby producing a stronger precipitation strengthening effect. At this time, the strengthening effect of the precipitation phases reaches the best state, which can maximize the yield strength and tensile strength of the aluminum alloy.

[0037] The primary aging treatment at a lower temperature helps to form a relatively dense oxide film on the surface of the aluminum alloy. During the heat preservation process at 110 - 130 °C, some alloying elements in the alloy (such as Cr, Mn, etc.) will be enriched on the surface and combine with oxygen to form stable oxides. These oxides can fill the pores of the oxide film, improve the density of the oxide film, and thus prevent the contact between the external corrosive medium and the aluminum alloy matrix, improving the corrosion resistance. The secondary aging treatment at 160 - 190 °C further optimizes the structure and performance of the oxide film. The high temperature repairs some defects in the oxide film and promotes the formation and transformation of some compounds in the oxide film, making the oxide film more stable and firm. In addition, the secondary aging treatment can also make the internal structure of the alloy more uniform, reduce the corrosion tendency caused by non-uniform structure, and further improve the corrosion resistance of the aluminum alloy profile.

[0038] Through the synergistic effect of the primary aging treatment and the secondary aging treatment, the aluminum alloy profile not only obtains high strength but also has good corrosion resistance, meeting the strict requirements of different engineering applications for the performance of aluminum alloys. In addition, the synergistic effect of two-stage quenching and double-stage aging treatment enables the uniform precipitation of Mg2Si strengthening phases, significantly increasing the resistance to dislocation movement, and realizing the superimposed effect of precipitation strengthening and fine grain strengthening.

[0039] In the present invention, the production process of the aluminum alloy profile specifically includes steps of batching, melting and casting, homogenization treatment, extrusion forming, quenching, stretch straightening, and aging treatment; Batching is carried out according to the following aluminum alloy composition: Si 0.6 - 0.65%, Fe ≤ 0.2%, Cu 0.45 - 0.55%, Mn 0.05 - 0.10%, Mg 0.9 - 0.95%, Cr 0.25 - 0.30%, Ni 0.08 - 0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04 - 0.10%, Ce 0.04 - 0.10%, the total of other impurities is not more than 0.15%, and the rest is Al; Batch materials according to the optimized aluminum alloy composition, obtain the casting rod after melting and casting and homogenization treatment at a temperature of 520 - 550 °C for 5 - 10 h. The casting rod is first subjected to extrusion forming treatment. When extrusion forming, the temperature in the inlet area of the extrusion cylinder is 480 - 500 °C, the temperature in the die deformation area is 420 - 440 °C, and the extrusion speed in the die deformation area is 8 - 15 mm / s; then it is subjected to quenching treatment in two stages. In the first stage, liquid nitrogen is directly sprayed for 1 - 2 seconds, and the cooling rate is 5×10 3 ~2×10 4 K / s; in the second stage, it is switched to nitrogen atomization at - 55 - - 45 °C for 2 - 5 seconds, and the cooling rate is 5×10 2 ~2×10 3 K / s; after quenching, stretching straightening and two - stage aging treatment are carried out within 10 - 30 minutes. The stretching rate in the stretching straightening step is 0.5% - 2.5%; the two - stage aging treatment includes primary aging treatment and secondary aging treatment; the primary aging treatment includes heat preservation at 110 - 130 °C for 2 - 3 hours; the secondary aging includes heat preservation at 160 - 190 °C for 8 - 10 hours, and finally the aluminum alloy profile is obtained.

[0040] According to the second aspect of the present invention, there is provided an aluminum alloy profile prepared by the production process of the aluminum alloy profile as described above.

[0041] According to the third aspect of the present invention, there is provided an application of the aluminum alloy profile as described above in the manufacture of new energy vehicles.

[0042] The preferred embodiments of the present invention will be described in detail below.

