Apparatus and method for producing weak basal texture magnesium alloy sheet strip by skew rolling

Abstract

The present application belongs to the technical field of light metal plastic forming, and particularly relates to a device and method for preparing fine-grain weak-texture high-performance magnesium alloy plate strip by inclined rolling. Through the device and the processing method, shear deformation of the magnesium alloy blank occurs in the processing process, thereby realizing grain refinement, improving the room temperature mechanical properties of the magnesium alloy, and expanding the application range of the magnesium alloy. The present application deflects the C-axis of the magnesium alloy through the inclined rolling channel, effectively weakens the basal plane texture of the magnesium alloy, refines the grains, and improves the mechanical properties of the magnesium alloy; the lifting speed of the gear lifting device and the rotating speed of the round roller can be adjusted, and the roller is a circular cone type. In the rotary extrusion, the extrusion thickness of the plate is different, and the center position of the circular cone is constantly changed under the action of the gear lifting device, thereby playing a certain eccentric role, further enhancing the deflection degree of the magnesium alloy C-axis to the maximum radius of the circular cone roller. The weakening effect of the magnesium alloy rod grain texture is more significant.

Description

Technical Field

[0001] This invention belongs to the field of light metal plastic forming technology, specifically relating to an apparatus and method for preparing fine-grained, weakly textured high-performance magnesium alloy plates and strips by inclined roll forming. Background Technology

[0002] Magnesium alloys are the lightest metallic structural materials used in practical applications. Due to their low density, high specific strength and stiffness, strong electromagnetic shielding ability, good vibration damping performance, abundant resources, dimensional stability, excellent damping, casting performance, machinability, easy recyclability, and pollution-free nature, magnesium alloys are receiving increasing attention. Currently, magnesium alloys play a significant role in achieving lightweighting, reducing energy consumption, and mitigating environmental pollution, and are being increasingly widely used in the automotive, defense, aerospace, electronics, and machinery industries, as well as in household goods and sporting goods. The application prospects of magnesium alloys are very promising, while simultaneously placing higher demands on their performance.

[0003] However, the biggest obstacle to the plastic deformation of magnesium and magnesium alloys with their close-packed hexagonal structure is the limited room-temperature slip system, resulting in poor macroscopic plasticity. At room temperature, the geometric slip system of magnesium crystals cannot fully meet the requirements for deformation; only when the temperature rises above 220℃ can magnesium alloys achieve better deformation capacity. Therefore, hot rolling of magnesium alloy sheets and strips requires repeated heating. Compared with the production of extruded materials and forgings, the rolling of sheets is more difficult, thus keeping the price of magnesium alloy sheets and strips high, severely restricting their application and market expansion. Developing efficient and economical magnesium alloy sheet and strip processing technologies, industrializing the dominant production technologies for magnesium alloy sheets and strips, significantly reducing production costs, and expanding the market and output of magnesium alloys have become an industry consensus.

[0004] Therefore, it is essential to invent an effective method for preparing fine-grained, weak-texture high-performance magnesium alloys by inclined roll rolling, thereby expanding the application range of magnesium alloys and developing high-performance magnesium alloys and their forming and processing technologies. Summary of the Invention

[0005] The present invention aims to solve the above problems and provides an effective apparatus and method for preparing fine-grained, weakly textured high-performance magnesium alloy plates and strips by inclined roll rolling. Through the apparatus and processing method, the magnesium alloy billet undergoes shear deformation during processing, thereby achieving grain refinement, improving the room temperature mechanical properties of magnesium alloys, and expanding the application range of magnesium alloys.

[0006] This invention is achieved through the following technical solution: an apparatus for preparing fine-grained, weakly textured high-performance magnesium alloy sheet and strip by inclined rolling, comprising an inclined rolling device, a power device, a feeding and discharging device, a gear lifting device, and a synchronous lifting device; the inclined rolling device includes a frustum-shaped roller and a base shell; the inner cavity of the base shell has a semi-circular arc structure, the frustum-shaped roller is rotatably mounted at the center of the arc inside the base shell via a horizontally set frustum shaft, the base shell has a feeding area with a plate-shaped cavity extending horizontally outward along the tangent of the bottom of the semi-circular arc, the inner wall of the semi-circular arc structure has a frustum-shaped structure and forms an inclined rolling area with the side of the frustum-shaped roller; a pair of vertical lifting tracks are opened on the two bottom surfaces of the inner wall of the semi-circular arc structure, the two ends of the frustum shaft pass through the pair of lifting tracks respectively, and a central gear is installed at both ends of the frustum shaft, wherein the central gear located on the right side is rotatably connected to the frustum shaft (which can be achieved through bearings and bushings to ensure that the lifting movement and the rotation of the frustum-shaped roller are mutually controlled). (Not affected), the central gear on the left is fixedly connected to the frustum shaft; the gear lifting device includes a fixed base, a connecting rod rotatably mounted on the fixed base at one end and equipped with a drive mechanism, an eccentric gear eccentrically mounted on the other end of the connecting rod and meshing with the central gear on the right, a crank rotatably connected between the center of the eccentric gear and the right end of the frustum shaft, and the connecting rod and the eccentric gear are rotatably connected; the power device is installed on the top of the synchronous lifting device, including a motor, a motor rotating shaft and a gear mounted on the motor rotating shaft; the gear meshes with the central gear on the left; the synchronous lifting device can lift synchronously with the gear lifting device; the area between the semi-circular top of the base shell and the side of the frustum roller is the extrusion zone; the area corresponding to the side of the frustum roller and the inner bottom surface of the feeding zone is equipped with a heating device; the feeding and discharging device includes a feeding port conveyor belt at the entrance of the feeding zone and a discharging port conveyor belt at the exit of the extrusion zone III.

