Rolling mill vibration control method based on mechanism analysis model

Abstract

The invention provides a rolling mill vibration control method based on a mechanism analysis model, and belongs to the technical field of vibration control in the metal rolling process, and the method comprises the steps: determining energy transmission paths of a rolling mill vibration system, calculating the energy value of each energy transmission path, and calculating the energy value of each energy transmission path according to the energy value of each energy transmission path; the energy value of vibration is calculated through the law of conservation of energy; the energy value of vibration is used as a boundary condition for solving a kinetic equation, and a mechanism expression of vibration displacement is obtained through calculation; performing process analysis on the mechanism expression of the vibration displacement to obtain rolling parameter adjustment strategies in different states; and rolling mill vibration control is conducted on a rolling mill vibration system according to the rolling parameter adjusting strategies in the different states. According to the control method, the product quality of the strip steel is improved, and the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of vibration control in a metal rolling process, and in particular relates to a rolling mill vibration control method based on a mechanism analysis model. Background Art

[0002] During the rolling process, the vibration of the rolling mill directly causes the thickness fluctuation of the strip, affecting the product accuracy of the strip; when the vibration is severe, it may even cause strip or roll breakage accidents, causing economic losses and reducing production efficiency. Through on-site investigation, it was found that the cold rolling vibration phenomenon often occurs in the last pass of the continuous rolling mill and occurs in the form of triple frequency vibration. The rolling mill vibration phenomenon has also become a key factor restricting the improvement of product quality and is a key problem that urgently needs to be solved in the rolling field.

[0003] At present, the research on vibration relies on numerical simulation or data-driven methods, which only focus on analyzing vibration under specific working conditions, lack the universal applicability of the model, and fail to establish a clear mathematical and physical relationship between rolling process parameters and vibration. In addition, they cannot obtain the displacement function expression of vibration, so it is difficult to develop an effective vibration suppression strategy. This is the main reason why there is no better research on vibration reduction strategies. Some researchers also solve the equations by assuming boundary conditions, and the calculation results do not have physical meaning related to the rolling process and cannot reflect the actual rolling process. In addition, the main means of on-site vibration suppression is to reduce the rolling speed, which greatly reduces production efficiency. Therefore, it is necessary to propose a vibration suppression rolling strategy for different working conditions. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present application proposes a rolling mill vibration control method based on a mechanism analysis model. The main purpose of the control method of the present application is to reveal the root cause of the rolling mill vibration and provide vibration suppression strategies under different working conditions.

[0005] This application proposes a rolling mill vibration control method based on a mechanism analysis model, comprising:

[0006] Determine the energy transmission path of the rolling mill vibration system, calculate the energy value of each energy transmission path, and calculate the energy value of the vibration according to the energy value of each energy transmission path by the law of conservation of energy;

[0007] The energy value of the vibration is used as the boundary condition for solving the dynamic equation to calculate the mechanism expression of the vibration displacement;

[0008] The mechanism expression of vibration displacement is analyzed to obtain the rolling parameter adjustment strategy under different conditions.

[0009] The rolling mill vibration system is subjected to rolling mill vibration control using the rolling parameter adjustment strategy under the different states.

[0010] The calculating the energy value of each energy transmission path includes:

[0011] Calculate the work done by the rollers in pressing down;

[0012] Calculate the energy of work roll rotation;

[0013] Calculate the plastic deformation work of the strip;

[0014] Calculate the frictional heat generated during the rolling process.

[0015] The step of calculating the energy value of the vibration according to the energy value of each energy transmission path by using the law of conservation of energy includes:

[0016] The energy value of the vibration is calculated by the law of conservation of energy based on the work done by the rollers, the energy of the working rollers rotating, the work of plastic deformation of the strip, and the friction heat generated during the rolling process.

[0017] The energy value of the vibration is calculated as follows:

[0018] W z =(W F +W J )-(W i +W f )

[0019] Among them, W z is the energy value of the vibration, W F is the work done by the roller pressing down, W J is the energy of the working roll rotation, W i is the plastic deformation work of the strip, W f It is the friction heat generated during the rolling process.

[0020] The energy value of the vibration is used as the boundary condition for solving the dynamic equation to calculate the mechanism expression of the vibration displacement, including:

[0021] A mass-spring dynamic model is established for the upper working roll of the rolling mill vibration system, the intermediate roll is simplified as a point of concentrated mass, and the damping term between the intermediate roll and the working roll is ignored.

[0022] The energy value of the vibration is used as the boundary condition for solving the mass-spring dynamics model, and the mechanism expression of the vibration displacement is calculated.

