Method for manufacturing 5052 aluminum sheet

Abstract

The present invention relates to a method for manufacturing an aluminum plate material, which shortens a process and working hours to improve productivity, and more particularly, to a method for manufacturing an aluminum plate material, which, after being extruded to a desired thickness, is calendered, thereby shortening the number of calendering times and working hours required for a manufacturing process, which is performed only by calendering in the prior art, shortening the manufacturing process and working hours, and improving productivity.

Description

Technical Field

[0001] This invention relates to a method for manufacturing aluminum sheets, specifically a method for manufacturing coils by extrusion and then rolling the coils. In the past, when rolling extruded coils, breakage occurred at the joint (connecting part) of the blank, so it was generally believed that it was impossible to roll extruded coils. However, this invention improves the process so that extruded coils can be rolled, thereby significantly reducing the number of steps and time, and increasing productivity.

[0002] In particular, the aluminum sheet manufacturing method of the present invention involves extruding to the required thickness and then rolling, thereby reducing the number of rolling operations and time required for the manufacturing process that previously consisted only of rolling, shortening the manufacturing process and time, and improving productivity. Background Technology

[0003] Aluminum is lightweight and easy to cast, readily forms alloys with other metals, is easy to process at both room temperature and high temperature, and has excellent electrical and thermal conductivity, making it widely used throughout the industry.

[0004] On the one hand, regarding automobiles, in order to address various problems such as environmental pollution caused by the overuse of fossil fuels, electric vehicles (EVs), fuel cell vehicles (FCEVs), and hybrid electric vehicles (HEVs) that combine the characteristics of internal combustion engines and electric vehicles are being developed. All of these vehicles must use batteries.

[0005] Batteries mainly use nickel batteries, lithium batteries, etc., which are structures that use materials such as anode materials, cathode materials, electrolytes, and separation membranes to convert electrical energy into chemical energy for storage, and then convert chemical energy back into electrical energy for use.

[0006] Aluminum is used in a variety of fields, including battery housings, battery encapsulation shells and various frames of vehicles as described above. This aluminum is rolled into coils at a specified thickness and then supplied to the production lines that manufacture various components.

[0007] Currently, various methods for manufacturing components using this type of aluminum sheet are being developed, and examples of sheet manufacturing are found in patent documents 1-3.

[0008] Patent Document 1 discloses a method for manufacturing aluminum alloy sheet, comprising: a sheet casting step, including an injection mechanism setting process in which nozzles of symmetrical or asymmetrical shapes for guiding AA5083 alloy molten metal are set in contact with each other on one side of a pair of rollers and a molten metal injection mechanism; a roller rotation process in which rotational power is provided to the pair of rollers to rotate in opposite directions; a molten metal supply process in which AA5083 alloy molten metal is supplied to the inside of the molten metal injection mechanism; a molten metal injection process in which the AA5083 alloy molten metal supplied to the molten metal injection mechanism is injected into the space between the pair of rollers; a molten metal solidification process in which the AA5083 alloy molten metal injected into the space between the pair of rollers is pressurized and solidified; a rotational speed changing process in which the rotational speed of the rollers is selectively changed according to the change in the roll separation force applied to the pair of rollers during the molten metal solidification process; and a sheet drawing process in which the solidified aluminum alloy sheet is drawn out from the pair of rollers; a rolling step in which the alloy sheet is rolled; and a heat treatment step in which the rolled alloy sheet is heat treated to form grains of less than 10 μm and precipitates on Al6Mn of less than 20 nm.

[0009] Patent Document 2 discloses a method for rolling aluminum alloy sheets, comprising: a raw material introduction step, in which aluminum alloy raw material is introduced into a cross-rolling mill, the cross-rolling mill having multiple roll units, wherein the multiple roll units are provided with upper cross rolls and lower cross rolls whose center lines are arranged to intersect each other so as to roll the aluminum alloy raw material; and a cross-rolling step, wherein the aluminum alloy raw material is rolled simultaneously as it passes through the upper cross rolls and the lower cross rolls. The upper cross rolls and the lower cross rolls are inclined relative to the normal to the direction in which the aluminum alloy raw material is introduced, the roll units are arranged sequentially along the direction in which the aluminum alloy raw material is introduced, and the upper cross rolls and lower cross rolls of adjacent roll units are inclined in opposite directions relative to the normal to the direction in which the aluminum alloy raw material is introduced.

