A method for improving the comprehensive performance of 6xxx aluminum alloy coil and aluminum alloy coil

Abstract

The present invention discloses a method for improving the comprehensive performance of 6xxx aluminum alloy coils and the aluminum alloy coils, belonging to the technical field of aluminum alloy manufacturing. The method comprises the following steps: melting and casting, homogenizing heat treatment, temperature-controlled rolling, low-temperature rolling, annealing, solution quenching, pre-deformation, and pre-aging treatment. The present invention optimizes the traditional process, shortens the production cycle, improves efficiency, and reduces energy consumption. Through the implementation of the present solution, a grain structure with an aspect ratio greater than 1.2, an average grain size of 16-22 μm, and a Cube {001} <100> Finished aluminum alloy coils with a texture ratio of 12-18%, plastic strain ratio r ≥ 0.5, anisotropy #imgabs0# < 0.1, tensile strength ≥ 250MPa, yield strength ≥ 125MPa, elongation ≥ 24%, and bake hardening peak increment of 90-150MPa.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy manufacturing, and in particular to a method for improving the comprehensive performance of a 6xxx aluminum alloy coil and the aluminum alloy coil. Background Art

[0002] 6xxx aluminum alloy has become the preferred material for automotive exterior panels due to its comprehensive performance. The new alloy performs outstandingly in pedestrian protection and recycling. Other covering parts such as doors, trunk lids, fenders, etc. are also gradually being aluminumized. In addition, aluminum alloy has high recycling value. The increase in aluminum consumption in the whole vehicle is conducive to the reuse of scrap metal from dismantled vehicles.

[0003] The 6xxx series aluminum alloy used for car bodies is in the T4 state before baking, with an excellent yield strength ratio, which is conducive to stamping. The stamped parts are age-hardened during the electrophoretic paint process. High-alloyed 6xxx aluminum alloys such as 6111 alloy sheets have higher strength than 6014 / 6016 / 6022 after baking, but their stamping capabilities are slightly weaker. The conventional production process of 6xxx~T4 aluminum alloy products is: melting and casting → homogenization heat treatment → cutting head and tail → milling → hot rolling → cold rolling → intermediate annealing → cold rolling → quenching → pre-aging. The process flow is complex, the production cycle is long, the efficiency is low, and the energy consumption is high. Application number CN202210878837.0 is a preparation method for 6xxx aluminum alloy coils with separate homogenization and heating. It requires two cold rolling processes, has a long production cycle, a high temperature in the annealing step, and high energy consumption. The final rolling temperature during hot rolling is relatively low, at 240~280℃, which is not conducive to dynamic recrystallization and texture ratio adjustment.

[0004] Based on this, we hope to explore a method to improve the comprehensive performance of 6xxx aluminum alloy coils, optimize the production process and production technology, shorten the production cycle, improve efficiency, reduce energy consumption, reduce product anisotropy, and improve stamping forming ability and aging response ability. Summary of the Invention

[0005] In view of the above shortcomings, the present invention provides a method for improving the comprehensive performance of 6xxx aluminum alloy coils, which is beneficial to improving the tensile strength, yield strength and elongation performance of the aluminum alloy coils, shortening the production cycle, improving efficiency and reducing energy consumption. Through the implementation of this solution, a grain structure with an aspect ratio of >1.2, an average grain size of 16~22μm, and a Cube{001} <100> Aluminum alloy coil products with a texture ratio of 12~18%, plastic strain ratio r≥0.5, anisotropic <0.1, the bake hardening value increment reaches 90~150MPa. The specific technical solution is as follows:

[0006] A method for improving the comprehensive performance of 6xxx aluminum alloy coils, comprising the following steps:

[0007] S1. Melting and casting: Melting and casting the aluminum alloy raw material to obtain an ingot;

[0008] S2, homogenization heat treatment: the ingot obtained in step S1 is cut and milled, and then subjected to homogenization heat treatment to obtain an ingot after homogenization heat treatment;

[0009] S3, temperature-controlled rolling: The ingot obtained in step S2 after homogenization heat treatment is subjected to temperature-controlled rolling, wherein the metal temperature is controlled at 350-450°C during the rolling process, and the total rolling processing rate is greater than 60%, thereby obtaining a temperature-controlled rolled coil;

