A method for controlling a roll lubricating device of a hot continuous rolling finishing mill train

Abstract

The application discloses a kind of hot continuous rolling finishing mill set roll lubricating device control method, comprising the following steps: S1, whether the strip steel reaches finishing mill is detected;S2, the rolling force and rolling mill speed when the finishing mill is locked in biting steel;S3, the roll rolling force feedback control model and rolling speed feedback control model of the finishing mill are established;S4, the strip steel temperature characteristic compensation coefficient is established;S5, the injection timing of roll lubricating device is set.The present application is to solve the problem of poor lubrication effect of finishing stand roll, and to improve the edge quality of hot-rolled strip steel (especially high-grade silicon steel).

Description

Technical Field

[0001] This invention relates to hot rolling electrical technology, and more specifically, to a control method for a roll lubrication device in a hot continuous rolling mill finishing unit. Background Technology

[0002] Hot rolling lubrication technology has a long history of application in hot strip mills. It not only reduces energy consumption, increases productivity, lowers roll costs, and improves strip surface quality, but also improves the grain structure of the strip, resulting in ideal deep-drawing performance. With the expansion of product varieties, higher customer requirements, the development of short-process continuous casting and rolling processes, and the increasing market demand for hot-rolled strip steel with a thickness of less than 1 mm, hot rolling lubrication technology has attracted widespread attention and is now widely used. Currently, with the use of high-speed steel rolls, hot rolling lubrication technology is even more important. It involves mixing lubricating oil and cooling water in a specific ratio and then spraying the mixture onto the rolls under pressure. This forms a lubricating film on the contact surface between the work rolls and the workpiece, providing lubrication, reducing rolling force on the stand, and mitigating roll wear. Practice has proven that, under the same conditions, hot rolling lubrication is the most effective means of reducing rolling force. The width accuracy of hot-rolled strip is a crucial indicator of the quality of hot-rolled finished products. Precise width control means a stable and smaller width tolerance range, which not only improves product yield but also creates better production conditions for hot-rolling users and subsequent processes. The vertical rolls of the finishing mill are essential equipment for controlling the strip width in the finishing rolling area. In recent years, with downstream customers demanding increasingly higher product quality from hot-rolled production lines, improving strip edge quality and reducing edge defects caused by poor vertical roll surface conditions has become increasingly urgent. Currently, installing a finishing mill vertical roll lubrication device on the production line can improve strip edge quality, increase yield, and extend the vertical roll changeover cycle.

[0003] However, the following problems exist during use:

[0004] 1. In actual application, if the side pressure of the finishing vertical roll mill increases, the friction between the strip edge and the roll will increase. If the lubrication control is based on a fixed oil-water mixing ratio, the expected lubrication effect will not be achieved, the mill stand rolling force will be too large, and the roll wear will be aggravated.

[0005] 2. If the side pressure of the finishing vertical roll mill is reduced, the friction between the strip edge and the roll will decrease. If a fixed oil-water mixing ratio is used for lubrication control, the fixed oil-water mixing ratio will produce an excessive lubrication effect, which will easily cause the stand to slip.

[0006] 3. If the rolling speed of the finishing vertical roll mill increases, using a fixed oil-water mixing ratio will not achieve the expected lubrication effect, and the wear of the rolls will be aggravated.

[0007] 4. If the rolling speed of the finishing vertical roll mill decreases, using a fixed oil-water mixing ratio will result in excessive lubrication. Even when the rolled piece leaves the stand, there will still be lubricating oil adhering to the surface of the roll, which may cause slippage when the next strip is bitten. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a control method for the roll lubrication device of a hot strip mill finishing unit, in order to solve the problem of poor lubrication effect of the finishing vertical rolls, which often results in under-lubrication and over-lubrication, and to improve the edge quality of hot-rolled strip steel products (especially high-grade silicon steel).

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A method for controlling the roll lubrication device of a hot continuous rolling mill finishing unit includes the following steps:

[0011] S1, Check if the strip steel has arrived at the finishing mill;

[0012] S2, lock the rolling force and mill speed of the finishing mill when it bites the steel;

[0013] S3, apply the rolling force feedback control model and rolling speed feedback control model of the finishing mill to control the rolling force and rolling speed;

[0014] S4, apply the strip temperature characteristic compensation coefficient for temperature compensation;

[0015] S5, set the spraying sequence of the roll lubrication device.

