Aluminum alloy plate strip and preparation method thereof

Abstract

The invention provides an aluminum alloy plate strip and a preparation method thereof. The preparation method comprises the steps that an aluminum alloy cast ingot is sequentially subjected to homogenizing heat treatment, hot rolling treatment, first cold rolling treatment, first annealing treatment, second cold rolling treatment and second annealing treatment, and an aluminum alloy plate strip is obtained; wherein the air cushion furnace is adopted for second annealing treatment, the temperature of the second annealing treatment is larger than or equal to 350 DEG C, the time of the second annealing treatment is 5-300 s, and the tension of a rubber roller in the air cushion furnace is larger than or equal to 5 MPa. According to the annealing process of the air cushion furnace, the aluminum alloy plate strip can be rapidly and uniformly heated, so that the problem of inconsistent grain growth caused by temperature difference is favorably reduced, and the thickness uniformity of the aluminum alloy plate strip after stamping and thinning is improved. The tension of the rubber roller is controlled to be larger than or equal to 5 MPa, the flatness of the surface of the aluminum alloy plate strip can be improved, and therefore the defects caused by surface microcosmic unevenness in the cold rolling stage are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to an aluminum alloy plate and strip material and a preparation method thereof. Background Art

[0002] With the continuous development of new energy electric vehicles, 3C electronic products and other fields, the market for lithium-ion batteries continues to grow. Aluminum has the advantages of low density, corrosion resistance, formability, and good welding performance, so aluminum alloys are widely used in new energy products. The aluminum alloy strip of the explosion-proof plate for lithium-ion batteries is first prepared into an explosion-proof valve of the required shape and size through a punching process, and then welded to the battery cover. Finally, the cover and the shell are welded together to form the main battery container. During operation, when the pressure inside the battery increases, it will be disconnected in time at the engraved line of the explosion-proof plate, which improves the overall safety performance of the battery pack.

[0003] The explosion-proof disc on the battery cover is an important part of the battery, so the stability of the explosion-proof valve's bursting pressure is strictly required. The thickness of the arched part of the common explosion-proof disc varies from 100 to 200 μm. The existing explosion-proof disc strip has a slight alternating thickness and thickness fluctuation defect after punching. The defect is visually observed to be a stripe color difference morphology, which has an adverse effect on the stability of the explosion-proof disc's bursting pressure.

[0004] The stability of bursting pressure is an important performance index requirement of explosion-proof plates. For this reason, the Chinese patent application with patent application number 201210588556.8 discloses a lithium-ion battery aluminum alloy explosion-proof plate, and its solution involves adding rare earth elements to Al-Mg-Mn alloy to refine grains and improve the uniformity of phases to ensure the stability of the product's bursting pressure. The Chinese patent application with patent application number 201010573300.0 discloses an aluminum alloy plate for battery cover and a manufacturing method thereof, which improves the bursting pressure stability of the explosion-proof part of the explosion-proof plate by adjusting the alloy composition and annealing by rapid heating and rapid cooling. The Chinese patent application with patent application number 201710697977.7 discloses an aluminum alloy strip for explosion-proof valves of new energy battery covers and a preparation method thereof, which ensures the problem of bursting pressure stability of the explosion-proof part of the explosion-proof plate by adjusting the alloy composition and producing an aluminum alloy strip obtained by ordinary box-type annealing furnace. However, none of these patent applications proposes a solution to the defect of alternating thickness after the explosion-proof plate is punched and thinned. Summary of the invention

[0005] The main purpose of the present invention is to provide an aluminum alloy plate and strip and a preparation method thereof, so as to solve the problem in the prior art that stripes appear on the surface of the aluminum alloy plate and strip after being punched and thinned.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided a method for preparing an aluminum alloy sheet and strip, the preparation method comprising: subjecting an aluminum alloy ingot to a homogenization heat treatment, a hot rolling treatment, a first cold rolling treatment, a first annealing treatment, a second cold rolling treatment, and a second annealing treatment in sequence to obtain an aluminum alloy sheet and strip; wherein, an air cushion furnace is used for the second annealing treatment, the temperature of the second annealing treatment is ≥350°C, the time of the second annealing treatment is 5s to 300s, and the tension of the rubber roller in the air cushion furnace is ≥5MPa.

[0007] Further, the temperature of the second annealing treatment is 350-550° C.; and / or, the time of the second annealing treatment is 10s-100s; and / or, the tension of the rubber roller in the air cushion furnace is 10-60MPa.

[0008] Furthermore, the rolling processing rate of each pass in the above-mentioned hot rolling treatment is 10% to 60%, preferably 20% to 40%; and / or the total processing rate of the hot rolling treatment is ≥80%, preferably 98.0% to 98.5%; and / or the temperature at the end of the hot rolling treatment is ≥280°C, preferably 300°C to 330°C; and / or the thickness of the hot-rolled plate obtained by the hot rolling treatment is 5.0 to 8.0 mm, preferably 5.0 to 7.5 mm.

