Method for eliminating stripes on surface of 3003 cathode foil

Abstract

The invention relates to the technical field of aluminum foil processing, in particular to a method for eliminating stripes on the surface of 3003 cathode foil, which comprises the following steps of: 1, adding a cold material into electrolytic aluminum water for smelting to obtain an aluminum alloy melt; 2, refining and slagging-off are conducted; step 3, turning down and refining in a holding furnace; step 4, filtering and degassing; 5, cast rolling is conducted; sixthly, primary cold rolling and edge cutting are conducted; seventhly, secondary cold rolling is conducted; step 8, annealing; and ninthly, the annealed blank is subjected to foil rolling and slitting in sequence, and a finished product with the thickness being 0.02-0.03 mm is obtained. According to the method, the components, the proportion, the production process and parameters of the aluminum alloy melt are regulated and controlled, and surface stripes of the aluminum alloy finished product are eliminated on the premise that the mechanical performance and the specific volume of the aluminum alloy finished product are not reduced.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum foil processing, and in particular to a method for eliminating surface stripes of a 3003 cathode foil. Background Art

[0002] Capacitors are commonly used electronic components in electronic devices for storing electric charge. They are quite common in electronic products such as flat-screen TVs, laptops, and digital cameras. Capacitors mainly include capacitor plates, dielectrics, shells, and lead wires. Among them, the main function of the capacitor plates is to form an electric field at both ends of the capacitor and store charged particles. The electrode foil is the key material for making capacitor plates. The commonly used materials for electrode foil are mainly silver, copper, and aluminum alloys. Silver electrode foil has good conductivity, chemical stability, and corrosion resistance, but the cost is high and it is not suitable for large-scale production; copper electrode foil has a lower cost, but due to the more active chemical properties of copper, the chemical stability is poor. The main function of the capacitor shell is to protect the internal components, and its quality has a great impact on the life of the capacitor product. At present, the commonly used capacitor shell materials are iron, plastic, aluminum alloy, etc. The iron shell has high mechanical properties and is not easy to deform and crack, but due to its high density, it is not easy to transport, and it is easy to rust and corrode, and has a short service life; the plastic shell is light and has good corrosion resistance and processability, but it has poor flame retardancy. When the capacitor is operated at high temperature for a long time, there are certain safety hazards. Aluminum alloy materials are inexpensive and durable, and have the advantages of light weight, corrosion resistance, machinability and good heat dissipation. They are widely used in the production of capacitor casings and capacitor electrode foils.

[0003] Aluminum alloy materials can be divided into 1000 series, 2000 series, 3000 series, 4000 series, 5000 series, 6000 series and 7000 series according to chemical composition and elements contained. The 3003 aluminum alloy in the 3000 series not only has the advantages of low density, soft material, easy processing and forming, corrosion resistance at high temperature, good heat transfer and electrical conductivity, but also has high post-corrosion strength. It is a common material for capacitor shells and capacitor electrode foils. In the casting and rolling production process of 3003 aluminum alloy, the surface of aluminum alloy products is prone to stripe defects. Light surface stripes will affect the appearance of aluminum alloy products, while heavy surface stripes will affect the mechanical properties of aluminum alloy products and cause defects such as punching cracks, resulting in the scrapping of aluminum alloy products. Summary of the invention

[0004] Aiming at the technical problem that in the existing casting and rolling production process of 3003 aluminum alloy, the surface of aluminum alloy products is very likely to produce stripe defects, the present invention provides a method for eliminating the surface stripes of 3003 cathode foil, by adjusting the composition and proportion of aluminum alloy melt, production process and parameters, the surface stripes of aluminum alloy products are eliminated without reducing the mechanical properties and specific volume of the aluminum alloy products.

