6-series aluminum alloy plate for oxygen storage tank and production method of 6-series aluminum alloy plate

Abstract

The invention belongs to the technical field of aluminum alloy machining technologies, and particularly discloses a 6-series aluminum alloy plate for an oxygen storage tank and a production method thereof.The production method includes the steps that burdening, fusion casting, cast ingot homogenization, rolling, annealing and uncoiling sizing are conducted, an aluminum alloy plate is obtained, in the rolling process, a heat preservation cast ingot is subjected to rough rolling and then finish rolling, and the aluminum alloy plate is obtained. The machining rates of the last but one pass of rolling, the third pass of rolling and the fourth pass of rolling in the finish rolling are all 45%-55%, the machining rate of the last pass of rolling is 30%-40%, the finish rolling temperature of the last pass of rolling is 260-290 DEG C, and the coiled material is obtained after rolling. The obtained 6-series aluminum alloy plate for the oxygen storage tank is free of deep drawing cracking, fine in grain and high in heat treatment strength, and the oxygen storage tank obtained through the aluminum alloy plate is free of cracking, free of orange peel on the surface and good in use effect.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy processing technology, and specifically discloses a 6-series aluminum alloy sheet for oxygen storage tanks and its production method. Background Technology

[0002] Aluminum alloys, due to their low density, high specific strength, ease of processing and forming, good corrosion resistance, and weldability, have become the preferred material for lightweighting in the manufacturing of oxygen storage equipment. With continuous upgrades in product design, the processing requirements for aluminum alloy sheets are becoming increasingly stringent. Deep drawing is a common processing method that can shape aluminum alloy sheets into complex-shaped oxygen storage container components, meeting diverse equipment structural needs and thereby improving the overall performance and safety of oxygen storage equipment.

[0003] 6-series aluminum alloys are widely used in the manufacture of oxygen storage equipment due to their moderate strength, good plasticity and weldability, excellent corrosion resistance, and lack of stress corrosion cracking tendency. Furthermore, 6-series aluminum alloys are heat-treatable, further expanding their application range. The common production process for 6061-O aluminum alloy sheets is: casting (single-stage filtration) - milling - heating - hot rolling - box annealing - cross shearing - packaging. However, due to the high temperature during rolling, the distortion energy storage is relatively reduced, resulting in insufficient energy storage during subsequent recrystallization annealing and a decrease in the number of grain nuclei. This leads to low deformation energy storage during rolling, making it prone to incomplete annealing or coarse grains during annealing.

[0004] Existing aluminum alloy sheets have the following drawbacks: they are prone to cracking during deep drawing, and after annealing, the grains are coarse and the surface exhibits an orange peel effect. These defects not only reduce the fatigue life of oxygen storage tanks but also lead to insufficient material strength after heat treatment, affecting the safety of the oxygen storage tanks. Therefore, researching and designing a new type of 6-series aluminum alloy sheet for oxygen storage tanks and its production method to overcome the shortcomings of existing technologies is of great significance. Summary of the Invention

[0005] To address the problems of deep drawing cracking, coarse grains, and low heat treatment strength affecting the safety of hydrogen storage tanks in existing 6-series aluminum alloy sheets for oxygen storage tanks, this invention proposes a 6-series aluminum alloy sheet for oxygen storage tanks and its production method.

[0006] The first aspect of this invention provides a 6-series aluminum alloy sheet for oxygen storage tanks, wherein the components and their weight percentages in the aluminum alloy sheet are as follows:

[0007] The Si content is 0.60%~0.80%;

[0008] The Fe content is 0.30%~0.60%;

[0009] The Cu content is 0.20%~0.40%;

[0010] Mn≤0.15%;

[0011] The Mg content is 0.90%~1.10%;

[0012] The Cr content is 0.15%~0.25%;

[0013] Zn content ≤ 0.10%;

[0014] The Ti content is 0.015%~0.025%;

[0015] The content of a single impurity is ≤0.03%;

[0016] Total impurity content ≤ 0.10%;

[0017] The balance is Al.