[0009] Furthermore, the rolling processing rate of each pass in the above-mentioned first cold rolling treatment is 20% to 50%, preferably 20% to 40%; and / or the total processing rate of the first cold rolling treatment is ≥30%, preferably 58.3% to 73.3%; and / or the thickness of the first cold rolled plate obtained by the first cold rolling treatment is 1.5 to 4.0 mm, preferably 2.0 to 3.0 mm.

[0010] Furthermore, the rolling processing rate of each pass in the above-mentioned second cold rolling treatment is 10% to 40%, preferably 20% to 33%; and / or the total processing rate of the second cold rolling treatment is ≥50%, preferably 75% to 86.7%; and / or the thickness of the second cold rolled plate obtained by the second cold rolling treatment is 0.1 to 1.0 mm, preferably 0.4 to 0.5 mm.

[0011] Furthermore, the average roughness of the roll in the first cold rolling process is 0.20 to 0.46 μm, preferably 0.30 to 0.35 μm; and / or the average roughness of the roll in the second cold rolling process is 0.10 to 0.20 μm, preferably 0.10 to 0.15 μm.

[0012] Furthermore, the temperature of the first annealing treatment is ≥300°C, preferably 350-500°C; and / or the holding time of the first annealing treatment is 1-10h, preferably 1-5h; and / or the temperature of the homogenization heat treatment is 600-610°C; and / or the holding time of the homogenization heat treatment is 8-20h.

[0013] Furthermore, the above-mentioned aluminum alloy ingot is selected from any one or more of 8006 aluminum alloy ingot, 8007 aluminum alloy ingot, 8008 aluminum alloy ingot, 8011 aluminum alloy ingot, 8021 aluminum alloy ingot, 8014 aluminum alloy ingot, 8050 aluminum alloy ingot, 8211 aluminum alloy ingot, 8023 aluminum alloy ingot and 8026 aluminum alloy ingot.

[0014] According to another aspect of the present invention, an aluminum alloy plate and strip is provided. The aluminum alloy plate and strip is prepared by the aforementioned preparation method.

[0015] Furthermore, in terms of volume fraction, the proportion of Cube texture in the above-mentioned aluminum alloy sheet and strip is ≤10%, the proportion of Goss texture is ≤10%, the proportion of R texture is ≤20%, and the proportion of S texture is ≤15%; and / or the surface roughness of the aluminum alloy sheet and strip is 0.16~0.19μm; and / or the average grain size in the aluminum alloy sheet and strip is 6μm~14μm; and / or the tensile strength of the aluminum alloy sheet and strip is ≥105MPa, the yield strength is ≥45MPa, and the elongation is ≥37%.

[0016] By applying the technical solution of the present invention, the present application helps to reduce the size of the grains through hot rolling treatment, the first cold rolling treatment and the second cold rolling treatment, and helps to control the proportion of recrystallization texture and deformation texture and improve the uniformity of the distribution of recrystallization texture and deformation texture through the first annealing treatment and the second annealing treatment, thereby helping to weaken the influence of the high aggregation of texture on the formability of aluminum alloy sheet and strip, so that the mechanical properties of the aluminum alloy sheet and strip are still maintained without reducing the punching performance of the aluminum alloy sheet and strip. The annealing process of the air cushion furnace can heat the aluminum alloy sheet and strip quickly and evenly, avoiding the problem of uneven heating that may occur during the annealing process of the traditional box furnace, thereby helping to reduce the problem of inconsistent grain growth caused by temperature differences, and improving the thickness uniformity of the aluminum alloy sheet and strip after stamping and thinning. By controlling the tension of the rubber roller ≥5MPa, it helps to improve the flatness of the surface of the aluminum alloy sheet and strip, thereby reducing the defects caused by the microscopic unevenness of the surface during the cold rolling stage. Controlling the temperature and time of the second annealing treatment within the above ranges helps to form a more uniform grain structure, thereby improving the tensile strength, yield strength and elongation of the aluminum alloy sheet and strip. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 An optical photograph of the aluminum alloy plate and strip after punching and thinning in Example 1 of the present application is shown;

[0019] Figure 2 An optical photograph of the aluminum alloy sheet and strip after punching and thinning in Comparative Example 1 of the present application is shown. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] As analyzed in the background technology of this application, there is a problem in the prior art that stripes appear on the surface of aluminum alloy plates and strips after punching and thinning. In order to solve the above problem, this application provides an aluminum alloy plate and strip and a preparation method thereof.

[0022] It should be noted that the Cube texture is a texture in which the {001} crystal plane of the grain is parallel to the rolling plane, and the

[100] crystal direction is parallel to the rolling direction, the Goss texture is a texture in which the {110} crystal plane of the grain is parallel to the rolling plane, and the

[001] crystal direction is parallel to the rolling direction, the R texture is a texture in which the {124} crystal plane of the grain is parallel to the rolling plane, and the

[211] crystal direction is parallel to the rolling direction, and the S texture is a texture in which the {123} crystal plane of the grain is parallel to the rolling plane, and the

[634] crystal direction is parallel to the rolling direction.