[0005] The technical solution of the present invention is as follows: A method for eliminating stripes on the surface of 3003 cathode foil comprises the following steps: Step 1: adding the cold material into the electrolytic aluminum water for smelting to obtain an aluminum alloy melt, wherein the composition of the aluminum alloy melt is as follows by mass percentage: Si≤0.1%, Fe: 0.2%-0.5%, Cu: 0.10%-0.15%, Mn: 1.0%-1.5%, Mg≤0.05%, Zn≤0.05%, Ti: 0.01%-0.03%, and the balance is Al; Step 2: Preheated argon gas is introduced into the aluminum alloy melt from the bottom of the melting furnace to perform initial "Z"-shaped refining, and then the slag is removed to obtain a crude refined aluminum liquid; Step 3: pour the crude refined aluminum liquid into a holding furnace, and intermittently introduce preheated argon gas from above the bottom of the holding furnace into the crude refined aluminum liquid for "Z"-shaped refining to obtain refined aluminum liquid; Step 4: adding a grain refiner to the refined aluminum liquid for grain refinement, and then performing online degassing and filtration to obtain aluminum liquid with a first-grade grain size; Step 5: Casting and rolling, controlling the front box temperature to 680-700°C and the casting and rolling speed to 790-810 mm / min, to obtain a billet with a thickness of 6.5-8 mm; Step 6: cold rolling the blank for 4 passes, and then trimming the blank to obtain the primary cold rolled blank; Step 7: performing secondary cold rolling on the primary cold rolled billet to obtain a secondary cold rolled billet with a thickness of 0.2-0.3 mm; Step 8: Annealing, the annealing temperature is 380-400°C, and the annealing time is 11-13h; Step nine: The annealed billet is foil rolled and slit in sequence to obtain a finished product with a thickness of 0.02-0.03 mm. The interval time between the last two passes of foil rolling is controlled to be more than 24 hours.

[0006] Furthermore, in step 1, the cold material is composed of pure aluminum ingots and 3003 cathode foil waste, and the mass percentage of pure aluminum ingots in the cold material is 20%-30%, preferably 25%. The present invention increases the proportion of pure aluminum ingots in the cold material, directly reduces the generation of slag in the furnace, significantly reduces unnecessary slag removal operations, and thus avoids unnecessary loss of aluminum liquid weight.

[0007] Furthermore, in step 1, the mass ratio of the cold material to the electrolytic aluminum water is 1-2:1, preferably 1:1, and the smelting temperature is 740-760°C, preferably 750°C.

[0008] Furthermore, the preheated argon temperature is 190-210°C, preferably 200°C, and the preheated argon pressure is 0.2-0.3Mpa, preferably 0.25Mpa. Using argon refining can effectively remove impurities in the aluminum liquid and purify the aluminum liquid. Argon is environmentally friendly and safe, and no harmful gases are generated during the refining process, which can reduce the adverse effects on workers' health and pollution to the environment.

[0009] Furthermore, in step 2 and step 3, preheated argon gas is introduced into the aluminum alloy melt from a position 90-110 mm above the bottom of the smelting furnace.

[0010] Furthermore, in step 2, the temperature of the initial "Z"-shaped refining is 740-750°C, preferably 740°C, and the duration of the initial "Z"-shaped refining is 20-30 minutes, preferably 25 minutes. The "Z"-shaped refining is an operation of blowing argon by moving the argon blowing gun along a zigzag path.

[0011] Furthermore, in step 3, the pouring temperature is 720-730° C., preferably 725° C. Pouring the crude refined aluminum liquid into the holding furnace provides a suitable temperature for the standing and refining of the aluminum liquid, so as to ensure that the composition and temperature of the aluminum liquid meet the casting requirements and improve the quality of the aluminum liquid.

[0012] Furthermore, in step 3, preheated argon is introduced into the aluminum alloy liquid once every 3.5-4.5 hours until the surface of the aluminum alloy liquid is mirror-like, and the refining temperature is 730-740°C, preferably 730°C, which is lower than the temperature of the initial "Z"-shaped refining. During the process of introducing preheated argon into the aluminum alloy liquid, the bubble height is controlled to be less than 10 cm.

[0013] Furthermore, in step 4, the grain refiner is titanium wire, and the amount of the grain refiner added is 2.0-2.3kg / tAl, preferably 2.2kg / tAl; the target hydrogen content of online degassing is ≤0.12ml / 100g Al, and the filtration adopts a double filter plate, the aperture of the front filter plate is 40ppi, and the aperture of the rear filter plate is 50ppi. The use of a double filter plate can effectively intercept micro-impurities in the aluminum liquid, prevent foreign matter from mixing into the casting and rolling area, and avoid problems such as foreign matter pressing into or rolling leakage in the foil during the subsequent rolling process. It not only greatly improves the purity of the finished product, but also effectively guarantees the continuity and stability of production, and improves the overall quality and yield rate of the product.

[0014] Furthermore, in step seven, the reduction ratio of the secondary cold rolling is ≥98%, preferably 98%.

