Axial movement control method for work rolls of an eighteen-high reversible cold rolling mill

Abstract

The application belongs to the technical field of rolling mill control, and provides an axial shifting control method for an eighteen-roller rolling mill work roll. The axial shifting force of the work roll is evaluated on site according to the levelness of the thrust bearing and the end face temperature of the thrust bearing. If the axial shifting force is not within a reasonable control range, the side support force of the hydraulic cylinder on both sides of the inlet and outlet of the upper and lower work rolls of the rolling mill is adjusted to realize the shifting of the upper and lower work rolls to the optimal direction, i.e. the operation side of the rolling mill. Through axial shifting control, the axial shifting of the work roll in single and double passes is independently controlled, and mutual interference of a group of side support compensation values in different passes is avoided. The axial shifting direction of the rolling mill is quickly and efficiently controlled, the axial shifting problem of the work roll of the rolling mill is effectively controlled, and the rolling mill failure shutdown rate caused by the work roll shifting problem is greatly reduced.

Description

Technical Field

[0001] This invention belongs to the field of rolling mill control technology, and relates to a method for controlling the axial movement of the work rolls in an 18-roll rolling mill, specifically a method for controlling the axial movement of the work rolls in an 18-roll reversible cold rolling mill. Background Technology

[0002] The 18-roll mill was developed from the 6-roll mill. It has smaller diameter work rolls with side supports and eliminates the bearing sleeve structure at the shaft diameter position of the traditional 6-roll mill. Two axial thrust mechanisms are added to the front and rear end faces of the work rolls to ensure the axial positioning of the work rolls. This allows for quick and efficient work roll replacement during production and enables the rolling of products with thinner thickness specifications, greater deformation resistance, and higher surface requirements.

[0003] Due to the relatively small diameter of the work rolls in an 18-roll mill, side support devices are added to the work rolls to ensure their radial horizontal positioning and horizontal rigidity. Figure 1 As shown, there are four sets of side support devices on each side of the upper and lower work roll inlet and outlet. Each set of side support devices includes a transverse support roll and two rows of backing bearings behind it. Depending on the type of side support device, 18-roll mills are classified as S-type, Z-type, X-type, etc. In the S6-high type 18-roll mill, each set of side support devices is controlled for position and pressure by three hydraulic cylinders installed on the mill stand. There are a total of 12 hydraulic cylinders on both sides of the upper and lower work roll inlet and outlet, all equipped with position and pressure sensors. During rolling, the measured pressure values ​​(i.e., side support forces) of the 12 hydraulic cylinders can be obtained as F1, F2 to F12. Figure 2 and Figure 3 As shown, each hydraulic cylinder corresponds to an initial position compensation value, which are δ1, δ2 to δ12 respectively.

[0004] Under current operating conditions, because the side support rollers are controlled by hydraulic cylinders, the extension of the hydraulic cylinders at different positions on the inlet and outlet sides varies, resulting in a certain angle and horizontal displacement between the centerline of the work roll and the centerline of the intermediate roll. Some torque is converted into axial force. Excessive angle and horizontal displacement will generate excessive axial force, damaging a large number of thrust bearings, causing long-term shutdowns, and resulting in dirt marks on the surface of the steel strip. Production efficiency and quality control are seriously affected, contract fulfillment rate decreases, and production costs increase significantly. The axial movement of the work roll has a significant impact on rolling stability and urgently needs to be studied and resolved. Summary of the Invention

[0005] The purpose of this invention is to provide a method for controlling the axial movement of the work rolls in an 18-roll reversible cold rolling mill, thereby rapidly and effectively improving the stability control level of the rolling process in an 18-roll reversible cold rolling mill.

[0006] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0007] A method for controlling the axial movement of the work rolls in an 18-roll reversible cold rolling mill includes:

[0008] S1. Evaluate on-site whether the axial force of the work roll is within a reasonable control range by measuring the levelness of the thrust bearing and the end face temperature of the thrust bearing. When the levelness of the thrust bearing is 0-5° and the end face temperature of the thrust bearing is ≤50℃, the axial force of the work roll is within a reasonable control range.

