Rolling force deviation detection control method for reversible hot rolling mill

Abstract

The invention discloses a rolling force deviation detection control method for a reversible hot rolling mill. The method comprises the following steps that S1, the state of a rolling force detection device is analyzed; s2, the rolling length distance of the rack is judged; s3, judging the load of the rack; s4, judging signals of a rear width gauge of the rolling mill; and S5, comprehensively judging a steel throwing signal of the rolling mill. The problems of control failure and abnormal shutdown caused by the fact that the rolling mill cannot detect steel biting and steel throwing signals due to abnormal rolling force detection of the rough rolling mill can be avoided, and safe use of the hot rolling mill is guaranteed.

Description

Technical Field

[0001] The present invention relates to a metallurgical steel rolling automatic control technology, and more particularly to a rolling force deviation detection and control method for a hot rolling reversible rolling mill. Background Art

[0002] The rolling force detection of a reversible mill (roughing mill) is the core detection equipment for roughing automation control. It uses a pressure gauge installed on the roughing mill to measure the rolling force applied to the mill during the rolling process. Hot roughing is a reversible mill. During normal rolling, the strip position is calculated using the load signal from the roughing mill pressure gauge. Furthermore, after the steel is cast, the position tracking of the reversible mill is controlled by the load loss signal. In actual on-site production, due to the long-term erosion of descaling moisture and dust, if the side pressure gauge of the reversible mill detects an anomaly, it will cause an abnormality in the frame load signal, leading to a malfunction and the mill being unable to receive the steel biting and casting signals. This can cause the mill's automation control to fail, resulting in problems such as steel jamming, strip tracking anomalies, and abnormal speeds of the front and rear rollers.

[0003] Existing patent applications, such as Chinese patent application No. 201410010253.7, disclose a method for detecting the rolling force of a stand of a computer-controlled rolling mill in hot rolling, comprising the following steps: obtaining the rolling force under hydraulic pressure; inputting the rolling force detected by the pressure measuring head; detecting static deviation under different pressure measuring methods; detecting dynamic deviation under different measuring methods; detecting the deviation of rolling force at different PC angles; and compensating for the deviation of the hydraulic rolling force. Because the method of the present invention uses actual on-site production process parameters as input values ​​in the finite element model, it is close to the actual production environment and can truly reflect the changes in deformation resistance in each stand of the continuous rolling mill. The method can optimize the deformation resistance model of the secondary system; use the corrected deformation resistance value to optimize the rolling force setting value, improve the preset accuracy of the rolling force, ensure the stability of the rolling process, and improve product quality. The present invention realizes an online rolling force detection and control technology through dynamic deviation compensation control and integrated dynamic and static deviation control.

[0004] For example, Chinese patent application No. 201720676468.1 discloses a rolling force monitoring device for a finishing mill, which relates to the field of finishing mill equipment. The device includes: an arc pad, a step pad, an upper pressure plate, a roll-changing pulley, a lower pressure plate, two roll-changing pulley slides, a pressure head upper cover, an upper equalizing pressure plate, a pressure head, a lower equalizing pressure plate, a pressure head base, and a rolling mill arch base. The positional relationship of the above components is connected in sequence from top to bottom. The above device solves the technical problem in the prior art that the actual pressure difference monitoring of the pressure heads on both sides of the rolling mill fluctuates greatly due to the uneven force on the lower equalizing pressure plate of the pressure head.

[0005] For example, Chinese patent application No. 200710005912.8 discloses a method for determining the rolling force in a rolling mill stand and a rolling mill stand, wherein the rolling mill stand has at least one roll, whose roll neck (or its roll shaft) is rotatably supported in a so-called eccentric sleeve; wherein each eccentric sleeve is rotatably supported in the housing of the rolling mill stand; these supports of the eccentric sleeve are low-friction bearings; an adjustment mechanism is provided, by means of which an adjustment force can be applied to the eccentric sleeve so that the eccentric sleeve rotates relative to the housing in which the eccentric sleeve is supported and is maintained in a desired position; the method comprises the following steps: when the eccentric sleeve is maintained in the desired position, measuring the adjustment force; and determining the rolling force from the measured adjustment force.