[0023] In a typical embodiment of the present application, a method for preparing an aluminum alloy sheet and strip is provided, the preparation method comprising: subjecting an aluminum alloy ingot to a homogenization heat treatment, a hot rolling treatment, a first cold rolling treatment, a first annealing treatment, a second cold rolling treatment, and a second annealing treatment in sequence to obtain an aluminum alloy sheet and strip; wherein an air cushion furnace is used for the second annealing treatment, the temperature of the second annealing treatment is ≥350°C, the time of the second annealing treatment is 5s to 300s, and the tension of the rubber roller in the air cushion furnace is ≥5MPa.

[0024] The present application helps to reduce the size of the grains through hot rolling treatment, the first cold rolling treatment and the second cold rolling treatment, and helps to control the proportion of recrystallization texture and deformation texture and improve the uniformity of the distribution of recrystallization texture and deformation texture through the first annealing treatment and the second annealing treatment, thereby helping to weaken the influence of the high aggregation of texture on the formability of the aluminum alloy sheet and strip, so that the mechanical properties of the aluminum alloy sheet and strip are still maintained without reducing the punching performance of the aluminum alloy sheet and strip. The annealing process of the air cushion furnace can quickly and evenly heat the aluminum alloy sheet and strip, avoiding the problem of uneven heating that may occur during the annealing process of the traditional box furnace, thereby helping to reduce the problem of inconsistent grain growth caused by temperature differences, and improving the thickness uniformity of the aluminum alloy sheet and strip after stamping and thinning. By controlling the tension of the rubber roller ≥5MPa, it helps to improve the flatness of the surface of the aluminum alloy sheet and strip, thereby reducing the defects caused by the microscopic unevenness of the surface in the cold rolling stage. Controlling the temperature and time of the second annealing treatment within the above range helps to form a more uniform grain structure, thereby improving the tensile strength, yield strength and elongation of the aluminum alloy sheet and strip.

[0025] In order to further optimize the thickness uniformity, surface roughness and mechanical properties of aluminum alloy sheets and strips, thereby improving the punching performance of aluminum alloy sheets and strips, in one embodiment of the present application, the temperature of the second annealing treatment is preferably 350-550°C; and / or the time of the second annealing treatment is 10s-100s; and / or the tension of the rubber roller in the air cushion furnace is 10-60MPa.

[0026] In one embodiment of the present application, the rolling processing rate of each pass in the above-mentioned hot rolling treatment is 10% to 60%, preferably 20% to 40%; and / or the total processing rate of the hot rolling treatment is ≥80%, preferably 98.0% to 98.5%; and / or the temperature at the end of the hot rolling treatment is ≥280°C, preferably 300°C to 330°C; and / or the thickness of the hot-rolled plate obtained by the hot rolling treatment is 5.0 to 8.0 mm, preferably 5.0 to 7.5 mm.

[0027] It is preferred to control the rolling processing rate of each pass in the hot rolling process within the above range, which helps to control the degree of grain refinement and optimize the texture of the material, reduce the formation of strong texture, thereby helping to improve the isotropy of the material, and then improve the thickness uniformity of the aluminum alloy plate and strip after punching. It is preferred to control the total processing rate and temperature of the hot rolling process within the above range, which helps to eliminate casting defects and improve the microstructure and organizational uniformity of the material. It is preferred to control the thickness of the hot rolled plate within the above range, which helps to maintain good processability and performance in subsequent processing.

[0028] In one embodiment of the present application, the rolling processing rate of each pass in the above-mentioned first cold rolling treatment is 20% to 50%, preferably 20% to 40%; and / or, the total processing rate of the first cold rolling treatment is ≥30%, preferably 58.3% to 73.3%; and / or, the thickness of the first cold rolled plate obtained by the first cold rolling treatment is 1.5 to 4.0 mm, preferably 2.0 to 3.0 mm.

[0029] By controlling the processing rate of each pass of the first cold rolling treatment, the total processing rate and the thickness of the first cold rolled plate within the above range, it is helpful to regulate the microstructure of the material, including the texture distribution and grain size, thereby helping to significantly improve the punching performance and surface quality of the material without reducing the mechanical properties.

[0030] In one embodiment of the present application, the rolling processing rate of each pass in the above-mentioned second cold rolling treatment is 10% to 40%, preferably 20% to 33%; and / or, the total processing rate of the second cold rolling treatment is ≥50%, preferably 75% to 86.7%; and / or, the thickness of the second cold rolled plate obtained by the second cold rolling treatment is 0.1 to 1.0 mm, preferably 0.4 to 0.5 mm.

[0031] By controlling the processing rate of each pass of the second cold rolling treatment, the total processing rate and the thickness of the second cold rolled plate within the above-mentioned range, it helps to further optimize the grain size, texture distribution and surface roughness of the aluminum alloy sheet and strip, thereby helping to improve the mechanical properties and stamping properties of the aluminum alloy sheet and strip.

