Work roll on-line roll shifting method for improving rolling stability

Abstract

This invention belongs to the field of steel rolling production control technology, and specifically relates to an online roll shifting method for improving rolling stability. By controlling the roll shifting speed of the work rolls in each stand equipped with a work roll shifting system, the axial lateral force during work roll shifting is limited, thus preventing excessive axial lateral force from causing rolling instability. The roll shifting speed control conditions during the work roll shifting operation are as follows: The roll shifting speed V of the work rolls in each stand equipped with the work roll shifting system is controlled... S With the linear speed V of the roll R The ratio and, based on this, the layered restrictions V according to the rolling force level of the stand. S With V R The ratio of the working roll force to the rolling mill roll gap is controlled within a reasonable range that does not affect the rolling production. This invention avoids large fluctuations in the working roll force and rapid changes in the roll gap and thermal crown. It is beneficial to improve the stability of workpiece deformation during the working roll movement and reduce or avoid plate shape defects, strip deviation and steel piling accidents caused by the working roll movement.

Description

Technical Field

[0001] This invention belongs to the field of steel rolling production control technology, and in particular relates to an online roll shifting method for improving rolling stability. Background Technology

[0002] Rolls are essential production tools in strip and sheet rolling, and severe wear is a common problem in extremely harsh operating environments. Roll wear not only increases roll consumption but also damages the original roll shape and deteriorates the roll surface quality, affecting the product's shape, thickness profile, and surface quality. It also exacerbates edge thinning in thin sheet rolling, reducing the yield.

[0003] With the development of endless rolling technology for thin slabs, hot rolling mill work rolls require continuous production for 8 hours or even longer per casting cycle, resulting in a more severe working environment compared to traditional hot continuous rolling mill work rolls. Especially in finishing mill stands, the rolling load and rolling length are large, leading to severe work roll wear. To balance roll wear, increase rolling mileage, and thus improve production line efficiency, work roll movement is necessary. Unlike traditional hot continuous rolling work roll movement, in endless rolling, hydraulic cylinder movement of the work rolls is performed under a very high rolling load. The work rolls bear significant axial forces, causing changes in equipment and roll gap conditions, adversely affecting rolling stability.

[0004] Rolling stability refers to the ability of strip steel to accurately enter each rolling mill for rolling, with minimal fluctuations in rolling process parameters, a straight strip shape, no significant deviation, and smooth entry into the coiler. The stability of a four-high strip mill is generally ensured by the offset distance between the centerline of the work roll and the centerline of the support roll. When axial movement occurs, the axial force overcomes the friction between the work roll and the support roll, disrupting the roll system balance and leading to highly unstable rolling conditions. This causes irregular roll jumping, increased stand vibration, and production accidents such as steel slippage, breakage, and steel piling. It can also exacerbate equipment damage and even cause serious equipment accidents, affecting mill safety and lifespan, severely impacting normal rolling rhythm, operating rate, and yield, and increasing various consumptions and production costs.

[0005] The impact of axial roll shifting on rolling stability and the safe and stable operation of equipment is manifested in the following aspects:

[0006] 1) Disrupting the force balance of the rolling mill makes the deformation of the strip between the rolls extremely unstable, which can easily lead to uncontrolled waviness of the rolled product. Especially when rolling thin-gauge products at high speeds, if the position of the roll shifts significantly, it will cause a large change in the roll gap crown, which will seriously affect the rolling stability and easily lead to accidents such as steel runaway, intermediate scrap, and steel piling, or worsen the strip shape and cause product downgrading.

[0007] 2) This causes axial movement of the connecting shaft and the main motor rotor. When the axial movement of the roll is large, the excessive axial force acts directly on the thrust bearing, causing abnormal wear of the bearing. In severe cases, it may burn out the bearing, seriously affecting the stable operation of the main motor.

[0008] 3) The axial force generated by the axial displacement of the rolls will place the bearings in an abnormal load environment. Increased axial force will increase the axial load on the roll bearings and shorten their service life. Excessive axial force will inevitably cause excessive local stress and temperature rise in the bearings, leading to local failures such as cracks, pits, and wear and spalling, damaging the thrust bearings, and even causing serious consequences such as the bearings seizing the rolls, which will have an adverse effect on the stable operation of the equipment.