[0010] S4, low temperature rolling: performing low temperature rolling on the temperature-controlled rolled coil obtained in step S3 to obtain a low temperature rolled coil;

[0011] S5, annealing: annealing the low-temperature rolled coil obtained in step S4 at a temperature of 320-360° C. for a holding time of 0.2-1 h to obtain an annealed coil;

[0012] S6, solution quenching: subjecting the annealed coil obtained in step S5 to solution quenching to obtain a solution quenched coil;

[0013] S7, pre-deformation: pre-deform the solution quenched coil obtained in step S6, with a pre-stretching rate of 0.2-1.0%, to obtain a pre-deformed coil;

[0014] S8, pre-aging treatment: The pre-deformed coil obtained in step S7 is subjected to pre-aging treatment to obtain a finished aluminum alloy coil.

[0015] The mass percentages of the chemical components of the aluminum alloy are: Si=0.9~1.8%, Fe=0.2~0.8%, Cu=0.2~0.5%, Mn=0.1~0.5%, Mg=0.6~1.2%, Cr≤0.25%, Zn≤0.3%, Ti≤0.1%, and the balance is Al and unavoidable impurity elements.

[0016] Furthermore, the holding temperature of the homogenization heat treatment is 530-560° C., and the holding time is 6-12 hours.

[0017] Furthermore, the low-temperature rolling temperature is 10-60° C., and the total rolling processing rate is greater than 60%.

[0018] Furthermore, the solution quenching holding temperature is 540-570° C., and the holding time is 0.2-1 h.

[0019] Furthermore, the pre-aging treatment temperature is 70-150° C., and the holding time is 3-25 hours.

[0020] Furthermore, in the solution quenching step, the cooling rate is greater than 45°C / s.

[0021] The present invention also provides a 6xxx aluminum alloy coil product prepared by the above preparation method.

[0022] Furthermore, the 6xxx aluminum alloy coil of the present invention has a grain structure with an aspect ratio greater than 1.2, an average grain size of 16 to 22 μm, and a Cube {001} <100> Texture ratio is 12~18%.

[0023] Furthermore, the performance of the 6xxx aluminum alloy coil product of the present invention meets the following requirements:

[0024] Tensile strength ≥250MPa, yield strength ≥125MPa, elongation ≥24%, bake hardening peak increment reaches 90~150MPa;

[0025] Plastic strain ratio r≥0.5, anisotropy index Δr<0.1.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention provides a method for improving the comprehensive performance of 6xxx aluminum alloy coils, comprising the following steps: melting and casting, homogenizing heat treatment, temperature-controlled rolling, low-temperature rolling, annealing, solution quenching, pre-deformation, and pre-aging treatment. The present invention optimizes the production process and production technology, shortens the production cycle, improves efficiency, and reduces energy consumption.

[0028] 2. In the method of the present invention, the temperature-controlled hot rolling process is conducive to dynamic recrystallization and texture ratio adjustment. Combined with low-temperature rolling, it can increase energy storage and lattice distortion. Static recrystallization occurs rapidly during a short annealing process of 320-360°C / 0.2-1h, followed by immediate quenching, resulting in a quenched structure with elliptical grains with an aspect ratio greater than 1.2, and a reduced average grain size, thereby making the grains of the aluminum alloy coil fine, thereby improving the mechanical properties of the aluminum alloy; pre-aging treatment after 0.2-1.0% pre-stretching deformation can obtain a more uniformly dispersed GP zone, which is beneficial to improving the tensile strength, yield strength and elongation properties.

[0029] 3. The method of the present invention can obtain a grain structure with a major-minor axis ratio of >1.2, an average grain size of 16~22μm, and a Cube{001} <100> Aluminum alloy coil products with a texture ratio of 12~18%, plastic strain ratio r≥0.5, anisotropic <0.1, tensile strength ≥250MPa, yield strength ≥125MPa, elongation ≥24%, and bake hardening peak increment reaches 90~150MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are some embodiments of the present invention, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0031] Figure 1 It is a process flow diagram of the present invention;

[0032] Figure 2 This is an EBSD test image of the grain structure of the finished aluminum alloy coil of Example 1 of the present invention;

[0033] Figure 3 This is the texture ratio EBSD test diagram of the finished aluminum alloy coil of Example 1 of the present invention. DETAILED DESCRIPTION

[0034] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited by the specific embodiments. Unless otherwise defined, all technical terms used hereinafter have the same meaning as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or can be prepared by existing methods.