[0032] In one embodiment of the present application, the average roughness of the rolling mill in the first cold rolling treatment is 0.20 to 0.46 μm, preferably 0.30 to 0.35 μm; and / or the average roughness of the rolling mill in the second cold rolling treatment is 0.10 to 0.20 μm, preferably 0.10 to 0.15 μm.

[0033] By regulating the roughness of the rolls during the cold rolling process, the waviness of the surface of the plate and strip and the thickness tolerance accuracy of the strip can be affected, thereby affecting the rheological uniformity of the material during the product punching process, as well as the thickness waviness of the product components after punching. It is preferred to control the average roughness of the rolls in the first cold rolling process and the average roughness of the rolls in the second cold rolling process within the above range, which helps to reduce the surface waviness and thickness tolerance of the plate and strip, thereby helping to improve the dimensional stability of the aluminum alloy plate and strip after punching, reduce thickness fluctuations, and improve the overall performance of the product. A higher roll roughness in the first cold rolling process helps to reduce the roughness of the plate and strip in the second cold rolling process and improve the overall uniformity of the thickness, while a lower roll roughness in the second cold rolling process is conducive to forming a plate and strip with a more uniform thickness in the final forming stage, thereby helping to improve the mechanical properties and punching performance of the aluminum alloy plate and strip.

[0034] In one embodiment of the present application, the temperature of the first annealing treatment is ≥300°C, preferably 350-500°C; and / or the holding time of the first annealing treatment is 1-10h, preferably 1-5h; and / or the temperature of the homogenization heat treatment is 600-610°C; and / or the holding time of the homogenization heat treatment is 8-20h.

[0035] The main purpose of the first annealing treatment is to eliminate the work hardening produced during the first cold rolling treatment, promote the recrystallization of grains, and adjust the texture to improve the forming properties of the material. It is preferred to control the temperature and time of the first annealing treatment within the above range, which helps to reduce the high aggregation of the texture, thereby helping to improve the uniformity and stability of the material in the subsequent punching process. The purpose of the homogenization heat treatment is to improve the uniformity of the alloy composition and microstructure in the material. It is preferred to control the temperature and time of the homogenization heat treatment within the above range, which helps to further promote the diffusion of alloy elements, refine and homogenize grains, eliminate component segregation, and thus help to improve the consistency of material properties in subsequent processing.

[0036] In one embodiment of the present application, the above-mentioned aluminum alloy ingot is selected from any one or more of 8006 aluminum alloy ingot, 8007 aluminum alloy ingot, 8008 aluminum alloy ingot, 8011 aluminum alloy ingot, 8021 aluminum alloy ingot, 8014 aluminum alloy ingot, 8050 aluminum alloy ingot, 8211 aluminum alloy ingot, 8023 aluminum alloy ingot and 8026 aluminum alloy ingot.

[0037] The aluminum alloy sheet and strip prepared by the preparation method of the present application using the above-mentioned type of aluminum alloy ingot has better mechanical properties and punching properties, so that the surface quality of the aluminum alloy sheet and strip is good after punching and thinning.

[0038] In another typical embodiment of the present application, an aluminum alloy plate and strip is provided. The aluminum alloy plate and strip is prepared by the aforementioned preparation method.

[0039] The aluminum alloy sheet and strip prepared by the preparation method of the present application has good mechanical properties and punching properties, and no stripes with uneven thickness appear on the surface of the aluminum alloy sheet and strip after punching and thinning.

[0040] In one embodiment of the present application, in terms of volume fraction, the proportion of Cube texture in the aluminum alloy sheet and strip is ≤10%, the proportion of Goss texture is ≤10%, the proportion of R texture is ≤20%, and the proportion of S texture is ≤15%; and / or the surface roughness of the aluminum alloy sheet and strip is 0.16-0.19 μm; and / or the average grain size in the aluminum alloy sheet and strip is 6 μm-14 μm; and / or the tensile strength of the aluminum alloy sheet and strip is ≥105 MPa, the yield strength is ≥45 MPa, and the elongation is ≥37%.

[0041] After the aluminum alloy sheet and strip having the above characteristics is punched and thinned, no stripes of uneven thickness appear on its surface.

[0042] The beneficial effects of the present application will be further illustrated below in conjunction with embodiments.