[0010] Patent document 3 discloses a method for manufacturing aluminum alloy sheets, which includes a step of rolling an aluminum alloy sheet composed of Si: 0.71%, Fe: 0.5%, Cu: 0.24%, Mn: 0.12%, Mg: 0.9% by weight, with the balance Al and unavoidable trace impurities, between an upper roll and a lower roll with different rotational speed ratios. The thickness reduction percentage is 45-55%, the speed of the lower roll is 2.7-6.2 mpm (meters per minute), and the rolling process is performed at a different speed ratio of 1:2.7-3.3 between the rotational speeds of the opposing lower roll and the upper roll.

[0011] As mentioned above, although various technologies for manufacturing aluminum sheets have been developed, these technologies typically involve melting and alloying, casting thick plates (slabs), repeatedly hot rolling the cast thick plates dozens of times to achieve a specified thickness, and then repeatedly cold rolling them several times to form thinner plates.

[0012] That is, the general method of manufacturing aluminum sheets is to manufacture them through one of the processes of rolling or extrusion. The rolling method is as described above, while the extrusion method is as follows: after casting the billet, it is extruded into the required thickness through an extrusion die.

[0013] In this aluminum sheet manufacturing method, rolling is the process of forming a sheet of uniform thickness. It is a method of making a thick metal plate or sheet thin and flat by placing it between rolls. Although a sheet of uniform thickness has the advantage of being able to obtain a wide width, it has the disadvantage of not being able to form curved or tubular hollow shapes like the extrusion method. Since it only has a certain thickness on one cross section, the thickness can only be changed by stacking through bending, welding, forging or cutting. Therefore, there is a disadvantage that subsequent processing steps are required.

[0014] Furthermore, in the rolling process, the DC process, which produces sheet metal after casting thick plates, or the CC process, which produces sheet metal using molten metal, cannot produce sheet metal of the desired thickness in just one operation. It requires several or dozens of passes through the rolling mill to gradually reduce the thickness. In order to produce the required product thickness, several rounds of rolling and heat treatment are required. Therefore, the manufacturing process is complex and requires a lot of time.

[0015] On the other hand, although the extrusion method has the advantages of being able to produce various cross-sectional shapes and different thicknesses in different parts of the cross-section, the extrusion die causes elastic deformation of the blank and the extrusion pressure. This results in a cross-section that is slightly thicker when the pressure is higher in the early stage and slightly thinner when the pressure is reduced in the later stage. Thickness deviations may also occur in different parts of the extruded cross-section. Since it is a hot process, there are problems such as product distortion and shrinkage during the cooling process after hot processing, depending on the degree of heat dissipation.

[0016] Furthermore, although extrusion is a plastic processing method, it differs from calendering in that it forms the cross-section of the product in one step through a die. Therefore, the minimum thickness achievable through extrusion varies depending on the material and shape. In the case of a typical square tube, the minimum thickness of 1000 series alloys is 0.8 mm, and the minimum thickness of 6000 series alloys is about 1.0 mm. This range is limited, and further processing is required to manufacture products with thinner thicknesses. As a result, it has the disadvantage of only being able to produce products with a certain cross-section.

[0017] Furthermore, although there have been many attempts to roll extruded sheets into coils, impurities such as oxides, media, and foreign matter cannot be well controlled from the melting and casting stages. In particular, in the case of high-strength alloy 5052, which contains 2.2~2.8wt% magnesium, due to oxidation problems during high-temperature extrusion, extrusion is not carried out at temperatures above 500°C, but at temperatures below 500°C. As a result, the bonding force of the billet connection (joint part) is small during rolling, leading to breakage. Therefore, it is generally accepted that continuous rolling of extruded sheets is impossible.

