Electroplastic band rolling device and rolling method

Abstract

This invention discloses an electroplastic rolling apparatus and method for sheet metal. By simultaneously setting up a rolling assembly and a current application assembly, not only can current be effectively introduced into the plastic deformation zone of the workpiece, realizing the use of the electroplastic effect of metal to assist in metal rolling and forming, but compared with existing electroplastic rolling mills, the current loop is shortened and the resistance of the current loop is reduced. This allows the workpiece to be loaded with a larger current density under the same power supply and operating conditions, obtaining a more obvious electroplastic effect and effectively improving the plastic forming ability of the workpiece. In addition, since the current application assembly introduces current into roll one and roll two, it plays a certain role in the electric heating of roll one and roll two, thereby realizing the warm rolling forming process of the workpiece. This combines electroplastic rolling and warm rolling, achieving the goal of improving the plasticity of the metal workpiece and improving the mechanical properties of the rolled workpiece.

Description

Technical Field

[0001] This invention relates to the field of metal forming technology, and in particular to a sheet metal electroplastic rolling apparatus and rolling method. Background Technology

[0002] When an electric current is applied to the plastic deformation zone of a metal, it can decrease the metal's resistance to deformation and increase its plasticity during plastic forming. This phenomenon is known as the electroplastic effect. Utilizing the electroplastic effect can not only improve the plastic deformation capacity of metals and increase their forming limits, but also eliminate residual stress, significantly reduce work hardening, and eliminate the need for annealing during forming. Existing research shows that introducing current into the rolling plastic deformation zone of metals can significantly reduce edge cracking in strips and improve their surface quality.

[0003] Currently, researchers have pointed out that when using the electroplastic effect for metal strip rolling, current density is the main factor affecting the electroplastic effect. Specifically, deformation resistance decreases with increasing current density, while edge cracking and surface quality of the strip significantly improve with increasing current density. Furthermore, to obtain a significant electroplastic effect during electroplastic rolling, the current density needs to reach a certain threshold, typically 1000 A / mm². 2 Based on publicly available literature and data, existing electroplastic rolling mills generally suffer from numerous current loop components and excessively high overall loop resistance. This results in insufficient current in the loop, ultimately leading to a much lower than expected current density applied to the plastic deformation zone of the strip, resulting in an unsatisfactory electroplastic effect.

[0004] Based on the above situation, the present invention aims to design a current application technology that can be used in the metal strip rolling process to increase the current density in the plastic deformation zone of the strip metal during the metal strip rolling process and obtain a more obvious electroplastic effect. Summary of the Invention

[0005] The purpose of this invention is to provide a strip electroplastic rolling apparatus and rolling method, which can apply a high-density current to the plastic deformation zone of the strip during the strip rolling process to obtain a more obvious electroplastic effect, thereby solving the problems of numerous current loop components, low applied current density, and unsatisfactory electroplastic effect in existing rolling mills.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] This invention provides a sheet metal strip electroplastic rolling apparatus, comprising:

[0008] frame;

[0009] The rolling assembly includes a first roll and a second roll rotatably mounted on the frame, with the area between the first roll and the second roll forming the workpiece;

[0010] The current application component includes a positive electrode and a negative electrode. The positive electrode is mounted on the inlet side of the forming zone of the rolled piece via a positive electrode mounting mechanism, and the positive electrode is in sliding contact with the first roll. The negative electrode is mounted on the outlet side of the forming zone of the rolled piece via a negative electrode mounting mechanism, and the negative electrode is in sliding contact with the second roll. The positive electrode is used to connect to the positive terminal of a power supply via a first conductive structure, and the negative electrode is used to connect to the negative terminal of a power supply via a second conductive structure, so as to form a current loop between the positive electrode, the first roll, the plastic deformation zone of the rolled piece, the second roll, and the negative electrode, and apply current to the plastic deformation zone of the rolled piece.

[0011] Optionally, the first roll is located directly above the second roll.

[0012] Optionally, the positive electrode is in sliding contact with the position of the first roll near the forming area of ​​the workpiece, and the end face of the positive electrode for contacting the first roll is a curved surface adapted to the outer contour of the first roll.

[0013] The negative electrode makes a sliding contact with the second roll near the forming area of ​​the workpiece, and the end face of the negative electrode that contacts the second roll is a curved surface adapted to the outer contour of the second roll.

[0014] Optionally, the end face of the positive electrode that contacts the first roll is a continuous curved surface extending along the axial direction of the first roll.

[0015] The end face of the negative electrode that contacts the second roll is a continuous curved surface extending along the axial direction of the second roll.

[0016] Optionally, the positive electrode includes a first positive electrode block and a second positive electrode block, which are connected by an insulating block; the contact positions of the first positive electrode block and the second positive electrode block with the first roll correspond to the two side edges of the workpiece, respectively.

[0017] The negative electrode includes a negative electrode block one and a negative electrode block two, which are connected by an insulating block; the contact positions of the negative electrode block one and the negative electrode block two with the roll two correspond to the two side edges of the workpiece.

