High-performance edge-covering formed 6-series aluminum alloy plate and preparation method thereof

Abstract

The invention relates to the field of improvement of forming performance of aluminum alloy plates, in particular to a high-performance edge-covering formed 6-series aluminum alloy plate and a preparation method of the high-performance edge-covering formed 6-series aluminum alloy plate. The content of Fe is smaller than or equal to 0.15%; the content of Cu is 0.13 to 0.17 percent; the content of Mn is 0.08 to 0.12 percent; the content of Mg is 0.50 to 0.60 percent; the content of Cr is 0.04 to 0.06 percent; the content of Ni is less than or equal to 0.02%; the content of Zn is less than or equal to 0.10%; the content of Ti is 0.02 to 0.04 percent; the V content is less than or equal to 0.02%; the content of Zr is 0.04 to 0.06 percent; the content of Sn is 0.005 to 0.015 percent; the content of Er is 0.17 to 0.23 percent; the single content of other impurity elements is less than or equal to 0.03%; the total content of other impurity elements is less than or equal to 0.1%; the balance is Al; the ratio of the content of Mg to the content of Si is 1: (1-1.3), the plate has excellent flanging performance and mechanical performance, the edge forming stability is high, and the rejection rate is low.

Description

Technical Field

[0001] The present invention relates to the field of improving the forming performance of aluminum alloy plates, and in particular to a high-performance edge-formed 6-series aluminum alloy plate and a preparation method thereof. Background Art

[0002] With the development of the automotive industry, people have put forward higher requirements for the safety and lightweight of automobiles. Lightweighting of automobiles means reducing the overall weight of the automobile as much as possible while ensuring the strength and safety performance of the automobile, thereby improving the power of the automobile, reducing fuel consumption, and reducing exhaust pollution. Aluminum alloy has become the most ideal material for lightweighting automobiles due to its high strength and stiffness, good impact resistance, excellent processing formability and extremely high recycling rate.

[0003] 6XXX series aluminum alloys are commonly used in automobile body panels. In addition to having good surface quality, excellent mechanical properties and high bake hardening properties, they also have high requirements for flanging performance. During the automobile panel forming process, excellent flanging performance can ensure that no microcracks are generated on the surface of the material when the panel outer panel is wrapped around the panel inner panel by flanging (edge wrapping). 6 series aluminum alloy sheets produced by existing technologies are prone to edge cracks, low forming limits and poor process stability under complex stamping conditions. Adjusting the aluminum alloy composition or introducing alloy components will change the aluminum alloy microstructure, making it difficult to process or reducing the mechanical properties.

[0004] Therefore, there is an urgent need to provide a 6 series aluminum alloy plate having both excellent flanging performance and mechanical properties and a preparation method thereof. Summary of the Invention

[0005] The present invention aims to solve the technical problem of how to provide a 6 series aluminum alloy plate having both excellent flanging performance and mechanical properties and a preparation method thereof.

[0006] In order to achieve the above-mentioned object, the first aspect of the present invention provides a high-performance hemmed 6 series aluminum alloy plate, wherein the components and their weight percentages in the plate are as follows: Si content is 0.45-0.55%; Fe content ≤ 0.15%; Cu content is 0.13-0.17%; Mn content is 0.08-0.12%; Mg content is 0.50-0.60%; Cr content is 0.04-0.06%; Ni content ≤ 0.02%; Zn content ≤ 0.10%; Ti content is 0.02-0.04%; V content ≤ 0.02%; Zr content is 0.04-0.06%; Sn content is 0.005-0.015%; Er content is 0.17-0.23%; The content of other impurity elements is ≤0.03%; The total content of other impurity elements is ≤0.1%; The remainder is Al; Among them, the ratio of Mg to Si content is 1:1-1.3.

[0007] A second aspect of the present invention provides a method for preparing the high-performance hemmed 6-series aluminum alloy sheet, wherein the method comprises: Casting, homogenization treatment, hot rolling, cold rolling, continuous annealing; The homogenization treatment conditions include: 565-575°C × 4-8h.

[0008] The beneficial effects of the present invention are: (1) The present invention introduces trace elements such as Er and Sn into the 6014 aluminum alloy system to synergistically optimize microstructure refinement and thermal stability, effectively improving edge ductility. Compared with the traditional composition system based on Mg, Si, and Cu, the composition design of the present invention helps to control the formation of brittle phases (such as AlFeSi) and reduce edge crack sensitivity.

