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

Abstract

The invention belongs to the technical field of steel rolling production control, and particularly relates to a working roll on-line roll shifting method for improving rolling stability, which is characterized in that the axial transverse movement force of working rolls during roll shifting is limited by controlling the roll shifting speed of the working rolls in each rack provided with a working roll shifting system; the control conditions of the roll shifting speed during the roll shifting operation of the working roll are as follows: the ratio # imgabs0 # of the roll shifting speed VS of the working roll in each rack provided with the working roll shifting system to the roll linear speed VR is controlled, and the ratio # imgabs0 # of the roll shifting speed VS of the working roll to the roll linear speed VR of the working roll is controlled according to the rolling force level of the rack on the basis of the ratio # imgabs0 #; the hierarchical level limits the ratio of VS to VR. According to the method, the roll shifting force is controlled within a reasonable range which does not affect rolling production, large-amplitude fluctuation of the roll shifting force is avoided, rapid changes of the roll gap state and the thermal convexity of the rolling mill are avoided, the stability of rolled piece deformation in the roll shifting process is improved, and plate shape defects, strip steel deviation and steel piling accidents caused by roll shifting of the working roll are reduced or avoided.

Description

Technical Field

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

[0002] Rollers are important production tools for plate and strip rolling. Severe roll wear is common in extremely harsh service environments. Roller wear not only increases roll consumption, but also destroys the original roll shape and deteriorates the roll surface quality, affecting the product shape, thickness profile and surface quality, aggravating the edge thinning of thin plate rolling and reducing the yield rate.

[0003] With the development of the thin slab headless rolling production process, the hot rolling mill work rolls need to produce continuously for 8 hours or even longer for one casting, and their working environment is worse than the service environment of the traditional hot rolling mill work rolls. Especially for the finishing stand, the rolling load and rolling length are large, and the work rolls are severely worn. In order to balance the roll wear, increase the rolling mileage and thus improve the production line efficiency, the work rolls must be shifted. Unlike the traditional hot rolling work roll shifting, the hydraulic cylinder moves the work rolls under a large rolling load during headless rolling. The work rolls will bear a large axial force, resulting in changes in the equipment and roll gap state, which has an adverse effect on rolling stability.

[0004] Rolling stability refers to the ability of the strip to accurately enter each rolling mill for rolling, with small fluctuations in rolling process parameters, a straight plate shape, no obvious deviation, and to smoothly enter the coiler. The stability of a four-roll strip mill is generally ensured by the offset distance of the center line of the working roll relative to the center line of the support roll. When the axial movement occurs, the axial force will overcome the friction between the working roll and the support roll, destroying the balance relationship of the roll system, resulting in an extremely unstable rolling state, causing irregular roll jumping, aggravated frame vibration, and production accidents such as steel running, breaking, and steel piling. It will also aggravate equipment damage and even cause serious equipment accidents, affecting the safety and life of the mill, seriously affecting the normal rolling rhythm, operating rate and yield rate, and increasing various consumption and production costs.

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

[0006] 1) It destroys the force balance of the rolling mill, making the deformation of the strip between the rolls extremely unstable, which can easily lead to uncontrolled wave shape of the rolled product. Especially when rolling thin products at a fast rolling speed, if the position of the roll shifting changes greatly, it will cause a large change in the convexity of the roll gap, seriously affecting the rolling stability, and easily causing steel running, intermediate rolling waste, steel piling accidents, or worsening the strip shape and causing product degradation.

[0007] 2) It drives the connecting shaft and the main motor rotor to form axial movement. When the axial movement of the roller is large, the excessive axial force directly acts on the thrust bearing, causing abnormal wear of the bearing, and in severe cases, it may directly burn it, seriously affecting the stable operation of the main motor.

[0008] 3) The axial force generated by the roller shifting will put the bearing in an abnormal load-bearing environment. The increase in roller shifting force will increase the axial load of the roller bearing and shorten the bearing service life. Excessive axial force will inevitably cause excessive local stress and excessive temperature rise in the bearing, resulting in local faults such as cracks, pits, and wear and tear, damage to the thrust bearing, and even serious consequences such as the bearing locking the roller, 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 working roll surface, which may result in diamond-shaped markings and even peeling of the roll surface, affecting the surface quality of the product and the stability of the production process, shortening the rolling mileage and reducing production efficiency.