[0015] The beneficial effects of the present invention are: The method for eliminating the surface stripes of 3003 cathode foil provided by the present invention improves the casting performance of the aluminum alloy material and refines the microstructure of the aluminum alloy material by regulating the proportion of elements such as Si, Fe, Cu, Mn, Mg, Zn and Ti in the aluminum alloy melt; using preheated argon gas is conducive to reducing the temperature difference between argon gas and the aluminum alloy melt, and passing the preheated argon gas into the aluminum alloy liquid from the top of the bottom of the smelting furnace can avoid the temperature fluctuation of the upper and lower surfaces of the aluminum alloy liquid caused by the introduction of argon gas, so that the temperature distribution of the upper and lower surfaces of the aluminum alloy liquid is more uniform, and the refining effect of the aluminum alloy is guaranteed; adding a grain refiner to the refined aluminum liquid, and then performing online removal The gas further refines the grains and improves the purity of the aluminum liquid; the front box temperature and casting speed of the casting and rolling process are regulated, which not only avoids the tropical effect and the risk of roller sticking caused by too fast casting and rolling rate, but also ensures the stability of the casting and rolling process and the controllability of the longitudinal thickness difference. The problems of uneven heat distribution and roller surface adhesion in the surface casting and rolling process are significantly enhanced, which significantly enhances the stability of the casting and rolling operation and the thickness consistency of the product, and lays a solid foundation for subsequent processing; the present invention also sets the initial cold rolling and trimming, secondary cold rolling, annealing, foil rolling and slitting processes, and regulates the relevant process parameters to make the pressure of the aluminum alloy material more uniform.

[0016] The present invention optimizes the composition and proportion of the aluminum alloy material, refines the internal structure of the aluminum alloy material, and improves the heating uniformity and pressure uniformity of the aluminum alloy material, eliminating the surface stripes of the aluminum alloy product without reducing the mechanical properties and specific volume of the aluminum alloy product. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a surface photograph of the finished foil obtained in Example 1.

[0019] Figure 2 This is a surface photograph of the finished foil obtained in Example 2.

[0020] Figure 3 This is a surface photograph of the finished foil obtained in Example 3.

[0021] Figure 4 This is a surface photograph of the finished foil obtained in Comparative Example 1.

[0022] Figure 5 This is a surface photograph of the finished foil obtained in Comparative Example 2.

[0023] Figure 6This is the microstructure diagram of the aluminum liquid in Example 1. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0025] Example 1 A method for eliminating stripes on the surface of 3003 cathode foil comprises the following steps: Step 1: Add the cold material to the electrolytic aluminum water and melt it at 750℃, then stir, sample and detect the composition of the aluminum alloy melt, and then make the proportion of the components until the composition of the aluminum alloy melt is as follows in terms of mass percentage: Si: 0.096%, Fe: 0.3%, Cu: 0.11%, Mn: 1.2%, Mg: 0.01%, Zn: 0.01%, Ti: 0.028%, and the balance is Al. The cold material is composed of high-purity aluminum ingots and self-produced 3003 cathode foil waste, and the mass percentage of high-purity aluminum ingots in the cold material is 25%. The mass ratio of cold material to electrolytic aluminum water is 1:1.

[0026] Step 2: At 740°C, argon gas preheated to 200°C with a purity of 99.5% or above is extended into the aluminum alloy melt at a position 100mm away from the bottom of the melting furnace, and is introduced into the aluminum alloy melt for initial "Z"-shaped refining for 25 minutes. The "Z"-shaped refining is to move the argon blowing gun along a Z-shaped path to blow argon, and then skim off the slag to ensure that the surface of the melt is mirror-like to obtain coarse refined aluminum liquid. The pressure of the preheated argon gas is 0.25Mpa.

[0027] Step 3: Pour the crude refined aluminum liquid into the holding furnace and continue refining in the holding furnace. The pouring furnace temperature is 725℃. At 730℃, the argon gas preheated to 200℃ and with a purity of 99.5% or above is extended into the position 100mm from the bottom of the holding furnace, and passed into the crude refined aluminum liquid for "Z"-shaped refining for 25min again. During the refining process, the bubble height is controlled to be less than 10cm. Repeat the refining operation in the holding furnace every 4h until the surface of the aluminum alloy liquid is mirror-like and refined aluminum liquid is obtained. The pressure of the preheated argon gas is 0.25Mpa.