[0023] The mass-spring dynamics model is calculated as follows:

[0024]

[0025] Among them, Δf is the fluctuation value of rolling force, M is the mass of working roll, K is the stiffness between rolls, and y is the vibration displacement.

[0026] The energy value of the vibration is used as the boundary condition for solving the mass-spring dynamics model to calculate the mechanism expression of the vibration displacement. The calculation process is as follows:

[0027] The mass-spring dynamics model is solved to obtain the solution, and the calculation formula is as follows:

[0028]

[0029] Among them, Δf is the fluctuation value of rolling force, M is the mass of working roll, K is the stiffness between rolls, y is the vibration displacement, C1 is the first coefficient, and C2 is the second coefficient;

[0030] The energy of the working roll vibration is calculated as follows:

[0031]

[0032] Among them, W 振动 is the energy of the working roll vibration, W 势能 is the potential energy of the working roll, W 动能 For the kinetic energy of work;

[0033] in,

[0034]

[0035] Where, v is the speed of the roller;

[0036] The energy value of the vibration is used as the boundary condition for solving the mass-spring dynamics model to obtain the equation, which is calculated as follows:

[0037]

[0038] When the time of starting the rolling roll is equal to 0, the vibration amplitude at this time is c=0, and the value of the first coefficient C1 and the value of the second coefficient C2 are obtained by solving the equation. The value of the first coefficient C1 and the value of the second coefficient C2 are substituted into the calculation formula of the solution result to obtain the mechanism expression of the vibration displacement;

[0039] The mechanism expression of the vibration displacement is calculated as follows:

[0040]

[0041] Among them, C1 is the first coefficient, C2 is the second coefficient, Δf is the fluctuation value of rolling force, M is the mass of working roll, K is the stiffness between rolls, t is the rolling time, h in is the strip entrance thickness, hout is the outlet thickness of the rolled strip, V out is the strip exit speed, V in is the strip inlet speed, h m is the thickness of the strip before rolling, W z is the energy generated by vibration, which is calculated by the energy conversion formula.

[0042] The process analysis of the mechanism expression of vibration displacement is performed to obtain the rolling parameter adjustment strategies under different states, including:

[0043] According to the mechanism expression of the vibration displacement, the influence of the change of input parameters on the vibration displacement is analyzed;

[0044] According to the influence of input parameter changes on vibration displacement and the mechanism expression of vibration displacement, the strategy to reduce vibration under different rolling conditions is obtained.

[0045] The step of analyzing the influence of the change of input parameters on the vibration displacement according to the mechanism expression of the vibration displacement includes:

[0046] Substituting the change of the strip steel inlet thickness into the mechanism expression of the vibration displacement, the influence of the change of the strip steel inlet thickness on the vibration displacement is obtained;

[0047] Substituting the reduced value of the friction coefficient into the mechanism expression of the vibration displacement, the influence of the reduced value of the friction coefficient on the vibration displacement is obtained.

[0048] According to the influence of the change of input parameters on the vibration displacement and the mechanism expression of the vibration displacement, the strategy of reducing vibration under different rolling conditions is obtained, including:

[0049] According to the influence of friction coefficient reduction on vibration displacement and the mechanism expression of vibration displacement, the relationship between friction coefficient and vibration displacement is obtained, and the first strategy to reduce vibration is given: when the friction coefficient continues to decrease, the purpose of reducing vibration displacement is achieved by increasing the rolling speed; the second strategy to reduce vibration is: when the friction coefficient continues to decrease, the purpose of reducing vibration displacement is achieved by reducing the rolling force or increasing the tension between the stands;

[0050] According to the influence of the change of strip entrance thickness on the vibration displacement and the mechanism expression of vibration displacement, the relationship between the strip entrance thickness and the rolling force and the tension between the frames is obtained. The first strategy to reduce vibration is given: when the strip entrance thickness changes, the rolling force value is adjusted by adjusting the pressure reduction, and the tension between the frames is adjusted.