[0018] Optionally, the positive electrode mounting mechanism includes:

[0019] A position adjustment plate is movably connected to the frame to adjust the posture of the positive electrode relative to the first roll;

[0020] An electrode box is connected to the position adjustment plate. The electrode box is provided with a slide rail that matches the contour of the positive electrode, and the positive electrode is slidably installed in the slide rail.

[0021] An electrode pushing mechanism is provided on the position adjusting plate, and the electrode pushing mechanism is used to press the positive electrode onto the first roller.

[0022] A pressure sensor is mounted on the electrode pushing mechanism to detect the pushing force exerted by the electrode pushing mechanism on the positive electrode.

[0023] The structure of the negative electrode mounting mechanism is exactly the same as that of the positive electrode mounting mechanism.

[0024] Optionally, the conductive structure is a metal terminal block with a circular hole for connecting the circuit; the metal terminal block is slidably installed in the electrode box and located between the electrode pushing mechanism and the positive electrode, so that the metal terminal block is pressed onto the positive electrode by the electrode pushing mechanism.

[0025] The structure of the second conductive structure is exactly the same as that of the first conductive structure.

[0026] Optionally, the roll includes a roll sleeve, a roll core, and an insulating sleeve, wherein the roll sleeve is sleeved outside the roll core, and the insulating layer is provided between the roll sleeve and the roll core;

[0027] The structure of the second roll is exactly the same as that of the first roll.

[0028] The present invention also proposes a method for electroplastic rolling of sheet metal, implemented using the electroplastic rolling apparatus described above, comprising the following steps:

[0029] S1. Make the positive electrode in close contact with the first roll located on the inlet side of the forming zone of the rolled piece, and make the negative electrode in close contact with the second roll located on the outlet side of the forming zone of the rolled piece;

[0030] S2. The positive electrode is connected to the positive terminal of the power supply through a conductive structure one, and the negative electrode is connected to the negative terminal of the power supply through a conductive structure two, so that the positive electrode, the first roll, the plastic deformation zone of the workpiece, the second roll, and the negative electrode form a current loop, so as to apply current to the plastic deformation zone of the workpiece when the first roll and the second roll ...

[0031] Optionally, before step S1, the following steps are also included:

[0032] S0. Based on the physical parameters of the workpiece, the amount of plastic deformation of the workpiece during rolling, and the influence of current-assisted metal plastic forming on the physical properties of the workpiece, set the applied current parameters, and select the corresponding current distribution within the adjustment range of the current density value to simulate the distribution law of the current inside the workpiece when the electroplastic effect occurs, and determine the current density value of the plastic deformation zone of the workpiece.

[0033] The present invention achieves the following technical effects compared to the prior art:

[0034] The electroplastic rolling apparatus and method proposed in this invention simultaneously sets up a rolling component and a current application component. The positive electrode of the current application component is installed on the inlet side of the workpiece forming zone through a positive electrode mounting mechanism and slides in contact with roll one. The negative electrode is installed on the outlet side of the workpiece forming zone through a negative electrode mounting mechanism and slides in contact with roll two. A current loop can be formed between the positive electrode, roll one, the workpiece plastic deformation zone, roll two, and the negative electrode. This not only effectively introduces current into the plastic deformation zone of the workpiece, realizing the use of the electroplastic effect of metal to assist metal rolling and forming, but also, compared with existing electroplastic rolling mills, this invention shortens the current loop and reduces the resistance of the current loop, allowing the workpiece to be loaded with a larger current density under the same power and working conditions, obtaining a more obvious electroplastic effect, and effectively improving the plastic forming capability of the workpiece. In addition, since the current application component introduces current into roll one and roll two, it plays a certain role in electric heating of roll one and roll two, thereby realizing the warm rolling forming process of the rolled piece. It realizes the combination of electroplastic rolling and warm rolling, and achieves the purpose of improving the plasticity of metal rolled pieces and improving the mechanical properties of rolled pieces. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the overall structure of the plate and strip electroplastic rolling apparatus disclosed in the embodiments of the present invention;

[0037] Figure 2 This is a cross-sectional view of the sheet metal electroplastic rolling apparatus disclosed in the embodiments of the present invention;

[0038] Figure 3 This is an assembly principle diagram of the rolling assembly and the current application assembly in the sheet metal electroplastic rolling apparatus disclosed in the embodiments of the present invention;

[0039] Figure 4This is a detailed assembly diagram of the rolling assembly and the current application assembly in the sheet-strip electroplastic rolling apparatus disclosed in the embodiments of the present invention;

[0040] Figure 5 This is an exploded structural diagram of the positive electrode mounting mechanism in the plate-strip electroplastic rolling apparatus disclosed in the embodiments of the present invention;

[0041] Figure 6 This is a schematic diagram of the positive electrode structure suitable for edge rolling of strip in the strip electroplastic rolling apparatus disclosed in the embodiments of the present invention;

[0042] Figure 7 This is a schematic diagram of the structure of a roll in the sheet-strip electroplastic rolling apparatus disclosed in the embodiments of the present invention;

[0043] Figure 8 This is a process flow diagram of the electroplastic rolling method for sheet metal disclosed in the embodiments of the present invention;

[0044] Figure 9 This is a diagram showing the variation of the length of the non-uniform current distribution region with current intensity during the current-assisted metal rolling process disclosed in the embodiments of the present invention.