[0009] (2) The present invention clarifies the key parameters of each link of soaking, hot rolling, cold rolling and annealing, such as final rolling temperature, coiling temperature, cold rolling speed, and intermediate annealing system, to achieve the coordinated optimization of composition and process; in particular, by controlling the rolling temperature and speed, the formation of a high proportion of Cube texture is promoted, and the texture uniformity and crack resistance of the hemming part are significantly improved; the design of the intermediate annealing system can effectively interrupt the unfavorable texture inheritance and improve the recrystallization quality. It is suitable for complex flanging forming conditions such as automotive exterior panels, and can improve the edge forming stability of the material during batch stamping and reduce the scrap rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a photograph of the aluminum alloy plate of Example 1 after bending without cracking; Figure 2 This is a photograph of the aluminum alloy plate of Comparative Example 17 after bending without cracking; Figure 3 This is a photograph of the aluminum alloy plate of Comparative Example 18 after bending without cracking. DETAILED DESCRIPTION

[0011] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0012] In the existing technology, it is difficult to prepare 6 series aluminum alloy plates with both mechanical properties and flanging properties due to the existing alloy composition and preparation process, making it difficult for the aluminum alloy plates to meet the use requirements.

[0013] In the present invention, the inventors discovered that simply controlling the alloy composition or introducing alloy elements will cause changes in the microstructure of the aluminum alloy plate, and the mechanical properties and flanging performance of the aluminum alloy plate cannot be improved simultaneously during the subsequent processing. The traditional composition design fails to effectively suppress grain coarsening and uneven texture, resulting in unsatisfactory recrystallization texture distribution and insufficient Cube texture ratio, which affects edge plasticity. It is necessary to control the alloy composition and coordinate the regulation process to produce 6 series aluminum alloy plates with both mechanical properties and flanging performance.

[0014] To achieve this goal, the inventors attempted to optimize the component composition and processing technology of 6 series aluminum alloy plates. The inventors found that the hot rolling and cold rolling deformation processes lacked a systematic matching design, the final rolling temperature, coiling temperature and rolling speed were roughly controlled, and the texture control effect was poor; through specific component composition and homogenization treatment technology, the above purpose can be achieved. Furthermore, specific hot rolling, cold rolling and solution heat treatment processes make the performance of aluminum alloy plates even better.

[0015] A first aspect of the present invention provides a high-performance hemmed 6-series aluminum alloy plate, wherein the components and their weight percentages in the plate are: Si content is 0.45-0.55%; Fe content ≤ 0.15%; Cu content is 0.13-0.17%; Mn content is 0.08-0.12%; Mg content is 0.50-0.60%; Cr content is 0.04-0.06%; Ni content ≤ 0.02%; Zn content ≤ 0.10%; Ti content is 0.02-0.04%; V content ≤ 0.02%; Zr content is 0.04-0.06%; Sn content is 0.005-0.015%; Er content is 0.17-0.23%; The content of other impurity elements is ≤0.03%; The total content of other impurity elements is ≤0.1%; The remainder is Al; Among them, the ratio of Mg to Si content is 1:1-1.3.

[0016] In the present invention, Er in the range of 0.1-0.3% can significantly refine α-Al grains. When it exceeds 0.25%, coarse Al3Er phase or segregation is easily formed, affecting the uniformity of continuous rolling and annealing. The Er content range of the present invention takes into account both the refinement effect and dissolution stability. Trace amounts of Sn can effectively inhibit natural aging and dislocation drag effects. However, when Sn is greater than 0.02%, Sn-rich areas are easily formed at grain boundaries, resulting in increased aging sensitivity. The Sn content range of the present invention, combined with the pre-aging system, can control the microstructure.