[0018] According to some embodiments of this application, a 6-series aluminum alloy sheet for an oxygen storage tank has a thickness of 4.1 mm to 4.8 mm.

[0019] A second aspect of this invention provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks, comprising the following steps:

[0020] S1. Batching the ingredients to obtain aluminum alloy raw materials;

[0021] S2. Melting and casting: Melting and casting the prepared aluminum alloy raw materials to obtain ingots;

[0022] S3. Ingot homogenization: The ingot is homogenized and then cooled and kept warm to obtain a heat-insulated ingot;

[0023] S4. Rolling: The heat-insulating ingot is rough rolled and then finish rolled. The processing rate of the penultimate, third and fourth finish rolling passes is 45%~55%, the processing rate of the last rolling pass is 30%~40%, and the final rolling temperature of the last rolling pass is 260℃~290℃. After rolling, a coil is obtained.

[0024] S5. Annealing: After cooling the roll material, anneal it and then cool it to room temperature.

[0025] S6. Uncoiling and Length Setting: The annealed coil is uncoiled and length set to obtain aluminum alloy sheet.

[0026] According to some embodiments of this application, a method for producing 6-series aluminum alloy plates for oxygen storage tanks is described. In step S2, the casting process involves refining and covering with flux. The casting process includes melting, refining, slag removal, degassing, and casting. The casting process uses a two-stage filtration system and Al-Ti-B wires to refine the grains. The two-stage filtration system includes one of the following: plate-type CFF dual filtration, a combination of plate-type CFF filtration and deep bed filtration, or a combination of plate-type CFF filtration and tubular filtration.

[0027] According to some embodiments of this application, a method for producing 6-series aluminum alloy plates for oxygen storage tanks, in step S3, before the ingot is homogenized, the ingot is cooled and the head and tail are cut off, and the surface solidified layer of the ingot is milled off.

[0028] According to some embodiments of this application, a method for producing 6-series aluminum alloy plates for oxygen storage tanks, in step S3, the metal temperature for homogenization treatment is 540℃~570℃, the holding time is 4h~10h, and after homogenization, the temperature is lowered to 470℃~510℃, and the holding time is 2h~20h.

[0029] According to some embodiments of this application, a method for producing 6-series aluminum alloy sheet for oxygen storage tanks, in step S4, the initial temperature of rough rolling is 470℃~510℃, the number of rough rolling passes is 16~18, and the thickness of the intermediate billet obtained after rough rolling is 55mm~65mm.

[0030] According to some embodiments of this application, a method for producing 6-series aluminum alloy sheet for oxygen storage tanks, in step S4, the finishing rolling passes are 4 passes, and the second to last, third and fourth finishing rolling passes are cooled by emulsion spraying.

[0031] According to some embodiments of this application, a method for producing 6-series aluminum alloy sheet for oxygen storage tanks, in step S5, the annealing temperature is 330℃~350℃, the holding time is 1h~3h, and the annealing is performed by rapid heating at a rate of 90~110℃ / h.

[0032] The third aspect of the present invention provides a 6-series aluminum alloy sheet for oxygen storage tanks produced by the above-described production method.

[0033] This invention proposes a 6-series aluminum alloy sheet for oxygen storage tanks and its production method. By optimizing the alloy element ratio, the material exhibits good plasticity after annealing to the O state, which is beneficial for deep drawing of the oxygen storage tank liner. Simultaneously, it ensures that the oxygen storage tank liner has high mechanical properties after solution quenching and artificial aging. Homogenization treatment and heat preservation eliminate grain segregation, preventing uneven recrystallization caused by grain segregation. Controlling the pass rate and final rolling temperature of the finishing roll improves the deformation energy storage of the coil. Rapid heating during annealing increases the recrystallization nucleation rate, resulting in smaller recrystallized grains and preventing orange peel texture during later deep drawing, which can lead to material cracking. High-temperature short-time annealing completes recrystallization while preventing grain growth, thus preventing deep drawing cracking. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the production process of 6-series aluminum alloy sheet for oxygen storage tanks according to the present invention. Detailed Implementation

