Controlled rolling method for improving rolling straightness of medium plate

Abstract

The invention discloses a controlled rolling method for improving the rolling straightness of a medium plate, which comprises the following steps of: S1, adding a control program for calculating a roll gap deviation value according to the rolling force deviation of two sides of a rolling mill in a rolling mill control system, performing 200ms filtering on the rolling force deviation value delta F to improve the control smoothness, and performing integral control on a roll gap compensation value delta H; s2, after a steel plate begins to be bitten, when the rolling force is larger than 50 tons, a steel plate bitten signal load begins to be locked, after a load signal is triggered, according to the steel plate bitten speed S, load signal delay T = L / S is automatically calculated, and then a position deviation compensation function of HGC cylinders on the two sides of a rolling mill is triggered and started; s3, adding a rolling mill main motor positive and negative rotation calibration button selection function on a rolling mill control display picture; s4, a roll gap pre-tilt compensation value is increased in the finish rolling pass; by applying the method, the straightness of the steel plate and the rolling success rate of the steel plate are greatly improved.

Description

Technical Field

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

[0002] During the rolling process of medium and thick plates, factors such as the temperature difference on both sides of the steel plate, the mechanical accuracy of the rolling mill, the offset center of gravity of the steel plate bite and the rolling process parameters can easily cause the steel plate to bend sideways and scrape the frame scrap steel due to the different metal flow rates on both sides during the rolling process, or the steel plate bends sideways and causes the width and thickness to exceed the tolerance, thereby affecting production efficiency and causing product quality loss.

[0003] In the actual production process, it is basically impossible to effectively control the rolling straightness of steel plates by simply controlling the various factors affecting the lateral bending of steel plates. At present, the lateral bending of medium and thick plate rolling is mainly controlled manually by manual visual inspection, which adjusts the roll gap difference on both sides of the rolling mill to control the lateral bending of steel plates. Due to the long-term production process of medium and thick plate rolling mills, the mechanical parts such as the rolling mill arch and work roll bearing seat are affected by the corrosion and wear of the roll cooling water, and they cannot be repaired in time, resulting in an increase in the matching clearance between the rolls and the arch. As a result, during the rolling process of steel plates, the rolls are displaced horizontally along the rolling line or the upper and lower working rolls cross, causing the actual roll gap on both sides of the rolling mill to deviate, causing the steel plates to lateral bend. At the same time, the different reciprocating rolling directions of the steel plates will change the offset direction of the working rolls to the inlet and outlet of the rolling mill, which is reflected in the different lateral bending directions of the odd and even passes of the steel plates, making it difficult for rolling operators to predict and adjust the lateral bending of the steel plates in a timely manner. At the same time, when the steel plate bites in, there is tail swinging or there is an oblique angle at the head of the steel plate biting in, and symmetrical biting cannot be achieved, which will also lead to different metal flow rates on both sides of the steel plate during the rolling process, resulting in lateral bending. Although a certain prediction is made when the steel plate bites in based on the plane shape of the steel plate, the degree of asymmetric biting is different, resulting in it being difficult to accurately predict the degree of lateral bending deformation manually, causing medium and thick steel plates to be rolled sharply and scrapped; 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, the temperature difference between the head and tail of the steel plate is large, and the metal flow rate on both sides is quite different, which can easily cause sharp bending at the head and tail and result in scrap.

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

[0005] The purpose of the present invention is to provide a controlled rolling method for improving the rolling flatness of medium and thick plates in view of the above situation. The application of this method greatly improves the flatness of steel plates and the success rate of steel plate rolling.