[0043] Example 1

[0044] Step S1, subjecting the 8007 aluminum alloy ingot to homogenization heat treatment at 600° C. for 8 hours to obtain a homogenized aluminum alloy ingot;

[0045] Step S2, hot rolling the homogenized aluminum alloy ingot, with a rolling processing rate of 30%±5% for each pass, a total processing rate of 98%, and a final temperature of 305° C. to obtain a hot-rolled plate with a thickness of 7.5 mm;

[0046] Step S3: subjecting the hot-rolled aluminum sheet to a first cold rolling process, wherein the rolling processing rate of each pass is 25%±5%, the total processing rate is 60%, the average roughness of the rolling roller in the cold rolling is 0.30 μm, and a first cold-rolled sheet with a thickness of 3 mm is obtained;

[0047] Step S4: performing a first annealing treatment on the first cold-rolled sheet at a temperature of 500° C. for 1 hour to obtain a first annealed aluminum material;

[0048] Step S5: subjecting the first annealed aluminum material to a second cold rolling process, wherein the rolling processing rate of each pass is 25%±5%, the total processing rate is 83%, the average roughness of the rollers in the cold rolling is 0.10 μm, and a second cold rolled sheet with a thickness of 0.5 mm is obtained;

[0049] Step S6: subjecting the second cold-rolled sheet to a second annealing treatment and straightening in an air cushion furnace to obtain an aluminum alloy sheet strip. The second annealing treatment is performed at a temperature of 450° C. for 60 seconds, and the tension of the rubber roller is 10 MPa.

[0050] Example 2

[0051] Step S1, subjecting the 8021 aluminum alloy ingot to homogenization heat treatment at 605° C. for 12 hours to obtain a homogenized aluminum alloy ingot;

[0052] Step S2, hot rolling the homogenized aluminum alloy ingot, with a rolling processing rate of 35%±5% for each pass, a total processing rate of 98.3%, and a finishing temperature of 320° C. to obtain a hot-rolled plate with a thickness of 6.0 mm;

[0053] Step S3: subjecting the hot-rolled aluminum sheet to a first cold rolling process, wherein the rolling processing rate of each pass is 25%±5%, the total processing rate is 58.3%, the average roughness of the rollers in the cold rolling is 0.35 μm, and a first cold-rolled sheet with a thickness of 2.5 mm is obtained;

[0054] Step S4: performing a first annealing treatment on the first cold-rolled sheet at a temperature of 450° C. for 2 hours to obtain a first annealed aluminum material;

[0055] Step S5: subjecting the first annealed aluminum material to a second cold rolling process, wherein the rolling processing rate of each pass is 28%±5%, the total processing rate is 84%, the average roughness of the rollers in the cold rolling is 0.15 μm, and a second cold rolled sheet with a thickness of 0.4 mm is obtained;

[0056] Step S6: subjecting the second cold-rolled sheet to a second annealing treatment and straightening in an air cushion furnace to obtain an aluminum alloy sheet strip. The second annealing treatment is performed at a temperature of 350° C. for 100 s and a tension of the rubber roller of 60 MPa.

[0057] Example 3

[0058] Step S1, subjecting the 8050 aluminum alloy ingot to a homogenization heat treatment at 610° C. for 20 hours to obtain a homogenized aluminum alloy ingot;

[0059] Step S2, hot rolling the homogenized aluminum alloy ingot, with a rolling processing rate of 25%±5% for each pass, a total processing rate of 98.5%, and a finishing temperature of 325° C. to obtain a hot-rolled plate with a thickness of 5.0 mm;

[0060] Step S3: subjecting the hot-rolled aluminum sheet to a first cold rolling process, wherein the rolling processing rate of each pass is 30%±5%, the total processing rate is 60%, the average roughness of the rollers in the cold rolling is 0.32 μm, and a first cold-rolled sheet with a thickness of 2 mm is obtained;

[0061] Step S4: performing a first annealing treatment on the first cold-rolled sheet at a temperature of 350° C. for 5 hours to obtain a first annealed aluminum material;

[0062] Step S5: subjecting the first annealed aluminum material to a second cold rolling process, wherein the rolling processing rate of each pass is 25%±5%, the total processing rate is 75%, the average roughness of the rollers in the cold rolling is 0.15 μm, and a second cold rolled sheet with a thickness of 0.5 mm is obtained;

[0063] Step S6: subjecting the second cold-rolled sheet to a second annealing treatment and straightening in an air cushion furnace to obtain an aluminum alloy sheet strip. The temperature of the second annealing treatment is 550° C., the time is 10 s, and the tension of the rubber roller is 36 MPa.

[0064] Example 4

[0065] The difference from Example 1 is that the temperature of the second annealing treatment is 350° C., the time of the second annealing treatment is 100 s, the tension of the rubber roller in the air cushion furnace is 10 MPa, and finally an aluminum alloy sheet and strip is obtained.

[0066] Example 5

[0067] The difference from Example 1 is that the temperature of the second annealing treatment is 550° C., the time of the second annealing treatment is 10 s, the tension of the rubber roller in the air cushion furnace is 60 MPa, and finally an aluminum alloy sheet and strip is obtained.

[0068] Example 6

[0069] The difference from Example 1 is that the temperature of the second annealing treatment is 350° C., the time of the second annealing treatment is 300 s, the tension of the rubber roller in the air cushion furnace is 5 MPa, and finally an aluminum alloy sheet and strip is obtained.