[0017] Fe is the main component of AlFeSi phase. Reducing the total amount of Fe is the basic control method to reduce the source of brittle phase. Cr can compete with Fe to form dispersed Al 13 Cr2 particles inhibit the nucleation of AlFeSi eutectic and reduce coarse phases. Ti, Fe and Si form fine Al-Ti-Fe particles or Al3Ti as grain refinement cores, inhibiting elongated eutectics. In traditional 6014 aluminum alloys, if the Fe content is high or the cooling is improperly controlled, lamellar, spiculate or network-shaped AlFeSi brittle phases (such as β-AlFeSi, Al7Cu2Fe, π phase, etc.) are easily formed. These brittle phases have the ability to destroy the continuous recrystallization structure and induce crack initiation; reduce edge ductility and anti-edge wrapping ability; increase local strain concentration areas and reduce the negative impact of the forming limit angle. Both Cr and Ti can induce the formation of blocky or spherical dispersed particles, thereby interrupting the growth direction and connectivity of the original AlFeSi, transforming the forming into a more passive phase, which is beneficial to improving edge forming toughness. The present invention limits the Fe content to ≤0.15% to avoid the formation of a large amount of β phase. Ti and Cr form fine particles with Fe within the range defined by the present invention and control their nucleation.

[0018] The specific Mg to Si content ratio of the present invention ensures the stable formation of the strengthening phase, improves the edge wrapping limit angle, and maintains the aging performance and corrosion resistance at the same time. When the Mg to Si content ratio is greater than 1.3, there is too much residual Mg, forming a non-strengthening Mg-rich phase, such as Mg5Al2Si4, which over-ages quickly after the aging peak and reduces edge toughness; the corrosion resistance decreases and the risk of grain boundary anodization increases. When the Mg to Si content ratio is less than 1, Si is enriched, and eutectic Si or needle-shaped Si sheets may be generated, which increases the content of grain boundary brittle phase, poor ductility after cold rolling, and is prone to edge cracking.

[0019] In 6xxx series aluminum alloys (particularly 6014), Mg and Si are the primary elements that form the strengthening phase Mg2Si. Controlling their molar ratio directly determines the amount and morphology of Mg2Si precipitation, the stability of solid solution strengthening and aging reactions, the distribution, size, and brittleness of grain boundary phases, and microstructure and texture evolution, ultimately affecting edge ductility and processing stability. The Mg to Si ratio specified in this invention, for example, 0.55% Mg and 0.50% Si, approximately equals a molar ratio of 1.73, close to the stoichiometric ratio of Mg2Si (Mg:Si = 1.73:1), favors the formation of a stable, dispersed strengthening phase and reduces residual Mg or Si segregation. Only a Mg / Si ratio close to the stoichiometric strengthening phase ensures: effective precipitation of fine, dispersed Mg2Si; avoids non-strengthening phases and segregation; improves edge ductility and processing stability in the T4P state; provides a good texture foundation, and inhibits the formation of unfavorable orientations.

[0020] In the present invention, the combination of a specific Mg to Si content ratio, low Fe, and an appropriate amount of Er / Sn enables the aluminum alloy plate to have excellent flanging performance and mechanical properties.

[0021] A second aspect of the present invention provides a method for preparing the high-performance hemmed 6-series aluminum alloy sheet, wherein the method comprises: Casting, homogenization treatment, hot rolling, cold rolling, continuous annealing; The homogenization treatment conditions include: 565-575°C × 4-8h.

[0022] In the present invention, Ti, Cr and Fe are combined with the above-mentioned specific high-temperature soaking, which can effectively promote the eutectic components to enter solid solution or precipitate in the form of spheroidization, effectively improving hot working plasticity and forming toughness.

[0023] The specific homogenization treatment of the present invention ensures that the aluminum alloy maintains a relatively uniform grain size distribution, further improving the material's structural stability and forming a more stable and uniform texture in the alloy. This precise temperature control helps control the growth and distribution of grains, thereby affecting the final texture formation.

[0024] In the present invention, the combination of hot rolling and cold rolling processes optimizes texture control. By controlling the thickness of the material after hot rolling, the total reduction rate of subsequent cold rolling is ensured to reach 70-80%, effectively promoting grain refinement and avoiding the formation of excessive unfavorable textures.

[0025] According to the present invention, the hot rolling conditions include: hot rolling final temperature of 390-410° C., hot rolling coiling temperature of 370-400° C., and hot rolling reduction rate of 98.5-99.5%.

[0026] In the present invention, the hot rolling process of the present invention is limited in the control of the final rolling temperature, coiling temperature and hot rolling reduction rate, ensuring the uniformity and refinement of the texture. Compared with conventional processes, the texture evolution is optimized, especially in improving the Cube texture ratio and avoiding Goss texture.