[0006] The specific solution of the present invention is: a controlled rolling method for improving the rolling straightness of medium and 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 perform a 200ms filter on the rolling force deviation value ΔF to improve control smoothness. At the same time, perform integral control on the roll gap compensation value ΔH to reduce the roll gap compensation control speed. The HGC cylinders on both sides of the rolling mill perform position compensation based on ΔH. According to the AGC thickness control principle of the rolling mill, 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 greater rolling force and opening the roll gap on the side with less rolling force, ensuring consistent thickness on both sides of the steel plate. S2. After the steel plate starts 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 T=L / S time is automatically calculated according to the steel plate bite speed S, and then the position deviation compensation function of the HGC cylinders on both sides of the rolling mill is triggered; S3. Add the function of selecting the forward and reverse calibration button of the main motor of the rolling mill on the rolling mill control display screen. After the rolling mill has changed the rolls, first select the reverse direction calibration, that is, the main motor is calibrated at a forward speed of -2.5m / s. When the pressing force on the transmission side and the operating side of the rolling mill reaches 1500 tons, the roll gap of the rolling mill is zeroed. When the roll gap is zeroed, the actual position S of the HGC cylinder on the transmission side is recorded. DS1 , actual position S of the HGC cylinder on the operating side os1 After the mill calibration is completed, select the positive direction calibration. When the pressing force on the transmission side and the operating side of the mill reaches 1500 tons, the mill roll gap is zeroed and the actual position S of the HGC cylinder on the transmission side is recorded. DS2 , actual position S of the HGC cylinder on the operating side os2 After the roll is changed once, the HGC cylinder positions on both sides and the roll gap tilt compensation values calculated and recorded after the second calibration of the rolling mill are adopted. Calculate, 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. Increase the roll gap pre-tilt compensation value in the finishing rolling pass. For odd-numbered rolling passes, the pre-tilt compensation value before the steel plate bites is -T; for even-numbered rolling passes, the pre-tilt compensation value before the steel plate bites is +T. This allows different pre-roll gap tilt values to be set in different rolling directions, and accurately controls the side bending direction of odd and even passes.

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

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

[0009] Furthermore, in step S1 of the present invention, ΔH=ΔF / C g , where ΔF is the rolling force deviation between the transmission side and the operating side, C g is the rolling mill bounce coefficient.

[0010] The present invention has the following beneficial effects: (1) Through this method, the side bending of steel plates during rolling is significantly improved, which greatly reduces the difficulty of manual adjustment of the side bending of steel plates by rolling operators. The straightness of steel plates is improved, the efficiency of steel plate trimming is effectively improved, and the quality loss caused by width size problems is reduced.

[0011] (2) This method greatly improves the success rate of rolling steel plates with a thickness of ≤8 mm, avoids the economic loss of thin-gauge steel plates due to side bending and scrapping, and achieves high-speed and stable rolling of thin-gauge steel plates, thereby improving the rolling efficiency of the rolling mill. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a data chart of Table 1 in an embodiment of the present invention; Figure 2 This is the data chart of Table 2 in the embodiment of the present invention. DETAILED DESCRIPTION