[0010] In order to achieve stable production of hot-rolled endless strip, avoid plate shape defects, strip deviation and steel piling accidents caused by working roll shifting, and 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] The traditional wide strip hot rolling mill usually adopts a zigzag reciprocating roll shifting strategy, with a large roll shifting step length and speed. Since the roll shifting operation is performed during the strip rolling interval, it does not cause excessive roll shifting force and rapid changes in roll gap convexity during the rolling process, and has little impact on rolling stability. However, if this roll shifting strategy is used for headless rolling working roll shifting, a large roll shifting force will be generated, causing extremely unstable strip deformation between the rolls, seriously affecting the stability of the rolling process. Therefore, the currently commonly used roll shifting strategy is no longer suitable for hot headless rolling strip production. How to reduce the axial force during roll shifting is the prerequisite for online roll shifting of headless working rolls to achieve long-term stable rolling. Summary of the invention

[0012] In view of this, the purpose of the present invention is to provide an online working roll shifting method for improving rolling stability, reduce the lateral roll shifting force and roll shifting force fluctuation of the working roll, enhance the stability of rolled product deformation during the working roll shifting process, reduce or avoid plate shape defects, strip deviation and steel piling accidents caused by working roll shifting, extend the service life of roll bearings, improve the production stability and continuity of the continuous casting and rolling headless rolling production line, and improve economic benefits.

[0013] In order to achieve the above object, the present invention provides the following technical solutions:

[0014] Although modern strip mills are equipped with roll locking devices on the roll changing side and the main drive motor's ability to withstand axial loads on the transmission side is increased, if the axial force is slightly larger, it will still affect the rolling stability (plate shape control instability, deviation, and lateral bending during rolling). If the axial force is further increased, it may damage the equipment and affect the safe and stable operation of the rolling process.

[0015] Statistics show that excessive axial force and abnormal fluctuations lead to short life, burning of working roll thrust bearings, poor plate shape and frequent belt breakage accidents. About 80% of roller thrust bearing "burning box" damage accidents are caused by excessive axial force.

[0016] For the four-roll hot rolling mill of the thin slab continuous casting and rolling headless rolling production line, its working rolls and support rolls, working rolls and strip steel can be regarded as cylinders in contact with each other (the strip steel is equivalent to a cylinder with infinite radius). When two cylinders with parallel axes roll in contact and move axially, they must overcome the axial friction resistance between them. This axial resistance is not a general sliding friction force, but a friction force that increases with the shaft speed ratio. (V S is the working roll shifting speed, V R The influence of parameters such as the linear speed of the working roll), the normal contact load, the parameters of the rough layer on the surface of the cylinder and the static friction coefficient. In the process of applying external force to make the stationary object begin to slide relative to each other, a very small relative tangential displacement is generated between the contact bodies to reach a new stationary position. This relative tangential displacement is called pre-displacement. The size of the pre-displacement increases with the increase of the tangential load. The maximum pre-displacement when the object begins to make stable relative sliding is called the limit displacement. According to the pre-displacement-dynamic friction theory, the axial roll resistance that the axial roll shifting of the working roll of the rolling mill needs to overcome, that is, the axial lateral force that the working roll needs to apply to the roll shifting is equal to the sum of the axial friction resistance of the support roll to the working roll and the axial friction resistance of the strip to the working roll. The axial lateral force will increase with the increase of the rolling pressure and the increase of the shaft speed ratio.

[0017] After the rolling production plan is determined, the rolling force of each stand and the linear speed of the working rolls when rolling strips of various specifications are relatively determined. In order to avoid the excessive axial lateral force causing rolling instability, in a normal production run of the continuous casting and rolling headless rolling production line, for each stand equipped with a working roll shifting system, the axial lateral force when the working rolls shift can be limited by limiting the axial speed ratio. The control axial speed ratio is based on the known linear speed V of the working rolls. R To determine the working roll shifting speed V S of the limitation range, thereby achieving the purpose of limiting the axial lateral shifting force of the working roll.

[0018] A method for online work roll shifting for improving rolling stability, in which the axial lateral force of the work roll when shifting is limited by controlling the roll shifting speed of the work roll in each stand equipped with a work roll shifting system in one casting pass of a continuous casting and rolling headless rolling production line, so as to avoid rolling instability caused by excessive axial lateral force, and the roll shifting speed control conditions when the work roll performs the roll shifting operation are as follows:

[0019] Control the roll shifting speed V of the working rolls in each stand equipped with a work roll shifting system S and roller linear speed V R Ratio

[0020] When the rolling force F of a certain stand is ≥10000kN, control the

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

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

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

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

[0025] Studies have shown that when the axial force acting on the working roll is large, reaching 3.4% to 8.5% of the rolling pressure, the axial force on the working roll bearing is much greater than the radial force it is subjected to, and bearing failure or locking plate bolt breakage accidents often occur, resulting in production suspension and maintenance, which seriously affects stable production. When the axial force acting on the working roll is small, only 0.8% to 2% of the rolling pressure, the axial force on the working roll bearing is smaller than the radial force generated by the balance bar, and the risk of bearing failure or locking plate bolt breakage is smaller.

