Method for preparing 8011 aluminum alloy container foil

Abstract

The invention belongs to the technical field of 8011 aluminum alloy processing, and relates to a method for preparing 8011 aluminum alloy container foil, which comprises the following steps: S1, refining raw materials in a furnace to prepare an aluminum melt; s2, the aluminum melt is subjected to online refining, and refined aluminum melt is obtained; s3, the precision aluminum melt is subjected to cast rolling, and a cast rolling blank with the thickness being 6.5-7 mm is obtained; s4, the cast-rolled blank is subjected to cold rolling and edge cutting, and then a foil rolled blank with the thickness being 0.24-0.28 is obtained; s5, carrying out foil rolling on the foil rolling blank to obtain a 0.08-0.15 mm foil rolling aluminum foil; and S6, the foil-rolled aluminum foil is subjected to low-temperature annealing, and the target container aluminum foil is obtained after low-temperature annealing. According to the aluminum alloy container foil blank prepared through the method, the tensile strength is stabilized to be 105-120 MPa, the ductility is 18% or above, the cupping value is 7 or above, and the use requirements for high strength and high ductility of the aluminum alloy container foil can be met.

Description

Technical Field

[0001] The present invention belongs to the technical field of 8011 aluminum alloy processing, and relates to a method for preparing 8011 aluminum alloy container foil. Background Art

[0002] Due to its good ductility and corrosion resistance, 8011 aluminum alloy is widely used in food and drug packaging container foils. Because the content of alloying elements in 8011 is low and the performance is relatively soft; the traditional process uses a single annealing process to improve the performance, but it fails to solve the problems such as insufficient elongation after cold rolling, low yield rate, and poor surface quality. Moreover, the specifications of 8011 alloy container foils on the market are currently complex, resulting in low production efficiency. Therefore, it is necessary to develop an efficient preparation method through composition optimization and multi-stage collaborative processing. Summary of the Invention

[0003] The purpose of the present invention is to solve the above problems and provide a method for preparing 8011 aluminum alloy container foil.

[0004] To achieve the above purpose, the present invention provides a method for preparing 8011 aluminum alloy container foil. S1. Prepare an aluminum melt by in-furnace refining of raw materials;

[0005] S2. Carry out on-line refining on the aluminum melt to obtain a refined aluminum melt;

[0006] S3. Carry out casting and rolling on the precision aluminum melt to obtain a cast-rolled blank with a thickness of 6.5 - 7 mm;

[0007] S4. Carry out cold rolling and trimming on the cast-rolled blank, and then transfer it to obtain a foil-rolled blank with a thickness of 0.24 - 0.28;

[0008] S5. Carry out foil rolling on the foil-rolled blank to obtain a foil-rolled aluminum foil with a thickness of 0.08 - 0.10 mm;

[0009] S6. Carry out low-temperature annealing on the foil-rolled aluminum foil, and obtain the target container aluminum foil after low-temperature annealing.

[0010] Further, in S1, the raw material formula components are in mass percentages as follows: Si: 0.52 - 0.60%, Fe: 0.65 - 0.72%, Cu ≤ 0.05%, Mn ≤ 0.01%, Mg ≤ 0.01%, Zn ≤ 0.01%, Ti 0.02 - 0.04%, and the balance is Al.

[0011] Further, the on-line refining of the aluminum melt in step S2 includes: by using on-line addition of the grain refiner Al-Ti-B wire to ensure that the increase in titanium content is ≥ 0.012%, continuously charging pure argon with a purity of greater than or equal to 99.999% on-line for degassing, and carrying out off-line on-line refining through double filtration and using a filter plate with a mesh size of more than 40 and a thickness of 50 mm.

[0012] Further, in S3, the tundish temperature of the continuous casting and rolling is 680 - 700 °C, and the speed of the continuous casting and rolling is 900 - 1000 mm / min.

[0013] Further, in S4, the continuously cast and rolled blank is rolled through 5 passes to a foil rolling blank with a thickness of 0.25 - 0.30 mm. Among them, the passes of the cold rolling are respectively rolled to a thickness of 6.5 - 7.0 mm, 3.5 - 3.7 mm, 1.9 - 2.0 mm, 0.95 - 1.0 mm, 0.56 - 0.5 mm, followed by rewinding and trimming, and then rolled to a foil rolling aluminum blank with a thickness of 0.24 - 0.28 mm.

[0014] Further, in S5, the foil rolling blank is successively rolled to a foil rolling aluminum foil with a thickness of 0.24 - 0.28 mm, 0.17 - 0.2 mm, 0.12 - 0.15 mm, and 0.08 - 0.010 mm.