[0018] [Prior Technology Documents]

[0019] [Patent Literature]

[0020] (Patent Document 0001) Korean Patent Publication No. 10-2010-0104731.

[0021] (Patent Document 0002) Korean Patent Publication No. 10-2011-0114101.

[0022] (Patent Document 0003) Korean Patent Publication No. 10-2015-0094983. Summary of the Invention

[0023] The technical issues to be solved

[0024] The present invention was developed to solve the problems of the prior art as described above, and its purpose is to provide a method for manufacturing aluminum sheet as follows: after casting a billet, a coil based on continuous extrusion is produced and the coil is rolled, thereby significantly reducing the number of processes and working time to improve productivity.

[0025] In particular, the object of the present invention is to provide a method for manufacturing sheet metal in which impurities (oxides, media, foreign matter) are removed during the melting and casting stages, and a blank is cast after a purification process. The purified blank is then subjected to high-temperature extrusion to prevent the inflow of foreign matter, thereby improving the bonding force of the connection part (joint part) of the blank. As a result, the blank does not break at the connection part during rolling, and all processes can be carried out continuously until rolling.

[0026] That is, the object of the present invention is to provide a method for manufacturing aluminum sheet by rolling after extrusion, thereby eliminating the problems that may occur when manufacturing by rolling alone or by extrusion alone, thereby shortening the manufacturing process and time.

[0027] Problem Solution

[0028] The present invention, for achieving the objectives described above, provides a method for manufacturing aluminum sheet using extrusion and rolling, for producing aluminum alloy sheet as a raw material for battery cans or casings. The method is characterized by comprising: a melting and alloying step, in which aluminum ingots and an alloying agent are melted and alloyed; a purification step, in which flux and nitrogen are used to remove foreign matter and stirred to control the purity of the molten metal, and the purity of the molten metal is controlled by passing a GBF and ceramic foam filter before billet casting; a billet casting step, in which billets are manufactured to a specified width, thickness, and length; and a homogenization treatment step, in which heat treatment is performed. The process includes: removing segregation generated during solidification of the billet during casting; a stripping step to process the billet surface to remove the oxide layer present on the billet surface before extrusion; a continuous hot extrusion step to extrude the billet at a high temperature of 500℃~600℃ to a thickness of 9~15mm; a coiling step to apply tension to the continuously extruded sheet while using a coiling machine to produce coils; a cold rolling step to roll the extruded aluminum alloy to a thickness of 20~30% of the extruded sheet thickness; a stretching and straightening step to pass the rolled aluminum sheet through a stretching and straightening machine to ensure the flatness of the sheet; and a cutting step to cut the flattened sheet into a workable size.

[0029] Preferably, the following steps are also implemented: an annealing step for stress relief and recrystallization of the cold-rolled aluminum sheet; and a stabilization step for restoring the material properties that increased in strength and decreased in elongation during the cold rolling step.

[0030] Preferably, the hot extrusion step described above is carried out at a pressure of 200 bar or above, at a speed of 1.0 to 5.0 mm / s, and at a temperature range of 500 to 600°C. In order to prevent oxidation during high-temperature extrusion and to prevent the sheet from overheating, it is preferable that the extrusion die and the extruder outlet are under a nitrogen atmosphere during the extrusion process.

[0031] Preferably, the above annealing step is carried out at 300~400℃ for 1~5 hours.

[0032] Preferably, the above stabilization step is carried out at 120~180°C for 1~5 hours.

[0033] Preferably, the above-mentioned winding step is performed by a winding device, which includes: a plurality of conveying rollers for conveying aluminum alloy sheets for outputting extruded sheets; a pressing roller for pressing the sheet conveyed by the conveying rollers toward the winding machine side; a winding machine having a winding drum 32 driven to rotate by a drive mechanism, on which the sheet is wound; and a guide roller for neatly winding the sheet without detaching it from the end of the winding drum.