[0028] Step 4: Add titanium wire to the refined aluminum liquid for grain refinement. The amount of titanium wire added is 2.2kg / tAl. After the grain refinement treatment, the refined aluminum liquid enters the Mitsui 1B1R online degassing device for online degassing and filtration. The online degassing device is equipped with double filter plates. The aperture of the front filter plate is 40ppi, and the aperture of the rear filter plate is 50ppi. The target hydrogen content of online degassing is ≤0.12ml / 100g Al, and the aluminum liquid with a grain size of level 1 is obtained. The microstructure diagram of the aluminum liquid is as follows: Figure 6 shown.

[0029] Step 5: Casting and rolling. The front box temperature is controlled at 700°C and the casting and rolling speed is 800 mm / min to obtain a billet with a thickness of 7 mm.

[0030] Step 6: The billet is cold rolled for 4 passes. To prevent the cracked edge from affecting the rolling roller, the cold rolled billet is trimmed. After the trimming in the middle of the billet is completed, the cracked edge of the billet is completely removed, ensuring the smooth progress of the subsequent processing process. After the trimming process, the initial cold rolled billet is obtained.

[0031] Step 7: The primary cold-rolled billet is subjected to secondary cold rolling at a reduction rate of 98% to obtain a secondary cold-rolled billet with a thickness of 0.22 mm.

[0032] Step 8: Annealing, keep the material temperature at 390°C for 12 hours.

[0033] Step nine: The annealed billet is foil rolled and slit in sequence to obtain a finished product with a thickness of 0.03 mm. Three consecutive rolling passes are avoided during the foil rolling process, and the interval time between the last two passes of foil rolling is controlled to be more than 24 hours.

[0034] Example 2 A method for eliminating stripes on the surface of 3003 cathode foil comprises the following steps: Step 1: Add the cold material to the electrolytic aluminum water and melt it at 755℃, then stir, sample and detect the composition of the aluminum alloy melt, and then make the proportion until the composition of the aluminum alloy melt is as follows in mass percentage: Si: 0.09%, Fe: 0.2%, Cu: 0.15%, Mn: 1.5%, Mg: 0.01%, Zn: 0.01%, Ti: 0.01%, and the balance is Al. The cold material is composed of high-purity aluminum ingots and self-produced 3003 cathode foil waste, and the mass percentage of high-purity aluminum ingots in the cold material is 27%. The mass ratio of cold material to electrolytic aluminum water is 1:1.

[0035] Step 2: At 745°C, argon gas preheated to 200°C with a purity of 99.5% or above is extended into the aluminum alloy melt at a position 100mm away from the bottom of the melting furnace, and is introduced into the aluminum alloy melt for initial "Z"-shaped refining for 28 minutes. The "Z"-shaped refining is to move the argon blowing gun along a Z-shaped path to blow argon, and then skim off the slag to ensure that the surface of the melt is mirror-like to obtain coarse refined aluminum liquid. The pressure of the preheated argon gas is 0.3Mpa.

[0036] Step 3: Pour the crude refined aluminum liquid into the holding furnace and continue refining in the holding furnace. The pouring furnace temperature is 730℃. At 735℃, the argon gas preheated to 200℃ and with a purity of 99.5% or above is extended into the position 100mm from the bottom of the holding furnace, and passed into the crude refined aluminum liquid for "Z"-shaped refining for 28min. During the refining process, the bubble height is controlled to be less than 10cm. Repeat the refining operation in the holding furnace every 4h until the surface of the aluminum alloy liquid is mirror-like and refined aluminum liquid is obtained. The pressure of the preheated argon gas is 0.3Mpa.

[0037] Step 4: Add titanium wire to the refined aluminum liquid for grain refinement, and the amount of titanium wire added is 2.3kg / tAl. After the grain refinement treatment, the refined aluminum liquid enters the Mitsui 1B1R online degassing device for online degassing and filtration. The online degassing device is equipped with double filter plates, the aperture of the front filter plate is 40ppi, and the aperture of the rear filter plate is 50ppi. The target hydrogen content of online degassing is ≤0.12ml / 100g Al, and aluminum liquid with a grain size of level one is obtained.

[0038] Step 5: Casting and rolling. The front box temperature is controlled at 695°C and the casting and rolling speed is 810 mm / min to obtain a billet with a thickness of 8 mm.