[0070] Example 7

[0071] The difference from Example 1 is that the rolling processing rate of each pass in the hot rolling process is 25%±5%, the total processing rate of the hot rolling process is 98.5%, the temperature at the end of the hot rolling process is 330°C, the thickness of the hot rolled plate is 5.0 mm, and finally an aluminum alloy plate and strip is obtained.

[0072] Example 8

[0073] The difference from Example 1 is that the rolling processing rate of each pass in the hot rolling process is 15%±5%, the total processing rate of the hot rolling process is 80%, the temperature at the end of the hot rolling process is 280°C, the thickness of the hot rolled plate is 8.0 mm, and finally an aluminum alloy plate and strip is obtained.

[0074] Example 9

[0075] The difference from Example 1 is that the rolling processing rate of each pass in the hot rolling process is 25%±5%, the total processing rate of the hot rolling process is 80%, the temperature at the end of the hot rolling process is 270°C, the thickness of the hot rolled plate is 8.0 mm, and finally an aluminum alloy plate and strip is obtained.

[0076] Example 10

[0077] The difference from Example 1 is that the rolling processing rate of each pass in the first cold rolling treatment is 35%±5%, the total processing rate of the first cold rolling treatment is 73.3%, the thickness of the first cold rolled plate is 2.0 mm, and finally an aluminum alloy plate and strip is obtained.

[0078] Embodiment 11

[0079] The difference from Example 1 is that the rolling processing rate of each pass in the first cold rolling treatment is 25%±5%, the total processing rate of the first cold rolling treatment is 46.7%, the thickness of the first cold rolled plate is 4.0 mm, and finally an aluminum alloy plate and strip is obtained.

[0080] Example 12

[0081] The difference from Example 1 is that the rolling processing rate of each pass in the second cold rolling treatment is 28%±5%, the total processing rate of the second cold rolling treatment is 86.7%, the thickness of the second cold rolled plate is 0.4 mm, and finally an aluminum alloy plate and strip is obtained.

[0082] Example 13

[0083] The difference from Example 1 is that the rolling processing rate of each pass in the second cold rolling treatment is 15%±5%, the total processing rate of the second cold rolling treatment is 96.6%, the thickness of the second cold rolled plate is 0.1 mm, and finally an aluminum alloy plate and strip is obtained.

[0084] Embodiment 14

[0085] The difference from Example 1 is that the average roughness of the roller in the first cold rolling process is 0.35 μm, and the average roughness of the roller in the second cold rolling process is 0.15 μm, and finally an aluminum alloy sheet and strip is obtained.

[0086] Embodiment 15

[0087] The difference from Example 1 is that the average roughness of the roller in the first cold rolling process is 0.20 μm, and the average roughness of the roller in the second cold rolling process is 0.10 μm, and finally an aluminum alloy sheet and strip is obtained.

[0088] Example 16

[0089] The difference from Example 1 is that the average roughness of the roller in the first cold rolling process is 0.46 μm, and the average roughness of the roller in the second cold rolling process is 0.20 μm, and finally an aluminum alloy sheet and strip is obtained.

[0090] Embodiment 17

[0091] The difference from Example 1 is that the average roughness of the roller in the first cold rolling process is 0.50 μm, and the average roughness of the roller in the second cold rolling process is 0.30 μm, and finally an aluminum alloy sheet and strip is obtained.

[0092] Embodiment 18

[0093] The difference from Example 1 is that the temperature of the first annealing treatment is 350° C., the holding time of the first annealing treatment is 5 hours, and finally an aluminum alloy sheet strip is obtained.

[0094] Embodiment 19

[0095] The difference from Example 1 is that the temperature of the first annealing treatment is 300° C., the holding time of the first annealing treatment is 10 h, and finally an aluminum alloy sheet and strip is obtained.

[0096] Comparative Example 1

[0097] Step S1, subjecting the 8007 aluminum alloy ingot to a homogenization heat treatment at 620° C. for 20 hours to obtain a homogenized aluminum alloy ingot;

[0098] Step S2, hot rolling the homogenized aluminum alloy ingot, with a rolling processing rate of 32%±5% for each pass, a total processing rate of 98.4%, and a hot rolling end temperature of 380° C. to obtain a hot rolled plate with a thickness of 8.0 mm;

[0099] Step S3: subjecting the hot-rolled aluminum sheet to a first cold rolling process, wherein the rolling processing rate of each pass is 30%±5%, the total processing rate is 81.3%, the average roughness of the rollers in the cold rolling is 0.48 μm, and a first cold-rolled sheet with a thickness of 1.5 mm is obtained;

[0100] Step S4: performing a first annealing treatment on the first cold-rolled sheet at a temperature of 380° C. for 4 hours to obtain a first annealed aluminum material;

[0101] Step S5: subjecting the first annealed aluminum material to a second cold rolling process, wherein the rolling processing rate of each pass is 25%±5%, the total processing rate is 66.6%, the average roughness of the rollers in the cold rolling is 0.25 μm, and a second cold rolled sheet with a thickness of 0.5 mm is obtained;

[0102] Step S6: subjecting the second cold-rolled sheet to a second annealing treatment and straightening in a box-type annealing furnace to obtain an aluminum alloy sheet strip. The temperature of the second annealing treatment is 340° C. and the time is 4 hours.