[0045] Figure 10 This is a diagram showing the relationship between electrode width and length of non-uniform current distribution region during current-assisted metal rolling as disclosed in an embodiment of the present invention.

[0046] Figure 11 This is a diagram showing the relationship between the thickness of the rolled piece and the length of the non-uniform current distribution region during the current-assisted metal rolling process disclosed in the embodiments of the present invention.

[0047] Figure 12 This is a diagram showing the temperature rise at a point on the outer surface of the rolled piece caused by frictional heat, deformation heat, and Joule heat during the current-assisted metal rolling process disclosed in this embodiment of the invention.

[0048] Figure 13 This is a diagram showing the temperature change of the rolled piece under different electrode spacings during the current-assisted metal rolling process disclosed in the embodiments of the present invention.

[0049] Figure 14 The diagram shows the current density distribution in the rolling zone of the workpiece under the condition that the time-varying effect of the excitation current is negligible during the simulated electroplastic rolling process, as disclosed in the embodiments of the present invention.

[0050] The attached figures are labeled as follows:

[0051] 100. Sheet metal strip electrostatic plastic rolling device;

[0052] 1. Frame; 1-1. Support plate; 2. Roll 1; 2-1. Roll sleeve; 2-2. Roll core; 2-3. Screw; 3. Roll 2; 4. Positive electrode; 5. Negative electrode; 6. Continuous curved surface; 7. Positive electrode block 1; 8. Positive electrode block 2; 9. Insulating block; 10. Position adjustment plate; 11. Electrode box; 11-1. Slide rail; 11-2. Electrode box fixing rod; 11-3. Through hole; 12. Electrode pushing mechanism; 13. Metal terminal block; 13-1. Round hole; 14. Rolled workpiece; 15. Position adjustment screw. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] One of the objectives of this invention is to provide a strip electroplastic rolling apparatus that can apply a high-density current to the plastic deformation zone of the strip during the strip rolling process to obtain a more obvious electroplastic effect, thereby solving the problems of numerous current loop components, low applied current density, and unsatisfactory electroplastic effect in existing rolling mills.

[0055] Another objective of this invention is to provide a strip electroplastic rolling method based on the above-mentioned strip electroplastic rolling apparatus, which can apply a high-density current to the strip metal plastic deformation zone during the strip rolling process to obtain a more obvious electroplastic effect.

[0056] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0057] Example 1

[0058] like Figure 1 As shown, this embodiment provides a sheet metal strip electroplastic rolling apparatus 100, including a frame 1,

[0059] The rolling assembly includes a rolling mill assembly and an electric current application assembly. The rolling assembly includes roll 2 and roll 3 rotatably mounted on the mill stand 1. The area between roll 2 and roll 3 is a workpiece forming zone, through which the workpiece 14 passes. The workpiece 14 enters the forming zone through the entrance side and exits through the exit side. When the workpiece 14 exits through the exit side of the forming zone, it has been rolled into shape. The rolling assembly is equipped with a conventional rolling mill power system to drive roll 2 and roll 3 to rotate and complete the rolling operation. The arrangement and working principle of roll 2 and roll 3 are existing technologies and will not be described in detail here. The current application assembly includes a positive electrode 4 and a negative electrode 5. The positive electrode 4 is mounted on the inlet side of the forming zone of the workpiece via a positive electrode mounting mechanism, and slides in contact with roll 2. The negative electrode 5 is mounted on the outlet side of the forming zone via a negative electrode mounting mechanism, and slides in contact with roll 3. The positive electrode 4 is connected to the positive terminal of the power supply via conductive structure 1, and the negative electrode 5 is connected to the negative terminal of the power supply via conductive structure 2, so as to form a current loop between the positive electrode 4, roll 2, the plastic deformation zone of the workpiece, roll 3, and negative electrode 5, and apply current to the plastic deformation zone of the workpiece. Theoretical studies have shown that increasing the current density in the metal plastic deformation zone is an effective method to obtain a more obvious electroplastic effect. The theoretical scheme for the metal electroplastic effect of the above-mentioned strip electroplastic rolling device 100 is implemented as follows:

[0060] The relationship between micro-dislocation slip rate and macro-strain rate is as follows:

[0061] (1)

[0062] In the formula, It is the orientation factor of the crystal slip system; Dislocation density; b It is the Burgers vector; For the activated area; The natural frequency of the vibration of the dislocation line; The distance between barriers along the dislocation line; Let be the effective stress. This is the pre-exponential factor. Based on the relationship curve between the activated area and the effective stress, equation (1) can be simplified to...

