A strip-tensioning asynchronous electric plastic rolling mill and process suitable for hard-to-deform alloy foil strips

Abstract

The present invention provides a strip-tensioning asynchronous electric-plastic rolling mill and a process suitable for hard-to-deform alloy foil strips, and relates to the field of automation of plastic processing equipment. The strip-tensioning asynchronous electric-plastic rolling mill comprises an electric-plastic rolling mill body, the stepless differential electric rolling roller is a different-diameter structure, an alloy foil strip is arranged between the conductive roller and the electric rolling roller, the strip-tensioning conductive roller, the stepless differential electric rolling roller and the alloy foil strip form an energized circuit, the strip-tensioning conductive roller is a positive electrode of an electric pulse, the stepless differential electric rolling roller is a negative electrode of an electric pulse, and a large tension is applied to the strip-tensioning conductive roller by two winding devices. The present invention couples the mechanical relationship of strip-tensioning asynchronous rolling and the fine-grained modification mechanism of the electric-plastic effect, utilizes the ultra-fast online dynamic recrystallization behavior of electric pulses, performs real-time plasticization modification of hard-to-deform alloy foil strips with a large width-to-thickness ratio, realizes the basic process system of strip-tensioning asynchronous electric rolling, and breaks through the production bottleneck of hard-to-deform alloy foil strips with a large width-to-thickness ratio.

Description

Technical Field

[0001] The present invention relates to the field of automation of plastic processing equipment, and in particular to a strip-tensioning asynchronous electric plastic rolling mill and process suitable for hard-to-deform alloy foil strips. Background Art

[0002] With the rapid development of high-performance alloys, they are widely used in various industries due to their excellent performance. Among them, alloy foils with a thickness of less than 0.1 mm are indispensable raw materials for many flexible circuits, folding screens, micro-equipment and other fields. It is urgent to develop corresponding plasticization theories and forming technologies to improve the microstructure and shape indicators of large width-to-thickness ratio foils, which can not only expand the application field of alloy foils, but also significantly improve the production efficiency and processing cost of alloy foils. However, due to the limitations of the alloy's own characteristics, plastic forming theory, rolling equipment and measurement and control instruments, alloy foils have poor forming efficiency, low production efficiency, small width-to-thickness ratio, difficult to control microstructure and performance, and low shape and size accuracy, resulting in expensive processing costs and limited scope of application.

[0003] Taking magnesium alloy foil as an example, most of the traditional processing methods are mainly hot extrusion, hot rolling and warm rolling. On the one hand, plasticity is increased by shearing to promote sliding of cylindrical and conical surfaces, and on the other hand, plasticity is improved by increasing the deformation temperature and utilizing the fine grain effect of dynamic recrystallization. In terms of forming theory, it is a common understanding to use thermal-mechanical coupling to adjust the orientation texture or organizational properties, with the aim of changing the plasticity of high-brittle and difficult-to-deform magnesium foil or other high-hardness and high-brittle alloy materials. However, the current common problem is that hot extrusion has high requirements for die dimensional accuracy and wear resistance, and also has strict requirements for the deformation temperature curve. The temperature range is between 225℃ and 450℃. Too low temperature leads to twins, shear bands and mixed crystal structures, which are easy to induce edge cracks, surface cracks or fracture defects. Too high temperature can easily lead to excessive grain growth, performance degradation and severe surface oxidation. In addition, under the action of no tension, the rolling process of large width-to-thickness ratio alloy foil is extremely unstable, easy to lose stability and wave, resulting in low shape and size accuracy and easy wrinkling on the surface. In addition, there are two heating methods: one is traditional furnace heating and heat treatment, followed by rolling on a machine; the other is online induction heating to increase the temperature. However, both heating methods have obvious defects that cannot be solved. First, the temperature of the foil strip heated in the furnace drops too quickly after it leaves the furnace. The thinner the rolled piece, the faster the heat dissipation, and the greater the lateral temperature difference, resulting in uneven organization and deformation. Second, induction heating is not suitable for wide bands, and there will still be a sharp temperature drop at the roll gap, resulting in the actual deformation temperature not meeting the optimal forming temperature. Excessive preheating temperature will lead to severe surface oxidation, affecting the surface quality after rolling.