[0027] According to the present invention, the cold rolling conditions include: a cold rolling reduction rate of 70-80%, and a cold rolling speed of 30-80 m / min.

[0028] In the present invention, a specific cold rolling reduction ratio ensures the formation of sufficient recrystallization driving force, and the cold rolling speed is precisely controlled within the range of 30-80 m / min. The change in rolling speed directly affects the strain rate sensitivity (SRS) of the material. A lower rolling speed gradually reduces the strain rate of the material, avoiding the degradation of material properties under high strain rates. An excessively fast rolling speed, such as 110 m / min in conventional processes, may lead to an excessively high strain rate, which in turn leads to grain coarsening and uneven texture, and even increases local heat accumulation, affecting the final edge forming performance. During the cold rolling process, the rolling speed affects the fluidity of the metal. An excessively high rolling speed will cause uneven metal flow, resulting in structural instability and stress concentration, thereby affecting the ductility and hemming performance of the material. An excessively slow rolling speed may lead to excessive cooling, excessive grain refinement, or insufficient annealing, resulting in stress concentration and microcracks in the structure. The cold rolling speed has an important influence on the control of material texture. A lower rolling speed helps to increase the proportion of Cube texture, thereby improving the ductility of the material and reducing crack generation during edge forming. Excessively fast rolling speed may make the texture formation unstable, resulting in an excessively high proportion of unfavorable textures such as Goss texture. Such textures will cause stress concentration during the forming process and reduce edge performance.

[0029] According to the present invention, the cold rolling conditions further include: performing intermediate annealing when the plate thickness deformation reaches 30-55%, the intermediate annealing temperature is 380-430° C., and the intermediate annealing holding time is 4-6 hours.

[0030] In the present invention, the plate thickness deformation amount refers to the deformation amount of the plate thickness in the cold rolling process.

[0031] According to the present invention, the continuous annealing treatment includes solution heat treatment and pre-aging.

[0032] According to the present invention, the conditions of the solution heat treatment include: heating in a continuous air cushion furnace, a solution heat treatment temperature of 480-530° C., and a solution heat treatment holding time of 40-60 seconds.

[0033] In the present invention, the above-mentioned annealing temperature and annealing holding time can promote the recrystallization of the aluminum alloy, eliminate the stress concentration areas caused by excessive deformation during hot rolling or cold rolling, refine the grains, and enhance the ductility of the material. Through intermediate annealing, especially the suppression of Goss texture, a higher proportion of Cube texture formation is promoted. The Cube texture has a significant improvement effect on the hemming performance of the aluminum alloy, can distribute strain more evenly, and reduce the generation of cracks. The annealing process helps to release the internal stress accumulated in the material, improves the crack resistance of the material during the hemming forming process, and greatly enhances the edge ductility of the material.

[0034] The intermediate annealing process of the present invention forms a synergistic effect with the hot rolling, cold rolling and aging treatment processes to ensure that the performance improvement of the material is continuous at each stage. By controlling the final rolling temperature of the hot rolling process and the cold rolling reduction rate, the optimization of the grain and texture is achieved. The intermediate annealing further refines the grain and controls the texture by adjusting the temperature and holding time, thereby improving the final hemming performance.

[0035] According to the present invention, the conditions of the solution heat treatment include: heating in a continuous air cushion furnace, a solution heat treatment temperature of 540-555° C., and a solution heat treatment holding time of 30-40 seconds.

[0036] According to the present invention, the conditions of the solid solution heat treatment further include: cooling after the solid solution treatment, with a cooling rate of 250-450°C / min.

[0037] According to the present invention, the pre-aging conditions also include: the pre-aging system is 95-110° C.×4-12h.

[0038] In the present invention, the specific solution heat treatment conditions significantly increase the Cube texture ratio. The Cube texture helps to evenly distribute the strain of the material during the hemming forming process and reduce the generation of cracks. In the process of the present invention, rapid cooling ensures rapid passage through the precipitation sensitive zone, improves the solid solubility, and further reduces the formation of Goss texture, thereby improving the ductility and hemming performance of the material. The pre-aging system forms a stable T4P state microstructure.