[0063] (2)

[0064] When a single-pulse current is applied to a tensile metal in a state of plastic deformation, the flow stress of the metal decreases rapidly. During the time the current is applied, the slip process of dislocations by directional drifting electron pairs is affected. Regarding equation (2), the electron wind generated by the current leads to the effective stress. Add to At the same time, for the pre-exponential factors It had an impact, making Become Therefore, the strain rate during the time the current is applied is

[0065] (3)

[0066] Taking the logarithm of equations (3) and (2) and subtracting them, we get...

[0067] (4)

[0068] because( (relative to) It is very small, so equation (4) can be transformed into

[0069] (5)

[0070] For equation (5) ( Within a short pulse duration, the amount of change is only... Reduced to ,Right now Introducing a sensitivity coefficient for force corresponding to dislocation slip rate.

[0071] (6)

[0072] From equations (5) and (6), we can obtain

[0073] (7)

[0074] Introduction The traction force generated by the drifting electron pair dislocations can be further obtained

[0075] (8)

[0076] By studying the influence of directional drifting electron pairs on the dislocation slip process, the force exerted by the current on a dislocation per unit length can be expressed as:

[0077] (9)

[0078] In the formula The force exerted by drifting electrons on dislocations; The length of the dislocation; n e Electron density; This refers to the electron drift velocity; This represents the dislocation slip velocity; e It is the elementary charge; h It is Planck's constant;J denoted as current density.

[0079] The force and current intensity of drifting electrons on dislocations J Proportional, that is:

[0080] (10)

[0081] In the formula This refers to the electron wind force coefficient. The traction force generated by dislocations in drifting electron pairs. With electronic wind force coefficient The relation is

[0082] (11)

[0083] From equations (9), (10), and (11), we can obtain

[0084] (12)

[0085] Substituting equation (12) into equation (8) yields

[0086] (13)

[0087] Equation (13) is the theoretical formula for the strain rate of a metal under the action of an electric current. It can be seen from equation (13) that during the duration of the pulsed current, the current induces a change in the strain rate of the metal. This change inevitably leads to a change in the flow stress. In other words, the strain rate remains constant during the tensile process of the metal (i.e., the rolled piece 14). This value is preset by the material stretching machine. During non-electric stretching, the strain rate is entirely achieved by external force (tensile force) (i.e., During electrostatic tension, the strain rate is achieved by both external force and current. It is clear that the tension under charged conditions is achieved by external force. Significantly lower than the stretching without electricity This will inevitably lead to a reduction in the metal flow stress under tension. When the electroplastic effect occurs, the strain rate caused by the external force is... ,in( ) is the change in strain rate caused by the electroplastic effect.

[0088] In summary, applying current to the plastic deformation zone of the metal (i.e., rolled piece 14) can effectively promote dislocation slip and improve the metal's plasticity. The higher the current density, the more pronounced the electroplastic effect; the current density and the decrease in strain rate exhibit an exponential relationship.

[0089] Therefore, the above-mentioned plate and strip electroplastic rolling device 100 in this scheme is a current-assisted metal rolling forming device designed based on the dislocation slip thermal activation theory of the metal electroplastic effect. It not only effectively introduces current into the plastic deformation zone of the rolled piece, realizing metal rolling forming assisted by the metal's electroplastic effect, but also, compared with existing electroplastic rolling mills, shortens the current loop and reduces the resistance of the current loop, allowing the rolled piece 14 to be loaded with a larger current density under the same power supply and operating conditions, obtaining a more significant electroplastic effect and effectively improving the plastic forming capability of the rolled piece. Furthermore, because the current application component introduces current into rolls 2 and 3, it plays a certain role in electrically heating rolls 2 and 3, thereby also realizing the warm rolling forming process of the rolled piece 14.

[0090] The specific configuration of the above-mentioned sheet metal electrostatic plastic rolling device 100 is as follows:

[0091] In this embodiment, as a preferred option, roll 2 is located directly above roll 3, with the roll structure distributed vertically. For example... Figure 7 As shown, roll 2 specifically includes a roll sleeve 2-1, a roll core 2-2, and an insulating sleeve. The roll sleeve 2-1 is fitted over the roll core 2-2, and an insulating layer is provided between the roll sleeve 2-1 and the roll core 2-2. Preferably, the roll sleeve 2-1 is composed of two hollow semi-cylinders, which are fastened to the outer circumference of the roll core 2-2 and fixed with screws 2-3. An insulating sleeve is provided at the contact point between the screws 2-3 and the roll sleeve 2-1 to insulate and isolate the screws 2-3 from the roll sleeve 2-1. The structure of roll 3 is exactly the same as that of roll 2, and will not be described again here.

[0092] In this embodiment, the positive electrode 4 slides into contact with the roll 2 near the workpiece forming area. The roll 2's proximity to the workpiece shortens the current path between the positive electrode 4 and the workpiece. The end face of the positive electrode 4 that contacts the roll 2 is a curved surface adapted to the outer contour of the roll 2. Specifically, this curved surface has the same curvature as the roll sleeve 2-1 in the roll 2, ensuring good contact between the positive electrode 4 and the roll surface of the roll sleeve 2-1. Correspondingly, the negative electrode 5 slides into contact with the roll 3 near the workpiece forming area. The end face of the negative electrode 5 that contacts the roll 3 is a curved surface adapted to the outer contour of the roll 3, specifically a curved surface with the same curvature as the roll sleeve in the roll 3, ensuring good contact between the negative electrode 5 and the roll surface of the roll 3.

