A controlled rolling method to improve the straightness of medium and heavy plates

Abstract

This invention discloses a controlled rolling method to improve the straightness of medium-thick plates, comprising the following steps: S1, adding a control program to the rolling mill control system to calculate the roll gap deviation value based on the rolling force deviation on both sides of the rolling mill, and filtering the rolling force deviation value ΔF for 200ms to improve control smoothness, while performing integral control on the roll gap compensation value ΔH; S2, after the steel plate begins to bite, when the rolling force is >50 tons, the steel plate bite signal load is locked. When the load signal is triggered, the load signal delay time T=L / S is automatically calculated based on the steel plate bite speed S, and then the HGC cylinder position deviation compensation function on both sides of the rolling mill is triggered; S3, adding a forward and reverse rotation calibration button selection function for the main motor of the rolling mill to the rolling mill control display screen; S4, adding a roll gap pre-tilt compensation value in the finishing rolling pass; The application of this method greatly improves the straightness of the steel plate and the rolling success rate of the steel plate.

Description

Technical Field

[0001] This invention relates to the field of hot rolling technology in the metallurgical industry, and in particular to a controlled rolling method for improving the straightness of medium and heavy plates. Background Technology

[0002] During the rolling process of medium and heavy plates, factors such as temperature difference between the two sides of the steel plate, mill precision, steel plate bite-off center of gravity and rolling process parameters can easily cause the steel plate to bend and scrape scrap from the mill stand due to different metal flow rates on both sides during the rolling process, or the bending of the steel plate can cause the width and thickness to exceed the tolerance, thereby affecting production efficiency and causing product quality loss.

[0003] In actual production, simply controlling the various influencing factors of steel plate rolling side bending is basically insufficient to effectively control the straightness of the rolled steel plate. Currently, the side bending of medium and heavy plate rolled steel plates is mainly controlled manually by visual inspection and adjustment of the roll gap difference on both sides of the rolling mill. However, due to the long-term production process of medium and heavy plate rolling mills, mechanical parts such as the mill stand and work roll bearing seats are affected by corrosion and wear from the rolling mill cooling water, and cannot be repaired in time. This causes an increase in the clearance between the rolls and the stand, resulting in displacement of the rolls along the horizontal direction of the rolling line or intersection of the upper and lower work rolls during the steel plate rolling process. This causes a deviation in the actual roll gap on both sides of the rolling mill, resulting in steel plate side bending. At the same time, the different forward and backward rolling directions of the steel plate will change the direction of the work roll offset towards the mill inlet and outlet, which is reflected in the different side bending directions of odd and even passes of steel plate rolling. This makes it difficult for rolling mill operators to predict and adjust the side bending of the steel plate in time. Meanwhile, if the steel plate is bitten off at the tail or at an angle, preventing symmetrical biting, it will cause different metal flow velocities on both sides of the steel plate during rolling, resulting in lateral bending. Although the shape of the steel plate can be used to make some predictions during biting, the degree of asymmetrical biting makes it difficult to accurately predict the degree of lateral bending deformation manually. This can lead to sharp bends and scrapping of medium and thick steel plates during rolling. When rolling medium and thick steel plates, the temperature uniformity of the steel plates on both sides is poor, especially in the last two passes of finishing rolling, where the temperature difference between the beginning and end of the steel plate is large. This creates a large difference in metal flow velocity on both sides, making it extremely easy for sharp bends to occur at the beginning and end, resulting in scrapping.

[0004] Therefore, it is necessary to invent an automatic rolling control method to prevent lateral bending of steel plates during the rolling process under the influence of multiple complex factors, so as to ensure that the lateral bending direction of the steel plate can be predicted in a timely and effective manner during the rolling process, and to adjust the roll gaps on both sides of the rolling mill in a timely manner to reduce the difficulty for rolling operators to adjust the shape of the steel plate and improve the flatness of the rolled steel plate. Summary of the Invention

[0005] The purpose of this invention is to provide a controlled rolling method to improve the straightness of medium and heavy plates in the above-mentioned situation. The application of this method greatly improves the straightness of steel plates and the rolling success rate of steel plates.