[0035] Reference Figure 1 The process flow of the embodiment of the present invention includes the following steps:

[0036] Melting and casting: Melting and casting the aluminum alloy raw materials to obtain ingots;

[0037] Homogenization heat treatment: The obtained ingot is cut and milled, and then subjected to homogenization heat treatment at a holding temperature of 530-560°C for 6-12 hours to obtain an ingot after homogenization heat treatment;

[0038] Temperature-controlled rolling: The ingot obtained after homogenization heat treatment is subjected to temperature-controlled rolling. The metal temperature is controlled at 350-450°C during the rolling process, and the total rolling processing rate is greater than 60%, thereby obtaining a temperature-controlled rolled coil.

[0039] Low temperature rolling: The obtained temperature-controlled rolled coil is subjected to low temperature rolling, the metal temperature is controlled to be 10-60°C during the rolling process, and the total rolling processing rate is greater than 60%, thereby obtaining a low temperature rolled coil;

[0040] Annealing: annealing the obtained low-temperature rolled coil at a holding temperature of 320-360°C for 0.2-1h to obtain an annealed coil;

[0041] Solution quenching: The annealed coil is solution quenched at a holding temperature of 540-570°C for 0.2-1h and a cooling rate of >45°C / s to obtain a solution quenched coil.

[0042] Pre-deformation: pre-deform the obtained solution quenched coil with a pre-stretching rate of 0.2-1.0% to obtain a pre-deformed coil;

[0043] Pre-aging treatment: The obtained pre-deformed coil is subjected to pre-aging treatment, with a holding temperature of 70-150° C. for 3-25 hours, and then cooled to obtain a finished aluminum alloy coil.

[0044] Example 1

[0045] The mass percentages of the chemical composition of the aluminum alloy in this embodiment are: Si=1.3%, Fe=0.6%, Cu=0.3%, Mn=0.3%, Mg=0.8%, Cr=0.20%, Zn=0.2%, Ti=0.03%, and the remainder is Al and unavoidable impurity elements.

[0046] Reference Figure 1 A method for improving the comprehensive performance of a 6xxx aluminum alloy coil according to this embodiment includes the following steps:

[0047] S1. Melting and casting: Melting and casting the aluminum alloy raw material to obtain an ingot;

[0048] S2, homogenization heat treatment: the ingot obtained in step S1 is cut and milled, and then subjected to homogenization heat treatment at a holding temperature of 545° C. for 9 hours to obtain an ingot after homogenization heat treatment;

[0049] S3, temperature-controlled rolling: The ingot obtained in step S2 after homogenization heat treatment is subjected to temperature-controlled rolling, with the starting rolling temperature being 400° C., the metal temperature being controlled at 350-450° C. during the rolling process, and the total rolling processing rate being 70%, to obtain a temperature-controlled rolled coil;

[0050] S4, low temperature rolling: the temperature-controlled rolled coil obtained in step S3 is subjected to low temperature rolling, the metal temperature is controlled to be 30-40°C during the rolling process, and the total rolling processing rate is 70%, to obtain a low temperature rolled coil;

[0051] S5, annealing: annealing the low-temperature rolled coil obtained in step S4 at an annealing temperature of 340° C. for a holding time of 0.6 h to obtain an annealed coil;

[0052] S6, solution quenching: The annealed coil obtained in step S5 is solution quenched at a holding temperature of 555°C, a holding time of 0.6 h, and a cooling rate of 55°C / s to obtain a solution quenched coil;

[0053] S7, pre-deformation: pre-deform the solution quenched coil obtained in step S6, with a pre-stretching rate of 0.6%, to obtain a pre-deformed coil;

[0054] S8, pre-aging treatment: The pre-deformed coil obtained in step S7 is subjected to pre-aging treatment at a temperature of 110° C. for 15 hours, and the finished aluminum alloy coil is obtained after cooling.