[0009] 4) Roll shifting will also increase the stress on the roll surface, causing fatigue wear on the work roll surface, which may result in diamond-shaped marks or even roll surface peeling, affecting product surface quality and production process stability. It will also shorten the rolling mileage and reduce production efficiency.

[0010] To achieve stable production of hot-rolled endless strip steel, avoid strip shape defects, strip deviation and steel piling accidents caused by work roll shifting, extend the service life of equipment such as rolls, bearings, and main motors, and ensure long-term safe and stable rolling production, the key lies in controlling the axial roll shifting force and roll shifting speed during the online roll shifting process to avoid instability in the rolling process.

[0011] Traditional hot strip mills for wide strip typically employ a zigzag reciprocating roll shifting strategy with relatively large shifting steps and speeds. Because the shifting occurs during the strip rolling interval, it doesn't cause excessive shifting forces or rapid changes in roll gap crown during rolling, thus having minimal impact on rolling stability. However, if this strategy is used for work roll shifting in endless rolling mills, it will generate significant shifting forces, leading to highly unstable strip deformation between the rolls and severely affecting the stability of the rolling process. Therefore, the currently used roll shifting strategy is no longer suitable for hot-rolled endless strip production. Reducing the axial force during roll shifting is a prerequisite for achieving stable long-roll rolling in endless rolling mills through online roll shifting. Summary of the Invention

[0012] In view of this, the purpose of this invention is to provide a method for improving the stability of rolling by online roll shifting of work rolls, reducing the lateral shifting force and the fluctuation of the shifting force of the work rolls, enhancing the stability of workpiece deformation during the work roll shifting process, reducing or avoiding plate shape defects, strip deviation and steel piling accidents caused by work roll shifting, extending the service life of roll bearings, improving the production stability and continuity of the continuous casting and rolling headless rolling production line, and improving economic benefits.

[0013] To achieve the above objectives, the present invention provides the following technical solution:

[0014] Although modern strip mills have roll locking devices on the roll changing side and increased axial load capacity of the main drive motor on the drive side, even slightly large axial forces can still affect rolling stability (resulting in unstable strip shape control, deviation, and lateral bending during rolling). If the axial force increases further, it may damage the equipment and affect the safe and stable operation of the rolling process.

[0015] Statistical data shows that excessive axial force and abnormal fluctuations frequently lead to premature burnout, poor strip shape, and strip breakage of the work roll thrust bearings. Approximately 80% of roll thrust bearing burnout accidents are caused by excessive axial force.

[0016] For a four-high hot rolling mill in a continuous casting and rolling line for thin slabs, the work rolls and support rolls, as well as the work rolls and strip, can all be considered as cylinders in contact (the strip is equivalent to a cylinder with an infinite radius). When two parallel cylinders roll in contact and move axially, they must overcome the axial frictional resistance between them. This axial resistance is not ordinary sliding friction, but rather varies with the axial speed ratio. (V S V is the speed at which the work roll shifts. R The influence of parameters such as the working roll linear velocity, normal contact load, surface roughness parameters of the cylinder, and static friction coefficient is considered. During the process of applying an external force to cause a stationary object to begin relative sliding, a very small relative tangential displacement occurs between the contacting bodies to reach a new stationary position; this relative tangential displacement is called the pre-displacement. The magnitude of the pre-displacement increases with the increase of the tangential load. The maximum pre-displacement when the object begins stable relative sliding is called the limit displacement. According to the pre-displacement-dynamic friction theory, the axial rolling resistance that the working roll needs to overcome, i.e., the axial lateral force that needs to be applied for the working roll to move axially, is equal to the sum of the axial rolling friction resistance of the support roll on the working roll and the axial rolling friction resistance of the strip on the working roll. The axial lateral force increases with the increase of rolling pressure and the axial speed ratio.