[0006] For example, Chinese patent application No. 200910251586.8 discloses a method for correcting the deformation resistance generated during the seven-stand continuous rolling process of non-oriented electrical steel on a CSP production line. The method comprises the following steps: 1) collecting actual measured rolling force data; 2) applying the actual measured rolling force data to the Sims unit rolling force formula to derive an initial value for the deformation resistance; and 3) correcting the initial value for the deformation resistance. Because the method of the present invention uses actual on-site production process parameters as input values ​​in the finite element model, it closely resembles the actual production environment and can accurately reflect the changes in deformation resistance in each stand of the continuous rolling mill. The method can also optimize the deformation resistance model of the secondary system. The corrected deformation resistance value is used to optimize the rolling force setting value, thereby improving the preset accuracy of the rolling force, ensuring a stable rolling process, and improving product quality.

[0007] The aforementioned four existing patents differ fundamentally from the present invention. The present invention calculates the strip position during normal rolling of a reversing mill, typically using the load signal from the roughing mill's pressure gauge to achieve position control. Therefore, this technical solution implements a series of technical measures to achieve comprehensive control of the rolling force detection device's state prejudgment, thereby determining whether the current rolling force detection is in a normal state. Simultaneously, auxiliary facilities supporting the reversing mill are utilized to verify the normal operation of the rolling force detection device and assist in tracking the strip position. Summary of the Invention

[0008] In view of the defects existing in the prior art, the purpose of the present invention is to provide a rolling force deviation detection and control method for a hot rolling reversible rolling mill, which can avoid the problems of control failure and abnormal shutdown of the rolling mill due to abnormal rolling force detection of the roughing mill, such as the inability to detect steel biting and steel throwing signals, and ensure the safe use of the hot rolling mill.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] A method for detecting and controlling rolling force deviation of a hot rolling reversible rolling mill comprises the following steps:

[0011] S1, analyzing the state of the rolling force detection device;

[0012] S2, judging the rolling length of the stand;

[0013] S3, determine the rack load;

[0014] S4, judging the signal of the width gauge after the rolling mill;

[0015] S5, comprehensively judge the steel throwing signal of the rolling mill.

[0016] Preferably, the step S1 specifically includes:

[0017] Calculate the average rolling force when the rolling mill is unloaded:

[0018]

[0019] Where, is the average rolling force when no load is applied, P i is the instantaneous rolling force;

[0020] Calculate the rolling force variance:

[0021]

[0022]

[0023] Where S 2 is the rolling force variance, σ is the fluctuation allowable amplitude, and K is the variance coefficient; when When the no-load rolling force fluctuates too much, the rolling force detection is abnormal or the rolling mill transmission system is blocked, an abnormal rolling force alarm is issued;

[0024] The value of λ is based on the maximum rolling force when the rolling mill is unloaded;

[0025] When S 2 When ≥σ, the no-load rolling force fluctuates too much, the rolling force detection is unstable and abnormal, and an abnormal rolling force alarm is issued.

[0026] Preferably, the step S2 specifically includes:

[0027]

[0028] L = πD × n × t

[0029] Where, L 后 is the length after rolling, L 前 is the original length of the strip, H 后 is the thickness after rolling, H 前 is the original thickness of the strip, L 轧 is the rolling length of the roller, D is the roller diameter, n is the roller speed, and t is the rolling time; when L轧 >L 后 When , strip rolling is completed.

[0030] Preferably, the step S3 specifically includes:

[0031] when When the mill bites steel, the mill enters the continuous rolling state;

[0032] Where, α is the setting value of the steel rolling steel bite signal;

[0033] Calculate the average rolling force in the load state after biting the steel:

[0034]

[0035] Where, is the average rolling force when no load is applied, P i is the instantaneous rolling force;

[0036] then, The rolling mill is finished rolling steel.