[0055] Figure 2 This is an EBSD test image of the grain structure of the finished aluminum alloy coil in Example 1. The grain structure of the finished aluminum alloy coil shows recrystallization characteristics, and the grains are elliptical. Based on this image, ImageJ software can be used to measure the average major and minor axis sizes of the grains. The calculated major-minor axis ratio is greater than 1.2, and the calculated average grain size reaches 21 μm. Fine grains can further improve the mechanical properties of the finished aluminum alloy coil. Figure 3 This is the EBSD test diagram of the texture ratio of the finished aluminum alloy coil in Example 1, which shows the grain orientation distribution and texture ratio. Figure 3 Cube {001} is displayed on the right <100> The texture ratio is 15%, indicating that Example 1 successfully adjusts the texture ratio required for the finished aluminum alloy coil.

[0056] Example 2

[0057] The mass percentages of the chemical composition of the aluminum alloy in this embodiment are: Si=1.2%, Fe=0.3%, Cu=0.3%, Mn=0.2%, Mg=0.8%, Cr=0.13%, Zn=0.1%, Ti=0.06%, and the remainder is Al and unavoidable impurity elements.

[0058] Reference Figure 1 A method for improving the comprehensive performance of a 6xxx aluminum alloy coil according to this embodiment includes the following steps:

[0059] S1. Melting and casting: Melting and casting the aluminum alloy raw material to obtain an ingot;

[0060] S2, homogenization heat treatment: the ingot obtained in step S1 is cut and milled, and then subjected to homogenization heat treatment at a holding temperature of 530° C. for 12 h to obtain an ingot after homogenization heat treatment;

[0061] S3, temperature-controlled rolling: The ingot obtained in step S2 after homogenization heat treatment is subjected to temperature-controlled rolling, with the starting rolling temperature at 370°C, the metal temperature being controlled at 350-450°C during the rolling process, and the total rolling processing rate being 65%, to obtain a temperature-controlled rolled coil;

[0062] S4, low temperature rolling: the temperature-controlled rolled coil obtained in step S3 is subjected to low temperature rolling, the metal temperature is controlled to be 15-25°C during the rolling process, and the total rolling processing rate is 65%, to obtain a low temperature rolled coil;

[0063] S5, annealing: annealing the low-temperature rolled coil obtained in step S4 at an annealing temperature of 320° C. for 1 hour to obtain an annealed coil;

[0064] S6, solution quenching: The annealed coil obtained in step S5 is solution quenched at a holding temperature of 540°C for 1 hour and a cooling rate of 50°C / s to obtain a solution quenched coil;

[0065] S7, pre-deformation: pre-deform the solution quenched coil obtained in step S6, with a pre-stretching rate of 0.2% to obtain a pre-deformed coil;

[0066] S8, pre-aging treatment: the pre-deformed coil obtained in step S7 is subjected to pre-aging treatment at a temperature of 70° C. for 25 h, and the finished aluminum alloy coil is obtained after cooling.

[0067] Example 3

[0068] The mass percentages of the chemical composition of the aluminum alloy of this embodiment are: Si=1.6%, Fe=0.7%, Cu=0.2%, Mn=0.4%, Mg=1.1%, Cr=0.23%, Zn=0.3%, Ti=0.1%, and the balance is Al and unavoidable impurity elements.

[0069] Reference Figure 1 A method for improving the comprehensive performance of a 6xxx aluminum alloy coil according to this embodiment includes the following steps:

[0070] S1. Melting and casting: Melting and casting the aluminum alloy raw material to obtain an ingot;

[0071] S2, homogenization heat treatment: the ingot obtained in step S1 is cut and milled, and then subjected to homogenization heat treatment at a holding temperature of 560° C. for 6 hours to obtain an ingot after homogenization heat treatment;