[0006] The specific solution of this invention is: a controlled rolling method for improving the straightness of medium-thick plates, comprising the following steps: S1. Add a control program to the rolling mill control system to calculate the roll gap deviation value based on the rolling force deviation on both sides of the rolling mill, and filter the rolling force deviation value ΔF for 200ms to improve control smoothness. At the same time, perform integral control on the roll gap compensation value ΔH to reduce the roll gap compensation adjustment speed. The HGC cylinders on both sides of the rolling mill perform position compensation based on ΔH. According to the rolling mill AGC thickness control principle, the position of the transmission side cylinder is H_DS-ΔH, and the position of the operation side HGC cylinder is H_OS+ΔH. This achieves the purpose of closing the roll gap on the side with greater rolling force and opening the roll gap on the side with less rolling force, ensuring that the thickness of the steel plate is consistent on both sides. S2. After the steel plate begins to bite in, when the rolling force is greater than 50 tons, the steel plate bite signal load is locked. When the load signal is triggered, the load signal delay time T=L / S is automatically calculated according to the steel plate bite speed S, and then the HGC cylinder position deviation compensation function on both sides of the rolling mill is triggered. S3. Add a forward / reverse calibration button selection function to the mill control display screen. After the mill roll change is completed, first select the reverse direction calibration, that is, the main motor is calibrated at a forward speed of -2.5m / s. When the pressure on both the mill drive side and the operating side reaches 1500 tons, zero the mill roll gap. When the roll gap is zeroed, record the actual position S of the HGC cylinder on the drive side. DS1 The actual position S of the HGC cylinder on the operating side os1 After the mill calibration is completed, select the positive direction for calibration. When the pressure on both the drive side and the operating side of the mill reaches 1500 tons, zero the mill roll gap and record the actual position S of the HGC cylinder on the drive side. DS2 The actual position S of the HGC cylinder on the operating side os2 After a roll change, the positions of the HGC cylinders on both sides and the roll gap tilt compensation value calculated and recorded after the mill's second calibration are taken as T= The calculation is performed, where ΔH_ds is the position deviation value of the HGC cylinder on the transmission side, and ΔH_os is the position deviation value of the HGC cylinder on the operating side. S4. Add a pre-tilt compensation value to the roll gap in the finishing rolling pass. For odd-numbered rolling passes, the pre-tilt compensation value before the steel plate bites in is -T; for even-numbered rolling passes, the pre-tilt compensation value before the steel plate bites in is +T. This realizes the pre-setting of different pre-roll gap tilt values ​​for different rolling directions, and accurately controls the side bending direction of odd and even passes.

[0007] Furthermore, in step S2 of this invention, when the steel plate bites into the mill at a length L ≥ 0.8m, the position deviation compensation function of the HGC cylinders on both sides of the mill is started.

[0008] Furthermore, in step S3 of this invention, ΔH_ds=|SDS1 -S DS2 |,ΔH_os=|S os1 -S os2 |

[0009] Furthermore, in step S1 of this invention, ΔH = ΔF / C g Where ΔF is the deviation between the rolling force on the drive side and the rolling force on the operating side, C g This represents the mill bounce coefficient.

[0010] The present invention has the following beneficial effects: (1) By using this method, the side bending of the steel plate rolling is significantly improved, greatly reducing the difficulty for steel rolling operators to manually adjust the side bending of the functional steel plate, improving the straightness of the steel plate, effectively improving the efficiency of steel plate edge cutting, and reducing the quality loss due to width dimension issues.

[0011] (2) This method greatly improves the rolling efficiency of steel plates with a thickness of ≤8mm, avoids the economic loss of scrapping the side bending frame during the rolling of thin steel plates, and improves the rolling efficiency of the mill by enabling high-speed and stable rolling of thin plates. Attached Figure Description

[0012] Figure 1 This is a data chart from Table 1 in the embodiments of the present invention; Figure 2 This is a data chart from Table 2 in this embodiment of the invention. Detailed Implementation