[0007] The conveyor belt should be in close contact with the inlet and outlet to facilitate the successful feeding of the blank into the rollers and the output of the finished product after the movement is completed. The direction of movement of the conveyor belt should be consistent with the tangent direction at point A on the roller.

[0008] Furthermore, the surface roughness of the power unit, gears, pads, and upper surface of the base all reach Ra0.16~0.4μm, and the rotational speed of the device is 0.2-0.5r / s during operation.

[0009] Furthermore, a rolling extrusion channel is formed between the frustum-shaped roller and the inner cavity of the base shell. From left to right and surrounding the frustum-shaped roller, there are sequentially the conveyor belt feeding area, the inclined rolling area, and the extrusion area. As the magnesium alloy billet is conveyed by the conveyor belt, the friction generated by the contact between the conveyor belt and the frustum-shaped roller, the surface of the magnesium alloy billet, and the lower surface of the inner cavity of the base shell causes the magnesium alloy billet to deform and reach the inclined rolling area. Under the action of the frustum-shaped roller and the arc-shaped surface of the inner cavity of the base shell, because the roller is frustum-shaped, the thickness of the sheet / strip of the magnesium alloy billet is inclined along the frustum surface during forming. Simultaneously, under the action of the gear lifting device, the frustum-shaped rollers continuously rise and fall, generating eccentric extrusion. This causes the magnesium alloy to deform towards the maximum radius of the frustum-shaped rollers. Under this multi-directional rolling, the c-axis of the magnesium alloy billet grains deflects towards the maximum radius of the frustum-shaped rollers, weakening the texture and refining the grains. Due to the action of the gear lifting device and the special design of the frustum-shaped rollers, the overall friction of the magnesium alloy billet varies, creating a difference between the friction generated during the extrusion process and the friction generated by the billet. This further promotes differential flow of the billet, generating shear extrusion deformation to weaken its basal texture. Furthermore, it refines the grains, achieving the purpose of weakening the basal texture.

[0010] Finally, through the extrusion zone, the magnesium alloy billet reaches the desired high-performance, weakly textured, fine-grained magnesium alloy sheet and strip. This apparatus achieves the preparation of fine-grained, weakly textured high-performance magnesium alloys through inclined rolling.

[0011] Furthermore, when the magnesium alloy sheet and strip are deformed, the finished product is conveyed to the target area by the discharge conveyor belt, and the frustum-shaped rollers of the device are adjusted to the lowest position to prepare for the next sheet extrusion.

[0012] A method for preparing fine-grained, weakly textured high-performance magnesium alloy sheet and strip by inclined roll rolling includes the following steps:

[0013] S1. Pretreatment of magnesium alloy billet:

[0014] S1-1. Process the magnesium alloy billet into rectangular magnesium alloy sheet and strip, and polish the surface of the magnesium alloy sheet and strip with 600-grit sandpaper to remove oil stains. Then polish with 800-grit, 1000-grit, and 1200-grit sandpaper in sequence until the surface of the magnesium alloy sheet and strip is smooth.

[0015] S1-2. Mix acetone and anhydrous ethanol in a cleaning tank at a volume ratio of 3:2 and stir until homogeneous to prepare a cleaning solution.

[0016] S1-3. Immerse the magnesium alloy plate and strip prepared in step S1-1 into the cleaning solution prepared in step S1-2, place the cleaning tank on an ultrasonic cleaner and ultrasonically clean the magnesium alloy plate and strip for 60 minutes, then take out the magnesium alloy plate and strip and clean it with anhydrous ethanol, and finally dry it with a hair dryer.

[0017] S1-4. Coat the surface of the magnesium alloy sheet and strip prepared in step S1-3 with graphite oil solution for later use.

[0018] S2. Preheating of magnesium alloy sheet and strip: Set the heating temperature of the vacuum atmosphere heating furnace to 450℃. After the furnace temperature reaches the set temperature, put the magnesium alloy sheet and strip into the heating furnace and keep it at that temperature for 3 hours.

[0019] S3. Lubrication, assembly, and preheating of the dynamic torsional extrusion forming device:

[0020] S3-1, Lubrication: Apply graphite oil solution to the surface of the frustum-shaped roller, the surface of the motor rotating shaft, the surface of all gears, the inside of the base housing, and the inside of the extrusion channel;

[0021] S3-2, Assembly:

[0022] First, fix the synchronous lifting device to the left side of the inclined roller device. After installing the motor bearing on the right side of the motor's rotating shaft, place it on two supports, ensuring the top of the synchronous lifting device is tightly against the pad. Then, install them together with fixing screws and fix them to the pad. Next, install the gear on the far right end of the right motor's rotating shaft and install it with a flat key. Then, install the right-side inclined roller device. After vertically placing the frustum-shaped roller at the center of the inner cavity of the base shell, insert the frustum shaft into the center of the frustum-shaped roller and tighten it with a flat key. Place it in the shaft's lifting track, and install the center gear on the far left of the frustum shaft roller, meshing it with the motor's gear. Then, install the gear lifting device on the right side of the frustum roller, so that the gear lifting device and the synchronous lifting device can lift and lower synchronously. Finally, install the inlet and outlet conveyor belts, with the inlet and outlet positions aligned with the horizontal tangent of the frustum after rotation.