[0039] Step 6: The billet is cold rolled for 4 passes. To prevent the cracked edge from affecting the rolling roller, the cold rolled billet is trimmed. After the trimming in the middle of the billet is completed, the cracked edge of the billet is completely removed, ensuring the smooth progress of the subsequent processing process. After the trimming process, the initial cold rolled billet is obtained.

[0040] Step 7: The primary cold-rolled billet is subjected to secondary cold rolling at a reduction rate of 98% to obtain a secondary cold-rolled billet with a thickness of 0.26 mm.

[0041] Step 8: Annealing, keep the material temperature at 392°C for 12 hours.

[0042] Step nine: The annealed billet is foil rolled and slit in sequence to obtain a finished product with a thickness of 0.03 mm. Three consecutive rolling passes are avoided during the foil rolling process, and the interval time between the last two passes of foil rolling is controlled to be more than 24 hours.

[0043] Example 3 A method for eliminating stripes on the surface of 3003 cathode foil comprises the following steps: Step 1: Add the cold material to the electrolytic aluminum water and melt it at 755℃, then stir, sample and detect the composition of the aluminum alloy melt, and then make the proportion until the composition of the aluminum alloy melt is as follows in mass percentage: Si: 0.08%, Fe: 0.5%, Cu: 0.13%, Mn: 1.5%, Mg: 0.03%, Zn: 0.02%, Ti: 0.02%, and the balance is Al. The cold material is composed of high-purity aluminum ingots and self-produced 3003 cathode foil waste, and the mass percentage of high-purity aluminum ingots in the cold material is 30%. The mass ratio of cold material to electrolytic aluminum water is 2:1.

[0044] Step 2: At 750°C, argon gas preheated to 200°C with a purity of 99.5% or above is extended into the aluminum alloy melt at a position 100mm away from the bottom of the melting furnace, and then blown into the aluminum alloy melt for the first "Z"-shaped refining for 30 minutes. The "Z"-shaped refining is to move the argon blowing gun along a Z-shaped path to blow argon, and then skim off the slag to ensure that the surface of the melt is mirror-like to obtain coarse refined aluminum liquid. The pressure of the preheated argon gas is 0.23Mpa.

[0045] Step 3: Pour the crude refined aluminum liquid into the holding furnace and continue refining in the holding furnace. The pouring furnace temperature is 722℃. At 740℃, the argon gas preheated to 200℃ and with a purity of 99.5% or more is extended into the position 100mm from the bottom of the holding furnace, and passed into the crude refined aluminum liquid for "Z"-shaped refining for 30min again. During the refining process, the bubble height is controlled to be less than 10cm. Repeat the refining operation in the holding furnace every 4h until the surface of the aluminum alloy liquid is mirror-like and refined aluminum liquid is obtained. The pressure of the preheated argon gas is 0.23Mpa.

[0046] Step 4: Add titanium wire to the refined aluminum liquid for grain refinement, and the amount of titanium wire added is 2.1kg / tAl. The refined aluminum liquid after grain refinement enters the Mitsui 1B1R online degassing device for online degassing and filtration. The online degassing device is installed with double filter plates, the aperture of the front filter plate is 40ppi, and the aperture of the rear filter plate is 50ppi. The target hydrogen content of online degassing is ≤0.12ml / 100g Al, and aluminum liquid with a grain size of level one is obtained.

[0047] Step 5: Casting and rolling. The front box temperature is controlled at 700°C and the casting and rolling speed is 795 mm / min to obtain a billet with a thickness of 6.5 mm.

[0048] Step 6: The billet is cold rolled for 4 passes. To prevent the cracked edge from affecting the rolling roller, the cold rolled billet is trimmed. After the trimming in the middle of the billet is completed, the cracked edge of the billet is completely removed, ensuring the smooth progress of the subsequent processing process. After the trimming process, the initial cold rolled billet is obtained.

[0049] Step 7: The primary cold-rolled billet is subjected to secondary cold rolling at a reduction rate of 98% to obtain a secondary cold-rolled billet with a thickness of 0.28 mm.

[0050] Step 8: Annealing, keep the material temperature at 388°C for 12 hours.

[0051] Step nine: The annealed billet is foil rolled and slit in sequence to obtain a finished product with a thickness of 0.02 mm. Three consecutive rolling passes are avoided during the foil rolling process, and the interval time between the last two passes of foil rolling is controlled to be more than 24 hours.

