Device and method for suppressing edge cracking during rolling of magnesium alloy sheet and strip using symmetrically arranged rolls

Abstract

This invention relates to an apparatus and method for suppressing edge cracking during the rolling of magnesium alloy sheet and strip using symmetrically arranged rolls, belonging to the technical field of magnesium alloy sheet and strip rolling forming. The apparatus of this invention includes two pairs of rolls, an external frame, and a control console. It has the advantages of optimized structure, simple parts, simple manufacturing process, and low manufacturing cost. Simultaneously, it can reduce energy consumption in magnesium alloy sheet and strip rolling technology, improve production efficiency, suppress edge cracking, improve room temperature forming performance of rolled magnesium alloy sheet and strip, and expand the application range of magnesium alloys. Furthermore, this invention also discloses a method for suppressing edge cracking during the rolling of magnesium alloy sheet and strip using symmetrically arranged rolls. The required temperature during the rolling process is lower than that of traditional rolling processes, significantly reducing production energy consumption, saving production costs, improving production efficiency, suppressing edge cracking, and resulting in magnesium alloy sheet and strip with superior room temperature forming properties.

Description

Technical Field

[0001] This invention belongs to the technical field of magnesium alloy sheet and strip rolling forming, and relates to a device and method for suppressing edge cracking of magnesium alloy sheet and strip during rolling by symmetrically arranged rolls. Background Technology

[0002] Magnesium alloys are the least dense metallic structural materials, possessing advantages such as high specific strength and specific stiffness, non-sparking during friction, and easy recyclability. Therefore, they are hailed as "green energy materials of the 21st century" and are widely used in automotive, 3C, aerospace, and military fields. However, due to their close-packed hexagonal crystal structure, magnesium alloys cannot meet the Von-Mises criterion for plastic deformation at room temperature, resulting in poor room-temperature forming performance. This limits the efficient production of magnesium alloy sheets and strips and their applications in various fields. Most notably, magnesium alloy sheets and strips produced by traditional rolling methods often exhibit severe edge cracking, requiring trimming after rolling and resulting in significant material waste. Furthermore, especially under high rolling pressure, the resulting magnesium alloy sheets and strips may even shatter directly. To improve edge cracking during rolling, increasing the rolling temperature is often used; however, this increases energy consumption and production costs.

[0003] Therefore, the invention of a device and method that is simple in structure and can effectively suppress edge cracking during the rolling of magnesium alloy plates and strips is a problem that urgently needs to be solved. Summary of the Invention

[0004] In view of this, one objective of the present invention is to provide an apparatus for suppressing edge cracking of magnesium alloy sheet and strip during rolling with symmetrically arranged rolls; a second objective of the present invention is to provide an installation method for the apparatus for suppressing edge cracking of magnesium alloy sheet and strip during rolling with symmetrically arranged rolls; and a third objective of the present invention is to provide a rolling method for suppressing edge cracking of magnesium alloy sheet and strip during rolling with symmetrically arranged rolls.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] 1. A device for suppressing edge cracking during the rolling of magnesium alloy sheet and strip using symmetrically arranged rolls, the device comprising two pairs of rolls, an external frame, and a control console;

[0007] The two pairs of rolls include a left roll pair formed by an upper roll 17-1 located to the left of the upper universal joint 15-2 and a lower roll 17-2 located to the left of the lower universal joint 15-1, and a right roll pair formed by an upper roll 17-1 located to the right of the upper universal joint 15-2 and a lower roll 17-2 located to the right of the lower universal joint 15-1. In the left roll pair, the axes of the upper roll 17-1 and the lower roll 17-2 are parallel; in the right roll pair, the axes of the upper roll 17-1 and the lower roll 17-2 are parallel. The distance between the upper roll 17-1 and the lower roll 17-2 in each roll pair is equal to the thickness of the magnesium alloy slab 14 to be processed. The lower roll 17-2 passes through the lower bearing seat 25-2, the lower bearing cover 26-2, and the center lower... Bearing housing 12-2 and center lower bearing cover 13-2 are fixed to the outer frame. Upper roll 17-1 is fixed to movable crossbeam 11 via upper bearing housing 25-1, upper bearing cover 26-1, center upper bearing housing 12-1 and center upper bearing cover 13-1 to adjust the gap between upper and lower rolls. Two pairs of rolls are symmetrically arranged in the outer frame, and the power of the two pairs of rolls comes from a single electric motor. Mechanical transmission is achieved between the two upper rolls 17-1 and between the two lower rolls 17-2 through universal joints. The upper universal joint 15-2 is arranged between the center upper bearing housing 12-1 and the center upper bearing cover 13-1, and the lower universal joint 15-1 is arranged between the center lower bearing housing 12-2 and the center lower bearing cover 13-2.