[0051] Beneficial effects:

[0052] This application proposes a rolling mill vibration control method based on a mechanism analysis model, which reveals the mathematical and physical relationship between the rolling mill vibration phenomenon and the rolling parameters, establishes a mechanism expression of vibration displacement, and based on the mechanism model, can analyze the causes of rolling mill vibration analysis, can study the control methods for suppressing or reducing vibration under different working conditions, improve the product quality of strip steel, and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A flow chart of a rolling mill vibration control method based on a mechanism analysis model according to an embodiment of the present application;

[0054] Figure 2 A schematic diagram of the energy transfer path of the rolling mill vibration system provided in an embodiment of the present application;

[0055] Figure 3 A schematic diagram of a working roll mass-spring model according to an embodiment of the present application;

[0056] Figure 4 The influence of the thickness fluctuation of the strip steel entrance on the vibration displacement in the embodiment of the present application;

[0057] Figure 5 The curve showing the variation of the friction coefficient with the rolling mileage in the embodiment of the present application;

[0058] Figure 6 The curve showing the variation of vibration displacement with rolling mileage in the embodiment of the present application;

[0059] Figure 7 The influence of the friction coefficient and rolling speed on the vibration displacement of the embodiment of the present application;

[0060] Figure 8 The influence of the tensile stress on the vibration displacement before and after adjustment of the embodiment of the present application;

[0061] Fig. 9 The vibration displacement of the embodiment of the present application varies with the rolling force and the friction coefficient;

[0062] Fig.10 The vibration displacement of the embodiment of the present application varies with the rolling force and the inlet thickness;

[0063] Among them, 1-roller, 2-hydraulic pressing system, 3-motor transmission system, 4-strip steel, 5-frame. DETAILED DESCRIPTION

[0064] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0065] Example:

[0066] This application proposes a rolling mill vibration control method based on a mechanism analysis model, such as Figure 1 As shown, including:

[0067] Step S1: determining the energy transmission path of the rolling mill vibration system, calculating the energy value of each energy transmission path, and calculating the energy value of the vibration according to the energy value of each energy transmission path by the law of conservation of energy;

[0068] Step S2: using the energy value of the vibration as the boundary condition for solving the dynamic equation, and calculating the mechanism expression of the vibration displacement;

[0069] Step S3: Performing process analysis on the mechanism expression of vibration displacement to obtain rolling parameter adjustment strategies under different states;

[0070] Step S4: performing rolling mill vibration control on the rolling mill vibration system according to the rolling parameter adjustment strategy under the different states.

[0071] In this embodiment, firstly, based on the law of conservation of energy in the rolling process, the present invention reveals from the perspective of energy conversion that the fundamental cause of vibration is the excess energy in the power system. Subsequently, the calculated excess energy is used as a boundary condition to solve the mass-spring dynamic equation, thereby obtaining a vibration displacement mechanism expression with mathematical and physical meanings. Finally, the derived mechanism expression is used to analyze the cause of vibration. In view of the increase in inlet thickness fluctuation and the decrease in friction coefficient, a strategy for reducing vibration by adjusting rolling parameters such as rolling force, rolling speed and tensile stress is proposed, and the vibration control effect is good.

[0072] In step S1, the dynamic system of rolling mill vibration mainly includes roller 1, hydraulic pressing system 2, motor transmission system 3, strip steel 4 and frame 5. The energy transfer diagram of the dynamic system is shown in Figure 2 As shown. The input of the rolling mill vibration power system is the pressure of the hydraulic cylinder and the transmission of the motor transmission roller: the hydraulic pressure system 2 acts on the bearing seats on both sides of the support roller, transmits the rolling force to the working roller through the intermediate roller, and acts on the surface of the deformation zone of the strip 4, without considering the distribution of the rolling pressure along the width direction of the roller body; the motor transmission system 3 provides the torque required by the roller in the rolling process to drive the rotation of the working roller. The output of the rolling mill vibration system mainly includes the plastic deformation energy of the strip 4 when it is deformed, the friction heat generated by the contact between the working roller and the strip 4, and some other energies such as the elastic deformation energy of the roller and the instantaneous temperature rise of the strip 4 can be ignored because the values ​​are too small. When the input energy is too large and there is a surplus, vibration will occur when it exceeds a certain energy threshold.

[0073] Step S1.1: Calculate the work done by the rollers. The hydraulic pressure energy is the change in the potential energy of the working rollers in the vertical direction, and its value is equal to the work done by the rolling force P to reduce the thickness of the strip. The present invention assumes that the unit rolling pressure in the length direction of the roller body is equal, and the calculation formula for the work done by the rolling force is as follows:

[0074]

[0075] Among them, W F is the work done by the rollers, P is the rolling force in the deformation zone, and Δh is the reduction in this pass, that is, the difference between the strip entrance thickness and exit thickness.