[0034] Invention Effects

[0035] The aluminum sheet manufacturing method based on extrusion and rolling of the present invention makes a significant contribution by enabling continuous rolling of extruded sheets that were previously considered impossible to continuously roll. It reduces the time and process required for hot rolling of thick plates from several to dozens of times to a single extrusion, thereby shortening the overall process and time and improving productivity.

[0036] Furthermore, the present invention can replace hot rolling with hot extrusion, thereby making it easier to produce cold rolled sheets with a width of less than 1m. In particular, it can significantly reduce the hot rolling process of high-strength alloys such as the 2000 series, 5000 series, and 7000 series. When producing the high-strength alloys mentioned above, it has the effect of shortening the process and saving costs.

[0037] Furthermore, by extruding to a specified thickness, the present invention can compensate for thickness deviations at the beginning and end of the extrusion process, as well as thickness deviations in the cross section caused by changes in metal flow due to the shape of the product, thereby enabling the production of aluminum sheets with uniform thickness.

[0038] In particular, in this invention, the thickness during hot extrusion is relatively thicker than the thickness during hot rolling, thereby increasing the amount of cold rolling. This results in a denser structure in the rolled sheet, which in turn prevents tearing when the sheet is bent by a punch after rolling.

[0039] Furthermore, in this invention, even when a cold calendering step is performed, fewer calendered knots are generated compared to products made by hot calendering and cold calendering in the prior art, thus further reducing tearing or breakage during stamping.

[0040] Furthermore, by linking the extrusion exit speed and winding speed with the encoder, there is no need for an underground pit to prevent the winding machine from breaking due to speed differences, thus achieving the effect of reducing space requirements.

[0041] Furthermore, it has been previously believed that a tensioner is necessary to apply additional tension to the winding machine in order to secure the winding. However, in this invention, tension is naturally applied by changing the direction of the extruded sheet through the conveyor table, thereby eliminating the need for a tensioner and simplifying the equipment. Attached Figure Description

[0042] Figure 1 This is a process diagram of an aluminum sheet manufacturing method based on the present invention, utilizing extrusion and rolling.

[0043] Figure 2 The photograph shows that the blank connection part before and after rolling of the sheet manufactured by the aluminum sheet manufacturing method based on the present invention does not break.

[0044] Figure 3 This is a front view of an example of a coiling device used in a method for manufacturing aluminum sheet by extrusion and rolling based on the present invention.

[0045] The reference numerals in the attached figures are explained as follows:

[0046] 10: Conveyor roller; 20: Pressing roller; 30: Winder; 31: Drive mechanism; 32: Winding drum; 32g: Grooving; 40: Guide mechanism; 41: Push roller; 41r: Rotating roller; 42: Guide plate; 43: Rotating mechanism; 43s: Rotating shaft; 43c: Working cylinder; 50: Coil discharge mechanism; 51: Coil trolley; 52: Guide rail; 53: Drive mechanism. Detailed Implementation

[0047] This invention can be implemented in various ways. Here, specific embodiments are shown in the figures and described in detail. However, this is not intended to limit the invention to a particular embodiment, but should be understood to include all modifications, equivalents, and substitutions that fall within the scope of the ideas and techniques of this invention.

[0048] In illustrating the figures, similar reference numerals are used for similar constituent elements. In describing this invention, detailed descriptions of related prior art are omitted where such descriptions might obscure the main points of the invention.

[0049] This invention can reduce the manufacturing process and time of aluminum sheets, and improve productivity.

[0050] The aluminum sheet manufacturing method based on the present invention, which utilizes extrusion and rolling, can be applied to the casting of various aluminum alloys, but is preferably suitable for manufacturing aluminum 5052 sheets used in the manufacture of battery casings, cans, and packaging shells.

[0051] The following explanation will be based on the manufacturing of 5052 aluminum sheet.