[0037] Preferably, the step S4 specifically includes:

[0038] The width gauge at the rough rolling exit is used to detect the completion signal and make a secondary position judgment on the actual strip to determine whether the strip is abnormal.

[0039] Preferably, the step S5 specifically includes:

[0040] When the rolling force detection mill is finished rolling the steel, if the rolling length is greater than the strip rolled length, the normal steel rolling is completed; if the rolling length is less than the strip rolled length, it means that the rolling force jumps abnormally, an alarm is issued, and the width gauge is used to detect the falling edge of the completion signal instead of the steel throwing signal;

[0041] When the rolling mill is in the continuous rolling state and the width gauge detection signal at the rough rolling exit is triggered, the rolling length has also been reached, but the frame load judgment is still in the continuous rolling state, indicating that there is a problem with the rolling force detection. At this time, an alarm is issued and the roller is locked to avoid rushing into the finishing rolling area and causing tracking errors.

[0042] The present invention provides a method for detecting and controlling rolling force deviations in a hot rolling reversible mill, capable of pre-analyzing whether the rolling force detection device is in a normal state. Auxiliary facilities associated with the reversible mill are used to verify the normal operation of the rolling force detection device and assist in tracking the position of the strip. During rough rolling, a large amount of water mist, dust, and oil contamination can affect the normal operation of the detection instrument. Auxiliary equipment is used to provide multi-faceted protection against abnormal rolling force deviations during the rolling process. Pre-analyzing the status of the rolling force detection device before rolling can reduce the risk of failure during the rolling process. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a flow chart of the rolling force deviation detection and control method of the hot rolling reversible rolling mill of the present invention. DETAILED DESCRIPTION

[0044] In order to better understand the above technical solutions of the present invention, the technical solutions of the present invention are further described below with reference to the accompanying drawings and embodiments.

[0045] Combine Figure 1 As shown, the present invention provides a method for detecting and controlling rolling force deviation of a hot rolling reversible rolling mill, comprising the following steps:

[0046] S1, analyzing the state of the rolling force detection device;

[0047] S2, judging the rolling length of the stand;

[0048] S3, determine the rack load;

[0049] S4, judging the signal of the width gauge after the rolling mill;

[0050] S5, comprehensively judge the steel throwing signal of the rolling mill.

[0051] The above step S1 specifically includes:

[0052] When the rolling mill is unloaded, its rolling force generally fluctuates within a small range. When it exceeds a certain range or is generally too large, it can be considered abnormal.

[0053] Calculate the average rolling force when the rolling mill is unloaded:

[0054]

[0055] Where, is the average rolling force when no load is applied, P i is the instantaneous rolling force;

[0056] Calculate the rolling force variance:

[0057]

[0058]

[0059] Where S 2 is the rolling force variance, σ is the fluctuation allowable amplitude, and K is the variance coefficient;

[0060] when When the no-load rolling force fluctuates too much, the rolling force detection is abnormal or there is a blockage in the rolling mill transmission system, an abnormal rolling force alarm is issued.

[0061] The value of λ is based on the maximum rolling force when the rolling mill is unloaded. Generally, the rolling force when the rolling mill is unloaded does not exceed 800kN, so the value of λ is 800.

[0062] When S 2 When ≥σ, the no-load rolling force fluctuates too much, the rolling force detection is unstable and abnormal, and an abnormal rolling force alarm is issued.

[0063] Although the variance S 2 The smaller the sensor changes, the more stable it is. However, due to the jitter of the system itself and other reasons, The value is 100kn, so the maximum variance S 2 10000. In order to pursue a more stable purpose, the variance coefficient K is set here, and the variance coefficient K is set to 0.8 (based on the stability of the system, generally 0.5 to 1), so σ = 8000.

[0064] The above step S2 specifically includes:

[0065] Combined with the rolling time, speed and roller diameter of the rough rolling mill, the rolling length and distance of the involved stands are judged.