[0052] The bending times, tensile force and specific volume of the finished foils obtained in Examples 1 to 3, the standard sample 1 of 3003 aluminum alloy foil with a thickness of 0.026 mm, and the standard sample 2 of 3003 aluminum alloy foil with a thickness of 0.02 mm were tested respectively, and the stripes on the foil surface of each sample were observed. The results are shown in Table 1. The stripes on the foil surface of the finished foils obtained in Examples 1 to 3 are shown in Table 1. Figure 1-Figure 3 shown.

[0053] Table 1 Test results of finished foils obtained in Examples 1-3 and 3003 aluminum alloy foil standard samples

[0054] Comparative Example 1 A method for eliminating stripes on the surface of 3003 cathode foil comprises the following steps: Step 1: Add the cold material to the electrolytic aluminum water and melt it at 750℃, then stir, sample and detect the composition of the aluminum alloy melt, and then make the proportion of the components until the composition of the aluminum alloy melt is as follows in terms of mass percentage: Si: 0.096%, Fe: 0.3%, Cu: 0.11%, Mn: 1.2%, Mg: 0.01%, Zn: 0.01%, Ti: 0.028%, and the balance is Al. The cold material is composed of high-purity aluminum ingots and self-produced 3003 cathode foil waste, and the mass percentage of high-purity aluminum ingots in the cold material is 25%. The mass ratio of cold material to electrolytic aluminum water is 1:1.

[0055] Step 2: At 740°C, argon gas preheated to 200°C with a purity of 99.5% or above is extended into the aluminum alloy melt at a position 100mm away from the bottom of the melting furnace, and is introduced into the aluminum alloy melt for initial "Z"-shaped refining for 25 minutes. The "Z"-shaped refining is to move the argon blowing gun along a Z-shaped path to blow argon, and then skim off the slag to ensure that the surface of the melt is mirror-like to obtain coarse refined aluminum liquid. The pressure of the preheated argon gas is 0.25Mpa.

[0056] Step 3: Pour the crude refined aluminum liquid into the holding furnace and continue refining in the holding furnace. The pouring furnace temperature is 725℃. At 730℃, the argon gas preheated to 200℃ and with a purity of 99.5% or above is extended into the position 100mm from the bottom of the holding furnace, and passed into the crude refined aluminum liquid for "Z"-shaped refining for 25min again. During the refining process, the bubble height is controlled to be less than 10cm. Repeat the refining operation in the holding furnace every 4h until the surface of the aluminum alloy liquid is mirror-like and refined aluminum liquid is obtained. The pressure of the preheated argon gas is 0.25Mpa.

[0057] Step 4: Add titanium wire to the refined aluminum liquid for grain refinement, and the amount of titanium wire added is 2.2kg / tAl. The refined aluminum liquid after grain refinement enters the Mitsui 1B1R online degassing device for online degassing and filtration. A double filter plate is installed in the online degassing device. The aperture of the front filter plate is 40ppi, and the aperture of the rear filter plate is 50ppi. The target hydrogen content of online degassing is ≤0.12ml / 100g Al, and aluminum liquid with a grain size of level one is obtained.

[0058] Step 5: Casting and rolling. The front box temperature is controlled at 700°C and the casting and rolling speed is 800 mm / min to obtain a billet with a thickness of 7 mm.

[0059] Step 6: The billet is cold rolled for 4 passes. To prevent the cracked edge from affecting the rolling roller, the cold rolled billet is trimmed. After the trimming in the middle of the billet is completed, the cracked edge of the billet is completely removed, ensuring the smooth progress of the subsequent processing process. After the trimming process, the initial cold rolled billet is obtained.

[0060] Step 7: The primary cold-rolled billet is subjected to secondary cold rolling at a reduction rate of 91% to obtain a secondary cold-rolled billet with a thickness of 0.6 mm.

[0061] Step 8: Annealing, keep the material temperature at 350°C for 5 hours.

[0062] Step nine: The annealed billet is foil rolled and slit in sequence to obtain a finished product with a thickness of 0.02 mm. Three consecutive rolling passes are avoided during the foil rolling process, and the interval time between the last two passes of foil rolling is controlled to be more than 24 hours.

