Magnesium alloy plate wave-shaped lining plate rolling method based on micro-grain regulation and control

Abstract

The invention discloses a magnesium alloy plate corrugated lining plate rolling method based on micro-grain regulation and control, and belongs to the technical field of plate rolling forming. The invention aims to solve the problems of high anisotropy, poor calendaring formability and the like of an alloy plate due to strong basal texture of the alloy plate due to formation of corresponding stress on the alloy plate surface and over-small range of a rubbing and rolling area during traditional magnesium alloy rolling. According to the rolling method additionally provided with the corrugated lining plate, the deformation resistance of external friction to the plate in the rolling process is reduced, the loading mode is converted into overall application from local application, and the grain size and distribution of the magnesium alloy plate are effectively controlled by regulating and controlling the diameter and period of the corrugated surface of the corrugated lining plate. And the stress state of the plate is changed, and non-uniform deformation and local dynamic recrystallization nucleation are promoted, so that grains are refined, the basal texture is weakened, and the quality and the overall performance of the rolled plate are greatly improved. The method is suitable for short-process rolling forming of the magnesium alloy plate.

Description

Technical Field

[0001] The invention relates to a metal plate liner rolling method, in particular to a magnesium alloy plate corrugated liner rolling method based on micro-grain regulation, and belongs to the technical field of plate rolling forming. Background Art

[0002] Due to its light weight, high strength and good recyclability, magnesium alloys have shown broad application potential in the aviation, aerospace, automotive and communications industries. However, the performance of magnesium alloys in the plastic deformation process is not ideal, especially when forming, it is easy to produce texture, which increases the difficulty of manufacturing magnesium alloy deformed parts and leads to obvious anisotropy. These factors seriously restrict the wide application of deformed magnesium alloys in the industrial field.

[0003] Rolling technology is an important and efficient choice for manufacturing high-performance metal sheets. In order to further improve the performance of rolled sheet products, special rolling methods such as asynchronous rolling, cross rolling, and liner rolling have been studied and discovered and put into practical use. Asynchronous rolling technology introduces shear deformation by changing the linear speed of the rollers, changes the grain stress state during the sheet rolling process, and changes the relationship between the recrystallization process and the plastic deformation mechanism, thereby changing the grain orientation distribution of the sheet, weakening the base surface texture, and improving the plasticity of the alloy sheet. Cross rolling technology changes the rolling direction to achieve multi-directional deformation of the metal, thereby obtaining a more uniform structure and performance. Liner rolling technology attaches a carbide liner to the upper and lower surfaces of the rolled billet, respectively, and feeds the billet into the roller for rolling at the same time, which can achieve single-pass large reduction rolling, greatly improving rolling efficiency.

[0004] Therefore, it has been a long-term and unremitting pursuit in this field to make progress in the field of high-performance plate rolling forming manufacturing, break the limitations of traditional processes and explore innovative methods and processes. Summary of the invention

[0005] The main purpose of the present invention is to solve the problems of many passes, long process flow and low production efficiency in the existing magnesium alloy sheet rolling process. The present invention proposes a corrugated liner rolling method for magnesium alloy sheet based on micro-grain regulation. Compared with traditional rolling, this method cleverly increases the strain along the ND direction during the rolling process, which can not only effectively weaken the base surface texture of the sheet, but also promote non-uniform deformation and local dynamic recrystallization nucleation, significantly improving the quality and overall performance of the rolled sheet.

[0006] The present invention is achieved through the following technical solutions:

[0007] Step 1: Prepare a magnesium alloy plate with a length and width of l1×w1, a thickness of h1, and a corrugated liner length of l2×w2 (l2>l1, w2>w1) (corrugated surface diameter d, period T);

[0008] Step 2: Grind the contact surface between the alloy plate and the corrugated lining plate;

[0009] Step 3: Use alcohol to rinse the contact surface between the alloy plate and the corrugated lining plate and let it dry;

[0010] Step 4: Spray high-temperature isolation agent on the contact surface of the two corrugated liner plates and the alloy plate to prevent the liner plates and the plate from sticking together during the rolling process;

[0011] Step 5: Stack the upper corrugated lining plate, alloy plate and lower corrugated lining plate in order and fix them with wire while leaving a slight gap;

[0012] Step 6: Adjust the heating furnace to the temperature required for rolling, place the binding assembly in the furnace for preheating, and keep it warm for t;

[0013] Step 7: According to the rolling requirements of the target alloy plate, adjust the rolling mill reduction and the roll speed;