[0043] Example 1 The production process of the aluminum alloy profile in this example includes steps of batching, melting and casting, homogenization treatment, extrusion forming, quenching, stretching straightening and aging treatment; Batch materials according to the following aluminum alloy composition: Si 0.6 - 0.65%, Fe ≤ 0.2%, Cu 0.45 - 0.55%, Mn 0.05 - 0.10%, Mg 0.9 - 0.95%, Cr 0.25 - 0.30%, Ni 0.08 - 0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04 - 0.10%, Ce 0.04 - 0.10, the total of other impurities is not more than 0.15%, and the rest is Al.

[0044] Batch the materials according to the optimized aluminum alloy composition. After melting, casting and homogenization treatment, a casting rod is obtained. The casting rod is first subjected to extrusion forming. When extrusion forming, the temperature of the inlet area of the extrusion cylinder is 480 °C, the temperature of the die deformation area is 420 °C, and the extrusion speed in the die deformation area is 8 mm / s. Then, it undergoes quenching treatment in two stages. In the first stage, liquid nitrogen is directly sprayed for 2 seconds, and the cooling rate is 5×10 3 K / s; in the second stage, it is switched to nitrogen atomization at -50 °C for 5 seconds, and the cooling rate is 5×10 2 K / s. After quenching, stretching straightening and two-stage aging treatment are carried out within 20 minutes. The stretching rate in the stretching straightening step is 1.5%; the two-stage aging treatment includes primary aging treatment and secondary aging treatment; the primary aging treatment includes heat preservation at 120 °C for 2 hours; the secondary aging includes heat preservation at 180 °C for 10 hours, and finally an aluminum alloy profile is obtained.

[0045] Example 2 The production process of the aluminum alloy profile in this example includes steps of batching, melting and casting, homogenization treatment, extrusion forming, quenching, stretching straightening and aging treatment; Batch the materials according to the following aluminum alloy composition: Si 0.6 - 0.65%, Fe ≤ 0.2%, Cu 0.45 - 0.55%, Mn 0.05 - 0.10%, Mg 0.9 - 0.95%, Cr 0.25 - 0.30%, Ni 0.08 - 0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04 - 0.10%, Ce 0.04 - 0.10, the total of other impurities is not more than 0.15%, and the rest is Al.

[0046] Batch the materials according to the optimized aluminum alloy composition. After melting, casting and homogenization treatment, a casting rod is obtained. The casting rod is first subjected to extrusion forming. When extrusion forming, the temperature of the inlet area of the extrusion cylinder is 480 °C, the temperature of the die deformation area is 420 °C, and the extrusion speed in the die deformation area is 8 mm / s. Then, it undergoes quenching treatment in two stages. In the first stage, liquid nitrogen is directly sprayed for 2 seconds, and the cooling rate is 5×10 3 K / s; in the second stage, it is switched to nitrogen atomization at -55 to -45 °C for 4 seconds, and the cooling rate is 8×10 2K / s; After quenching, stretching straightening and two-stage aging treatment are carried out within 20 minutes. The stretching rate in the stretching straightening step is 1.5%; The two-stage aging treatment includes primary aging treatment and secondary aging treatment; The primary aging treatment includes heat preservation at 120 °C for 2 hours; The secondary aging includes heat preservation at 180 °C for 10 hours, and finally an aluminum alloy profile is obtained.

[0047] Example 3 The production process of the aluminum alloy profile in this example includes steps of batching, melting and casting, homogenization treatment, extrusion molding, quenching, stretching straightening and aging treatment; Batching is carried out according to the following aluminum alloy composition: Si 0.6~0.65%, Fe ≤ 0.2%, Cu 0.45~0.55%, Mn 0.05~0.10%, Mg 0.9~0.95%, Cr 0.25~0.30%, Ni 0.08~0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04~0.10%, Ce 0.04~0.10, and the total of other impurities is not more than 0.15%, and the rest is Al.