[0008] The external frame includes a base 18, a column 27, a base connecting bolt 19, two lower bearing seats 25-2, two lower bearing covers 26-2, a lower bearing fastening bolt 16-1, a central lower bearing seat 12-2, a central lower bearing cover 13-2, a central bearing fastening bolt 28, a central upper bearing seat 12-1, a central upper bearing cover 13-1, a movable crossbeam 11, a transmission load-bearing screw 10, an upper seat 24, an upper seat connecting bolt 23, two upper bearing covers 26-1, two upper bearing seats 25-1, and an upper bearing fastening bolt. 16-2, center gear 8-3, left gear 8-1, right gear 8-2, transmission key 9, gear cover 22, center gear shaft 21, rotating wheel 7, base 18 and column 27 are fixed by base connecting bolt 19, lower bearing seat 25-2 and lower bearing cover 26-2 are connected and fixed to base 18 by lower bearing fastening bolt 16-1, and are symmetrically arranged on the left and right sides of base 18, and center lower bearing seat 12-2 and center lower bearing cover 13-2 are connected and fixed to base 1 by center bearing fastening bolt 28. 8. The upper bearing seat 25-1 and the upper bearing cover 26-1 are connected and fixed to the movable crossbeam 11 by the upper bearing fastening bolt 16-2, and are symmetrically arranged on the left and right sides of the movable crossbeam 11. The central upper bearing seat 12-1 and the central upper bearing cover 13-1 are connected and fixed to the movable crossbeam 11 by the central bearing fastening bolt 28, and are arranged in the middle of the movable crossbeam 11. The upper seat 24 is connected to the column 27 by the upper seat connecting bolt 23. The transmission bearing screw 10 is connected to the movable crossbeam 11. The gear is connected to the T-slot and threaded to the upper seat 24. It meshes and drives with the left gear 8-1 and the right gear 8-2 through the transmission key 9. The left gear 8-1 and the right gear 8-2 are respectively arranged to the left and right of the center gear 8-3 and are connected to the center gear 8-3 for transmission. The center gear shaft 21 is connected to the center gear 8-3 for transmission and is connected to the rotating wheel 7. The gear cover 22 is connected to the upper seat 24, covering and restricting the up and down movement of the left gear 8-1, the right gear 8-2 and the center gear 8-3.

[0009] The control console is connected to the outer frame and two pairs of rollers via wires 20. The control console consists of an electronic display screen 1, a start button 3, a stop button 4, an emergency brake button 2, a parameter setting panel 5, a control console body 6, and wires 20.

[0010] Preferably, the included angle between the axes of the two upper rolls 17-1 and the included angle between the axes of the two lower rolls 17-2 are both α, where 0°<α≤30°;

[0011] When the device is in operation, the angle between the rolling direction of the magnesium alloy strip and the rotational linear velocity direction of the two pairs of rolls is α / 2.

[0012] 2. The installation method of the above-mentioned device is as follows:

[0013] Secure the column 27 to the corresponding position on the base 18 using the base connecting bolts 19; symmetrically arrange the lower bearing housing 25-2 on the left and right sides of the base 18 and secure it with bolts; arrange the central lower bearing housing 12-2 in the middle of the base 18 and secure it with bolts; place the lower roller 17-2 of the two pairs of rollers inside the lower bearing housing 25-2 and the central lower bearing housing 12-2 and apply graphite oil solution for lubrication, and connect them with the lower universal joint 15-1; secure the lower bearing cover 26-2 to the lower bearing housing 25-2 using the lower bearing fastening bolts 16-1, and simultaneously secure the central lower bearing cover 13-2 to the central lower bearing housing 12-2 using the central bearing fastening bolts 28; and install the upper bearing... Seat 25-1 is symmetrically arranged on the left and right sides of the movable crossbeam 11 and fastened with bolts. The central upper bearing seat 12-1 is arranged in the middle of the movable crossbeam 11 and fastened with bolts. The upper roll 17-1 of the two pairs of rolls is arranged in the upper bearing seat 25-1 and the central upper bearing seat 12-1 and lubricated with graphite oil solution, and connected with the upper universal joint 15-2. The upper bearing cover 26-1 is fastened to the upper bearing seat 25-1 with the upper bearing fastening bolt 16-2, and the central upper bearing cover 13-1 is fastened to the central upper bearing seat 12-1 with the central bearing fastening bolt 28. The transmission bearing screw 10 is screwed into the corresponding threaded hole of the upper seat 24 and the two transmission bearing screws 10 are kept in the same position. With the same input, the left gear 8-1 and right gear 8-2 are connected to the corresponding transmission bearing screws 10 via transmission keys 9; the central gear shaft 21 is connected to the central gear 8-3 via transmission keys 9, and the central gear shaft 21 is arranged in the corresponding hole of the upper seat 24. The central gear 8-3 is arranged between the left gear 8-1 and the right gear 8-2 to achieve gear meshing transmission; the gear cover 22 is installed in the corresponding position of the upper seat 24 to limit the left gear 8-1, right gear 8-2 and the middle gear 8-3; the transmission bearing screw 10 is installed in the T-slot corresponding to the movable crossbeam 11 to realize the connection between the upper roll 17-1 of the two pairs of rolls, the movable crossbeam 11, and the transmission bearing screw. 10. The upper seat 24, left gear 8-1, right gear 8-2, and center gear 8-3 are combined; the movable crossbeam 11 is installed in the space surrounded by the column 27 to achieve a clearance fit between the movable crossbeam 11 and the column 27. At the same time, the upper seat 24 is installed and fastened to the corresponding position of the column 27 through the upper seat connecting bolt 23 to complete the overall assembly of the device; the rotating wheel 7 is installed on the center gear shaft 21 to achieve the connection and transmission of the rotating wheel 7, center gear 8-3, left gear 8-1, right gear 8-2, transmission bearing screw 10, and movable crossbeam 11. Finally, the height of the movable crossbeam 11 is adjusted by rotating the rotating wheel 7 to control the gap between the upper and lower rollers to be equal to the required thickness of the magnesium alloy strip.