[0035] The endpoints and any values ​​of the ranges 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 endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0036] The first aspect of this invention provides a 6-series aluminum alloy sheet for oxygen storage tanks, wherein the components and their weight percentages in the aluminum alloy sheet are as follows:

[0037] The Si content is 0.60%~0.80%;

[0038] The Fe content is 0.30%~0.60%;

[0039] The Cu content is 0.20%~0.40%;

[0040] Mn≤0.15%;

[0041] The Mg content is 0.90%~1.10%;

[0042] The Cr content is 0.15%~0.25%;

[0043] Zn content ≤ 0.10%;

[0044] The Ti content is 0.015%~0.025%;

[0045] The content of a single impurity is ≤0.03%;

[0046] Total impurity content ≤ 0.10%;

[0047] The balance is Al.

[0048] In this invention, the Fe content is controlled at 0.30%~0.60%, which is beneficial for grain refinement. While satisfying the Mg2Si chemical composition ratio, adding a little excess Si, with Si controlled at the upper limit, can eliminate the acicular FeAl3 phase. The FeAl3 phase easily leads to cracking during subsequent deep drawing. Eliminating the FeAl3 phase can improve the mechanical properties of the material after heat treatment. Therefore, the Si content is controlled at 0.60%~0.80%, and the Mg content is 0.90%~1.10%. The copper content is controlled at 0.2%~0.4%, which is beneficial for increasing the strength of the material after heat treatment. Cr has the effect of refining grains, but Cr will reduce the plasticity of the material. In this invention, the Cr content is controlled at 0.15%~0.25%.

[0049] A second aspect of this invention provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks, comprising the following steps:

[0050] S1. Batching the ingredients to obtain aluminum alloy raw materials.

[0051] S2. Melting and casting: Melting and casting the prepared aluminum alloy raw materials to obtain ingots.

[0052] According to the present invention, in step S2, more preferably, the casting process includes sequentially feeding the aluminum alloy raw material into a melting furnace for melting, while simultaneously using flux for refining and covering. After the aluminum alloy raw material in the furnace is completely melted, stirring begins, followed by refining, slag removal, and other production operations to obtain a melt. Ar gas is then used to carry hydrogen and fine impurities in the melt to the surface of the melt, reducing the gas and slag content. The melt undergoes online degassing and dual-stage filtration to obtain the ingot. The dual-stage filtration includes one of plate-type CFF dual filtration, a combination of plate-type CFF filtration and deep-bed filtration, or a combination of plate-type CFF filtration and tubular filtration. Dual-stage filtration can reduce the slag content of the melt and ensure melt purity. Furthermore, the present invention can also use Al-5Ti-B for online refining treatment to ensure fine ingot grains.

[0053] S3. Ingot homogenization: The ingot is homogenized and then cooled and kept warm to obtain a heat-insulated ingot.

[0054] According to the present invention, in step S3, more preferably, before homogenization of the ingot, the ingot is cooled and the head and tail are cut off, and the surface solidified layer of the ingot is milled off. The metal temperature for homogenization treatment is 540℃~570℃, and the holding time is 4h~10h to eliminate grain segregation. After homogenization, the temperature is lowered to 470℃~510℃, and the holding time is 2h~20h.

[0055] S4. Rolling: The heat-insulating ingot is rough rolled and then finish rolled. The processing rate of the penultimate, third and fourth finishing rolling passes is 45%~55%, the processing rate of the last rolling pass is 30%~40%, and the final rolling temperature of the last rolling pass is 260℃~290℃. After rolling, a coil is obtained.

[0056] According to the present invention, in step S4, more preferably, the initial temperature of the rough rolling is 470℃~510℃, the number of rough rolling passes is 16~18, and the thickness of the intermediate billet obtained after rough rolling is 55mm~65mm. The number of finishing rolling passes is 4, and the penultimate, third, and fourth finishing rolling passes are cooled by emulsion spraying to control the temperature at the end of each passing pass, avoiding the inability to control the final rolling temperature within the required range in the last passing pass. The final rolling temperature of the last passing pass is 260℃~290℃. Using low-temperature rolling allows the material to retain more deformation energy, resulting in more crystal nuclei recrystallized during annealing of the coil, and relatively smaller grain size after annealing. This improves the mechanical properties of the finished sheet through fine-grain strengthening.