[0072] S3, temperature-controlled rolling: The ingot obtained in step S2 after homogenization heat treatment is subjected to temperature-controlled rolling, with the starting rolling temperature being 450° C., the metal temperature being controlled at 350-450° C. during the rolling process, and the total rolling processing rate being 72%, to obtain a temperature-controlled rolled coil;

[0073] S4, low temperature rolling: the temperature-controlled rolled coil obtained in step S3 is subjected to low temperature rolling, the metal temperature is controlled to be 50-60°C during the rolling process, and the total rolling processing rate is 72%, thereby obtaining a low temperature rolled coil;

[0074] S5, annealing: annealing the low-temperature rolled coil obtained in step S4 at an annealing temperature of 360° C. for a holding time of 0.2 h to obtain an annealed coil;

[0075] S6, solution quenching: The annealed coil obtained in step S5 is solution quenched at a holding temperature of 570°C, a holding time of 0.2 h, and a cooling rate of 60°C / s to obtain a solution quenched coil;

[0076] S7, pre-deformation: pre-deform the solution quenched coil obtained in step S6, with a pre-stretching rate of 0.9% to obtain a pre-deformed coil;

[0077] S8, pre-aging treatment: the pre-deformed coil obtained in step S7 is subjected to pre-aging treatment at a temperature of 150° C. for 3 hours, and the finished aluminum alloy coil is obtained after cooling.

[0078] Comparative Example 1

[0079] The temperature-controlled rolling process of this comparative example is as follows: the hot rolling start temperature is 400°C, the hot rolling finish temperature is 250°C, and the total rolling processing rate is 70%. The remaining processes are the same as those in Example 1.

[0080] Comparative Example 2

[0081] In this comparative example, no annealing process is performed after low-temperature rolling, and the solid solution quenching process is directly performed.

[0082] The mass percentages of the chemical composition of the aluminum alloy in this comparative example are: Si=1.3%, Fe=0.6%, Cu=0.3%, Mn=0.3%, Mg=0.8%, Cr=0.20%, Zn=0.2%, Ti=0.03%, and the balance are Al and unavoidable impurity elements.

[0083] A method for improving the comprehensive performance of a 6xxx aluminum alloy coil in this comparative example comprises the following steps:

[0084] S1. Melting and casting: Melting and casting the aluminum alloy raw material to obtain an ingot;

[0085] S2, homogenization heat treatment: the ingot obtained in step S1 is cut and milled, and then subjected to homogenization heat treatment at a holding temperature of 545° C. for 9 hours to obtain an ingot after homogenization heat treatment;

[0086] S3, temperature-controlled rolling: The ingot obtained in step S2 after homogenization heat treatment is subjected to temperature-controlled rolling, with the starting rolling temperature being 400° C., the metal temperature being controlled at 350-450° C. during the rolling process, and the total rolling processing rate being 70%, to obtain a temperature-controlled rolled coil;

[0087] S4, low temperature rolling: the temperature-controlled rolled coil obtained in step S3 is subjected to low temperature rolling, the metal temperature is controlled to be 30-40°C during the rolling process, and the total rolling processing rate is 70% to obtain the low temperature rolled coil;

[0088] S5, solution quenching: The annealed coil obtained in step S4 is solution quenched at a holding temperature of 555°C for 0.6 h and a cooling rate of 55°C / s to obtain a solution quenched coil;

[0089] S6, pre-deformation: pre-deform the solution quenched coil obtained in step S5, with a pre-stretching rate of 0.6%, to obtain a pre-deformed coil;

[0090] S7, pre-aging treatment: the pre-deformed coil obtained in step S6 is subjected to pre-aging treatment at a temperature of 110° C. for 15 hours, and the finished aluminum alloy coil is obtained after cooling.

[0091] Comparative Example 3

[0092] The mass percentages of the chemical composition of the aluminum alloy in this comparative example are: Si=1.2%, Fe=0.6%, Cu=0.3%, Mn=0.4%, Mg=0.9%, Cr=0.21%, Zn=0.2%, Ti=0.08%, and the balance are Al and unavoidable impurity elements.