[0004] Based on the above problems, it is necessary to design an efficient rolling equipment suitable for large width-to-thickness ratio foil strips according to the microstructure characteristics and forming mechanism of the foil strips. On the basis of the traditional rolling process, the rolling mill structure with the synergistic effect of asynchronous rolling and electro-plastic effect is designed, and the tension system of foil strip rolling is reasonably designed to achieve stable and high-precision rolling of large width-to-thickness ratio foil strips. Summary of the invention

[0005] In view of this, the purpose of the present invention is to propose a strip tensioning asynchronous electro-plastic rolling mill and process suitable for difficult-to-deform alloy foil strips. The basic structure of the rolling mill is designed by means of asynchronous rolling and electro-plastic effect synergistically, and tension is applied in combination with front and rear coiling to change the force mode or deformation law of the foil strip at the roll gap. At the same time, the electro-plastic effect is used to realize online dynamic recrystallization of the magnesium foil, obtain the best uniform fine-grained structure, and meet the requirements of efficient rolling process for foil strips with a large width-to-thickness ratio.

[0006] The technical means adopted by the present invention are as follows:

[0007] An asynchronous electric plastic rolling mill for strips of hard-to-deform alloy foil, comprising an electric plastic rolling mill body, and also comprising:

[0008] A pair of stepless differential electric rollers, the stepless differential electric rollers are arranged in the body of the electric plastic rolling mill, the stepless differential electric rollers are of different diameter structures, the stepless differential electric rollers can be steplessly adjusted in speed, the stepless differential electric rollers include an upper electric roller and a lower electric roller, the upper electric roller is connected to an upper support roller, the lower electric roller is connected to a lower support roller, the stepless differential electric rollers cooperate with a winding device and a belt tensioning conductive roller to reduce the uneven deformation of the upper and lower surfaces of the foil strip, and change the force direction and shear stress of the foil strip in the roller gap deformation zone;

[0009] Two conductive belt rollers, the two conductive belt rollers are respectively arranged at the entrance and exit of the electric plastic rolling mill body, an alloy foil strip is arranged between the conductive belt rollers and the electric rolling rollers, the conductive belt rollers, the stepless differential electric rolling rollers and the alloy foil strip form an electric circuit, the conductive belt rollers are the positive electrodes of the electric pulses, the stepless differential electric rolling rollers are the negative electrodes of the electric pulses, the conductive belt rollers are applied with a large tension by two winding devices, the magnitude of the large tension is more than 50% of the deformation resistance of the alloy foil strip, the two winding devices are respectively arranged at the entrance and exit of the electric plastic rolling mill body, and the winding devices are in contact with the alloy foil strip;

[0010] An adjustable pulse power supply provides high-energy pulse power to the electric roller and the conductive roller. During the rolling process, the conductive roller in front of the machine is automatically switched to be powered according to the rolling direction to complete the power pretreatment of the foil strip.

[0011] A Joule heat temperature control system, comprising a thermal imager, a thermocouple, an industrial computer and a temperature control system.

[0012] Furthermore, the speed matching relationship of the stepless differential electric roller is:

[0013] When the upper support roller and the lower support roller have the same roller diameter but different rotation speeds, the rotation speed ratio between the upper support roller and the lower support roller is:

[0014] η f =ω 上支 / ω 下支

[0015] When the speeds of the upper support roller and the lower support roller are different, and the diameters of the upper electric roller and the lower electric roller are different, the speed ratio of the upper support roller and the lower support roller is:

[0016] η f =(ω 上支 R 下工 ) / (ω 下支 R 上工 )

[0017] Where: 上支 is the upper support roller speed, ω 下工 is the rotation speed of the lower support roller, R 上工 R is the diameter of the electric roller, 下工 is the diameter of the lower electric rolling roller.