[0023] S3-3. Preheating: Control the temperature of the heating device to 300~500℃, and keep it warm for 2~4 hours after reaching the set temperature, so that it can be used in the next step.

[0024] S4. The frustum-shaped roller and the inner cavity of the base housing form a rolling extrusion channel, which includes three areas: the feeding area, the inclined rolling area, and the extrusion area.

[0025] S4-1. Place the magnesium alloy sheet / strip on the feed conveyor belt, transporting it to the rotary extrusion zone. Operate the gear lifting device to cause the frustum roller to move up and down. Since the initial sheet thickness is just right to fit into the gap between the frustum roller and the inner cavity of the base shell, the frustum roller rotates, and the magnesium alloy sheet / strip begins to be extruded under the influence of friction. Because the roller is frustum-shaped, the extrusion depth of the sheet is different in the transverse direction. The gear lifting device acts on the frustum roller; the synchronous lifting device and the gear lifting device perform the lifting process synchronously, during the lifting cycle... In the process, the rolling degree of the magnesium alloy sheet and strip increases, and when the magnesium alloy sheet and strip is about to be extruded, the gear lifting device completes one cycle of operation, and the frustum-shaped roller returns to its initial position, ultimately forming a magnesium alloy sheet and strip with uniform thickness. In the extrusion space, the c-axis of the magnesium alloy billet deflects at the maximum radius of the frustum-shaped roller, weakening the texture and grains to achieve further refinement. When the magnesium alloy sheet and strip reaches the extrusion zone, it is further extruded to obtain the desired uniform magnesium alloy sheet and strip. During the rotary extrusion forming process, the temperature of the heating device is controlled at 300~500℃.

[0026] S4-2. Take out the magnesium alloy sheet and strip obtained in step S4-1, polish its surface with sandpaper, clean the magnesium alloy sheet and strip with the cleaning solution prepared in step S1-2, clean it a second time with anhydrous ethanol, and dry it with a hair dryer to obtain a fine-grained, weak-textured high-performance magnesium alloy sheet and strip that can be directly put into use.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1. The inclined rolling channel deflects the C-axis of the magnesium alloy, effectively weakening the basal texture of the magnesium alloy, refining the grains, and improving the mechanical properties of the magnesium alloy.

[0029] 2. Both the lifting speed of the gear lifting device and the rotation speed of the roller are adjustable. The roller is frustum-shaped, and during rotational extrusion, the extruded thickness of the sheet metal varies. Furthermore, the gear lifting device causes the center position of the frustum to continuously change, creating a certain eccentric effect. This further enhances the deflection at the maximum radius of the frustum roller along the C-axis of the magnesium alloy, resulting in a more significant weakening effect on the grain texture of the magnesium alloy rod. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the main structure of the device described in this invention;

[0031] Figure 2 This is a side view of the device described in this invention.

[0032] Figure 3 This is a schematic diagram of the main structure of a frustum-shaped roller.

[0033] Figure 4 This is a side view of the frustum-shaped roller.

[0034] Figure 5 This is a schematic diagram of the strip and sheet material during the rolling process;

[0035] Figure 6 for Figure 1 Schematic diagram of the synchronous lifting device;

[0036] Figure 7 A schematic diagram of the outer casing of the inclined roll assembly;

[0037] Figure 8 This is a schematic diagram of the billet shape inside the roll extrusion channel;

[0038] In the diagram: 1-Frustum roller; 2-Base housing; 3-Gear; 4-Outlet conveyor belt; 5-Eccentric gear; 6-Connecting rod; 7-Baffle; 8-Inlet conveyor belt; 9-Magnesium alloy strip; 10-Fixed base; 11-Lifting rail; B-Heating device; 12-Motor; 13-Bracket; 14-Pad; 15-Synchronous lifting device; 16-Frustum shaft; 17-Fixing screw; 18-Motor bearing; 19-Motor rotating shaft; 20-Center gear; 21-Crank; 22-Base plate; 23-Limiting rail; 24-Lifting gear; 25-Mounting base; 26-First connecting rod; 27-First eccentric gear; 28-First crank; 29-Support column; 30-Top plate.

[0039] Ⅰ-Feeding zone; Ⅱ-Inclined rolling zone; Ⅲ-Extrusion zone. Detailed Implementation

[0040] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0041] An apparatus for preparing fine-grained, weak-textured high-performance magnesium alloy sheet and strip by inclined rolling includes an inclined rolling device, a power unit, a feeding and discharging device, a gear lifting device, and a synchronous lifting device, wherein:

[0042] The inclined rolling device includes a frustum-shaped roller 1 and a base housing 2. The base housing 2 is placed flat on the ground, and the frustum-shaped roller 1 is placed at the center of the arc of the base housing.

