A quantitative control method for roller surface wear of pinch rollers on a hot rolling finishing line

Abstract

The present invention discloses a quantitative control method for roller surface wear of a pinch roller on a hot rolling finishing line. When the strip tension is greater than the friction force F provided by the pinch roller to the strip, the motor torque Tm of the pinch roller is controlled so that the traction force Fm of the pinch roller is always less than the friction force F provided by the pinch roller to the strip, so that the pinch roller only moves with the running speed of the strip. The present invention effectively avoids the pinch roller slippage phenomenon that causes pinch roller surface damage and steel plate surface quality problems.

Description

Technical Field

[0001] The invention relates to hot rolling finishing technology, and more specifically to a method for quantitatively controlling the roller surface wear of a pinch roller on a hot rolling finishing line. Background Art

[0002] In domestic and foreign steel enterprises, hot rolling finishing lines use a large number of tension pinch rollers to tighten the strip or balance the tension applied to the strip by other equipment. Figure 1 As shown, typically, the inlet pinch rollers of the working line at the outlet of the uncoiler need to balance the uncoiling tension, and the outlet pinch rollers (including the upper pinch roller 2 and the lower pinch roller 3) before the coiler 1 need to balance the coiling tension.

[0003] In this type of system, the uncoiler or coiler 1 is in torque control mode, the pinch roller adopts speed control mode, the pinch roller clamps the strip steel 4, and the strip steel 4 between the uncoiler, coiler 1 and the pinch roller can form strip steel tension.

[0004] The existing pinch roller control is achieved by controlling the cylinder clamping force of the pinch roller cylinder 5. The cylinder clamping force is manually adjusted according to the severity of the slip phenomenon. The main problems are as follows:

[0005] 1) When balancing the tension of the finishing line, the pinch rollers may slip, causing damage to the roller surface and quality problems of the steel plate surface:

[0006] Since the strip tension needs to be balanced by the friction force provided by the pinch rollers, when the friction force provided by the pinch rollers on the strip is less than the strip tension, slippage will occur between the strip and the roller surface of the pinch rollers. This slippage will not only cause strip surface quality problems, but also cause damage to the pinch roller surface. The damaged roller surface will aggravate the strip surface quality problems.

[0007] 2) When controlling the slippage of the pinch rollers in the finishing line, increasing the clamping force of the pinch rollers will cause severe edge waves in the strip:

[0008] Since the slippage is caused by the imbalance between the friction force provided by the pinch roller on the strip and the tension of the strip, in order to maintain the balance of the two forces, it is necessary to increase the friction force of the pinch roller on the strip, thereby increasing the clamping force of the pinch roller (friction force provided by the pinch roller on the strip = clamping force of the pinch roller x friction coefficient). However, in actual use, after increasing the clamping force of the pinch roller, the strip will have severe edge waves.

[0009] 3) When controlling the slippage of the pinch rollers in the finishing line, reducing the strip tension will cause quality defects such as strip deviation and C warping:

[0010] Similarly, in order to maintain the balance of the two forces, the strip tension needs to be reduced. However, in actual use, too low strip tension will cause quality defects such as strip deviation and C-warping, which will lead to plate quality (edge ​​waves, middle waves, C-warping, etc.). Summary of the invention

[0011] In view of the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide a method for quantitatively controlling the roller surface wear of the pinch rollers on a hot rolling finishing line, so as to effectively avoid the pinch roller slippage causing damage to the pinch roller surface and surface quality problems of the steel plate.

[0012] To achieve the above object, the present invention adopts the following technical solution:

[0013] A quantitative control method for roller surface wear of pinch rollers on a hot rolling finishing line:

[0014] When the strip tension is greater than the friction force F provided by the pinch roller on the strip, the motor torque Tm of the pinch roller is controlled so that the traction force Fm of the pinch roller is always smaller than the friction force F provided by the pinch roller on the strip, thereby achieving that the pinch roller only moves with the running speed of the strip.

[0015] Preferably, the friction force F provided by the pinch roller to the strip is obtained as follows:

[0016] N=A*P

[0017] F=N*f

[0018] In the above formula, N represents the clamping force of the pinch roller, A represents the rodless cavity area of ​​the hydraulic cylinder of the pinch roller, P represents the hydraulic working pressure of the pinch roller, and f represents the friction coefficient, which ranges from 0.1 to 0.15.

[0019] Preferably, the motor torque Tm of the pinch roller is obtained as follows:

[0020] Tm=kF*r / i

[0021] In the above formula, k represents the supplement coefficient, and its value range is 0.8 to 1.2, F represents the friction force provided by the pinch roller to the strip steel, r represents the radius of the pinch roller, and i represents the speed ratio of the pinch roller.