[0039] The solution heat treatment of the present invention has the effects of rapid temperature rise, uniform heat transfer and high-efficiency solid solution. Combined with the low Si and Er microalloying and precision-controlled hot-rolled structure in the present invention, it can further improve the solid solubility of solute atoms and enhance the uniformity of Mg2Si precipitation, thereby improving the edge forming limit angle and edge crack resistance.

[0040] In the present invention, the melting and casting conditions may be in accordance with conventional melting and casting conditions in the art.

[0041] Test Method Tensile strength, tested in accordance with ISO6892-1; Yield strength, tested in accordance with ISO6892-1; Elongation after break, tested in accordance with ISO6892-1; Maximum plastic elongation (Ag), tested in accordance with ISO6892-1; Strain hardening index (n5), tested according to ISO10275; Plastic strain ratio (r5), tested according to ISO10113 90° (direction), tested in accordance with ISO6892-1; The hemming coefficient (f) is tested in accordance with GMW15421.

[0042] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the embodiments described herein are only some embodiments of the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments implemented by those of ordinary skill in the art without making creative improvements are within the scope of protection of the present invention.

[0043] Example 1 Casting: Prepare aluminum alloy plate raw materials according to the following weight proportions: Si: 0.5%, Fe: 0.11%, Cu: 0.15%, Mn: 0.10%, Mg: 0.55%, Cr: 0.05%, Ni: 0.003%, Zn: 0.002%, Ti: 0.03%, V: 0.003%, Zr: 0.04%, Sn: 0.01%, Er: 0.2%.

[0044] Homogenization treatment: After casting, the cast bars are homogenized at 570°C for 6 hours.

[0045] Hot rolling: The hot rolling process is 1 rough rolling plus 4 finishing rolling, the hot rolling final temperature is 400℃, the hot rolling coiling temperature is 385℃, and the hot rolling reduction rate is 99%.

[0046] Cold rolling: the cold rolling reduction rate is 75%, the cold rolling rate is 60m / min, the intermediate annealing temperature is 410℃, the intermediate annealing is carried out when the deformation reaches 45%, and the intermediate annealing holding time is 5h.

[0047] Solution heat treatment: adopt continuous air cushion furnace heating, solution heat treatment temperature is 545 ℃, solution heat treatment holding time is 35s, cooling is carried out after solution treatment, and cooling rate is 300 ℃ / min.

[0048] Pre-aging: The pre-aging system is 100℃ × 4h.

[0049] Finishing process.

[0050] An aluminum alloy plate A1 was obtained.

[0051] Example 2 An aluminum alloy plate was prepared according to the method of Example 1, except that the aluminum alloy components were Si: 0.45%, Fe: 0.07%, Cu: 0.13%, Mn: 0.08%, Mg: 0.50%, Cr: 0.04%, Ni: 0.002%, Zn: 0.001%, Ti: 0.02%, V: 0.001%, Zr: 0.04%, Sn: 0.005%, and Er: 0.17%.

[0052] An aluminum alloy plate A2 was obtained.

[0053] Example 3 An aluminum alloy plate was prepared according to the method of Example 1, except that the aluminum alloy components were Si: 0.55%, Fe: 0.15%, Cu: 0.17%, Mn: 0.12%, Mg: 0.60%, Cr: 0.06%, Ni: 0.02%, Zn: 0.10%, Ti: 0.04%, V: 0.02%, Zr: 0.06%, Sn: 0.015%, and Er: 0.23%.

[0054] An aluminum alloy plate A3 was obtained.

[0055] Example 4 An aluminum alloy plate was prepared according to the method of Example 1, except that the homogenization treatment was performed at 565°C for 4 h.

[0056] An aluminum alloy plate A4 is obtained.

[0057] Example 5 An aluminum alloy plate was prepared according to the method of Example 1, except that the homogenization treatment was performed at 575°C for 8 h.

[0058] An aluminum alloy plate A5 was obtained.

[0059] Example 6 An aluminum alloy plate was prepared according to the method of Example 1, except that the hot rolling final temperature was 370° C., the hot rolling coiling temperature was 390° C., and the hot rolling reduction ratio was 99.5%.

[0060] Aluminum alloy plate A6 was obtained.