[0093] In this embodiment, as Figure 5As shown, the end face of the positive electrode 4 that contacts the roll 2 is a continuous curved surface 6 extending along the axial direction of the roll 2. Correspondingly, the end face of the negative electrode 5 that contacts the roll 3 is a continuous curved surface 6 extending along the axial direction of the roll 3. Such positive electrodes 4 or negative electrodes 5 with continuous curved surfaces 6 are mostly used for the full-surface rolling forming of the workpiece 14.

[0094] In this embodiment, in addition to the design of the continuous curved surface 6 described above, the positive and negative electrodes can also be configured as two independent parts (i.e., both the positive and negative electrodes consist of two electrodes) to address the edge cracking problem during strip rolling. Taking the positive electrode 4 as an example, Figure 6 As shown, it includes a first positive electrode block 7 and a second positive electrode block 8, which are separated and connected by an insulating block 9. The contact positions of the first positive electrode block 7 and the second positive electrode block 8 with the first roll 2 correspond to the two side edges of the workpiece 14, allowing the current to mainly flow through both sides of the plastic deformation zone of the workpiece 14, thus suppressing edge cracking during strip rolling. Correspondingly, the negative electrode 5 includes a first negative electrode block 5 and a second negative electrode block 5, which are connected by an insulating block 9. The contact positions of the first negative electrode block 5 and the second negative electrode block 5 with the second roll 3 correspond to the two side edges of the workpiece 14, allowing the current to mainly flow through both sides of the plastic deformation zone of the workpiece 14, thus suppressing edge cracking during strip rolling.

[0095] In this embodiment, the aforementioned positive electrode mounting mechanism includes a position adjustment plate 10, an electrode box 11, an electrode pushing mechanism 12, and a pressure sensor. The position adjustment plate 10 is movably connected to the frame 1 to adjust the posture of the positive electrode 4 relative to the roll 2. The electrode box 11 is connected to the position adjustment plate 10 and has a slide rail 11-1 adapted to the contour of the positive electrode 4. The positive electrode 4 is slidably mounted in the slide rail 11-1. The protrusions on both sides of the slide rail 11-1 limit the movement of the positive electrode 4, ensuring that it can only slide along the extending direction of the slide rail 11-1. The electrode pushing mechanism 12 is disposed on the position adjustment plate 10 and is used to press the positive electrode 4 against the roll 2. The pressure sensor is disposed on the electrode pushing mechanism 12 and is used to detect the pushing pressure exerted by the electrode pushing mechanism 12 on the positive electrode 4. The structure of the negative electrode mounting mechanism is exactly the same as that of the positive electrode mounting mechanism and will not be described again here.

[0096] In this embodiment, the first conductive structure is a metal terminal block 13, which has a circular hole 13-1 for wiring connection. The metal terminal block 13 is slidably installed in the electrode box 11 and located between the electrode pushing mechanism 12 and the positive electrode 4, so that the electrode pushing mechanism 12 presses the metal terminal block 13 onto the positive electrode 4. Generally, the metal terminal block 13 is pressed onto the positive electrode 4 by the electrode pushing mechanism 12, and the auxiliary power supply wire is fixed to the metal terminal block 13 using the circular hole 13-1 and a matching bolt. Then, the metal terminal block 13 introduces the auxiliary current into the positive electrode 4. The structure of the second conductive structure is exactly the same as that of the first conductive structure, and will not be described again here. The metal terminal block 13 is preferably a copper plate.

[0097] In this embodiment, the electrode pushing mechanism 12 in the positive electrode mounting mechanism and the negative electrode mounting mechanism can be an existing electric telescopic rod, electric cylinder, pneumatic cylinder, or hydraulic cylinder with telescopic function. During use, proper insulation and anti-interference measures should be taken. As a preferred option, the electrode pushing mechanism 12 in both the positive and negative electrode mounting mechanisms in this embodiment uses an electric cylinder. The push rod of the electric cylinder passes through the position adjustment plate 10 and the side wall of the electrode box 11, contacting the metal terminal block 13 inside the electrode box 11. An insulating pad is provided between the metal terminal block 13 and the push rod of the electric cylinder. Under the pressure of the corresponding electric cylinder push rod, the metal terminal block 13 makes close contact with the corresponding positive electrode 4 or negative electrode 5, thereby ensuring that the curved surface of the corresponding positive electrode 4 or negative electrode 5 makes close contact with the corresponding roll surface. Generally, a pressure sensor is installed at the end of the electric cylinder push rod. In actual operation, the pressure can be set by the pressure sensor to ensure that the pressure of the electric cylinder push rod on the metal terminal block 13 is constant. As the rolling process of the rolling assembly proceeds, roll 2 and roll 3 remain in a rotating state. Long-term operation will cause wear on the electrode surface, which in turn causes changes in the pressure between the electrode and the roll. This pressure change is sensed by the pressure sensor and transmitted to the electric cylinder. The push rod of the electric cylinder will extend to push the electrode to slide in the slide 11-1 of the electrode box 11, compensating for the electrode wear, thereby making the electrode in close contact with the roll surface and the contact force constant.