[0076] Step S1.2: Calculate the energy of the work roll rotation. The rolling mill is generally driven by the work roll. The torque of the motor is transmitted to the work roll through the coupling, reduction box, etc., so the actual speed of the work roll is measurable. The energy of the work roll rotation is related to its own roll neck, mass, and rotation speed. The calculation process is as follows:

[0077]

[0078] Among them, the moment of inertia J of the roller is:

[0079]

[0080] Among them, W J is the energy of the working roll rotation, M is the mass of the roll, in kg; R is the radius of the roll, in mm; v r is the linear speed of the roller, in m / s; t is the rolling time. The research object in this application is the unit rolling deformation zone.

[0081] Step S1.3: Calculate the plastic deformation work of the strip. There is a certain conversion relationship between the true strain in the length direction and the true strain in the thickness direction, so the plastic deformation energy of the strip can be expressed as follows:

[0082]

[0083] Among them, W i is the plastic deformation work of the strip, V is the volume of the rolling deformation zone, the unit is mm 3 ; is the average deformation resistance of the rolling deformation zone, in MPa; h in h is the strip entrance thickness, in mm; out It is the outlet thickness of the rolled strip, in mm.

[0084] Step S1.4: Calculate the friction heat generated during the rolling process. The contact between the strip and the working roll will generate a large amount of friction heat, and the quality of friction lubrication directly determines the stability of the rolling process. Friction force will be generated at the rolling interface between the working roll and the strip, and the friction force can be decomposed into two components along the coordinate axis, namely the front slip zone and the rear slip zone. The rolling force p in the rear slip zone of the deformation zone is back and the rolling force p in the front sliding zone front The calculation formula for the frictional heat generated is obtained from the Kalman differential equation as follows:

[0085]

[0086] in:

[0087]

[0088]

[0089] Among them, W f is the friction heat generated during the rolling process, l is the length of the deformation zone, in mm; l n is the neutral plane position; Δv is the difference between the strip exit speed and the inlet speed, in m / s; p back is the rolling force in the rear sliding zone, p front is the rolling force in the front sliding zone, in N; μ is the friction coefficient; τ f is the friction force on the strip deformation zone, in N; h in h is the strip entrance thickness, in mm; out is the outlet thickness of the strip after rolling, in mm; x is the position in the deformation zone, B is the strip width, in mm; h(x) is the thickness distribution curve of the strip in the deformation zone; h′(x) is the derivative of the thickness distribution curve.

[0090] Step S1.5: Based on the work done by the rollers during rolling, the energy of the working rollers during rotation, the work of the strip steel during plastic deformation, and the frictional heat generated during the rolling process, the energy value of the vibration is calculated by the law of conservation of energy.

[0091] In this embodiment, the roll and the strip are in direct contact through the deformation zone. Studying the deformation zone of the strip can link the roll and the strip with the vibration system. Through the above calculation of various transferred energies in the vibration system, when the input energy is greater than the total output energy, there is excess energy in the system, and the vibration energy W per unit rolling deformation zone is z The calculation formula is as follows:

[0092] W z =(W F +W J )-(W i +W f) (8)

[0093] Since the setting of cold rolling schedule must meet the rolling capacity of each stand equipment, it must meet W z ≥0, which means that the input rolling force and rolling torque meet the rolling conditions; the vibration energy threshold δ is set according to the required strip thickness fluctuation range. When 0≤W z When ≤δ, the rolling process is stable.

[0094] In step S2, the energy value of the vibration is used as the boundary condition for solving the dynamic equation, and the mechanism expression of the vibration displacement is calculated.

[0095] In this embodiment, the vibration energy value obtained in step S1 is combined and used as the boundary condition for solving the dynamic equation to calculate the mechanism expression of the vibration displacement. The specific contents include:

[0096] Step S2.1: Establish a mass-spring dynamic model for the upper working roll of the rolling mill vibration system, simplify the intermediate roll as a point of concentrated mass, and ignore the damping term between the intermediate roll and the working roll;

[0097] In this embodiment, the vibration of the rolling process directly affects the thickness accuracy of the strip, and the self-excited vibration of the rolling mill must be directly generated by the contact area between the working roll and the strip, so studying the vibration of the working roll is more effective in suppressing and controlling vibration. The present invention establishes a mass-spring dynamic model for the upper working roll, simplifies the intermediate roll into a point of concentrated mass, and ignores the damping term between the intermediate roll and the working roll. This is because once vibration occurs during the rolling process, only artificial deceleration adjustment can reduce the vibration, and the vibration system cannot eliminate the vibration by itself. The mass-spring model of the working roll is as follows: Figure 3 As shown, K is the stiffness coefficient of the working roll, and M is the mass of the working roll. The displacement y of the working roll in the vertical direction is set, and the expression of the mass-spring model is established as follows:

[0098]

[0099] Among them, Δf is the fluctuation value of rolling force, the unit is N; M is the mass of the working roll, the unit is kg, and K is the stiffness between rolls, the unit is N / m.