[0014] Preferably, before installation, the device for suppressing edge cracking of magnesium alloy strip during rolling with symmetrically arranged rolls is coated with graphite oil solution to increase lubricity on the outer surfaces of the two pairs of rolls, the outer surface of the left gear 8-1, the outer surface of the center gear 8-3, the outer surface of the right gear 8-2, the outer surface of the transmission bearing screw 10, and the contact surface between the movable crossbeam 11 and the column 27.

[0015] 3. A rolling method for suppressing edge cracking in magnesium alloy sheet and strip by symmetrically arranged rolls, the rolling method being as follows:

[0016] (1) The pretreated magnesium alloy slab 14 is placed in an electric heating furnace at a temperature of 100-300℃ and kept at that temperature for 0.5h-1h to obtain a preheated magnesium alloy slab 14.

[0017] (2) The temperature of the rolls in the above-mentioned symmetrically arranged rolls to suppress edge cracks in the rolling of magnesium alloy strip is set in the range of room temperature to 250°C and kept in a preheated state.

[0018] (3) Take the preheated magnesium alloy slab 14 out of the electric heating furnace and send it into the preheated device from the feeding side. Start the device to make the magnesium alloy slab 14 undergo a symmetrical rolling process. After cleaning with acetone and anhydrous ethanol in sequence, blow dry with a hair dryer or air dry naturally before use.

[0019] Preferably, the specific method of the preprocessing is as follows:

[0020] (1) Use 600-grit sandpaper to polish the surface of the magnesium alloy slab 14 to be treated to remove oil stains, and then use 800-grit, 1000-grit and 1200-grit sandpaper in sequence to polish to ensure that the surface of the magnesium alloy slab 14 to be treated is smooth.

[0021] (2) Wipe and clean with acetone, then dry with a hair dryer;

[0022] (3) Next, wipe and clean with anhydrous ethanol and then dry with a hair dryer;

[0023] (4) Apply graphite oil solution to the surface of magnesium alloy slab 14 to obtain pretreated magnesium alloy slab 14.

[0024] Preferably, during the rolling process, if a magnesium alloy sheet or strip with the target thickness cannot be obtained by single-pass symmetrical rolling, the magnesium alloy sheet or strip obtained in the previous pass is reheated to 100-300°C and held for 10-30 minutes, and then symmetrical rolling is performed again and the above process is repeated to obtain a magnesium alloy sheet or strip with the required thickness.

[0025] The beneficial effects of this invention are as follows:

[0026] 1. This invention discloses a device for suppressing edge cracking during the rolling of magnesium alloy sheet and strip using symmetrically arranged rolls. The device includes two pairs of rolls, an external frame, and a control console. It has the advantages of optimized structure, simple parts, simple manufacturing process, and low manufacturing cost. At the same time, it can reduce the energy consumption of magnesium alloy sheet and strip rolling technology, improve the production efficiency of rolled magnesium alloy sheet and strip, suppress edge cracking during the rolling of magnesium alloy sheet and strip, improve the room temperature forming performance of rolled magnesium alloy sheet and strip, and expand the application range of magnesium alloy.

[0027] 2. The present invention also discloses a method for suppressing edge cracking of magnesium alloy sheet and strip during rolling by symmetrically arranged rolls. The rolling process requires a lower temperature than the traditional rolling process, which significantly reduces production energy consumption, saves production costs, and improves production efficiency. The edge cracking phenomenon of the rolled magnesium alloy sheet and strip is weakened, and it has better room temperature formability.

[0028] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0030] Figure 1 This is a schematic diagram of the symmetrically arranged rolls of the present invention;

[0031] Figure 2 This is a schematic diagram of the device for suppressing edge cracking during the rolling of magnesium alloy sheet and strip using symmetrically arranged rolls according to the present invention.

[0032] Figure 3 This is a schematic diagram showing the connection between the transmission load-bearing screw 10 and the parts in contact with it.

[0033] Figure 4 This is a schematic diagram of the rolling direction-transverse plane force on magnesium alloy sheet / strip during rolling processing using the symmetrical arrangement device of the present invention.

[0034] Among them, 1 is the electronic display screen, 2 is the emergency brake button, 3 is the start button, 4 is the stop button, 5 is the parameter setting panel, 6 is the control panel, 7 is the rotary wheel, 8-1 is the left gear, 8-2 is the right gear, 8-3 is the center gear, 9 is the transmission key, 10 is the transmission bearing screw, 11 is the movable crossbeam, 12-1 is the upper center bearing seat, 12-2 is the lower center bearing seat, 13-1 is the upper center bearing cover, 13-2 is the lower center bearing cover, 14 is the magnesium alloy slab, and 15-1 is the lower... Universal joint, 15-2 is upper universal joint, 16-1 is lower bearing fastening bolt, 16-2 is upper bearing fastening bolt, 17-1 is upper roller, 17-2 is lower roller, 18 is base, 19 is base connecting bolt, 20 is wire, 21 is center gear shaft, 22 is gear cover, 23 is upper seat connecting bolt, 24 is upper seat, 25-1 is upper bearing seat, 25-2 is lower bearing seat, 26-1 is upper bearing cover, 26-2 is lower bearing cover, 27 is column, 28 is center bearing fastening bolt;

[0035] Figure 5 The results of the forming performance test of the magnesium alloy sheet obtained in the example are shown.