[0017] Once the rolling production plan is determined, the rolling force and work roll linear speed of each stand when rolling strips of various specifications are relatively fixed. To avoid excessive axial lateral force causing rolling instability, in a normal production cycle of a continuous casting and rolling mill, for each stand equipped with a work roll shifting system, the axial lateral force during work roll shifting can be limited by restricting the shaft shifting speed ratio. The controlled shaft shifting speed ratio is determined based on the known work roll linear speed V. R To determine the speed V of the work roll. S The limitation range is thus used to limit the axial lateral displacement force of the work roll.

[0018] A method for improving rolling stability via online roll shifting of work rolls involves controlling the roll shifting speed of the work rolls in each stand equipped with a work roll shifting system within a single casting cycle in a continuous casting and rolling mill. This limits the axial lateral displacement force during work roll shifting, preventing excessive axial lateral displacement force from causing rolling instability. The roll shifting speed control conditions during the work roll shifting operation are as follows:

[0019] Controlling the speed V of the work rolls in each frame equipped with a work roll shifting system S With the linear speed V of the roll R ratio

[0020] And when the rolling force F of a certain stand is ≥10000kN, the control of the mill in that stand...

[0021] When the rolling force F of a certain stand is ≥15000kN, the control of the mill in that stand...

[0022] When the rolling force F of a certain stand is ≥ 20000kN, the control of the mill in that stand...

[0023] When the rolling force F of a certain stand is ≥25000kN, the control of the mill in that stand...

[0024] When the rolling force F of a certain stand is ≥30000kN, the control of the mill in that stand...

[0025] Studies have shown that when the axial force applied to the work roll is large, reaching 3.4% to 8.5% of the rolling pressure, the axial force on the work roll bearing is much greater than the radial force, frequently resulting in bearing failure or locking plate bolt breakage, requiring production shutdowns for maintenance and seriously affecting stable production. Conversely, when the axial force applied to the work roll is small, only 0.8% to 2% of the rolling pressure, the axial force on the work roll bearing is less than the radial force generated by the balance bar, and the risk of bearing failure or locking plate bolt breakage is lower.

[0026] Furthermore, this application provides a method for controlling the speed of the work roll shifting to improve the safety and service life of rolling equipment and achieve long-term safe and stable production, further controlling the axial lateral displacement force during work roll shifting operation to not exceed 2% of the rolling speed of the stand. Based on this constraint, the preferred work roll shifting speed V... S (m / s) should satisfy:

[0027] Control the speed V of the working rolls of the frame. S (m / s) and the roll linear velocity V of the work rolls of the frame RThe ratio of (m / s)

[0028] When the rolling force F of a certain stand is ≥10000kN, the speed V of the shifting rolls of the work rolls of that stand is controlled. S (m / s) and the roll linear velocity V of the work rolls of the frame R The ratio of (m / s)

[0029] When the rolling force F of a certain stand is ≥15000kN, the roll shifting speed V of the work rolls of that stand is controlled. S (m / s) and the roll linear velocity V of the work rolls of the frame R The ratio of (m / s)

[0030] When the rolling force F of a certain stand is greater than or equal to 20000kN, the speed V of the shifting rolls of the work rolls of that stand is controlled. S (m / s) and the roll linear velocity V of the work rolls of the frame R The ratio of (m / s)

[0031] Furthermore, controlling the work roll shifting speed is crucial for controlling the axial movement force of the rolls and preventing excessive axial force from causing rolling instability. According to the pre-displacement-dynamic friction theory, given the rolling force and roll linear velocity, a lower work roll shifting speed results in a lower axial force, which is more conducive to stable rolling production. However, if the work roll shifting speed is too low, the effective roll shifting amount will be small, leading to concentrated roll wear and severe localized wear. This can cause shape loss and premature roll removal, affecting the stability and sustainability of the rolling process. To achieve uniform and distributed work roll wear, a relatively large effective roll shifting stroke is required within a complete casting pass. Based on this, this scheme further constrains the setting range of the work roll shifting speed for each stand, limiting the work roll shifting speed V of each stand. S ≥0.005mm / s, so that at least 100mm or more of effective roll travel can be achieved in a complete casting cycle, which can enhance the shape control capability of the work roll and help stabilize rolling production;