[0093] A method for improving the comprehensive performance of a 6xxx aluminum alloy coil in this comparative example comprises the following steps:

[0094] S1. Melting and casting: Melting and casting the aluminum alloy raw material to obtain an ingot;

[0095] S2, homogenization heat treatment: the ingot obtained in step S1 is cut off at the head and tail, and the surface is milled, and then subjected to homogenization heat treatment at a holding temperature of 545° C. for 9 hours. After the treatment, the top and bottom are sawed and the surface is milled to obtain the ingot after homogenization heat treatment;

[0096] S3, temperature-controlled rolling: The ingot obtained in step S2 after homogenization heat treatment is subjected to temperature-controlled rolling, with the starting rolling temperature being 400°C, the total rolling processing rate being 70%, and the metal temperature being controlled at 350-450°C during the rolling process to obtain a temperature-controlled rolled coil;

[0097] S4, annealing: annealing the temperature-controlled rolled coil obtained in step S3 at an annealing temperature of 340° C. for a holding time of 0.6 h to obtain an annealed coil;

[0098] S5, low temperature rolling: the annealed coil obtained in step S4 is subjected to low temperature rolling at a rolling temperature of 30-40°C and a total rolling processing rate of 70%, to obtain a low temperature rolled coil;

[0099] S6, solution quenching: The low-temperature rolled coil obtained in step S5 is solution quenched at a holding temperature of 555°C, a holding time of 0.6 h, and a cooling rate of 55°C / s to obtain a solution quenched coil;

[0100] S7, pre-deformation: pre-deform the solution quenched coil obtained in step S6, with a pre-stretching rate of 0.6%, to obtain a pre-deformed coil;

[0101] S8, pre-aging treatment: The pre-deformed coil obtained in step S7 is subjected to pre-aging treatment at a temperature of 110° C. for 15 hours, and the finished aluminum alloy coil is obtained after cooling.

[0102] Comparative Example 4

[0103] The mass percentages of the chemical composition of the aluminum alloy in this comparative example are: Si=1.0%, Fe=0.2%, Cu=0.1%, Mn=0.1%, Mg=0.5%, Cr=0.1%, Zn=0.05%, Ti=0.08%, and the balance are Al and unavoidable impurity elements.

[0104] A method for improving the comprehensive performance of a 6xxx aluminum alloy coil in this comparative example comprises the following steps:

[0105] S1. Melting and casting: Melting and casting the aluminum alloy raw material to obtain an ingot;

[0106] S2, homogenization heat treatment: the ingot obtained in step S1 is cut and milled, and then subjected to homogenization heat treatment at a holding temperature of 565° C. for 15 hours to obtain an ingot after homogenization heat treatment;

[0107] S3, hot rolling: hot rolling the ingot obtained after homogenization heat treatment in step S2, with a starting rolling temperature of 500°C, a total rolling processing rate of 70%, and a finishing rolling temperature of 300°C to obtain a hot-rolled coil;

[0108] S4, cold rolling: cold rolling the hot rolled coil obtained in step S3, with the metal temperature during the rolling process being 30-40°C and the total rolling processing rate being 70%, to obtain a cold rolled coil;

[0109] S5, solution quenching: The cold-rolled coil obtained in step S4 is solution quenched at a holding temperature of 555° C. for 0.6 h to obtain a solution quenched coil;

[0110] S6. Pre-aging treatment: The solution quenched coil obtained in step S5 is subjected to pre-aging treatment at a temperature of 110° C. for 15 h, and the finished aluminum alloy coil is obtained after cooling.

[0111] The finished aluminum alloy coils of the examples and comparative examples were subjected to microstructure tests and performance tests.

[0112] The grain size of the finished aluminum alloy coil was detected using the intercept method using ImageJ software; Cube{001} <100> The texture ratio was detected using electron backscatter diffraction (EBSD) technology. The finished aluminum alloy coil was subjected to room temperature tensile performance testing after 7 days of natural aging at room temperature. The room temperature tensile test was carried out according to the requirements of GB / T 228.1-2021. The plastic strain ratio r value and plane anisotropy index The test was carried out according to GB / T 5027-2007.

[0113] The results are shown in Table 1 below.