[0013] The following is a clear and complete description of the technical solution of the present invention in conjunction with the appendix of the present invention. It is obvious that the embodiments described are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0014] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0015] The present invention is a controlled rolling method for improving the rolling straightness of medium and thick plates, comprising the following steps: S1. Add a control program to the rolling mill control system to calculate the roll gap deviation value according to the rolling force deviation on both sides of the rolling mill, and perform 200ms filtering on the rolling force deviation value ΔF to improve the control smoothness. At the same time, perform integral control on the roll gap compensation value ΔH to reduce the roll gap compensation control speed. The HGC cylinders on both sides of the rolling mill perform position compensation according to ΔH respectively. According to the AGC thickness control principle of the rolling mill, the transmission side cylinder position H_DS-ΔH and the operating side HGC cylinder position H_OS+ΔH are used to achieve the purpose of closing the roll gap on the side with large rolling force and opening the roll gap on the side with small rolling force, thereby ensuring the thickness of both sides of the steel plate is consistent. Furthermore, in step S1 of the present invention, ΔH=ΔF / C g , where ΔF is the rolling force deviation between the transmission side and the operating side, C g is the rolling mill bounce coefficient; S2: After the steel plate starts 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 T=L / S is automatically calculated according to the steel plate bite speed S, and then the position deviation compensation function of the HGC cylinders on both sides of the rolling mill is triggered. Furthermore, in step S2 of the present invention, when the steel plate bites the rolling mill length L≥0.8m, the position deviation compensation function of the HGC cylinders on both sides of the rolling mill is started; S3. Add the function of selecting the forward and reverse calibration button of the main motor of the rolling mill on the rolling mill control display screen. After the rolling mill has changed the rolls, first select the reverse direction calibration, that is, the main motor is calibrated at a forward speed of -2.5m / s. When the pressing force on the transmission side and the operating side of the rolling mill reaches 1500 tons, the roll gap of the rolling mill is zeroed. When the roll gap is zeroed, the actual position S of the HGC cylinder on the transmission side is recorded. DS1 , actual position S of the HGC cylinder on the operating side os1 After the mill calibration is completed, select the positive direction calibration. When the pressing force on the transmission side and the operating side of the mill reaches 1500 tons, the mill roll gap is zeroed and the actual position S of the HGC cylinder on the transmission side is recorded. DS2 , actual position S of the HGC cylinder on the operating side os2 After the roll is changed once, the HGC cylinder positions on both sides and the roll gap tilt compensation values calculated and recorded after the second calibration of the rolling mill are adopted. Calculation, 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; further, in step S3 of the present invention, ΔH_ds=|S DS1 -S DS2 |, ΔH_os=|S os1 -S os2 |; S4. Increase the roll gap pre-tilt compensation value in the finishing rolling pass. For odd-numbered rolling passes, the pre-tilt compensation value before the steel plate bites is -T; for even-numbered rolling passes, the pre-tilt compensation value before the steel plate bites is +T. This allows different pre-roll gap tilt values to be set in different rolling directions, and accurately controls the side bending direction of odd and even passes.

[0016] The specific implementation of the present invention is as follows: 1. First, a control program was added to the existing mill control system to calculate the roll gap deviation based on the rolling force deviation on both sides of the mill. The rolling force deviation value ΔF was filtered for 200ms to improve control smoothness. At the same time, the roll gap compensation value ΔH was integrated to reduce the roll gap compensation control speed. The HGC cylinders on both sides of the mill were position-compensated based on ΔH. Based on the mill's AGC thickness control principle, the drive-side cylinder position H_DS - ΔH, and the operator-side HGC cylinder position H_OS + ΔH, achieved the goal of closing the roll gap on the side with greater rolling force and opening it on the side with less rolling force, ensuring consistent thickness on both sides of the steel plate.

[0017] 2. After the steel plate starts 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 T=L / S time 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. The calculation parameters are as shown in the attached Figure 1 As shown in Table 1.

[0018] 3. Add the function of selecting the forward and reverse calibration button of the main motor of the rolling mill to the rolling mill control display screen. After the rolling mill has changed the rolls, first select the reverse (BWD) direction calibration, that is, the main motor is calibrated at a forward speed of -2.5m / s. When the pressing force on the transmission side and the operating side of the rolling mill reaches 1500 tons, the roll gap of the rolling mill is zeroed. When the roll gap is zeroed, the actual position S of the HGC cylinder on the transmission side is recorded. DS1 , actual position S of the HGC cylinder on the operating side os1 After the mill calibration is completed, select the forward (FWD) direction calibration. When the pressing force on the transmission side and the operating side of the mill reaches 1500 tons, the mill roll gap is zeroed and the actual position S of the HGC cylinder on the transmission side is recorded. DS2 , actual position S of the HGC cylinder on the operating side os2 , as attached Figure 2 Table 2 shows the HGC cylinder positions on both sides and the roll gap tilt compensation value T= calculated and recorded after the mill is calibrated twice after one roll change. =(|-0.42|+|0.36|) / 2=0.39mm.

[0019] 4. Increase the roll gap pre-tilt compensation value in the finishing rolling pass. Among them, for the (1st, 3rd, 5th, 7th) odd-numbered rolling passes, the pre-tilt compensation value before the steel plate bites is -T=-0.39; for the (2nd, 4th, 6th) even-numbered rolling passes, the pre-tilt compensation value before the steel plate bites is +T=0.39. This realizes the pre-setting of different pre-roll gap tilt values in different rolling directions and the precise control of the side bending direction of odd and even passes.