[0036] Figure 6 The forming performance test results of magnesium alloy sheets obtained by processing the same magnesium alloy slab using traditional rolling equipment and methods.

[0037] Figure 7 This is the (0001) pole figure of the magnesium alloy sheet obtained in the example;

[0038] Figure 8 The (0001) pole figure is a magnesium alloy sheet obtained by processing the same magnesium alloy slab using conventional rolling equipment and methods. Detailed Implementation

[0039] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0040] Example

[0041] 1. A device for suppressing edge cracking of magnesium alloy sheet and strip during rolling with symmetrically arranged rolls, comprising two pairs of rolls, an external frame and a control console (the control console is connected to the external frame and the two pairs of rolls via wires 20 to control the operation of the entire device, and the control console consists of an electronic display screen 1, a start button 3, a stop button 4, an emergency brake button 2, a parameter setting panel 5, a control console body 6 and wires 20);

[0042] The two pairs of rolls include a left roll pair formed by an upper roll 17-1 located to the left of the upper universal joint 15-2 and a lower roll 17-2 located to the left of the lower universal joint 15-1, and a right roll pair formed by an upper roll 17-1 located to the right of the upper universal joint 15-2 and a lower roll 17-2 located to the right of the lower universal joint 15-1. The axes of the upper roll 17-1 and lower roll 17-2 in the left roll pair are parallel, and the axes of the upper roll 17-1 and lower roll 17-2 in the right roll pair are parallel. The distance between the upper roll 17-1 and lower roll 17-2 is the thickness of the magnesium alloy slab 14 to be processed. The lower roll 17-2 passes through a lower bearing seat 25-2, a lower bearing cover 26-2, and a central lower bearing seat 1. 2-2 and the lower central bearing cover 13-2 are fixed to the outer frame. The upper roller 17-1 is fixed to the movable crossbeam 11 through the upper bearing seat 25-1, the upper bearing cover 26-1, the upper central bearing seat 12-1, and the upper central bearing cover 13-1 to adjust the gap between the upper and lower rollers. The two pairs of rollers are symmetrically arranged in the outer frame, and the power of the two pairs of rollers comes from a single electric motor. The two upper rollers 17-1 and the two lower rollers 17-2 are connected by universal joints to realize mechanical transmission. The upper universal joint 15-2 is arranged between the upper central bearing seat 12-1 and the upper central bearing cover 13-1, and the lower universal joint 15-1 is arranged between the lower central bearing seat 12-2 and the lower central bearing cover 13-2. In addition, the axes of the upper roll 17-1 and the lower roll 17-2 of each pair of rolls are parallel, and there is an included angle α between the axes of the upper roll 17-1 and the lower roll 17-2 of the two pairs of rolls (the value is 30° in this embodiment). When the device is working, the included angle between the rolling direction of the magnesium alloy strip and the rotational linear velocity direction of the two pairs of rolls is α / 2 (the value is 15° in this embodiment).

[0043] The aforementioned external frame includes a base 18, a column 27, a base connecting bolt 19, two lower bearing seats 25-2, two lower bearing covers 26-2, a lower bearing fastening bolt 16-1, a central lower bearing seat 12-2, a central lower bearing cover 13-2, a central bearing fastening bolt 28, a central upper bearing seat 12-1, a central upper bearing cover 13-1, a movable crossbeam 11, a transmission load-bearing screw 10, an upper seat 24, an upper seat connecting bolt 23, two upper bearing covers 26-1, two upper bearing seats 25-1, and upper bearing fastening bolts. 16-2, center gear 8-3, left gear 8-1, right gear 8-2, transmission key 9, gear cover 22, center gear shaft 21, rotating wheel 7, base 18 and column 27 are fixed by base connecting bolt 19, lower bearing seat 25-2 and lower bearing cover 26-2 are connected and fixed to base 18 by lower bearing fastening bolt 16-1, and are symmetrically arranged on the left and right sides of base 18, and center lower bearing seat 12-2 and center lower bearing cover 13-2 are connected and fixed to base 1 by center bearing fastening bolt 28. 8. The upper bearing seat 25-1 and the upper bearing cover 26-1 are connected and fixed to the movable crossbeam 11 by the upper bearing fastening bolt 16-2, and are symmetrically arranged on the left and right sides of the movable crossbeam 11. The central upper bearing seat 12-1 and the central upper bearing cover 13-1 are connected and fixed to the movable crossbeam 11 by the central bearing fastening bolt 28, and are arranged in the middle of the movable crossbeam 11. The upper seat 24 is connected to the column 27 by the upper seat connecting bolt 23. The transmission bearing screw 10 is connected to the movable crossbeam 11. The gear is connected to the T-slot and threaded to the upper seat 24. It meshes and drives with the left gear 8-1 and the right gear 8-2 via the transmission key 9. The left gear 8-1 and the right gear 8-2 are respectively arranged to the left and right of the center gear 8-3 and are connected to the center gear 8-3 for transmission. The center gear shaft 21 is connected to the center gear 8-3 for transmission and is connected to the rotating wheel 7. The gear cover 22 is connected to the upper seat 24, covering and restricting the up and down movement of the left gear 8-1, the right gear 8-2 and the center gear 8-3.