[0026] Furthermore, the present application provides a method for controlling the working roll shifting speed to improve the safety and service life of the rolling equipment and realize long-term safe and stable production, and further controls the axial lateral force of the working roll shifting operation to not exceed 2% of the rolling of the stand. According to this constraint, the preferred working roll shifting speed V S (m / s) should meet the following requirements:

[0027] Control the roll shifting speed V of the working roll of the frame S (m / s) and the roll linear speed V of the working roll of the stand R(m / s) ratio

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

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

[0030] When the rolling force F of a certain stand is ≥ 20000 kN, the shifting speed V of the working roll of the stand is controlled. S (m / s) and the roll linear speed V of the working roll of the stand R (m / s) ratio

[0031] Furthermore, the control of the working roll shifting speed is the key to controlling the axial movement force of the roll and avoiding rolling instability caused by excessive axial force. According to the pre-displacement-dynamic friction theory, when the rolling force and the linear speed of the roll are known, the smaller the working roll shifting speed, the smaller the axial force, and the more conducive to stable rolling production. However, if the working roll shifting speed is too small, the effective roll shifting amount of the roll will be small, the roll will wear concentratedly, and severe local wear will form, which will lead to the loss of plate shape and the working roll will be offline prematurely, affecting the stability and sustainability of the rolling process. In order to achieve uniform dispersion of working roll wear, the effective roll shifting stroke of the working roll within a complete casting needs to be relatively large. Based on this, this scheme further constrains the setting range of the working roll shifting speed of each frame, limiting the working roll shifting speed V of each frame. S ≥0.005mm / s, so that in a complete casting, an effective roll shifting stroke of at least 100mm or more can be achieved, which can enhance the plate shape control ability of the working roll and is conducive to stable rolling production;

[0032] The axial transverse force generated by the working roll shifting will make the deformation of the strip between the rolls extremely unstable, which may easily lead to the uncontrolled wave shape of the rolled product. Especially when the rolling speed of thin-gauge products is fast, if the position of the roll shifting changes greatly, it will cause a large change in the convexity of the roll gap, seriously affecting the rolling stability, and easily causing steel running, intermediate rolling waste, and steel piling accidents. In order to avoid excessive axial transverse force during the roll shifting process and avoid rolling instability caused by the rapid change of the roll gap during rolling, the working roll shifting speed V of each stand is further controlled. S ≤0.5mm / s.

[0033] Furthermore, during the rolling specification change operation, the frame roll gap is in a dynamic change process, and the rolling force changes greatly. If the working roll shifting operation is performed at this time, the deformation instability of the rolled product in the roll gap will be further amplified, and the axial roll shifting force will also cause a large fluctuation, which can easily cause a rolling out-of-control accident. Therefore, for each frame equipped with a working roll shifting system, the rolling specification change operation and the working roll shifting operation of any frame should be restricted from being performed at the same time.

[0034] Furthermore, excessive fluctuations in the axial roll-shifting force may lead to adverse effects such as unstable rolling state, irregular roll jumping, aggravated frame vibration, and shortened roll bearing life. According to theoretical calculations, the axial roll-shifting force of the working roll is sensitive to changes in the rolling force and the linear velocity of the working roll. In order to avoid rolling instability caused by excessive fluctuations in the axial roll-shifting force, the fluctuations in the rolling force and the linear velocity of the working roll within a single roll-shifting operation are appropriately restricted. Furthermore, the present scheme provides a restriction strategy: during the duration of a single roll-shifting operation of the working rolls of any of the frames, the rolling force F (kN) of the frame and the linear velocity V of the working rolls R (m / s) should remain relatively stable. When the fluctuation of rolling force F exceeds 10% or the linear speed V of the working roll during a single roll shifting operation, R When the fluctuation range exceeds 10%, the roller shifting operation should be stopped.

[0035] Furthermore, compared with the change of the roll shifting stroke, the roll shifting step length has less influence on the roll wear characteristic parameters. When rolling thin specifications, if the roll shifting step length is too large, the thermal crown of the workpiece will change, causing the rolled piece to deviate. In actual production, the greater the axial shifting of the working roll, the worse the product shape, which has a greater impact on the stability of the rolling process. Therefore, considering the establishment of a uniform thermal roll shape and ensuring rolling stability, the roll shifting step length should not be too large.