[0052] The present invention relates to a method for manufacturing aluminum sheet using extrusion and rolling, which is a method for manufacturing aluminum alloy sheet as raw material for battery cans or casings. The method includes: a step of melting and alloying aluminum ingots and alloying agents; a purification step, in which flux and nitrogen are used to remove foreign matter and agitated to control the purity of the molten metal; and, before billet casting, the purity of the molten metal is controlled by using a GBF and ceramic foam filter; a billet casting step, in which billets are manufactured to a specified width, thickness, and length; and a homogenization treatment step, in which heat treatment is performed to remove impurities from the billet casting process. Segregation occurs during solidification; a stripping step processes the billet surface to remove the oxide layer present on the billet surface before extrusion; a continuous hot extrusion step extrudes the billet at a high temperature of 500℃~600℃ to a thickness of 9~15mm; a coiling step applies tension to the continuously extruded sheet while using a coiler to create coils; a cold rolling step rolls the extruded aluminum alloy to a thickness of 20~30% of the extruded sheet thickness; a stretching and straightening step passes the rolled aluminum sheet through a stretching and straightening machine to ensure the flatness of the sheet; and a cutting step cuts the flattened sheet into workable sizes.

[0053] The above melting and alloying steps involve mixing and melting the usual aluminum 5052 composition to perform alloying.

[0054] The melting and alloying step involves adding flux and stirring with nitrogen to remove hydrogen, oxides, mediators, foreign matter, etc., present in the molten metal. Hydrogen may induce bubbles on the surface of the sheet during the annealing process after extrusion and rolling, so it must be removed. Oxides, mediators, foreign matter, etc., reduce the bonding force of the billet joints (connections) during extrusion and become the initiation point of cracking during rolling, inducing the breakage of the billet joints (connections), so oxides, mediators, foreign matter, etc. must be removed.

[0055] Therefore, the above purification steps are performed, and the purification steps are followed by the following three steps to cast the billet: First purification step, the molten metal of the alloy is stirred with flux and nitrogen to remove impurities (oxides, media, foreign matter) from the molten metal; Second purification step, the molten metal purified in the first step is passed through a gas bubbling filter (GBF) while being stirred with argon to remove hydrogen and impurities from the molten metal; and Third purification step, the aluminum alloy purified in the second step is passed through a ceramic foam filter to remove impurities.

[0056] The billet casting step described above is a step of shaping the aluminum alloy melted in the melting and alloying steps into blocks of a specified size, which can be made into various sizes depending on the specifications of the final product.

[0057] The cast billet exhibits an ingot structure during solidification. Within this structure, solute atoms segregate between the grains, requiring removal. Therefore, a homogenizing heat treatment is performed at 450–600°C for 8–20 hours. The duration of this homogenizing heat treatment can be adjusted based on the billet's diameter.

[0058] Before being fed into the extruder, the billet after the above-mentioned homogenized heat treatment needs to have its surface oxide layer and anti-segregation layer peeled off. This peeling prevents oxides from flowing into the billet connection part (connection part) inside the extruder chamber. Depending on the depth of the segregation layer, the peeling amount is approximately 0.1~1mm from the surface.

[0059] The hot extrusion step described above involves heating the billet to above 500°C and applying pressure to the heated aluminum alloy billet to manufacture a sheet of a specified thickness, which is completed at high temperature.

[0060] The heat applied in the above-mentioned hot extrusion step is preferably at least 500°C or higher.

[0061] In the above hot extrusion step, if the exit temperature is below 500°C, the surface of the extruded material appears good to the naked eye. However, when extruding high-strength alloys such as 5052, the connection part of the billet may break when a tension of 1 to 3% or more is applied due to the small bonding force at the connection part. During rolling, the billet may also break due to the pressure of the rollers.

[0062] Of course, in the hot extrusion step, if the temperature reaches above 600℃, which is too high, the billet will melt, and cracks will occur at the corners during extrusion, resulting in surface oxidation and other problems. Therefore, it is necessary to control the temperature to maintain a suitable temperature for extrusion. This temperature can be controlled by confirming the preheating temperature of the billet, the extrusion speed, the extrusion pressure, and the box temperature during the extrusion process.