[0043] The power unit includes a motor 12, a bracket 13, a pad 14, a fixing screw 17, a motor bearing 18, and a motor rotating shaft 19. Two brackets 13 are mounted on the pad 14, the motor bearing 18 is fitted onto the motor rotating shaft 19 and placed on the brackets 13, the motor rotating shaft 19 is mounted in the motor 12, the motor 12 is mounted on the brackets 13, and the synchronous lifting device is connected and fixed to the pad 14 with the fixing screw 17. The base shell 2 extends horizontally outward along the tangent of its semi-circular bottom, and a side plate and a baffle 7 are installed on the extension, together forming a plate-shaped cavity feeding area I. A heating device B is provided on the area corresponding to the side of the frustum-shaped roller 1 on the inner wall of the semi-circular structure and on the inner bottom surface of the feeding area I.

[0044] The feeding and discharging device consists of a feeding inlet conveyor belt 8 and a discharging outlet conveyor belt 4. Both the feeding inlet conveyor belt 8 and the discharging outlet conveyor belt 4 are in close contact with the feeding and discharging outlets of the inclined roller device. The length L1 of the parallel channel of the base (feeding area I) in contact with the feeding and discharging outlets is 15-25mm. The speed V1 of the feeding inlet is 3-5mm / s, and the speed V2 of the discharging outlet conveyor belt is the same as the speed of the feeding inlet conveyor belt.

[0045] The gear lifting device consists of a fixed base 10, a connecting rod 6, a gear 3, an eccentric gear 5, and a lifting track 11. Its function is to move the frustum eccentrically, increasing the deformation of the magnesium alloy. The radii of gear 3, eccentric gear 5, and the central gear mating with the frustum are all 20-25mm. The synchronous lifting device is identical to the gear lifting device (specific installation is handled by...). Figure 6As shown, the system includes a base plate 22, a pair of limiting rails 23 vertically mounted on the base plate 22, lifting gears 24 with both ends of the rotating shaft locked within the limiting rails 23, a mounting base 25 located on the base plate 22, a first connecting rod 26 rotatably mounted on the mounting base 25 at one end and equipped with a drive mechanism, a first eccentric gear 27 eccentrically mounted on the other end of the first connecting rod 26 and meshing with the lifting gears 24, the first eccentric gear 27 and the first connecting rod 26 being rotatably connected, and a first crank 28 rotatably connected to the center of the first eccentric gear 27 and the center of the lifting gear 24; the rotating shaft of the lifting gear 24 is vertically connected (the rotating shaft and the support column can be connected by a bushing) to a pair of support columns 29, and a top plate 30 is mounted on the top of the support columns 29; the lifting gear 24 and the rotating shaft are rotatably connected. The top plate 30 is connected and limited by limit rods located at its four corners (to prevent the support columns from rotating and ensure smooth lifting). The power unit is installed on the top plate 30. Its function is to keep the gear at the rotating shaft of the motor and the central gear of the driving platform in a meshed state. The rotational speeds of the two gears are W1 and W2, which are the same at 0.2-0.5 r / s to keep the platform eccentric. The rotational speeds of W1 and W2 are the same at 0.2-0.5 r / s, which are also the same as the rotational speeds of the platform shaft 16 and the rotating shaft of the motor (W3 and W4, respectively), both 0.2-0.5 r / s. In the initial stage, the height H1 from above the base to below the pad at the highest point is 50-70 mm. The up-and-down movement speed of the gear lifting device is V4, which is 5-10 mm / s. Its speed is the same as the lifting speed V5 of the synchronous lifting device.

[0046] Furthermore, the rolling extrusion channel is divided into three zones from top to bottom: feeding zone I, inclined rolling zone II, and extrusion zone III. In feeding zone I, the magnesium alloy strip 9 moves forward continuously and uniformly at a speed of V1 (3-5 mm / s) driven by the feed inlet conveyor belt 8. Upon reaching inclined rolling zone II, the magnesium alloy strip 9 adjusts its feeding position under the action of the baffle 7 and enters zone II through the acceleration of the rotating frustum and the feed inlet conveyor belt. Under the action of the gear lifting device, the frustum roller moves up and down at a speed of V4 (5-10 mm / s), and the rotational speed of the frustum roller is V3 (0.2-0.5 r / s). The gear lifting device causes the frustum to constantly perform eccentric motion. Simultaneously, due to the special characteristics of the frustum-shaped roller 1 (R1≠R2, where R1 is 25-30mm and R2 is 15-20mm), and the inherent slope θ1 of the frustum-shaped roller (100°-110°), and the outer shell used to limit the thickness of the sheet, the magnesium alloy billet further deflects towards the maximum radius of the frustum, forcing the c-axis of the magnesium alloy billet to deflect towards the maximum radius of the frustum roller, thus refining the grain size and weakening the texture. Finally, through extrusion zone III, the magnesium alloy billet reaches the desired high-performance magnesium alloy sheet / strip. This device can achieve the preparation of fine-grained, weakly textured magnesium alloys through rolling rotation and extrusion deformation.

[0047] In this specific embodiment, before performing reciprocating torsional extrusion deformation to prepare fine-grained, weakly textured magnesium alloys, the materials and chemical reagents required for the preparation process are carefully selected:

[0048] 1. Magnesium alloy sheet and strip 9: rectangular blank, material selected is AZ31, containing 96% magnesium, 3% aluminum and 1% zinc;

[0049] 2. Sandpaper: Solid.

[0050] 3. Graphite oil solution: a viscous liquid;

[0051] 4. Anhydrous ethanol: Liquid, purity 99.5%;

[0052] 5. Acetone: Liquid, 99% purity.