[0048] Batching is carried out according to the optimized aluminum alloy composition. After melting and casting and homogenization treatment, a cast rod is obtained. The cast rod is first subjected to extrusion molding treatment. When extrusion molding, the temperature in the inlet area of the extrusion cylinder is 480 °C, the temperature in the die deformation area is 420 °C, and the extrusion speed in the die deformation area is 8 mm / s; Then it undergoes two-stage quenching treatment. In the first stage, liquid nitrogen is directly sprayed for 2 seconds, and the cooling rate is 5×10 3 K / s; In the second stage, it is switched to nitrogen atomization at -55~-45 °C for 3 seconds, and the cooling rate is 1×10 3 K / s; After quenching, stretching straightening and two-stage aging treatment are carried out within 20 minutes. The stretching rate in the stretching straightening step is 1.5%; The two-stage aging treatment includes primary aging treatment and secondary aging treatment; The primary aging treatment includes heat preservation at 120 °C for 2 hours; The secondary aging includes heat preservation at 180 °C for 10 hours, and finally an aluminum alloy profile is obtained.

[0049] Example 4 The production process of the aluminum alloy profile in this example includes steps of batching, melting and casting, homogenization treatment, extrusion molding, quenching, stretching straightening and aging treatment; Batching is carried out according to the following aluminum alloy composition: Si 0.6 - 0.65%, Fe ≤ 0.2%, Cu 0.45 - 0.55%, Mn 0.05 - 0.10%, Mg 0.9 - 0.95%, Cr 0.25 - 0.30%, Ni 0.08 - 0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04 - 0.10%, Ce 0.04 - 0.10, total of other impurities not more than 0.15%, the rest is Al.

[0050] Ingredients are prepared according to the optimized aluminum alloy composition. After melting, casting and homogenization treatment, a casting rod is obtained. The casting rod is first subjected to extrusion forming treatment. When extrusion forming, the temperature of the inlet area of the extrusion cylinder is 480 °C, the temperature of the die deformation area is 420 °C, and the extrusion speed in the die deformation area is 8 mm / s; then it undergoes quenching treatment in two stages. In the first stage, liquid nitrogen is directly sprayed for 2 seconds, and the cooling rate is 5×10 3 K / s; in the second stage, it is switched to nitrogen atomization at -55 to -45 °C for 2 seconds, and the cooling rate is 2×10 3 K / s; after quenching, stretching straightening and two-stage aging treatment are carried out within 20 minutes. The stretching rate in the stretching straightening step is 1.5%; the two-stage aging treatment includes primary aging treatment and secondary aging treatment; the primary aging treatment includes holding at 120 °C for 2 hours; the secondary aging includes holding at 180 °C for 10 hours, and finally an aluminum alloy profile is obtained.

[0051] Example 5 The production process of the aluminum alloy profile in this example includes steps of ingredient preparation, melting and casting, homogenization treatment, extrusion forming, quenching, stretching straightening and aging treatment; Ingredients are prepared according to the following aluminum alloy composition: Si 0.6 - 0.65%, Fe ≤ 0.2%, Cu 0.45 - 0.55%, Mn 0.05 - 0.10%, Mg 0.9 - 0.95%, Cr 0.25 - 0.30%, Ni 0.08 - 0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04 - 0.10%, Ce 0.04 - 0.10, total of other impurities not more than 0.15%, the rest is Al.

[0052] Ingredients are prepared according to the optimized aluminum alloy composition. After melting, casting and homogenization treatment, a casting rod is obtained. The casting rod is first subjected to extrusion forming treatment. When extrusion forming, the temperature of the inlet area of the extrusion cylinder is 480 °C, the temperature of the die deformation area is 420 °C, and the extrusion speed in the die deformation area is 8 mm / s; then it undergoes quenching treatment in two stages. In the first stage, liquid nitrogen is directly sprayed for 1 second, and the cooling rate is 1×10 4 K / s; in the second stage, it is switched to nitrogen atomization at -55 to -45 °C for 3 seconds, and the cooling rate is 1×10 3K / s; After quenching, stretching straightening and two-stage aging treatment are carried out within 20 minutes. The stretching rate in the stretching straightening step is 1.5%; The two-stage aging treatment includes primary aging treatment and secondary aging treatment; The primary aging treatment includes holding at 120°C for 2 hours; The secondary aging includes holding at 180°C for 10 hours, and finally an aluminum alloy profile is obtained.