[0057] S5. Annealing: After cooling the roll material, anneal it and then cool it to room temperature.

[0058] According to the present invention, in step S5, more preferably, the annealing metal temperature is 330℃~350℃, the holding time is 1h~3h, and the annealing is carried out by rapid heating at a rate of 90~110℃ / h. By rapidly heating, the nucleation rate during recrystallization of the roll material is increased. Controlling the holding time can prevent the recrystallized grains from growing to an excessively large size during annealing. Fine grains in the finished sheet will improve the strength and elongation of the finished sheet and avoid cracking and orange peel during deep drawing of the sheet later.

[0059] S6. Uncoiling and Length Setting: The annealed coil is uncoiled and length set to obtain aluminum alloy sheet.

[0060] A third aspect of the present invention provides a 6-series aluminum alloy sheet for an oxygen storage tank produced by the above-described production method.

[0061] The finished state of the 6-series aluminum alloy sheet used for the oxygen storage tank is O-state, with a thickness of 4.1mm~4.8mm. After rolling, the mechanical properties of the material are reduced to a fully soft state through coil annealing. During mechanical testing, the finished sheet is strengthened to T62 state through heat treatment such as laboratory solution quenching and artificial aging, proving that the high strength state achieved by the sheet after the later heat treatment meets the technical requirements of the oxygen storage cylinder.

[0062] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0063] Example 1: This example provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks, including the following steps:

[0064] Ingredients: Aluminum alloy raw materials are prepared according to the following weight ratios: Si content 0.658%; Fe content 0.544%; Cu content 0.267%; Mn content 0.098%; Mg content 1.022%; Cr content 0.177%; Zn content 0.012%; Ti content 0.017%; individual impurity content ≤0.03%; total impurity content ≤0.10%; balance Al.

[0065] Melting and casting: The aluminum alloy raw materials are sequentially added to a melting furnace for melting, while flux is used for refining and covering. After the aluminum alloy raw materials in the furnace are completely melted, stirring is started, followed by refining, slag removal and other production operations to obtain a melt. Ar gas is then used to carry hydrogen and fine impurities in the melt to the surface of the melt, reducing the gas and slag content in the melt. After online degassing and double-stage filtration, the melt undergoes online refinement treatment with Al-5Ti-B to obtain the ingot.

[0066] Ingot homogenization: After cooling the ingot, the head and tail are cut off, and the surface solidified layer of the ingot is milled off on a milling machine. The ingot is then placed in a pusher furnace for homogenization treatment. The metal temperature for homogenization treatment is 550℃, and the holding time is 8 hours to eliminate grain segregation. After homogenization, the temperature is lowered to 500℃ and held for 4 hours. The ingot exiting the furnace at the holding temperature is 502℃.

[0067] Rolling: The heat-insulating ingot is subjected to 16 passes of rough rolling at an initial temperature of 502°C. The thickness of the intermediate billet obtained after rough rolling is 60 mm. Then, it is subjected to finish rolling. The processing rate of the penultimate, third, and fourth passes of finish rolling is 50%, and the processing rate of the last pass is 35%. The final rolling temperature of the last pass is 274°C. After rolling, a coil is obtained.

[0068] Annealing: After cooling, the coil is transferred to a cold rolling annealing furnace for annealing. The coil heating rate is 100℃ / h to improve the recrystallization nucleation rate of the material and refine the grains. The annealing metal temperature is 340℃, the holding time is 3h, and after the holding time is completed, it is naturally cooled to room temperature.

[0069] Uncoiling and length setting: The annealed coil is transferred to a cross-cutting shear for uncoiling and length setting to obtain aluminum alloy sheet.