[0103] Comparative Example 2

[0104] Step S1, subjecting the 8007 aluminum alloy ingot to homogenization heat treatment at 590° C. for 12 hours to obtain a homogenized aluminum alloy ingot;

[0105] Step S2, hot rolling the homogenized aluminum alloy ingot, with a rolling processing rate of 40%±5% for each pass, a total processing rate of 88%, and a hot rolling end temperature of 270° C. to obtain a hot rolled plate with a thickness of 6.5 mm;

[0106] Step S3: cold rolling the hot-rolled aluminum sheet, with a rolling processing rate of 30%±5% for each pass, a total processing rate of 92.3%, an average roughness of the rollers in the cold rolling process of 0.35 μm, and a cold-rolled sheet with a thickness of 0.5 mm obtained;

[0107] Step S4: annealing the cold-rolled sheet in a box-type annealing furnace at 320° C. for 6 hours to obtain an aluminum alloy sheet strip.

[0108] Comparative Example 3

[0109] The difference from Example 1 is that the second annealing treatment is carried out in a box-type annealing furnace, the temperature of the second annealing treatment is 340° C., and the time is 10 minutes, and finally an aluminum alloy sheet strip is obtained.

[0110] Comparative Example 4

[0111] The difference from Example 1 is that after the second cold rolling treatment, no second annealing treatment is performed to obtain an aluminum alloy sheet and strip.

[0112] Performance Testing

[0113] Texture ratio test: GB / T19501-2013 "General Rules for Microbeam Analysis Electron Backscatter Diffraction Analysis Method", texture ratio is measured by volume fraction.

[0114] Surface roughness test: Use SENSOFAR optical profiler to measure surface profile, roughness, surface defects and other surface morphological characteristics of various products, components and materials. The test environment temperature is 10℃~35℃. After the measurement, use SensoView software to obtain the surface roughness.

[0115] Test of average grain size: GB / T6394-2017 "Method for determination of average grain size of metals".

[0116] Testing of tensile strength, yield strength and elongation of aluminum alloy plates and strips: GB / T228.1-2021 "Tensile testing of metallic materials Part 1: Room temperature test method".

[0117] The aluminum alloy plates and strips prepared in the examples and comparative examples were tested for texture ratio, surface roughness, average grain size, tensile strength, yield strength and elongation. The test results are shown in Table 1.

[0118] The aluminum alloy plates and strips prepared in the examples and comparative examples were punched and thinned, and their surfaces were observed to see whether there were streaks. The results are shown in Table 2.

[0119] Table 1

[0120]

[0121]

[0122] Table 2

[0123]

[0124] Figure 1 This is an optical photograph of the aluminum alloy strip after punching and thinning in Example 1 of the present application. Figure 1 It can be seen that there are no stripes on the surface of the aluminum alloy sheet and strip.

[0125] Figure 2 This is an optical photograph of the aluminum alloy strip after punching and thinning in Comparative Example 1 of the present application. Figure 2 It can be seen that vertical stripes appear on the surface of the aluminum alloy sheet and strip.

[0126] As can be seen from Table 1 and Table 2, the proportion of Cube texture in the aluminum alloy sheet and strip in the embodiment is ≤10%, the proportion of Goss texture is ≤10%, the proportion of R texture is ≤20%, the proportion of S texture is ≤15%, the surface roughness of the aluminum alloy sheet and strip is in the range of 0.16-0.19 μm, the average grain size in the aluminum alloy sheet and strip is in the range of 6 μm-14 μm, the tensile strength of the aluminum alloy sheet and strip is ≥105 MPa, the yield strength is ≥45 MPa, and the elongation is ≥37%. Although there is no significant difference in tensile strength, yield strength and elongation between the embodiment and the comparative example, there are significant differences in the proportion of Cube texture, the proportion of Goss texture, the proportion of R texture, the proportion of S texture, the surface roughness and the average grain size between the embodiment and the comparative example, indicating that the factors affecting the surface stripes of the aluminum alloy sheet and strip are related to the proportion of Cube texture, the proportion of Goss texture, the proportion of R texture, the proportion of S texture, the surface roughness and the average grain size.