[0100] Solving the above differential equation, we can obtain formula (10):

[0101]

[0102] Among them, C1 and C2 are two coefficients to be substituted, and y is the vibration displacement.

[0103] Step S2.2: Using the energy value of the vibration as the boundary condition for solving the mass-spring dynamics model, the mechanism expression of the vibration displacement is calculated.

[0104] In this embodiment, the mechanism expression of the vibration displacement is solved. Since the two coefficients C1 and C2 determine the amplitude of the vibration displacement, it is very necessary to reasonably determine the coefficients C1 and C2. In this embodiment, the residual energy of the power system obtained in step 1 is used as the boundary condition for solving. The energy of the working roll vibration can also be calculated by physical equations, and the calculation formula is as follows:

[0105]

[0106] in:

[0107]

[0108] The vibration energy calculated by formula (8) is the remaining energy of the vibration system. This energy can only be released in the form of working roll vibration. To maintain the stability of the dynamic system, it is equal to the energy calculated by formula (11) to combine the vibration equation with the actual production parameters. The calculation formula is as follows:

[0109]

[0110] When the start time is equal to 0, the vibration amplitude at this time is c=0. Solving the equation, we can get the values ​​of the two coefficients C1 and C2, as shown in formula (14). Finally, we put the two coefficients into formula (10) to get the vibration displacement function expression. The results show that the amplitude of the vibration displacement is related to the change of the rolling process parameters, and the vibration frequency is related to the stiffness and mass of the working roll itself. The vibration displacement equation has physical meaning.

[0111]

[0112] Where y is the vibration displacement, C1 is the first coefficient, C2 is the second coefficient, Δf is the fluctuation value of the rolling force, M is the mass of the working roll, K is the stiffness between the rolls, t is the rolling time, and h is in is the strip entrance thickness, h out is the outlet thickness of the rolled strip, V out is the strip exit speed, V in is the strip inlet speed, h m is the thickness of the strip before rolling, W z is the energy generated by vibration, which is calculated by the energy conversion formula.

[0113] In step S3, the mechanism expression of the vibration displacement is subjected to process analysis to obtain rolling parameter adjustment strategies under different states, including:

[0114] Step S3.1: Analyze the influence of the change of input parameters on the vibration displacement according to the mechanism expression of the vibration displacement, including:

[0115] In this embodiment, the vibration displacement mechanism model established by the present invention is used to analyze the cause of vibration, and the influence of the changes in parameters such as the thickness fluctuation of the strip entrance and the reduction of the friction coefficient on the vibration displacement is analyzed. The specific contents include:

[0116] Step S3.1.1: Substitute the change of the strip inlet thickness into the mechanism expression of the vibration displacement to obtain the influence of the change of the strip inlet thickness on the vibration displacement;

[0117] In this embodiment, the influence of the thickness fluctuation of the strip steel entrance on the vibration is shown in the following figure. Figure 4 As shown. Through the analysis of actual data, it can be observed that in a stable rolling process, the thickness fluctuation is kept within ±2μm. When the thickness fluctuation at the entrance of the strip increases to ±5μm, the vibration displacement amplitude increases from 0.24μm to 0.40μm, an increase of about 67%. When the thickness fluctuation at the entrance further increases to ±7μm, the vibration displacement amplitude increases to 0.56μm, an increase of about 133%.

[0118] This phenomenon is explained from the perspective of energy conversion: when the entry thickness increases, it effectively increases the reduction rate of this pass. If the rolling force is not adjusted accordingly, the energy input into the work roll by the system will increase, and at the same time, the plastic strain energy of the strip will also increase. However, at this time, the deformation resistance of the strip is reduced, and the change in deformation energy is relatively small. This leads to an overall increase in the vibration energy of the dynamic system. The external excitation caused by the thickness fluctuation further amplifies the vibration, resulting in a gradual increase in the vibration displacement of the work roll.

[0119] Step S3.1.2: Substitute the reduced value of the friction coefficient into the mechanism expression of the vibration displacement to obtain the effect of the reduced value of the friction coefficient on the vibration displacement.