[0020] In this embodiment, AGC (Automatic Gage Control): AGC is an automatic thickness control system whose primary function is to control strip thickness by adjusting the mill's roll gap, ensuring the product meets the desired thickness requirements. The AGC system detects thickness deviations in the strip and makes timely adjustments through a feedback system to eliminate thickness errors. HGC (Hydraulic Gage Control): HGC is essentially a form of hydraulic AGC, which uses a hydraulic system to control the mill's roll gap, achieving precise thickness control. HGC integrates the latest research findings in steelmaking processes, mechanics, hydraulics, automation, and electrical engineering, and is one of the key factors affecting plate and strip rolling quality and yield.

[0021] This method significantly improves plate bending during rolling, greatly reducing the difficulty for rolling operators to manually adjust plate bending. It also improves plate straightness, effectively increases plate trimming efficiency, and reduces quality losses due to width dimensional issues. This method significantly increases the success rate of rolling plate thicknesses ≤8mm, avoids the economic losses caused by scrapping and rolling of thin-gauge plate during bending, and simultaneously achieves high-speed and stable rolling of thin-gauge plates, improving mill efficiency.

Claims

1. A controlled rolling method for improving the flatness of medium and thick plate rolling, characterized in that: The following steps are involved: 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 perform a 200ms filter on the rolling force deviation value ΔF to improve control smoothness. At the same time, perform integral control on the roll gap compensation value ΔH to reduce the roll gap compensation control speed. The HGC cylinders on both sides of the rolling mill perform position compensation based on ΔH. According to the AGC thickness control principle of the rolling mill, 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 greater rolling force and opening the roll gap on the side with less rolling force, ensuring consistent thickness on both sides of the steel plate. S2. After the steel plate starts 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 T=L / S time is automatically calculated according to the steel plate bite speed S, and then the position deviation compensation function of the HGC cylinders on both sides of the rolling mill is triggered; S3. Add the function of selecting the forward and reverse calibration button of the main motor of the rolling mill on the rolling mill control display screen. After the rolling mill has changed the rolls, first select the reverse direction calibration, that is, the main motor is calibrated at a forward speed of -2.5m / s. When the pressing force on the transmission side and the operating side of the rolling mill reaches 1500 tons, the roll gap of the rolling mill is zeroed. When the roll gap is zeroed, the actual position S of the HGC cylinder on the transmission side is recorded. DS1 , actual position S of the HGC cylinder on the operating side os1 After the mill calibration is completed, select the positive direction calibration. When the pressing force on the transmission side and the operating side of the mill reaches 1500 tons, the mill roll gap is zeroed and the actual position S of the HGC cylinder on the transmission side is recorded. DS2 , actual position S of the HGC cylinder on the operating side os2 After the roll is changed once, the HGC cylinder positions on both sides and the roll gap tilt compensation values calculated and recorded after the second calibration of the rolling mill are adopted. Calculate, 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. Increase the roll gap pre-tilt compensation value in the finishing rolling pass. For odd-numbered rolling passes, the pre-tilt compensation value before the steel plate bites is -T; for even-numbered rolling passes, the pre-tilt compensation value before the steel plate bites is +T. This allows different pre-roll gap tilt values to be set in different rolling directions, and accurately controls the side bending direction of odd and even passes.

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

3. A controlled rolling method for improving the rolling flatness of medium and thick plates according to claim 1, characterized in that: In the step S3, ΔH_ds=|S DS1 -S DS2 |, ΔH_os=|S os1 -S os2 |.

4. A controlled rolling method for improving the flatness of medium and thick plate rolling according to claim 1, characterized in that: In step S1, ΔH=ΔF / C g , where ΔF is the rolling force deviation between the transmission side and the operating side, C g is the rolling mill bounce coefficient.

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