[0053] A method for preparing fine-grained, weakly textured high-performance magnesium alloy sheet and strip by inclined roll rolling includes the following steps:

[0054] S1. Pretreatment of magnesium alloy billet:

[0055] S1-1. Process the magnesium alloy billet into a rectangular magnesium alloy sheet / strip 9, and polish the surface of the magnesium alloy sheet / strip 9 with 600-grit sandpaper to remove oil stains. Then polish it with 800-grit, 1000-grit, and 1200-grit sandpaper in sequence until the surface of the magnesium alloy sheet / strip 9 is smooth.

[0056] S1-2. Mix acetone and anhydrous ethanol in a cleaning tank at a volume ratio of 3:2 and stir until homogeneous to prepare a cleaning solution.

[0057] S1-3. Immerse the magnesium alloy strip 9 prepared in step S1-1 into the cleaning solution prepared in step S1-2, place the cleaning tank on an ultrasonic cleaner and ultrasonically clean the magnesium alloy strip 9 for 60 minutes, then take out the magnesium alloy strip 9 and clean it with anhydrous ethanol, and finally dry it with a hair dryer.

[0058] S1-4. Coat the surface of the magnesium alloy sheet / strip 9 prepared in step S1-3 with graphite oil solution for later use.

[0059] S2. Preheating of magnesium alloy sheet and strip 9: Set the heating temperature of the vacuum atmosphere heating furnace to 450℃. After the furnace temperature reaches the set temperature, put the magnesium alloy sheet and strip into the heating furnace and keep it warm for 3 hours.

[0060] S3. Lubrication, assembly, and preheating of the dynamic torsional extrusion forming device:

[0061] S3-1, Lubrication: Apply graphite oil solution to the surface of the frustum roller 1, the surface of the motor rotating shaft 19, the surface of all gears, the inner side of the base housing, and the inner surfaces of the extrusion channels I, II, and III;

[0062] S3-2, Assembly:

[0063] First, fix the synchronous lifting device 15 to the left side of the inclined roller device. Install the motor bearing 18 on the right side of the motor rotating shaft 19 of the motor 12 and place it on the two brackets 13, so that the top of the synchronous lifting device 15 is tightly attached to the pad 14. Then, install them together with fixing screws 17 and fix them on the pad 14. Next, install the gear 3 on the rightmost end of the right motor rotating shaft 19 and install it with a flat key. Then, install the right inclined roller device. After vertically placing the frustum roller 1 at the center of the inner cavity of the base housing 2, insert the frustum shaft 16 into the center of the frustum roller 1 and tighten it with a flat key. Place it in the lifting track 11 of the shaft. Install the center gear 20 on the leftmost side of the frustum roller 1 and mesh it with the gear 3 of the motor 12. Then, install the gear lifting device on the right side of the frustum roller so that the gear lifting device and the synchronous lifting device can lift and lower synchronously. Finally, install the inlet and outlet conveyor belts, with the inlet and outlet positions flush with the horizontal tangent of the frustum after rotation.

[0064] S3-3. Preheating: Control the temperature of heating device B to 300~500℃, and keep it warm for 2~4 hours after reaching the set temperature, so that it can be used in the next step.

[0065] S4. The frustum-shaped roller 1 and the inner cavity of the base housing 2 form a rolling extrusion channel, which includes three areas: feeding area I, inclined rolling area II and extrusion area III.

[0066] S4-1. Place the magnesium alloy strip 9 on the feed conveyor belt 8, allowing it to be transported to the rotary extrusion zone. Operate the gear lifting device to cause the frustum roller to move up and down. Since the initial thickness of the sheet material is just enough to fit into the gap between the frustum roller 1 and the inner cavity of the base shell 2, the frustum roller 1 rotates. Driven by friction, the magnesium alloy strip 9 begins to be extruded. Because the roller is frustum-shaped, the extrusion depth of the sheet material is different in the transverse direction. Furthermore, the gear lifting device acts on the frustum roller 1; the synchronous lifting device and the gear lifting device... The lifting process is performed synchronously. During the lifting cycle, the rolling degree of the magnesium alloy strip 9 increases, and when the magnesium alloy strip 9 is about to be extruded, the gear lifting device completes one cycle, and the frustum-shaped roller 1 returns to its initial position, ultimately forming a magnesium alloy strip 9 with uniform thickness. In the extrusion space, the c-axis of the magnesium alloy billet deflects at the maximum radius of the frustum-shaped roller 1, weakening the texture and grains to achieve further refinement. When the magnesium alloy strip 9 reaches the extrusion zone, it is further extruded to obtain the desired uniformly structured magnesium alloy strip 9. During the rotary extrusion forming process, the temperature of the heating device B is controlled at 300~500℃.