[0098] In this embodiment, the position adjusting plate 10 mainly serves to support and fix the electric cylinder and electrode box 11, and also adjusts the contact position between the electrode and the roll surface. The position adjusting plate 10 has threaded holes at both ends and is fixed to the support plate 1-1 of the frame 1 by position adjusting screws 15. Loosening the position adjusting screws 15 allows the position adjusting plate 10 to rotate around the screws. Once the electrode position is adjusted, tightening the position adjusting screws 15 fixes the tilt angle of the position adjusting plate 10. Figure 1As shown, the frame 1 is provided with four support plates 1-1. The four support plates 1-1 are arranged in pairs. The two sets of support plates 1-1 are located on both sides of the frame 1, and are located on the inlet side and outlet side of the rolling assembly, respectively, so as to install the position adjustment plates 10 in the positive electrode mounting mechanism and the negative electrode mounting mechanism, respectively.

[0099] In this embodiment, two electrode box fixing rods 11-2 are also provided on the rear side of the electrode box 11. The electrode box fixing rods 11-2 are connected to the position adjustment plate 10 through bolts, clamps and other connecting structures. When the position adjustment plate 10 is adjusted, it can drive the electrode box 11 to move synchronously, thereby adjusting the contact position between the electrode and the roller surface.

[0100] The following describes in detail the sheet and strip electroplastic rolling method using the sheet and strip electroplastic rolling apparatus 100 described above. The operating steps of the sheet and strip electroplastic rolling method are as follows:

[0101] S1. Based on the physical parameters of the strip and sheet workpiece, the amount of plastic deformation during rolling, and the influence of current-assisted metal plastic forming on the physical properties of the strip and sheet workpiece, set the parameters of the applied auxiliary pulse current. Apply a voltage load of 5000mV to the outer surface of the positive electrode 3, and set the voltage of all nodes on the outer surface of the negative electrode 5 (i.e., the upper edge of the negative electrode) to zero. The initial temperature of the electrode, strip and sheet workpiece, and roll sleeve is 20℃. Set all model outer surfaces to allow natural convection heat transfer with the environment. Other parts are subject to natural boundary conditions; the system will automatically determine and apply boundary conditions without requiring additional settings.

[0102] S2. Within the adjustment range of the auxiliary pulse current density value, a suitable auxiliary pulse current distribution is selected for simulation to obtain the distribution law of the auxiliary pulse current inside the tensile rolled piece 14 when the electroplastic effect occurs, and the auxiliary pulse current density value of the plastic deformation zone of the strip rolled piece is determined. When designing the strip electroplastic rolling device 100, the determination of the distance between the electrode and the die and the selection of the contact method between the electrode and the rolled piece need to consider the current density distribution inside the rolled piece and the electrode. During the current-assisted metal rolling forming process, it is necessary to ensure that the current distribution on the cross-section of the rolled piece in the deformation zone is uniform. The magnitude of the total current applied to the electrode will affect the current distribution at the contact point between the electrode and the rolled piece, and thus affect the current distribution on the cross-section of the rolled piece. Figure 9 The figure shows the variation of the length of the non-uniform current distribution region with current intensity when the original thickness of the rolled piece is 0.7 mm and the applied current value on the electrode ranges from 100 A to 2000 A. Figure 9 It can be seen that when the current is greater than 1400A, the length of the non-uniform current distribution region no longer changes, and the length of the non-uniform current distribution region is only 0.7mm.

[0103] S3. Based on the analysis in step S2, current is introduced to the electrode through a metal terminal block. The selection of the electrode width is crucial for the smooth progress of the current-assisted metal rolling process. On the one hand, good electrical contact is required between the electrode and the workpiece; a wider electrode width provides a larger contact area, which is beneficial for establishing good electrical contact. On the other hand, considering the friction between the workpiece and the electrode, a large contact area means greater frictional force, generating more frictional heat and affecting the smooth progress of the rolling process. Numerical simulation results show that the length of the non-uniform current distribution region is not sensitive to changes in electrode width. The relationship between electrode width and the length of the non-uniform current distribution region is as follows: Figure 10 As shown. By Figure 10 It can be seen that the electrode width is only sensitive to the change in the length of the non-uniform current distribution region when the electrode width is very narrow, less than 0.5 mm; when the electrode width is greater than 0.5 mm, the length of the non-uniform current distribution region remains basically constant and no longer changes with the increase of the electrode width.