[0120] In this embodiment, the influence of friction coefficient reduction on vibration displacement is analyzed by substituting friction coefficient function (15) into vibration displacement function. The curve of friction coefficient changing with rolling mileage is as follows: Figure 5 The vibration displacement function is converted to include the rolling mileage parameter. The result function shows the change of the working roll vibration displacement with the rolling mileage, as shown below Figure 6 It is obvious that the continuous decrease of friction coefficient during rolling leads to the gradual increase of working roll vibration displacement.

[0121]

[0122] Where, μ0 is the reference constant of friction coefficient related to lubrication state; μv is the reference constant of the effect of rolling speed on friction coefficient; v0 is the reference value of rolling speed, in m / s; c R is the reference constant for the effect of roller surface roughness on friction coefficient; R a is the actual roughness of the working roll surface, in μm; R a0 is the reference value of the working roll surface roughness, in μm; c w is the reference constant for the influence of the cumulative length of strip rolled by the working rolls in one roll changing cycle on the friction coefficient; L is the cumulative length of strip rolled by the working rolls in one roll changing cycle, in km; L0 is the reference value of the cumulative length of strip rolled by the working rolls in one roll changing cycle, in km.

[0123] This happens because as the surface roughness of the work roll decreases, the rolling force measured by the hydraulic system is greater than the force transmitted to the strip by the work roll. This causes excessive energy to be input into the work roll and the residual energy in the system increases. In order to maintain system stability, the work roll releases this excess energy in the form of vibration, resulting in a gradual increase in vibration displacement. When the friction coefficient is reduced from 0.024 to 0.015, the vibration displacement amplitude increases from 0.18μm to 0.71μm, an increase of about 295%, indicating that the reduction in the friction coefficient has a significant effect on vibration.

[0124] Step S3.2: According to the influence of the change of input parameters on the vibration displacement and the mechanism expression of the vibration displacement, the strategy of reducing vibration under different rolling conditions is obtained, including:

[0125] In this embodiment, the vibration control strategy is studied and analyzed based on the vibration displacement mechanism model established in this embodiment, and a strategy for reducing vibration under different rolling conditions is provided.

[0126] Step S3.2.1: According to the influence of the reduction of friction coefficient on vibration displacement and the mechanism expression of vibration displacement, the relationship between friction coefficient and vibration displacement is obtained, and the first strategy for reducing vibration is given: when the friction coefficient continues to decrease, the purpose of reducing vibration displacement is achieved by increasing the rolling speed; the second strategy for reducing vibration is: when the friction coefficient continues to decrease, the purpose of reducing vibration displacement is achieved by reducing the rolling force, increasing the tension between the stands, etc.;

[0127] In this embodiment, when the friction coefficient continues to decrease, the purpose of reducing the vibration displacement is achieved by adjusting the rolling speed.

[0128] Based on the established mechanism model, the relationship between rolling speed and friction coefficient on vibration displacement is studied. The influence of friction coefficient and working roll rolling speed on vibration displacement is as follows Figure 7As shown in Figure 2, during uniform rolling, when the linear speed of the work roll is 22 m / s, as the friction coefficient decreases from 0.025 to 0.015, the vibration displacement amplitude increases from 0.433 μm to 0.882 μm. In this case, reducing the rolling speed will continue to increase the vibration amplitude, but increasing the rolling linear speed will reduce the vibration displacement until it stabilizes within an acceptable range.

[0129] When the friction coefficient is reduced to 0.018 and the rolling speed is increased from 19.0m / s to 23.0m / s, the vibration displacement amplitude decreases from 1.057μm to 0.637μm, a decrease of 39.7%. Similarly, when the friction coefficient is 0.025, when the rolling speed increases from 19.0m / s to 23.0m / s, the vibration displacement amplitude decreases from 0.921μm to 0.208μm, a decrease of 77.4%. It can be clearly seen from this analysis that when the friction coefficient is high during rolling, the vibration displacement is significantly smaller. When the friction coefficient is reduced, appropriately increasing the rolling speed can effectively control the mill vibration.

[0130] As the rolling mileage increases, the friction coefficient decreases and the vibration displacement increases. In order to find a reasonable vibration reduction solution, Figure 8 The change in the vibration displacement amplitude of the working roll at a rolling mileage of 50 kilometers and a friction coefficient of 0.018 by adjusting the front and rear tensile stresses is illustrated. When the back tensile stress increases from 240MPa to 330MPa and the front tensile stress increases from 210MPa to 300MPa, the vibration displacement amplitude of the working roll decreases from 0.71μm to 0.65μm, an overall decrease of 8.5%. This is because when the friction coefficient decreases, the energy output of the system decreases, resulting in an increase in excess energy. At this point, increasing the front and rear tensile stresses reduces the rolling force required to achieve the same exit thickness and reduces the energy input of the system, thereby maintaining a balance between input and output energy. However, simply adjusting the front and rear tensile stresses is not enough to maintain the stability of the system.