[0014] Step 8: Use a push block to feed the plate into the rolling mill. During the rolling process, the corrugated liner and the alloy plate form a dynamic match, and a slight relative sliding will occur on the contact surface between them.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The traditional method of preparing magnesium alloy fine-grained plates requires multiple rolling processes, and the amount of reduction in each process needs to be accurately calculated. The process is complicated and technically difficult, resulting in low production efficiency. The present invention can efficiently produce the required high-performance magnesium alloy fine-grained plates by only using a corrugated liner for one rolling process;

[0017] 2. Compared with traditional rolling, the method of the present invention can quantitatively adjust the diameter d of the corrugated surface of the corrugated liner, that is, actively regulate the deformation of each part of the plate, so that the plate is subjected to force in both the rolling direction (RD) and the normal direction (ND), promoting the metal deformation flow in the normal direction (ND), thereby weakening the directional texture formed in traditional rolling. The grain orientation changes, reducing the anisotropy of the plate and improving the comprehensive performance of magnesium alloy plate products;

[0018] 3. The method of the present invention can adjust the alignment mode of the corrugated surface of the corrugated liner, change the action cycle T, make the rolling stress of the upper and lower surfaces asymmetrical and symmetrical, change the stress state of each part of the plate during the rolling process, reduce the tensile stress of the plate in the rolling direction (RD), and increase the stress in the normal direction (ND). Reduce the probability of internal damage and edge crack defects caused by excessive deformation, and improve and enhance the quality of the formed plate;

[0019] Fourth, the traditional single-pass rolling mainly makes the plate stressed in the rolling direction (RD). The rolling method of the present invention applies external force to the plate in both the rolling direction (RD) and the normal direction (ND). This two-way force mode significantly increases the probability of micro grain breakage, provides energy for recrystallization nucleation, promotes non-uniform deformation and local dynamic recrystallization nucleation, has a significant grain refinement effect, improves the plasticity and strength of the alloy, and greatly improves the quality and overall performance of the rolled plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of rolling principle of corrugated liner

[0021] Figure 2 Schematic diagram of corrugated liner parameters

[0022] Figure 3 Process flow chart

[0023] Figure 4 Schematic diagram of grain distribution of traditional liner rolling

[0024] Figure 5 Schematic diagram of grain distribution of small diameter corrugated liner

[0025] Figure 6 Schematic diagram of grain distribution during rolling of large diameter corrugated liner

[0026] Figure 7 Schematic diagram of grain distribution during rolling of half-period corrugated liner Specific implementation methods

[0027] Specific implementation method 1: Combination Figure 1 , Figure 2 , Figure 3 The present implementation method is described. The present implementation method comprises an upper roller 1, an upper corrugated liner 2, a metal sheet 3, a push block 4, a lower corrugated liner 5, and a lower roller 6. The upper corrugated liner and the sheet form a moving pair 2-3, and the lower corrugated liner and the sheet form a moving pair 3-5. The present implementation method is completed by the following steps: 1. Prepare a magnesium alloy sheet with a length and width of l1×w1 and a thickness of h1. The length of the corrugated liner is l2×w2. The sliding friction coefficients of the moving pair 2-3 and the moving pair 3-5 are μ1 and μ2 respectively. Figure 1 2-3, 3-5), the diameter of the wave surface d, the period T ( Figure 2); 2. Grind the contact surface between the alloy plate and the corrugated lining plate; 3. Rinse the contact surface between the alloy plate and the corrugated lining plate with alcohol and dry it; 4. Spray high-temperature isolation agent on the contact surface between the two corrugated lining plates and the alloy plate to prevent the lining plates and the plates from sticking together during the rolling process; 5. Stack the upper corrugated lining plate, alloy plate and lower corrugated lining plate in order and fix them with wire and leave a micro-motion gap; 6. Adjust the heating furnace to the temperature required for rolling, place the binding assembly in the furnace for preheating, and keep it warm for t; 7. Adjust the rolling mill pressure and roller speed according to the rolling requirements of the target alloy plate; 8. Use a push block to feed the plate into the rolling mill. During the rolling process, the corrugated lining plate and the alloy plate form a dynamic matching pair, and there will be a slight relative sliding on the contact surface between them.

[0028] Specific implementation method 2: Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 In this embodiment, the small diameter d1 of the corrugated surface of the corrugated liner is designed according to the size of the magnesium alloy sheet, because the stress and deformation of the magnesium alloy sheet during the rolling process are different at different positions where the corrugated liner contacts the roller. By adjusting the different corrugated surface diameters d1, the base surface texture is weakened to different degrees, the grain refinement effect of the alloy surface layer is obvious, and the micro-grain strengthening of the magnesium alloy surface is achieved. The remaining steps are the same as the specific implementation method 1.