[0053] Example 6 The production process of the aluminum alloy profile in this example includes steps of batching, melting and casting, homogenization treatment, extrusion molding, quenching, stretching straightening and aging treatment; Batching is carried out according to the following aluminum alloy composition: Si 0.6~0.65%, Fe ≤ 0.2%, Cu 0.45~0.55%, Mn 0.05~0.10%, Mg 0.9~0.95%, Cr 0.25~0.30%, Ni 0.08~0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04~0.10%, Ce 0.04~0.10, the total of other impurities is not more than 0.15%, and the rest is Al.

[0054] Batching is carried out according to the optimized aluminum alloy composition. After melting and casting and homogenization treatment, a casting rod is obtained. The casting rod is first subjected to extrusion molding treatment. When extrusion molding, the temperature in the inlet area of the extrusion cylinder is 480°C, the temperature in the die deformation area is 420°C, and the extrusion speed in the die deformation area is 8 mm / s; Then it undergoes two-stage quenching treatment. In the first stage, liquid nitrogen is directly sprayed for 1 second, and the cooling rate is 1×10 4 K / s; In the second stage, it is switched to nitrogen atomization at -55~-45°C for 5 seconds, and the cooling rate is 5×10 2 K / s; After quenching, stretching straightening and two-stage aging treatment are carried out within 20 minutes. The stretching rate in the stretching straightening step is 1.5%; The two-stage aging treatment includes primary aging treatment and secondary aging treatment; The primary aging treatment includes holding at 120°C for 2 hours; The secondary aging includes holding at 180°C for 10 hours, and finally an aluminum alloy profile is obtained.

[0055] Example 7 The production process of the aluminum alloy profile in this example includes steps of batching, melting and casting, homogenization treatment, extrusion molding, quenching, stretching straightening and aging treatment; Batching is carried out according to the following aluminum alloy composition: Si 0.6 - 0.65%, Fe ≤ 0.2%, Cu 0.45 - 0.55%, Mn 0.05 - 0.10%, Mg 0.9 - 0.95%, Cr 0.25 - 0.30%, Ni 0.08 - 0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04 - 0.10%, Ce 0.04 - 0.10%, the total of other impurities is not more than 0.15%, and the rest is Al.

[0056] Batch according to the optimized aluminum alloy composition, and obtain a cast rod after melting, casting and homogenization treatment. The cast rod is first subjected to extrusion forming treatment. When extrusion forming, the temperature of the inlet area of the extrusion cylinder is 500 °C, the temperature of the die deformation area is 440 °C, and the extrusion speed in the die deformation area is 15 mm / s; then it is subjected to quenching treatment in two stages. In the first stage, liquid nitrogen is directly sprayed for 1 second, and the cooling rate is 1×10 4 K / s; in the second stage, it is switched to nitrogen atomization at -55 to -45 °C for 2 seconds, and the cooling rate is 2×10 3 K / s; after quenching, stretching and straightening and two-stage aging treatment are carried out within 20 minutes. The stretching rate in the stretching and straightening step is 1.5%; the two-stage aging treatment includes primary aging treatment and secondary aging treatment; the primary aging treatment includes heat preservation at 120 °C for 2 hours; the secondary aging includes heat preservation at 180 °C for 10 hours, and finally an aluminum alloy profile is obtained.

[0057] Example 8 The production process of the aluminum alloy profile in this example includes steps of batching, melting, casting, homogenization treatment, extrusion forming, quenching, stretching and straightening, and aging treatment; Batch according to the following aluminum alloy composition: Si 0.6 - 0.65%, Fe ≤ 0.2%, Cu 0.45 - 0.55%, Mn 0.05 - 0.10%, Mg 0.9 - 0.95%, Cr 0.25 - 0.30%, Ni 0.08 - 0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04 - 0.10%, Ce 0.04 - 0.10%, the total of other impurities is not more than 0.15%, and the rest is Al.