[0015] The method for preparing 8011 aluminum alloy container foil of the present invention has the following beneficial effects:

[0016] The tensile strength of the aluminum alloy container foil blank prepared by the method for preparing 8011 aluminum alloy container foil of the present invention is stably maintained at 105 - 120 MPa, the elongation rate is above 18%, and the Erichsen value is above 7, which can meet the requirements for high strength and high elongation rate of aluminum alloy container foil. Detailed Embodiments

[0017] The present invention provides a method for preparing 8011 aluminum alloy container foil. In S1, the raw materials are refined in a furnace to prepare an aluminum melt; in S2, the aluminum melt is refined online to obtain a refined aluminum melt; in S3, the refined aluminum melt is continuously cast and rolled to obtain a continuously cast and rolled blank with a thickness of 6.5 - 7 mm; in S4, the continuously cast and rolled blank is cold rolled and trimmed to obtain a foil rolling blank with a thickness of 0.24 - 0.28; in S5, the foil rolling blank is foil rolled to obtain a 0.08 - 0.10 mm foil rolling aluminum foil; in S6, the foil rolling aluminum foil is subjected to low - temperature annealing, and the target container aluminum foil is obtained after low - temperature annealing.

[0018] Among them, in S1, the raw material formula components are in mass percentages as follows: Si: 0.52 - 0.60% (improving fluidity and inhibiting the brittle phase of FeAl3), Fe: 0.65 - 0.72% (refining grains and enhancing strength), Cu ≤ 0.05% (solution strengthening), Mn ≤ 0.01% (reducing Fe segregation), Mg ≤ 0.01%, Zn ≤ 0.01%, Ti 0.02 - 0.04%, and the balance is Al, with a single impurity ≤ 0.01%. In step S2, the online refining of the aluminum melt includes: by using an online addition of a grain refiner, aluminum-titanium-boron wire, ensuring that the increase in titanium content is ≥ 0.012%, continuously and online filling with pure argon gas of not less than 99.999% for degassing, and through double filtration, using a filter plate with more than 40 meshes and a thickness of 50 mm for online refining outside the furnace. In S3, the front box temperature of the continuous casting and rolling is 680 - 700 °C, and the speed of the continuous casting and rolling is 900 - 1000 mm / min. In S4, the continuous casting and rolling billet is rolled into a foil rolling billet with a thickness of 0.25 - 0.30 mm through a total of 5 passes. Among them, the cold rolling passes are respectively rolled to a thickness of 6.5 - 7.0 mm, 3.5 - 3.7 mm, 1.9 - 2.0 mm, 0.95 - 1.0 mm, 0.56 - 0.5 mm, followed by rewinding and edge trimming, and then rolled into a foil rolling aluminum billet with a thickness of 0.24 - 0.28 mm. In S5, the foil rolling billet is successively rolled into foil rolling aluminum foils with thicknesses of 0.24 - 0.28 mm, 0.17 - 0.2 mm, 0.12 - 0.15 mm, and 0.08 - 0.010 mm.

[0019] The method for preparing 8011 aluminum alloy container foil of the present invention has good performance in terms of tensile strength and elongation rate of the aluminum alloy container foil obtained according to the above method. The following will detail the method for preparing 8011 aluminum alloy container foil of the present invention in specific embodiments:

[0020] In S1, according to the components of the above raw material formula, the prepared aluminum liquid and pure aluminum ingots are loaded into a melting furnace, and the solid cold charge is not less than 40% per furnace to achieve batching. Among them, the Si, Fe, and Cu elements are controlled in the form of impurity elements, and the Ti element is added online outside the furnace in the form of an Al - Ti - B master alloy wire.

[0021] During melting, degassing and slag removal are achieved by injecting refining agents into the furnace and filling pure argon gas to realize in-furnace refining. The in-furnace refining temperature is 730 - 750 °C. The refining agent is a combination of granular refining agent and liquid refining agent. The injection amount of the granular refining agent is 1 ± 0.2 Kg / t.Al, the in-furnace refining time is 20 - 25 minutes, the injection amount of the liquid refining agent is 0.1 ± 0.01 Kg / t.Al, and the in-furnace refining time is 18 - 20 minutes. The holding furnace adopts liquid crystal grains, with an injection amount of 1.0 ± 0.1 Kg / t.Al, the in-furnace refining frequency is 4 - 4.5 h / time, and slag skimming is carried out after each in-furnace refining.

[0022] In S2, during melting, the hydrogen content ≤ 0.12 ml / 100gAl. The addition speed of Al-Ti5-B1 wire is 80 - 110 m / min, the flow rate of pure argon gas is 6 - 12 L / min. Double filtration is achieved by using a tubular filtration and a plate filtration system, with the filtration mesh numbers being 50 mesh and 60 mesh respectively, and the on-line hydrogen content ≤ 0.12 mL / 100gAl.