[0013] The technical solutions of the present invention will now be clearly and completely described in conjunction with the appendix. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0014] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0015] This invention relates to a controlled rolling method for improving the straightness of medium-thick plates, comprising the following steps: S1. A control program is added to the rolling mill control system to calculate the roll gap deviation value based on the rolling force deviation on both sides of the mill. The rolling force deviation value ΔF is filtered for 200ms to improve control smoothness. Simultaneously, integral control is applied to the roll gap compensation value ΔH to reduce the roll gap compensation adjustment speed. The HGC cylinders on both sides of the mill perform position compensation based on ΔH. According to the mill's AGC thickness control principle, the position of the transmission-side cylinder is H_DS - ΔH, and the position of the operating-side HGC cylinder is H_OS + ΔH. This achieves the purpose of closing the roll gap on the side with higher rolling force and opening the roll gap on the side with lower rolling force, ensuring consistent thickness on both sides of the steel plate. Furthermore, in step S1 of this invention, ΔH = ΔF / C g Where ΔF is the deviation between the rolling force on the drive side and the rolling force on the operating side, C g This refers to the rolling mill bounce coefficient. S2. After the steel plate begins to bite in, when the rolling force is greater than 50 tons, the steel plate bite signal load is locked. When the load signal is triggered, the load signal delay time T=L / S is automatically calculated based on the steel plate bite speed S, and then the HGC cylinder position deviation compensation function on both sides of the rolling mill is triggered. Further, in step S2 of this invention, when the steel plate bites into the rolling mill length L≥0.8m, the HGC cylinder position deviation compensation function on both sides of the rolling mill is started. S3. Add a forward / reverse calibration button selection function to the mill control display screen. After the mill roll change is completed, first select the reverse direction calibration, that is, the main motor is calibrated at a forward speed of -2.5m / s. When the pressure on both the mill drive side and the operating side reaches 1500 tons, zero the mill roll gap. When the roll gap is zeroed, record the actual position S of the HGC cylinder on the drive side. DS1 The actual position S of the HGC cylinder on the operating side os1 After the mill calibration is completed, select the positive direction for calibration. When the pressure on both the drive side and the operating side of the mill reaches 1500 tons, zero the mill roll gap and record the actual position S of the HGC cylinder on the drive side. DS2 The actual position S of the HGC cylinder on the operating side os2 After a roll change, the positions of the HGC cylinders on both sides and the roll gap tilt compensation value calculated and recorded after the mill's second calibration are taken as T= The calculation is performed, where ΔH_ds is the position deviation value of the HGC cylinder on the transmission side, and ΔH_os is the position deviation value of the HGC cylinder on the operating side; furthermore, in step S3 of this invention, ΔH_ds = |S DS1 -S DS2 |,ΔH_os=|S os1 -S os2 |; S4. Add a pre-tilt compensation value to the roll gap in the finishing rolling pass. For odd-numbered rolling passes, the pre-tilt compensation value before the steel plate bites in is -T; for even-numbered rolling passes, the pre-tilt compensation value before the steel plate bites in is +T. This realizes the pre-setting of different pre-roll gap tilt values ​​for different rolling directions, and accurately controls the side bending direction of odd and even passes.

[0016] The specific embodiments of the present invention are as follows: 1. First, add a control program to the existing rolling mill control system to calculate the roll gap deviation value based on the rolling force deviation on both sides of the mill. Filter the rolling force deviation value ΔF for 200ms to improve control smoothness. Simultaneously, perform integral control on the roll gap compensation value ΔH to reduce the roll gap compensation adjustment speed. The HGC cylinders on both sides of the mill perform position compensation based on ΔH. According to the mill's AGC thickness control principle, the position of the transmission-side cylinder is H_DS-ΔH, and the position of the operating-side HGC cylinder is H_OS+ΔH. This achieves the goal of closing the roll gap on the side with higher rolling force and opening the roll gap on the side with lower rolling force, ensuring consistent thickness on both sides of the steel plate.

[0017] 2. After the steel plate begins to bite, when the rolling force is greater than 50 tons, the steel plate bite signal load is locked. When the load signal is triggered, the load signal delay time T=L / S is automatically calculated based on the steel plate bite speed S, and then the HGC cylinder position deviation compensation function on both sides of the mill is triggered. The calculation parameters are attached. Figure 1 As shown in Table 1.

[0018] 3. Add a forward / reverse calibration button selection function to the mill control display screen. After the mill roll change is completed, first select the reverse (BWD) direction for calibration, that is, the main motor is calibrated at a forward speed of -2.5m / s. When the pressure on both the mill drive side and the operating side reaches 1500 tons, zero the mill roll gap. When the roll gap is zeroed, record the actual position S of the HGC cylinder on the drive side. DS1 The actual position S of the HGC cylinder on the operating side os1 After the mill calibration is completed, the positive (FWD) direction is selected for calibration. When the pressure on both the drive side and the operating side of the mill reaches 1500 tons, the mill roll gap is zeroed out, and the actual position S of the HGC cylinder on the drive side is recorded. DS2 The actual position S of the HGC cylinder on the operating side os2 As attached Figure 2 Table 2 shows the calculated and recorded HGC cylinder positions on both sides and roll gap tilt compensation value T after two calibrations of the mill following one roll change. =(|-0.42|+|0.36|) / 2=0.39mm.

[0019] 4. In the finishing rolling passes, a pre-tilt compensation value for the roll gap is added. Specifically, for the odd-numbered rolling passes (1, 3, 5, 7), the pre-tilt compensation value before the steel plate bites in is -T = -0.39; for the even-numbered rolling passes (2, 4, 6), the pre-tilt compensation value before the steel plate bites in is +T = 0.39. This allows for the pre-setting of different pre-tilt values ​​for different rolling directions, and precise control of the side bending direction in odd and even passes.