[0044] Figure 1 A schematic diagram of the symmetrically arranged rolls of the present invention is shown below. Figure 1 As shown, Figure 2 A schematic diagram of a device for suppressing edge cracks in magnesium alloy sheet and strip rolling with symmetrically arranged rolls is shown. A connection diagram of the drive-bearing screw 10 and its contacting parts is also shown. Figure 3 As shown, the schematic diagram of the forces acting on the magnesium alloy strip in the rolling direction and transverse plane during rolling processing using the symmetrical arrangement device of the present invention is as follows. Figure 4 As shown.

[0045] The installation method of the above device is as follows:

[0046] First, before the installation of the device for suppressing edge cracks in the rolling of magnesium alloy strip and sheet, a graphite oil solution is applied to the outer surfaces of the two pairs of rolls, the outer surface of the left gear 8-1, the outer surface of the center gear 8-3, the outer surface of the right gear 8-2, the outer surface of the transmission bearing screw 10, and the contact surface between the movable crossbeam 11 and the column 27 to increase lubrication.

[0047] Next, the column 27 is fastened to the corresponding position on the base 18 using the base connecting bolts 19; the lower bearing housing 25-2 is symmetrically arranged on the left and right sides of the base 18 and fastened with bolts, and the central lower bearing housing 12-2 is arranged in the middle of the base 18 and fastened with bolts; the lower roller 17-2 of the two pairs of rollers is arranged in the lower bearing housing 25-2 and the central lower bearing housing 12-2 and coated with graphite oil solution for lubrication, and connected with the lower universal joint 15-1; the lower bearing cover 26-2 is fastened to the lower bearing housing 25-2 using the lower bearing fastening bolts 16-1, and the central lower bearing cover 13-2 is fastened to the central lower bearing housing 12-2 using the central bearing fastening bolts 28; the upper... Bearing housings 25-1 are symmetrically arranged on the left and right sides of the movable crossbeam 11 and fastened with bolts. The central upper bearing housing 12-1 is arranged in the middle of the movable crossbeam 11 and fastened with bolts. The upper roll 17-1 of the two pairs of rolls is placed inside the upper bearing housing 25-1 and the central upper bearing housing 12-1 and lubricated with graphite oil solution, while connected using the upper universal joint 15-2. The upper bearing cover 26-1 is fastened to the upper bearing housing 25-1 using the upper bearing fastening bolt 16-2, while the central upper bearing cover 13-1 is fastened to the central upper bearing housing 12-1 using the central bearing fastening bolt 28. The transmission bearing screw 10 is screwed into the corresponding threaded hole of the upper seat 24 and the two transmission bearing screws 10 are held in place. With the same screw-in amount, the left gear 8-1 and right gear 8-2 are connected to the corresponding transmission bearing screws 10 via transmission keys 9; the central gear shaft 21 is connected to the central gear 8-3 via transmission keys 9, and the central gear shaft 21 is arranged in the corresponding hole of the upper seat 24. The central gear 8-3 is arranged between the left gear 8-1 and the right gear 8-2 to achieve gear meshing transmission; the gear cover 22 is installed in the corresponding position of the upper seat 24 to limit the left gear 8-1, right gear 8-2 and the middle gear 8-3; the transmission bearing screw 10 is installed in the T-slot corresponding to the movable crossbeam 11 to realize the connection between the upper roll 17-1 of the two pairs of rolls, the movable crossbeam 11, and the transmission bearing screw. The rod 10, upper seat 24, left gear 8-1, right gear 8-2, and center gear 8-3 are combined; the movable crossbeam 11 is installed in the space surrounded by the column 27 to achieve a clearance fit between the movable crossbeam 11 and the column 27. At the same time, the upper seat 24 is installed and fastened to the corresponding position of the column 27 through the upper seat connecting bolt 23 to complete the overall assembly of the device; the rotating wheel 7 is installed on the center gear shaft 21 to achieve the connection and transmission of the rotating wheel 7, center gear 8-3, left gear 8-1, right gear 8-2, transmission bearing screw 10, and movable crossbeam 11. Finally, the height of the movable crossbeam 11 is adjusted by rotating the rotating wheel 7 to control the gap between the upper and lower rollers to be equal to the required thickness of the magnesium alloy strip.

[0048] II. A method for rolling magnesium alloy sheets, as detailed below:

[0049] 1. Selected materials, hardware tools, and chemical reagents: Magnesium alloy slab 14, rectangular slab, grade AZ31, containing 96% magnesium, 3% aluminum, and 1% zinc, with a thickness of 10mm; sandpaper, solid; anhydrous ethanol, liquid, analytical grade; acetone, liquid, analytical grade; graphite oil solution, suspension.