[0127] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0128] The present application helps to reduce the size of the grains through hot rolling treatment, the first cold rolling treatment and the second cold rolling treatment, and helps to control the proportion of recrystallization texture and deformation texture and improve the uniformity of the distribution of recrystallization texture and deformation texture through the first annealing treatment and the second annealing treatment, thereby helping to weaken the influence of the high aggregation of texture on the formability of the aluminum alloy sheet and strip, so that the mechanical properties of the aluminum alloy sheet and strip are still maintained without reducing the punching performance of the aluminum alloy sheet and strip. The annealing process of the air cushion furnace can quickly and evenly heat the aluminum alloy sheet and strip, avoiding the problem of uneven heating that may occur during the annealing process of the traditional box furnace, thereby helping to reduce the problem of inconsistent grain growth caused by temperature differences, and improving the thickness uniformity of the aluminum alloy sheet and strip after stamping and thinning. By controlling the tension of the rubber roller ≥5MPa, it helps to improve the flatness of the surface of the aluminum alloy sheet and strip, thereby reducing the defects caused by the microscopic unevenness of the surface in the cold rolling stage. Controlling the temperature and time of the second annealing treatment within the above range helps to form a more uniform grain structure, thereby improving the tensile strength, yield strength and elongation of the aluminum alloy sheet and strip.

[0129] The above are only embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an aluminum alloy plate and strip, characterized in that: The preparation method comprises: The aluminum alloy ingot is subjected to homogenization heat treatment, hot rolling treatment, first cold rolling treatment, first annealing treatment, second cold rolling treatment and second annealing treatment in sequence to obtain the aluminum alloy plate and strip; wherein, the second annealing treatment is carried out in an air cushion furnace, the temperature of the second annealing treatment is ≥350°C, the time of the second annealing treatment is 5s to 300s, and the tension of the rubber roller in the air cushion furnace is ≥5MPa.

2. The preparation method according to claim 1, characterized in that: The temperature of the second annealing treatment is 350-550° C.; and / or, the time of the second annealing treatment is 10s-100s; and / or, the tension of the rubber roller in the air cushion furnace is 10-60MPa.

3. The preparation method according to claim 1 or 2, characterized in that: The rolling processing rate of each pass in the hot rolling treatment is 10% to 60%, preferably 20% to 40%; and / or the total processing rate of the hot rolling treatment is ≥80%, preferably 98.0% to 98.5%; and / or the temperature at the end of the hot rolling treatment is ≥280°C, preferably 300°C to 330°C; and / or the thickness of the hot-rolled plate obtained by the hot rolling treatment is 5.0 to 8.0 mm, preferably 5.0 to 7.5 mm.

4. The preparation method according to any one of claims 1 to 3, characterized in that The rolling processing rate of each pass in the first cold rolling treatment is 20% to 50%, preferably 20% to 40%; and / or the total processing rate of the first cold rolling treatment is ≥30%, preferably 58.3% to 73.3%; and / or the thickness of the first cold rolled plate obtained by the first cold rolling treatment is 1.5 to 4.0 mm, preferably 2.0 to 3.0 mm.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The rolling processing rate of each pass in the second cold rolling treatment is 10% to 40%, preferably 20% to 33%; and / or the total processing rate of the second cold rolling treatment is ≥50%, preferably 75% to 86.7%; and / or the thickness of the second cold rolled sheet obtained by the second cold rolling treatment is 0.1 to 1.0 mm, preferably 0.4 to 0.5 mm.

6. The preparation method according to any one of claims 1 to 5, characterized in that The average roughness of the roller in the first cold rolling process is 0.20 to 0.46 μm, preferably 0.30 to 0.35 μm; and / or the average roughness of the roller in the second cold rolling process is 0.10 to 0.20 μm, preferably 0.10 to 0.15 μm.

7. The preparation method according to any one of claims 1 to 6, characterized in that The temperature of the first annealing treatment is ≥300°C, preferably 350-500°C; and / or the holding time of the first annealing treatment is 1-10h, preferably 1-5h; and / or the temperature of the homogenization heat treatment is 600-610°C; and / or the holding time of the homogenization heat treatment is 8-20h.

8. The preparation method according to any one of claims 1 to 7, characterized in that The aluminum alloy ingot is selected from any one or more of 8006 aluminum alloy ingot, 8007 aluminum alloy ingot, 8008 aluminum alloy ingot, 8011 aluminum alloy ingot, 8021 aluminum alloy ingot, 8014 aluminum alloy ingot, 8050 aluminum alloy ingot, 8211 aluminum alloy ingot, 8023 aluminum alloy ingot and 8026 aluminum alloy ingot.

9. An aluminum alloy plate and strip, characterized in that: The aluminum alloy sheet and strip is prepared by the preparation method described in any one of claims 1 to 8.

10. The aluminum alloy sheet and strip according to claim 9, characterized in that: Measured by volume fraction, the proportion of Cube texture in the aluminum alloy sheet and strip is ≤10%, the proportion of Goss texture is ≤10%, the proportion of R texture is ≤20%, and the proportion of S texture is ≤15%; and / or the surface roughness of the aluminum alloy sheet and strip is 0.16-0.19μm; and / or the average grain size in the aluminum alloy sheet and strip is 6μm-14μm; and / or the tensile strength of the aluminum alloy sheet and strip is ≥105MPa, the yield strength is ≥45MPa, and the elongation is ≥37%.

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