[0067] S4-2. Take out the magnesium alloy sheet and strip 9 obtained in step S4-1, polish its surface with sandpaper, clean the magnesium alloy sheet and strip 9 with the cleaning solution prepared in step S1-2, clean it a second time with anhydrous ethanol, and dry it with a hair dryer to obtain a fine-grained weak-textured high-performance magnesium alloy sheet and strip that can be directly put into use. Specific Implementation

[0069] A method for preparing fine-grained, weakly textured high-performance magnesium alloy sheet and strip by inclined roll rolling comprises the following steps:

[0070] (1) Securely install the inclined roller device, feeding and discharging device, gear lifting device, external power device and synchronous lifting device, and ensure that the connection relationship of each part is correct and operated in sequence;

[0071] (2) Polish the outer surface of the AZ31 magnesium alloy sheet and strip blank with 600 grit sandpaper to remove oil stains, and then polish it with 1000, 1200 and 2500 grit sandpaper in sequence to ensure that the surface is clean and smooth; place the polished magnesium alloy block blank in a mixture of acetone and anhydrous ethanol with a volume ratio of 3:2 for ultrasonic cleaning for 30 minutes, then clean it with alcohol and blow it dry with a hair dryer;

[0072] (3) Turn on the vacuum atmosphere heating furnace to preheat the magnesium alloy plate and strip. The preset temperature is 400℃. When the preset temperature is reached, continue to place the magnesium alloy plate and strip billet in the heating furnace for 3 hours.

[0073] (4) Heat the board material. The heating temperature is preset to 400℃. After reaching the preset temperature, continue to keep it warm for 3 hours.

[0074] (5) Apply high-temperature graphite oil solution to the surface of the magnesium alloy sheet / strip for lubrication. The width of the sheet should be consistent with the width of the conveyor belt and the spacing between the two baffles. Place the sheet neatly on the feed inlet conveyor belt.

[0075] (6) In this invention, the surface roughness of the outer surface of the frustum-shaped roller 1 and the inner surface of the base shell 2 is Ra0.08~0.16μm. The material of the frustum-shaped roller 1 is 60SiMnMo, and the hardness is HS45~105. The gear 3, eccentric gear 5, and central gear 20 are all made of 40Cr, and the tooth surface hardness is HB<350. The surface roughness of the pad is Ra3.2~6.4μm, and the surface roughness of the three channels I, II, and III is Ra0.4~0.8μm. The material of the frustum shaft and the rotating shaft is 45 steel after quenching and tempering.

[0076] (7) Turn on the motor and set the pressure to 400MPa. At the same time, turn on the gear lifting device and the synchronous lifting device. The motor drives the frustum roller to rotate at a speed of W3=0.5 r / s. The travel speed of the two lifting devices is V5=10mm / s. Initially, the magnesium alloy billet is deformed to the maximum radius of the frustum by the rolling of the frustum roller. After adding another lifting device, the degree of deformation is further increased, forcing the c-axis of the magnesium alloy strip to deflect and refine the grains. This further intensifies the plastic deformation of the magnesium alloy strip, weakens the texture and refines the grains. Finally, through the extrusion zone III, a uniformly sized plate is obtained under the combined action of the upper surface of the inner cavity of the base shell and the frustum roller, achieving the required magnesium alloy strip size and realizing the processing of magnesium alloy strip.

[0077] (8) Take out the magnesium alloy strip, polish its surface with sandpaper, then place it in a mixture of acetone and anhydrous ethanol in a volume ratio of 3:2 for ultrasonic cleaning, and finally clean it with alcohol and dry it with a hair dryer in cold air.

[0078] Conclusion: The apparatus and process for preparing fine-grained, weakly textured magnesium alloy sheets and strips by rotary extrusion using a frustum roll of this invention significantly reduces the average grain size of the magnesium alloy billet compared to conventional magnesium alloys, effectively weakens the basal texture compared to the initial magnesium alloy bar stock, and effectively improves the mechanical properties of the magnesium alloy. Materials and chemical reagents used: AZ31 magnesium alloy block billet with a diameter d = 50 mm; sandpaper: SiC, 600 mesh, 2 sheets; 1000 mesh, 2 sheets; 1200 mesh, 2 sheets; 2500 mesh, 2 sheets; high-temperature graphite oil solution: C, 500 g; anhydrous ethanol: CH3CH2OH, 1200 ml; acetone: C3H6O, 800 ml.

[0079] The following detailed description, in conjunction with the accompanying drawings, illustrates the principle of obtaining a fine-grained, weakly textured magnesium alloy through the above steps: 1) The feed inlet conveyor belt speed V1 = 3 mm / s is equal to the discharge inlet conveyor belt speed V2, which is less than the horizontal tangential speed V3 = 5 mm / s when the frustum-shaped roller rotates, i.e., V1 = V2 < V3. The diameters on both sides of the roller are different, i.e., R1 ≠ R2. The inclination angle of the frustum is θ1 = 105°. R1 = 30 mm, R2 = 20 mm, and the radius R3 of the base shell should be greater than R1 and R2. R3 = 32 mm. The synchronous lifting device speed V4 is equal to the gear lifting device speed V5, i.e., V4 = V5, where V4 = V5 = 10 mm / s. Furthermore, during the rotation of the gear driven by the power device, the rotational speeds of the two meshing gears W1 = W2 = 0.5 r / s, which is equal to the rotational speed W4 of the motor shaft and also equal to the rotational speed W3 of the central gear driven by the frustum shaft.