[0050] 2. Pre-treatment of magnesium alloy slab 14: (1) Polish the surface of the magnesium alloy slab 14 to be treated with 600 grit sandpaper to remove oil stains, and then polish with 800 grit, 1000 grit and 1200 grit sandpaper in sequence to ensure that the surface of the magnesium alloy slab 14 to be treated is smooth.

[0051] (2) Wipe and clean with acetone, then dry with a hair dryer;

[0052] (3) Next, wipe and clean with anhydrous ethanol and then dry with a hair dryer;

[0053] (4) Apply graphite oil solution to the surface of magnesium alloy slab 14 to obtain pretreated magnesium alloy slab 14.

[0054] 3. The pretreated magnesium alloy slab 14 is placed in an electric heating furnace at a temperature of 200℃ and kept at that temperature for 1 hour to obtain the preheated magnesium alloy slab 14.

[0055] 4. Set the temperature of the rolls in the above-mentioned symmetrically arranged rolls to 100°C and keep them in a preheated state.

[0056] 5. Take the preheated magnesium alloy slab 14 out of the electric heating furnace and send it into the preheated device from the feed side. Start the device to make the magnesium alloy slab 14 undergo a symmetrical rolling process. If a magnesium alloy strip with a thickness of 2 mm cannot be obtained by a single pass of symmetrical rolling, the magnesium alloy strip obtained in the previous pass is reheated to 200°C and held for 10 minutes. Then, symmetrical rolling is performed again and the above process is repeated to obtain a magnesium alloy strip with a thickness of 2 mm.

[0057] 6. The magnesium alloy sheet and strip obtained in the above process are cleaned with acetone and anhydrous ethanol in sequence and then air-dried before being put into use.

[0058] Performance testing

[0059] The forming performance test results of the magnesium alloy sheet obtained in the examples are as follows: Figure 5 As shown, the test results of the forming properties of magnesium alloy sheets obtained after processing the same magnesium alloy slab using conventional rolling equipment and methods are as follows: Figure 6 As shown. Comparison Figure 5 and Figure 6It can be seen that the forming performance of AZ31 magnesium alloy sheet obtained by using the device and method of the present invention is significantly better than that of AZ31 magnesium alloy sheet obtained by using the traditional rolling method, with forming performances of 4.87 mm and 3.08 mm, respectively.

[0060] The (0001) pole figure of the magnesium alloy sheet obtained in the embodiment is as follows: Figure 7 As shown, the (0001) pole figure of the magnesium alloy sheet obtained after processing the same magnesium alloy slab using conventional rolling equipment and methods is as follows. Figure 8 As shown. Comparison Figure 7 and Figure 8 It can be seen that the (0001) base texture of the AZ31 magnesium alloy sheet obtained by using the device and method of the present invention is significantly weaker than that of the AZ31 magnesium alloy sheet obtained by using the conventional rolling method, that is, it is weakened from 19.08 to 7.85.

[0061] The following description, in conjunction with the accompanying drawings and specific embodiments, explains the principle of the symmetrically arranged rolls for suppressing edge cracks in magnesium alloy sheet and strip during rolling, including the device and processing method for suppressing edge cracks in magnesium alloy sheet and strip during rolling:

[0062] When performing symmetrical rolling using the apparatus of the present invention, for the left half of the magnesium alloy slab 14, the frictional force generated by the rolls (17-1, 17-2) on the magnesium alloy slab 14 is along the linear velocity direction (tangential) of the rolls (17-1, 17-2), and the rolling direction is at 15° with the tangential direction. Therefore, the tangential force can be decomposed into a force along the transverse rolling direction and a force along the rolling direction, and the transverse component is directed to the right. Similarly, for the right half of the magnesium alloy slab 14, the frictional force generated by the rolls (17-1, 17-2) on the magnesium alloy slab 14 is also along the tangential direction, and can be similarly decomposed into a force along the transverse rolling direction and a force along the rolling direction, and the transverse force is directed to the left. Therefore, for the magnesium alloy slab 14, its left half is subjected to a lateral force to the right and its right half is subjected to a lateral force to the left. Thus, lateral compressive stress exists inside the magnesium alloy slab 14, which improves its rolling forming capability. It is evident that using the symmetrically arranged rolls of this invention to suppress edge cracking in magnesium alloy strip during rolling can indeed produce rolled magnesium alloy strip with high room temperature forming performance.