[0104] S4. The metal terminal block is pressed against the electrode in contact with the roll by the push rod of the electric cylinder. The pressure of the push rod of the electric cylinder is adjusted by adjusting the pressure sensor to ensure close contact between the electrode and the roll. Under a certain electrode width and current, the greater the thickness of the rolled piece, the farther the current needs to be redistributed uniformly along the cross-section of the rolled piece from the concentration point, and the longer the length of the non-uniform current distribution zone will be. According to the national standard GB 6110-2021 for cemented carbide wire drawing dies, within the thickness range of the rolled piece, the relationship between the thickness of the rolled piece and the length of the non-uniform current distribution zone is obtained by finite element analysis as follows: Figure 11 As shown. By Figure 11 It can be seen that the length of the non-uniform current distribution region increases with the increase of the workpiece thickness, and the two have a linear relationship.

[0105] S5. According to steps S3-S4, the current forms a current loop through the positive electrode 4, the first roll 2, the plastic deformation zone of the workpiece, the second roll 3 and the negative electrode 5, which effectively introduces the current into the plastic deformation zone of the workpiece, shortens the path of the entire current loop and reduces the loop resistance.

[0106] S6. By adjusting the current parameters and the position of the position adjustment plate, the current is mainly distributed on the workpiece 14 and penetrates the plastic deformation zone of the workpiece 14. Figure 12 This describes the temperature rise at a point on the outer surface of the rolled piece caused by frictional heat, deformation heat, and Joule heat. A jump in temperature rise occurs at this point: to the right of the positive electrode 4, at the center of the rolled piece 14, and to the left of the negative electrode 5. This is due to the concentrated current distribution at these three locations. After passing the negative electrode, the periodic heating of the pulsed current causes the surface temperature of the plate to fluctuate periodically and gradually decrease. Figure 12It can be seen that the temperature rise caused by deformation heat is extremely small, mainly because the rolling speed is low; the temperature rise caused by frictional heat is also relatively small, with a maximum of about 24°C; the temperature rise caused by Joule heat is the most significant, accounting for more than 80% of the total temperature rise.

[0107] S7. Based on the analysis in step S6, adjust the tilt angle of the position adjustment plate 10, or fine-tune the position adjustment plate 10, causing a change in the position of the metal terminal block inside the electrode box 11 and the sliding of the electrode, resulting in a change in the current rotation path, determining the relative position of the metal terminal block, and fixing it by the push rod on the electric cylinder; the positive and negative electrodes are symmetrically distributed relative to the workpiece 14. When the rolling speed remains constant, consider the temperature change of the workpiece 14 under different electrode spacings as follows: Figure 13 As shown, the maximum temperature on the workpiece increases rapidly with the increase in the distance between the electrode and the workpiece 14. An increase in the distance between the electrode and the workpiece 14 of no more than 10 mm will result in an additional temperature rise of hundreds of degrees Celsius on the workpiece.

[0108] S8. According to steps S1-S7, with the assistance of current, the rolling assembly rolls the workpiece 14. Since the current simultaneously provides appropriate electric heating to the rolls, a composite forming process of warm rolling and electroplastic rolling of the workpiece is realized.

[0109] Therefore, the plate and strip electroplastic rolling device and rolling method proposed in this technical solution are based on the theoretical research results of electroplastic rolling and warm rolling of metals, and are modified on the basis of existing traditional plate and strip rolling mills. The positive and negative electrodes are respectively set on the upper side of the mill inlet and the lower side of the mill outlet, and respectively make sliding friction contact with the surfaces of the upper and lower rolls, thereby minimizing the resistance of the current loop and effectively introducing the current into the plastic deformation zone of the metal rolling. By adjusting the power supply current parameters and the relative position of the electrodes and the rolls, the magnitude and distribution of the current in the loop are controlled, realizing the combination of electroplastic rolling and warm rolling, and achieving the purpose of improving the plasticity of the metal rolled product and improving the mechanical properties of the rolled product.

[0110] Compared with existing technologies, this technical solution has the following advantages:

[0111] 1. Based on the thermal activation theory of dislocation slip, this scheme derives the essence of how current improves the plasticity of metals. That is, during the pulse current action time, the current causes a change in the strain rate of the tensile specimen, which will inevitably promote dislocation slip. Macroscopically, this is manifested as a reduction in metal flow stress and an increase in plasticity.

[0112] 2. This solution comprehensively utilizes the electroplastic and electrothermal effects of metals, improving the metal's plasticity and reducing deformation resistance. Simultaneously, the special electrode structure suppresses edge cracking during rolling and can reduce the need for annealing during the forming process, thus improving the physical properties of the rolled product. It is particularly suitable for the rolling process of difficult-to-form metal strips.

[0113] 3. The roll in this scheme consists of a roll sleeve and a roll core, with an insulating layer between them. The electrodes are directly placed on the surface of the roll sleeve, effectively introducing current into the plastic deformation zone of the workpiece, shortening the path of the entire current loop, reducing the resistance of the entire current loop, and also allowing for appropriate electric heating of the roll. This enables the simultaneous warm rolling and electroplastic rolling of the metal strip. Furthermore, by adjusting the current parameters and the position of the electrodes relative to the roll, the current distribution and electrothermal distribution in the plastic deformation zone of the roll and the metal strip can be controlled. This design offers strong controllability, simple operation, and suitability for actual industrial production.