[0016] Preferably, in step S3, the calculation formula for the roll rolling force feedback control model is:

[0017]

[0018] In the formula, R1 n R1 represents the current output coefficient of the roll rolling force feedback control model; n-1 The output coefficients of the roll rolling force feedback control model at the previous moment; RF n F is the actual rolling force at the current moment; F is the actual rolling force locked at the moment the roll bites the steel; RF n-1 This represents the actual rolling force of the rolls at the previous moment.

[0019] Preferably, in step S3, the calculation formula for the rolling speed feedback control model is:

[0020]

[0021] In the formula, R2 nR2 represents the current output coefficient of the rolling speed feedback control model. n-1 RS represents the output coefficient of the rolling speed feedback control model at the previous moment. n S represents the actual rolling force at the current moment; S represents the actual rolling force locked at the moment the roll bites the steel; RS n-1 This represents the actual rolling force of the rolls at the previous moment.

[0022] Preferably, in step S4, the strip temperature characteristic compensation coefficient is as follows:

[0023] K10 = A10i * R10 + B10i

[0024] K11=A11 i*R11+B11 i

[0025] K12=A12i*R12+B12i

[0026] K13 = A13i * R13 + B13i

[0027] …

[0028] K19 = A19i * R19 + B19i

[0029] In the above formula, K1x is the strip edge temperature drop time characteristic layering compensation coefficient; A10~A19 are the strip edge temperature drop time characteristic compensation layering proportional gain coefficients (0~9); R10~R19 are the strip edge temperature ten-segment layering interval values; B10~B19 are the strip edge temperature drop time characteristic compensation layering adjustment coefficients (0~9); i is the temperature difference input; K is the output value corresponding to the temperature difference input.

[0030] Preferably, in step S5, the control of the spraying timing of the roll lubrication device is as follows:

[0031] The injection timing T-open of the roll lubrication device is set to be activated after the roll biting signal is established plus a delay, i.e.:

[0032] T-open: F1 LOAD ON + TD

[0033] When the distance S0 between the tail of the rolled piece and the roll is less than S1+α, the roll lubrication spray device is turned off, i.e.:

[0034] T-close:S0 <S1+α

[0035] Where S1 is the distance of one rotation of the roll, S1=π×R, R is the diameter of the roll; α is the compensation value.

[0036] The present invention provides a control method for the roll lubrication device of a hot strip mill finishing unit. This method primarily changes the current roll lubrication control method in edge finishing mills by establishing a rolling force feedback control model, a speed feedback control model, and related timing control. It offers the following advantages:

[0037] 1. By improving the lubrication setpoint control method using existing equipment, the lubrication effect of the hot rolling mill rolls was improved, thereby improving the surface quality of hot-rolled products;

[0038] 2. When the rolling load of the finishing mill rolls is less than the traditional empirical value, the amount of lubricant used is reduced while achieving the lubrication effect;

[0039] 3. When the rolling load of the finishing mill rolls exceeds the traditional empirical value, it can ensure that the finishing mill rolls receive sufficient and effective lubrication;

[0040] 4. It has good versatility and adaptability, and high reliability. It is suitable for other hot rolling mill roll lubrication systems controlled by PLC logic programs. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the layout of existing finishing mill rolls and related equipment;

[0042] Figure 2 This is a schematic diagram of the structural framework of the roll lubrication control system of an existing finishing mill;

[0043] Figure 3 This is a logic diagram of the control method for the roll lubrication device of the present invention;

[0044] Figure 4 This is a logical schematic diagram of the roll rolling force feedback control model in the roll lubrication device control method of the present invention;

[0045] Figure 5 This is a logical schematic diagram of the rolling speed feedback control model in the control method of the roll lubrication device of the present invention;

[0046] Figure 6 In the embodiment of the control method for the roll lubrication device of the present invention, after the vertical roll lubrication control is started, the corresponding rolling speed, rolling force feedback and control output pump speed change lubrication data tracking curve screenshot are shown. Detailed Implementation

[0047] To better understand the above-mentioned technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0048] Combination Figure 1As shown, a hot metal detector is installed on the roll inlet side of the finishing mill (in the direction of the incoming steel billet material) to detect the position of the incoming material head. A finishing mill descaling box and descaling roller table are installed in front of the hot metal detector. The finishing mill F1 is located on the roll outlet side of the finishing mill.