[0058] Batch according to the optimized aluminum alloy composition, and obtain a cast rod after melting, casting and homogenization treatment. The cast rod is first subjected to extrusion forming treatment. When extrusion forming, the temperature of the inlet area of the extrusion cylinder is 500 °C, the temperature of the die deformation area is 440 °C, and the extrusion speed in the die deformation area is 15 mm / s; then it is subjected to quenching treatment in two stages. In the first stage, liquid nitrogen is directly sprayed for 1 second, and the cooling rate is 1×10 4 K / s; in the second stage, it is switched to nitrogen atomization at -55 to -45 °C for 2 seconds, and the cooling rate is 2×10 3K / s; After quenching, stretch straightening and two-stage aging treatment are carried out within 20 minutes. The stretching rate in the stretch straightening step is 1.5%; The two-stage aging treatment includes primary aging treatment and secondary aging treatment; The primary aging treatment includes heat preservation at 110°C for 2 hours; The secondary aging includes heat preservation at 160°C for 8 hours, and finally an aluminum alloy profile is obtained.

[0059] Example 9 The production process of the aluminum alloy profile in this example includes steps of batching, melting and casting, homogenization treatment, extrusion forming, quenching, stretch straightening and aging treatment; Batch according to the following aluminum alloy composition: Si 0.6~0.65%, Fe ≤ 0.2%, Cu 0.45~0.55%, Mn 0.05~0.10%, Mg 0.9~0.95%, Cr 0.25~0.30%, Ni 0.08~0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04~0.10%, Ce 0.04~0.10, the total of other impurities is not more than 0.15%, and the rest is Al.

[0060] Batch according to the optimized aluminum alloy composition. After melting and casting and homogenization treatment, a casting rod is obtained. The casting rod is first subjected to extrusion forming treatment. When extrusion forming, the temperature in the inlet area of the extrusion cylinder is 500°C, and the temperature in the die deformation area is 440°C. The extrusion speed in the die deformation area is 15 mm / s; Then it undergoes two-stage quenching treatment. In the first stage, liquid nitrogen is directly sprayed for 1 second, and the cooling rate is 1×10 4 K / s; In the second stage, it is switched to nitrogen atomization at -55~-45°C for 2 seconds, and the cooling rate is 2×10 3 K / s; After quenching, stretch straightening and two-stage aging treatment are carried out within 20 minutes. The stretching rate in the stretch straightening step is 1.5%; The two-stage aging treatment includes primary aging treatment and secondary aging treatment; The primary aging treatment includes heat preservation at 130°C for 3 hours; The secondary aging includes heat preservation at 190°C for 10 hours, and finally an aluminum alloy profile is obtained.

[0061] Example 10 The production process of the aluminum alloy profile in this example includes steps of batching, melting and casting, homogenization treatment, extrusion forming, quenching, stretch straightening and aging treatment; Batch according to the following aluminum alloy composition: Si 0.6 - 0.65%, Fe ≤ 0.2%, Cu 0.45 - 0.55%, Mn 0.05 - 0.10%, Mg 0.9 - 0.95%, Cr 0.25 - 0.30%, Ni 0.08 - 0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04 - 0.10%, Ce 0.04 - 0.10, the total of other impurities is not more than 0.15%, and the rest is Al.

[0062] Batch materials according to the optimized aluminum alloy composition. After melting, casting and homogenization treatment, a cast bar is obtained. The cast bar is first subjected to extrusion forming treatment. When extrusion forming, the temperature of the inlet area of the extrusion cylinder is 500 °C, the temperature of the die deformation area is 440 °C, and the extrusion speed in the die deformation area is 15 mm / s. Then, it undergoes quenching treatment in two stages. In the first stage, liquid nitrogen is directly sprayed for 1 second, and the cooling rate is 1×10 4 K / s; in the second stage, it is switched to nitrogen atomization at -55 to -45 °C for 2 seconds, and the cooling rate is 2×10 3 K / s. After quenching, stretching straightening and two-stage aging treatment are carried out within 20 minutes. The stretching rate in the stretching straightening step is 0.5%; the two-stage aging treatment includes primary aging treatment and secondary aging treatment; the primary aging treatment includes heat preservation at 120 °C for hours; the secondary aging includes heat preservation at 180 °C for 10 hours, and finally an aluminum alloy profile is obtained.