[0061] Example 7 An aluminum alloy plate was prepared according to the method of Example 1, except that the hot rolling final temperature was 400° C., the hot rolling coiling temperature was 410° C., and the hot rolling reduction ratio was 98.5%.

[0062] An aluminum alloy plate A7 was obtained.

[0063] Example 8 An aluminum alloy plate was prepared according to the method of Example 1, except that the cold rolling reduction ratio was 70% and the cold rolling rate was 30 m / min.

[0064] An aluminum alloy plate A8 was obtained.

[0065] Example 9 An aluminum alloy plate was prepared according to the method of Example 1, except that the cold rolling reduction ratio was 80% and the cold rolling rate was 80 m / min.

[0066] An aluminum alloy plate A9 was obtained.

[0067] Example 10 An aluminum alloy plate was prepared according to the method of Example 1, except that the intermediate annealing temperature was 380° C., intermediate annealing was performed when the deformation amount reached 30%, and the intermediate annealing holding time was 4 h.

[0068] Aluminum alloy plate A10 was obtained.

[0069] Example 11 An aluminum alloy plate was prepared according to the method of Example 1, except that the intermediate annealing temperature was 430° C., intermediate annealing was performed when the deformation reached 55%, and the intermediate annealing holding time was 6 h.

[0070] An aluminum alloy plate A11 was produced.

[0071] Example 12 An aluminum alloy plate was prepared according to the method of Example 1, except that the solution heat treatment temperature was 540° C. and the solution heat treatment holding time was 40 s.

[0072] Aluminum alloy sheet A12 was obtained.

[0073] Example 13 An aluminum alloy plate was prepared according to the method of Example 1, except that the solution heat treatment temperature was 555° C. and the solution heat treatment holding time was 60 s.

[0074] Aluminum alloy plate A13 was obtained.

[0075] Example 14 An aluminum alloy plate was prepared according to the method of Example 1, except that the cooling rate was 260° C. / min.

[0076] Aluminum alloy plate A14 was produced.

[0077] Example 15 An aluminum alloy plate was prepared according to the method of Example 1, except that the cooling rate was 440° C. / min.

[0078] Aluminum alloy plate A15 was produced.

[0079] Example 16 An aluminum alloy plate was prepared according to the method of Example 1, except that the pre-aging system was 95° C.×4 h.

[0080] Aluminum alloy sheet A16 was obtained.

[0081] Example 17 An aluminum alloy plate was prepared according to the method of Example 1, except that the pre-aging system was 110° C.×12 h.

[0082] Aluminum alloy plate A17 was produced.

[0083] Comparative Example 1 An aluminum alloy plate was prepared according to the method of Example 1, except that the aluminum alloy components were Si: 0.41%, Fe: 0.10%, Cu: 0.10%, Mn: 0.05%, Mg: 0.49%, Cr: 0.02%, Ni: 0.004%, Zn: 0.001%, Ti: 0.01%, V: 0.002%, Zr: 0.002%, Sn: 0.001%, and Er: 0.001%.

[0084] An aluminum alloy plate DA1 was produced.

[0085] Comparative Example 2 An aluminum alloy plate was prepared according to the method of Example 1, except that the aluminum alloy components were Si: 0.58%, Fe: 0.11%, Cu: 0.21%, Mn: 0.15%, Mg: 0.63%, Cr: 0.08%, Ni: 0.003%, Zn: 0.001%, Ti: 0.05%, V: 0.02%, Zr: 0.25%, Sn: 0.02%, and Er: 0.25%.

[0086] An aluminum alloy plate DA2 was produced.

[0087] Comparative Example 3 An aluminum alloy plate was prepared according to the method of Example 1, except that the homogenization treatment was performed at 540°C for 3 h.

[0088] An aluminum alloy plate DA3 was produced.

[0089] Comparative Example 4 An aluminum alloy plate was prepared according to the method of Example 1, except that the homogenization treatment was performed at 580°C for 9 h.

[0090] Aluminum alloy sheet DA4 was produced.

[0091] Comparative Example 5 An aluminum alloy plate was prepared according to the method of Example 1, except that the hot rolling final temperature was 380° C., the hot rolling coiling temperature was 370° C., and the hot rolling reduction ratio was 99.6%.

[0092] Aluminum alloy sheet DA5 was produced.