[0023] In S3, the ears during continuous casting and rolling are chamfered ears, the continuous casting and rolling speed is 920 - 950 mm / min, the length of the continuous casting and rolling zone is (40 - 45) ± 4 mm, the temperature of the forehearth is 690 ± 2 °C in summer and 692 ± 2 °C in winter, and the cooling water temperature ≤ 45 °C; the flatness difference of the obtained continuous casting and rolling plate ≤ 0.02 mm, the edge difference ≤ 0.02 mm, and the camber is 0 - 0.04 mm.

[0024] In S4, the blank thickness is gradually rolled to: 6.5 - 7.0 mm, 3.5 - 3.7 mm, 1.9 - 2.0 m, 0.95 - 1.0 mm, 0.56 - 0.5 mm, re-winding and trimming, 0.24 - 0.28 mm. The distillation range of the rolling oil is 230 - 275 °C, the acid value is 0.3 - 0.6 mgKOH / g, the saponification value is 5 - 9 mg KOH / g , and the viscosity is 2.3 - 2.66 cst. The roughness of the blooming roll is 0.65 - 0.70 μm, and the roughness of the finished roll is 0.38 - 0.40 μm. During blooming rolling, the work roll must be replaced, and each roll in the guide path must be cleaned; there are no allowed surface defects such as continuous or intermittent scratches, gouges, imprints, etc. with a feel on the surface of the aluminum coil during blooming, and there are no allowed bright streaks, bright bands, or color differences; the surface blowing must be clean, and there is no allowed residual oil stain. During the first rolling pass, the processing rate must be guaranteed according to the process to ensure that the central layer structure of the continuous casting and rolling plate is rolled and broken to obtain a uniform internal structure.

[0025] In S5, the cold rolling reduction passes are: 0.24 - 0.28 mm, 0.17 - 0.2 mm, 0.12 - 0.15 mm, 0.08 - 0.010 mm. The distillation range of the rolling oil is 230 - 275 °C, the acid value is 0.3 - 0.7 mgKOH / g, the saponification value is 6 - 10mg KOH / g , with a viscosity of 2.2 - 2.45 cst. The hardness of the work roll is 100 - 102 HSD, the roughness of the backup roll is 0.6 - 0.7 μm, and the roughness of the work roll is 0.27 - 0.33 μm. The camber is 0.05 mm, and the dimensional deviation is ±1%. The thickness of the rolled foil is monitored in real time through an on-line thickness detection system, and the thickness deviation is automatically corrected and controlled to keep the aluminum foil thickness within the range of ±3%. During rolling, all guide rolls in the guide path must be wiped clean, and each guide roll is wiped with alcohol or rolling oil; ensure that there are no imprints, sticking aluminum, abrasions, or scratches on the surface of the aluminum coil. Those with oil stains on the surface shall not be sent to the annealing process. When rewinding and trimming the edges, a circular knife is used for trimming, and during slitting, edge defects such as oil, aluminum powder, and imprints are controlled.

[0026] In S6, the annealing process is to heat up to 330 °C in 1.5 hours, turn on the negative pressure blower to remove oil and keep warm for 4 hours, and then keep warm for 8 hours after turning off the blower. The temperature of the transfer material is 280 - 290 °C, and then it is cooled to 310 °C in 0.5 hours and taken out of the furnace after keeping warm for 8 hours. According to this method, it can play the role of eliminating stress and stabilizing the structure. At the same time, compared with the existing technology where annealing takes 30 - 39 hours, this method only requires 24 - 26 hours.

[0027] The experimental data for preparing 8011 aluminum alloy container foil of the present invention are as follows:

[0028] Using the blank preparation method described in this application, the aluminum alloys in the above embodiments are respectively made into container foil blanks with a thickness of 0.08 - 0.15 mm, and their mechanical properties are detected. The tensile strength, elongation, and Erichsen value of each alloy in the embodiment are measured, and the results are shown in the following table.