[0009] S2. When the thrust bearing levelness is not 0-5° and the thrust bearing end face temperature is ≤50℃, perform the axial movement control operation of the work roll, including the following steps:

[0010] S21. During single-pass rolling, by adjusting the initial position compensation value of the hydraulic cylinder within the range of -10 to +10 mm, 0 ≤ (F3-F6)-(F1-F4) and (F9-F12)-(F7-F10) ≤ 200 KN, F2 and F8 ≤ 200 KN are achieved. This enables the upper and lower work rolls to move towards the operating side, which is the optimal direction for the axial movement of the upper and lower work rolls. F1 to F12 are the measured pressure values ​​of the side support force of the 12 hydraulic cylinders on both sides of the upper and lower work roll inlet and outlet of the mill.

[0011] S22. Then, by adjusting the initial position compensation value of the hydraulic cylinder within the range of -1 to +1 mm, the horizontality of the thrust bearing is 0 to 5° and the bearing end face temperature is ≤50℃.

[0012] S23. When rolling in two passes, the initial position compensation value of the hydraulic cylinder is adjusted within the range of -10 to +10 mm to achieve 0≤(F6-F3)-(F4-F1) and (F12-F9)-(F10-F7) ≤200KN, F5 and F11≤200KN. This enables the upper and lower work rolls to move towards the operating side, which is the optimal direction for the axial movement of the upper and lower work rolls. F1 to F12 are the measured pressure values ​​of the side support force of the 12 hydraulic cylinders on both sides of the upper and lower work roll inlet and outlet of the mill.

[0013] S24. Then, by adjusting the initial position compensation value of the hydraulic cylinder within the range of -1 to +1 mm, the horizontality of the thrust bearing is made to be 0 to 5° and the bearing end face temperature is ≤50℃.

[0014] The beneficial effects of the method of the present invention are:

[0015] If the work roll moves axially toward the drive side, and the thrust bearing is damaged, the roll system needs to be pulled out, and maintenance personnel need to enter the mill to replace it. This process is time-consuming and carries significant safety risks. However, by setting the optimal axial movement direction of the work roll to the mill operating side, even if the thrust bearing fails, maintenance personnel can handle the fault efficiently and safely.

[0016] By standardizing the on-site evaluation method for the axial force of the working roll, the actual condition of the thrust bearing under various working conditions can be determined efficiently and conveniently on-site, providing a quantitative on-site evaluation for the initial position compensation value of the fine-tuning side.

[0017] Axial movement control enables independent control of the axial movement of the work roll in single and double passes, avoiding interference between a set of side support compensation values ​​in different passes.

[0018] By adopting the method of the present invention, the direction of the rolling mill roll shifting can be controlled quickly and efficiently, effectively controlling the axial shifting of the rolling mill work rolls, and significantly reducing the rolling mill shutdown rate caused by the roll shifting problem. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the mill-side support device structure in this invention;

[0020] Figure 2 This is a schematic diagram of the hydraulic system of the mill side support device in this invention;

[0021] Figure 3 and Figure 4 This is a schematic diagram of the side support force of the mill-side support device in this invention;

[0022] In the diagram: 1. Support roller; 2. Intermediate roller; 3. Work roller; 4. Backing bearing; 5. Transverse support roller; 6. Hydraulic cylinder; Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments: Example

[0024] Each side support device of the Sendevik S6-high 18-roll mill (model S6-high-1250 / 200X2100) is controlled for position and pressure by hydraulic cylinders mounted on the mill stand. These hydraulic cylinders are located on the drive side, intermediate side, and operating side, totaling 12 cylinders on both sides of the upper and lower work roll inlets and outlets, each equipped with position and pressure sensors. During rolling, the measured pressure values ​​of the side support force of these 12 hydraulic cylinders, from F1 to F12, can be obtained. Figure 3 and Figure 4 As shown, each hydraulic cylinder corresponds to an initial position compensation value, which are δ1 to δ12 respectively.