[0063] Example 11 The production process of the aluminum alloy profile in this example includes steps of batching, melting and casting, homogenization treatment, extrusion forming, quenching, stretching straightening and aging treatment; Batch materials according to the following aluminum alloy composition: Si 0.6 - 0.65%, Fe ≤ 0.2%, Cu 0.45 - 0.55%, Mn 0.05 - 0.10%, Mg 0.9 - 0.95%, Cr 0.25 - 0.30%, Ni 0.08 - 0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04 - 0.10%, Ce 0.04 - 0.10, the total of other impurities is not more than 0.15%, and the rest is Al.

[0064] Batch materials according to the optimized aluminum alloy composition. After melting, casting and homogenization treatment, a cast bar is obtained. The cast bar is first subjected to extrusion forming treatment. When extrusion forming, the temperature of the inlet area of the extrusion cylinder is 500 °C, the temperature of the die deformation area is 440 °C, and the extrusion speed in the die deformation area is 15 mm / s. Then, it undergoes quenching treatment in two stages. In the first stage, liquid nitrogen is directly sprayed for 1 second, and the cooling rate is 1×10 4 K / s; in the second stage, it is switched to nitrogen atomization at -55 to -45 °C for 2 seconds, and the cooling rate is 2×10 3K / s; After quenching, stretching straightening and two-stage aging treatment are carried out within 20 minutes. The stretching rate in the stretching straightening step is 2.5%; The two-stage aging treatment includes primary aging treatment and secondary aging treatment; The primary aging treatment includes heat preservation at 120°C for 2 hours; The secondary aging includes heat preservation at 180°C for 10 hours, and finally an aluminum alloy profile is obtained.

[0065] Comparative Example 1 The production process of the aluminum alloy profile in this embodiment includes steps of batching, melting and casting, homogenization treatment, extrusion forming, quenching, stretching straightening and aging treatment; Batching is carried out according to the following aluminum alloy composition: Si 0.6~0.65%, Fe ≤ 0.2%, Cu 0.45~0.55%, Mn 0.05~0.10%, Mg 0.9~0.95%, Cr 0.25~0.30%, Ni 0.08~0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04~0.10%, Ce 0.04~0.10, the total of other impurities is not more than 0.15%, and the rest is Al.

[0066] Batching is carried out according to the optimized aluminum alloy composition. After melting and casting and homogenization treatment, a cast rod is obtained. The cast rod is first subjected to extrusion forming treatment. When extrusion forming, the temperature in the inlet area of the extrusion cylinder is 480°C, the temperature in the die deformation area is 420°C, and the extrusion speed in the die deformation area is 8 mm / s; Then it undergoes two-stage quenching treatment. The first stage uses water mist quenching, and the second stage uses water through quenching; After quenching, stretching straightening and two-stage aging treatment are carried out within 20 minutes. The stretching rate in the stretching straightening step is 1.5%; The two-stage aging treatment includes primary aging treatment and secondary aging treatment; The primary aging treatment includes heat preservation at 120°C for 2 hours; The secondary aging includes heat preservation at 180°C for 10 hours, and finally an aluminum alloy profile is obtained.

[0067] Comparative Example 2 The production process of the aluminum alloy profile in this embodiment includes steps of batching, melting and casting, homogenization treatment, extrusion forming, quenching, stretching straightening and aging treatment; Batching is carried out according to the following aluminum alloy composition: Si 0.6~0.65%, Fe ≤ 0.2%, Cu 0.45~0.55%, Mn 0.05~0.10%, Mg 0.9~0.95%, Cr 0.25~0.30%, Ni 0.08~0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04~0.10%, Ce 0.04~0.10, the total of other impurities is not more than 0.15%, and the rest is Al.