[0018] Furthermore, the rotation speed ratio of the upper support roller and the lower support roller ranges from 0.75 to 1.35.

[0019] Furthermore, the Joule heat temperature control system is used to feedback the electric field distribution, and set the voltage, pulse width and frequency of the high-energy pulse according to the rolling force, rolling speed and width-to-thickness ratio of the foil strip to obtain a uniform electric field distribution, so that it matches the deformation parameters, improves the plasticity of the difficult-to-deform foil strip, and completes the reversible electric rolling process of the front and rear strip tension.

[0020] Furthermore, normally, the tension of the winding device at the outlet is greater than the tension of the winding device at the inlet. When the alloy foil strip is a high-brittle foil strip, the tension of the winding device at the inlet is greater than the tension of the winding device at the outlet.

[0021] The present invention also provides a belt tension asynchronous electroplastic process applicable to a hard-to-deform alloy foil strip, which is implemented based on any of the above belt tension asynchronous electroplastic rolling mills and includes the following steps:

[0022] At the initial rolling stage, the tension is established to obtain a stable rolling condition, and the inlet tension of the inlet coiling device is set to be greater than the outlet tension of the outlet coiling device;

[0023] Start the strip tension asynchronous electro-plastic rolling mill at low speed, turn on the pulse power supply at the same time, energize the foil strip in the section through the conductive roller and the electric rolling roller to implement the electro-plastic effect, perform online dynamic recrystallization and rapid recovery, realize ultra-fast low-temperature plasticization of the foil strip, and change the initial grain size and deformation resistance;

[0024] The strip asynchronous electric rolling is accelerated after being stabilized at a low speed, and the current density of the pulse power supply is adaptively adjusted according to the rolling speed to keep the foil strip at a constant temperature and constant current;

[0025] Set the outlet tension greater than the inlet tension, and put the thickness automatic control system, plate shape automatic control system and temperature automatic control system into closed-loop control to obtain the best organizational performance and shape and size accuracy;

[0026] When approaching the tail-flick stage, the electric pulse is processed in reverse, so that the electric pulse can adjust the pulse current adaptively;

[0027] Cut off the power in advance before the drift stops;

[0028] Obtain a large width-to-thickness ratio alloy foil strip with good plate shape.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] The present invention adopts an asynchronous rolling method combining different speed transmission and different diameters of electric rolling rollers to achieve stepless differential rolling, and breaks through the minimum rollable thickness limit by utilizing asynchronous rolling to enhance shear force; on this basis, the matching relationship of the front and rear large tensions is coordinated to change the three-dimensional stress state of the deformation zone, and mechanical conditions are utilized to enable the difficult-to-deform foil to obtain a better soft orientation plasticization mechanism; the pulse width and frequency of the high-energy pulse are adaptively adjusted to adapt to the rolling speed of foils with different width-to-thickness ratios, constant current and constant temperature conditions are ensured, and a stable strip tension asynchronous electric rolling process is obtained, and an ultra-fast dynamic recrystallization mechanism is utilized to meet the conditions for fine grain modification, and the mechanical plasticization relationship of the coordinated strip tension asynchronous is coordinated, and at the same time, the AGC, AFC and ATC closed-loop measurement and control systems are combined to achieve the online shape control index requirements of the large width-to-thickness ratio foil. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1 It is a schematic diagram of the belt tension asynchronous electric plastic rolling mill of the present invention.

[0033] Figure 2 This is the basic process of the asynchronous electric-rolling coupling model of the present invention.

[0034] Figure 3 This is the belt tension asynchronous electric rolling control method of the present invention.

[0035] Figure 4 It is a schematic diagram of the asynchronous electric plastic rolling mechanism of the present invention.