[0093] Comparative Example 6 An aluminum alloy plate was prepared according to the method of Example 1, except that the hot rolling final temperature was 430° C., the hot rolling coiling temperature was 420° C., and the hot rolling reduction ratio was 98.4%.

[0094] Aluminum alloy sheet DA6 was produced.

[0095] Comparative Example 7 An aluminum alloy plate was prepared according to the method of Example 1, except that the cold rolling reduction ratio was 66.7% and the cold rolling rate was 28 m / min.

[0096] Aluminum alloy sheet DA7 was produced.

[0097] Comparative Example 8 An aluminum alloy plate was prepared according to the method of Example 1, except that the cold rolling reduction ratio was 81.8% and the cold rolling rate was 85 m / min.

[0098] An aluminum alloy plate A8 was obtained.

[0099] Comparative Example 9 An aluminum alloy plate was prepared according to the method of Example 1, except that the intermediate annealing temperature was 360° C., intermediate annealing was performed when the deformation amount reached 25%, and the intermediate annealing holding time was 3 h.

[0100] Aluminum alloy sheet DA9 was produced.

[0101] Comparative Example 10 An aluminum alloy plate was prepared according to the method of Example 1, except that the intermediate annealing temperature was 440° C., intermediate annealing was performed when the deformation amount reached 60%, and the intermediate annealing holding time was 8 h.

[0102] Aluminum alloy sheet DA10 was produced.

[0103] Comparative Example 11 An aluminum alloy plate was prepared according to the method of Example 1, except that the solution heat treatment temperature was 520° C. and the solution heat treatment holding time was 25 s.

[0104] Aluminum alloy sheet DA11 was produced.

[0105] Comparative Example 12 An aluminum alloy plate was prepared according to the method of Example 1, except that the solution heat treatment temperature was 560° C. and the solution heat treatment holding time was 45 s.

[0106] Aluminum alloy sheet DA12 was produced.

[0107] Comparative Example 13 An aluminum alloy plate was prepared according to the method of Example 1, except that the cooling rate was 200° C. / min.

[0108] Aluminum alloy sheet DA13 was produced.

[0109] Comparative Example 14 An aluminum alloy plate was prepared according to the method of Example 1, except that the cooling rate was 480° C. / min.

[0110] Aluminum alloy sheet DA14 was produced.

[0111] Comparative Example 15 An aluminum alloy plate was prepared according to the method of Example 1, except that the pre-aging system was 80° C.×3 h.

[0112] Aluminum alloy sheet DA15 was produced.

[0113] Comparative Example 16 An aluminum alloy plate was prepared according to the method of Example 1, except that the pre-aging system was 115° C.×15 h.

[0114] Aluminum alloy sheet DA16 was produced.

[0115] Comparative Example 17 An aluminum alloy plate was prepared according to the method of Example 1, except that the homogenization treatment was performed at 550° C. for 10 h.

[0116] Hot rolling: The hot rolling final temperature is 430℃, the hot rolling coiling temperature is 410℃, and the hot rolling reduction rate is 99%.

[0117] Cold rolling: the cold rolling reduction rate is 65%, the cold rolling rate is 50m / min, the intermediate annealing temperature is 380℃, and the intermediate annealing holding time is 4h.

[0118] Solution heat treatment: adopt continuous air cushion furnace heating, solution heat treatment temperature is 510℃, solution heat treatment holding time is 40s, cooling is carried out after solution treatment, and cooling rate is 350℃ / s.

[0119] Pre-aging: The pre-aging system is 80℃ × 8h.

[0120] Aluminum alloy sheet DA17 was produced.

[0121] Comparative Example 18 An aluminum alloy plate was prepared according to the method of Example 1, except that the aluminum alloy components were Si: 0.80%, Fe: 0.20%, Cu: 0.25%, Mn: 0.10%, Mg: 0.70%, Cr: 0.10%, Ni: 0.05%, Zn: 0.10%, Ti: 0.15%, V: 0.05%, and Zr: 0.10%.

[0122] Homogenization treatment: The homogenization treatment system is 550℃×10h.

[0123] Hot rolling: The hot rolling final temperature is 430℃, the hot rolling coiling temperature is 410℃, and the hot rolling reduction rate is 99%.

[0124] Cold rolling: the cold rolling reduction rate is 65%, the cold rolling rate is 50m / min, the intermediate annealing temperature is 380℃, and the intermediate annealing holding time is 4h.