[0068] Ingredients are prepared according to the optimized aluminum alloy composition. After melting, casting, and homogenization treatment, a cast rod is obtained. The cast rod is first subjected to extrusion forming. During extrusion forming, the temperature in the inlet area of the extrusion cylinder is 480 °C, the temperature in the die deformation area is 420 °C, and the extrusion speed in the die deformation area is 8 mm / s. Then, it is directly sprayed with liquid nitrogen for 1 second, and quenching treatment is carried out at a cooling rate of 1×10 4 K / s; After quenching, stretching straightening and double-stage aging treatment are carried out within 20 minutes. The stretching rate in the stretching straightening step is 1.5%; The double-stage aging treatment includes primary aging treatment and secondary aging treatment; The primary aging treatment includes heat preservation at 120 °C for 2 hours; The secondary aging includes heat preservation at 180 °C for 10 hours, and finally an aluminum alloy profile is obtained.

[0069] Comparative Example 3 The production process of the aluminum alloy profile in this example includes steps of ingredient preparation, melting and casting, homogenization treatment, extrusion forming, quenching, stretching straightening, and aging treatment; Ingredients are prepared according to the following aluminum alloy composition: Si 0.6~0.65%, Fe ≤0.2%, Cu 0.45~0.55%, Mn 0.05~0.10%, Mg 0.9~0.95%, Cr 0.25~0.30%, Ni 0.08~0.12%, Zn ≤0.15%, Ti ≤0.1%, La 0.04~0.10%, Ce 0.04~0.10, the total of other impurities is not more than 0.15%, and the rest is Al.

[0070] Ingredients are prepared according to the optimized aluminum alloy composition. After melting, casting, and homogenization treatment, a cast rod is obtained. The cast rod is first subjected to extrusion forming. During extrusion forming, the temperature in the inlet area of the extrusion cylinder is 480 °C, the temperature in the die deformation area is 420 °C, and the extrusion speed in the die deformation area is 8 mm / s. Then, it is atomized with nitrogen at -55~-45 °C for 3 seconds, and quenching treatment is carried out at a cooling rate of 1×10 3 K / s; After quenching, stretching straightening and double-stage aging treatment are carried out within 20 minutes. The stretching rate in the stretching straightening step is 1.5%; The double-stage aging treatment includes primary aging treatment and secondary aging treatment; The primary aging treatment includes heat preservation at 120 °C for 2 hours; The secondary aging includes heat preservation at 180 °C for 10 hours, and finally an aluminum alloy profile is obtained.

[0071] Performance test Mechanical property tests and corrosion resistance tests are carried out on Examples 1~11 and Comparative Examples 1~3, and the results are shown in Table 1.

[0072] (I) Mechanical property tests Test standards: Tensile test: GB / T228.1-2021 "Metallic materials - Tensile testing - Part 1: Method of test at room temperature" Specimen direction: Cut longitudinally along the profile (parallel to the extrusion direction) to eliminate the influence of anisotropy.

[0073] Specimen size: Gauge length 50 mm, cross-sectional size take the typical wall thickness of the profile 5 mm × 20 mm Key parameter control: Tensile rate: 0.00025 / s in the elastic stage, 0.0067 / s in the plastic stage Test temperature: 23°C ± 2°C; (2) Corrosion resistance test Neutral salt spray test (NSS): Standard: GB / T10125 - 2021 Condition: 5% NaCl solution, pH 6.5 - 7.2, continuous spraying for 720 h, for strengthening corrosion simulation of new energy vehicle coastal conditions, testing the salt spray corrosion rate.

[0074] Table 1 Performance test data

[0075] According to the above embodiments, the cooling rate in the second stage increases from 5×10 2 K / s to 2×10 3 K / s, the size of the β-phase in the core is refined, the resistance to dislocation movement increases, and the tensile strength increases linearly. Quick cooling inhibits the precipitation of coarse β-phase along the grain boundaries. As can be seen from Example 1 and Example 4, the salt spray corrosion rate decreases with the increase of the cooling rate.