[0063] In summary, this invention discloses a device for suppressing edge cracking during the rolling of magnesium alloy sheet and strip using symmetrically arranged rolls. This device comprises two pairs of rolls, an external frame, and a control console. It offers advantages such as optimized structure, simple parts, simple manufacturing process, and low manufacturing cost. Simultaneously, it reduces energy consumption in magnesium alloy sheet and strip rolling technology, improves production efficiency, enhances room temperature formability of rolled magnesium alloy sheet and strip, and expands the application range of magnesium alloys. Furthermore, this invention also discloses a method for suppressing edge cracking during the rolling of magnesium alloy sheet and strip using symmetrically arranged rolls. The required rolling temperature is lower than that of traditional rolling processes, significantly reducing production energy consumption, saving production costs, improving production efficiency, suppressing edge cracking during the rolling of magnesium alloy sheet and strip, and resulting in magnesium alloy sheet and strip with superior room temperature formability.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A device for suppressing edge cracking during rolling of magnesium alloy sheet and strip using symmetrically arranged rolls, characterized in that, The device includes two pairs of rolls, an external frame, and a control console; The two pairs of rolls include a left roll pair formed by an upper roll (17-1) located to the left of the upper universal joint (15-2) and a lower roll (17-2) located to the left of the lower universal joint (15-1), and a right roll pair formed by an upper roll (17-1) located to the right of the upper universal joint (15-2) and a lower roll (17-2) located to the right of the lower universal joint (15-1). In the left roll pair, the axes of the upper roll (17-1) and the lower roll (17-2) are parallel; in the right roll pair, the axes of the upper roll (17-1) and the lower roll (17-2) are parallel. The distance between the upper roll (17-1) and the lower roll (17-2) in each roll pair is equal to the thickness of the magnesium alloy slab (14) to be processed. The lower roll (17-2) passes through a lower bearing seat (25-2), a lower bearing cover (26-2), and a middle... The lower bearing housing (12-2) and the lower bearing cover (13-2) are fixed to the outer frame. The upper roll (17-1) is fixed to the movable crossbeam (11) through the upper bearing housing (25-1), the upper bearing cover (26-1), the upper bearing housing (12-1), and the upper bearing cover (13-1) to adjust the gap between the upper and lower rolls. The two pairs of rolls are arranged symmetrically in the outer frame, and the power of the two pairs of rolls comes from a single electric motor. The two upper rolls (17-1) and the two lower rolls (17-2) are connected by universal joints to realize mechanical transmission. The upper universal joint (15-2) is arranged between the upper bearing housing (12-1) and the upper bearing cover (13-1), and the lower universal joint (15-1) is arranged between the lower bearing housing (12-2) and the lower bearing cover (13-2). The external frame includes a base (18), a column (27), a base connecting bolt (19), two lower bearing seats (25-2), two lower bearing covers (26-2), a lower bearing fastening bolt (16-1), a central lower bearing seat (12-2), a central lower bearing cover (13-2), a central bearing fastening bolt (28), a central upper bearing seat (12-1), a central upper bearing cover (13-1), a movable crossbeam (11), a transmission load-bearing screw (10), an upper seat (24), an upper seat connecting bolt (23), two upper bearing covers (26-1), two upper bearing seats (25-1), and an upper bearing fastening bolt. (16-2), center gear (8-3), left gear (8-1), right gear (8-2), transmission key (9), gear cover (22), center gear shaft (21), rotating wheel (7), base (18) and column (27) are fixed by base connecting bolt (19), lower bearing seat (25-2) and lower bearing cover (26-2) are connected and fixed on base (18) by lower bearing fastening bolt (16-1), and are symmetrically arranged on the left and right sides of base (18), and the center lower bearing seat (12-2) and center lower bearing cover (13-2) are connected and fixed by center bearing fastening bolt (28). On the base (18), and arranged in the middle of the base (18), the upper bearing seat (25-1) and the upper bearing cover (26-1) are connected and fixed on the movable crossbeam (11) by the upper bearing fastening bolt (16-2), and are symmetrically arranged on the left and right sides of the movable crossbeam (11). The central upper bearing seat (12-1) and the central upper bearing cover (13-1) are connected and fixed on the movable crossbeam (11) by the central bearing fastening bolt (28), and are arranged in the middle of the movable crossbeam (11). The upper seat (24) is connected to the column (27) by the upper seat connecting bolt (23). The transmission bearing screw (10) is connected to the movable crossbeam (18) by the upper bearing connecting bolt (23). 11) is connected to the T-slot and is connected to the upper seat (24) by a thread, and is meshed and driven with the left gear (8-1) and the right gear (8-2) by a transmission key (9). The left gear (8-1) and the right gear (8-2) are respectively arranged on the left and right sides of the center gear (8-3) and are connected to the center gear (8-3) for transmission. The center gear shaft (21) is connected to the center gear (8-3) for transmission and is connected to the rotating wheel (7). The gear cover (22) is connected to the upper seat (24) to cover and restrict the up and down movement of the left gear (8-1), the right gear (8-2) and the center gear (8-3). The control console is connected to the outer frame and two pairs of rollers via wires (20). The control console consists of an electronic display screen (1), a start button (3), a stop button (4), an emergency brake button (2), a parameter setting panel (5), a control console body (6), and wires (20). The included angle between the axes of the two upper rolls (17-1) and the included angle between the axes of the two lower rolls (17-2) are both α, where 0°<α≤30°; When the device is in operation, the angle between the rolling direction of the magnesium alloy strip and the rotational linear velocity direction of the two pairs of rolls is α / 2.