[0080] 2) Roller Rotation Extrusion Process: Magnesium alloy sheet and strip are transported to the feed inlet of the inclined roller device by a conveyor belt. Under the influence of the conveyor belt, the sheet and strip enter the inclined roller device. Under the action of friction, the frustum roller and the base contour drive the sheet to move. As the sheet and strip enter the channel, due to the special structure of the frustum and the effect of the arc-shaped shell, the degree of extrusion in the transverse direction is not uniform. Furthermore, under the action of the gear lifting device, the frustum has a certain eccentric movement. The regular lifting and lowering movement of the frustum further intensifies the deformation of the magnesium alloy, achieving the purpose of refining the grains. This causes the magnesium alloy billet to increase in size towards the maximum radius of the frustum roller, changing the billet from a flat shape to a transversely unevenly distributed arc shape. The c-axis of the billet grains deflects, weakening its basal texture and refining the grains. Finally, after passing through the discharge zone III, the deformed billet is further extruded into a flat sheet, further weakening the basal texture and refining the grains.

[0081] Based on the above two principles, the magnesium alloy billet undergoes extensive shearing and extrusion deformation to obtain high-performance magnesium alloy sheet and strip with a weak base texture.

[0082] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An apparatus for preparing fine-grained, weakly textured high-performance magnesium alloy sheet and strip by inclined roll rolling, characterized in that, The device includes an inclined rolling mill, a power unit, a feeding and discharging device, a gear lifting device, and a synchronous lifting device (15); the inclined rolling mill includes a frustum-shaped roller (1) and a base shell (2); the inner cavity of the base shell (2) is a semi-circular arc structure, the frustum-shaped roller (1) is rotatably mounted at the center of the arc inside the base shell (2) through a horizontally set frustum shaft (16), the base shell (2) extends horizontally outward along the tangent of the bottom of the semi-circular arc and has a feeding area I with a plate-shaped cavity, the inner wall of the semi-circular arc structure is a frustum-shaped structure and is connected to the frustum The sides of the shaped roller (1) form an inclined rolling zone II; a pair of vertical lifting tracks (11) are opened on the two bottom surfaces of the inner wall of the semi-circular arc structure. The two ends of the truncated cone shaft (16) pass through the pair of lifting tracks (11) respectively, and a central gear (20) is installed at both ends of the truncated cone shaft (16). The central gear (20) on the right side is rotatably connected to the truncated cone shaft (16), and the central gear (20) on the left side is fixedly connected to the truncated cone shaft (16); the gear lifting device includes a fixed base (10) and is rotatably installed at one end. A connecting rod (6) with a drive mechanism is mounted on a fixed base (10), and an eccentric gear (5) is eccentrically mounted on the other end of the connecting rod (6) and meshes with the right-side central gear (20). A crank (21) is rotatably connected between the center of the eccentric gear (5) and the right end of the frustum shaft (16). The connecting rod (6) and the eccentric gear (5) are rotatably connected. The power unit is mounted on the top of the synchronous lifting device (15) and includes a motor (12), a motor rotating shaft (19), and a motor rotating shaft (19) mounted on the motor rotating shaft (19). Gear (3); the gear (3) meshes with the central gear (20) on the left; the synchronous lifting device (15) can lift synchronously with the gear lifting device; the area corresponding to the side of the semi-circular arc structure inner wall and the frustum roller (1) and the inner bottom surface of the feeding area I are provided with a heating device (B); the area between the semi-circular arc top of the base shell (2) and the side of the frustum roller (1) serves as the extrusion area III; the feeding and discharging device includes a feeding port conveyor belt (8) located at the entrance of the feeding area I and a discharging port conveyor belt (4) located at the exit of the extrusion area III. The synchronous lifting device (15) includes a base plate (22), a pair of limiting rails (23) vertically mounted on the base plate (22), lifting gears (24) with both ends of the rotating shaft locked in the limiting rails (23), a mounting base (25) located on the base plate (22), a first connecting rod (26) rotatably mounted on the mounting base (25) and equipped with a drive mechanism, and a first eccentric gear (27) eccentrically mounted on the other end of the first connecting rod (26) and meshing with the lifting gears (24). The eccentric gear (27) is rotatably connected to the first connecting rod (26). The center of the first eccentric gear (27) is also rotatably connected to the center of the lifting gear (24) by a first crank (28). A pair of support columns (29) are vertically connected to the shaft of the lifting gear (24), and a top plate (30) is installed on the top of the support columns (29). The lifting gear (24) is rotatably connected to the shaft. The top plate (30) is limited by the limiting rods located at the four corners. The power device is installed on the top plate (30).

2. The apparatus for preparing fine-grained, weakly textured high-performance magnesium alloy sheet and strip by inclined roll rolling as described in claim 1, characterized in that, The power unit also includes two brackets (13), fixing screws (17), pads (14) and motor bearings (18); the two brackets (13) are mounted on the pads (14), the motor bearings (18) are sleeved on the motor rotating shaft (19) and mounted on one of the brackets (13), the motor rotating shaft (19) is mounted in the motor (12), the end of the motor (12) is mounted on the other bracket (13), and the top plate (30) of the synchronous lifting device is connected and fixed to the pads (14) with fixing screws (17).

3. The apparatus for preparing fine-grained, weakly textured high-performance magnesium alloy sheet and strip by inclined roll rolling as described in claim 2, characterized in that, The base shell (2) extends horizontally outward along the tangent of the semi-circular bottom, and a side plate and a baffle (7) are installed on the extension, which together form a plate-shaped cavity feeding area I.

4. The apparatus for preparing fine-grained, weak-texture high-performance magnesium alloy sheet and strip by inclined roll rolling as described in any one of claims 1-3, characterized in that, The radii of the gear (3), the eccentric gear (5), and the central gear (20) are the same, which is 20-25mm.