[0070] Example 2: This example provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. It adopts the method for producing 6-series aluminum alloy sheet for oxygen storage tanks in Example 1. The difference from Example 1 is that the ingot homogenization and heat preservation ingot exit temperature is 509°C, the final rolling temperature of the last rolling pass is 273°C, the heating rate during annealing is 98°C / h, and the metal temperature during annealing is 339°C.

[0071] Example 3 provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. The method used in Example 1 differs from that in Example 1 in that the aluminum alloy raw materials are prepared according to the following weight ratios: Si content 0.653%; Fe content 0.526%; Cu content 0.274%; Mn content 0.099%; Mg content 0.998%; Cr content 0.188%; Zn content 0.010%; Ti content 0.017%; individual impurity content ≤0.03%; total impurity content ≤0.10%; balance Al. The ingot homogenization and holding temperature after casting is 497℃. The final rolling temperature of the last rolling pass is 272℃. The annealing heating rate is 102℃ / h, and the annealing metal temperature is 338℃.

[0072] Example 4 provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. The method used in Example 3 differs from that in Example 3 in that the aluminum alloy raw materials are prepared according to the following weight ratios: Si content 0.613%; Fe content 0.36%; Cu content 0.214%; Mn content 0.095%; Mg content 0.915%; Cr content 0.158%; Zn content 0.010%; Ti content 0.016%; individual impurity content ≤0.03%; total impurity content ≤0.10%; balance Al. The ingot homogenization and holding temperature after casting is 495℃, the final rolling temperature of the last rolling pass is 273℃, and the annealing temperature is 341℃.

[0073] Example 5 provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. The method used in Example 3 differs from that in Example 3 in that the aluminum alloy raw materials are prepared according to the following weight ratios: Si content 0.786%; Fe content 0.58%; Cu content 0.389%; Mn content 0.13%; Mg content 1.05%; Cr content 0.241%; Zn content 0.095%; Ti content 0.023%; individual impurity content ≤0.03%; total impurity content ≤0.10%; balance Al. After homogenization, the ingot is held at a furnace temperature of 498℃. The final rolling temperature in the last rolling pass is 275℃. The annealing heating rate is 99℃ / h, and the annealing metal temperature is 340℃.

[0074] Example 6: This example provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. It adopts the method for producing 6-series aluminum alloy sheet for oxygen storage tanks in Example 3. The difference from Example 3 is that the ingot is kept at a furnace temperature of 494°C after homogenization, the final rolling temperature of the last rolling pass is 263°C, the heating rate during annealing is 101°C / h, and the metal temperature during annealing is 341°C.

[0075] Example 7: This example provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. It adopts the method for producing 6-series aluminum alloy sheet for oxygen storage tanks in Example 3. The difference from Example 3 is that the ingot is kept at a furnace temperature of 496°C after homogenization, the final rolling temperature of the last rolling pass is 286°C, the heating rate during annealing is 100°C / h, and the metal temperature during annealing is 339°C.

[0076] Example 8: This example provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. It adopts the method for producing 6-series aluminum alloy sheet for oxygen storage tanks in Example 3. The difference from Example 3 is that the ingot homogenization temperature is 540°C, the ingot holding temperature after homogenization is 498°C, the final rolling temperature of the last rolling pass is 275°C, the heating rate during annealing is 98°C / h, and the metal temperature during annealing is 341°C.

[0077] Example 9: This example provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. It adopts the method for producing 6-series aluminum alloy sheet for oxygen storage tanks in Example 3. The difference from Example 3 is that the ingot homogenization temperature is 569°C, the ingot holding temperature after homogenization is 499°C, the final rolling temperature of the last rolling pass is 278°C, the final rolling temperature of the last rolling pass is 275°C, the heating rate during annealing is 98°C / h, and the metal temperature during annealing is 341°C.

[0078] Example 10: This example provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. It adopts the method for producing 6-series aluminum alloy sheet for oxygen storage tanks in Example 3. The difference from Example 3 is that the ingot is kept at a furnace temperature of 507°C after homogenization, the final rolling temperature of the last rolling pass is 277°C, the heating rate during coil annealing is 100°C / h, the metal temperature during annealing is 330°C, and the holding time is 3h.