[0049] Combination Figure 2 As shown, the finishing mill roll lubrication control system consists of a finishing mill F1 control PLC, a finishing mill roll lubrication control device, and a lubrication pump motor speed control device. The finishing mill F1 control PLC is responsible for collecting the fixed lubricating oil-to-water ratio sent by L2, collecting feedback from the F1 stand rolling force and mill speed, and calculating the lubrication start and end times. The finishing mill roll lubrication control device receives relevant signals and values ​​from the finishing mill F1 control PLC and controls the lubrication pump motor speed control device to adjust the pump speed, thereby changing the oil-to-water ratio at the lubrication pipeline outlet to achieve better lubrication.

[0050] Combination Figure 3 As shown, the present invention provides a method for controlling the roll lubrication device of a hot strip mill finishing unit, comprising the following steps:

[0051] S1, Check if the strip steel has arrived at the finishing mill;

[0052] S2, locks the rolling force and mill speed of the finishing mill when it bites the steel;

[0053] S3, Establish the rolling force feedback control model and rolling speed feedback control model of the finishing mill;

[0054] S4, Establish the temperature characteristic compensation coefficient of strip steel;

[0055] S5, set the spraying sequence of the roll lubrication device.

[0056] The calculation formula for the roll rolling force feedback control model is as follows:

[0057]

[0058] In the formula, R1 n R1 represents the output coefficients of the roll rolling force feedback control model at the current time (time n); n-1 The output coefficients of the roll rolling force feedback control model at the previous time step (time step n-1); RF n F represents the actual rolling force at the current moment (time n); F represents the actual rolling force locked at the moment the roll bites the steel. RF n-1 This represents the actual rolling force at the previous moment (moment n-1).

[0059] Combination Figure 4As shown, the roll rolling force feedback control model extracts the rolling force of stand F1 at the current moment and the rolling force locked when stand F1 bites the steel, performs logical operations, and then inputs it into the R controller as the proportional coefficient. Simultaneously, it compares the current rolling force of F1 roll with the rolling force of F1 roll at the previous moment, and uses this comparison as the input value of the R controller. This input value enters the I controller for integration processing, is added to the original R controller output value, and then enters the L controller. Finally, after amplitude limiting processing, the current moment (n) output coefficient R1n of the roll lubrication rolling force feedback control model is obtained.

[0060] The calculation formula for the rolling speed feedback control model is:

[0061]

[0062] In the formula, R2 n R² represents the output coefficients of the rolling speed feedback control model at the current time (time n); n-1 The output coefficients of the rolling speed feedback control model at the previous time step (time step n-1); RS n S represents the actual rolling force at the current moment (time n); S represents the actual rolling force locked at the moment the roll bites the steel; RS n-1 This represents the actual rolling force at the previous moment (moment n-1).

[0063] Combination Figure 5 As shown, the rolling speed feedback control model extracts the current rolling force of stand F1 and divides it by the rolling speed locked when stand F1 bites the steel. This division is then fed into the R controller as the proportional coefficient. Simultaneously, the current rolling speed of stand F1 is compared with the previous rolling speed of stand F1, and this comparison is used as the input value to the R controller. This input value is then integrated by the I controller and added to the original R controller output value before being fed into the L controller. Finally, after amplitude limiting, the current time (n) output coefficient R2n of the roll lubrication rolling speed feedback control model is obtained.

[0064] The establishment of the strip temperature characteristic compensation coefficient is as follows:

[0065] K10 = A10i * R10 + B10i

[0066] K11=A11i*R11+B11i

[0067] K12=A12i*R12+B12i

[0068] K13 = A13i * R13 + B13i

[0069] …

[0070] K19 = A19i * R19 + B19i

[0071] In the above formula, K1x (x = 0-9) is the stratification compensation coefficient for the temperature drop time characteristic of the strip edge; A10~A19 is the proportional gain coefficient for the stratification compensation of the temperature drop time characteristic of the strip edge (0~9); R10~R19 is the stratification interval value of the temperature drop time characteristic of the strip edge (10 segments); B10~B19 is the adjustment coefficient for the stratification compensation of the temperature drop time characteristic of the strip edge (0~9).

[0072] Because the temperature of the strip decreases along its length, especially at the tail end where the temperature drop can reach 50 degrees Celsius or more, it is generally believed that the higher the temperature, the faster the lubricating oil burns, and the lower the temperature, the slower the lubricating oil burns. Therefore, a strip temperature characteristic compensation coefficient is established to optimize the lubricating oil injection quantity.

[0073] The specific control of the spray timing of the roll lubrication device is as follows:

[0074] To ensure rolling stability and prevent slippage of the workpiece head during rolling, the spray timing T-open of the roll lubrication device is set to activate after a delay following the establishment of the roll bite signal.