[0032] The axial lateral force generated by the shifting of work rolls can cause highly unstable deformation of the strip between the rolls, easily leading to uncontrolled waviness in the rolled product. Especially when rolling thin-gauge products at high speeds, large changes in the position of the shifting rolls can cause significant changes in the roll gap crown, severely affecting rolling stability and easily leading to accidents such as steel runaway, intermediate scrap, and steel piling. To avoid excessive axial lateral force during the shifting roll process and to prevent rolling instability caused by rapid changes in the roll gap during rolling, the shifting speed V of the work rolls on each stand is further controlled. S ≤0.5mm / s.

[0033] Furthermore, during the rolling specification change operation, the roll gap of the stand is in a dynamic process, and the rolling force also changes significantly. If the work roll shifting operation is carried out at this time, it will further amplify the deformation instability of the rolled piece within the roll gap and also cause a large fluctuation in the axial shifting force, which can easily lead to rolling control failure. Therefore, for each stand equipped with a work roll shifting system, the rolling specification change operation and the work roll shifting operation of any stand should be restricted from being carried out simultaneously.

[0034] Furthermore, excessive fluctuations in axial roll force can lead to adverse effects such as unstable rolling conditions, irregular roll jumping, increased stand vibration, and shortened roll bearing life. Theoretical calculations show that the axial roll force on the work roll is highly sensitive to changes in both rolling force and work roll linear velocity. To avoid rolling instability caused by excessive fluctuations in axial roll force, appropriate limits are placed on the fluctuations in rolling force and work roll linear velocity during a single roll shifting operation. Furthermore, this solution provides a limiting strategy: during the duration of a single roll shifting operation on any stand, the rolling force F (kN) of the stand and the roll linear velocity V of the work roll are... R (m / s) should remain relatively stable. When the fluctuation range of the rolling force F exceeds 10% or the working roll linear speed V during the duration of a single roll shifting operation, the rolling force F is affected. R When the fluctuation range exceeds 10%, the roller shifting operation should be stopped.

[0035] Furthermore, compared to varying the roll travel, the roll step length has a smaller impact on the roll wear characteristic parameters. When rolling thin sheets, an excessively large roll step length can cause changes in the working roll's thermal crown, leading to workpiece misalignment. In actual production, the greater the axial movement of the work rolls, the worse the product shape, significantly impacting the stability of the rolling process. Therefore, considering the need to establish a uniform thermal roll shape and ensure rolling stability, the roll step length should not be too large.

[0036] For endless rolling mills, the finishing mill stand typically uses variable crown work rolls to enhance shape control. With variable crown work rolls, if the roll shift exceeds 10mm within the rolling time of a single strip coil, the roll gap state between the head and tail of the strip coil during rolling will change significantly. This will lead to substantial changes in the rolling force distribution and the strip crown, resulting in large fluctuations in rolling process parameters and potentially causing production accidents such as shape loss, strip misalignment, or even steel piling. Furthermore, endless rolling mills produce a high proportion of thin-gauge products, and excessive roll shift is also detrimental to thermal crown control. Therefore, this solution further proposes a limitation on the amount of roll shifting: for any complete coil of strip steel, when it is rolled through any of the rolling mills, the amount of roll shifting during the production time of the strip steel should be controlled to not exceed 10mm, so as to avoid large changes in the roll gap state and thermal crown due to excessive roll shifting during the rolling time of a coil of strip steel, thereby weakening the tendency of the rolling process to become unstable due to the amount of roll shifting.

[0037] The beneficial effects of this invention are as follows:

[0038] This invention provides a method for improving rolling stability through online roll shifting of work rolls. Based on the mill stand rolling force level, it limits the upper limit of the ratio of work roll shifting speed to roll linear speed in different layers, effectively limiting axial roll shifting force and preventing excessive force. By limiting the minimum and maximum values ​​of the roll shifting speed, it avoids strip shape loss caused by concentrated roll wear and rolling instability caused by rapid changes in roll gap. It stipulates that work roll shifting operations should not be performed simultaneously with rolling specification changes, and limits the allowable fluctuation range of rolling force and work roll linear speed within a single roll shifting operation. This effectively avoids adverse effects such as unstable rolling conditions, irregular roll jumping, increased mill stand vibration, and shortened roll bearing life caused by excessive roll shifting force fluctuations. Limiting the maximum roll shifting amount during single-coil strip rolling production effectively prevents rapid changes in roll gap condition and thermal crown caused by excessive roll shifting, thereby improving the stability of the rolling process.