[0063] In existing techniques for adjusting thickness through hot rolling, when using hot-rolled sheets for cold rolling, the sheets are typically cold-rolled with a maximum thickness of 8mm. Even after cold rolling, the structure of such sheets is not dense, so they may tear during processing such as drawing when manufacturing products. However, in this invention, the thickness is increased to 10mm during hot extrusion instead of hot rolling to increase the amount of cold rolling. This results in a denser structure in the sheet after rolling. Due to the dense structure, tearing can be prevented when bending operations such as punching are performed after rolling.

[0064] In addition, in the case of hot rolling in the existing technology, there is a problem of rolling knots compared with recrystallized structure. In the case of hot extrusion, due to the fine structure recrystallized by high temperature extrusion, there are relatively fewer rolling knots compared with the case of hot rolling + cold rolling in the existing technology. Therefore, tearing or breakage can be reduced during stamping.

[0065] The above-mentioned hot extrusion step is preferably carried out at a pressure of 200 bar or more and a punch speed of 1.0 to 5.0 mm / s.

[0066] In the above-mentioned hot extrusion step, the pressure and speed are above the range mentioned above. The maximum pressure and speed can be adjusted by monitoring the state of the billet and the state of the extrusion die during the extrusion process.

[0067] By configuring the hot extrusion conditions as described above, when multiple billets are continuously hot extruded to produce long plates in the shape of discs, it is possible to prevent the connection parts (joints) between the billets from breaking or weakening.

[0068] The above-mentioned cold rolling step is a step of applying pressure to a sheet material of a specified thickness produced during hot extrusion to reduce its thickness and increase the density of the structure, rolling it to a thickness of 20 to 30% of the thickness of the sheet material produced in the above-mentioned hot extrusion step.

[0069] The above-mentioned cold rolling step can be repeated 2 to 5 times to complete the process. As mentioned above, the thickness of the sheet after the cold rolling step is 20 to 30% of the thickness of the sheet produced in the hot extrusion step.

[0070] That is, the thickness of the sheet produced in the preferred hot extrusion step is 10 mm, and the thickness of the sheet produced by the cold calendering step is preferably 4 mm.

[0071] Furthermore, it is preferable to perform stress relief and microstructure recrystallization after the above-mentioned cold rolling step, and for this purpose, it is also preferable to perform an annealing process.

[0072] In the above annealing process, the annealing conditions for aluminum 5052 sheet are 300~400℃ for 1~5 hours.

[0073] After the annealing process, a material-applying calendering process is required. This process reduces the thickness to meet the basic requirements of the calendered sheet. The material is applied by turning a 4mm thick sheet into a 3mm thick sheet. The thickness reduction rate can vary depending on the required characteristics.

[0074] The rolled sheet also needs to undergo a stabilization treatment to restore the material properties of increased strength and reduced elongation. The stabilization heat treatment is carried out at 120~180℃ for 1~5 hours. By subjecting the material to heat treatment after rolling, the basic material properties of aluminum 5052 sheet can be satisfied.

[0075] The above-mentioned stretching and straightening steps are a flattening process. When calendered coils are used for general purposes such as construction, flatness is not important, so they can be used directly. However, when used as components such as battery casings for electric vehicles, flatness is very important, and it is necessary to ensure flatness in all directions. The flattening process is the step that ensures flatness.

[0076] The above-mentioned winding step is the process of winding the aluminum sheet into a coil shape, which is usually carried out by a winding device for winding aluminum coils.

[0077] However, during the process of winding wide aluminum coils, the coils cannot be wound neatly onto the winding rollers, and the two ends of the wound coils may become irregular. In the process of manufacturing products such as battery casings or cans, it is necessary to cut off the irregular parts of the coils wound at the irregular ends, which may result in material waste.