[0029] Example 1

[0030] Measured thickness / mm Tensile strength / MPa Elongation / % Cup drawing value / mm 0.085 116.5 20.8 7.1

[0031] Example 2

[0032] Measured thickness / mm Tensile strength / MPa Elongation / % Cup drawing value / mm 0.0914 121.6 20.2 7.3

[0033] Example 3

[0034] Measured thickness / mm Tensile strength / MPa Elongation / % Cup drawing value / mm 0.1000 115.3 19.4 7.6

[0035] Example 4

[0036] Measured thickness / mm Tensile strength / MPa Elongation / % Cup drawing value / mm 0.1101 119.4 22.1 7.5

[0037] Example 5

[0038] Measured thickness / mm Tensile strength / MPa Elongation / % Cup drawing value / mm 0.119 120.6 21.6 7.1

[0039] Example 6

[0040] Measured thickness / mm Tensile strength / MPa Elongation / % Cup drawing value / mm 0.1308 116.5 22.9 7.7

[0041] Example 7

[0042] Measured thickness / mm Tensile strength / MPa Elongation / % Cup drawing value / mm 0.1386 113.7 23.1 7.4

[0043] Example 8

[0044] Measured thickness / mm Tensile strength / MPa Elongation / % Cup drawing value / mm 0.150 116.9 24.9 7.5

[0045] The method for preparing 8011 aluminum alloy container foil of the present invention has the following advantages:

[0046] 1. The alloy composition is optimized. The ratios of Fe, Mn, Cu, and Si in the aluminum alloy are designed to improve the strength of the aluminum alloy, thereby fundamentally enhancing the strength of the container foil blank.

[0047] 2. The homogenization annealing is strictly controlled. The homogenization annealing process is reasonably designed to reduce the phenomenon of coarse grain appearance during homogenization annealing. By optimizing the process, the annealing duration is reduced, and energy consumption is saved.

[0048] 3. The reduction passes of cold rolling are reasonably set, and the process parameters of rolling oil and the roughness of rolling rolls are controlled to improve the sheet shape and surface quality.

[0049] The present invention suppresses brittle phases through Fe / Si ratio control, combines gradient annealing and asynchronous rolling, breaks through the contradiction between strength and formability of traditional processes, and has significant industrial application value. The tensile strength of the aluminum alloy container foil blank prepared by using the method for preparing 8011 aluminum alloy container foil and its blank of the present invention is stably within 105 - 120 MPa, the elongation is above 18%, and the Erichsen value is above 7, which can meet the usage requirements for high strength and high elongation of aluminum alloy container foil.

[0050] The above is only one embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing 8011 aluminum alloy container foil, characterized in that: S1. Prepare an aluminum melt by in-furnace refining of raw materials; S2. Conduct on-line refining on the aluminum melt to obtain a refined aluminum melt; S3. Cast-roll the refined aluminum melt to obtain a cast-rolled blank with a thickness of 6.5 - 7 mm; S4. After cold rolling and trimming the cast-rolled blank, transfer it to obtain a foil rolling blank with a thickness of 0.24 - 0.28 mm; S5. Foil-roll the foil rolling blank to obtain a foil-rolled aluminum foil with a thickness of 0.08 - 0.10 mm; S6. Conduct low-temperature annealing on the foil-rolled aluminum foil, and obtain the target container aluminum foil after low-temperature annealing.

2. The method for preparing 8011 aluminum alloy container foil according to claim 1, wherein In S1, the component formulation of the raw materials is by mass percentage: Si: 0.52 - 0.60%, Fe: 0.65 - 0.72%, Cu ≤ 0.05%, Mn ≤ 0.01%, Mg ≤ 0.01%, Zn ≤ 0.01%, Ti 0.02 - 0.04%, and the balance is Al.

3. The method for preparing 8011 aluminum alloy container foil according to claim 2, wherein In step S2, the on-line refining of the aluminum melt includes: by on-line adding a grain refiner Al-Ti-B wire to ensure that the increase in titanium content ≥ 0.012%, continuously on-line filling with pure argon gas of ≥ 99.999% for degassing, and through double filtration, using a filter plate with more than 40 meshes and a thickness of 50 mm for out-of-furnace on-line refining.

4. The method for preparing 8011 aluminum alloy container foil according to claim 3, characterized in that, In S3, the front box temperature of the cast-rolling is 680 - 700 °C, and the cast-rolling speed is 900 - 1000 mm / min.

5. The method for preparing 8011 aluminum alloy container foil according to claim 4, characterized in that, In S4, the cast-rolled blank is rolled through a total of 5 passes to a foil rolling blank with a thickness of 0.25 - 0.30 mm. Among them, the passes of the cold rolling are respectively rolled to a thickness of 6.5 - 7.0 mm, 3.5 - 3.7 mm, 1.9 - 2.0 mm, 0.95 - 1.0 mm, 0.56 - 0.5 mm, re-wound and trimmed, and then rolled to a foil rolling aluminum blank with a thickness of 0.24 - 0.28 mm.

6. The method for preparing 8011 aluminum alloy container foil according to claim 5, characterized in that, In S5, the foil rolling blank is successively rolled to a foil-rolled aluminum foil with a thickness of 0.24 - 0.28 mm, 0.17 - 0.2 mm, 0.12 - 0.15 mm, 0.08 - 0.010 mm.