[0036] For headless rolling production lines, the working rolls of the finishing mill stand usually use variable crown working rolls to enhance the plate shape control capability. For variable crown working rolls, if the working roll shifting exceeds 10mm during the rolling time of a roll of steel strip, the roll gap state of the head and tail of a roll of steel strip will change greatly during the rolling production in the mill roll gap, and the rolling force distribution state and the convexity of the rolled product will change greatly, resulting in large fluctuations in the rolling process parameters during the production of a roll of steel strip, which may cause production accidents such as plate shape loss of control, deviation of rolled products, and even steel piling. Moreover, headless rolling produces a high proportion of thin-gauge products, and excessive roll shifting is not conducive to the control of thermal convexity. Therefore, this scheme further proposes a restriction requirement for the amount of roll shifting: for any complete roll of strip steel, when it is rolled through any of the rolling mills, the working roll shifting operation is controlled so that the amount of roll shifting during the strip production time does not exceed 10 mm, so as to avoid large changes in the roll gap state and thermal convexity due to excessive roll shifting during the rolling time of a roll of strip steel, thereby weakening the tendency of instability in the rolling process caused by the amount of roll shifting.

[0037] The beneficial effects of the present invention are:

[0038] The present invention provides an online working roll shifting method for improving rolling stability. According to the rolling force level of the frame, the upper limit of the ratio of the working roll shifting speed to the roll linear speed is limited in layers, so as to effectively limit the axial roll shifting force and avoid excessive roll shifting force. By limiting the minimum and maximum values ​​of the roll shifting speed, the plate shape loss-of-control caused by concentrated wear of the roll can be avoided, and the rolling instability caused by the rapid change of the roll gap can also be avoided. It is stipulated that the working roll shifting operation is not to be performed simultaneously with the rolling specification change operation, and the allowable fluctuation range of the rolling force and the working roll linear speed within the time of a single roll shifting operation is limited, so as to effectively avoid the adverse effects such as unstable rolling state, irregular roll jumping, aggravated frame vibration, shortened roll bearing life and the like caused by excessive fluctuation of the roll shifting force. Limiting the maximum roll shifting amount during the rolling production of a single coil of strip steel can effectively prevent the rapid change of the roll gap state and thermal convexity caused by excessive roll shifting, thereby improving the stability of the rolling process.

[0039] By combining the above strategies, the present invention can control the roll shifting force within a reasonable range that does not affect the rolling production, avoid large fluctuations in the roll shifting force, and avoid rapid changes in the roll gap state and thermal convexity of the rolling mill, which is beneficial to improving the stability of the deformation of the rolled piece during the roll shifting process, reducing or avoiding plate shape defects, strip deviation and steel piling accidents caused by working roll shifting, improving the safety and service life of rolling equipment, achieving long-term safe and stable production, and improving economic benefits.

[0040] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0042] Figure 1 The relationship between the theoretical calculated value of the axial lateral force of the working roll of a typical continuous casting and rolling headless rolling production line in the embodiment and the rolling force and axial speed ratio of the stand;

[0043] Figure 2 1 is the relationship (logarithmic curve) between the theoretical calculated value of the axial transverse force of the working roll of a typical continuous casting and rolling headless rolling production line in the embodiment and the rolling force of the stand and the axial speed ratio. DETAILED DESCRIPTION

[0044] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways 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 only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0045] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0046] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0047] First, according to the control range of the axial lateral force of the working roll in the actual production control of continuous casting and rolling, this scheme is based on theoretical calculation (such as Figure 1 and Figure 2 As shown in the figure, a method for setting the shifting roll speed when the working roll performs the shifting roll operation is given, which can ensure that the axial lateral shifting force of the working roll does not exceed the upper limit of the axial lateral shifting force in actual production, and can provide guidance for setting the shifting roll speed of the working roll in continuous casting and rolling headless rolling.

[0048] In a complete headless rolling casting, when the first roll of strip steel is cast and rolled, the thickness of the finished steel coil is usually thick. Then, the roll gap adjustment of the dynamic variable specification is performed at the tail of the steel coil, and the product thickness gradually transitions to thin specifications. After reaching the target thickness specification, a long period of stable production with the same specification is carried out. At the end of the casting, the roll gap adjustment of the dynamic variable specification is gradually carried out from thin to thick. Generally, with the increase of the continuous casting speed during the casting process and the reduction of the thickness of the finished product, the rolling load of each stand will increase, and the linear speed of the working rolls of each stand will also increase. Therefore, in a casting, with the change of product specifications, the rolling load and the linear speed of the working rolls will change.