5. The apparatus for preparing fine-grained, weakly textured high-performance magnesium alloy sheet and strip by inclined roll rolling as described in any one of claims 1-3, characterized in that, The truncated cone roller (1) has a slope θ1 of 100°-110° on its side, and the radii R1 of the two bottom surfaces are 25-30mm and R2 is 15-20mm.

6. A method for preparing fine-grained, weak-texture high-performance magnesium alloy sheet and strip by inclined roll forming, comprising the following steps: S1. Pretreatment of magnesium alloy billet: S1-1. The magnesium alloy blank is processed into a rectangular magnesium alloy plate and strip (9), and the surface of the magnesium alloy plate and strip (9) is polished with 600-grit sandpaper to remove oil stains. Then, it is polished with 800-grit, 1000-grit, and 1200-grit sandpaper in sequence until the surface of the magnesium alloy plate and strip (9) is smooth. S1-2. Mix acetone and anhydrous ethanol in a cleaning tank at a volume ratio of 3:2 and stir until homogeneous to prepare a cleaning solution. S1-3. Immerse the magnesium alloy strip (9) prepared in step S1-1 into the cleaning solution prepared in step S1-2. Place the cleaning tank on an ultrasonic cleaner and ultrasonically clean the magnesium alloy strip (9) for 60 minutes. Then take out the magnesium alloy strip (9) and clean it with anhydrous ethanol. Finally, dry it with a hair dryer. S1-4. Coat the surface of the magnesium alloy strip (9) prepared in step S1-3 with graphite oil solution and save it for later use. S2. Preheating of magnesium alloy sheet and strip (9): Set the heating temperature of the vacuum atmosphere heating furnace to 450℃. After the furnace temperature reaches the set temperature, put the magnesium alloy sheet and strip (9) into the heating furnace and keep it warm for 3 hours. S3. Lubrication, assembly, and preheating of the dynamic torsional extrusion forming device: S3-1, Lubrication: Apply graphite oil solution to the surface of the frustum roller (1), the surface of the motor rotating shaft (19), the surface of all gears, the inner side of the base shell, the inner surface of the feeding area I, the inclined rolling area II and the extrusion area III; S3-2, Assembly: First, fix the synchronous lifting device (15) to the left side of the inclined roller device. After installing the motor bearing (18) on the right side of the motor rotating shaft (19) of the motor (12), place it on the two brackets (13) so that the top of the synchronous lifting device (15) is tightly attached to the pad (14). Then, install it together with fixing screws (17) and fix it on the pad (14). Next, install the gear (3) on the right end of the right motor rotating shaft (19) and install it with a flat key. Then, install the inclined roller device on the right side and make the frustum roller (1) vertical. After placing it at the center of the inner cavity of the base shell (2), insert the frustum shaft (16) into the center of the frustum roller (1) and tighten it with a flat key. Place it in the lifting track (11) of the shaft, and install the center gear (20) on the far left of the frustum roller (1) and mesh it with the gear (3) of the motor (12). Then install the gear lifting device on the right side of the frustum roller (1) so that the gear lifting device and the synchronous lifting device (15) can lift and lower synchronously. Finally, install the inlet and outlet conveyor belts, and align the inlet and outlet positions with the horizontal tangent after the frustum rotates. S3-3, Preheating: Control the temperature of the heating device (B) to 300~500℃, and keep it warm for 2~4 hours after reaching the set temperature, so that it can be used in the next step; S4. The truncated cone roller (1) and the inner cavity of the base shell (2) form a rolling extrusion channel, including three areas: feeding area I, inclined rolling area II and extrusion area III; S4-1. Place the magnesium alloy strip (9) on the feed inlet conveyor belt (8) to transport the magnesium alloy strip (9) to the rotary extrusion zone. Operate the gear lifting device to make the frustum roller (1) move up and down. Since the initial thickness of the plate is just enough to fit into the gap between the side of the frustum roller (1) and the inner cavity of the base shell (2), the frustum roller (1) rotates. Driven by friction, the magnesium alloy strip (9) begins to rotate and be extruded. Since the roller is frustum-shaped, the extrusion depth of the plate in the transverse direction is different. The gear lifting device acts on the frustum roller (1). The synchronous lifting device (15) and the gear lifting device perform the lifting process synchronously. During the cycle, the rolling degree of the magnesium alloy strip (9) increases, and when the magnesium alloy strip (9) is about to be extruded, the gear lifting device completes one cycle of operation, and the frustum roller (1) returns to the initial position, finally forming a magnesium alloy strip (9) with uniform thickness; in the extrusion space, the c-axis of the magnesium alloy billet deflects at the maximum radius of the frustum roller (1), weakening the texture and grain to achieve further refinement; when the magnesium alloy strip (9) reaches the extrusion zone III, the magnesium alloy strip (9) is further extruded to obtain the desired uniform magnesium alloy strip (9); during the rotary extrusion forming process, the temperature of the heating device (B) is controlled at 300~500℃; S4-2. Take out the magnesium alloy strip (9) obtained in step S4-1, polish its surface with sandpaper, clean the magnesium alloy strip (9) with the cleaning solution prepared in step S1-2, clean it a second time with anhydrous ethanol, and dry it with a hair dryer to obtain a fine-grained weak-textured high-performance magnesium alloy strip that can be put into use directly.

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