[0131] Step S3.2.2: According to the influence of the change of strip entrance thickness on the vibration displacement and the mechanism expression of vibration displacement, the relationship between the strip entrance thickness and the rolling force and the tension between the frames is obtained, and the first strategy to reduce vibration is given: when the strip entrance thickness changes, the rolling force value is reduced by reducing the amount of reduction, and the tension between the frames is increased simultaneously to achieve stability of the rolling process.

[0132] When the abnormal fluctuation of the entrance thickness increases, the rolling force value is adjusted by adjusting the pressure reduction, and the tension between the stands is adjusted in a coordinated manner to ensure the stability of the rolling process while reducing the vibration displacement.

[0133] Under the rolling condition where the friction coefficient is continuously decreasing, in addition to adjusting the rolling speed, the rolling force can also be adjusted to reduce the vibration displacement amplitude. The results of the vibration displacement changing with the rolling force and the friction coefficient are shown in Fig. 9 As shown. When the friction coefficient is reduced from 0.025 to 0.016, the vibration displacement increases continuously. In the process of reducing the friction coefficient, the rolling force is adjusted from 7850kN to 7700kN, so that the vibration displacement amplitude of the working roll is reduced from 0.46μm to 0.78μm to 0.23μm to 0.62μm. When the friction coefficient is high, the vibration displacement amplitude is reduced by 50%, and when the friction coefficient is low, it is only reduced by 20.5%. The results show that when the friction coefficient is too low, it is not enough to adjust the rolling force alone, and other parameters must also be adjusted. In addition, when the friction coefficient is low, if the rolling force is too small, slippage between the strip and the roll is likely to occur, which is also not conducive to rolling stability.

[0134] When the strip entrance thickness increases, the effect of adjusting the rolling force on the vibration displacement is as follows: Fig.10 As shown. When the entry thickness fluctuation increases from ±3μm to ±7μm, that is, when the strip entry thickness increases from 0.403mm to 0.407mm, the work roll performs too much work. By reducing the rolling force to reduce energy input, the rolling force is reduced from 7850kN to 7700kN, resulting in a decrease in the vibration displacement amplitude from 0.598μm to 0.451μm, a decrease of 24.7% compared to the value before adjustment.

[0135] The various embodiments in the present application are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0136] The protection scope of the present application is not limited to the above-mentioned embodiments. Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the scope and spirit of the present disclosure. If these changes and modifications fall within the scope of the claims of the present disclosure and their equivalents, the intention of the present disclosure also includes these changes and modifications.

Claims

1. A rolling mill vibration control method based on a mechanism analysis model, characterized in that: include: Determine the energy transmission path of the rolling mill vibration system, calculate the energy value of each energy transmission path, and calculate the energy value of the vibration according to the energy value of each energy transmission path by the law of conservation of energy; The energy value of the vibration is used as the boundary condition for solving the dynamic equation to calculate the mechanism expression of the vibration displacement; The mechanism expression of vibration displacement is analyzed to obtain the rolling parameter adjustment strategy under different conditions. The rolling mill vibration system is subjected to rolling mill vibration control using the rolling parameter adjustment strategy under the different states.

2. A rolling mill vibration control method based on a mechanism analysis model according to claim 1, characterized in that: The calculating the energy value of each energy transmission path includes: Calculate the work done by the rollers in pressing down; Calculate the energy of work roll rotation; Calculate the plastic deformation work of the strip; Calculate the frictional heat generated during the rolling process.

3. A rolling mill vibration control method based on a mechanism analysis model according to claim 1, characterized in that: The step of calculating the energy value of the vibration according to the energy value of each energy transmission path by using the law of conservation of energy includes: The energy value of the vibration is calculated by the law of conservation of energy based on the work done by the rollers, the energy of the working rollers rotating, the work of plastic deformation of the strip, and the friction heat generated during the rolling process.

4. A rolling mill vibration control method based on a mechanism analysis model according to claim 1, characterized in that: The energy value of the vibration is calculated as follows: IN z =(In F +W J )-(IN i +W f ) Among them, W z is the energy value of the vibration, W F is the work done by the roller pressing down, W J is the energy of the working roll rotation, W i is the plastic deformation work of the strip, W f It is the friction heat generated during the rolling process.