[0079] Example 11: This example provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. It adopts the method for producing 6-series aluminum alloy sheet for oxygen storage tanks in Example 3. The difference from Example 3 is that the ingot is kept at a furnace temperature of 506°C after homogenization, the final rolling temperature of the last rolling pass is 275°C, the heating rate during coil annealing is 99°C / h, the metal temperature during annealing is 350°C, and the holding time is 3h.

[0080] Example 12: This example provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. It adopts the method for producing 6-series aluminum alloy sheet for oxygen storage tanks in Example 3. The difference from Example 3 is that the ingot is kept at a furnace temperature of 506°C after homogenization, the final rolling temperature of the last rolling pass is 275°C, the heating rate during coil annealing is 90°C / h, and the metal temperature during annealing is 340°C.

[0081] Example 13: This example provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. It adopts the method for producing 6-series aluminum alloy sheet for oxygen storage tanks in Example 3. The difference from Example 3 is that the ingot homogenization and heat preservation ingot exit temperature is 506°C, the final rolling temperature of the last rolling pass is 275°C, the heating rate during coil annealing is 110°C / h, and the metal temperature during annealing is 339°C.

[0082] Comparative Example 1 provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks, using the method described in Example 3. The difference is that the aluminum alloy raw materials in this comparative example are prepared according to the following weight ratios: Si content 0.496%; Fe content 0.491%; Cu content 0.241%; Mn content 0.097%; Mg content 1.15%; Cr content 0.268%; Zn content 0.02%; Ti content 0.019%; individual impurity content ≤0.03%; total impurity content ≤0.10%; balance Al. The ingot homogenization and holding temperature after casting is 498°C, the final rolling temperature of the last rolling pass is 275°C, the heating rate during coil annealing is 99°C / h, and the metal temperature during annealing is 339°C.

[0083] Comparative Example 2 provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. It adopts the method for producing 6-series aluminum alloy sheet for oxygen storage tanks in Example 3. The difference from Example 3 is that in this comparative example, the furnace exit temperature of the ingot after homogenization and heat preservation is 501°C, the final rolling temperature of the last rolling pass is 305°C, the heating rate during coil annealing is 99°C / h, and the metal temperature during annealing is 341°C.

[0084] Comparative Example 3 provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. It adopts the method for producing 6-series aluminum alloy sheet for oxygen storage tanks in Example 3. The difference from Example 3 is that the ingot is not homogenized in this comparative example. After the ingot is kept warm, the ingot exit temperature is 498°C. The final rolling temperature of the last rolling pass is 271°C. The heating rate during coil annealing is 100°C / h. The metal temperature during annealing is 340°C.

[0085] Comparative Example 4 provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. It adopts the production method of 6-series aluminum alloy sheet for oxygen storage tanks in Example 3. The difference from Example 3 is that in this comparative example, the ingot is kept at a furnace temperature of 504°C after homogenization, the final rolling temperature of the last rolling pass is 277°C, and the coil annealing is carried out according to the traditional annealing system with an annealing temperature of 360°C and a holding time of 3 hours. The heating rate during annealing is 98°C / h.

[0086] Comparative Example 5 provides a method for producing 6-series aluminum alloy sheet for oxygen storage tanks. It adopts the method for producing 6-series aluminum alloy sheet for oxygen storage tanks in Example 3. The difference from Example 3 is that in this comparative example, the ingot is kept warm after homogenization and the furnace exit temperature is 502°C. The final rolling temperature of the last rolling pass is 275°C. The heating rate during coil annealing is carried out at the conventional rate of 80°C / h. The metal temperature during annealing is 339°C.

[0087] The oxygen storage tanks prepared and processed in Examples 1-13 and Comparative Examples 1-5 were sampled and processed using 6-series aluminum alloy sheets. Tensile strength, yield strength, elongation, and grain size of the aluminum alloy sheets in the O and T62 states were tested according to relevant testing standards. The test results are shown in Table 1.