[0078] Therefore, as Figure 3 As shown, the winding device preferably includes: a plurality of conveying rollers 10 for conveying the extruded aluminum alloy sheet; a pressing roller 20, which is arranged at the rear end of the conveying table to press the sheet to apply tension to the sheet conveyed by the conveying rollers; a winding machine 30, which has a winding drum 32 driven to rotate by a drive mechanism 31, onto which the sheet is wound; and a guiding mechanism 40 for guiding the sheet to be wound neatly without detaching from the end of the winding drum.

[0079] like Figure 3 As shown, the plurality of the aforementioned conveying rollers 10 are arranged at equal intervals to support the smooth movement of the rolled or extruded aluminum sheet without resistance.

[0080] A portion of the aforementioned conveyor rollers 10 are arranged parallel to the adjacent conveyor rollers 10. However, the conveyor rollers 10 located in the adjacent portion of the winding machine are arranged along an inclined surface so that they gradually increase in height toward the winding machine. As a result, the sheet material conveyed to the winding machine is subjected to a force in the opposite direction to the winding machine, and remains taut when wound by the winding machine, enabling uniform winding.

[0081] Of course, as shown in the figure, the several conveyor rollers close to the coiler are kept horizontal to ensure a stable supply of aluminum sheet to the coiler.

[0082] like Figure 1 As shown, the aforementioned pressing roller 20 is disposed at the front end of the winding machine, and serves to press the upper surface of the sheet material so that the sheet material moving along the upper part of the aforementioned conveying roller is supplied in a state of being tightly attached to the winding drum of the winding machine. The pressing roller can also be disposed facing upward or downward.

[0083] The aforementioned coiler 30 is a device for coiling aluminum sheets into a coil shape. Similar to a conventional coiler, it includes a coil drum 32 that is rotated by a drive mechanism 31.

[0084] A guide mechanism 40 is also provided on one side. To fix one end of the aluminum sheet, at least one groove 32g is formed on the winding drum 32 along the width direction of the sheet. That is, the aluminum sheet winding device of the present invention is a device for winding aluminum sheets with a thickness of 3 to 10 mm into a coil shape. It does not require a winding roller for winding wire or film. As long as the sheet is wound into a coil shape on the winding drum, the coil shape can be maintained even when the wound sheet is separated from the winding drum. Therefore, it is necessary to fix one end of the sheet to the winding drum, and the above-mentioned groove is formed for this purpose. Of course, the groove can also have the function of narrowing when separating the wound coil from the winding drum, making it easier to separate the wound coil from the winding drum.

[0085] The aforementioned guiding mechanism 40 is used to guide the coiled aluminum sheet to a certain part of the winding drum, and includes: a push roller 41, which is disposed at the other end of a rotating roller that is rotatable at one end, and presses the sheet being fed to the upper part of the winding drum toward the winding drum; guide plates 42, which are respectively disposed at both ends of the push roller, and guide the two sides of the sheet to be wound onto the winding drum without detaching from the winding drum; and a rotating mechanism 43, which rotates the rotating roller to press the push roller toward the winding drum.

[0086] As described above, the guide mechanism 40 causes the push roller to press the sheet material wound onto the winding drum so that the wound sheet material is kept in close contact with the already wound sheet material. The guide plates provided at both ends of the push roller guide the portion of the sheet material being wound so that the two ends of the sheet material are wound in a state where they do not detach from the ends of the already wound sheet material.

[0087] Furthermore, the winding device of the present invention also includes a coil discharge mechanism 50 at the lower part of the winding cylinder.

[0088] The aforementioned coil discharge mechanism 50 is a mechanism for separating and discharging the sheet metal coil wound onto the winding drum from the winding machine. It includes: a coil trolley 51 for supporting the sheet metal coil separated from the winding drum; a guide rail 52 for guiding the movement of the coil trolley; and a drive mechanism 53 for moving the coil trolley along the guide rail.

[0089] Furthermore, compared to existing methods that construct large underground ingot pits due to differences in winding speed and exit speed, this invention uses an encoder to unify the winding speed of the coiler and the exit speed of the extruder, thereby eliminating the ingot pit and improving space efficiency.