[0022] Preferably, the traction force Fm of the pinch roller is obtained as follows:

[0023] Fm=Tm*i / r

[0024] In the above formula, Tm represents the motor torque of the pinch roller, i represents the speed ratio of the pinch roller, and r represents the radius of the pinch roller.

[0025] Preferably, the torque limit of the motor torque Tm of the pinch roller is controlled by a torque limit controller.

[0026] The invention provides a quantitative control method for roller surface wear of pinch rollers on a hot rolling finishing line, which can effectively avoid roller surface damage and steel plate surface quality problems caused by pinch roller slippage, reduce roller wear of pinch rollers while ensuring the stability of strip surface quality, and greatly extend the service life of pinch rollers. It also has the following beneficial effects:

[0027] 1) When balancing the tension of the finishing line, prevent the pinch roller from slipping, which will cause damage to the roller surface and quality problems of the steel plate surface. Since the tension of the strip needs to be balanced by the friction force provided by the pinch roller on the strip, when the friction force provided by the pinch roller on the strip is less than the tension of the strip, and when the tension of the strip is greater than the clamping force of the pinch roller, control the pinch roller to follow the speed of the strip to eliminate the slip between the strip and the roller surface of the pinch roller;

[0028] 2) By eliminating the slippage of the pinch rollers in the finishing line, there is no need to increase the clamping force of the pinch rollers, thus avoiding severe edge waves in the strip;

[0029] 3) By eliminating the slippage of the pinch rollers in the finishing line, there is no need to reduce the strip tension, effectively avoiding quality defects such as strip deviation and C-warping. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the existing strip tension formed between the uncoiler, the coiler and the pinch roller;

[0031] Figure 2 It is a schematic diagram of the pinch roller and its drive and hydraulic structure;

[0032] Figure 3 It is a control principle block diagram of the method for quantitatively controlling the roller surface wear of the pinch roller on the hot rolling finishing line of the present invention;

[0033] Figure 4 It is a schematic flow chart of a method for quantitatively controlling the roller surface wear of a pinch roller on a hot rolling finishing line according to the present invention. DETAILED DESCRIPTION

[0034] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0035] Combination Figure 2 As shown, the present invention provides a method for quantitatively controlling the roller surface wear of the pinch roller on a hot rolling finishing line:

[0036] When the strip tension is greater than the friction force F provided by the pinch roller 6 on the strip, the motor torque Tm of the pinch roller 6 is controlled so that the traction force Fm of the pinch roller 6 is always smaller than the friction force F provided by the pinch roller 6 on the strip, so that the pinch roller 6 only moves with the running speed of the strip and there will be no slippage between the pinch roller 6 and the strip due to the speed difference between the pinch roller 6 and the strip.

[0037] The specific control steps are as follows:

[0038] 1) First calculate the friction force F provided by the pinch roller 6 to the strip;

[0039] 2) When it is determined that the friction force F provided by the pinch roller 6 on the strip is less than the traction force Fm of the pinch roller 6, the motor torque Tm of the pinch roller 6 is limited to ensure that the traction force Fm of the pinch roller 6 is always less than the friction force F provided by the pinch roller 6 on the strip.

[0040] The friction force F provided by the pinch roller 6 to the strip is obtained as follows:

[0041] N=A*P

[0042] F=N*f

[0043] In the above formula, N represents the clamping force of the pinch roller 6, A represents the rodless cavity area of ​​the hydraulic cylinder of the pinch roller 6 (including the pinch roller transmission side cylinder 7 and the pinch roller operating side cylinder 8), P represents the hydraulic working pressure of the pinch roller 6 (collected by the PLC controller from the pinch roller transmission side cylinder 7 and the pinch roller operating side cylinder 8), and f represents the friction coefficient, which ranges from 0.1 to 0.15.

[0044] The traction force Fm of the pinch roller 6 is obtained as follows:

[0045] Fm=Tm*i / r

[0046] In the above formula, Tm represents the motor torque of the pinch roller 6 (collected and obtained by the PLC controller from the pinch roller drive motor 9), i represents the speed ratio of the pinch roller 6 (collected and obtained by the PLC controller from the pinch roller reducer 10), and r represents the radius of the pinch roller 6.

[0047] From Fm=Tm*i / r, the motor torque Tm of the pinch roller 6 can be obtained:

[0048] Tm=Fm*r / i

[0049] In the above formula, Fm is the traction force of the pinch roller 6, r is the radius of the pinch roller 6, and i is the speed ratio of the pinch roller 6 (acquired by the PLC controller from the pinch roller reduction box 10).