[0025] In single-pass rolling, such as Figure 4The initial position compensation values ​​δ1, δ2, and δ3 on the upper left side are +1.40, +1.00, and +1.50, respectively; the initial position compensation values ​​δ4, δ5, and δ6 on the upper right side are +0.40, +0.00, and +0.00, respectively; the initial position compensation values ​​δ7, δ8, and δ9 on the lower left side are -1.30, -1.20, and -2.13, respectively; and the initial position compensation values ​​δ10, δ11, and δ12 on the lower right side are -4.50, -4.40, and -6.00, respectively.

[0026] During double-pass rolling, the initial position compensation values ​​δ1, δ2, and δ3 on the upper left side are -1.70, +1.00, and +2.30, respectively; the initial position compensation values ​​δ4, δ5, and δ6 on the upper right side are +0.90, -0.25, and -1.30, respectively; the initial position compensation values ​​δ7, δ8, and δ9 on the lower left side are -1.70, -1.20, and -1.53, respectively; and the initial position compensation values ​​δ10, δ11, and δ12 on the lower right side are -4.60, -4.50, and -6.60, respectively.

[0027] 8.5 mm rolled to 4.6 mm, width: 2045 mm, steel grade 316, total 7 passes;

[0028] Second pass: F1 to F12 are -103KN, 120KN, -104KN, 334KN, 12KN, 375KN, 169KN, -127KN, ​​50KN, 598KN, -2KN, 486KN respectively. 0 < (F6-F3)-(F4-F1)=42KN < 200KN and 0 < (F12-F9)-(F10-F7) =7KN < 200KN. F5=12KN < 200KN and F11=-2KN < 200KN. All upper and lower work rollers are skewed towards the operating side. The thrust bearing is level at 3° and the temperature is 45℃.

[0029] The third pass: F1 to F12 are respectively 139KN, -9 KN, 180KN, 113KN, -90KN, 120KN, 494KN, 159KN, 398KN, 240KN, -4KN, 35KN, 0 < (F3-F6)-(F1-F4)=34KN<200KN and 0 < (F9-F12)-(F7-F10)=109KN<200KN, F2=-9KN and F8=159KN<200KN, all upper and lower work rolls are skewed towards the operating side, the thrust bearing is level at 2°, and the temperature is 40℃.

Claims

1. A method for controlling the axial movement of the work rolls in an 18-roll reversible cold rolling mill, characterized in that: Includes the following steps: S1. Evaluate on-site whether the axial force of the work roll is within a reasonable control range by measuring the levelness of the thrust bearing and the end face temperature of the thrust bearing. When the levelness of the thrust bearing is 0-5° and the end face temperature of the thrust bearing is ≤50℃, the axial force of the work roll is within a reasonable control range. S2. When the thrust bearing levelness is not met (0-5°) and the thrust bearing end face temperature is ≤50℃, execute the work roll axial movement control operation: S21. During single-pass rolling, by adjusting the initial position compensation value of the hydraulic cylinder within the range of -10 to +10 mm, 0 ≤ (F3-F6)-(F1-F4) and (F9-F12)-(F7-F10) ≤ 200 KN, F2 and F8 ≤ 200 KN are achieved, that is, the upper and lower work rolls are moved to the operating side of the mill in the optimal direction. Among them, F1 to F12 are the measured pressure values ​​of the side support force of the 12 hydraulic cylinders on both sides of the upper and lower work roll inlet and outlet of the mill. S22. Then, by adjusting the initial position compensation value of the hydraulic cylinder within the range of -1 to +1 mm, the horizontality of the thrust bearing is 0 to 5° and the bearing end face temperature is ≤50℃. S23. When rolling in two passes, the initial position compensation value of the hydraulic cylinder is adjusted within the range of -10 to +10 mm to achieve 0≤(F6-F3)-(F4-F1) and (F12-F9)-(F10-F7) ≤200KN, F5 and F11≤200KN, that is, to make the upper and lower work rolls move towards the mill operation side in the optimal direction. Among them, F1 to F12 are the measured pressure values ​​of the side support force of the 12 hydraulic cylinders on both sides of the upper and lower work roll inlet and outlet of the mill. S24. Then, by adjusting the initial position compensation value of the hydraulic cylinder within the range of -1 to +1 mm, the horizontality of the thrust bearing is made to be 0 to 5° and the bearing end face temperature is ≤50℃.

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