[0088] Table 1 Test Results

[0089]

[0090] As can be seen from the table above, the aluminum alloy sheet samples obtained using the method of this invention exhibit excellent O-state plasticity, making them suitable for deep drawing. The aluminum alloy sheet samples treated with T62 heat treatment show high mechanical properties. Grain size analysis of the samples reveals fine grains in the aluminum alloy sheets. Furthermore, the aluminum alloy sheets obtained using this method, when deep-drawn into cans, show no orange peel or cracking on the surface, indicating good performance.

[0091] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A 6-series aluminum alloy sheet for an oxygen storage tank, characterized by, The aluminum alloy plate comprises the following components and their weight percentages: Si content is 0.60%~0.80%; Fe content is 0.30%~0.60%; Cu content is 0.20%~0.40%; Mn≤0.15%; Mg content is 0.90%~1.10%; Cr content is 0.15%~0.25%; Zn content≤0.10%; Ti content is 0.015%~0.025%; Single impurity content≤0.03%; Total impurity content≤0.10%; Balance is Al.

2. The 6-series aluminum alloy sheet for an oxygen storage tank according to claim 1, characterized by, The thickness of the aluminum alloy plate is 4.1mm~4.8mm.

3. A method of producing a 6-series aluminum alloy sheet for an oxygen storage tank according to claim 1 or 2, characterized by, The method comprises the following steps: S1. batching, obtaining aluminum alloy raw materials; S2. melting and casting: melting and casting the prepared aluminum alloy raw materials to obtain ingots; S3. ingot homogenization: homogenizing the ingot and cooling and holding to obtain a holding ingot; S4. rolling: rough rolling and then finish rolling the holding ingot, the reduction rate of the penultimate pass, the third pass and the fourth pass of the finish rolling is 45%~55%, the reduction rate of the last pass is 30%~40%, the finish rolling temperature of the last pass is 260℃~290℃, and the rolled material is obtained after rolling; S5. annealing: cooling the rolled material and then annealing, and cooling to room temperature after annealing; S6. uncoiling and sizing: uncoiling and sizing the annealed rolled material to obtain an aluminum alloy plate.

4. The method of producing a 6-series aluminum alloy sheet for an oxygen storage tank according to claim 3, characterized by, In the step S2, the melting and casting adopts flux refining covering, the melting and casting comprises melting, refining, slagging, degassing and casting, double-stage filtration is used in the casting process, and Al-Ti-B wire is used to refine grains, the double-stage filtration comprises one of plate type CFF double filtration, plate type CFF filtration combined with deep bed filtration, or plate type CFF filtration combined with pipe type filtration.

5. The method of producing a 6-series aluminum alloy sheet for an oxygen storage tank according to claim 3, characterized by, In the step S3, the ingot is cooled after the ingot homogenization, the head and tail are cut off, and the surface layer condensate layer of the ingot is milled off.

6. The production method of a 6-series aluminum alloy sheet for an oxygen storage tank according to claim 3, characterized in that, In the step S3, the metal temperature of the homogenization treatment is 540℃~570℃, the holding time is 4h~10h, the temperature is lowered to 470℃~510℃ after the homogenization ends, and the holding time is 2h~20h.

7. The method of producing a 6-series aluminum alloy sheet for an oxygen storage tank according to claim 3, characterized in that, In the step S4, the initial temperature of the rough rolling is 470℃~510℃, the rough rolling passes are 16~18, and the thickness of the intermediate blank obtained after the rough rolling is 55mm~65mm.

8. The method of producing a 6-series aluminum alloy sheet for an oxygen storage tank according to claim 3, characterized by, In the step S4, the finish rolling passes are 4, and the emulsion is sprayed to cool down during the penultimate pass, the third pass and the fourth pass of the finish rolling.

9. The method of producing a 6-series aluminum alloy sheet for an oxygen storage tank according to claim 3, characterized in that, In the step S5, the metal temperature of the annealing is 330℃~350℃, the holding time is 1h~3h, the annealing is rapidly heated, and the heating speed is 90~110℃ / h.

10. The 6-series aluminum alloy plate for oxygen storage tank produced by the production method of any one of claims 3-9.

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