[0036] In the figure: 1. high-energy pulse power supply; 2. support roller; 3. electric rolling roller; 4. conductive roller; 5. plate shape meter; 6. high-tension winding device; 7. temperature meter; 8. pressure-down closed-loop system; 9. temperature closed-loop system; 10. plate shape closed-loop system. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0038] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0039] like Figure 1-4 As shown, the present invention provides a strip tension asynchronous electric plastic rolling mill suitable for difficult-to-deform alloy foil strips, including a different speed + different diameter structure, a conductive roller 4 and an electric rolling roller 3, a high-precision pulse power supply 1, an insulating closed loop, front and rear large tension settings and a four-roller or six-roller rolling mill body (roller system and frame), hydraulic automatic control 8 (AGC + thickness gauge), plate shape automatic control 10 (AFC + plate shape meter), and temperature automatic control 9 (ATC + temperature meter).

[0040] First, the different speed + different diameter structure uses dual frequency conversion motors to drive electric rollers 3 of different diameters, or drives electric rollers 3 of different diameters through the same diameter support roller 2, so as to realize a stable asynchronous rolling process with stepless speed change. The speeds of the support rollers 2 after the upper and lower motors are set to be ω上支 and ω 下支 , the diameter of the support roller 2 is R 支 The roller diameters of the electric rolling rollers 3 are R 上工 and R 下工 , then the actual electric roller 3 speed ω 上工 and ω 下工 They are

[0041] ω 上工 =ω 上支 R 支 / R 上工 ,ω 下工 =ω 下支 R 支 / R 下工 (1)

[0042] When the speeds of the upper and lower support rollers 2 are the same, the asynchronous ratio is only the speed ratio η caused by the roller diameter difference of the electric rolling roller 3. b for

[0043] η b =R 下工 / R 上工 (2)

[0044] If the upper and lower support rollers 2 have the same roller diameter, and the upper and lower electric rollers 3 have the same roller diameter, asynchronous rolling can also be achieved by using the speed ratio of the support roller 2. In this case, the speed ratio is expressed as

[0045] η f =ω 上支 / ω 下支 (3)

[0046] When the rotation speeds of the upper and lower support rollers 2 are different, and the diameters of the upper and lower electric rollers 3 are different, it is necessary to add the additional speed ratio caused by the upper and lower support rollers 2 on the basis of the speed ratio caused by the diameter difference of the electric roller 3. The total speed ratio η f for

[0047] η f =(ω 上支 R 下工 ) / (ω 下支 R 上工 ) (4)

[0048] In general, according to the rolling requirements, the online speed of the upper and lower electric rolling rollers can be matched in real time, accelerated and decelerated synchronously, and the average speed ratio is controlled between 0.75 and 1.35. The overall principle is to obtain sufficient shearing capacity and ensure the stability of the rolling process.

[0049] Secondly, the conductive circuit includes the conductive roller 4 (positive electrode), the electric rolling roller 3 (negative electrode) and the foil strip therebetween. After connecting the high-energy pulse power supply 1, an energized circuit is formed. The foil strip is subjected to the electroplastic effect by using high-frequency and high-peak current, and the online dynamic recrystallization and rapid recovery are performed to achieve ultra-fast low-temperature plasticization of the foil strip. In the asynchronous electric rolling process, reversible rolling is performed back and forth. The conductive roller 4 is respectively set at the entrance / exit of the rolling mill. When the entrance / exit is switched, the conductive roller 4 at the entrance and the electric rolling roller 3 are always ensured to form an energized circuit by using manual or automatic mode. In addition, outside the energized circuit, insulation isolation is set to the maximum extent to form an absolutely reliable closed loop circuit to reduce leakage or voltage and current loss. When the high-energy pulse power supply 1 is energized, the conductive roller 4 and the electric rolling roller 3 are used to continuously energize the magnesium foil in the middle section at high frequency, so that the Joule heat effect is used to obtain the ideal deformation temperature, and the pure electro-induced effect (electron wind) is used to obtain additional slip plasticization conditions.