[0114] 4. This solution uses a pressure sensor to set the output pressure of the electric cylinder push rod, ensuring constant pressure on the metal terminal block and electrode. This enables stable contact between the electrode and the roll through sliding friction and automatic compensation for electrode wear, thus ensuring the stability of the contact resistance of the auxiliary current circuit.

[0115] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0116] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A sheet metal strip electrostatic plastic rolling apparatus, characterized in that, include: frame; The rolling assembly includes a first roll and a second roll rotatably mounted on the frame, with the area between the first roll and the second roll forming the workpiece; The current application assembly includes a positive electrode and a negative electrode. The positive electrode is mounted on the inlet side of the forming zone of the workpiece via a positive electrode mounting mechanism. The positive electrode makes slidable contact with a portion of a first roll near the forming zone. The end face of the positive electrode for contacting the first roll is a curved surface adapted to the outer contour of the first roll. The negative electrode is mounted on the outlet side of the forming zone via a negative electrode mounting mechanism. The negative electrode makes slidable contact with a second roll near the forming zone. The end face of the negative electrode for contacting the second roll is a curved surface adapted to the outer contour of the first roll. The contact end face is a curved surface adapted to the outer contour of the second roll; the positive electrode includes a positive electrode block one and a positive electrode block two, which are connected by an insulating block; the contact positions of the positive electrode block one and the positive electrode block two with the first roll correspond to the two side edges of the workpiece; the negative electrode includes a negative electrode block one and a negative electrode block two, which are connected by an insulating block; the contact positions of the negative electrode block one and the negative electrode block two with the second roll correspond to the two side edges of the workpiece. The positive electrode is used to connect to the positive terminal of the power supply through conductive structure one, and the negative electrode is used to connect to the negative terminal of the power supply through conductive structure two, so as to form a current loop between the positive electrode, the first roll, the plastic deformation zone of the workpiece, the second roll and the negative electrode, and apply current to the plastic deformation zone of the workpiece.

2. The sheet metal electroplastic rolling apparatus according to claim 1, characterized in that, The first roll is located directly above the second roll.

3. The sheet metal electroplastic rolling apparatus according to claim 1, characterized in that, The end face of the positive electrode that contacts the first roll is a continuous curved surface extending along the axial direction of the first roll. The end face of the negative electrode that contacts the second roll is a continuous curved surface extending along the axial direction of the second roll.

4. The sheet metal electroplastic rolling apparatus according to claim 1, characterized in that, The positive electrode mounting mechanism includes a position adjustment plate, which is movably connected to the frame to adjust the posture of the positive electrode relative to the first roll; An electrode box is connected to the position adjustment plate. The electrode box is provided with a slide rail that matches the contour of the positive electrode, and the positive electrode is slidably installed in the slide rail. An electrode pushing mechanism is provided on the position adjusting plate, and the electrode pushing mechanism is used to press the positive electrode onto the first roller. A pressure sensor is mounted on the electrode pushing mechanism to detect the pushing force exerted by the electrode pushing mechanism on the positive electrode. The structure of the negative electrode mounting mechanism is exactly the same as that of the positive electrode mounting mechanism.

5. The sheet metal electroplastic rolling apparatus according to claim 4, characterized in that, The conductive structure is a metal terminal block with a circular hole for connecting the circuit. The metal terminal block is slidably installed in the electrode box and located between the electrode pushing mechanism and the positive electrode, so that the electrode pushing mechanism can press the metal terminal block onto the positive electrode. The structure of the second conductive structure is exactly the same as that of the first conductive structure.

6. The sheet metal electroplastic rolling apparatus according to claim 1 or 2, characterized in that, The first roll includes a roll sleeve, a roll core, and an insulating sleeve. The roll sleeve is sleeved outside the roll core, and the insulating sleeve is disposed between the roll sleeve and the roll core. The structure of the second roll is exactly the same as that of the first roll.

7. A method for electroplastic rolling of sheet metal, implemented using the electroplastic rolling apparatus as described in any one of claims 1 to 6, characterized in that, Including the following steps: S1. Make the positive electrode in close contact with the first roll located on the inlet side of the forming zone of the rolled piece, and make the negative electrode in close contact with the second roll located on the outlet side of the forming zone of the rolled piece; S2. The positive electrode is connected to the positive terminal of the power supply through a conductive structure one, and the negative electrode is connected to the negative terminal of the power supply through a conductive structure two, so that the positive electrode, the first roll, the plastic deformation zone of the workpiece, the second roll, and the negative electrode form a current loop, so as to apply current to the plastic deformation zone of the workpiece when the first roll and the second roll ...

8. The method for electroplastic rolling of sheet metal according to claim 7, characterized in that, Before step S1, the following steps are also included: S0, based on the physical parameters of the workpiece, the amount of plastic deformation of the workpiece during rolling, and the influence of current-assisted metal plastic forming on the physical properties of the workpiece, the applied current parameters are set, and the corresponding current distribution is selected within the adjustment range of the current density value to simulate the distribution law of the current inside the workpiece when the electroplastic effect occurs, and the current density value of the plastic deformation zone of the workpiece is determined.

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