[0076] In Comparative Example 1, water spray quenching results in uneven cooling and no ultra-low temperature quick cooling, so no amorphous / nanocrystalline surface layer is formed, and the strength drops suddenly by 55 MPa, and the corrosion rate increases several times. In Comparative Example 2, single-stage liquid nitrogen lacks slow cooling in the second stage, the β-phase in the core coarsens, and the corrosion resistance is only grade 8; in Comparative Example 3, there is no surface amorphous strengthening, and the strength loss is 35 MPa.

[0077] In Example 7, the extrusion cylinder / die temperature is increased to 500°C / 440°C, and the extrusion speed is 15 mm / s, which promotes dynamic recrystallization. The tensile strength reaches 350 MPa, the grain refinement reduces grain boundary defects, and the salt spray corrosion rate drops to 6.5. In Example 8, the primary aging temperature is reduced to 110°C, and the formation of GP zones is insufficient, so the strength drops back to the reference value of 325 MPa, and the corrosion rate increases; in Example 9, the secondary aging is excessively increased to 190°C, the strength only increases slightly, and the elongation drops to 10.5%, verifying the sensitivity of the two-stage aging temperature window.

[0078] Compared with the comparative examples, the tensile strength of the aluminum alloy profile prepared in the embodiments of the present invention is increased by 16% - 25%, the yield strength is increased by 20% - 30%, and the corrosion resistance is increased by 70%.

Claims

1. A production process of an aluminum alloy profile, characterized in that, Including: Steps of batching, melting and casting, homogenization treatment, extrusion forming, quenching treatment, stretch straightening and aging treatment; Among them, the quenching treatment includes two stages. In the first stage, liquid nitrogen is directly sprayed for 1 - 2 seconds; in the second stage, it is switched to nitrogen atomization at - 55~ - 45°C for 2 - 5 seconds; the cooling rate in the first stage is 5×10 3 ~2×10 4 K / s, and the cooling rate in the second stage is 5×10 2 ~2×10 3 K / s.

2. The production process of the aluminum alloy profile according to claim 1, characterized in that The temperature of the homogenization treatment is 520 - 550 °C, and the time is 5 - 10 h.

3. The production process of the aluminum alloy profile according to claim 1, characterized in that, When extrusion forming, the temperature of the inlet area of the extrusion cylinder is 480 - 500 °C, and the temperature of the die deformation area is 420 - 440 °C.

4. The production process of the aluminum alloy profile according to claim 3, characterized in that, The extrusion speed in the die deformation area is 8 - 15 mm / s.

5. The production process of the aluminum alloy profile according to claim 1, characterized in that, The batching is carried out according to the following aluminum alloy components; the aluminum alloy components include by weight percentage: Si 0.6 - 0.65%, Fe ≤ 0.2%, Cu 0.45 - 0.55%, Mn 0.05 - 0.10%, Mg 0.9 - 0.95%, Cr 0.25 - 0.30%, Ni 0.08 - 0.12%, Zn ≤ 0.15%, Ti ≤ 0.1%, La 0.04 - 0.10%, Ce 0.04 - 0.10, the total of other impurities is not more than 0.15%, and the rest is Al.

6. The production process of the aluminum alloy profile according to claim 1, characterized in that, The stretch straightening is carried out within 10 - 30 minutes after the quenching.

7. The production process of the aluminum alloy profile according to claim 1, characterized in that, In the stretch straightening step, the stretch rate is 0.5% - 2.5%.

8. The production process of the aluminum alloy profile according to claim 1, characterized in that, The aging treatment includes primary aging treatment and secondary aging treatment; The primary aging treatment includes heat preservation at 110 - 130 °C for 2 - 3 hours; The secondary aging treatment includes heat preservation at 160 - 190 °C for 8 - 10 hours.

9. An aluminum alloy profile prepared by the production process of the aluminum alloy profile according to any one of claims 1 - 8.

10. An application of the aluminum alloy profile according to claim 9 in the manufacture of new energy vehicles.

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