[0020] In this embodiment, AGC (Automatic Gage Control): AGC is an automatic thickness control system. Its main function is to control the thickness of the strip by adjusting the roll gap of the rolling mill, ensuring that the product meets the expected thickness requirements. The AGC system detects the thickness deviation of the strip and makes timely adjustments through a feedback system to eliminate thickness errors. HGC (Hydraulic Gage Control): HGC is actually a form of hydraulic AGC. It uses a hydraulic system to control the roll gap of the rolling mill, thereby achieving precise thickness control. HGC integrates the latest research results in steel rolling technology, mechanics, hydraulics, automation, and electrical engineering, and is one of the key factors affecting the quality and output of strip rolling.

[0021] This method significantly improves the side bending of steel plates during rolling, greatly reducing the difficulty for rolling mill operators to manually adjust the side bending of functional steel plates. It also enhances the straightness of the steel plates, effectively increasing the efficiency of edge trimming and reducing quality losses due to width dimensional issues. Furthermore, this method significantly improves the rolling success rate of steel plates with a thickness ≤8mm, avoiding the economic losses from scrapping and chipping during the rolling of thin-gauge steel plates. Simultaneously, it enables high-speed and stable rolling of thin-gauge steel plates, improving the rolling mill's efficiency.

Claims

1. A controlled rolling method for improving the straightness of medium-thick plates, characterized in that, It includes the following steps: S1. Add a control program to the rolling mill control system to calculate the roll gap deviation value based on the rolling force deviation on both sides of the rolling mill, and filter the rolling force deviation value ΔF for 200ms to improve control smoothness. At the same time, perform integral control on the roll gap compensation value ΔH to reduce the roll gap compensation adjustment speed. The HGC cylinders on both sides of the rolling mill perform position compensation based on ΔH. According to the rolling mill AGC thickness control principle, the position of the transmission side cylinder is H_DS-ΔH, and the position of the operation side HGC cylinder is H_OS+ΔH. This achieves the purpose of closing the roll gap on the side with greater rolling force and opening the roll gap on the side with less rolling force, ensuring that the thickness of the steel plate is consistent on both sides. S2. After the steel plate begins to bite in, when the rolling force is greater than 50 tons, the steel plate bite signal load is locked. When the load signal is triggered, the load signal delay time T=L / S is automatically calculated according to the steel plate bite speed S, and then the HGC cylinder position deviation compensation function on both sides of the rolling mill is triggered. S3. Add a forward / reverse calibration button selection function to the mill control display screen. After the mill roll change is completed, first select the reverse direction calibration, that is, the main motor is calibrated at a forward speed of -2.5m / s. When the pressure on both the mill drive side and the operating side reaches 1500 tons, zero the mill roll gap. When the roll gap is zeroed, record the actual position S of the HGC cylinder on the drive side. DS1 The actual position S of the HGC cylinder on the operating side os1 After the mill calibration is completed, select the positive direction for calibration. When the pressure on both the drive side and the operating side of the mill reaches 1500 tons, zero the mill roll gap and record the actual position S of the HGC cylinder on the drive side. DS2 The actual position S of the HGC cylinder on the operating side os2 After a roll change, the positions of the HGC cylinders on both sides and the roll gap tilt compensation value calculated and recorded after the mill's second calibration are taken as T= The calculation is performed, where ΔH_ds is the position deviation value of the HGC cylinder on the transmission side, and ΔH_os is the position deviation value of the HGC cylinder on the operating side. S4. Add a pre-tilt compensation value to the roll gap in the finishing rolling pass. For odd-numbered rolling passes, the pre-tilt compensation value before the steel plate bites in is -T; for even-numbered rolling passes, the pre-tilt compensation value before the steel plate bites in is +T. This realizes the pre-setting of different pre-roll gap tilt values ​​for different rolling directions, and accurately controls the side bending direction of odd and even passes.

2. The controlled rolling method for improving the straightness of medium-thick plates according to claim 1, characterized in that, In step S2, when the steel plate bites into the mill at a length L ≥ 0.8m, the position deviation compensation function of the HGC cylinders on both sides of the mill is started.

3. The controlled rolling method for improving the straightness of medium-thick plates according to claim 1, characterized in that, In step S3, ΔH_ds=|S DS1 -S DS2 |,ΔH_os=|S os1 -S os2 | 4. The controlled rolling method for improving the straightness of medium-thick plates according to claim 1, characterized in that: In step S1, ΔH = ΔF / C g Where ΔF is the deviation between the rolling force on the drive side and the rolling force on the operating side, C g This represents the mill bounce coefficient.

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