[0125] Solution heat treatment: adopt continuous air cushion furnace heating, solution heat treatment temperature is 510 ℃, solution heat treatment holding time is 40s, cooling is carried out after solution treatment, and cooling rate is 350 ℃ / min.

[0126] Pre-aging: The pre-aging system is 80℃ × 8h.

[0127] Aluminum alloy sheet DA18 was produced.

[0128] Performance tests were conducted on A1-A17 and DA1-DA18, as shown in Table 1. Table 1 The direction in Table 1 refers to the direction of tensile specimen preparation. The tensile properties of automotive panels are usually evaluated in the 90° direction.

[0129] By comparing the examples with the comparative examples, it can be seen that the aluminum alloy plate provided by the present invention has excellent mechanical properties and flanging properties.

[0130] The present invention effectively achieves the coordinated control of microstructure refinement, texture uniformity and edge plasticity enhancement by microalloying 6014 alloy components (Er, Sn) and composition control, precise control of soaking and hot rolling temperatures, and optimization of cold rolling speed and annealing process. It can be seen from the comparative example 18 using the prior art that the alloy composition and process of the prior art cannot have both excellent mechanical properties and flanging performance. The present invention, on the basis of regulating the alloy composition, solves the problem of microstructure caused by the adjustment of the alloy composition, and the subsequent problems of uneven mechanical properties and the inability to have both mechanical properties and flanging performance.

[0131] Furthermore, Comparative Example 17 adopts the alloy composition of the present invention, but uses the conventional 6-series aluminum alloy preparation process of the prior art, and the obtained aluminum alloy plate still cannot have both excellent mechanical properties and flanging performance.

[0132] Attached to the instruction manual Figure 1-Figure 3 It can be seen that the indenter radius of the plate of Example 1 without cracking is smaller than the indenter radius of Comparative Examples 17 and 18 without cracking, indicating that the plate provided by the present invention has excellent flanging performance.

[0133] The above description is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A high-performance hemming-formed 6-series aluminum alloy sheet, characterized in that: The components and their weight percentages in the plate are: Si content is 0.45-0.55%; Fe content ≤ 0.15%; Cu content is 0.13-0.17%; Mn content is 0.08-0.12%; Mg content is 0.50-0.60%; Cr content is 0.04-0.06%; Ni content ≤ 0.02%; Zn content ≤ 0.10%; Ti content is 0.02-0.04%; V content ≤ 0.02%; Zr content is 0.04-0.06%; Sn content is 0.005-0.015%; Er content is 0.17-0.23%; The content of other impurity elements is ≤0.03%; The total content of other impurity elements is ≤0.1%; The remainder is Al; Among them, the ratio of Mg to Si content is 1:1-1.

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2. A method for preparing the high-performance hemmed-formed 6-series aluminum alloy sheet according to claim 1, characterized in that: The method comprises: Casting, homogenization, hot rolling, cold rolling, annealing, and finishing processes; The homogenization treatment conditions include: 565-575°C × 4-8h.

3. The method according to claim 2, characterized in that The hot rolling conditions include: hot rolling final temperature of 390-410° C., hot rolling coiling temperature of 370-400° C., and hot rolling reduction rate of 98.5-99.5%.

4. The method according to claim 2, characterized in that The cold rolling conditions include: a cold rolling reduction ratio of 70-80% and a cold rolling speed of 30-80 m / min.

5. The method according to claim 4, characterized in that The cold rolling conditions also include: performing intermediate annealing when the plate thickness deformation reaches 30-55%, the intermediate annealing temperature is 380-430° C., and the intermediate annealing holding time is 4-6 hours.

6. The method according to claim 2, characterized in that The continuous annealing treatment includes solution heat treatment and pre-aging; The conditions of the solution heat treatment include: heating in a continuous air cushion furnace, a solution heat treatment temperature of 540-555° C., and a solution heat treatment holding time of 30-40 seconds.

7. The method according to claim 6, characterized in that The conditions of the solution heat treatment also include: cooling after solutionizing, with a cooling rate of 250-450°C / min.

8. The method according to claim 6, characterized in that The pre-aging conditions also include: the pre-aging system is 95-110° C.×4-12h.

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