Claims

1. A method for manufacturing 5052 aluminum sheet using extrusion and rolling, for producing 5052 aluminum alloy sheet as raw material for battery cans or casings. Its features are, The process includes: a melting and alloying step, melting the 5052 aluminum components to form an alloy; a purification step, removing foreign matter to control the purity of the molten metal; a billet casting step, manufacturing billets to a specified width, thickness, and length; a stripping step, removing oxides, foreign matter, and anti-segregation layers from the billet surface; a hot extrusion step, extruding the billet at a high temperature above 500°C to a thickness of 9-15 mm; a coiling step, coiling the hot-extruded sheet to manufacture coils; a cold rolling step, rolling the extruded aluminum alloy to a thickness of 20-30% of the extruded sheet thickness; a stretching and straightening step, ensuring the flatness of the rolled aluminum coils through stretching and straightening; and a cutting step, cutting the rolled aluminum coils after stretching and straightening for manufacturing the battery casing. The cold-rolled aluminum sheets also undergo the following steps: an annealing step, performed at 300-400℃ for 1-5 hours, to relieve stress and recrystallize the microstructure; and a stabilization step, performed at 130-180℃ for 1-5 hours, to restore the material properties that resulted in increased strength and decreased elongation during the cold rolling process. The cast billets were subjected to homogenization heat treatment at 450-600℃ for 8-20 hours to remove segregation formed by intergranular solute atoms in the ingot structure generated during the solidification process. In the above-described stripping step, the stripping amount performed is 0.1~1 mm from the surface, depending on the depth of the segregated layer. In the hot extrusion step, the hot extrusion thickness is made to 10mm to increase the cold rolling amount in the cold rolling step, thereby making the microstructure of the rolled sheet more dense. This dense microstructure prevents tearing during the bending operation by punching after rolling. The above cold rolling process is completed by repeating the rolling process 2 to 5 times. The thickness of the sheet material rolled through the cold rolling process is 4 mm. After the above annealing process, a material-applying calendering step is performed, which calenders the 4mm thick sheet to 3mm.

2. The method for manufacturing 5052 aluminum sheet by extrusion and rolling as described in claim 1, characterized in that, The above purification steps include: The first purification step involves stirring the alloyed molten metal with flux and nitrogen to remove impurities from the molten metal, including oxides, media, and foreign matter. The second purification step involves passing the molten metal purified in the first step through a gas bubble filter while simultaneously stirring it with argon gas to remove hydrogen and impurities from the molten metal; and The third purification step involves passing the aluminum alloy purified in the second step through a ceramic foam filter to remove impurities.

3. The method for manufacturing 5052 aluminum sheet by extrusion and rolling as described in claim 1 or 2, characterized in that, Also includes: The above-mentioned hot extrusion step is carried out under a pressure of more than 200 bar, at a speed of 1.0~5.0 mm / s, and at a temperature range of 500~600℃.

4. The method for manufacturing 5052 aluminum sheet by extrusion and rolling as described in claim 1 or 2, characterized in that, The above-mentioned winding step is performed by the winding device. The above-mentioned winding device includes: Multiple conveyor rollers (10) are used to convey the extruded aluminum alloy sheet; The pressing roller (20) presses the sheet material conveyed by the above-mentioned conveying roller toward the coiler side; The winding machine (30) includes a winding drum (32) driven to rotate by a drive mechanism (31), onto which sheet metal is wound; and The guiding mechanism (40) guides the sheet material to be neatly wound without detaching from the end of the winding drum.

5. The method for manufacturing 5052 aluminum sheet by extrusion and rolling as described in claim 3, characterized in that, The above-mentioned winding step is performed by the winding device. The above-mentioned winding device includes: Multiple conveyor rollers (10) are used to convey the extruded aluminum alloy sheet; The pressing roller (20) presses the sheet material conveyed by the above-mentioned conveying roller toward the coiler side; The winding machine (30) includes a winding drum (32) driven to rotate by a drive mechanism (31), onto which sheet metal is wound; and The guiding mechanism (40) guides the sheet material to be neatly wound without detaching from the end of the winding drum.

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