[0050] One point that needs to be emphasized is that in order to prevent leakage during the rolling process, on the one hand, insulation treatment is carried out outside the power-on circuit to form a closed loop, so as to maximize the high voltage and high pulse at the roll gap position; on the other hand, leakage protection is carried out to form a ground loop to avoid personal operating errors.

[0051] In addition, the plasticization conditions are mainly the mechanical relationship of the coordinated belt tension asynchronous rolling and the mechanism of the electroplastic effect to obtain the best plastic conditions. In order to improve the plastic deformation and the shape and size control accuracy of the rolled foil, a large tension winding device 6 is applied before and after the rolling mill. Combined with the stress conditions of the asynchronous rolling deformation zone and the mechanical properties of the foil, the optimal front and rear tension values ​​are set to ensure a stable asynchronous electric rolling process. Assume that the front and rear tensions (the inlet is the rear tension, the outlet is the front tension, and the reversible process is switched according to the rolling direction) are T1 and T0 respectively, and the deformation resistance considering the electroplastic effect is k s , the reduction rate is λ, the exit rolling speed is υ1, then the rolling force P is expressed as

[0052]

[0053] In the formula is the average width, is the average rolling pressure in the deformation zone, p xUnit width rolling pressure, x is the coordinate of the contact arc length position point, l' is the contact arc length considering elastic flattening, and F is the area of ​​the deformation zone. Considering that the foil strip is difficult to deform and easy to become unstable and wave, usually, the front tension is set to be greater than the rear tension to improve the stability of the rolling process, promote uniform deformation of the foil strip, obtain a good export plate shape, and help reduce the rolling force or main motor load. However, for highly brittle foil strips, in order to avoid edge cracks or strip breaks, and to facilitate biting and not deviating, the rear tension will be greater than the front tension to ensure stable rolling conditions in the initial stage. For example, this mode can be used for rolling in the head and tail acceleration and deceleration stages.

[0054] Finally, in order to improve the dimensional accuracy and production stability of foil rolling, it is necessary to combine tension meters, thermometers, AGC, AFC and thickness gauges to implement automatic closed-loop control of the tension, temperature, plate shape and thickness of large width-to-thickness ratio foils, improve the shape and size control accuracy, control good organizational performance online, and continuously meet the process requirements of high-speed asynchronous electric rolling online.

[0055] The purpose of the present invention is to provide a strip tensioning asynchronous electro-plastic rolling mill suitable for hard-to-deform alloy foil strips. By designing the synergistic mechanism of front and rear strip tensioning + asynchronous rolling + electro-plastic effect, the elastic deformation model of the roller system and the metal model are coupled and calculated to obtain the internal metal velocity field, position field, temperature field, stress-strain field and lateral thickness difference change of the large width-to-thickness ratio alloy foil strip. The mechanical relationship is used to realize the softening of the hard orientation of the magnesium foil after rolling, and the Joule heating effect and pure electro-induced effect (electron wind) of electro-plasticity are used to realize rapid dynamic recrystallization, thereby realizing rapid online plasticization modification of the hard-to-deform foil strip, and facilitating the continuous thinning and shape (shape and performance) control of the large width-to-thickness ratio alloy foil strip.