2. The installation method of the device according to claim 1, characterized in that, The installation method is as follows: Secure the column (27) to the corresponding position on the base (18) using the base connecting bolts (19); arrange the lower bearing housing (25-2) symmetrically on the left and right sides of the base (18) and secure it with bolts; arrange the central lower bearing housing (12-2) in the middle of the base (18) and secure it with bolts; arrange the lower roller (17-2) of the two pairs of rollers in the lower bearing housing (25-2) and the central lower bearing housing (12-2) and apply graphite oil solution for lubrication, and connect them with the lower universal joint (15-1); secure the lower bearing cover (26-2) to the lower bearing housing (25-2) using the lower bearing fastening bolts (16-1), and simultaneously connect the central lower bearing cover (13-2) to the central lower bearing housing. The bearing seat (12-2) is fastened with the central bearing fastening bolt (28); the upper bearing seat (25-1) is symmetrically arranged on the left and right sides of the movable crossbeam (11) and fastened with bolts; the central upper bearing seat (12-1) is arranged in the middle of the movable crossbeam (11) and fastened with bolts; the upper roll (17-1) of the two pairs of rolls is arranged in the upper bearing seat (25-1) and the central upper bearing seat (12-1) and coated with graphite oil solution for lubrication, and connected with the upper universal joint (15-2); the upper bearing cover (26-1) is fastened to the upper bearing seat (25-1) with the upper bearing fastening bolt (16-2), and the central upper bearing cover (13-1) is fastened to the central upper bearing seat (12-1). Tighten the central bearing fastening bolt (28); screw the transmission bearing screw (10) into the corresponding threaded hole of the upper seat (24) and keep the two transmission bearing screws (10) screwed in by the same amount; connect the left gear (8-1) and the right gear (8-2) to the corresponding transmission bearing screw (10) through the transmission key (9); connect the central gear shaft (21) to the central gear (8-3) through the transmission key (9); arrange the central gear shaft (21) in the corresponding hole of the upper seat (24); arrange the central gear (8-3) between the left gear (8-1) and the right gear (8-2) to achieve gear meshing transmission; install the gear cover (22) in the corresponding position of the upper seat (24) to achieve left-right gear meshing transmission. Limiting the side gear (8-1), right gear (8-2) and center gear (8-3); installing the transmission bearing screw (10) in the corresponding T-slot of the movable crossbeam (11) to achieve the combination of the upper roll (17-1), movable crossbeam (11), transmission bearing screw (10), upper seat (24), left gear (8-1), right gear (8-2) and center gear (8-3) of the two pairs of rolls; installing the movable crossbeam (11) in the space surrounded by the column (27) to achieve the corresponding size clearance fit between the movable crossbeam (11) and the column (27), and at the same time, installing and fastening the upper seat (24) to the corresponding position of the column (27) through the upper seat connecting bolt (23) to complete the overall assembly of the device;Install the rotating wheel (7) on the central gear shaft (21) to connect the rotating wheel (7), central gear (8-3), left gear (8-1), right gear (8-2), transmission bearing screw (10), and movable crossbeam (11). Finally, rotate the rotating wheel (7) to adjust the height of the movable crossbeam (11) and control the gap between the upper and lower rollers to be equal to the required thickness of the magnesium alloy strip.

3. The installation method according to claim 2, characterized in that, Before installation, the device for suppressing edge cracking of magnesium alloy strip during rolling with symmetrically arranged rolls is coated with graphite oil solution to increase lubricity on the outer surfaces of the two pairs of rolls, the outer surface of the left gear (8-1), the outer surface of the center gear (8-3), the outer surface of the right gear (8-2), the outer surface of the transmission bearing screw (10), and the contact surface between the movable crossbeam (11) and the column (27).

4. A method for rolling magnesium alloy sheet using a device for suppressing edge cracking during the rolling of magnesium alloy sheet and strip as described in claim 1, characterized in that, The rolling method is as follows: (1) The pretreated magnesium alloy slab (14) is placed in an electric heating furnace at a temperature of 100~300℃ and kept at that temperature for 0.5 h~1 h to obtain a preheated magnesium alloy slab (14). (2) Set the temperature of the rolls within the range of room temperature to 250°C and keep them in a preheated state; (3) Take the preheated magnesium alloy slab (14) out of the electric heating furnace and send it into the preheated device from the feeding side. Start the device to make the magnesium alloy slab (14) undergo a symmetrical rolling process. After cleaning with acetone and anhydrous ethanol in sequence, blow dry with a hair dryer or air dry naturally before use.

5. The rolling method according to claim 4, characterized in that, The specific method for the preprocessing is as follows: (1) Use 600 grit sandpaper to polish the surface of the magnesium alloy slab (14) to be treated to remove oil stains, and then use 800 grit, 1000 grit and 1200 grit sandpaper in sequence to polish to ensure that the surface of the magnesium alloy slab (14) to be treated is smooth. (2) Wipe and clean with acetone, then dry with a hair dryer; (3) Next, wipe and clean with anhydrous ethanol and then dry with a hair dryer; (4) Apply graphite oil solution to the surface of magnesium alloy slab (14) to obtain pretreated magnesium alloy slab (14).

6. The rolling method according to claim 4, characterized in that, If a magnesium alloy sheet or strip with the target thickness cannot be obtained by single-pass symmetrical rolling, the magnesium alloy sheet or strip obtained in the previous pass is reheated to 100~300℃ and held for 10~30 minutes. Then, symmetrical rolling is performed again and the above process is repeated to obtain magnesium alloy sheet or strip with the required thickness.

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