[0063] The bending times, tensile force and specific volume of the finished foil obtained in comparative example 1 and the standard sample 2 of 3003 aluminum alloy foil with a thickness of 0.02 mm were tested respectively, and the stripes on the foil surface of each sample were observed. The results are shown in Table 2. The stripes on the foil surface of the finished foil obtained in comparative example 1 are shown in Table 2. Figure 4 shown.

[0064] Table 2 Test results of finished foil obtained in Comparative Example 1 and 3003 aluminum alloy foil standard sample

[0065] As can be seen from Table 2, the surface of the finished foil obtained in Comparative Example 1 has no stripes, but the specific volume is lower than that of the standard sample 2 with the same thickness.

[0066] Comparative Example 2 A method for eliminating stripes on the surface of 3003 cathode foil comprises the following steps: Step 1: Add the cold material to the electrolytic aluminum water and melt it at 750℃, then stir, sample and detect the composition of the aluminum alloy melt, and then make the proportion until the composition of the aluminum alloy melt is as follows in mass percentage: Si: 0.08%, Fe: 0.3%, Cu: 0.11%, Mn: 1.2%, Mg: 0.01%, Zn: 0.01%, Ti: 0.028%, and the balance is Al. The cold material is composed of high-purity aluminum ingots and self-produced 3003 cathode foil waste, and the mass percentage of high-purity aluminum ingots in the cold material is 25%. The mass ratio of cold material to electrolytic aluminum water is 1:1.

[0067] Step 2: At 740°C, argon gas preheated to 200°C with a purity of 99.5% or above is extended into the aluminum alloy melt at a position 100mm away from the bottom of the melting furnace, and is introduced into the aluminum alloy melt for initial "Z"-shaped refining for 25 minutes. The "Z"-shaped refining is to move the argon blowing gun along a Z-shaped path to blow argon, and then skim off the slag to ensure that the surface of the melt is mirror-like to obtain coarse refined aluminum liquid. The pressure of the preheated argon gas is 0.25Mpa.

[0068] Step 3: Pour the crude refined aluminum liquid into the holding furnace and continue refining in the holding furnace. The pouring furnace temperature is 725℃. At 730℃, the argon gas preheated to 200℃ and with a purity of 99.5% or above is extended into the position 100mm from the bottom of the holding furnace, and passed into the crude refined aluminum liquid for "Z"-shaped refining for 25min again. During the refining process, the bubble height is controlled to be less than 10cm. Repeat the refining operation in the holding furnace every 4h until the surface of the aluminum alloy liquid is mirror-like and refined aluminum liquid is obtained. The pressure of the preheated argon gas is 0.25Mpa.

[0069] Step 4: Add titanium wire to the refined aluminum liquid for grain refinement, and the amount of titanium wire added is 2.2kg / tAl. The refined aluminum liquid after grain refinement enters the Mitsui 1B1R online degassing device for online degassing and filtration. A double filter plate is installed in the online degassing device. The aperture of the front filter plate is 40ppi, and the aperture of the rear filter plate is 50ppi. The target hydrogen content of online degassing is ≤0.12ml / 100g Al, and aluminum liquid with a grain size of level one is obtained.

[0070] Step 5: Casting and rolling. The front box temperature is controlled at 700°C and the casting and rolling speed is 800 mm / min to obtain a billet with a thickness of 7.0 mm.

[0071] Step 6: The blank is cold rolled once to obtain a cold rolled blank with a thickness of 4.0 mm.

[0072] Step 7: Annealing, keep the material temperature at 580°C for 3 hours.

[0073] Step 8: After annealing, the aluminum alloy material is further cold rolled at a reduction rate of 96% until the predetermined thickness of 0.22 mm is reached.

[0074] Step 9: Anneal again and keep the material temperature at 350℃ for 5h.

[0075] Step 10: The annealed billet is foil rolled and slit in sequence to obtain a finished product with a thickness of 0.03 mm. Three consecutive rolling passes are avoided during the foil rolling process, and the interval time between the last two passes of foil rolling is controlled to be more than 24 hours.

[0076] The bending times, tensile force and specific volume of the finished foil obtained in comparative example 2 and the standard sample 2 of 3003 aluminum alloy foil with a thickness of 0.02 mm were tested respectively, and the stripes on the foil surface of each sample were observed. The results are shown in Table 3. Figure 5 As shown, Figure 5 In the test, there are many coarse stripes of irregular lengths perpendicular to the rolling direction on the foil surface of the finished foil, and the stripes on the foil surface are serious.