[0056] In order to achieve the above-mentioned purpose, the following scheme is adopted: the asynchronous electric plastic rolling mill for strip tensioning of difficult-to-deform alloy foil strips described in the present invention first utilizes the basic structure of a two-roller, four-roller or six-roller or even an eight-roller, sixteen-roller and twenty-roller rolling mill to drive the double rollers at different speeds to obtain stepless differential speed change, and at the same time sets a fixed diameter ratio of the upper and lower electric rolling rollers (the rollers can be ground according to the fixed asynchronous ratio to obtain a suitable upper and lower roller diameter ratio). During use, according to process requirements, a wide range of stepless differential rolling with coordinated speed and diameter differences is carried out; secondly, conductive rollers 3 are respectively arranged before and after the rolling mill as positive electrodes, and a single electric rolling roller or the upper and lower electric rolling rollers are simultaneously used as negative electrodes. During the rolling process, the conductive roller 4 before rolling is connected according to the rolling direction to form a closed loop, and a high-energy pulse power supply 1 is used to apply high-frequency pulses For the impulse current, insulation treatment is done outside the loop to prevent voltage and current leakage from reducing the electro-plastic effect. At the same time, good grounding and power-off protection are set to ensure personal safety to the maximum extent. In addition, a plate shape meter 5 and a temperature meter 7 are respectively set before and after the machine to measure the plate shape state and transient temperature before and after rolling, and indirectly feedback the control effect of asynchronous electro-plasticity or the state after rolling. In the actual rolling process, different tensions are applied by front and rear coiling, and the process is set according to the rolling state or the stability of the rolled piece. At the same time, the stress state of the deformation zone is significantly changed to make it meet the mechanical plasticization conditions of soft orientation, and to a certain extent, the rolling force and the elastic flattening and deflection of the roller are greatly reduced, so as to obtain a relatively good load roll gap shape, which is conducive to adjusting the lateral thickness difference change and finally obtaining a good plate shape.

[0057] like Figure 1 As shown in the figure, the core of the strip tension asynchronous electric rolling mill lies in the synergistic plasticization effect of large front and rear tension, asynchronous rolling and electro-plastic effect. Firstly, the rolling force is reduced by large front and rear tension to obtain good three-dimensional force conditions. On the one hand, the elastic flattening and flexural deformation of the rollers are weakened to obtain a good cross-sectional shape or transverse thickness difference of the foil strip, which is beneficial to the plate shape control. On the other hand, the hard orientation of the foil strip in the deformation zone is transformed to a soft orientation, and good deformation conditions are obtained, which is beneficial to obtain a stable rolling process. Secondly, the asynchronous rolling of the foil strip is realized by using the differential ratio of dual-drive speed difference and electric roller diameter difference. By enhancing the shearing capacity, the minimum rollable thickness of synchronous rolling is cancelled, which is beneficial to obtain continuous limit thinning conditions and meet the plasticization conditions of mechanical relations. On the basis of strip tension asynchronous rolling, electro-plasticity is used to obtain ultra-fast online dynamic recrystallization conditions, which not only uses the internal heat source property of Joule heat to quickly heat the magnesium foil to reach the ideal deformation temperature range, but also uses the pure electro-induced effect (electron wind) to obtain good low-temperature plasticity, thereby avoiding excessive grain growth, mixed crystal structure and severe surface oxidation of the foil strip. It is obvious that the rolling characteristics of asynchronous electric rolling can improve the performance and shape control accuracy of large width-to-thickness ratio difficult-to-deform alloy foil from two aspects: mechanical relationship and microstructure. This is something that has not been considered in the past and is worthy of further theoretical research and industrial testing.

[0058] Figure 2 The basic process of asynchronous electric rolling of strip is shown. In the regulation process, in order to meet the precise control of performance and shape, a high-precision thickness automatic control AGC system, a plate shape automatic control AFC system and a temperature automatic control ATC system (electric pulse Joule heat closed-loop control, electric field distribution through temperature feedback) are configured, which largely realizes the mechanical properties of large width-to-thickness ratio foil strips (plasticity, toughness, elongation, strength and stiffness are controlled by grains and textures), shape and size (plate shape and plate convexity are controlled by transverse thickness difference), and surface quality (surface roughness is controlled by friction peaks, and surface oxidation degree is controlled by temperature). In the entire calculation process, all parameters need to be substituted into the roller system elastic deformation model and metal coupling model, and synchronous calculations under the same working conditions are performed to obtain the best thermal-mechanical coupling conditions and organizational morphology to meet the process requirements of ultra-fast online plasticization modification. Based on the above rolling conditions, it can be ensured that each pass maintains good grain size, texture orientation and mechanical properties, thereby meeting the best forming process and realizing continuous rolling of large width-to-thickness ratio difficult-to-deform foil strips without intermediate annealing or heat treatment.