[0114] Table 1 Microstructure and performance test results of the finished aluminum alloy coils of the embodiments and comparative examples

[0115]

[0116] In summary, the present invention provides a method for improving the comprehensive performance of 6xxx aluminum alloy coils, including the following steps: melting, homogenization heat treatment, temperature-controlled rolling, low-temperature rolling, annealing, solution quenching, pre-deformation, and pre-aging treatment. The temperature-controlled hot rolling process of the present invention is conducive to dynamic recrystallization and texture ratio adjustment. Combined with low-temperature rolling, it can increase energy storage and lattice distortion. Static recrystallization occurs rapidly during the short annealing process of 320~360℃ / 0.2~1h, and then quenching is immediately performed to obtain The quenched structure of elliptical grains with a major-minor axis ratio of >1.2 and the average grain size are reduced, thereby making the grains of the finished aluminum alloy coil fine, thereby improving the mechanical properties of the finished aluminum alloy coil. After 0.2~1.0% pre-stretching deformation and pre-aging treatment, a more uniformly dispersed GP zone can be obtained, which is beneficial to improving the tensile strength, yield strength and elongation properties. Through the implementation of this scheme, a grain structure with a major-minor axis ratio of >1.2, an average grain size of 16~22μm, and Cube{001} <100> Aluminum alloy coil products with a texture ratio of 12~18%, plastic strain ratio r≥0.5, anisotropic <0.1, tensile strength ≥250MPa, yield strength ≥125MPa, elongation ≥24%, and bake hardening peak increment reaches 90~150MPa.

[0117] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for improving the comprehensive performance of 6xxx aluminum alloy coil, characterized in that: The steps include: S1. Melting and casting: Melting and casting the aluminum alloy raw material to obtain an ingot; S2, homogenization heat treatment: the ingot obtained in step S1 is cut and milled, and then subjected to homogenization heat treatment, with the holding temperature of the homogenization heat treatment being 530-560° C. and the holding time being 6-12 hours to obtain the ingot after homogenization heat treatment; S3, temperature-controlled rolling: The ingot obtained in step S2 after homogenization heat treatment is subjected to temperature-controlled rolling, wherein the metal temperature is controlled to be 350-450°C during the rolling process, and the total rolling processing rate is greater than 60%, thereby obtaining a temperature-controlled rolled coil; S4, low temperature rolling: the temperature-controlled rolled coil obtained in step S3 is subjected to low temperature rolling, the low temperature rolling temperature is 10-60°C, the total rolling processing rate is greater than 60%, and a low temperature rolled coil is obtained; S5, annealing: annealing the low-temperature rolled coil obtained in step S4 at a temperature of 320-360° C. for a holding time of 0.2-1 h to obtain an annealed coil; S6, solution quenching: The annealed coil obtained in step S5 is solution quenched, with the solution quenching holding temperature being 540-570°C, the holding time being 0.2-1h, and the cooling rate being >45°C / s to obtain a solution quenched coil; S7, pre-deformation: pre-deform the solution quenched coil obtained in step S6, with a pre-stretching rate of 0.2-1.0%, to obtain a pre-deformed coil; S8, pre-aging treatment: The pre-deformed coil obtained in step S7 is subjected to pre-aging treatment at a temperature of 70-150° C. for a holding time of 3-25 hours to obtain a finished aluminum alloy coil; The mass percentages of the chemical components of the aluminum alloy are: Si=0.9~1.8%, Fe=0.2~0.8%, Cu=0.2~0.5%, Mn=0.1~0.5%, Mg=0.6~1.2%, Cr≤0.25%, Zn≤0.3%, Ti≤0.1%, and the balance is Al and unavoidable impurity elements.

2. A 6xxx aluminum alloy coil prepared by the method of claim 1.

3. The 6xxx aluminum alloy coil according to claim 2, wherein: The aspect ratio of its grain structure is >1.2, the average grain size is 16~22μm, and the Cube{001} <100> Texture ratio is 12~18%.

4. The 6xxx aluminum alloy coil according to claim 2, wherein: Its performance meets: Tensile strength ≥250MPa, yield strength ≥125MPa, elongation ≥24%, bake hardening peak increment reaches 90~150MPa; Plastic strain ratio r≥0.5, anisotropy index Δr<0.1.

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