[0066]

[0067] L = πD × n × t

[0068] Where, L 后 is the length after rolling, L 前 is the original length of the strip, H 后 is the thickness after rolling, H 前 is the original thickness of the strip, L 轧 is the rolling length of the roller, D is the roller diameter, n is the roller speed, and t is the rolling time;

[0069] When L 轧 >L 后 When , strip rolling is completed.

[0070] The above step S3 specifically includes:

[0071] When the rolling force detection force of the rolling mill increases instantly, it means that the rolling mill is biting the steel and the rolling mill has entered the continuous rolling state. When the rolling force decreases instantly, it means that the rolling mill is throwing the steel and the rolling is over.

[0072] when When the mill bites steel, the mill enters the continuous rolling state;

[0073] Wherein, α is the setting value of the steel biting signal (the rolling force of the rolling mill will increase instantly after biting the steel. It depends on the size of the rolling mill and the product produced. In this embodiment, the value is 1200kN);

[0074] Calculate the average rolling force in the load state after biting the steel:

[0075]

[0076] Where, is the average rolling force when no load is applied, P i is the instantaneous rolling force;

[0077] then, The rolling mill is finished rolling steel.

[0078] The above step S4 specifically includes:

[0079] The width gauge at the rough rolling exit is used to detect the completion signal (falling edge) and make a secondary position judgment on the actual strip to determine whether the strip is abnormal.

[0080] The above step S5 specifically includes:

[0081] 1) When the rolling force detection mill completes the steel throwing rolling, if the rolling length is greater than the strip rolled length, the normal steel throwing rolling is completed; if the rolling length is less than the strip rolled length, it means that the rolling force jumps abnormally, an alarm is issued, and the width gauge is used to detect the falling edge of the completion signal instead of the steel throwing signal;

[0082] 2) When the rolling mill is in the continuous rolling state and the width gauge detection signal (falling edge) at the rough rolling outlet is triggered, the rolling length has also been reached, but the frame load judgment is still in the continuous rolling state, indicating that there is a problem with the rolling force detection. At this time, an alarm is issued and the roller is locked to avoid rushing into the finishing rolling area and causing tracking errors.

[0083] Example 1

[0084] In a certain production line, a piece of strip steel is roughly rolled in the last pass. The length before rolling is 60,000 mm and the thickness after rolling is 72 mm.

[0085] The rolling force no-load detection cycle is 50ms / the continuous sampling data within one second is:

[0086] P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 P13 P14 P15 P16 P17 P18 P19 P20

[0087] 122 -86 -12 36 94 -17 78 109 -1 -76 84 1 -59 -116 -10 49 118 38 0 -22

[0088] The average rolling force deviation is allowed, the no-load allowable deviation λ is 800kN, the variance coefficient K is 0.8, and the allowable fluctuation range is is 100kn.

[0089] The average rolling force when no-load is:

[0090]

[0091]

[0092] The rolling force deviation is normal.

[0093]

[0094]

[0095] Then S 2 <σ, rolling force fluctuation is normal.

[0096] The diameter D of the rough rolling roll is 1800, and the rotation speed is 0.5 rpm. When the instantaneous load reaches 1800 kN, the rolling mill begins to bite the steel and lasts for 27 seconds before the instantaneous rolling force returns to 10 kN.

[0097] The length of the strip after rolling is

[0098] L = πD × n × t = 3.14 × 1800 × 0.5 × 27 = 76302 mm

[0099] The rolling length is greater than the theoretical rolling length, the rolling force signal is normal, and the rolling pass is completed.

[0100] Example 2

[0101] The rolling force no-load detection cycle is 50ms / the continuous sampling data within one second is:

[0102] P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 P13 P14 P15 P16 P17 P18 P19 P20

[0103] 182 -86 -129 36 94 -17 78 199 -1 -76 84 1 -59 -186 -10 49 178 38 0 -122

[0104] The average rolling force deviation is allowed, the no-load allowable deviation λ is 800kN, the variance coefficient K is 0.8, and the allowable fluctuation range is is 100kn.

[0105] The average rolling force when no-load is:

[0106]

[0107]

[0108] The rolling force deviation is normal.