[0059] Figure 3 The process changes of strip tension asynchronous electric rolling in a single-pass rolling process are shown. In the initial rolling stage, in order to establish tension and obtain stable rolling conditions, the rear tension is set to be greater than the front tension. At the same time, after the rolling mill is started and tension is established, the pulse power supply is turned on, and the foil strip in the section is energized through the conductive roller and the electric rolling roller to change the initial grain size and deformation resistance; after obtaining low-speed stable strip tension asynchronous electric rolling, rapid acceleration begins, and at the same time, the current density of the pulse power supply is adaptively adjusted according to the rolling speed, so that the foil strip can maintain a constant temperature and constant current as much as possible to stabilize the deformation resistance or minimize its fluctuation. After reaching the set speed, the front tension is adjusted to be greater than the rear tension after maintaining constant temperature and current, so as to appropriately reduce the rolling force to improve the plate shape index. At this time, AGC+AFC+ATC closed-loop control is put into use to obtain the best organizational performance and shape and size accuracy; finally, in the stage of approaching tail-swinging, the electric pulse is processed in reverse to make it adaptively adjust the pulse current to match the rolling speed and the fluctuation of the mechanical parameters of the deformation zone, and when approaching tail-swinging, the power is cut off in time to avoid accidents caused by sudden circuit interruption.