[0039] By combining the above strategies, this invention can control the roll shifting force within a reasonable range that does not affect rolling production, avoid large fluctuations in roll shifting force, and prevent rapid changes in the roll gap state and thermal crown of the rolling mill. This helps to improve the stability of workpiece deformation during roll shifting, reduce or avoid plate shape defects, strip deviation and steel piling accidents caused by work roll shifting, improve the safety and service life of rolling equipment, achieve long-term safe and stable production, and improve economic benefits.

[0040] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0041] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0042] Figure 1 The example illustrates the relationship between the theoretically calculated value of the axial lateral displacement force of the work roll in a typical continuous casting and rolling headless rolling production line and the ratio of the stand rolling force to the shaft displacement speed.

[0043] Figure 2 The figure shows the relationship (logarithmic curve) between the theoretically calculated value of the axial lateral force of the work roll in a typical continuous casting and rolling headless rolling production line in the example and the ratio of the stand rolling force and the shaft speed. Detailed Implementation

[0044] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0045] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0046] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0047] First, based on the control range of the axial lateral displacement force of the work roll in the actual production control of continuous casting and rolling without end, this scheme is based on theoretical calculations (such as...). Figure 1 and Figure 2 As shown in the figure, a method for setting the speed of the work roll during the roll shifting operation is given, which can ensure that the axial lateral force of the work roll shifting does not exceed the upper limit of the axial lateral force in actual production, and can provide guidance for setting the speed of the work roll shifting in continuous casting and rolling without end.

[0048] In a continuous casting and rolling line with no end mill, when the first coil of strip is cast and rolled, the finished steel coil is typically of a thicker specification. Then, dynamic adjustment of the roll gap at the tail end of the coil gradually transitions the product thickness towards a thinner specification. After reaching the target thickness, stable production of the same specification is maintained for a relatively long period. Towards the end of the casting cycle, dynamic adjustment of the roll gap is again performed, gradually increasing the thickness from thinner to thicker. Generally, as the casting speed increases and the finished product thickness decreases, the rolling load on each stand increases, and the linear speed of the work rolls on each stand also increases. Therefore, within a single casting cycle, the rolling load and the linear speed of the work rolls will change with the change in product specifications.

[0049] For the finishing mill F1 stand equipped with a work roll shifting system, the following method can be used to control its online roll shifting:

[0050] When the continuous casting begins rolling the first coil of strip, the rolling force F of the F1 stand is approximately 1370t, and the linear speed of the work rolls is approximately 0.6m / s. When F ≥ 10000kN, the speed V of the shifting rolls on the F1 stand should be controlled. S (m / s) and the linear speed V of the working roller R The ratio of (m / s) Calculation shows that V S ≤0.13mm / s; while when F≥15000kN, it should be controlled Calculation shows that V S ≤0.05mm / s; in V SUnder the constraint of ≤0.13mm / s, the actual rolling force of 1370t is interpolated using two sets of data (10000kN, 0.13mm / s) and (15000kN, 0.05mm / s). The calculated value of 0.11mm / s is used as the upper limit of the roll shifting speed of F1 stand. Selecting an appropriate roll shifting speed within this range can avoid excessive axial lateral force during roll shifting.

[0051] Furthermore, to prevent excessive roll shifting force from significantly impacting the safety and lifespan of the equipment, the following methods are used to further constrain the roll shifting speed and prevent the axial lateral displacement force during roll shifting from exceeding 2% of the rolling force:

[0052] When F≥10000kN, control Find V S ≤0.055mm / s; when F≥15000kN, control Find V S ≤0.03mm / s; in V S Under the constraint of ≤0.055mm / s, the actual rolling force of 1370t was interpolated using two sets of data (10000kN, 0.055mm / s) and (15000kN, 0.03mm / s). The calculated value of 0.0485mm / s was used as the upper limit of the actual set F1 stand roll shifting speed. A suitable roll shifting speed was selected within this range.