[0077] Table 3 Test results of finished foil obtained in Comparative Example 2 and 3003 aluminum alloy foil standard sample

[0078] It can be seen from Table 3 that the surface of the finished foil obtained in Comparative Example 2 has stripe defects.

[0079] Although the present invention has been described in detail with reference to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention.

Claims

1. A method for eliminating surface stripes on 3003 cathode foil, characterized in that: The steps include: Step 1: adding cold material into electrolytic aluminum water for smelting to obtain aluminum alloy melt, the composition of the aluminum alloy melt is as follows by mass percentage: Si≤0.1%, Fe: 0.2%-0.5%, Cu: 0.10%-0.15%, Mn: 1.0%-1.5%, Mg≤0.05%, Zn≤0.05%, Ti: 0.01%-0.03%, and the balance is Al; Step 2: Preheated argon gas is introduced into the aluminum alloy melt from the bottom of the melting furnace to perform initial "Z"-shaped refining, and then the slag is removed to obtain a crude refined aluminum liquid; Step 3: Pour the crude refined aluminum liquid into a holding furnace, and intermittently introduce preheated argon gas from the top of the bottom of the holding furnace into the crude refined aluminum liquid for "Z"-shaped refining to obtain refined aluminum liquid; Step 4: adding a grain refiner to the refined aluminum liquid for grain refinement, and then performing online degassing and filtration to obtain aluminum liquid with a first-grade grain size; Step 5: Casting and rolling, controlling the front box temperature to 680-700°C and the casting and rolling speed to 790-810 mm / min, to obtain a billet with a thickness of 6.5-8 mm; Step 6: cold rolling the blank for 4 passes, and then trimming the blank to obtain the primary cold rolled blank; Step 7: performing secondary cold rolling on the primary cold rolled billet to obtain a secondary cold rolled billet with a thickness of 0.2-0.3 mm; Step 8: Annealing, the annealing temperature is 380-400°C, and the annealing time is 11-13h; Step nine: The annealed billet is foil rolled and slit in sequence to obtain a finished product with a thickness of 0.02-0.03 mm. The interval time between the last two passes of foil rolling is controlled to be more than 24 hours.

2. A method for eliminating stripes on the surface of 3003 cathode foil as claimed in claim 1, characterized in that: In step 1, the cold material consists of pure aluminum ingots and 3003 cathode foil scrap, and the mass percentage of the pure aluminum ingots in the cold material is 20%-30%.

3. A method for eliminating stripes on the surface of 3003 cathode foil as claimed in claim 1, characterized in that: In step 1, the mass ratio of cold material to electrolytic aluminum water is 1-2:1, and the smelting temperature is 740-760°C.

4. A method for eliminating stripes on the surface of 3003 cathode foil as claimed in claim 1, characterized in that: In step 2 and step 3, the temperature of the preheated argon gas is 190-210° C., and the pressure of the preheated argon gas is 0.2-0.3 MPa.

5. A method for eliminating stripes on the surface of 3003 cathode foil as claimed in claim 1, characterized in that: In step 2 and step 3, preheated argon gas is introduced into the aluminum alloy melt from a position 90-110 mm above the bottom of the melting furnace.

6. A method for eliminating stripes on the surface of 3003 cathode foil as claimed in claim 1, characterized in that: In step 2, the temperature of the initial "Z"-shaped refining is 740-750°C, and the duration of the initial "Z"-shaped refining is 20-30 minutes.

7. A method for eliminating stripes on the surface of 3003 cathode foil as claimed in claim 1, characterized in that: In step 3, the pouring furnace temperature is 720-730°C.

8. A method for eliminating stripes on the surface of 3003 cathode foil as claimed in claim 1, characterized in that: In step 3, preheated argon gas is introduced into the aluminum alloy liquid once every 3.5-4.5 hours until the surface of the aluminum alloy liquid becomes mirror-like and the refining temperature is 730-740°C.

9. A method for eliminating stripes on the surface of 3003 cathode foil as claimed in claim 1, characterized in that: In step 4, the grain refiner is titanium wire, and the amount of the grain refiner added is 2.0-2.3 kg / tAl; the target hydrogen content of the online degassing is ≤0.12 ml / 100 g Al.

10. A method for eliminating stripes on the surface of 3003 cathode foil as claimed in claim 1, characterized in that: In step seven, the reduction ratio of the secondary cold rolling is ≥98%.

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