[0075] T-open: F1 LOAD ON + TD

[0076] To ensure that no lubricating oil residue remains on the roll surface after the strip is rolled, thus preventing slippage during the rolling of the next strip, the tail of the strip needs to be tracked. The distance S1 of one roll rotation needs to be calculated. When the distance S0 between the tail of the strip and the roll is less than S1 + α (compensation value), the roll lubrication spray device is turned off to ensure that the lubricating oil on the roll surface is completely burned off, preventing slippage when the next strip enters the mill. That is:

[0077] T-close:S0 <S1+α

[0078] Where S1 is the distance of one rotation of the roll, S1=π×R, R is the diameter of the roll; α is the compensation value.

[0079] Example

[0080] This embodiment provides a method for controlling the roll lubrication device of a hot continuous rolling mill, which includes the following steps:

[0081] S1, Check if the strip steel has arrived at the finishing mill;

[0082] S2, locks the rolling force and mill speed of the finishing mill when it bites the steel;

[0083] S3, Establish the rolling force feedback control model and rolling speed feedback control model of the finishing mill;

[0084] S4, Establish the temperature characteristic compensation coefficient of strip steel;

[0085] S5, set the spraying sequence of the roll lubrication device.

[0086] like Figure 6 As shown, in this embodiment, during the control process, at time point X1, the rolling force feedback control compensation coefficient is 1.1723; the speed feedback compensation coefficient is -0.0386; the strip temperature characteristic compensation coefficient is 9; and the total compensation coefficient is 2.0337.

[0087] At time point X2, the rolling force feedback control compensation coefficient is 2.00; the speed feedback compensation coefficient is 0.2779; the strip temperature characteristic compensation coefficient is 3.71; and the total compensation coefficient is 2.6489.

[0088] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any variations or modifications to the above embodiments that are within the essential spirit of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A control method for the roll lubrication device of a hot continuous rolling mill finishing unit, characterized in that, Includes the following steps: S1, Check if the strip steel has arrived at the finishing mill; S2, lock the rolling force and mill speed of the finishing mill when it bites the steel; S3, the rolling force and rolling speed are controlled using the rolling force feedback control model and rolling speed feedback control model of the finishing mill. The calculation formula for the rolling force feedback control model of the roll is: ； In the formula, The output coefficients of the roll rolling force feedback control model at the current moment; The output coefficient of the roll rolling force feedback control model at the previous moment; This represents the actual rolling force of the roll at the current moment. To lock the actual rolling force value at the moment the rolls bite the steel; This represents the actual rolling force of the rolls at the previous moment. The calculation formula for the rolling speed feedback control model is as follows: ； In the formula, The output coefficients of the rolling speed feedback control model at the current moment; The output coefficients of the rolling speed feedback control model at the previous moment; This represents the actual rolling force of the roll at the current moment. To lock the actual rolling force value at the moment the rolls bite the steel; This represents the actual rolling force of the rolls at the previous moment. S4, apply the strip temperature characteristic compensation coefficient for temperature compensation; S5, set the spraying sequence of the roll lubrication device.

2. The control method for the roll lubrication device of a hot continuous rolling mill according to claim 1, characterized in that, In step S4, the strip temperature characteristic compensation coefficient is specifically as follows: K10 = A10i * R10 + B10i K11=A11i*R11+B11i K12=A12i*R12+B12i K13 = A13i * R13 + B13i … K19 = A19i * R19 + B19i In the above formula, K1x is the strip edge temperature drop time characteristic layering compensation coefficient; A10~A19 are the strip edge temperature drop time characteristic compensation layering proportional gain coefficients (0~9); R10~R19 are the strip edge temperature ten-segment layering interval values; B10~B19 are the strip edge temperature drop time characteristic compensation layering adjustment coefficients (0~9); i is the temperature difference input; K is the output value corresponding to the temperature difference input.

3. The control method for the roll lubrication device of a hot continuous rolling mill according to claim 1, characterized in that, In step S5, the control of the spraying timing of the roll lubrication device is as follows: The injection timing T-open of the roll lubrication device is set to be activated after the roll biting signal is established plus a delay, i.e.: T-open: F1 LOAD ON + TD When the distance S0 between the tail of the rolled piece and the roll is less than S1+α, the roll lubrication spray device is turned off, i.e.: T-close:S0 <S1+α Where S1 is the distance of one rotation of the roll, S1=π×R, R is the diameter of the roll; α is the compensation value.

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