[0029] Specific implementation method three: Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 6 To explain this embodiment, the large diameter d2 of the corrugated surface of the corrugated liner is designed according to the size of the magnesium alloy plate, and after rolling, large and small grains are alternately distributed. The alternating distribution of large and small grains improves the strength of the material by increasing the complexity and hindrance of dislocation movement. The fine-grained region effectively hinders dislocations due to the increase in the number of grain boundaries and the increase in tortuosity, and the coarse-grained region provides more space for dislocations to move. This uneven dislocation distribution enhances the overall strength of the material. The coarse-grained region acts as a "bridge" of the grain boundary, which helps to reduce the direct penetration of cracks and improve the toughness of the material. The grain structure of the combination of coarse grains with strong texture and fine grains with weak texture can maintain relatively good elongation while having high tensile strength compared to the uniform structure magnesium alloy. The remaining steps are the same as the specific implementation method one.

[0030] Specific implementation method 4: Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 7In this embodiment, the corrugated liner action cycle T / 2 is designed according to the size of the magnesium alloy plate. The half-cycle corrugated liner rolling technology can achieve a larger deformation in a single-pass processing process. The corrugated liner rolling can more effectively refine the grains, achieve deep grain refinement, and simultaneously improve the strength and plasticity of the material. The remaining steps are the same as the specific implementation method 1.

Claims

1. A method for rolling a magnesium alloy plate corrugated liner based on micro-grain regulation, characterized in that It is achieved through the following steps: Step 1, prepare a magnesium alloy plate with a length and width of l1×w1, a thickness of h1, and a corrugated liner length of l2×w2 (l2>l1, w2>w1) (corrugated surface diameter d, period T); Step 2, polish the contact surface between the alloy plate and the corrugated liner; Step 3, rinse the contact surface between the alloy plate and the corrugated liner with alcohol and dry it; Step 4, spray a high-temperature isolation agent on the contact surface between the two corrugated liners and the alloy plate to prevent the liners and the plates from sticking together during the rolling process; Step 5, stack the upper corrugated liner, alloy plate, and lower corrugated liner in order and fix them with wire and leave a micro-motion gap; Step 6, adjust the heating furnace to the temperature required for rolling, place the binding assembly in the furnace for preheating, and keep it warm for t; Step 7, adjust the rolling mill reduction and roller speed according to the rolling requirements of the target alloy plate; Step 8, use a push block to feed the plate into the rolling mill. During the rolling process, the corrugated liner and the alloy plate form a dynamic matching pair, and there will be a slight relative sliding on the contact surface between them.

2. The method for rolling a magnesium alloy sheet corrugated liner based on micro-grain regulation according to claim 1, characterized in that Changing the stress mode of the alloy plate reduces the tensile stress of the plate in the rolling direction (RD) and increases the stress in the normal direction (ND), which changes the stress state of the alloy plate, promotes the flow of the interface, forms a wavy interface profile, promotes the formation of crystal boundaries, and entangles the crystal boundaries between different grains to form a stable structure, thereby improving the connection strength of the interface and affecting the weakening effect of the basal texture.

3. The method for rolling a magnesium alloy sheet corrugated liner based on micro-grain regulation according to claim 1, characterized in that By changing the corrugated surface diameter d of the corrugated liner, the force between the alloy plate and the corrugated liner can be adjusted under the condition of fixed reduction. Different corrugated surface diameters d will lead to different deformation degrees of the alloy plate during the rolling process, thus producing different strengthening mechanisms.

4. The method for rolling a magnesium alloy sheet corrugated liner based on micro-grain regulation according to claim 1, characterized in that By changing the action period T of the corrugated liner, the corrugated liner promotes non-uniform deformation and local dynamic recrystallization nucleation. Fine grains and coarse grains bear the synergistic effect of plastic deformation respectively during the rolling stage, thereby improving the alloy's work hardening ability.

5. The method for rolling a magnesium alloy sheet corrugated liner based on micro-grain regulation according to claim 1, characterized in that It can roll various specifications of alloy plates, including single-layer plates and multi-layer plates of different thicknesses, from thin sheets to thick plates. It must meet l2>l1, w2>w1, to ensure that the corrugated liner completely covers the alloy plate and has a relatively small sliding amount. It is necessary to select the appropriate rolling speed and corrugated liner type according to the hardness of the alloy plate to meet the actual production needs.

Images