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

[0050] When continuous casting just starts rolling the first roll of strip steel, the rolling force F of the F1 stand is about 1370t, and the linear speed of the working roll is about 0.6m / s. When F≥10000kN, the F1 stand roll shifting speed V should be controlled. S (m / s) and working roll linear speed V R (m / s) ratio Calculation shows that V S ≤0.13mm / s; when F≥15000kN, it should be controlled Calculation shows that V S ≤0.05mm / s; at V SUnder the constraint condition of ≤0.13mm / s, the actual rolling force of 1370t is interpolated by using two sets of data (10000kN, 0.13mm / s) and (15000kN, 0.05mm / s), and the calculated value of 0.11mm / s is used as the upper limit of the F1 stand roll shifting speed. Selecting a suitable roll shifting speed within this range can avoid excessive axial lateral force during roll shifting.

[0051] Furthermore, in order to avoid the excessive roll shifting force from having a significant impact on the safety and life of the equipment, the following method is used to further restrict the roll shifting speed to prevent the axial lateral 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; at V S Under the constraint condition of ≤0.055mm / s, the two sets of data (10000kN, 0.055mm / s) and (15000kN, 0.03mm / s) are interpolated by the actual rolling force of 1370t, and the calculated value of 0.0485mm / s is used as the upper limit of the actual set F1 frame roll shifting speed. The appropriate roll shifting speed is selected within this range.

[0053] In order to avoid serious local wear of the rolls and rapid changes in the roll gap causing plate shape instability, the final selected working roll shifting speed should be controlled at 0.005mm / s≤V S Within the range of ≤0.5mm / s.

[0054] The working roll shifting operation is controlled so that the amount of roll shifting during the strip production time does not exceed 10 mm, preferably 5 mm, to avoid the instability of the rolling process caused by a large change in the roll gap state due to excessive roll shifting during the rolling time of a roll of strip. During the actual roll shifting operation, it is not carried out simultaneously with the rolling specification change operation, and the roll shifting operation is carried out during the interval time of the rolling specification change operation. In order to avoid the unstable rolling state, irregular roll jumping, increased frame vibration, shortened roll bearing life, etc. caused by excessive fluctuations in the axial roll shifting force, during the duration of a single roll shifting operation, when the rolling force F or the working roll linear speed V R When the fluctuation amplitude exceeds 10%, stop the roll shifting operation, and resume the roll shifting operation after the rolling state stabilizes.

[0055] When the rolling specifications are changed, the roll shifting speed and roll shifting amount are reset in the above manner according to the latest rolling force and working roll linear speed corresponding to F1, and the corresponding roll shifting operation is performed.

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

[0057] By performing the working roll shifting operation using the above method, long-term stable production of continuous casting and rolling headless rolling can be achieved, and rolling instability accidents caused by online working roll shifting can be avoided.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for online work roll shifting for improving rolling stability, characterized in that: The axial lateral force of the working rolls during roll shifting is limited by controlling the roll shifting speed of the working rolls in each stand equipped with the working roll shifting system to avoid rolling instability caused by excessive axial lateral force. The roll shifting speed control conditions of the working rolls during roll shifting are as follows: Control the roll shifting speed V of each work roll in the stand equipped with a work roll shifting system S and roller linear speed V R Ratio When the rolling force F of a certain stand is ≥10000kN, control the When the rolling force F of a certain stand is ≥15000kN, control the rolling force of the stand. When the rolling force F of a certain stand is ≥ 20000kN, control the rolling force of the stand. When the rolling force F of a certain stand is ≥ 25000kN, control the rolling force of the stand. When the rolling force F of a certain stand is ≥30000kN, control the rolling force of the stand.

2. The method for online work roll shifting for improving rolling stability according to claim 1, characterized in that: Control the roll shifting speed V of each work roll in the stand equipped with a work roll shifting system S and roller linear speed V R Ratio When the rolling force F of a certain stand is ≥10000kN, control the When the rolling force F of a certain stand is ≥15000kN, control the rolling force of the stand. When the rolling force F of a certain stand is ≥ 20000kN, control the rolling force of the stand.

3. The method for online work roll shifting for improving rolling stability 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 online work roll shifting for improving rolling stability according to any one of claims 1 to 2, characterized in that: For each stand equipped with a working roll shifting system, the rolling specification changing operation and the working roll shifting operation are not carried out simultaneously.

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

6. The method for online work roll shifting for improving rolling stability according to any one of claims 1 to 2, characterized in that: In the endless rolling production of continuous casting and rolling, in the process of producing a complete roll of strip steel, the roll shifting amount of the working rolls in any frame equipped with the working roll shifting system is controlled not to exceed 10mm.

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