[0060] Figure 4The synergistic relationship between the asynchronous rolling mechanical conditions in the deformation zone and the electric pulse plasticization effect is shown. First, for the asynchronous electric rolling process of the large width-to-thickness ratio foil, a stable uniform electric field condition is obtained through the conductive rollers and electric rolling rollers with good conductivity to ensure uniform rheological stress or deformation resistance, and the pulse width and frequency of the electric pulse are adjusted by the high-energy power supply to adaptively adjust the current duty cycle inside the foil, thereby changing the electric pulse plasticization effect of Joule heat and pure electro-induced effect in real time; secondly, the asynchronous rolling mechanical relationship of the deformation zone is utilized, and the shear effect is utilized to change the size and distribution of the rolling pressure with the coordinated tension on the one hand, and the force direction of the deformation zone on the other hand, so as to obtain the mechanical plasticization condition of soft orientation; under the synergistic effect of asynchronous rolling deformation and the comprehensive effect of electro-plasticity, the online dynamic recrystallization of the large width-to-thickness ratio foil is realized, and the grain size and texture orientation are changed rapidly, so as to ensure the good plasticity condition in the roller gap deformation zone, and finally obtain the best mechanical properties and shape indicators (plate shape, plate thickness and surface quality); repeat the above process, repeatedly change the rolling direction in a reversible manner, and finally meet the performance indicators and shape indicators of the established goals.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An asynchronous electric plastic rolling mill for strips of hard-to-deform alloy foil, comprising an electric plastic rolling mill body, characterized in that: Also includes: A pair of stepless differential electric rollers, the stepless differential electric rollers are arranged in the body of the electric plastic rolling mill, the stepless differential electric rollers are of different diameter structures, the stepless differential electric rollers can be steplessly adjusted in speed, the stepless differential electric rollers include an upper electric roller and a lower electric roller, the upper electric roller is connected to an upper support roller, the lower electric roller is connected to a lower support roller, the stepless differential electric rollers cooperate with a winding device and a belt tensioning conductive roller to reduce the uneven deformation of the upper and lower surfaces of the foil strip, and change the force direction and shear stress of the foil strip in the roller gap deformation zone; The speed matching relationship of the stepless differential electric roller is: When the upper support roller and the lower support roller have the same roller diameter but different rotation speeds, the rotation speed ratio between the upper support roller and the lower support roller is: η f = ω 上支 / ω 下支 When the speeds of the upper support roller and the lower support roller are different, and the diameters of the upper electric roller and the lower electric roller are different, the speed ratio of the upper support roller and the lower support roller is: η f =( ω 上支 R 下工 ) / ( ω 下支 R 上工 ) in: ω 上支 is the upper support roller speed, ω 下工 is the speed of the lower support roller, R 上工 is the diameter of the electric roller, R 下工 is the roller diameter of the lower electric roller; The speed ratio of the upper support roller and the lower support roller ranges from 0.75 to 1.35; Two belt tensioning conductive rollers, the two belt tensioning conductive rollers are respectively arranged at the entrance and exit of the electric plastic rolling mill body, an alloy foil strip is arranged between the conductive rollers and the electric rolling rollers, the belt tensioning conductive rollers, the stepless differential electric rolling rollers and the alloy foil strip form an electric circuit, the belt tensioning conductive rollers are the positive electrodes of the electric pulses, the stepless differential electric rolling rollers are the negative electrodes of the electric pulses, the belt tensioning conductive rollers are applied with a large tension by two winding devices, the magnitude of the large tension is more than 50% of the deformation resistance of the alloy foil strip, the two winding devices are respectively arranged at the entrance and exit of the electric plastic rolling mill body, and the winding devices are in contact with the alloy foil strip; An adjustable pulse power supply provides high-energy pulse power to the electric roller and the conductive roller. During the rolling process, the conductive roller in front of the machine is automatically switched to be powered according to the rolling direction to complete the power pretreatment of the foil strip. A Joule heat temperature control system, which includes a thermal imager, a thermocouple, an industrial computer and a temperature control system; the Joule heat temperature control system is used to feedback the electric field distribution, set the voltage, pulse width and frequency of the high-energy pulse according to the rolling force, rolling speed and the width-to-thickness ratio of the foil strip, obtain a uniform electric field distribution, match it with the deformation parameters, improve the plasticity of the difficult-to-deform foil strip, and complete the reversible electric rolling process of the front and rear strip tension; Normally, the tension of the winding device at the outlet is greater than the tension of the winding device at the inlet. When the alloy foil strip is a high-brittle foil strip, the tension of the winding device at the inlet is greater than the tension of the winding device at the outlet.

2. A strip-tension asynchronous electroplastic process suitable for hard-to-deform alloy foil strips, implemented based on the strip-tension asynchronous electroplastic rolling mill according to claim 1, characterized in that: The steps include: At the initial rolling stage, the tension is established to obtain a stable rolling condition, and the inlet tension of the inlet coiling device is set to be greater than the outlet tension of the outlet coiling device; Start the strip tension asynchronous electro-plastic rolling mill at low speed, turn on the pulse power supply at the same time, energize the foil strip in the section through the conductive roller and the electric rolling roller to implement the electro-plastic effect, perform online dynamic recrystallization and rapid recovery, realize ultra-fast low-temperature plasticization of the foil strip, and change the initial grain size and deformation resistance; The strip asynchronous electric rolling is accelerated after being stabilized at a low speed, and the current density of the pulse power supply is adaptively adjusted according to the rolling speed to keep the foil strip at a constant temperature and constant current; Set the outlet tension greater than the inlet tension, and put the thickness automatic control system, plate shape automatic control system and temperature automatic control system into closed-loop control to obtain the best organizational performance and shape and size accuracy; When approaching the tail-flick stage, the electric pulse is processed in reverse, so that the electric pulse can adjust the pulse current adaptively; Cut off the power in advance before the drift stops; Obtain a large width-to-thickness ratio alloy foil strip with good plate shape.

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