[0109]

[0110]

[0111] Then S 2 >σ, rolling force fluctuation is abnormal.

[0112] Example 3

[0113] The diameter D of the rough rolling roll is 1800, and the rotation speed is 0.5 rpm. When the instantaneous load reaches 1800 kN, the rolling mill begins to bite the steel and lasts for 22 seconds before the instantaneous rolling force returns to 10 kN.

[0114] The length of the strip after rolling is

[0115] L = πD × n × t = 3.14 × 1800 × 0.5 × 22 = 62172 mm

[0116] If the rolling length is less than the theoretical rolling length, the rolling force signal is abnormal and an alarm is issued. The rolling mill maintains the rolling state and the detection end signal of the width gauge behind the rolling mill is used as the rolling end signal. When the width gauge detection ends and the rolling length reaches the theoretical length, the rolling is completed.

[0117] Those skilled in the art should recognize that the above embodiments are merely intended to illustrate the present invention and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A method for detecting and controlling rolling force deviation of a hot rolling reversing mill, characterized in that: The following steps are involved: S1, analyzing the state of the rolling force detection device; S2, judging the rolling length of the stand; S3, determine the rack load; S4, judging the signal of the width gauge after the rolling mill; S5, comprehensively judge the steel throwing signal of the rolling mill.

2. The rolling force deviation detection and control method of a hot rolling reversing mill according to claim 1, characterized in that: The step S1 specifically includes: Calculate the average rolling force when the rolling mill is unloaded: Where, is the average rolling force when no load is applied, P i is the instantaneous rolling force; Calculate the rolling force variance: Where S 2 is the rolling force variance, σ is the fluctuation allowable amplitude, and K is the variance coefficient; when When the no-load rolling force fluctuates too much, the rolling force detection is abnormal or the rolling mill transmission system is blocked, an abnormal rolling force alarm is issued; The value of λ is based on the maximum rolling force when the rolling mill is unloaded; When S 2 When ≥σ, the no-load rolling force fluctuates too much, the rolling force detection is unstable and abnormal, and an abnormal rolling force alarm is issued.

3. The rolling force deviation detection and control method of a hot rolling reversing mill according to claim 2, characterized in that: The step S2 specifically includes: L = πD × n × t Where, L 后 is the length after rolling, L 前 is the original length of the strip, H 后 is the thickness after rolling, H 前 is the original thickness of the strip, L 轧 is the rolling length of the roller, D is the roller diameter, n is the roller speed, and t is the rolling time; When L 轧 >L 后 When , strip rolling is completed.

4. The rolling force deviation detection and control method of a hot rolling reversing mill according to claim 3, characterized in that: The step S3 specifically includes: when When the mill bites steel, the mill enters the continuous rolling state; Where, α is the setting value of the steel rolling steel bite signal; Calculate the average rolling force in the load state after biting the steel: Where, is the average rolling force when no load is applied, P i is the instantaneous rolling force; then, The rolling mill is finished rolling steel.

5. The rolling force deviation detection and control method of a hot rolling reversing mill according to claim 4, characterized in that: The step S4 specifically includes: The width gauge at the rough rolling exit is used to detect the completion signal and make a secondary position judgment on the actual strip to determine whether the strip is abnormal.

6. The rolling force deviation detection and control method of a hot rolling reversing mill according to claim 5, characterized in that: The step S5 specifically includes: When the rolling force detection mill is finished rolling the steel, if the rolling length is greater than the strip rolled length, the normal steel rolling is completed; if the rolling length is less than the strip rolled length, it means that the rolling force jumps abnormally, an alarm is issued, and the width gauge is used to detect the falling edge of the completion signal instead of the steel throwing signal; When the rolling mill is in the continuous rolling state and the width gauge detection signal at the rough rolling exit is triggered, the rolling length has also been reached, but the frame load judgment is still in the continuous rolling state, indicating that there is a problem with the rolling force detection. At this time, an alarm is issued and the roller is locked to avoid rushing into the finishing rolling area and causing tracking errors.

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