[0050] From the above formula, we know that the traction force Fm of the pinch roller 6 needs to be smaller than the friction force F provided by the pinch roller 6 to the strip steel. Then, the friction force F provided by the pinch roller 6 to the strip steel can be substituted into the calculation formula of the traction force Fm of the pinch roller 6 to obtain the motor torque Tm of the pinch roller 6:

[0051] Tm=kF*r / i

[0052] In the above formula, F represents the friction force provided by the pinch roller 6 to the strip steel, r represents the radius of the pinch roller 6, i represents the speed ratio of the pinch roller 6 (acquired by the PLC controller from the pinch roller reducer 10), k represents the supplementary coefficient, and the value range is 0.8 to 1.2. Generally, the initial value of k is 1, and the coefficient k can be adapted according to the debugging conditions of the specific system. Only when Fm is less than F, the traction force Tm of the pinch roller 6 is calculated as the torque limit of the pinch roller drive motor 9, and the torque output of the pinch roller drive motor 9 is controlled to be no greater than the Tm value. In this way, the traction force Fm of the pinch roller 6 will be less than the friction force F provided by the pinch roller 6 to the strip, thereby completing static control. When the traction force Fm of the pinch roller 6 is less than the friction force F provided by the pinch roller 6 to the strip, the traction force Fm of the pinch roller 6 is dynamically and adaptively adjusted according to the load conditions. When the friction force F provided by the pinch roller 6 to the strip cannot balance the strip tension, since the traction force Fm of the pinch roller 6 is limited to be less than the friction force F provided by the pinch roller 6 to the strip, the pinch roller 6 will follow the strip speed and move, thereby avoiding slipping caused by the traction force Fm of the pinch roller 6 being greater than the friction force F provided by the pinch roller 6 to the strip.

[0053] Combination Figure 3 and Figure 4 As shown, the PLC controller collects the hydraulic working pressure P of the pinch roller 6, multiplies P by the rodless cavity area A of the hydraulic cylinder of the pinch roller 6, calculates the clamping force N of the pinch roller 6, multiplies N by the friction coefficient f, and calculates the friction force F provided by the pinch roller 6 to the strip. To ensure that the traction force Fm of the pinch roller 6 is less than the friction force F provided by the pinch roller 6 to the strip, it is necessary to calculate that the traction force Fm of the pinch roller 6 is less than the friction force F provided by the pinch roller 6 to the strip. Since the pinch roller drive motor 9 controls the traction force Fm of the pinch roller 6 through the motor torque Tm of the pinch roller 6, it is necessary to calculate the allowable torque Tm corresponding to the pinch roller drive motor 9, and use this allowable torque Tm as the torque limit Tm in the pinch roller drive controller to limit the torque output of the pinch roller drive motor 9. The torque limit Tm is controlled by the torque limit controller 11, and the torque limit controller 11 controls the torque output of the pinch roller drive motor 9 to be no greater than the Tm value.

[0054] The allowable torque Tm corresponding to the pinch roller drive motor 9 is calculated as follows: the traction force Fm of the pinch roller 6 multiplied by the radius r of the pinch roller 6 divided by the speed ratio i of the pinch roller 6.

[0055] Through the above control model, the traction force Fm of the pinch roller 6 will always be smaller than the friction force provided by the pinch roller 6 to the strip. When the tension of the coiler on the strip is greater than the friction force F provided by the pinch roller 6 to the strip, the pinch roller 6 will move with the speed of the steel plate to avoid damage to the roller surface of the pinch roller due to the different speeds of the pinch roller 6 and the steel plate.

[0056] Those skilled in the art should recognize that the above embodiments are only used 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 quantitatively controlling the wear of the pinch rolls on a hot rolling finishing line, characterized in that: When the strip tension is greater than the friction force F provided by the pinch roller on the strip, the motor torque Tm of the pinch roller is controlled so that the traction force Fm of the pinch roller is always smaller than the friction force F provided by the pinch roller on the strip, so that the pinch roller only moves with the running speed of the strip. The friction force F provided by the pinch roller to the strip is obtained as follows: N=A*P F=N*f In the above formula, N represents the clamping force of the pinch roller, A represents the rodless cavity area of ​​the hydraulic cylinder of the pinch roller, P represents the hydraulic working pressure of the pinch roller, and f represents the friction coefficient, which ranges from 0.1 to 0.

15. The motor torque Tm of the pinch roller is obtained as follows: Tm=kF*r / i In the above formula, k represents the supplement coefficient, the value range is 0.8~1.2, F represents the friction force provided by the pinch roller to the strip steel, r represents the radius of the pinch roller, i represents the speed ratio of the pinch roller, The traction force Fm of the pinch roller is obtained as follows: Fm=Tm*i / r In the above formula, Tm represents the motor torque of the pinch roller, i represents the speed ratio of the pinch roller, and r represents the radius of the pinch roller.

2. The method for quantitatively controlling the roller surface wear of the pinch roller on the hot rolling finishing line according to claim 1, characterized in that: The torque limit of the motor torque Tm of the pinch roller is controlled by a torque limit controller.

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