[0053] To avoid severe localized wear of the rolls and rapid changes in the roll gap that could cause sheet shape instability, the final selected work roll shifting speed should be controlled within 0.005 mm / s ≤ V. S Within the range of ≤0.5mm / s.

[0054] The amount of roll shifting during strip production is controlled to not exceed 10mm, preferably 5mm, to avoid instability in the rolling process caused by significant changes in the roll gap due to excessive roll shifting within the rolling time of a single strip. In actual operation, roll shifting is not performed simultaneously with the rolling specification change operation, but rather during the interval between the rolling specification change operations. To avoid instability in the rolling state, irregular roll jumping, increased stand vibration, and shortened roll bearing life caused by excessive fluctuations in axial roll shifting force, the rolling force F or the work roll linear speed V should be controlled within the duration of a single roll shifting operation. R When the fluctuation exceeds 10%, stop the roll shifting operation and wait for the rolling state to stabilize before resuming the roll shifting operation.

[0055] When the rolling specifications change, the roll shifting speed and amount are reset according to the latest rolling force and work roll linear speed corresponding to F1, and the corresponding roll shifting operation is performed.

[0056] For other finishing mill stands equipped with a work roll shifting system, the online work roll shifting operation can also be performed in the manner described above.

[0057] By performing the above-mentioned work roll shifting operation, long-term stable production of continuous casting and rolling without end can be achieved, avoiding rolling instability accidents caused by work roll shifting online.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for improving rolling stability by online roll shifting of work rolls, characterized in that, The axial lateral force during work roll shifting is limited by controlling the shifting speed of the work rolls in each stand equipped with the work roll shifting system, in order to avoid excessive axial lateral force causing rolling instability. The shifting speed control conditions when the work rolls perform the shifting operation are as follows: Controlling the speed V of the work rolls in each frame equipped with a work roll shifting system S With the linear speed V of the roll R ratio And when the rolling force F of a certain stand is ≥10000kN, the control of the mill in that stand... When the rolling force F of a certain stand is ≥15000kN, the control of the mill in that stand... When the rolling force F of a certain stand is ≥ 20000kN, the control of the mill in that stand... When the rolling force F of a certain stand is ≥25000kN, the control of the mill in that stand... When the rolling force F of a certain stand is ≥30000kN, the control of the mill in that stand...

2. The method for improving rolling stability of work rolls by online roll shifting according to claim 1, characterized in that: Controlling the speed V of the work rolls in each frame equipped with a work roll shifting system S With the linear speed V of the roll R ratio And when the rolling force F of a certain stand is ≥10000kN, the control of the mill in that stand... When the rolling force F of a certain stand is ≥15000kN, the control of the mill in that stand... When the rolling force F of a certain stand is ≥ 20000kN, the control of the mill in that stand...

3. The method for improving rolling stability of work rolls by online roll shifting according to any one of claims 1 to 2, characterized in that: The V S The value range is 0.005mm / s ≤ V S ≤0.5mm / s.

4. The method for improving rolling stability of work rolls by online roll shifting according to any one of claims 1 to 2, characterized in that: For each stand equipped with a work roll shifting system, the rolling specification change operation and the work roll shifting operation are not performed simultaneously.

5. The method for improving rolling stability of work rolls by online roll shifting according to any one of claims 1 to 2, characterized in that: In any stand equipped with a work roll shifting system, during the duration of a single shifting operation, if the fluctuation range of the rolling force F in the corresponding stand exceeds 10% or the work roll linear velocity V... R When the fluctuation range exceeds 10%, the roller shifting operation must be stopped.

6. The method for improving rolling stability of work rolls by online roll shifting according to any one of claims 1 to 2, characterized in that: In continuous casting and rolling without end, during the production of a complete strip, the amount of roll shifting of the work roll in any stand equipped with a work roll shifting system shall not exceed 10mm.

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