5. A rolling mill vibration control method based on a mechanism analysis model according to claim 1, characterized in that: The energy value of the vibration is used as the boundary condition for solving the dynamic equation to calculate the mechanism expression of the vibration displacement, including: A mass-spring dynamic model is established for the upper working roll of the rolling mill vibration system, the intermediate roll is simplified as a point of concentrated mass, and the damping term between the intermediate roll and the working roll is ignored. The energy value of the vibration is used as the boundary condition for solving the mass-spring dynamics model, and the mechanism expression of the vibration displacement is calculated.

6. A rolling mill vibration control method based on a mechanism analysis model according to claim 5, characterized in that: The mass-spring dynamics model is calculated as follows: Among them, Δf is the fluctuation value of rolling force, M is the mass of working roll, K is the stiffness between rolls, and y is the vibration displacement.

7. A rolling mill vibration control method based on a mechanism analysis model according to claim 5, characterized in that: The energy value of the vibration is used as the boundary condition for solving the mass-spring dynamics model to calculate the mechanism expression of the vibration displacement. The calculation process is as follows: The mass-spring dynamics model is solved to obtain the solution, and the calculation formula is as follows: Among them, Δf is the fluctuation value of rolling force, M is the mass of working roll, K is the stiffness between rolls, y is the vibration displacement, C1 is the first coefficient, and C2 is the second coefficient; The energy of the working roll vibration is calculated as follows: Among them, W 振动 is the energy of the working roll vibration, W 势能 is the potential energy of the working roll, W 动能 For the kinetic energy of work; in, Where, v is the speed of the roller; The energy value of the vibration is used as the boundary condition for solving the mass-spring dynamics model to obtain the equation, which is calculated as follows: When the time of starting the rolling roll is equal to 0, the vibration amplitude at this time is c=0, and the value of the first coefficient C1 and the value of the second coefficient C2 are obtained by solving the equation. The value of the first coefficient C1 and the value of the second coefficient C2 are substituted into the calculation formula of the solution result to obtain the mechanism expression of the vibration displacement: Where y is the vibration displacement, C1 is the first coefficient, C2 is the second coefficient, Δf is the fluctuation value of the rolling force, M is the mass of the working roll, K is the stiffness between the rolls, t is the rolling time, and h is in is the strip entrance thickness, h out is the outlet thickness of the rolled strip, V out is the strip exit speed, V in is the strip inlet speed, h m is the thickness of the strip before rolling, W z The energy that generates vibration.

8. A rolling mill vibration control method based on a mechanism analysis model according to claim 1, characterized in that: The process analysis of the mechanism expression of vibration displacement is performed to obtain the rolling parameter adjustment strategies under different states, including: According to the mechanism expression of the vibration displacement, the influence of the change of input parameters on the vibration displacement is analyzed; According to the influence of input parameter changes on vibration displacement and the mechanism expression of vibration displacement, the strategy to reduce vibration under different rolling conditions is obtained.

9. A rolling mill vibration control method based on a mechanism analysis model according to claim 8, characterized in that: The step of analyzing the influence of the change of input parameters on the vibration displacement according to the mechanism expression of the vibration displacement includes: Substituting the change of the strip steel inlet thickness into the mechanism expression of the vibration displacement, the influence of the change of the strip steel inlet thickness on the vibration displacement is obtained; Substituting the reduced value of the friction coefficient into the mechanism expression of the vibration displacement, the influence of the reduced value of the friction coefficient on the vibration displacement is obtained.

10. A rolling mill vibration control method based on a mechanism analysis model according to claim 8, characterized in that: According to the influence of the change of input parameters on the vibration displacement and the mechanism expression of the vibration displacement, the strategy of reducing vibration under different rolling conditions is obtained, including: According to the influence of friction coefficient reduction on vibration displacement and the mechanism expression of vibration displacement, the relationship between friction coefficient and vibration displacement is obtained, and the first strategy to reduce vibration is given: when the friction coefficient continues to decrease, the purpose of reducing vibration displacement is achieved by increasing the rolling speed; the second strategy to reduce vibration is: when the friction coefficient continues to decrease, the purpose of reducing vibration displacement is achieved by reducing the rolling force or increasing the tension between the stands; According to the influence of the change of strip entrance thickness on the vibration displacement and the mechanism expression of vibration displacement, the relationship between the strip entrance thickness and the rolling force and the tension between the frames is obtained. The first strategy to reduce vibration is given: when the strip entrance thickness changes, the rolling force value is reduced by reducing the amount of pressure reduction, and the tension between the frames is increased simultaneously to achieve the purpose of reducing vibration displacement.

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